JP2009015261A - Toner, method for manufacturing toner, two-component developer, developing device, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner and a method for manufacturing the toner having uniform charging characteristics and developing characteristics and stably giving images with high picture quality, and to provide a two-component developer, a developing device and an image forming apparatus. <P>SOLUTION: The toner includes: a first group of toner particles containing at least a binder resin, a colorant and a charge controlling agent insoluble with the binder resin; and a second group of toner particles containing at least a binder resin, a colorant and a charge controlling agent compatible with the binder resin, and having a volume average particle diameter smaller than that of the first group of toner particles. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a toner used for developing a latent image, a method for producing the toner, a two-component developer, a developing device, and an image forming apparatus in an image forming apparatus such as an electrophotographic system or an electrostatic printing system.

  Toner that visualizes a latent image is used in various image forming processes, and as an example, it is known to be used in an electrophotographic image forming process.

  In an image forming apparatus using an electrophotographic image forming process, generally, a charging process for uniformly charging a photosensitive layer on a surface of a photosensitive drum as a latent image carrier, and a surface of a charged photosensitive drum. An exposure process for projecting signal light of a document image to form an electrostatic latent image, a developing process for supplying an electrophotographic toner to the electrostatic latent image on the surface of the photosensitive drum to visualize it, and a toner on the surface of the photosensitive drum A transfer process for transferring an image to a recording medium such as paper or an OHP sheet, a fixing process for fixing a toner image on a recording medium by heating or pressurizing, and a toner remaining on the surface of the photosensitive drum after the toner image transfer is cleaned. A cleaning process for removing and cleaning with a blade is performed to form a desired image on the recording medium. The transfer of the toner image to the recording medium may be performed via an intermediate transfer medium.

  As the developer used in such an image forming apparatus, there are a one-component developer mainly composed of toner and a two-component developer using a mixture of toner and carrier. In addition, as a method for producing the toner used in these developers, a kneading and pulverizing method is widely used in which a toner raw material containing a binder resin, a colorant, a release agent, a charge control agent, and the like is melt-kneaded and then pulverized and classified. ing.

  In recent years, in order to obtain a higher quality image in these image forming apparatuses, the toner constituting the developer has been reduced in particle size. However, in the toner manufactured by the kneading and pulverizing method, the particle size distribution is sharp. It is difficult to obtain a small toner having a small particle diameter because it leads to the limit of grindability and classification ability and the associated cost increase. On the other hand, when the particle size distribution is broadened, the charging characteristics between the toner particle diameters are likely to vary. When an image is formed using such toner, a difference in development characteristics or a decrease in image quality due to untransferred toner occurs.

  In order to solve such problems in the kneading and pulverizing method, a method for producing a toner by a wet method such as a suspension polymerization method or an emulsion polymerization aggregation method has been proposed. However, according to such a wet method, it is possible to obtain a toner in which the broadening of the particle size distribution is suppressed as compared with the kneading and pulverizing method, but the toner has not yet reached a satisfactory particle size distribution level. Is the current situation.

  Therefore, various techniques have been proposed in order to obtain a toner having a sharp charge amount distribution in which a difference in charging characteristics between particle diameters accompanying development of a broader toner particle size distribution and a development characteristic difference associated therewith are reduced.

  For example, in Patent Document 1, a large amount of a charge control agent is contained in a large particle size toner having an average particle size of 8 μm to 20 μm with a low charging efficiency, and a charge control agent is added to a small particle size toner having an average particle size of 4 μm to 12 μm with a high charging efficiency. By mixing each of them, a non-magnetic one-component toner having an average particle diameter of 7 μm to 15 μm is obtained, which can obtain high-quality image characteristics with stable charging characteristics and development characteristics. Further, in Patent Document 2, a large charge toner having an average particle diameter of 8 μm to 20 μm with a low charging efficiency is incorporated into a large charge toner, and a low charge toner having a high charge efficiency with an average particle diameter of 4 μm to 12 μm is low. A non-magnetic one-component toner having an average particle diameter of 7 μm to 15 μm is obtained by incorporating a charge control agent and mixing them to obtain high quality image characteristics with stable charging characteristics and development characteristics. .

  Further, in Patent Document 3, a toner having a particle size distribution of about 7 μm produced by mixing at least two kinds of toner particle groups having different average particle diameters and different particle diameters of charge control agents added internally is used. By using it, the difference in the development conditions between the respective particle sizes accompanying the broadening of the toner particle size distribution is minimized, and the image density is high over a long period of time, and stable image quality without fogging of the non-image area is obtained. An electrophotographic developer is obtained.

JP-A-4-177259 JP-A-4-177260 JP 7-199520 A

  The techniques disclosed in Patent Documents 1 to 3 are effective methods for toners having an average particle diameter of about 7 μm. However, no consideration has been given to the compatibility of the charge control agent with respect to the binder resin. Therefore, when a charge control agent that is incompatible with the binder resin is used, small particles having a smaller average particle diameter are used. In a toner having a diameter, particles containing no charge control agent in the toner, particles in which the charge control agent is present on the surface of the toner particles, particles not present, and the like are mixed, and the charge stability of the toner cannot be improved.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and an object thereof is a toner that has uniform charging characteristics and development characteristics and can stably obtain a high-quality image, a method for producing the toner, and a two-component process. A developer, a developing device, and an image forming apparatus are provided.

The present invention includes a first toner particle group containing at least a binder resin, a colorant, and a charge control agent incompatible with the binder resin;
And a second toner particle group that includes at least a binder resin, a colorant, and a charge control agent that is compatible with the binder resin and has a volume average particle diameter smaller than that of the first toner particle group. The toner is characterized by the above.

In the toner of the present invention, when the average charge amount of the first toner particle group is Q _A and the average charge amount of the second toner particle group is Q _B , Q _A and Q _B are expressed by the following formula (1 ) Is satisfied.
| Q _A −Q _B | <5 (μC / g) (1)

In the toner of the present invention, the binder resin contains a polyester resin.
The present invention is also a method for producing the toner,
A first premixing step of preparing a first mixture by mixing at least a binder resin, a colorant, and a charge control agent incompatible with the binder resin;
A first melt-kneading step of producing a first melt-kneaded product by melt-kneading the first mixture;
A first pulverization step of pulverizing the first melt-kneaded product to produce a first pulverized product;
A first classification step of classifying the first pulverized product to produce a first toner particle group;
A second premixing step of preparing a second mixture by mixing a charge control agent compatible with at least the binder resin, the colorant, and the binder resin;
A second melt-kneading step of melt-kneading the second mixture to produce a second melt-kneaded product;
A second pulverization step of pulverizing the second melt-kneaded product to produce a second pulverized product;
A second classification step of classifying the second pulverized product to produce a second toner particle group having a volume average particle size smaller than that of the first toner particle group;
A toner manufacturing method comprising a mixing step of mixing a first toner particle group and a second toner particle group.

  Further, in the toner production method of the present invention, in the first premixing step, the charge control agent incompatible with the binder resin is added in an amount of 0.5% by weight based on 100% by weight of the first toner particle group. In the second pre-mixing step, the charge control agent compatible with the binder resin is added in an amount of 0.5% by weight with respect to 100% by weight of the second toner particle group. % To 5% by weight or less.

  In the toner production method of the present invention, the volume average particle size of the first toner particle group is 4 μm or more and 7 μm or less, and the volume average particle size of the second toner particle group is 3 μm or more and 5 μm or less. And

  The toner production method of the present invention is characterized in that the variation coefficient of the particle size distribution of the second toner particle group is 30% or less.

Further, in the toner production method of the present invention, in the mixing step, the first toner particle group and the second toner particle group are adjusted so that the content of the second toner particle group is 2 wt% or more and 20 wt% or less. It is characterized by mixing.
According to another aspect of the present invention, there is provided a two-component developer comprising the toner and a carrier.

In addition, the present invention is a developing device that performs development using the two-component developer.
The present invention also provides an image forming apparatus comprising the developing device.

  According to the present invention, the toner of the present invention includes a first toner particle group containing at least a binder resin, a colorant, and a charge control agent incompatible with the binder resin, and at least the binder resin and the colorant. And a second toner particle group containing a charge control agent that is compatible with the binder resin and having a volume average particle size smaller than that of the first toner particle group. As a result, in the first toner particle group having a volume average particle size larger than that of the second toner particle group and having a low charging efficiency, a large amount of charge control agent can be present on the toner particle surface, which is excellent. Charging ability can be imparted. Further, in the second toner particle group having a smaller volume average particle size and higher charging efficiency than the first toner particle group, the charge control agent can be present uniformly in all the toner particles. Can be improved. Therefore, the charging characteristics and the development characteristics are uniform, and a high-quality image can be obtained stably.

Further, according to the present invention, when the average charge amount of the first toner particle group is Q _A and the average charge amount of the second toner particle group is Q _B , Q _A and Q _B are expressed by the following formula (1 ) Is preferably satisfied.
| Q _A −Q _B | <5 (μC / g) (1)

  Thereby, since the balance of the charge amount is adjusted so as not to cause a large difference in the charge amount between the first toner particle group and the second toner particle group, the charging characteristics can be further stabilized. It is possible to suppress the occurrence of selective development in which only the toner in the charged area suitable for the development conditions is developed.

  According to the present invention, the binder resin preferably contains a polyester resin. As a result, the toner has excellent durability and color developability, and excellent low-temperature fixability that can be fixed at a lower temperature.

  According to the invention, the toner manufacturing method includes a first step of preparing a first mixture by mixing at least a binder resin, a colorant and a charge control agent incompatible with the binder resin. A mixing step, a first melt-kneading step in which the first mixture is melt-kneaded to produce a first melt-kneaded product, and a first melt-kneaded product is pulverized to produce a first pulverized product. A pulverizing step, a first grading step of classifying the first pulverized product to produce a first toner particle group, and a charge control agent compatible with at least the binder resin, the colorant, and the binder resin. A second premixing step in which a second mixture is prepared by mixing the second mixture, a second melt kneading step in which the second mixture is melt-kneaded to produce a second melt-kneaded product, and a second melt-kneading step A second pulverization step of pulverizing the product to produce a second pulverized product, and classifying the second pulverized product to obtain a first toner Than element group including a second classification step to produce a small second toner particles of a volume average particle diameter, and a mixing step of mixing a first toner particles and a second toner particles.

  As a result, the toner of the present invention can be manufactured, which has uniform charging characteristics and development characteristics, can suppress deterioration in image quality due to toner scattering and fogging, and can stably obtain a high-quality image.

  According to the invention, in the first premixing step, the charge control agent that is incompatible with the binder resin is 0.5% by weight or more and 5% by weight with respect to 100% by weight of the first toner particle group. In the second premixing step, the charge control agent compatible with the binder resin is added in an amount of 0.5% by weight or more and 5% by weight or more with respect to 100% by weight of the second toner particle group. It is preferable to mix so that it may become below weight%. Thus, by setting the mixing amount of the charge control agent in the first and second premixing steps within the above range, the charging amount of the first and second toner particle groups, that is, the large particle size side and the small particle size The charge amount of the toner having the particle size distribution on the side can be easily adjusted to an optimum value, and the charging characteristics can be easily stabilized.

  Further, according to the present invention, the volume average particle size of the first toner particle group is 4 μm or more and 7 μm or less, and the volume average particle size of the second toner particle group is 3 μm or more and 5 μm or less. The particle size distribution range of the obtained toner is 4 μm or more and 7 μm or less, and a toner capable of obtaining a higher quality image can be manufactured.

  Further, according to the present invention, the variation coefficient of the particle size distribution of the second toner particle group is preferably 30% or less. As a result, it is possible to manufacture a toner capable of limiting the amount of fine toner particles having a volume average particle diameter of 2 μm or less and preventing toner scattering due to fluidity deterioration and image quality degradation caused by deterioration in transfer efficiency.

  According to the invention, in the mixing step, the first toner particle group and the second toner particle group are mixed so that the content of the second toner particle group is 2 wt% or more and 20 wt% or less. It is preferable. As a result, the content of fine toner particles having a volume average particle diameter of 2 μm or less in the toner can be controlled in a more suitable range, and therefore, it is possible to more reliably prevent image quality degradation caused by poor fluidity and transfer efficiency. In addition, a toner capable of forming a high-definition and high-resolution high-quality image can be manufactured.

  Further, according to the present invention, the two-component developer of the present invention includes the toner and the carrier, so that the charging characteristics and the development characteristics become uniform, the deterioration in image quality due to toner scattering and fogging is suppressed, and stable high image quality is achieved. An image can be obtained.

  According to the invention, the developing device of the invention can form a high-definition and high-resolution toner image on the photoreceptor by performing development using the two-component developer.

  In addition, according to the present invention, the image forming apparatus according to the present invention is provided with the developing device, so that the charging characteristics and the developing characteristics are uniform, the image quality deterioration due to toner scattering and fogging is suppressed, and a stable high-quality image is formed. can do.

  The toner of the present invention includes a first toner particle group containing at least a binder resin, a colorant, and a charge control agent that is incompatible with the binder resin, and at least the binder resin, the colorant, and the binder resin. And a second toner particle group containing a compatible charge control agent and having a volume average particle size smaller than that of the first toner particle group.

  Generally, when a toner is manufactured by a kneading and pulverizing method, if a charge control agent that is incompatible with the binder resin is used, the charge control agent acts as a pulverization aid during the pulverization of the toner, and the charge control agent is pulverized. The starting point. For this reason, the charge control agent tends to exist at the pulverization interface of the toner, that is, the surface of the toner particle. Therefore, by adding a charge control agent incompatible with the binder resin to the first toner particle group having a volume average particle diameter larger than that of the second toner particle group and having a low charging efficiency, the toner particles Many charge control agents can be present on the surface, and excellent chargeability can be imparted.

