JP4489109B2 - Toner and production method thereof, two-component developer - Google Patents

Description

The present invention is an image forming apparatus such as an electrophotographic method or an electrostatic printing method, toners and manufacturing method thereof used for development of the latent image, relates to two-component developer.

  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.

  An image forming apparatus that forms an image using an electrophotographic system includes a photoconductor, a charging unit, an exposure unit, a developing unit, a transfer unit, and a fixing unit. The charging unit charges the surface of the photoreceptor. The exposure unit irradiates the charged photosensitive member surface with signal light to form an electrostatic latent image corresponding to the image information. The developing unit supplies toner for electrophotography (hereinafter simply referred to as “toner”) in the developer to the electrostatic latent image formed on the surface of the photoreceptor to form a toner image. The transfer unit transfers the toner image formed on the surface of the photoreceptor to a recording medium. The fixing unit fixes the transferred toner image on the recording medium. The cleaning means is, for example, a cleaning blade, and cleans the surface of the photoconductor by scraping the toner remaining on the surface of the photoconductor after the toner image is transferred with the blade. In such an image forming apparatus, an electrostatic latent image is developed using a one-component developer containing toner or a two-component developer containing toner and a carrier as a developer to form an image. The toner used here is resin particles granulated by dispersing a colorant, a wax as a release agent, etc. in a binder resin as a matrix.

  An image forming apparatus using an electrophotographic system can form an image with good image quality at a high speed and at a low cost. Therefore, the image forming apparatus is used in copying machines, printers, facsimiles, and the like, and has recently been remarkably popular. As a result, the demands on image forming apparatuses have become more severe. In particular, the emphasis is on high definition, high resolution, stable image quality, and high image forming speed of an image formed by the image forming apparatus. In order to achieve these, studies from both the image forming process and the developer are indispensable.

  For the purpose of improving the image quality of the image, it is important from the viewpoint of the developer that it is important to prevent image density reduction and image fogging. In addition, it is a problem to be solved to prevent filming in which toner components adhere to the photosensitive member. In order to solve such problems, toners aimed at improving cleaning properties have been proposed (for example, see Patent Documents 1 to 4).

  Patent Document 1 discloses a toner in which the toner powder is a mixture of a toner powder and a fine powder having an average particle size smaller than the average particle size of the toner powder, and the fine powder is attached to the toner powder. In Patent Document 1, the fine powder contains one or more monomers selected from acrylic ester monomers, methacrylic ester monomers, styrene monomers, nitrogen-containing addition polymerizable monomers, and polymerizable unsaturated carboxylic acid monomers in an aqueous medium. A polymer fine powder having an average particle diameter of 0.05 to 5 μm, which is obtained by non-emulsifier emulsion polymerization obtained by polymerization with a persulfate-based initiator or by using a water-soluble polymer instead of an emulsifier. is there.

  Patent Document 2 discloses a color toner obtained by fixing resin fine powder on the surface of a spherical toner particle powder having an average particle diameter of 2 to 8 μm. The fine resin powder has a glass transition point higher than that of the binder resin contained in the toner particle powder, and has an average particle size of 50 to 150 μm.

  Patent Document 3 discloses a toner obtained by immobilizing organic fine particles having a hardness higher than that of a binder resin of toner particles on the surface of toner particles and then externally adding post-treated fine particles. In Patent Document 3, the organic resin fine particles are added in an amount of 0.5 to 3% by weight based on the toner particles, the average primary particle diameter is 0.01 to 2 μm, and the Rockwell hardness is a binder resin. 10 or more larger than the Rockwell hardness.

  Patent Document 4 discloses a toner in which chargeable resin particles are fixed to the surface of non-spherical particles containing a colorant and a binder resin. In Patent Document 4, the surface coverage of the non-spherical particles by the chargeable resin particles is 5 to 50%. In addition, the chargeable resin particles are fixed to the convex surface of the non-spherical particles while being fused to each other.

  According to the toners disclosed in Patent Documents 1 to 4, organic fine particles are attached to, fixed to, or fused to toner particles, thereby improving toner cleaning properties and preventing filming. be able to. However, the toners of Patent Documents 1 to 4 have the following problems to be solved.

  The toner disclosed in Patent Document 1 is in a state where the fine powder is adhered to the toner particles by mixing the fine powder with the toner particles. Therefore, the adhesion force of fine powder to toner particles is very small. When used for a long time, fine particles are detached from the toner particles, for example, by stirring in the developing container, and the effect of improving the cleaning property by mixing the fine particles is maintained for a long time. Difficult to do.

  The toners disclosed in Patent Documents 2 and 3 are, for example, a resin fine powder or organic resin fine particles (hereinafter referred to as “resin fine particles”) by a mechanical impact force of a general mixer, a hybridization system, or the like. ) Is buried and fixed. Although the toners disclosed in Patent Documents 2 and 3 have greater adhesion to the toner particles of the resin fine particles than the toner disclosed in Patent Document 1, the resin fine particles are converted into toner particles by stirring in the developing container. Cannot be prevented sufficiently, and the problem that the cleaning property is deteriorated by long-term use cannot be solved.

  Since the toner disclosed in Patent Document 4 is fixed in a state where the chargeable resin particles are fused to the non-spherical particles, the adhesion force of the chargeable resin particles to the non-spherical particles can be sufficiently increased. The surface coverage of the non-spherical particles by the conductive resin particles is 5 to 50%, and since the chargeable resin particles are fixed only on the convex surface of the non-spherical particles, the low melting point component contained in the non-spherical particles is The problem of leaching and toner aggregation occurs.

  In recent years, with the trend toward higher process speed and energy saving, lowering the toner fixing temperature is desired. As a low-temperature fixing toner, a method of adding a low-melting crystalline polyester has been proposed, but the toner powder is likely to be blocked by the crystalline polyester resin, and it is difficult to maintain the storage stability. Furthermore, it becomes difficult to maintain the storage stability of the toner image after fixing.

  Good fluidity, transferability, etc., uniform charging performance, excellent anti-offset and tracking resistance, and other various toner functions are required. The surface is coated with a resin layer. A capsule toner has been proposed (see, for example, Patent Documents 5 and 6).

  The toner disclosed in Patent Document 5 suppresses volume shrinkage due to rapid cooling of a toner in which a core particle surface composed of a crystalline polyester resin having a melting point and a weight average molecular weight and a colorant is coated with an amorphous resin. While manufacturing.

  The toner disclosed in Patent Document 6 is a toner having a core-shell structure in which a shell is provided on the surface of a core particle including a crystalline polyester resin, a composite resin in which a styrene resin and a polyester resin are bonded, and colorant fine particles. The core aggregated particles are formed in the dispersion containing each fine particle, the shell resin fine particles are adhered to the surface of the core aggregated particle, and the core-shell adhered particles are combined.

  However, in the formation of the core-shell structure of these capsule toners, it is difficult to obtain a uniform core-shell junction interface. With conventional capsule toners, sufficient interface strength between the core and shell can be obtained. In addition, the fine powder generated when the shell layer is peeled off and the core layer is scraped off adheres to the carrier surface, and the charge deterioration of the developer is accelerated, and the generated fine powder easily transfers to the developing roll, photoconductor, carrier, etc. For this reason, there is a concern that the developing roll, the photoconductor and the carrier are easily contaminated, leading to deterioration of the image quality of the formed image.

Japanese Patent Publication No. 2-3172 Japanese Patent Laid-Open No. 3-100660 Japanese Patent No. 3365018 JP-A-10-307424 JP 2006-91379 A JP 2007-93809 A

An object of the present invention is to provide a toner that can stably maintain good cleaning properties for a long period of time, and that prevents toner aggregation due to the effect of the coating layer formed on the toner surface, and has excellent temporal stability, and a method for producing the same is to provide a two-component developer.