  On the other hand, in a small particle diameter toner having a small volume average particle diameter, toner particles not containing a charge control agent and toner particles having a high charge control agent content increase, and the charge control agent content ratio between the toner particles increases. Since the difference becomes large, when a charge control agent that is incompatible with the binder resin is used, particles containing no charge control agent in the toner, particles having the charge control agent present on the toner particle surface, and Particles that do not exist are mixed, and the charging stability of the toner cannot be improved. Therefore, the second toner particle group having a smaller volume average particle diameter and higher charging efficiency than the first toner particle group contains a charge control agent that is compatible with the binder resin. In addition, since the charge control agent can be present uniformly, charging stability can be improved. As a result, the charging characteristics and the development characteristics become uniform, image quality deterioration due to toner scattering and fogging can be suppressed, and high-quality images can be stably obtained.

  Hereinafter, a method for determining whether the charge control agent is compatible or incompatible with the binder resin will be described.

  99% by weight of the binder resin and 1% by weight of the charge control agent were mixed with a Henschel mixer (trade name: FM mixer, manufactured by Mitsui Mining Co., Ltd.) for 10 minutes, and the resulting mixture was mixed with a twin-screw extrusion kneader ( After melt-kneading with a product name: PCM-65 (made by Ikegai Co., Ltd.), the mixture is cooled to room temperature and solidified to obtain a melt-kneaded product. 10 mg of the obtained melt-kneaded material was fractionated, melted on a slide glass, and sandwiched between cover glasses and spread thinly with an optical microscope (trade name: VHX-600, manufactured by Keyence Corporation) at a magnification of 2000 times When the aggregate of the charge control agent observed is approximated to an ellipse, the charge control agent when the aggregate whose major axis is 1 μm or more is confirmed is incompatible with the binder resin. It is determined that the charge control agent in the case where the aggregate is not confirmed is compatible with the binder resin.

In the toner of the present invention, when the average charge amount of the first toner particle group is Q _A and the average charge amount of the second toner particle group is Q _B , Q _A and Q _B are expressed by the following formula (1 ) Is preferably satisfied.
| Q _A −Q _B | <5 (μC / g) (1)

  Thereby, since the balance of the charge amount is adjusted so as not to cause a large difference in the charge amount between the first toner particle group and the second toner particle group, the charging characteristics can be further stabilized. It is possible to suppress the occurrence of selective development in which only the toner in the charged area suitable for the development conditions is developed.

In addition, by adjusting the type and amount of the charge control agent that is incompatible with the binder resin and the compatible charge control agent, Q _A and Q _B satisfy the above formula (1). be able to.

  In the present specification, the average charge amount is a value measured by a charge amount measuring device (trade name: 210HS-2A, manufactured by Trek Japan Co., Ltd.). The method for measuring the average charge amount is shown below.

  5% by weight of the sample (first or second toner particle group) is mixed with 95% by weight of a ferrite core carrier having a volume average particle diameter of 45 μm, and the table is placed in a room temperature and humidity environment at a temperature of 25 ° C. and a relative humidity of 50%. Stir for 30 minutes with a ball mill (Tokyo Glass Instrument Co., Ltd.). After that, the mixture of the ferrite core particles collected from the ball mill and the sample is put into a metal container having a 500 mesh conductive screen at the bottom, and only the sample is sucked at a suction pressure of 250 mmHg by a suction machine. The average charge amount of the sample is obtained from the weight difference between the weight of the mixture and the weight of the mixture after suction and the potential difference between the capacitor plates connected to the container.

  The method for producing the toner of the present invention will be described below. 1 and 2 are flowcharts showing an example of the procedure of the toner manufacturing method of the present invention. In FIG. 2, the same components as those in FIG. As shown in FIG. 1, the toner manufacturing method of the present invention is a first method in which a first mixture is prepared by mixing at least a binder resin, a colorant and a charge control agent incompatible with the binder resin. Pre-mixing step (step S1), a first melt-kneading step (step S2) in which the first mixture is melt-kneaded to produce a first melt-kneaded product, and the first melt-kneaded product is pulverized. At least a first pulverization step (step S3) for producing a first pulverized product, a first classification step (step S4) for producing a first toner particle group by classifying the first pulverized product, A second premixing step (step S5) for preparing a second mixture by mixing a charge control agent that is compatible with the adhesion resin, the colorant and the binder resin, and melt-kneading the second mixture. A second melt-kneading step (step S6) for producing a second melt-kneaded product; A second pulverization step (step S7) in which the melt-kneaded material is pulverized to produce a second pulverized material, and the second pulverized material is classified to have a volume average particle size smaller than that of the first toner particle group. A second classification step (Step S8) for producing the second toner particle group and a mixing step (Step S9) for mixing the first toner particle group and the second toner particle group are included.

  Below, each manufacturing process of step S1-step S9 is demonstrated in detail. It should be noted that the manufacturing process from Step S1 to Step S4 for producing the first toner particle group (hereinafter sometimes referred to as “first toner particle group manufacturing process”), and the second toner particle group The manufacturing process from Step S5 to Step S8 for manufacturing (hereinafter may be referred to as “second toner particle group manufacturing process”) may be performed simultaneously, or one of the manufacturing processes may be performed. It may be done first. Production of the toner of the present invention is started by moving from step S0 to step S1 or step S5, or from step S0 to step S1 and step S5.

[First and second premixing steps]
In the first pre-mixing step of Step S1, a toner mixture containing at least a binder resin, a colorant, and a charge control agent that is incompatible with the binder resin is dry-mixed by a mixer to produce a first mixture. To do. In the second premixing step of step S5, a second mixture is prepared in the same manner as in the first premixing step, except that a charge control agent that is compatible with the binder resin is used.

  The toner material may contain other toner additive components in addition to the binder resin, the colorant, and the charge control agent. Examples of other toner additive components include a release agent.

  As a mixer used for dry mixing, for example, Henschel mixer (trade name: FM mixer, manufactured by Mitsui Mining Co., Ltd.), super mixer (trade name, manufactured by Kawata Co., Ltd.), Mechano Mill (trade name, manufactured by Okada Seiko Co., Ltd.) ) Henschel type mixing equipment, ongmill (trade name, manufactured by Hosokawa Micron Corporation), hybridization system (trade name, manufactured by Nara Machinery Co., Ltd.), Cosmo system (trade name, manufactured by Kawasaki Heavy Industries, Ltd.), etc. It is done.

Hereinafter, each component of the toner raw material will be described.
(A) Binder Resin The binder resin is not particularly limited, and a binder resin for black toner or color toner can be used. For example, polyester resin, polystyrene, and styrene-acrylate ester Examples thereof include styrene resins such as copolymer resins, acrylic resins such as polymethyl methacrylate, polyolefin resins such as polyethylene, polyurethane resins, and epoxy resins. Moreover, you may use resin obtained by mixing a mold release agent with a raw material monomer mixture, and making it polymerize. Binder resin can be used individually by 1 type, or can use 2 or more types together. Among the above, the binder resin preferably contains a polyester resin. A polyester resin is superior in durability and transparency as compared with other resins such as an acrylic resin, and has a low softening point (Tm). Therefore, when the binder resin contains a polyester resin, the toner becomes excellent in durability and color developability and excellent in low-temperature fixability that can be fixed at a lower temperature.

  The glass transition point (Tg) of the binder resin is not particularly limited and can be appropriately selected from a wide range, but it is preferably 30 ° C. or higher and 80 ° C. or lower in consideration of the fixing property and storage stability of the obtained toner. . When the temperature is less than 30 ° C., the storage stability becomes insufficient, so that the toner is likely to thermally aggregate inside the image forming apparatus, which may cause development failure. Further, the temperature at which the high temperature offset phenomenon starts to occur is lowered. “High temperature offset phenomenon” means that when toner is fixed on a recording medium by heating and pressurizing with a fixing member such as a fixing roller, the cohesive force of toner particles adheres to the toner and the fixing member due to overheating of the toner. This is a phenomenon in which the toner layer is divided below the force and a part of the toner adheres to the fixing member and is removed. On the other hand, when the temperature exceeds 80 ° C., the fixing property is deteriorated, so that fixing failure may occur.

  The softening point (Tm) of the binder resin is not particularly limited and can be appropriately selected from a wide range, but is preferably 150 ° C. or lower, and more preferably 60 ° C. or higher and 150 ° C. or lower. When the temperature is less than 60 ° C., the storage stability of the toner is reduced, and the toner is likely to thermally aggregate inside the image forming apparatus, and the toner cannot be stably supplied to the latent image carrier, resulting in poor development. May occur. In addition, a failure of the image forming apparatus may be induced. If the temperature exceeds 150 ° C., the binder resin is difficult to melt in the first and second melt-kneading steps, so that kneading of the toner raw material becomes difficult, and a colorant, a release agent, a charge control agent, etc. in the kneaded product There is a possibility that the dispersibility of the resin may decrease. Further, when the toner is fixed on the recording medium, the toner is hardly melted or softened, so that the fixing property of the toner to the recording medium is lowered, and there is a possibility that a fixing defect occurs.

(B) Colorant Examples of the colorant include a yellow toner colorant, a magenta toner colorant, a cyan toner colorant, and a black toner colorant.

  Examples of the colorant for yellow toner include C.I. I. Pigment yellow 1, C.I. I. Pigment yellow 5, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 15 and C.I. I. Azo pigments such as CI Pigment Yellow 17, inorganic pigments such as yellow iron oxide and ocher; I. Nitro dyes such as Acid Yellow 1, C.I. I. Solvent Yellow 2, C.I. I. Solvent Yellow 6, C.I. I. Solvent Yellow 14, C.I. I. Solvent Yellow 15, C.I. I. Solvent Yellow 19, and C.I. I. Examples thereof include oil-soluble dyes such as Solvent Yellow 21.

  Examples of the colorant for magenta toner include C.I. I. Pigment red 49, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 57, C.I. I. Pigment red 81, C.I. I. Pigment red 122, C.I. I. Solvent Red 19, C.I. I. Solvent Red 49, C.I. I. Solvent Red 52, C.I. I. Basic Red 10 and C.I. I. Disperse Red 15 etc. are mentioned.

  Examples of the colorant for cyan toner include C.I. I. Pigment blue 15, C.I. I. Pigment blue 16, C.I. I. Solvent Blue 55, C.I. I. Solvent Blue 70, C.I. I. Direct Blue 25, and C.I. I. Direct Blue 86 and the like can be mentioned.

  Examples of the colorant for black toner include carbon black such as channel black, roller black, disk black, gas furnace black, oil furnace black, thermal black, and acetylene black. From these various types of carbon black, an appropriate carbon black may be appropriately selected according to the design characteristics of the toner to be obtained.

  In addition to these pigments, red pigments and green pigments can be used. A coloring agent can be used individually by 1 type, or can use 2 or more types together. Two or more of the same color can be used, and one or more of the different colors can also be used.

  The colorant is preferably used as a masterbatch. A master batch of a colorant can be produced, for example, by kneading a synthetic resin melt and a colorant. As the synthetic resin, the same kind of resin as the toner binder resin or a resin having good compatibility with the toner binder resin is used. The proportion of the colorant used in the masterbatch is not particularly limited, but is preferably 30 to 100 parts by weight with respect to 100 parts by weight of the synthetic resin, that is, 23 to 50% by weight with respect to 100% by weight of the masterbatch. It is as follows. The master batch is used after being granulated to a particle size of, for example, about 2 mm to 3 mm.

  The content of the colorant in the toner of the present invention is not particularly limited, but is preferably 4 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the binder resin. When using a masterbatch, it is preferable to adjust the usage amount of the masterbatch so that the content of the colorant in the toner of the present invention falls within the above range. By using the colorant in the above range, it is possible to form a good image having a sufficient image density, high color developability and excellent image quality.

(C) Charge control agent The charge control agent is internally added to make the frictional charge amount of the toner within a suitable range. As the charge control agent, a charge control agent for positive charge control or negative charge control can be used. Examples of the charge control agent for controlling positive charge include nigrosine dyes, basic dyes, quaternary ammonium salts, quaternary phosphonium salts, aminopyrines, pyrimidine compounds, polynuclear polyamino compounds, aminosilanes, nigrosine dyes and derivatives thereof, and triphenylmethane. Examples thereof include derivatives, guanidine salts, and amidine salts. Examples of the charge control agent for controlling the negative charge include oil-soluble dyes such as oil black and spiron black, metal-containing azo compounds, azo complex dyes, naphthenic acid metal salts, metal complexes and metal salts of salicylic acid and its derivatives ( Examples of the metal include chromium, zinc, zirconium, etc.), boron compounds, fatty acid soaps, long-chain alkyl carboxylates, organic bentonites, calixarene derivatives, and resin acid soaps. One charge control agent can be used alone, or two or more charge control agents can be used in combination.

  In the present invention, in the first premixing step, the charge control agent that is incompatible with the binder resin is 0.5 wt% or more and 5 wt% or less with respect to 100 wt% of the first toner particle group. It is preferable to mix so that it becomes. By setting the mixing amount of the incompatible charge control agent in the first premixing step within the above range, the charge amount of the first toner particle group, that is, the toner having a particle size distribution on the large particle size side can be easily optimized. The charging characteristics can be easily stabilized. When the mixing amount of the incompatible charge control agent exceeds 5% by weight, the charge control agent is transferred from the toner to the carrier, so that the carrier is contaminated and toner scattering may occur. Further, if it is less than 0.5% by weight, there is a possibility that sufficient charging characteristics cannot be imparted to the toner.

  In the second premixing step, a charge control agent that is compatible with the binder resin is mixed so as to be 0.5 wt% or more and 5 wt% or less with respect to 100 wt% of the second toner particle group. It is preferable to do. By setting the mixing amount of the compatible charge control agent in the second premixing step within the above range, the charge amount of the second toner particle group, that is, the toner having the particle size distribution on the small particle size side can be easily optimized. Therefore, the charging characteristics can be easily stabilized. Even if the mixing amount of the compatible charge control agent exceeds 5% by weight, no further improvement in charge performance can be expected, and the charge control agent is wasted. Further, if it is less than 0.5% by weight, there is a possibility that sufficient charging characteristics cannot be imparted to the toner.

  The compatibility of the charge control agent with the binder resin depends on the type of binder resin used, molecular weight distribution, acid value and crystallinity, molecular weight of the charge control agent used, crystallinity, presence of functional groups, basic skeleton It depends on each factor such as structure. Therefore, in the present invention, an incompatible or compatible charge control agent determined according to the above-described determination method is appropriately selected from the various charge control agents according to the binder resin to be used. That's fine.

  As a combination of a binder resin and a charge control agent that is incompatible with the binder resin used in the first premixing step, for example, a polyester resin and an organic bentonite (trade name: N4P, Clariant Japan Co., Ltd.) Product), polyester resin and calixarene derivative (trade name: BONTRON E-89, manufactured by Orient Chemical Co., Ltd.), and the like. Examples of the combination of the binder resin and the charge control agent compatible with the binder resin used in the second premixing step include, for example, a polyester resin and a metal salt of a salicylic acid derivative (trade name: BONTRON E -84, E-88, all of which are manufactured by Orient Chemical Co., Ltd.), polyester resins and boron compounds (trade name: LR-147, manufactured by Nippon Carlit Co., Ltd.).

(D) Release agent The toner raw material may contain other toner additive components such as a release agent in addition to the binder resin, the colorant, and the charge control agent. By containing a release agent, the effect of preventing offset can be enhanced. Examples of mold release agents include paraffin wax and derivatives thereof, and petroleum waxes such as microcrystalline wax and derivatives thereof, Fischer-Tropsch wax and derivatives thereof, polyolefin wax and derivatives thereof, low molecular weight polypropylene wax and derivatives thereof, and polyolefins Hydrocarbon-based synthetic waxes such as polymer waxes and derivatives thereof, carnauba wax and derivatives thereof, rice waxes and derivatives thereof, candelilla wax and derivatives thereof, plant waxes such as wood wax, animal waxes such as beeswax and whale wax Oil and fat synthetic waxes such as fatty acid amides and phenol fatty acid esters, long chain carboxylic acids and derivatives thereof, long chain alcohols and derivatives thereof, silicone polymers, high Such as a fatty acid, and the like. Derivatives include oxides, block copolymers of vinyl monomers and waxes, and copolymers of vinyl monomers and waxes. The amount of the release agent used is not particularly limited and can be appropriately selected from a wide range, but is preferably 0.2 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the binder resin.

The melting point of the release agent is preferably 50 ° C. or higher and 150 ° C. or lower, and more preferably 120 ° C. or lower. If the melting point is less than 50 ° C., the release agent may melt in the developing device, causing toner particles to aggregate and causing defects such as filming on the surface of the photosensitive drum. If the melting point exceeds 150 ° C., the release agent cannot be sufficiently eluted when the toner is fixed on the recording medium, and the effect of improving the high temperature offset resistance may not be sufficiently exhibited. Here, the melting point of the release agent is the differential scanning calorimetry (Differential
Scanning Calorimetry (abbreviation: DSC) is the temperature at the apex of the endothermic peak corresponding to melting of the DSC curve.

[First and second melt-kneading steps]
In the first melt-kneading process of step S2 and the second melt-kneading process of step S6, the first mixture produced in the first premixing process of step S1 and the second premixing process of step S5 and The second mixture is melt-kneaded to produce a first melt-kneaded product and a second melt-kneaded product. The melt kneading is performed by heating to a temperature not lower than the softening point of the binder resin and lower than the thermal decomposition temperature. Thus, the toner resin other than the binder resin such as the colorant, the charge control agent, and the release agent can be dispersed in the binder resin by melting or softening the binder resin. The specific heating temperature during melt kneading is preferably, for example, 80 ° C. or higher and 200 ° C. or lower, and more preferably 100 ° C. or higher and 150 ° C. or lower.

  For the melt-kneading, kneaders such as a kneader, a twin-screw extruder, a two-roll mill, a three-roll mill, and a lab blast mill can be used. As such a kneader, for example, TEM-100B (trade name, 1-axis or 2-axis extruder such as Toshiba Machine Co., Ltd., PCM-65, PCM-65 / 87, PCM-30 (all of which are trade names, manufactured by Ikegai Co., Ltd.), Needex (trade name, Mitsui Mine) Open roll type kneaders, etc.). Further, melt kneading may be performed using a plurality of kneaders.

[First and second grinding steps]
In the first pulverization step in step S3 and the second pulverization step in step S7, the first melt-kneaded materials produced in the first melt-kneading step in step S2 and the second melt-kneading step in step S6, respectively. The first melted product and the second melted product are pulverized to produce a first pulverized product and a second pulverized product. The first melt-kneaded product and the second melt-kneaded product are first solidified by, for example, cooling, and then first first coarsely having a volume average particle size of, for example, about 100 μm to 5 mm by a hammer mill or a cutter mill. The pulverized product and the second coarsely pulverized product are respectively pulverized. Thereafter, the obtained first coarsely pulverized product and second coarsely pulverized product are pulverized to a first pulverized product and a second pulverized product having a desired volume average particle diameter, respectively. For pulverization of the first coarsely pulverized product and the second coarsely pulverized product, for example, a jet pulverizer that pulverizes using a supersonic jet stream, a rotor (rotor) that rotates at high speed, and a stator (liner) An impact-type pulverizer that introduces and pulverizes a coarsely pulverized product into a space formed between the two can be used.

[First and second classification steps]
In the first classification step in step S4 and the second classification step in step S8, the first pulverized product and the second pulverized product produced in the first pulverization step in step S3 and the second pulverization step in step S7, respectively. Each of the pulverized products is classified to produce a first toner particle group and a second toner particle group having a volume average particle size smaller than that of the first toner particle group.

  The first classification step is preferably performed such that the volume average particle size of the first toner particle group obtained after classification is 4 μm or more and 7 μm or less by appropriately adjusting the classification conditions. When the volume average particle size of the first toner particle group is less than 4 μm, the content of small particle size particles in the toner becomes excessive, and the cleaning property may be deteriorated. If it exceeds 7 μm, a high-definition image may not be obtained. Further, since the specific surface area of the toner particles is reduced and the charge amount of the toner is reduced, the toner is not stably supplied to the latent image carrier, and there is a possibility that internal contamination due to toner scattering occurs.

  The second classification step is preferably performed so that the classification condition is appropriately adjusted so that the volume average particle size of the second toner particle group obtained after the classification is 3 μm or more and 5 μm or less. If the volume average particle size of the second toner particle group is less than 3 μm, the content of small particle size particles in the toner becomes too large, and the cleaning property may be deteriorated. If it exceeds 7 μm, there is a possibility that a high-definition image cannot be obtained. Further, since the specific surface area of the toner particles is reduced and the charge amount of the toner is reduced, the toner is not stably supplied to the latent image carrier, and there is a possibility that internal contamination due to toner scattering occurs.

When the volume average particle size of the first and second toner particle groups satisfies the above range, the particle size distribution range of the toner obtained after the mixing step is 4 μm or more and 7 μm or less, and a toner capable of obtaining a higher quality image. Can be manufactured.
.

  The classification condition to be adjusted is, for example, the rotational speed of the classification rotor in a swirl type wind classifier (rotary type wind classifier).

  Further, the coefficient of variation (CV value) of the particle size distribution of the second toner particle group is preferably 30% or less. When the variation coefficient of the particle size distribution of the second toner particle group satisfies the above range, the amount of fine toner particles having a volume average particle size of 2 μm or less is limited, and the toner scattering due to a decrease in fluidity or transfer efficiency is deteriorated. A toner capable of preventing deterioration in image quality can be manufactured.

  If the variation coefficient of the particle size distribution of the second toner particle group exceeds 30%, the amount of the fine powder toner particles becomes excessive, which may cause toner scattering due to fluidity deterioration and image quality deterioration due to transfer efficiency deterioration. is there.

In this specification, the volume average particle diameter and the coefficient of variation (CV value) are values measured by a particle size distribution measuring apparatus “Multisizer 2” manufactured by Beckman Coulter, Inc. In the present specification, the volume average particle diameter indicates a particle diameter D _{50V at} which the cumulative volume from the large particle diameter side in the cumulative volume distribution becomes 50%. The measurement conditions of the volume average particle diameter (D _50V ) and the coefficient of variation (CV value) are shown below.
Aperture diameter: 100 μm
Measurement particle number: 50000 count Analysis software: Coulter Multisizer AccuComp version 1.19 (manufactured by Beckman Coulter, Inc.)
Electrolyte: ISOTON-II (Beckman Coulter, Inc.)
Dispersant: Sodium alkyl ether sulfate Measurement method: Add 50 ml of electrolyte, 20 mg of sample, and 1 ml of dispersant to a beaker, and use ultrasonic disperser (trade name: UH-50, manufactured by SMT Corporation) at an ultrasonic frequency of 20 kHz. The sample for measurement is prepared by dispersion treatment for 3 minutes, the particle size is measured by the apparatus “Multisizer 2”, the volume particle size distribution of the sample particles is obtained from the obtained measurement result, and the obtained volume particle size distribution or volume average particle is obtained. The diameter (D _50V ) was calculated. Moreover, the standard deviation in volume particle size distribution was calculated | required, and the variation coefficient (CV value,%) was computed based on following formula (2). The coefficient of variation means that the smaller the value, the narrower the particle size distribution width.
CV value (%) = {standard deviation in volume particle size distribution / volume average particle size (μm)} × 100
... (2)

[Mixing process]
In the mixing step of Step S9, the first toner particle group and the second toner particle group produced in the first classification step of Step S4 and the second classification step of Step S8 are mixed, and thereby the present invention. Toner is manufactured.

  As a mixer used in the mixing step, for example, Henschel mixer (trade name: FM mixer, manufactured by Mitsui Mining Co., Ltd.), super mixer (trade name, manufactured by Kawata Co., Ltd.), Mechano Mill (trade name, Okada Seiko Co., Ltd.) Hengshell type mixing devices such as HONSHELL type (trade name, manufactured by Hosokawa Micron Corporation), hybridization system (trade name, manufactured by Nara Machinery Co., Ltd.), Cosmo system (trade name, manufactured by Kawasaki Heavy Industries, Ltd.), etc. Can be mentioned.

  In the mixing step, it is preferable to mix the first toner particle group and the second toner particle group so that the content of the second toner particle group is 2 wt% or more and 20 wt% or less.

  As a result, the content of fine toner particles having a volume average particle diameter of 2 μm or less in the toner can be controlled in a more suitable range, and therefore, it is possible to more reliably prevent image quality degradation caused by poor fluidity and transfer efficiency. In addition, a toner capable of forming a high-definition and high-resolution high-quality image can be manufactured. If the content of the second toner particles is less than 2% by weight, the content of the fine powder toner particles becomes insufficient, and there is a possibility that a high-quality image with sufficiently high definition and high resolution cannot be obtained. is there. On the other hand, if the content exceeds 20% by weight, the content of fine toner particles is excessively increased, so that the fluidity is lowered and the image quality may be deteriorated due to poor transfer efficiency.

  Toners manufactured as described above are external additives that perform functions such as powder flowability improvement, triboelectric chargeability improvement, heat resistance improvement, long-term storage stability improvement, cleaning property improvement and photoreceptor drum surface wear property control. An agent may be mixed. Examples of the external additive include silica fine powder, titanium oxide fine powder, and alumina fine powder. External additives can be used alone or in combination of two or more. The addition amount of the external additive is 2 with respect to 100 parts by weight of the toner in consideration of the charge amount necessary for the toner, the influence on the abrasion of the photosensitive drum by adding the external additive, the environmental characteristics of the toner, and the like. Part by weight or less is preferred. The external additive may be added to each particle group before mixing the first toner particle group and the second toner particle group.

[Spheronization process]
In the toner manufacturing method of the present invention, as shown in FIG. 2, the spheronization step of Step S11 is provided between the second classification step of Step S8 and the mixing step of Step S9. Good. In the spheronization step, the second toner particle group is spheroidized. Examples of the spheroidizing method include a method of spheronizing with hot air and a method of spheronizing with a mechanical impact force. As the hot-air spheronizing device used for the spheronization treatment with hot air, a commercially available device can be used. For example, a surface reformer, Meteorebom (trade name, manufactured by Nippon Pneumatic Industry Co., Ltd.) Can be used. As the impact spheroidizing device used for the spheroidizing treatment by mechanical impact force, a commercially available device can be used, for example, Faculty (trade name, manufactured by Hosokawa Micron Corporation) or the like can be used.

  When the mixing process is completed, the process proceeds from step S9 to step S10, and the production of the toner of the present invention is completed.