The present invention relates to a core particle obtained by pulverizing and classifying a composition containing a polyester resin as a binder resin, a colorant and other components, and a coating layer of fine resin particles formed on the surface of the core particle from it, a part of the fine resin particles forming the coating layer, a toner is a coating layer formed by at least one and fusion of the fine resin particles adjacent the core particles and coated layers, a lower Under alcohol spraying, the surface of each particle is swollen or softened and brought into contact with the surface of the core particle so that at least one of the fine resin particles is adjacent to the core particle and the coating layer. And a styrene-butyl methacrylate copolymer having a volume average particle size of 0.05 μm or more and 0.5 μm or less as fine resin particles. A toner wherein Rukoto using either Relate copolymer or methyl methacrylate.

The present invention also relates to a production method for producing the toner of the present invention, in which a core particle 100 obtained by pulverizing and classifying a composition including a polyester resin as a resin and a colorant and a colorant and other components. 1 part by weight and 30 parts by weight or less of the fine resin particles are brought into contact with each other while the surface of each particle is swollen or softened under a lower alcohol spray, so that a part of the fine resin particles are on the surface of the core particles. A toner manufacturing method for forming a coating layer formed by fusing at least one of core particles and fine resin particles adjacent in the coating layer, wherein the volume average particle size is 0.05 μm as the fine resin particles. It is characterized by using any of styrene-methyl methacrylate copolymer, styrene-butyl acrylate copolymer or methyl methacrylate having a thickness of 0.5 μm or less . A toner manufacturing method.

The present invention also includes a surface modifying apparatus comprising: a container that contains core particles and fine resin particles therein; and a spray unit that sprays lower alcohol into the container, and a stirring unit that stirs the core particles in the container. Thus, the fine resin particles are adhered to and fused to the core particles.

The present invention also includes a surface modifying apparatus comprising: a container that contains core particles and fine resin particles therein; and a spray unit that sprays lower alcohol into the container, and a stirring unit that stirs the core particles in the container. The spraying device in the container is a spraying means for spraying a mixture of fine resin particles and a lower alcohol .

  Further, the present invention is characterized in that the adhesion aid is used in a ratio of 1 part by weight or more and 99 parts by weight or less with respect to 1 part by weight of the fine resin particles.

  In the present invention, the temperature in the container is lower than the glass transition point of the binder resin contained in the core particle.

  Further, the present invention is characterized in that the adhesion aid is sprayed in a state where the core particles are suspended in the container.

Or the present invention is a two-component developer which comprises the above toner and a carrier.

According to the present invention, the coating layer containing the fine resin particles is formed on the surface of the core particles containing the binder resin and the colorant. Part of the fine resin particles is fused with at least one of the core particles and the adjacent fine resin particles to form a coating layer. Such a coating layer can prevent detachment of the coating layer from the core particles by stirring in the developing container, for example, by the fine resin particles fused to the core particles. The property of “toner”) can be prevented from changing due to long-term use. In addition, since the fine resin particles are partly fused with at least one of the core particles and the adjacent fine resin particles, and the entire fine resin particles are not in a molten state, fine particles are formed on the surface of the coating layer. A protrusion is formed. As a result, the toner is easily caught on the cleaning blade, and the cleaning property is improved. In addition, when a coating layer is formed on the entire surface of the core particle or on a large part of the core particle, the toner is prevented from agglomerating by appropriately selecting a fine resin particle material to obtain a toner having excellent temporal stability. be able to.
The core particles and the fine resin particles are brought into contact with each other in the presence of an adhesion aid that increases the adhesion between the core particles and the fine resin particles to produce a toner having the above-described effect. For example, by using an adhesion aid that increases the adhesion between the core particles and the fine resin particles by improving the wettability of the fine resin particles to the core particles, the entire surface of the core particles contains the fine resin particles. It becomes easy to form the coating layer. Such a coating layer is difficult to be detached from the core particles due to the presence of fine resin particles fused to the core particles. Accordingly, it is possible to prevent the coating layer from being detached and the properties of the toner from being changed by long-term use. Further, since the minute resin particles covering the core particles are not fused, a minute protrusion is formed on the surface of the coating layer, so that the toner is easily caught on the cleaning blade, and the toner cleaning property can be improved. it can.

  Further, the fine resin particles are fused and integrated with at least a part of the adjacent fine resin particles, so that a strong coating layer is formed and the plural fine resin particles are also fused with the core particle surface. As a result, a toner in which the core particles and the coating layer are firmly bonded can be obtained. Since the individual fine resin particles are fused with other fine resin particles at a plurality of portions, detachment of the fine resin particles from the coating layer hardly occurs. Further, since the coating layer is fused to the core particles in a very large part, the coating layer is hardly detached from the core particles.

Further, according to the present invention, since the coating layer is formed on the entire surface of the core particle, for example, exudation of a low melting point component can be suppressed and the storage stability of the toner is improved. Further, since the core particles and the coating layer are fused to each other, it is difficult to come off from the toner surface, and the stability over time is excellent.

  According to the invention, the ratio A / B between the average particle diameter A of the fine resin particles contained in the coating layer and in the fused state and the average particle diameter B of the core particles is 0.01 or more and 0.2 or less. It is. The average particle diameter A of the fine resin particles contained in the coating layer and in a fused state is the long diameter and the short diameter of the fine resin particles in a partially fused state when viewed from the surface of the coating layer. Average value. The average particle size B of the core particles is an average value of the major axis and the minor axis of the core particle when viewed from one direction. When the ratio A / B between the average particle diameter A of the fine resin particles and the average particle diameter B of the core particles is preferably 0.01 or more and 0.2 or less, the thickness of the coating layer can be optimized. In addition to preventing breakage of the coating layer due to stirring in the developing container, a coating layer containing fine resin particles can be formed over the entire surface or most of the core particles. Further, the height of the protrusion can be made suitable. As a result, toner denaturation can be prevented more stably for a longer period of time, and cleaning properties can be improved.

According to the present invention, the fine resin particles include any of styrene-methyl methacrylate copolymer, styrene-butyl acrylate copolymer, or methyl methacrylate . Such a resin is preferable because it has many advantages such as light weight, high strength, high transparency, and low cost.

  According to the invention, the core particle includes at least a binder resin containing a crystalline polyester resin and an amorphous polyester resin, a colorant, and a release agent. With this configuration, even if the number of low-softening components in the toner is increased, exposure of the low-softening components to the toner surface can be suppressed, and the surface hardness is increased and storage stability is maintained without impairing fixing properties. , Mechanical strength can be improved.

According to the present invention, the core particles and the fine resin particles having a volume average particle diameter of 0.05 μm or more and less than 1 μm are brought into contact with each other while the core particle surface and the fine resin particle surface are swollen or softened under the spray of the lower alcohol. Thus, a toner having the above effect is manufactured. For example, by using a lower alcohol that increases the adhesion between the core particles and the fine resin particles by improving the wettability of the fine resin particles with respect to the core particles, the entire surface of the core particles is coated with the fine resin particles over the entire surface. It becomes easy to form a layer. Such a coating layer is difficult to be detached from the core particles due to the presence of fine resin particles fused to the core particles. Accordingly, it is possible to prevent the coating layer from being detached and the properties of the toner from being changed by long-term use. Moreover, since the volume average particle diameter of the fine resin particles before fusion is 0.05 μm or more and 1.0 μm or less, the protrusion formed by fusing the fine resin particles with the core particles or adjacent fine resin particles The average particle diameter A can be made suitable, and the cleaning property can be further improved.

According to the present invention, by there use a low-grade alcohol, it is possible to enhance the wettability to the core particles of the fine resin particles, to form a coating layer containing fine resin particles on the surface all the surface of the core particles It becomes even easier. Also, the drying time for removing the lower alcohol can be further shortened.

  According to the invention, the fine resin particles are used in a ratio of 1 part by weight to 30 parts by weight with respect to 100 parts by weight of the core particles. When the fine resin particles are used at such a ratio, the fine resin particles can be attached to the entire surface of the core particles, and a coating layer can be formed on the entire surface of the core particles. This can more reliably prevent the toner from aggregating due to the low melting point component contained in the core particles.