  By using the toner production method as described above, the toner of the present invention is produced, which has uniform charging characteristics and development characteristics, can suppress deterioration in image quality due to toner scattering and fogging, and can stably obtain a high-quality image. can do.

  The toner particles produced as described above are responsible for functions such as powder flowability improvement, triboelectric chargeability improvement, heat resistance, long-term storage stability improvement, cleaning property improvement and photoreceptor surface wear property control. Additives may be mixed. Examples of the external additive include silica fine powder, titanium oxide fine powder, and alumina fine powder. One type of external additive can be used alone, or two or more types can be used in combination. The external additive is added in an amount of 0.1 to 100 parts by weight of the toner particles in consideration of the charge amount necessary for the toner, the effect of adding the external additive on the wear of the photoreceptor and the environmental characteristics of the toner. 1 to 10 parts by weight is preferred.

  The toner of the present invention thus produced can be used as it is as a one-component developer, or can be mixed with a carrier and used as a two-component developer.

  As the carrier, magnetic particles can be used. Specific examples of the particles having magnetism include metals such as iron, ferrite, and magnetite, and alloys of these metals with metals such as aluminum or lead. Among these, ferrite is preferable.

  Alternatively, a resin-coated carrier in which magnetic particles are coated with a resin, or a resin-dispersed carrier in which magnetic particles are dispersed in a resin may be used as the carrier. Although there is no restriction | limiting in particular as resin which coat | covers the particle | grains which have magnetism, For example, an olefin resin, a styrene resin, a styrene acrylic resin, a silicone resin, ester resin, a fluorine-containing polymer system resin, etc. are mentioned. Moreover, although it does not restrict | limit especially as resin used for a resin dispersion type carrier, For example, a styrene acrylic resin, a polyester-type resin, a fluorine resin, a phenol resin etc. are mentioned.

The shape of the carrier is preferably a spherical shape or a flat shape. The volume average particle diameter of the carrier is not particularly limited, but is preferably 10 μm to 100 μm, more preferably 20 μm to 50 μm, considering high image quality. Furthermore, the resistivity of the carrier is preferably 10 ⁸ Ω · cm or more, more preferably 10 ¹² Ω · cm or more. The carrier resistivity is determined by placing the carrier in a container having a cross-sectional area of 0.50 cm ² and tapping it, then applying a load of 1 kg / cm ² to the particles packed in the container and placing the load between the load and the bottom electrode. This is a value obtained by reading a current value when a voltage generating an electric field of 1000 V / cm is applied. When the resistivity is low, charges are injected into the carrier when a bias voltage is applied to the developing sleeve (developing roller), and the carrier particles easily adhere to the photosensitive drum. Further, breakdown of the bias voltage is likely to occur.

  The magnetization strength (maximum magnetization) of the carrier is preferably 10 emu / g to 60 emu / g, more preferably 15 emu / g to 40 emu / g. The magnetization strength depends on the magnetic flux density of the developing roller, but under the general magnetic flux density conditions of the developing roller, if it is less than 10 emu / g, the magnetic binding force does not work and causes carrier scattering. There is a fear. On the other hand, if the magnetization strength exceeds 60 emu / g, it becomes difficult to maintain a non-contact state with the photosensitive drum as the latent image carrier in the non-contact development in which the carrier spikes are too high. Further, in the contact development, there is a risk that a sweep is likely to appear in the toner image.

The use ratio of the toner and the carrier in the two-component developer is not particularly limited and can be appropriately selected according to the type of the toner and the carrier. However, the toner is used so that the carrier coverage with the toner is 40% or more and 80% or less. Use it. The resin-coated ^carrier: Taking an example (density of ^{5g / cm 2 ~8g / cm 2} ), the two-component in the developer, the toner is 30 wt% 2 wt% or more of the two-component developer total amount or less, preferably The toner may be used so that it is contained in an amount of 2 wt% or more and 20 wt% or less.

  By including the toner of the present invention and the carrier, the two-component developer of the present invention has uniform charging characteristics and development characteristics, suppresses deterioration in image quality due to toner scattering and fogging, and stably obtains high-quality images. Can do.

[Image forming apparatus]
FIG. 3 is a diagram schematically showing an example of the configuration of the image forming apparatus 1 of the present invention. The image forming apparatus 1 is a multifunction machine having both a copying function, a printer function, and a facsimile function, and forms a full-color image or a monochrome image on a recording medium according to transmitted image information. In other words, the image forming apparatus 1 has three types of printing modes, ie, a copier mode (copy mode), a printer mode, and a FAX mode, and an operation input from an operation unit (not shown), a personal computer, a portable terminal device, A print mode is selected by a control unit (not shown) in response to reception of a print job from an information recording storage medium and an external device using the memory device. As illustrated in FIG. 3, the image forming apparatus 1 includes a toner image forming unit 2, an intermediate transfer unit 3, a fixing unit 4, a recording medium supply unit 5, and a discharge unit 6. Each member constituting the toner image forming unit 2 and some members included in the intermediate transfer unit 3 are black (b), cyan (c), magenta (m), and yellow (y) included in the color image information. In order to correspond to the image information of each color, four each are provided. Hereinafter, each member provided by four according to each color is distinguished by adding alphabets b, c, m, and y, which represent each color, to the end of the reference symbol, and when referring generically, only the reference symbol is used.

  The toner image forming unit 2 includes a photosensitive drum 11, a charging unit 12, an exposure unit 13, a developing device 14, and a cleaning unit 15. The charging unit 12, the developing device 14, and the cleaning unit 15 are arranged around the photosensitive drum 11 in this order. The charging unit 12 is disposed below the developing device 14 and the cleaning unit 15 in the vertical direction.

  The photosensitive drum 11 is a latent image carrier that is supported by a driving unit (not shown) so as to be rotatable around an axis, and includes a conductive substrate (not shown) and a photosensitive layer formed on the surface of the conductive substrate. The conductive substrate can take various shapes, and examples thereof include a cylindrical shape, a columnar shape, and a thin film sheet shape. Among these, a cylindrical shape is more preferable. The conductive substrate is formed of a conductive material. As the conductive material, those commonly used in this field can be used. For example, metals such as aluminum, copper, brass, zinc, nickel, stainless steel, chromium, molybdenum, vanadium, indium, titanium, gold, platinum, etc. A conductive layer made of one or more of aluminum, aluminum alloy, tin oxide, gold, indium oxide and the like is formed on a film-like substrate such as two or more alloys, synthetic resin film, metal film, paper, etc. And a resin composition containing at least conductive particles or a conductive polymer. In addition, as a film-form base | substrate used for an electroconductive film, a synthetic resin film is preferable and a polyester film is especially preferable especially. Moreover, as a formation method of the electroconductive layer in an electroconductive film, vapor deposition, application | coating, etc. are preferable.

  The photosensitive layer is formed, for example, by laminating a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material. In that case, it is preferable to provide an undercoat layer between the conductive substrate and the charge generation layer or the charge transport layer. By providing an undercoat layer, the scratches and irregularities present on the surface of the conductive substrate are coated to smooth the surface of the photosensitive layer, preventing deterioration of the chargeability of the photosensitive layer during repeated use, at least at a low temperature or Advantages such as improving the charging characteristics of the photosensitive layer in a low humidity environment can be obtained. Further, it may be a laminated photosensitive layer having a three-layer structure excellent in durability provided with a protective layer for protecting the surface of the photosensitive layer as the uppermost layer.

  The charge generation layer is mainly composed of a charge generation material that generates a charge when irradiated with light, and contains a known binder resin, plasticizer, sensitizer and the like as necessary. As the charge generation material, those commonly used in this field can be used. Phthalocyanine pigments such as metal-free phthalocyanine, squalium dye, azulenium dye, thiapyrylium dye, carbazole skeleton, styryl stilbene skeleton, triphenylamine skeleton, dibenzothiophene skeleton, oxadiazole skeleton, fluorenone skeleton, bis stilbene skeleton, distyryl oxa And azo pigments having a diazole skeleton or a distyrylcarbazole skeleton. Among these, metal-free phthalocyanine pigments, oxotitanyl phthalocyanine pigments, bisazo pigments containing at least a fluorene ring or a fluorenone ring, bisazo pigments composed of aromatic amines, trisazo pigments, etc. have high charge generating ability and are highly sensitive. Suitable for obtaining layers. One type of charge generating material can be used alone, or two or more types can be used in combination. The content of the charge generation material is not particularly limited, but is preferably 5 parts by weight to 500 parts by weight, more preferably 10 parts by weight to 200 parts by weight with respect to 100 parts by weight of the binder resin in the charge generation layer. As the binder resin for the charge generation layer, those commonly used in this field can be used. For example, melamine resin, epoxy resin, silicone resin, polyurethane, acrylic resin, vinyl chloride-vinyl acetate copolymer resin, polycarbonate, phenoxy resin , Polyvinyl butyral, polyarylate, polyamide, polyester and the like. Binder resin can be used individually by 1 type, or can use 2 or more types together as needed.

  The charge generation layer generates charge by dissolving or dispersing appropriate amounts of charge generation materials, binder resins and, if necessary, plasticizers and sensitizers in an appropriate organic solvent capable of dissolving or dispersing these components. It can be formed by preparing a layer coating solution, applying this charge generation layer coating solution to the surface of the conductive substrate and drying. The layer thickness of the charge generation layer thus obtained is not particularly limited, but is preferably 0.05 μm to 5 μm, more preferably 0.1 μm to 2.5 μm.

  The charge transport layer laminated on the charge generation layer has a charge transport material having the ability to accept and transport the charge generated from the charge generation material and a binder resin for the charge transport layer as essential components. Contains known antioxidants, plasticizers, sensitizers, lubricants and the like. As the charge transport material, those commonly used in this field can be used, for example, poly-N-vinylcarbazole and its derivatives, poly-γ-carbazolylethyl glutamate and its derivatives, pyrene-formaldehyde condensate and its derivatives, Polyvinylpyrene, polyvinylphenanthrene, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, 9- (p-diethylaminostyryl) anthracene, 1,1-bis (4-dibenzylaminophenyl) propane, styrylanthracene, styrylpyrazoline, pyrazoline Derivatives, phenylhydrazones, hydrazone derivatives, triphenylamine compounds, tetraphenyldiamine compounds, triphenylmethane compounds, stilbene compounds, 3-methyl-2-benzothiazoli Electron donating substances such as azine compounds having a ring, fluorenone derivatives, dibenzothiophene derivatives, indenothiophene derivatives, phenanthrenequinone derivatives, indenopyridine derivatives, thioxanthone derivatives, benzo [c] cinnoline derivatives, phenazine oxide derivatives, tetra And electron accepting substances such as cyanoethylene, tetracyanoquinodimethane, promanyl, chloranil, and benzoquinone. The charge transport materials can be used alone or in combination of two or more. The content of the charge transport material is not particularly limited, but is preferably 10 to 300 parts by weight, more preferably 30 to 150 parts by weight, with respect to 100 parts by weight of the binder resin in the charge transport layer. As the binder resin for the charge transport layer, those commonly used in this field and capable of uniformly dispersing the charge transport material can be used. For example, polycarbonate, polyarylate, polyvinyl butyral, polyamide, polyester, polyketone, epoxy resin, polyurethane , Polyvinyl ketone, polystyrene, polyacrylamide, phenol resin, phenoxy resin, polysulfone resin, and copolymer resins thereof. Among these, in consideration of film formability, wear resistance of the resulting charge transport layer, electrical characteristics, etc., polycarbonate containing bisphenol Z as a monomer component (hereinafter referred to as “bisphenol Z type polycarbonate”), bisphenol Z type polycarbonate And a mixture of polycarbonate with other polycarbonates are preferred. Binder resin can be used individually by 1 type, or can use 2 or more types together.

  The charge transport layer preferably contains an antioxidant together with the charge transport material and the binder resin for the charge transport layer. As the antioxidant, those commonly used in this field can be used, and examples thereof include vitamin E, hydroquinone, hindered amine, hindered phenol, paraphenylenediamine, arylalkane and derivatives thereof, organic sulfur compounds, and organic phosphorus compounds. It is done. One antioxidant can be used alone, or two or more antioxidants can be used in combination. The content of the antioxidant is not particularly limited, but is 0.01% to 10% by weight, preferably 0.05% to 5% by weight, based on the total amount of components constituting the charge transport layer. The charge transport layer is dissolved or dispersed in a suitable organic solvent that can dissolve or disperse these components in an appropriate amount such as a charge transport material and a binder resin, and if necessary, an antioxidant, a plasticizer, and a sensitizer. The charge transport layer coating liquid is prepared, and the charge transport layer coating liquid is applied to the surface of the charge generation layer and dried. The thickness of the charge generation layer thus obtained is not particularly limited, but is preferably 10 μm to 50 μm, more preferably 15 μm to 40 μm. Note that a photosensitive layer in which a charge generation material and a charge transport material are present can be formed in one layer. In that case, the type, content, binder resin, and other additives of the charge generation material and the charge transport material may be the same as in the case of separately forming the charge generation layer and the charge transport layer.

  In this embodiment, the photosensitive drum 11 formed with the organic photosensitive layer using the charge generation material and the charge transport material as described above is used, but instead, an inorganic photosensitive layer using silicon or the like is formed. Can be used.