Further, according to the present invention, a container containing the core particles and the fine resin particles therein, and a lower alcohol (hereinafter, sometimes referred to as an adhesion aid as a term meaning the lower alcohol in the present invention) are sprayed inside the container. The fine resin particles are adhered and fused to the core particles by a surface modification device that includes a spraying means and a stirring means for stirring the core particles in the container. By such a method, it is possible to adhere the fine resin particles to the core particles using an adhesion aid. When such a surface modification device is used, it is easy to set the use ratio of the core particles and the fine resin particles, and the thickness of the coating layer can be made suitable.

  In addition, according to the present invention, the container includes the container for storing the core particles therein, and the spraying means for spraying the mixture of the fine resin particles and the adhesion aid inside the container, and the stirring for stirring the core particles in the container. The fine resin particles are adhered and fused to the core particles by a surface modification device provided with means. Also by such a method, the fine resin particles can be attached to the core particles using the adhesion assistant, and it is easy to fuse a uniform amount of the fine resin particles to the core particles.

  According to the invention, the adhesion aid is used in a proportion of 1 part by weight or more and 99 parts by weight or less with respect to 1 part by weight of the fine resin particles. When the mixture of the fine resin particles and the adhesion aid is sprayed from the same spraying means, a mixture in which the fine resin particles and the adhesion aid are mixed at the above ratio is used, whereby the fine resin particles with respect to the core particles are used. The wettability can be sufficiently increased, and the time for removing the adhesion aid can be shortened. Further, the viscosity of the mixture is suitable, and the spraying of the mixture by the spraying means is easy.

  Further, according to the present invention, since the temperature in the container is lower than the glass transition point of the binder resin contained in the core particles, the aggregation of the core particles generated when the core particles are excessively melted in the container at the time of toner production. Can be prevented.

  According to the present invention, the mixture of the fine resin particles and the adhesion aid is sprayed in a state where the core particles float in the container. As a result, the time required for the core particles sprayed with the adhesion aid to contact each other can be shortened, and toner aggregation is prevented at the time of toner production, so that the generation of coarse particles is prevented and the particle size is adjusted. Toner can be obtained.

  Further, according to the present invention, by using the toner of the present invention, a stable charging characteristic can be maintained in a two-component developer used by mixing with a carrier.

  Further, according to the present invention, a toner image can be stably formed on the photosensitive member by using a developing device that performs development using the developer of the present invention.

  Further, according to the present invention, a stable image with good reproducibility can be formed by using an image forming apparatus that forms an image using the developing device of the present invention.

The toner of the present invention comprises a core particle obtained by pulverizing and classifying a composition containing a polyester resin as a binder resin , a colorant and other components, and fine resin particles formed on the surface of the core particle. A toner comprising a coating layer, wherein a part of the fine resin particles forming the coating layer is fused with at least one of the core particles and the adjacent fine resin particles in the coating layer; The ratio A / B between the average particle diameter A of the fine resin particles contained in the coating layer and in the fused state and the average particle diameter B of the core particles is 0.01 or more and 0.2 or less. The particles are either styrene-methyl methacrylate copolymer, styrene-butyl acrylate copolymer or methyl methacrylate .

  Since the toner of the present invention has fine resin particles fused to the core particles, the coating layer can be prevented from being detached from the core particles by stirring in the developing container, for example. This prevents changes in the properties of the toner due to long-term use. In addition, since the fine resin particles are partly fused with at least one of the core particles and the adjacent fine resin particles, and the entire fine resin particles are not in a molten state, fine particles are formed on the surface of the coating layer. A protrusion is formed. As a result, the toner is easily caught on the cleaning blade, and the cleaning property is improved. Further, when the coating layer is formed on the entire surface of the core particles, the toner can be prevented from agglomeration and a toner having excellent stability over time can be obtained by appropriately selecting a fine resin particle material.

In the toner of the present invention, the ratio A / B between the average particle diameter A of the fine resin particles contained in the coating layer and in the fused state and the average particle diameter B of the core particles is 0.01 or more and 0.2 or less. there is an average particle diameter a of the fine resin particles in the fused state is included in the coating layer, and the major axis when the part is viewed fine resin particles in the state of being fused from the coated layer surface short The average value with the diameter. The average particle size B of the core particles is an average value of the major axis and the minor axis of the core particle when viewed from one direction.

  The average particle diameter A of the fine resin particles in the fused state depends on the volume average particle diameter of the fine resin particles before fusion. However, depending on the fusion state of the fine resin particles, the volume average particle size of the fine resin particles before fusion may be greatly different from the average particle size A of the fine resin particles in the fusion state. Therefore, in the present invention, the average particle diameter of the fine resin particles after the formation of the coating layer, that is, the fine resin particles partly in a fused state is defined as the average particle diameter A. Hereinafter, the “average particle diameter A of fine resin particles in a fused state” may be referred to as “average particle diameter A of protrusions”.

  The average particle diameter A of the protrusions is calculated as follows. For example, the toner on which the coating layer is formed is photographed at a magnification of 10,000 times with an electron microscope (trade name: VE-9800, manufactured by Keyence Corporation). Next, in the photographed image of the toner, a plurality of, for example, five circles having a radius of 1.5 μm (1.5 cm on the photograph) are set in the photographed image of the toner. The average particle diameter A is measured for the fused fine resin particles present in the set circle. The plurality of fine resin particles, some of which are in a fused state, have a plurality of protrusions formed on the surface of the coating layer. Of the plurality of protrusions in the set circle, the length of a straight line connecting the recesses forming the one protrusion and the center of the fine resin particles is measured. The length of this straight line is hereinafter referred to as “distance between the recesses”. The center of the fine resin particles is the most convex portion of the protrusion, and is determined by visual observation, for example. Of the distances between the recesses forming the projections, the minimum distance is defined as the minor axis A1 of the projections. The maximum distance is the major axis A2 of the protrusion. The average value of the short axis average value A1 and the long axis A2, that is, the average diameter {(A1 + A2) / 2} is obtained, and the average diameter is calculated for a plurality of protrusions present in a plurality of circles. Get the average value. The value calculated in this way is the average particle diameter A of the protrusions, that is, the average particle diameter A of the fine resin particles contained in the coating layer and in a fused state.

  The average particle size B of the core particles is calculated as follows. For example, the core particle is photographed at a magnification of 5000 times with the electron microscope. From this photograph, the minor axis B1 and the major axis B2 of the core particle are measured, and the average value of the minor axis B1 and the major axis B2, that is, {(B1 + B2) / 2} is defined as the average particle diameter B of the core particle.

When the ratio A / B between the average particle diameter A of the fine resin particles calculated by the above method and the average particle diameter B of the core particles is 0.01 or more and 0.2 or less, the thickness of the coating layer is reduced. Can be preferred. The thickness of the coating layer can be determined from the difference between the particle size of the toner after coating the coating layer and the particle size of the core particles. When the thickness of the coating layer is suitable, breakage of the coating layer due to stirring in the developing container can be prevented, and a coating layer containing fine resin particles can be formed over the entire surface of the core particles. Further, when the ratio A / B is 0.01 or more and 0.2 or less, the size of the minute protrusions formed by the minute resin particles can be made suitable. As a result, the toner can be prevented from being denatured for a longer period of time, and the cleaning property can be maintained.

  When the ratio A / B is less than 0.01, the thickness of the coating layer is smaller than the average particle size B of the core particles, and the coating layer may be broken by stirring in the developing container. There is a possibility that stability cannot be obtained. When the ratio A / B exceeds 0.2, the particle diameter of the fine resin particles before forming the coating layer is larger than the average particle diameter B of the core particles, and the fusion between the fine resin particles and the core particles; It is difficult to fuse fine resin particles. If fusion between the fine resin particles and the core particles and fusion between the fine resin particles are difficult, a coating layer containing the fine resin particles may not be formed over the entire surface of the core particles.

  The toner of the present invention contains a binder resin, a colorant, and other toner additive components. Examples of other toner additive components include a release agent and a charge control agent. The method for producing the toner of the present invention will be described below. The toner of the present invention is produced, for example, by attaching and fusing the fine resin particles to the core particles using an adhesion assistant that increases the adhesion between the core particles and the fine resin particles.