  The charging unit 12 faces the photosensitive drum 11 and is arranged so as to be separated from the surface of the photosensitive drum 11 along the longitudinal direction of the photosensitive drum 11 with a gap, and the surface of the photosensitive drum 11 has a predetermined polarity and Charge to potential. As the charging unit 12, a charging brush type charger, a charger type charger, a sawtooth type charger, an ion generator, or the like can be used. In the present embodiment, the charging unit 12 is provided so as to be separated from the surface of the photosensitive drum 11, but is not limited thereto. For example, a charging roller may be used as the charging unit 12 and the charging roller may be disposed so that the charging roller and the photosensitive drum 11 are in pressure contact with each other, or a contact charging type charger such as a charging brush or a magnetic brush may be used. Also good.

  The exposure unit 13 is arranged such that light of each color information emitted from the exposure unit 13 passes between the charging unit 12 and the developing device 14 and is irradiated on the surface of the photosensitive drum 11. The exposure unit 13 branches the image information into light of each color information of black, cyan, magenta, and yellow in the unit, and the surface of the photosensitive drum 11 charged to a uniform potential by the charging unit 12 is light of each color information. To form an electrostatic latent image on the surface. As the exposure unit 13, for example, a laser scanning unit including a laser irradiation unit and a plurality of reflecting mirrors can be used. In addition, a unit in which an LED array, a liquid crystal shutter, and a light source are appropriately combined may be used.

  FIG. 4 is a diagram schematically showing an example of the configuration of the developing device 14 of the present invention. As shown in FIG. 4, the developing device 14 includes a developing tank 20 and a toner hopper 21. The developing tank 20 is disposed so as to face the surface of the photosensitive drum 11, and is a container that supplies toner to the electrostatic latent image formed on the surface of the photosensitive drum 11 and develops it to form a visible toner image. It is a shaped member. The developing tank 20 accommodates toner in its internal space and accommodates a roller member such as a developing roller 20a, a supply roller 20b, and a stirring roller 20c, or a screw member, and rotatably supports it. An opening is formed in a side surface of the developing tank 20 facing the photosensitive drum 11, and a developing roller 20 a is rotatably provided at a position facing the photosensitive drum 11 through the opening. The developing roller 20 a is a roller-like member that supplies toner to the electrostatic latent image on the surface of the photoconductor 11 at the pressure contact portion or the closest portion with the photoconductor drum 11. When supplying the toner, a potential having a polarity opposite to the charging potential of the toner is applied to the surface of the developing roller 20a as a developing bias voltage (hereinafter simply referred to as “developing bias”). As a result, the toner on the surface of the developing roller 20a is smoothly supplied to the electrostatic latent image. Further, by changing the developing bias value, the amount of toner (toner adhesion amount) supplied to the electrostatic latent image can be controlled. The supply roller 20b is a roller-like member provided so as to be rotatable and facing the developing roller 20a, and supplies toner around the developing roller 20a. The agitation roller 20c is a roller-like member provided so as to be able to rotate and face the supply roller 20b, and feeds toner newly supplied from the toner hopper 21 into the developing tank 20 to the periphery of the supply roller 20b. The toner hopper 21 is provided so that a toner replenishing port (not shown) provided at the lower part in the vertical direction communicates with a toner receiving port (not shown) provided at the upper part in the vertical direction of the developing tank 20. The toner is replenished according to the toner consumption status of 20. Further, the toner hopper 21 may not be used and toner may be directly supplied from each color toner cartridge.

  After the toner image is transferred to the intermediate transfer belt 25, the cleaning unit 15 removes the toner remaining on the surface of the photosensitive drum 11, and cleans the surface of the photosensitive drum 11. For the cleaning unit 15, for example, a plate-like member such as a cleaning blade is used. In the image forming apparatus of the present invention, an organic photosensitive drum is mainly used as the photosensitive drum 11, and the surface of the organic photosensitive drum is mainly composed of a resin component. Deterioration of the surface is likely to proceed due to the chemical action of ozone generated by. However, the deteriorated surface portion is worn by receiving a rubbing action by the cleaning unit 15 and is gradually but surely removed. Therefore, the problem of surface deterioration due to ozone or the like is practically solved, and the charging potential by the charging operation can be stably maintained over a long period of time. Although the cleaning unit 15 is provided in this embodiment, the present invention is not limited to this, and the cleaning unit 15 may not be provided.

  According to the toner image forming unit 2, the surface of the photosensitive drum 11 that is uniformly charged by the charging unit 12 is irradiated with signal light corresponding to the image information from the exposure unit 13 to form an electrostatic latent image. Toner is supplied from the developing device 14 to form a toner image. After the toner image is transferred to the intermediate transfer belt 25, the toner remaining on the surface of the photosensitive drum 11 is removed by the cleaning unit 15. This series of toner image forming operations is repeatedly executed.

  The intermediate transfer unit 3 is disposed above the photosensitive drum 11, and includes an intermediate transfer belt 25, a driving roller 26, a driven roller 27, intermediate transfer rollers 28b, 28c, 28m, and 28y, a transfer belt cleaning unit 29, A transfer roller 30. The intermediate transfer belt 25 is an endless belt-like member that is stretched by a driving roller 26 and a driven roller 27 to form a loop-shaped movement path, and has a surface in contact with the photosensitive drum 11 in the direction of an arrow B. The photosensitive drums 11y, 11m, 11c, and 11b are driven to rotate in contact with each other. When the intermediate transfer belt 25 passes through the photosensitive drum 11 while being in contact with the photosensitive drum 11, an intermediate transfer roller 28 disposed on the surface of the photosensitive drum 11 is opposed to the photosensitive drum 11 via the intermediate transfer belt 25. A transfer bias having a polarity opposite to the charging polarity of the toner is applied, and the toner image formed on the surface of the photosensitive drum 11 is transferred onto the intermediate transfer belt 25. In the case of a full-color image, each color toner image formed on each of the photoconductive drums 11y, 11m, 11c, and 11b is sequentially transferred onto the intermediate transfer belt 25 to form a full-color toner image. The driving roller 26 is provided so as to be rotatable around its axis by driving means (not shown), and the intermediate transfer belt 25 is driven to rotate in the direction of arrow B by the rotational driving. The driven roller 27 is provided so as to be able to be driven and rotated by the rotational drive of the driving roller 26, and applies a certain tension to the intermediate transfer belt 25 so that the intermediate transfer belt 25 does not loosen. The intermediate transfer roller 28 is provided in pressure contact with the photosensitive drum 11 via the intermediate transfer belt 25 and capable of being driven to rotate about its axis by a driving unit (not shown). The intermediate transfer roller 28 is connected to a power source (not shown) for applying a transfer bias as described above, and has a function of transferring the toner image on the surface of the photosensitive drum 11 to the intermediate transfer belt 25. The transfer belt cleaning unit 29 is provided so as to face the driven roller 27 through the intermediate transfer belt 25 and to contact the outer peripheral surface of the intermediate transfer belt 25. The toner that adheres to the intermediate transfer belt 25 by contact with the photosensitive drum 11 and remains without being transferred to the recording medium causes the back surface of the recording medium to be contaminated. The toner on the surface is removed and collected. The transfer roller 30 is provided in pressure contact with the drive roller 26 via the intermediate transfer belt 25, and can be driven to rotate about an axis by a drive unit (not shown). At the pressure contact portion (transfer nip portion) between the transfer roller 30 and the drive roller 26, the toner image carried and conveyed by the intermediate transfer belt 25 is transferred to the recording medium fed from the recording medium supply means 5 described later. Is done. The recording medium carrying the toner image is fed to the fixing unit 4. According to the intermediate transfer unit 3, the toner image transferred from the photosensitive drum 11 to the intermediate transfer belt 25 at the pressure contact portion between the photosensitive drum 11 and the intermediate transfer roller 28 is moved in the direction of arrow B of the intermediate transfer belt 25. The sheet is conveyed to the transfer nip portion by rotation and transferred to a recording medium there.

  The fixing unit 4 is provided downstream of the transfer unit 3 in the conveyance direction of the recording medium, and includes a fixing roller 31 and a pressure roller 32. The fixing roller 31 is rotatably provided by a driving unit (not shown), and heats and melts the toner constituting the unfixed toner image carried on the recording medium to fix it on the recording medium. A heating unit (not shown) is provided inside the fixing roller 31. The heating unit heats the fixing roller 31 so that the surface of the fixing roller 31 reaches a predetermined temperature (heating temperature). For example, a heater or a halogen lamp can be used as the heating means. The heating means is controlled by a fixing condition control means described later. A temperature detection sensor is provided near the surface of the fixing roller 31 to detect the surface temperature of the fixing roller 31. The detection result by the temperature detection sensor is written in the storage unit of the control means described later, and the fixing condition control means controls the operation of the heating means based on the detection result. The pressure roller 32 is provided so as to be in pressure contact with the fixing roller 31 and is supported so as to be driven to rotate by the rotation driving of the fixing roller 31. The pressure roller 32 assists fixing of the toner image on the recording medium by pressing the toner and the recording medium when the toner is melted and fixed on the recording medium by the fixing roller 31. A pressure contact portion between the fixing roller 31 and the pressure roller 32 is a fixing nip portion. According to the fixing unit 4, the recording medium on which the toner image is transferred by the intermediate transfer unit 3 is sandwiched between the fixing roller 31 and the pressure roller 32, and the toner image is heated while passing through the fixing nip portion. By being pressed against the recording medium, the toner image is fixed on the recording medium and an image is formed.

  The recording medium supply unit 5 includes an automatic paper feed tray 35, a pickup roller 36, transport rollers 37 a, 37 b and 37 c, a registration roller 38, and a manual paper feed tray 39. The automatic paper feed tray 35 is a container-like member that is provided in the lower portion of the image forming apparatus in the vertical direction and stores a recording medium. Recording media include plain paper, color copy paper, overhead projector sheets, postcards, and the like. The pick-up roller 36 takes out the recording medium stored in the automatic paper feed tray 35 one by one and feeds it to the paper transport path S1. The conveyance rollers 37 a are a pair of roller members provided so as to be in pressure contact with each other, and convey the recording medium toward the registration rollers 38. The registration rollers 38 are a pair of roller members provided so as to be in pressure contact with each other, and the recording medium fed from the conveyance roller 37a is used to convey the toner image carried on the intermediate transfer belt 25 to the transfer nip portion. Synchronously, it is fed to the transfer nip. The manual paper feed tray 39 is a device for taking a recording medium into the image forming apparatus by manual operation. The recording medium taken from the manual paper feed tray 39 passes through the paper conveyance path S2 by the conveyance roller 37b, It is fed to the registration roller 38. According to the recording medium supply means 5, the toner image carried on the intermediate transfer belt 25 is conveyed to the transfer nip portion of the recording medium supplied one by one from the automatic paper feed tray 35 or the manual paper feed tray 39. In synchronism with this, the sheet is fed to the transfer nip portion.

  The discharge unit 6 includes a conveyance roller 37 c, a discharge roller 40, and a discharge tray 41. The conveyance roller 37 c is provided on the downstream side of the fixing nip portion in the sheet conveyance direction, and conveys the recording medium on which the image is fixed by the fixing unit 4 toward the discharge roller 40. The discharge roller 40 discharges the recording medium on which the image is fixed to a discharge tray 41 provided on the upper surface in the vertical direction of the image forming apparatus. The discharge tray 41 stores a recording medium on which an image is fixed.

The image forming apparatus includes a control unit (not shown). The control unit is provided, for example, in an upper part of the internal space of the image forming apparatus, and includes a storage unit, a calculation unit, and a control unit. In the storage unit of the control means, various setting values via an operation panel (not shown) arranged on the upper surface of the image forming apparatus, detection results from sensors (not shown) arranged at various locations inside the image forming apparatus, Image information and the like are input and stored. In addition, programs for executing various means are written. Examples of the various means include a recording medium determination unit, an adhesion amount control unit, and a fixing condition control unit. As the storage unit, those commonly used in this field can be used, and examples thereof include a read only memory (ROM), a random access memory (RAM), and a hard disk drive (HDD). As the external device, an electric / electronic device that can form or acquire image information and can be electrically connected to the image forming apparatus can be used. For example, a computer, a digital camera, a television receiver, a video recorder, DVD (digital versatile
disc) recorder, HDDVD (High-Definition digital versatile disc), Blu-ray disc recorder, facsimile device, portable terminal device, and the like. The arithmetic unit takes out various data (image formation command, detection result, image information, etc.) written in the storage unit and programs of various means, and performs various determinations. The control unit sends a control signal to the corresponding device according to the determination result of the calculation unit, and performs operation control. The control unit and the calculation unit include a processing circuit realized by a microcomputer, a microprocessor, or the like provided with a central processing unit (CPU). The control means includes a main power supply together with the processing circuit described above, and the power supply supplies power not only to the control means but also to each device in the image forming apparatus 1.

  The developing device 14 of the present invention can form a high-definition and high-resolution toner image on the photosensitive drum 11 by performing development using the two-component developer of the present invention. Further, the image forming apparatus 1 of the present invention is provided with the developing device 14 so that the charging characteristics and the developing characteristics become uniform, the deterioration of image quality due to toner scattering and fogging can be suppressed, and a high quality image can be stably formed. it can.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. However, the present invention is not particularly limited to these Examples as long as the gist thereof is not exceeded.

[Physical property measurement method]
Each physical property value in Examples and Comparative Examples was measured as shown below.