  FIG. 1 is a process diagram showing a procedure of a toner manufacturing method according to an embodiment of the present invention. The toner manufacturing method in the present embodiment includes a core particle preparation step in step s1, a fine resin particle and adhesion aid preparation step in step s2, and a coating step in step s3. The temporal order of the core particle preparation process of step s1 and the fine resin particles and the adhesion aid preparation process of step s2 may be reversed.

<Core particle production process>
In the core particle preparation step of step s1, core particles containing a binder resin and a colorant are prepared. The core particles used in the toner of the present invention contain a binder resin and a colorant, and may further contain a release agent, a charge control agent and the like.

As the polyester resin which is a binder resin, known resins can be preferably used.

In the present invention, the derivative thereof lay also acrylic acid, in addition to acrylic acid, methyl acrylate, ethyl acrylate, isopropyl acrylate, n- butyl acrylate, isobutyl acrylate, n- amyl acrylate, isoamyl acrylate, Esters of acrylic acid and aliphatic lower alcohols such as n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, decyl acrylate, dodecyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, etc. Examples include esters of acrylic acid and hydroxylalkyl groups.
As methacrylic acid or derivatives thereof, in addition to methacrylic acid, methyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-methacrylic acid 2- Esters of acrylic acid and aliphatic lower alcohols such as ethylhexyl, n-octyl methacrylate, decyl methacrylate, dodecyl methacrylate, etc., methacrylic acid such as hydroxyethyl methacrylate, hydroxypropyl methacrylate, and hydroxylalkyl groups Ester etc. are mentioned.
The binder resin of the present invention is a resin obtained by polymerizing acrylic acid, methacrylic acid or a derivative thereof and styrene alone, or two or more kinds of polymers selected from acrylic acid, methacrylic acid or a derivative thereof and styrene. And a copolymer produced.

The fine resin particles constituting the coating layer may be any one of styrene-methyl methacrylate copolymer, styrene-butyl acrylate copolymer, or methyl methacrylate, and these resins use a general radical initiator. Those obtained by solution polymerization, suspension polymerization, emulsion polymerization and the like can be preferably used.

  The binder resin preferably has a glass transition point of 30 ° C. or higher and 80 ° C. or lower. If the glass transition point of the binder resin is less than 30 ° C., blocking in which the toner thermally aggregates easily occurs in the image forming apparatus, and storage stability may be lowered. When the glass transition point of the binder resin exceeds 80 ° C., the fixability of the toner to the recording medium is lowered, and there is a possibility that fixing failure occurs.

  As the colorant, organic dyes, organic pigments, inorganic dyes, inorganic pigments and the like commonly used in the electrophotographic field can be used.

  Examples of the black colorant include carbon black, copper oxide, manganese dioxide, aniline black, activated carbon, nonmagnetic ferrite, magnetic ferrite, and magnetite.

  Examples of yellow colorants include chrome lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S, Hansa yellow G, Hansa yellow 10G, benzidine yellow G, and benzidine. Yellow GR, Quinoline Yellow Lake, Permanent Yellow NCG, Tartrazine Lake, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 138, and the like.

  Examples of the orange colorant include red chrome yellow, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, indanthrene brilliant orange RK, benzidine orange G, indanthrene brilliant orange GK, C.I. I. Pigment orange 31, C.I. I. And CI Pigment Orange 43.

  Examples of red colorants include bengara, cadmium red, red lead, mercury sulfide, cadmium, permanent red 4R, risol red, pyrazolone red, watching red, calcium salt, lake red C, lake red D, and brilliant carmine 6B. Eosin Lake, Rhodamine Lake B, Alizarin Lake, Brilliant Carmine 3B, C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.

  Examples of purple colorants include manganese purple, fast violet B, and methyl violet lake.

  Examples of blue colorants include bitumen, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated products, first sky blue, induslen blue BC, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 16, C.I. I. And CI Pigment Blue 60.

  Examples of the green colorant include chrome green, chromium oxide, pigment green B, micalite green lake, final yellow green G, C.I. I. And CI Pigment Green 7.

  Examples of the white colorant include compounds such as zinc white, titanium oxide, antimony white, and zinc sulfide.

  One colorant can be used alone, or two or more different colorants can be used in combination. Moreover, even if it is the same color, 2 or more types can be used together. The amount of the colorant to be used is not particularly limited, but is preferably 0.1 to 20 parts by weight, more preferably 0.2 to 10 parts by weight with respect to 100 parts by weight of the binder resin.

  As the release agent, those commonly used in this field can be used, for example, petroleum wax such as paraffin wax and derivatives thereof, microcrystalline wax and derivatives thereof, Fischer-Tropsch wax and derivatives thereof, polyolefin wax (polyethylene wax, polypropylene Wax etc.) and derivatives thereof, low molecular weight polypropylin wax and derivatives thereof, hydrocarbon polymer waxes such as polyolefin polymer wax (low molecular weight polyethylene wax etc.) and derivatives thereof, carnauba wax and derivatives thereof, rice wax and derivatives thereof , Candelilla wax and its derivatives, plant wax such as wood wax, animal wax such as beeswax and whale wax, fatty acid amide, phenol fatty acid ester, etc. Oil-based synthetic waxes, long-chain carboxylic acids and their derivatives, long-chain alcohols and derivatives thereof, silicone polymers, such as higher fatty acids. Derivatives include oxides, block copolymers of vinyl monomers and waxes, graft modified products of vinyl monomers and waxes, and the like. The amount of the wax used is not particularly limited and can be appropriately selected from a wide range, but is preferably 0.2 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, particularly preferably 100 parts by weight of the binder resin. 1.0 to 8.0 parts by weight.

  As the charge control agent, those for positive charge control and negative charge control commonly used in this field 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. Derivatives, guanidine salts, amidine salts and the like can be mentioned. As charge control agents for controlling negative charges, oil-soluble dyes such as oil black and spiron black, metal-containing azo compounds, azo complex dyes, metal salts of naphthenic acid, salicylic acid and its derivatives, metal complexes and metal salts (metal is Chromium, zinc, zirconium, etc.), fatty acid soaps, long-chain alkyl carboxylates, resin acid soaps, and the like. The charge control agent can be used alone or in combination of two or more as required. The amount of the charge control agent used is not particularly limited and can be appropriately selected from a wide range. The charge control agent may be contained in the core particles, or may be used by being mixed in a coating layer made of fine resin particles in the coating step described later. When the charge control agent is contained in the core particles, the charge control agent is preferably 0.5 to 3 parts by weight with respect to 100 parts by weight of the binder resin.

  The core particles can be manufactured according to a general toner manufacturing method. As a general toner production method, for example, a dry method such as a pulverization method, a suspension polymerization method, an emulsion aggregation method, a dispersion polymerization method, a dissolution suspension method, and a wet emulsion method such as a melt emulsification method are used. A method for producing core particles by the pulverization method will be described below.

  In the pulverization method, a toner composition containing a binder resin, a colorant, and other toner additive components is dry-mixed with a mixer and then melt-kneaded with a kneader. The kneaded material obtained by melt kneading is cooled and solidified, and the solidified material is pulverized by a pulverizer. Thereafter, particle size adjustment such as classification is performed as necessary to obtain core particles.

  Known mixers can be used, such as Henschel mixer (trade name, 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.), etc. Henschel type mixing device, Ong mill (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.), and the like.

  A well-known thing can be used also as a kneading machine, for example, common kneading machines, such as a twin-screw extruder, a 3 roll, a laboratory blast mill, can be used. More specifically, for example, TEM-100B (trade name, manufactured by Toshiba Machine Co., Ltd.), PCM-65 / 87, PCM-30 (all of which are trade names, manufactured by Ikegai Co., Ltd.), etc. Extruder, Needex (trade name, manufactured by Mitsui Mining Co., Ltd.) and other open roll type kneaders.

  Synthetic resin additives such as colorants may be used as a master batch in order to uniformly disperse the synthetic resin additive in the kneaded product. Two or more additives for synthetic resin may be used as composite particles. The composite particles can be produced, for example, by adding an appropriate amount of water, lower alcohol or the like to two or more additives for synthetic resin, granulating with a general granulator such as a high speed mill, and drying. Masterbatches and composite particles are mixed into the powder mixture during dry mixing.