[Glass transition point of binder resin (Tg)]
Using a differential scanning calorimeter (trade name: DSC220, manufactured by Seiko Denshi Kogyo Co., Ltd.), according to Japanese Industrial Standard (JIS) K7121-1987, 1 g of a sample (binder resin) was heated at a heating rate of 10 ° C. per minute (10 ° C. / Min), and DSC curve was measured. Draw the endothermic peak corresponding to the glass transition of the obtained DSC curve at a point where the slope is maximum with respect to the straight line that extends the base line on the high temperature side to the low temperature side and the curve from the rising part of the peak to the vertex. The temperature at the intersection with the tangent was determined as the glass transition point (Tg).

[Softening point of binder resin (Tm)]
In a flow characteristic evaluation apparatus (trade name: Flow Tester CFT-100C, manufactured by Shimadzu Corporation), a load (10 kgf / cm ² (9.8 × 10 ⁵ Pa)) was applied and 1 g of a sample (binder resin) was extruded from the die. The sample was heated at a heating rate of 6 ° C./min (6 ° C./min), and the temperature at which half of the sample flowed out of the die was determined as the softening point. A die having a nozzle diameter of 1 mm and a length of 1 mm was used.

[Melting point of release agent]
Using a differential scanning calorimeter (trade name: DSC220, manufactured by Seiko Denshi Kogyo Co., Ltd.), 1 g of a sample (release agent) was increased from a temperature of 20 ° C. to 200 ° C. at a temperature rising rate of 10 ° C./min (10 ° C./min). The operation of heating and then rapidly cooling from 200 ° C. to 20 ° C. was repeated twice to obtain a DSC curve. Then, the temperature at the top of the endothermic peak corresponding to the melting of the DSC curve obtained by the second operation was determined as the melting point of the release agent.

[Volume average particle diameter ( _D50V ) and coefficient of variation (CV value)]
To 50 ml of electrolytic solution (trade name: ISOTON-II, manufactured by Beckman Coulter, Inc.), 20 mg of a sample (first or second toner particle group) and 1 ml of sodium alkyl ether sulfate (dispersant) are added, and ultrasonic dispersion is performed. A sample for measurement was prepared by dispersing for 3 minutes at an ultrasonic frequency of 20 kHz using a vessel (trade name: UH-50, manufactured by SMT Co., Ltd.).

About this measurement sample, using a particle size distribution measuring device (trade name: Multisizer 2, manufactured by Beckman Coulter, Inc.), the particle size was measured under the conditions of an aperture diameter of 100 μm and a measurement particle number of 50000 counts. The volume particle size distribution of the sample particles was determined from the measurement results, and the volume average particle size D _50V (μm) was calculated from the determined volume particle size distribution. Moreover, the standard deviation in volume particle size distribution was calculated | required, and the variation coefficient (CV value,%) was computed based on the above-mentioned Formula (2).

[Average charge]
5% by weight of the sample (first or second toner particle group) is mixed with 95% by weight of a ferrite core carrier having a volume average particle diameter of 45 μm, and the table is placed in a room temperature and humidity environment at a temperature of 25 ° C. and a relative humidity of 50%. After stirring for 30 minutes with a ball mill (manufactured by Tokyo Glass Instrument Co., Ltd.), the average charge amount of the sample (first or second toner particle group) was measured.

  The average charge amount was measured as follows using a charge amount measuring device (trade name: 210HS-2A, manufactured by Trek Japan Co., Ltd.). The mixture of ferrite core particles collected from the ball mill and the sample is put in a metal container having a conductive screen of 500 mesh at the bottom, and only the toner particles are sucked with a suction pressure of 250 mmHg by a suction machine. The average charge amount of the sample was determined from the weight difference between the weight of the mixture and the weight of the mixture after suction and the potential difference between the capacitor plates connected to the container.

[Judgment of compatibility and incompatibility of charge control agent to binder resin]
99% by weight of the binder resin and 1% by weight of the charge control agent were mixed for 10 minutes by a Henschel mixer (trade name: FM mixer, manufactured by Mitsui Mining Co., Ltd.). The obtained mixture was melt-kneaded with a twin-screw extrusion kneader (trade name: PCM-65, manufactured by Ikegai Co., Ltd.), then cooled to room temperature and solidified to obtain a melt-kneaded product. 10 mg of the obtained melt-kneaded material was fractionated, melted on a slide glass, and sandwiched between cover glasses and spread thinly with an optical microscope (trade name: VHX-600, manufactured by Keyence Corporation) at a magnification of 2000 times When the aggregate of the charge control agent observed is approximated to an ellipse, the charge control agent when the aggregate whose major axis is 1 μm or more is confirmed is incompatible with the binder resin. It was determined that the charge control agent in the case where the aggregate was not confirmed was compatible with the binder resin.

Example 1
[Production of First Toner Particle Group]
[First premixing step and first melt-kneading step]
Polyester (binder resin, trade name: Toughton TTR-5, manufactured by Kao Corporation, glass transition point (Tg): 60 ° C., softening point (Tm): 100 ° C.) 84% by weight (100 parts by weight), masterbatch ( CI Pigment Red 57: 1 (containing 40% by weight of colorant)) 12% by weight (14.3 parts by weight), carnauba wax (release agent, trade name: REFINED CARNAUBA WAX, manufactured by Hiroyuki Kato, Melting point: 83 ° C.) 3% by weight (3.6 parts by weight), organic bentonite (charge control agent, trade name: N4P, manufactured by Clariant Japan Co., Ltd.) 1.0% by weight (1.2 parts by weight) The toner material contained in was mixed for 10 minutes using a Henschel mixer (trade name: FM mixer, manufactured by Mitsui Mining Co., Ltd.). Then, the obtained toner raw material mixture was melt-kneaded with a twin-screw extrusion kneader (trade name: PCM-65, manufactured by Ikegai Co., Ltd.) to obtain a first melt-kneaded product.

[First grinding step]
After the first melt-kneaded product obtained in the first premixing step and the first melt-kneading step is cooled to room temperature and solidified, a cutting mill (trade name: VM-16, manufactured by Ryoko Sangyo Co., Ltd.) ). Subsequently, the coarsely pulverized product obtained by coarse pulverization was pulverized by a fluidized bed type jet pulverizer (trade name: Counterjet Mill, manufactured by Hosokawa Micron Corporation) to obtain a first pulverized product.

[First classification step]
From the pulverized product obtained in the pulverization step, the excessively pulverized toner particles were classified and removed using a rotary air classifier (manufactured by Hosokawa Micron Corporation) to produce a first toner particle group having a volume average particle size of 5.5 μm. .

[Production of Second Toner Particle Group]
[Second Premixing Step and Second Melt-Kneading Step]
Polyester (binder resin, trade name: Toughton TTR-5, manufactured by Kao Corporation, glass transition point (Tg): 60 ° C., softening point (Tm): 100 ° C.) 83.5% by weight (100 parts by weight), master Batch (containing CI Pigment Red 57: 1 (colorant): 40% by weight) 12% by weight (14.4 parts by weight), carnauba wax (release agent, trade name: REFIED CARNAUBA WAX, Hiroyuki Kato Co., Ltd.) Manufactured, melting point: 83 ° C.) 3% by weight (3.6 parts by weight), alkylsalicylic acid metal salt (charge control agent, trade name: BONTRON E-84, manufactured by Orient Chemical Co., Ltd.) 1.5% by weight (1.8 The toner raw material containing a part by weight was mixed with a Henschel mixer (trade name: FM mixer, manufactured by Mitsui Mining Co., Ltd.) for 10 minutes. The obtained toner raw material mixture was melt-kneaded with a twin-screw extrusion kneader (trade name: PCM-65, manufactured by Ikegai Co., Ltd.) to obtain a second melt-kneaded product.

[Second grinding step]
After the second melt-kneaded product obtained in the second premixing step and the second melt-kneading step is cooled to room temperature and solidified, a cutting mill (trade name: VM-16, Ryoko Sangyo Co., Ltd.) Coated). Subsequently, the coarsely pulverized product obtained by the coarse pulverization was pulverized by a fluidized bed type jet pulverizer (trade name: Counterjet Mill, manufactured by Hosokawa Micron Corporation) to obtain a second pulverized product.

[Second classification step]
In the second pulverized product obtained in the second pulverization step, the excessively pulverized toner particles are classified and removed by a rotary air classifier (manufactured by Hosokawa Micron Corporation), and the volume average particle diameter is 4.0 μm, the coefficient of variation ( A second toner particle group having a CV value of 25% was prepared.

[Production of toner]
[Mixing process]
After adding 1.2 parts by weight of silica fine particles (external additive, trade name: R972, manufactured by Nippon Aerosil Co., Ltd.) to 100 parts by weight of each of the first toner particle group and the second toner particle group, The toner of Example 1 was produced by mixing and stirring the first toner particle group and the second toner particle group so that the content of the second toner particle group was 10% by weight.

(Example 2)
In the first premixing step, 83% by weight of polyester (100 parts by weight), 12% by weight of masterbatch (14.5 parts by weight), 3% by weight of carnauba wax (3.6 parts by weight), and organic bentonite 2.0 A toner of Example 2 was produced in the same manner as in Example 1 except that wt% (2.4 parts by weight) was used. That is, the toner of Example 2 is different from the toner of Example 1 in the amount of organic bentonite (charge control agent) added in the first premixing step.

(Example 3)
In the first premixing step, 81.5% by weight (100 parts by weight) of polyester, 12% by weight (14.7 parts by weight) of master batch, 3% by weight of carnauba wax (3.7 parts by weight), and organic bentonite 3 5 wt% (4.3 wt parts), and in the second pre-mixing step, the polyester 84 wt% (100 wt parts), the masterbatch 12 wt% (14.3 wt parts), carnauba wax 3 A toner of Example 3 was produced in the same manner as in Example 1 except that 1% by weight (3.6 parts by weight) and 1.0% by weight (1.2 parts by weight) of an alkyl salicylic acid metal salt were used. That is, the toner of Example 3 includes the addition amount of the organic bentonite (charge control agent) added in the first premixing step and the alkyl salicylic acid metal salt (charge control agent) added in the second premixing step. The amount added is different from that of the toner of Example 1.

Example 4
In the first premixing step, 81% by weight (100 parts by weight) of polyester, 12% by weight (14.8 parts by weight) of masterbatch, 3% by weight of carnauba wax (3.7 parts by weight), 4.0 of organic bentonite % By weight (4.9 parts by weight), and in the second premixing step, 81% by weight (100 parts by weight) of polyester, 12% by weight (14.8 parts by weight) of masterbatch, 3% by weight of carnauba wax The toner of Example 4 was produced in the same manner as in Example 1, except that (3.7 parts by weight) and 4.0% by weight (4.9 parts by weight) of an alkyl salicylic acid metal salt were used. That is, the toner of Example 4 includes the amount of organic bentonite (charge control agent) added in the first premixing step and the alkyl salicylic acid metal salt (charge control agent) added in the second premixing step. The amount added is different from that of the toner of Example 1.

(Example 5)
In the first premixing step, 83% by weight of polyester (100 parts by weight), 12% by weight of masterbatch (14.5 parts by weight), 3% by weight of carnauba wax (3.6 parts by weight), and organic bentonite 2.0 % By weight (2.4 parts by weight), and in the second pre-mixing step, 84% by weight (100 parts by weight) of polyester, 12% by weight (14.3 parts by weight) of masterbatch, 3% by weight of carnauba wax A toner of Example 5 was produced in the same manner as in Example 1, except that (3.6 parts by weight) and 1.0% by weight (1.2 parts by weight) of an alkyl salicylic acid metal salt were used. That is, the toner of Example 5 includes the addition amount of organic bentonite (charge control agent) added in the first premixing step and the alkyl salicylic acid metal salt (charge control agent) added in the second premixing step. The amount added is different from that of the toner of Example 1.

(Example 6)
In the first classification step, a first toner particle group having a volume average particle size of 4.5 μm is prepared, and in the second premixing step, 83% by weight (100 parts by weight) of polyester and 12% by weight of the master batch (14.5 parts by weight), carnauba wax 3% by weight (3.6 parts by weight), and alkyl salicylic acid metal salt 2.0% by weight (2.4 parts by weight). A toner of Example 6 was produced in the same manner as in Example 1 except that a second toner particle group having an average particle size of 3.5 μm and a coefficient of variation (CV value) of 27% was produced. That is, the toner of Example 6 is composed of the volume average particle diameter of the first toner particle group produced in the first classification step and the alkyl salicylic acid metal salt (charge control agent) added in the second premixing step. The addition amount and the volume average particle size and coefficient of variation (CV value) of the second toner particle group produced in the second classification step are different from those of the toner of Example 1.

(Example 7)
In the first classification step, a first toner particle group having a volume average particle size of 6.5 μm is prepared, and in the second premixing step, 83% by weight (100 parts by weight) of polyester and 12% by weight of the master batch (14.5 parts by weight), carnauba wax 3% by weight (3.6 parts by weight), and alkyl salicylic acid metal salt 2.0% by weight (2.4 parts by weight). A toner of Example 7 was produced in the same manner as in Example 1 except that a second toner particle group having an average particle size of 3.5 μm and a coefficient of variation (CV value) of 27% was produced. That is, the toner of Example 7 is composed of the volume average particle diameter of the first toner particle group produced in the first classification step, and the alkyl salicylic acid metal salt (charge control agent) added in the second premixing step. The addition amount and the volume average particle size and coefficient of variation (CV value) of the second toner particle group produced in the second classification step are different from those of the toner of Example 1.

(Example 8)
In the first classification step, a first toner particle group having a volume average particle size of 6.5 μm is prepared, and in the second premixing step, 83% by weight (100 parts by weight) of polyester and 12% by weight of the master batch (14.5 parts by weight), carnauba wax 3% by weight (3.6 parts by weight), and alkyl salicylic acid metal salt 2.0% by weight (2.4 parts by weight). A toner of Example 8 was produced in the same manner as in Example 1 except that a second toner particle group having an average particle diameter of 4.5 μm and a coefficient of variation (CV value) of 25% was produced. That is, the toner of Example 8 is composed of the volume average particle diameter of the first toner particle group prepared in the first classification step, and the alkyl salicylic acid metal salt (charge control agent) added in the second premixing step. The addition amount and the volume average particle size and coefficient of variation (CV value) of the second toner particle group produced in the second classification step are different from those of the toner of Example 1.

Example 9
In the first premixing step, 83% by weight of polyester (100 parts by weight), 12% by weight of masterbatch (14.5 parts by weight), 3% by weight of carnauba wax (3.6 parts by weight), and organic bentonite 2.0 Except that the second toner particle group having a volume average particle size of 4.5 μm and a coefficient of variation (CV value) of 29% was prepared in the second classification step by using% by weight (2.4 parts by weight). The toner of Example 9 was produced in the same manner as Example 1. That is, in the toner of Example 9, the addition amount of the organic bentonite (charge control agent) added in the first premixing step and the coefficient of variation (CV) of the second toner particle group produced in the second classification step. Value) is different from the toner of Example 1.

(Example 10)
In the first premixing step, 83% by weight of polyester (100 parts by weight), 12% by weight of masterbatch (14.5 parts by weight), 3% by weight of carnauba wax (3.6 parts by weight), and organic bentonite 2.0 Example 10 was used in the same manner as in Example 1 except that 2% by weight (2.4 parts by weight) was used and the content of the second toner particle group was 5% by weight in the mixing step. A toner was produced. That is, the toner of Example 10 has the same amount of organic bentonite (charge control agent) added in the first premixing step and the content of the second toner particle group mixed in the mixing step as in Example 1. Different from toner.

Example 11
In the first premixing step, 83% by weight of polyester (100 parts by weight), 12% by weight of masterbatch (14.5 parts by weight), 3% by weight of carnauba wax (3.6 parts by weight), and organic bentonite 2.0 Example 11 was used in the same manner as in Example 1 except that 2% by weight (2.4 parts by weight) was used and the content of the second toner particle group was 20% by weight in the mixing step. A toner was produced. That is, the toner of Example 11 has the added amount of organic bentonite (charge control agent) added in the first premixing step and the content of the second toner particle group mixed in the mixing step. Different from toner.

Example 12
In the first premixing step, 84.9% by weight of polyester (100 parts by weight), 12% by weight of masterbatch (14.1 parts by weight), 3% by weight of carnauba wax (3.5 parts by weight), organic bentonite 0 0.1 wt% (0.1 wt%) and in the second premixing step, 84.5 wt% (100 wt%) polyester, 12 wt% (14.2 wt%) masterbatch, carnauba A toner of Example 12 was produced in the same manner as in Example 1, except that 3% by weight (3.6 parts by weight) of wax and 0.5% by weight (0.6 parts by weight) of metal alkylsalicylate were used. That is, the toner of Example 12 includes the addition amount of the organic bentonite (charge control agent) added in the first premixing step and the alkyl salicylic acid metal salt (charge control agent) added in the second premixing step. The amount added is different from that of the toner of Example 1.

(Example 13)
In the first premixing step, 78% by weight of polyester (100 parts by weight), 12% by weight of masterbatch (15.4 parts by weight), 3% by weight of carnauba wax (3.8 parts by weight), 7.0 of organic bentonite % By weight (9.0 parts by weight), and in the second premixing step, 81% by weight (100 parts by weight) of polyester, 12% by weight (14.8 parts by weight) of masterbatch, 3% by weight of carnauba wax A toner of Example 13 was produced in the same manner as in Example 1, except that (3.7 parts by weight) and 4.0% by weight (4.9 parts by weight) of an alkyl salicylic acid metal salt were used. That is, the toner of Example 13 includes the addition amount of organic bentonite (charge control agent) added in the first premixing step and the alkyl salicylic acid metal salt (charge control agent) added in the second premixing step. The amount added is different from that of the toner of Example 1.

(Example 14)
In the first premixing step, 81% by weight (100 parts by weight) of polyester, 12% by weight (14.8 parts by weight) of masterbatch, 3% by weight of carnauba wax (3.7 parts by weight), 4.0 of organic bentonite % By weight (4.9 parts by weight), and in the second premixing step, 79% by weight (100 parts by weight) of polyester, 12% by weight (15.2 parts by weight) of masterbatch, 3% by weight of carnauba wax A toner of Example 14 was produced in the same manner as in Example 1 except that (3.8 parts by weight) and 6.0% by weight (7.6 parts by weight) of an alkyl salicylic acid metal salt were used. That is, the toner of Example 14 includes the addition amount of organic bentonite (charge control agent) added in the first premixing step and the alkyl salicylic acid metal salt (charge control agent) added in the second premixing step. The amount added is different from that of the toner of Example 1.

(Example 15)
In the first premixing step, 84.5% by weight (100 parts by weight) of polyester, 12% by weight (14.2 parts by weight) of masterbatch, 3% by weight (3.6 parts by weight) of carnauba wax, 0% of organic bentonite A toner of Example 15 was produced in the same manner as in Example 1 except that 0.5% by weight (0.6 parts by weight) was used. That is, the toner of Example 15 is different from the toner of Example 1 in the amount of organic bentonite (charge control agent) added in the first premixing step.

(Example 16)
In the first classification step, a first toner particle group having a volume average particle size of 6.5 μm is prepared, and in the second premixing step, 84% by weight (100 parts by weight) of polyester and 12% by weight of the master batch (14.3 parts by weight), carnauba wax 3% by weight (3.6 parts by weight), and alkyl salicylic acid metal salt 1.0% by weight (1.2 parts by weight). A toner of Example 16 was produced in the same manner as in Example 1 except that a second toner particle group having an average particle diameter of 6.0 μm and a coefficient of variation (CV value) of 25% was produced. That is, the toner of Example 16 is composed of the volume average particle diameter of the first toner particle group produced in the first classification step, and the alkyl salicylic acid metal salt (charge control agent) added in the second premixing step. The addition amount and the volume average particle size of the second toner particle group produced in the second classification step are different from those of the toner of Example 1.

(Example 17)
In the first classification step, a first toner particle group having a volume average particle size of 6.5 μm is prepared, and in the second classification step, the volume average particle size is 4.0 μm and the coefficient of variation (CV value) is 32%. The toner of Example 17 was produced in the same manner as in Example 1 except that the second toner particle group was produced. That is, in the toner of Example 17, the volume average particle diameter of the first toner particle group produced in the first classification step and the coefficient of variation (CV) of the second toner particle group produced in the second classification step. Value) is different from the toner of Example 1.

(Example 18)
In the first premixing step, 78% by weight of polyester (100 parts by weight), 12% by weight of masterbatch (15.4 parts by weight), 3% by weight of carnauba wax (3.8 parts by weight), 7.0 of organic bentonite In the second premixing step, 79% by weight (100 parts by weight) of polyester, 12% by weight (15.2 parts by weight) of masterbatch, and 3% by weight of carnauba wax were used. A toner of Example 18 was produced in the same manner as in Example 1 except that (3.8 parts by weight) and 6.0% by weight (7.6 parts by weight) of an alkyl salicylic acid metal salt were used. That is, the toner of Example 18 includes the addition amount of the organic bentonite (charge control agent) added in the first premixing step and the alkyl salicylic acid metal salt (charge control agent) added in the second premixing step. The amount added is different from that of the toner of Example 1.

Example 19
In the second premixing step, 84.9% (100 parts by weight) polyester, 12% (14.1 parts by weight) masterbatch, 3% by weight (3.5 parts by weight) carnauba wax, metal alkylsalicylate A toner of Example 19 was produced in the same manner as in Example 1, except that 0.1% by weight (0.1 part by weight) of salt was used. That is, the toner of Example 19 is different from the toner of Example 1 in the amount of addition of the alkyl salicylic acid metal salt (charge control agent) added in the second premixing step.

(Example 20)
In the first classification step, a first toner particle group having a volume average particle size of 8.0 μm is prepared, and in the second premixing step, 84% by weight (100 parts by weight) of polyester and 12% by weight of the master batch (14.3 parts by weight), carnauba wax 3% by weight (3.6 parts by weight), and alkyl salicylic acid metal salt 1.0% by weight (1.2 parts by weight). A toner of Example 20 was produced in the same manner as in Example 1 except that a second toner particle group having an average particle diameter of 6.0 μm and a coefficient of variation (CV value) of 25% was produced. That is, the toner of Example 20 is composed of the volume average particle diameter of the first toner particle group prepared in the first classification step, and the alkyl salicylic acid metal salt (charge control agent) added in the second premixing step. The addition amount and the volume average particle size of the second toner particle group produced in the second classification step are different from those of the toner of Example 1.

(Example 21)
The toner of Example 21 was produced in the same manner as in Example 1, except that the first toner particle group having a volume average particle diameter of 8.0 μm was produced in the first classification step. That is, the toner of Example 21 is different from the toner of Example 1 in the volume average particle size of the first toner particle group produced in the first classification step.

(Example 22)
In the first premixing step, 83% by weight of polyester (100 parts by weight), 12% by weight of masterbatch (14.5 parts by weight), 3% by weight of carnauba wax (3.6 parts by weight), and organic bentonite 2.0 The first toner particle group having a volume average particle size of 3.5 μm is prepared in the first classification step using the weight% (2.4 parts by weight), and the polyester 83 is used in the second premixing step. Wt% (100 parts by weight), masterbatch 12% by weight (14.5 parts by weight), carnauba wax 3% by weight (3.6 parts by weight), alkylsalicylic acid metal salt 2.0% by weight (2.4 parts by weight) In the same manner as in Example 1, except that a second toner particle group having a volume average particle size of 3.0 μm and a coefficient of variation (CV value) of 29% was produced in the second classification step. 22 toners were produced. That is, in the toner of Example 22, the addition amount of the organic bentonite (charge control agent) added in the first premixing step, the volume average particle size of the first toner particle group prepared in the first classification step. The addition amount of the alkyl salicylic acid metal salt (charge control agent) added in the second premixing step, and the volume average particle size and coefficient of variation (CV value) of the second toner particle group prepared in the second classification step ) Is different from the toner of Example 1.

(Example 23)
A toner of Example 23 was produced in the same manner as in Example 1, except that the content of the second toner particle group was 1% by weight in the mixing step. That is, the toner of Example 23 is different from the toner of Example 1 in the content of the second toner particle group mixed in the mixing step.

(Example 24)
A toner of Example 24 was produced in the same manner as in Example 1, except that the content of the second toner particle group was 25% by weight in the mixing step. That is, the toner of Example 24 is different from the toner of Example 1 in the content of the second toner particle group mixed in the mixing step.

(Comparative Example 1)
In the second pre-mixing step, 81% by weight of polyester (100 parts by weight), 12% by weight (14.8 parts by weight) of master batch, 3% by weight of carnauba wax (3.7 parts by weight), 4.0% of organic bentonite A toner of Comparative Example 1 was produced in the same manner as in Example 1 except that% by weight (4.9 parts by weight) was used. That is, the toner of Comparative Example 1 is different from the toner of the example in that the first toner particle group and the second toner particle group contain a charge control agent that is incompatible with the binder resin.

(Comparative Example 2)
In the first premixing step, an alkyl salicylic acid metal salt is used as a charge control agent, and in the second premixing step, 81% by weight (100 parts by weight) of polyester and 12% by weight (14.8% by weight) of the master batch. Part), carnauba wax 3% by weight (3.7 parts by weight), and alkylsalicylic acid metal salt 4.0% by weight (4.9 parts by weight). Manufactured. That is, the toner of Comparative Example 2 is different from the toner of the example in that the first toner particle group and the second toner particle group contain a charge control agent that is compatible with the binder resin.

(Comparative Example 3)
In the first premixing step, 83.5% by weight (100 parts by weight) of polyester, 12% by weight (14.4 parts by weight) of masterbatch, 3% by weight of carnauba wax (3.6 parts by weight), metal alkylsalicylate In the second pre-mixing step, 81.5% by weight (100 parts by weight) of polyester and 12% by weight (14.7 parts by weight) of the master batch were used. The toner of Comparative Example 3 was produced in the same manner as in Example 1 except that 3% by weight (3.7 parts by weight) of carnauba wax and 3.5% by weight (4.3 parts by weight) of organic bentonite were used. That is, in the toner of Comparative Example 3, the first toner particle group contains a charge control agent that is compatible with the binder resin, and the second toner particle group has an incompatible charge with respect to the binder resin. It differs from the toner of the example in that it contains a control agent.

  In the toner production by the kneading and pulverization method, it is difficult to produce a toner having a volume average particle size of less than 3 μm. Therefore, a toner having a volume average particle size of less than 3 μm was not produced.

In the toners of Examples 1 to 24 and Comparative Examples 1 to 3, the type and content of the charge control agent mixed in the first and second toner particle groups, the particle size distribution of each toner particle group, the second in the toner Table 1 shows the content of the toner particle group and the absolute value of the difference in the average charge amount of each toner particle group. In Table 1, the average amount of charge of the first toner particles and Q _A, an average charge amount of the second toner particles was Q _B.