  The obtained core particles preferably have an average particle size B of 3 μm or more and 10 μm or less, and more preferably 5 μm or more and 8 μm or less. When the average particle diameter B of the core particles is 3 μm or more and 10 μm or less, a high-definition image can be stably formed over a long period of time. When the average particle size B of the core particles is less than 3 μm, the particle size of the core particles becomes too small, and there is a possibility that high charging and low fluidization may occur. When this high charging and low fluidization occur, it becomes impossible to stably supply the toner to the photoreceptor, and there is a possibility that background fogging and a decrease in image density may occur. When the average particle diameter B of the core particles exceeds 10 μm, the particle diameter of the core particles is large, so that a high-definition image cannot be obtained. Further, as the particle diameter of the core particle increases, the specific surface area decreases, and the charge amount of the toner decreases. When the charge amount of the toner is small, the toner is not stably supplied to the photoconductor, and there is a possibility that in-machine contamination due to toner scattering occurs.

<Micro resin particle and lower alcohol preparation process>
The fine resin particles of steps s2 and a lower alcohol preparation process, prepare a fine resin particles containing at least a resin.

  The resin contained in the fine resin particles may be the same type as the binder resin of the core particles, or a different type of resin, but a different type of resin in terms of surface modification of the toner. Is preferably used. When a different kind of resin is used as the resin contained in the fine resin particles, it is preferable to use a resin whose softening point of the resin contained in the fine resin particles is higher than the softening point of the binder resin of the core particles. As a result, the toner is prevented from fusing with each other during storage, and storage stability can be improved. The softening point of the resin contained in the fine resin particles is preferably 80 ° C. or higher and 140 ° C. or lower, although it depends on the image forming apparatus in which the toner is used. By using a resin having such a temperature range, a toner having both storage stability and fixing ability can be obtained.

Such fine resin particles can be obtained, for example, by polymerization of monomers.
It can also be obtained by emulsifying and dispersing fine resin particle raw materials with a homogenizer or the like. It can also be obtained by monomer polymerization.

  The volume average particle size of the fine resin particles before fusing needs to be sufficiently smaller than the average particle size B of the core particles. Furthermore, the volume average particle diameter of the fine resin particles before fusion is preferably 0.05 μm or more and less than 1 μm. The volume average particle size of the fine resin particles before fusion is more preferably 0.05 μm or more and 0.5 μm or less. When the volume average particle size of the fine resin particles before fusion is 0.05 μm or more and 0.5 μm or less, a protrusion having a suitable size is formed on the surface of the coating layer. As a result, the toner is easily caught on the cleaning blade during cleaning, and the cleaning performance is improved. In addition, even if the amount of low-softening components in the toner is increased, exposure of the low-softening components to the toner surface can be suppressed, and the surface hardness is increased without impairing the fixability, thereby improving storage stability and mechanical strength. be able to.

  If the volume average particle size of the fine resin particles before fusing is less than 0.05 μm, the height of the formed protrusions becomes small, and the cleaning property may be deteriorated. In addition, the size of the particles becomes too small, and the handleability of the fine resin particles decreases. In addition, when the fine resin particle dispersion containing the fine resin particles and the adhesion assistant is sprayed from the same spray nozzle in the coating process described later, the dispersibility of the fine resin particles in the fine resin particle dispersion may be reduced. is there.

  When the volume average particle size of the fine resin particles before fusing is 1 μm or more, the height of the formed protrusions is increased, thereby increasing the ratio of the coating layer in the toner. In addition, it becomes difficult to uniformly fuse the toner surface. When the ratio of the coating layer in the toner increases, although depending on the material for forming the coating layer, the influence of the coating layer at the time of image formation becomes too large and a desired image may not be formed.

In the fine resin particle and adhesion aid preparation step in step s2, lower alcohol that increases the adhesion between the core particles and the fine resin particles is used. Lower alcohol Ru can improve wettability to the core particles of the fine resin particles. The lower alcohol is preferably one that does not dissolve the core particles. The lower alcohol is preferred because it is easy emits steam after coating the fine resin particles.

Examples of the lower alcohol include methanol, ethanol, propanol and the like. Such lower alcohols may be used alone or in admixture of two or more, and may be used as a mixture with water as long as it can contribute to adhesion of the core particles and the fine resin particles.

<Coating process>
In the coating process of step s3, the fine resin particles are adhered and fused to the core particles using an adhesion assistant . As a result, the core particles are coated with the fine resin particles to form a coating layer.

  The coating process is performed using, for example, a surface modifying apparatus. The surface modification device is a device that includes a container that accommodates core particles and fine resin particles therein, and a spraying means that sprays an adhesion aid inside the container. Further, in the present embodiment, the surface modification apparatus includes a stirring unit that stirs the core particles in the container.

  A closed container can be used as a container for containing the core particles and the fine resin particles. The spraying means is a core for storing an adhesion aid storage part for storing an adhesion aid, a carrier gas storage part for storing a carrier gas, an adhesion assistant and a carrier gas, and a resulting mixture contained in a container. A liquid spraying unit that sprays toward the particles and sprays droplets of the deposition aid onto the core particles. Compressed air or the like can be used as the carrier gas. Commercially available products can be used as the liquid spray unit. For example, a two-fluid nozzle (trade name: HM-6 type, a sticking auxiliary agent is passed through a tube pump (trade name: MP-1000A, manufactured by Tokyo Rika Kikai Co., Ltd.) A product connected so as to be quantitatively fed to Fuso Seiki Co., Ltd. can be used. As the stirring means, a stirring rotor or the like capable of imparting mechanical and thermal energy mainly composed of impact force to the core particles is used.

  Commercially available products can be used as the container equipped with the stirring means. For example, Henschel mixer (trade name, manufactured by Mitsui Mining Co., Ltd.), super mixer (trade name, manufactured by Kawata Co., Ltd.), Mechano Mill (trade name, Okada Seiko) Henschel type mixing equipment such as Co., Ltd., 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. By installing the liquid spray unit in the container of such a mixer, this mixer can be used as the surface modification device of the present embodiment.

  The coating of the fine resin particles on the core particles is performed as follows. First, core particles and fine resin particles are put into a container, and an adhesion assistant is sprayed inside the container in a state where the core particles and the fine resin particles are stirred by the stirring means. The surface of the core particles and the fine resin particles is swelled and softened by spraying the adhesion aid and applying thermal energy by stirring. A mechanical impact force is applied to this by a stirring means, and the fine resin particles adhere to the surface of the core particles, and a part of the fine resin particles are fused with at least one of the core particles and the adjacent fine resin particles. To wear. As a result, the fine resin particles can be adhered to the entire surface of the core particles, and the fine resin particles can be fused to the entire surface of the core particles.

  It is preferable that the temperature in the container of the surface modification device is lower than the glass transition point of the binder resin contained in the core particles. If the temperature in the container is equal to or higher than the glass transition point of the binder resin contained in the core particles, the core particles may be excessively melted in the container at the time of toner production, and the core particles may be aggregated. Therefore, in order to prevent agglomeration of the core particles, it is preferable that the inside of the surface modification device is cooled as necessary.

  Further, the adhesion aid is preferably sprayed in a state where the core particles float in the container. When the mixture of the fine resin particles and the adhesion aid is sprayed in a state where the core particles are suspended in the container, the time for the core particles sprayed with the adhesion aid to be brought into contact with each other can be shortened. As a result, toner aggregation during toner production can be prevented and generation of coarse particles can be prevented, so that a toner having a uniform particle diameter can be obtained. The state in which the core particles float in the container can be realized, for example, by stirring with stirring means, supplying air, or the like.

  Although the usage rate of the fine resin particles is not particularly limited, it is necessary to be a usage rate that can cover the entire surface of the core particles. The fine resin particles are preferably used at a usage rate of 1 to 30 parts by weight with respect to 100 parts by weight of the core particles. If the fine resin particles are less than 1 part by weight, the entire surface of the core particles may not be covered with the coating layer. If the fine resin particles exceed 30 parts by weight, the thickness of the coating layer becomes too large, and depending on the constituent material of the fine resin particles, the fixability of the toner may be lowered.