[Manufacture of two-component developer]
A ferrite core carrier having a volume average particle diameter of 45 μm was used as the carrier, and a V-type mixer / mixer (so that the toner coverages of Examples 1 to 24 and Comparative Examples 1 to 3 were 60% with respect to this carrier ( (Trade name: V-5, manufactured by Tokuju Kogyo Co., Ltd.), toner and carrier were mixed for 20 minutes to produce a two-component developer.

[Evaluation]
Using the two-component developers each containing the toners of Examples 1 to 24 and Comparative Examples 1 to 3, the charge amount distribution, toner scattering, fogging, cleaning properties, transfer efficiency and image reproducibility were evaluated by the following methods. . Table 2 shows the results of each evaluation and the results of comprehensive evaluation.

[Charge amount distribution]
5% by weight of toner is mixed with 95% by weight of a ferrite core carrier having a volume average particle diameter of 45 μm and 30% by a table-top ball mill (manufactured by Tokyo Glass Instruments Co., Ltd.) in a normal temperature and humidity environment of 25 ° C. and 50% relative humidity After stirring for a minute, the coefficient of variation CVq serving as an index for evaluating the charge amount distribution was determined as follows using a charge amount distribution measuring device (E-Spart: manufactured by Hosokawa Micron Corporation). First, a mixture of ferrite core particles and toner collected from the ball mill is attached to a magnetic ring, and nitrogen gas is blown to separate and drop the toner particles to a measuring section, and the particle size and charge amount of each particle are measured. It was. Next, the number of toner particles (n): 6000, the charge amount x of toner particles (= q / m: q indicates the charge amount per toner particle, m indicates the mass per toner particle), and the average charge amount The coefficient of variation (CVq value) was calculated from M (= x / n) and the standard deviation σ (= √ [{nΣx2− (Σx) 2} / n2]) in the charge amount distribution based on the following formula (3). Then, with respect to the obtained coefficient of variation (CVq value), the charge amount distribution was evaluated based on the following evaluation criteria.
CVq value (%) = (σ / M) × 100 (3)
A: Very good. CVq value is less than 45%.
○: Good. The CVq value is 45% or more and less than 55%.
Δ: No problem in actual use. The CVq value is 55% or more and less than 65%.
X: Defect. The CVq value is 65% or more.

[Toner scattering]
The developer tank of a commercial copier (trade name: MX-2300G, manufactured by Sharp Corporation) is filled with a two-component developer, and the developer tank is idled for 3 hours in a high-temperature and high-humidity environment at a temperature of 35 ° C. and a relative humidity of 80%. It was. The difference in toner concentration in the two-component developer before and after the start of idling was determined, and the toner scattering was evaluated based on the following evaluation criteria for the obtained difference value.
A: Very good. The difference in toner density is less than 0.5% with respect to the toner density before starting idling.
○: Good. The difference in toner density is 0.5% or more and less than 1% with respect to the toner density before starting idling.
Δ: No problem in actual use. The difference in toner density is 1% or more and less than 1.5% with respect to the toner density before starting idling.
X: Defect. The difference in toner density is 1.5% or more with respect to the toner density before starting idling.

[Cover]
A commercial copier (trade name: MX-2300G, manufactured by Sharp Corporation) is filled with a two-component developer and adjusted so that the toner adhesion amount on the photosensitive drum is 0.4 mg / cm ^2. An image including a portion and a non-image portion was formed. The toner adhering to the non-image area in the formed image was collected with an adhesive tape, and the image density (ID) was measured with a colorimetric color difference meter (trade name: X-Rite, manufactured by X-Rite). The evaluation criteria for fogging are as follows.
A: Very good. ID is less than 0.05.
○: Good. ID is 0.05 or more and less than 0.1.
Δ: No problem in actual use. ID is 0.1 or more and less than 0.2%.
X: Defect. ID is 0.2% or more.

[Cleanability]
The cleaning blade pressure, which is the pressure with which the cleaning blade provided in the cleaning unit provided in a commercial copier (trade name: MX-2300G, manufactured by Sharp Corporation) comes into contact with the photosensitive drum, is 25 gf / cm (2.45) at the initial linear pressure. × 10 ⁻¹ N / cm). Each copier is filled with a two-component developer, and a character test chart made by Sharp Corporation is formed on 100,000 sheets of recording paper in a normal temperature and humidity environment at a temperature of 25 ° C. and a relative humidity of 50%. went.

The cleaning performance is determined by visually checking the formed image at each stage before image formation (initial stage), after printing 5,000 sheets (5K sheets), and after printing 10,000 sheets (10K sheets). The sharpness of the boundary between the image area and the non-image area, the presence or absence of black streaks formed due to toner leakage in the rotation direction of the photosensitive drum, and the fogging amount Wk is obtained by a measuring instrument to be described later, and the cleaning property Evaluated. The fogging amount Wk of the formed image was determined as follows by measuring the reflection density using a Z-Σ90 COLOREASURING SYSTEM manufactured by Nippon Denshoku Industries Co., Ltd. First, the reflection average density Wr of the recording paper before image formation was measured. Next, the reflection density at various points on the white background of the recording paper after image formation was measured. The value determined by the following formula (4) from the reflection density Ws of the portion with the highest fog, that is, the white background portion and the darkest portion, and the Wr is defined as the fog amount Wk (%). did. The evaluation criteria are as follows.
Wk = 100 × (Ws−Wr) / Wr (4)
A: Very good. There is no black streak with good clarity. The fogging amount Wk is less than 3%.
○: Good. There is no black streak with good clarity. The fogging amount Wk is 3% or more and less than 5%.
Δ: No problem in actual use. The level of sharpness is not a problem in actual use, and the length of black streaks is 2.0 mm or less and 5 or less. The fogging amount Wk is 5% or more and less than 10%.
×: Unusable. There is a problem in actual use of sharpness. The length of the black streaks exceeds 2.0 mm, or at least one of the black streaks is 6 or more. The fogging amount Wk is 10% or more.

[Transfer efficiency]
The transfer efficiency is a ratio of the toner transferred from the surface of the photosensitive drum to the intermediate transfer belt in the primary transfer, and the ratio of the toner amount existing on the photosensitive drum before the transfer is calculated as 100%. The amount of toner present on the photosensitive drum before transfer is obtained by sucking the amount of toner present on the photosensitive drum before transfer using a charge amount measuring device (trade name: 210HS-2A, manufactured by Trek Japan Co., Ltd.) It was obtained by measuring the amount of this sucked toner. The amount of toner transferred to the intermediate transfer belt was also obtained in the same manner. The evaluation criteria are as follows.
A: Transfer efficiency is 95% or more.
○: Transfer efficiency is 90% or more and less than 95%.
Δ: Transfer efficiency is 85% or more and less than 90%.
X: Transfer efficiency is less than 85%.

[Image reproducibility]
An original image of a fine line having a line width of exactly 100 μm under the condition that a halftone image having an image density of 0.3 and a diameter of 5 mm can be copied with an image density of 0.3 to 0.5 by the copying machine. The original to be formed was copied, and the obtained copy image was used as a measurement sample. The line width of the thin line formed on the measurement sample by the indicator was measured from a monitor image obtained by enlarging the measurement sample 100 times using a particle analyzer (trade name: Luzex 450, manufactured by Nireco Corporation). Since the thin line has irregularities and the line width varies depending on the measurement position, the line width is measured at a plurality of measurement positions and an average value is obtained, and this line width is taken as the line width of the measurement sample. The line width of the measurement sample was divided by the original line width of 100 μm, and the obtained value was multiplied by 100 to obtain a fine line reproducibility value. The closer the value of the fine line reproducibility is to 100, the better the fine line reproducibility and the better the image reproducibility. The evaluation criteria are as follows. The image density indicates an optical reflection density measured by a reflection densitometer (trade name: RD-918, manufactured by Macbeth Co.).
A: Fine line reproducibility is 100 or more and less than 105.
A: Fine line reproducibility value is 105 or more and less than 115.
(Triangle | delta): The value of fine line reproducibility is 115-125.
X: The fine line reproducibility value is 125 or more.

[Comprehensive evaluation]
The evaluation criteria for comprehensive evaluation are as follows.
A: Very good. There are no Δ and × in each evaluation result.
○: Good. Each evaluation result has no x and Δ is 1 or more and 3 or less.
Δ: No problem in actual use. Each evaluation result has no x and Δ is 4 or more.
X: Defect. There is at least one x in each evaluation result.

  From the results shown in Table 2, the two-component developer using the toners of Examples 1 to 24 in the present invention is superior to the two-component developers of Comparative Examples 1 to 3 as follows. Is clear.

  In the two-component developer using the toners of Examples 1 to 24, N4P which is a charge control agent incompatible with the binder resin is used for the first toner particle group, and the second toner particle group is used. In addition, since E-84, a charge control agent that is compatible with the binder resin, was used, the charge amount distribution was stable, toner scattering and fogging were small, cleaning properties and transfer efficiency were good, and high definition. A good image could be formed.

  On the other hand, the two-component developer using the toner of Comparative Example 1 uses N4P, which is a charge control agent that is incompatible with the binder resin, for the second toner particle group. The quantity distribution became unstable, causing toner scattering and fogging.

  In addition, the two-component developer using the toner of Comparative Example 2 uses E-84, which is a charge control agent compatible with the binder resin, in the first toner particle group, so that the charge in a large particle size toner is charged. The amount decreased and the charge amount distribution was unstable. As a result, fogging was observed and the transfer efficiency deteriorated.

  Further, the two-component developer using the toner of Comparative Example 3 uses E-84, which is a charge control agent compatible with the binder resin, as the first toner particle group, and the second toner particle group. In addition, since N4P, which is a charge control agent incompatible with the binder resin, was used, the charge amount decreased and the charge amount distribution became unstable. As a result, toner scattering and fogging were often observed, and cleaning properties and transfer efficiency were also deteriorated.

  In this embodiment, as a toner for electrophotography, C.I. I. Although magenta toner containing CI Pigment Red 57: 1 is exemplified, the present invention is not limited to this, and other toners containing the various colorants exemplified above may be used in place of the above colorants. This embodiment can be implemented.

It is a flowchart which shows an example of the procedure of the manufacturing method of the toner of this invention. It is a flowchart which shows an example of the procedure of the manufacturing method of the toner of this invention. 1 is a diagram schematically illustrating an example of a configuration of an image forming apparatus of the present invention. It is a figure which shows typically an example of a structure of the developing device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Toner image forming means 3 Intermediate transfer means 4 Fixing means 5 Recording medium supply means 6 Ejecting means 11 Photosensitive drum 12 Charging means 13 Exposure unit 14 Developing device 15 Cleaning unit 20 Developing tank 21 Toner hopper 25 Intermediate transfer belt 26 Drive roller 27 Follower roller 28 Intermediate transfer roller 29 Transfer belt cleaning unit 30 Transfer roller 31 Fixing roller 32 Pressure roller 35 Automatic paper feed tray 36 Pickup roller 37 Transport roller 38 Registration roller 39 Manual feed tray 40 Discharge roller 41 Discharge tray

Claims (11)

A first toner particle group containing at least a binder resin, a colorant, and a charge control agent incompatible with the binder resin;
And a second toner particle group that includes at least a binder resin, a colorant, and a charge control agent that is compatible with the binder resin and has a volume average particle diameter smaller than that of the first toner particle group. Toner characterized by the above. The average amount of charge of the first toner particles and Q _A, when the average charge amount of the second toner particles was Q _B, Q _A and Q _B is a satisfying the following formula (1) The toner according to claim 1.
| Q _A −Q _B | <5 (μC / g) (1)   The toner according to claim 1, wherein the binder resin contains a polyester resin. A method for producing the toner according to any one of claims 1 to 3,
A first premixing step of preparing a first mixture by mixing at least a binder resin, a colorant, and a charge control agent incompatible with the binder resin;
A first melt-kneading step of producing a first melt-kneaded product by melt-kneading the first mixture;
A first pulverization step of pulverizing the first melt-kneaded product to produce a first pulverized product;
A first classification step of classifying the first pulverized product to produce a first toner particle group;
A second premixing step of preparing a second mixture by mixing a charge control agent compatible with at least the binder resin, the colorant, and the binder resin;
A second melt-kneading step of melt-kneading the second mixture to produce a second melt-kneaded product;
A second pulverization step of pulverizing the second melt-kneaded product to produce a second pulverized product;
A second classification step of classifying the second pulverized product to produce a second toner particle group having a volume average particle size smaller than that of the first toner particle group;
A method for producing toner, comprising: a mixing step of mixing the first toner particle group and the second toner particle group.   In the first premixing step, a charge control agent that is incompatible with the binder resin is mixed so as to be 0.5 wt% or more and 5 wt% or less with respect to 100 wt% of the first toner particle group. In the second premixing step, the charge control agent that is compatible with the binder resin is 0.5 wt% to 5 wt% with respect to 100 wt% of the second toner particle group. The toner production method according to claim 4, wherein the toner is mixed.   6. The volume average particle size of the first toner particle group is 4 μm or more and 7 μm or less, and the volume average particle size of the second toner particle group is 3 μm or more and 5 μm or less. Toner manufacturing method.   The toner production method according to claim 4, wherein a variation coefficient of the particle size distribution of the second toner particle group is 30% or less.   The first toner particle group and the second toner particle group are mixed so that the content of the second toner particle group is 2% by weight or more and 20% by weight or less in the mixing step. The method for producing a toner according to any one of 4 to 7.   A two-component developer comprising the toner according to any one of claims 1 to 3 and a carrier.   A developing device that performs development using the two-component developer according to claim 9.   An image forming apparatus comprising the developing device according to claim 10.

Images