  The amount of the adhesion aid is not particularly limited, but it is preferably an amount that wets the entire surface of the core particles. The amount of adhesion aid used is determined by the amount of core particles used. Moreover, the amount of the adhesion assistant can be adjusted by the spraying time by the spraying means, the number of spraying, and the like. Therefore, the spraying amount per unit time by the spraying means is set according to the average particle diameter of the core particles, the use ratio of the core particles and the fine resin particles, the material of the core particles and the material of the fine resin particles, etc. When most of the fine resin particles adhere to the core particles, the spraying of the adhesion aid by the spraying means may be terminated.

  The coating of the fine resin particles on the core particles is performed by a surface modification device including a container that accommodates the core particles inside, and a spraying means that sprays a mixture of the fine resin particles and the adhesion auxiliary agent inside the container. Also good. As such a surface modification device, the same device as that described above can be used except that the mixture of the adhesion assistant and the fine resin particles is stored in the adhesion assistant reservoir.

  The coating of the fine resin particles onto the core particles by such a surface modification apparatus is performed as follows. First, core particles are put into a container, and a mixture of an adhesion assistant and fine resin particles is sprayed inside the container in a state where the core particles are stirred by a stirring means. The surface of the core particle is swollen and softened by spraying the adhesion aid and applying thermal energy by stirring. The fine resin particles are mixed together with the adhesion aid, and after sprayed inside the container, they are agitated and applied with thermal energy, and the surface thereof is swollen and softened like the core particles. A mechanical impact force is applied to this by a stirring means, and the fine resin particles adhere to the surface of the core particles, and a part of the fine resin particles are fused with at least one of the core particles and the adjacent fine resin particles. To wear. As a result, the fine resin particles can be adhered to the entire surface of the core particles, and the fine resin particles can be fused to the entire surface of the core particles.

  When spraying a mixture of an adhesion aid and fine resin particles, the adhesion aid is preferably used in a proportion of 1 part by weight or more and 99 parts by weight or less with respect to 1 part by weight of the fine resin particles. The coating liquid, which is a mixture of the adhesion aid and the fine resin particles, is prepared in the fine resin particle and adhesion aid preparation step in step s2. When the mixture of the fine resin particles and the adhesion aid is sprayed from the same spraying means, a mixture in which the fine resin particles and the adhesion aid are mixed at the above ratio is used, whereby the fine resin particles with respect to the core particles are used. The wettability can be sufficiently increased, and the time for removing the adhesion aid can be shortened. Further, the viscosity of the mixture is suitable, and the spraying of the mixture by the spraying means is easy. If the adhesion aid is less than 1 part by weight, the viscosity of the mixture becomes too high and the nozzle holes of the spray unit may be clogged. If the adhesion aid exceeds 99 parts by weight, the content of the adhesion aid will be too high, and the time for removing the adhesion aid will be too long.

  The amount of the mixture of the fine resin particles and the adhesion aid is not particularly limited, but it is necessary to include an amount of fine resin particles that can cover the entire surface of the core particles. The preferred amount of the fine resin particles that can cover the entire surface of the core particles is 1 to 30 parts by weight with respect to 100 parts by weight of the core particles as described above. It is determined according to the content of the fine resin particles in the mixture.

  When the coating of the fine resin particles on the entire surface of the core particles is completed, the adhesion aid is removed. The removal of the adhesion aid is performed by vaporizing the adhesion aid with a dryer, for example. For removal of the adhesion aid, for example, a commonly used dryer such as a hot air receiving dryer, a conductive heat transfer dryer, or a freeze dryer is used.

  As described above, a part of the fine resin particles contained in the coating layer is fused with at least one of the core particles and the adjacent fine resin particles, and is formed on the entire surface of the core particles. The toner of the present invention including the coating layer is obtained. In such a toner, the adhesion between the coating layer and the core particle is strengthened by the fine resin particles fused to the core particle, and therefore, for example, the coating layer is detached from the core particle by stirring in the developing container. It is possible to prevent the toner properties from changing due to long-term use. In addition, since only a part of the fine resin particles are fused, a fine protrusion is formed on the surface of the coating layer by the non-fused part of the fine resin particles covering the core particles. As a result, the toner is easily caught on the cleaning blade, and the cleaning property is improved. Further, the surface area of the toner is increased due to the formation of the protrusions, and a better triboelectric chargeability can be obtained as compared with the toner in which the coating layer is not formed on the core particles. Thereby, transferability and developability are improved, and a high-quality image can be formed.

  An external additive may be added to the toner of the present invention. Known external additives can be used, and examples thereof include silica and titanium oxide. These are preferably surface-treated with a silicone resin, a silane coupling agent or the like. The amount of the external additive used is preferably 1 to 10 parts by weight with respect to 100 parts by weight of the toner.

  The toner of the present invention can be used as a one-component developer or a two-component developer. When used as a one-component developer, the toner is used only without using a carrier. When used as a one-component developer, a blade and a fur brush are used, and the toner is conveyed by frictional charging with a developing sleeve to adhere the toner onto the sleeve, thereby forming an image. When used as a two-component developer, the toner of the present invention is used with a carrier. As the carrier, a known carrier can be used. For example, a resin-coated carrier or a resin in which iron or copper, zinc, nickel, cobalt, manganese, chromium or the like alone or a composite ferrite and carrier core particles are coated with a coating material. And a resin-dispersed carrier in which magnetic particles are dispersed. Known coating materials can be used, such as polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin, metal compound of ditertiary butylsalicylic acid, styrene resin, acrylic resin , Polyamide, polyvinyl butyral, nigrosine, amino acrylate resin, basic dye, basic dye lake, silica fine powder, alumina fine powder, and the like. 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 resin, a fluorine resin, a phenol resin, etc. are mentioned. Either of them is preferably selected according to the toner component, and one kind can be used alone or two or more kinds can be used in combination.

The shape of the carrier is preferably a spherical shape or a flat shape. The particle size of the carrier is not particularly limited, but is preferably 10 to 100 μm, more preferably 20 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, when a bias voltage is applied to the developing sleeve, charges are injected into the carrier, and carrier particles easily adhere to the photoreceptor. Further, breakdown of the bias voltage is likely to occur.

  The magnetization strength (maximum magnetization) of the carrier is preferably 10 to 60 emu / g, more preferably 15 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, the rising of the carrier becomes too high, so that it is difficult to maintain the non-contact state with the image carrier in the non-contact development. 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, if the resin-coated carrier (density 5 to 8 g / cm ² ) is taken as an example, the development is performed. The toner may be used so that the toner is contained in 2 to 30% by weight, preferably 2 to 20% by weight of the total amount of the developer. In the two-component developer, the coverage of the carrier with toner is preferably 40 to 80%.

FIG. 2 is a cross-sectional view schematically showing the configuration of the image forming apparatus 1 using the developer 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 or monochrome image on a recording medium in accordance with transmitted image information. That is, 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, information A print mode is selected by a control unit (not shown) in response to reception of a print job from an external device using a recording storage medium or a memory device. The image forming apparatus 1 includes a toner image forming unit 2, a 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. Here, each member provided by four according to each color is distinguished by attaching an alphabet representing each color to the end of the reference symbol, and when referring collectively, 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 unit 14, and a cleaning unit 15. The charging unit 12, the developing unit 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 unit 14 and the cleaning unit 15 in the vertical direction.

  The photosensitive drum 11 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 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 a conductive film, conductive particles and / 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. 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, to prevent deterioration of the chargeability of the photosensitive layer during repeated use. Alternatively, an advantage of improving the charging characteristics of the photosensitive layer in a low humidity environment can be obtained. Further, a laminated photoreceptor having a three-layer structure having a high durability and having a photoreceptor surface protective layer as the uppermost layer may be used.

  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, for example, perylene pigments such as perylene imide and perylene acid anhydride, polycyclic quinone pigments such as quinacridone and anthraquinone, metal and metal-free phthalocyanines, and halogenated compounds. 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 a fluorene ring and / or a fluorenone ring, bisazo pigments composed of aromatic amines, trisazo pigments, etc. have high charge generation ability and high sensitivity. Suitable for obtaining a photosensitive layer. 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 to 500 parts by weight, more preferably 10 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 film thickness of the charge generation layer thus obtained is not particularly limited, but is preferably 0.05 to 5 μm, more preferably 0.1 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 derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensation product and derivatives thereof, 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-benzothiazoline -Donating substances such as azine compounds, fluorenone derivatives, dibenzothiophene derivatives, indenothiophene derivatives, phenanthrenequinone derivatives, indenopyridine derivatives, thioxanthone derivatives, benzo [c] cinnoline derivatives, phenazine oxide derivatives, tetracyano Examples include electron-accepting substances such as ethylene, 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 material. 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 film thickness of the charge generation layer thus obtained is not particularly limited, but is preferably 10 to 50 μm, more preferably 15 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 formed by forming the organic photosensitive layer using the charge generation material and the charge transport material as described above is used. 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 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. .

  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 unit 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 b, c, m, and y 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.

Figure 3 is a cross-sectional view schematically showing a configuration of a current image unit 14 using the developer of the present invention. The developing unit 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 the toner may be directly supplied from each color toner cartridge.

  The cleaning unit 15 removes the toner remaining on the surface of the photosensitive drum 11 after transferring the toner image to the recording medium, 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 1 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. Surface degradation is likely to proceed due to the chemical action of ozone generated by the discharge. 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 means 14 to form a toner image, and 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 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, an intermediate transfer roller 28 (b, c, m, y), and a transfer belt cleaning unit. 29 and the 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 is driven to rotate in the direction of an arrow B. 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 photoconductor drum 11 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. Since the toner adhering to the intermediate transfer belt 25 due to contact with the photosensitive drum 11 causes the back surface of the recording medium to be contaminated, the transfer belt cleaning unit 29 removes and collects the toner on the surface of the intermediate transfer belt 25. 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 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 rotates the intermediate transfer belt 25 in the arrow B direction. It is conveyed to a transfer nip portion by driving, 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 fixing condition control means described later. The control of the heating temperature by the fixing condition control means will be described in detail 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. 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 drive of the pressure roller 32. 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 onto which the toner image is transferred by the transfer unit 3 is sandwiched between the fixing roller 31 and the pressure roller 32, and the toner image is recorded under heating when passing through the fixing nip portion. By being pressed against the 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, a transport roller 37, 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 part of the image forming apparatus 1 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 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 37 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 1 by manual operation, and the recording medium taken from the manual paper feed tray 39 passes through the paper conveyance path S2 by the conveyance roller 37. Then, 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, a discharge roller 40, and a discharge tray 41. The conveyance roller 37 is provided downstream 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 1. The discharge tray 41 stores a recording medium on which an image is fixed.

  The image forming apparatus 1 includes a control unit (not shown). For example, the control unit is provided in an upper part of the internal space of the image forming apparatus 1 and includes a storage unit, a calculation unit, and a control unit. The storage unit of the control unit includes various setting values via an operation panel (not shown) arranged on the upper surface of the image forming apparatus 1, detection results from sensors (not shown) arranged at various locations inside the image forming apparatus 1, external devices, and the like. The image information from is input. 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 capable of forming or obtaining image information and electrically connected to the image forming apparatus 1 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 apparatus, portable terminal apparatus, 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 toner of the present invention, by forming an image using a two-component developer and the developing device 14, the image forming apparatus 1, it is possible to form a good quality image fixability over a long period.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. In the following, “parts” and “%” mean “parts by weight” and “% by weight” unless otherwise specified. The average particle diameter A of the protrusions, the average particle diameter B of the core particles, the coefficient of variation (CV value), and the volume average particle diameter of the fine resin particles before fusion in the examples and comparative examples were measured as follows. did. Further, the glass transition point (Tg) and softening point (Tm) of the binder resin used in Examples and Comparative Examples, and the melting point of the release agent were measured as follows.

[Measurement of average particle diameter A of protrusions]
The toner on which the coating layer was formed was photographed at a magnification of 10,000 times with an electron microscope (trade name: VE-9800, manufactured by Keyence Corporation). In the photograph taken of the toner, the minor axis A1 of the protrusion included in a circle having a radius of 1.5 μm (1.5 cm on the photograph) centered on the central portion of the toner and present in the portion included in the toner The major axis A2 was measured. The average value of the minor axis A1 and the major axis A2, that is, {(A1 + A2) / 2} was defined as the average particle diameter A of the protrusions.

[Measurement and coefficient of variation (CV value) of average particle diameter B of core particles]
The core particles were photographed at a magnification of 5000 times with the electron microscope, and the short diameter B1 and the long diameter B2 of the core particles were measured from the photograph. The average value of the minor axis B1 and the major axis B2, that is, {(B1 + B2) / 2} was defined as the average particle diameter B of the core particles. Moreover, it computed from the following formula based on the measured average particle diameter B of the core particle and its standard deviation.
Coefficient of variation = standard deviation / average particle size B of core particles

[Volume average particle size]
20 ml of a sample and 1 ml of sodium alkyl ether sulfate are added to 50 ml of an electrolytic solution (trade name: ISOTON-II, manufactured by Beckman Coulter), and ultrasonic waves are applied using an ultrasonic disperser (trade name: UH-50, manufactured by STM). A sample for measurement was prepared by dispersing for 3 minutes at a frequency of 20 kHz. This sample for measurement was measured using a particle size distribution measuring device (trade name: Multisizer 3, manufactured by Beckman Coulter, Inc.) under the conditions of aperture diameter: 100 μm, number of measured particles: 50000 count, and volume particle size distribution of sample particles. From this, the volume average particle size was determined. Further, the coefficient of variation of the toner was calculated from the following formula based on the volume average particle diameter and its standard deviation.
Coefficient of variation = standard deviation / volume average particle size

[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 was heated at a heating rate of 10 ° C. per minute and a DSC curve was measured. did. 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 of 10 kgf / cm ² (9.8 × 10 ⁵ Pa) was applied and a sample 1 g was a die (nozzle diameter 1 mm, length). 1 mm), and heated at a heating rate of 6 ° C. per minute. The temperature at which half of the sample flowed out of the die was determined and used as the softening point.

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

Example 1
<Core particle production process>
400 parts of polyoxypropylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, 380 parts of polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane and terephthalic acid A polyester resin (glass transition point (Tg) 64 ° C., softening point (Tm) 95 ° C.) synthesized using 330 parts as a raw material monomer and 3 parts of dibutyltin oxide as a catalyst, and copper phthalocyanine (C.I. I. Pigment Blue 15: 3) was added and melt kneaded for 40 minutes in a kneader set at a temperature of 140 ° C. to prepare a master batch having a colorant concentration of 40% by weight. Here, polyoxypropylene (2.0) -2,2-bis (4-hydroxyphenyl) propane is an average of propylene oxide with respect to 1.0 mol of 2,2-bis (4-hydroxyphenyl) propane. It is a compound with 2.0 mol added. Polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane is an average of 2 ethylene oxides per 1.0 mol of 2,2-bis (4-hydroxyphenyl) propane. This is a compound added with 0.0 mol.

  Next, 77.5 parts of the same polyester resin (glass transition point (Tg) 64 ° C., softening point 95 ° C.) used for preparing the master batch, master batch prepared as described above (colorant concentration 40% by weight) ) 12.5 parts, 8 parts of a release agent (carnauba wax melting point 82 ° C.) and 2 parts of a charge control agent (Bontron E84, Orient Chemical Co., Ltd.) were mixed and dispersed in a Henschel mixer for 3 minutes to obtain a raw material. The obtained raw material was melt-kneaded and dispersed using a twin-screw extruder (trade name: PCM-30, manufactured by Ikegai Co., Ltd.) to prepare a resin kneaded product. The operating conditions of the twin screw extruder were a cylinder set temperature of 110 ° C., a barrel rotation speed of 300 revolutions per minute (300 rpm), and a raw material supply speed of 20 kg / hour. The obtained toner kneaded product was cooled with a cooling belt and then coarsely pulverized with a speed mill having a φ2 mm screen.

  The obtained coarsely pulverized product is pulverized by a type I jet mill, and further, fine powder and coarse powder are removed by an elbow jet classifier to obtain a core particle C having an average particle diameter B of 6.9 μm and a coefficient of variation of 22. It was.

<Fine resin particle and adhesion aid preparation process>
Styrene-methyl methacrylate copolymer fine particles (trade name: MP-5000, manufactured by Soken Chemical Co., Ltd., Tg 102 ° C.) having a volume average particle size of 0.4 μm were prepared. Moreover, ethanol was prepared as an adhesion aid.

<Coating process>
In a surface modification apparatus (trade name: Hybridization System NHS-1 type, manufactured by Nara Machinery Co., Ltd.) equipped with a two-fluid nozzle capable of spraying liquid in a container, 100 parts of core particles C and 5 parts of fine resin particles are added. After being charged and allowed to stay at a rotation speed of 8000 rpm for 10 minutes, compressed air is sent to the two-fluid nozzle, and adjustment is made so that ethanol as an adhesion aid is sprayed at 0.5 g / min. The entire surface of the particles was coated with fine resin particles.

  The core particles on which the coating layer was formed by coating fine resin particles on the entire surface of the core particles were lyophilized to obtain the toner of Example 1. The toner of Example 1 had a volume average particle size of 7.3 μm and a coefficient of variation of 25.

(Example 2)
A toner of Example 2 was obtained in the same manner as in Example 1 except that the fine resin particles and the adhesion auxiliary agent preparation step and the coating step were changed as follows. The toner of Example 2 had a volume average particle size of 7.3 μm and a coefficient of variation of 26.

<Fine resin particle and adhesion aid preparation process>
Styrene-methyl methacrylate copolymer fine particles having a volume average particle size of 0.4 μm (trade name: MP-5000, manufactured by Soken Chemical Co., Ltd., Tg 102 ° C.) 20 parts (solid content) and 80 parts of ethanol as an adhesion aid (Solid content) was stirred and mixed at 8000 rpm for 20 minutes using a homogenizer (trade name: Polytron PT-MR3100, manufactured by Kinematica), and the concentration of fine resin particles having a volume average particle size of 0.4 μm was 20% by weight. A coating solution was prepared.

<Coating process>
100 parts of core particles C are put into a surface reformer (trade name: Hybridization System NHS-1 type, manufactured by Nara Machinery Co., Ltd.) equipped with a two-fluid nozzle that can spray liquid in the container and stays at a rotation speed of 8000 rpm. Compressed air is sent to the two-fluid nozzle, and the coating fluid, which is a mixture of 20 parts of fine resin particles and 80 parts of ethanol (solid content), is sprayed from the two-fluid nozzle at a rate of 0.5 g / min. The fine resin particles were coated on the entire surface of the core particles by spraying for 50 minutes.

(Example 3)
Except that styrene-methyl methacrylate copolymer fine particles (Tg 102 ° C.) having a volume average particle size of 0.2 μm obtained by polymerizing styrene and methyl methacrylate were used as the fine resin particles, the same as in Example 1. Thus, a toner of Example 3 was obtained. The toner of Example 3 had a volume average particle size of 7.1 μm and a coefficient of variation of 25.

Example 4
Example 1 except that methyl methacrylate polymer fine particles (trade name: MP-1451, manufactured by Soken Chemical Co., Ltd., Tg 128 ° C.) having a volume average particle size of 0.15 μm were used as fine resin particles, A toner of Example 4 was obtained. The toner of Example 4 had a volume average particle size of 7.0 μm and a coefficient of variation of 25.

(Example 5)
A toner of Example 5 was obtained in the same manner as in Example 1 except that the core particle production process was changed as follows. The toner of Example 5 had a volume average particle size of 7.2 μm and a coefficient of variation of 24.

<Core particle production process>
790 parts of 1,4-butanediol, 440 parts of 1,6-hexanediol, 1500 parts of fumaric acid, 1 part of hydroquinone, and 2 parts of dibutyltin oxide are reacted to have a softening point of 110 ° C., the maximum peak of heat of fusion A crystalline polyester resin E (number average molecular weight: 4200, weight average molecular weight: 72000) having a temperature of 111 ° C. was obtained.

  Average using the same method as for core particle C, except that 10 parts of crystalline polyester resin E, 67.5 parts of the above polyester resin, 12.5 parts of masterbatch, 8 parts of release agent, and 2 parts of charge control agent are used. A core particle D having a particle size B of 6.9 μm and a variation coefficient of 22 was obtained.

(Example 6)
A toner of Example 6 was obtained in the same manner as in Example 5, except that styrene-butyl acrylate copolymer fine particles (Tg 80 ° C.) having a volume average particle size of 0.1 μm were used as the fine resin particles. The toner of Example 6 had a volume average particle size of 7.0 μm and a coefficient of variation of 24.

(Comparative Example 1)
A toner of Comparative Example 1 was obtained in the same manner as in Example 1 except that the coating process was changed as follows. The toner of Comparative Example 1 had a volume average particle size of 7.0 μm and a coefficient of variation of 26. Some of the toner of Comparative Example 1 had fine resin particles detached.

<Coating process>
100 parts of core particles and 5 parts of fine resin particles are put into a surface modification device (trade name: Hybridization System NHS-1 type, manufactured by Nara Machinery Co., Ltd.), and are allowed to stay for 10 minutes at a rotation speed of 8000 rpm. The fine resin particles were adhered to the core particles without spraying.

(Comparative Example 2)
A toner of Comparative Example 2 was obtained in the same manner as in Example 1 except that particles having a volume average particle diameter of 1.0 μm (Tg 128 ° C.) obtained by polymerizing methyl methacrylate were used as the fine resin particles. The toner of Comparative Example 2 had a volume average particle size of 7.0 μm and a coefficient of variation of 30. The fine resin particles were not fused to the core particles of the toner of Comparative Example 2.

  Table 1 shows the physical property values and the like of the toners of Examples and Comparative Examples produced as described above. “Particle” in the “spraying” section means fine resin particles.

The storability of the toners of Examples and Comparative Examples was evaluated as follows.
[Preservation evaluation]
After 100 g of toner was sealed in a plastic container and allowed to stand at 50 ° C. for 48 hours, the toner was taken out and passed through a # 100 mesh sieve. The weight of the toner remaining on the sieve was measured, and the remaining amount, which is the ratio of this weight to the total toner weight, was determined and evaluated according to the following criteria. A lower numerical value indicates that the toner does not block and the storage stability is better.
○: Good. The remaining amount is less than 10%.
X: Defect. The remaining amount is 10% or more.

  In addition, 100 parts of the toners of Examples and Comparative Examples obtained as described above were mixed with 0.7 part of silica particles having an average primary particle diameter of 20 nm hydrophobized with a silane coupling agent and 1 part of titanium oxide. did. Further, this externally added toner and a ferrite core carrier having a volume average particle diameter of 60 μm are mixed so that the concentration of the externally added toner is 7% by weight, thereby preparing a two-component developer having a toner concentration of 7% by weight. did. Using the obtained two-component developer, an image for evaluation was formed as follows, and the following evaluation was performed.

[Formation of evaluation image]
The obtained two-component developer was put into a developing device of a test printer obtained by removing a fixing device from a commercially available printer (trade name: LIBRE AR-S505, manufactured by Sharp Corporation), and was subjected to Japanese Industrial Standard (JIS). ) On the A4 size recording paper defined in P0138, the toner adhesion amount is adjusted to 0.6 mg / cm ^2, and the rectangular solid image portion 20 mm long and 50 mm wide is unfixed. Formed. An unfixed toner image formed was fixed by using an external fixing machine at a recording paper passing speed of 120 mm / sec (120 mm / sec) to form an evaluation image. For the external fixing machine, an oil-less fixing device taken out from a commercially available full-color copying machine (trade name: LIBRE AR-C260, manufactured by Sharp Corporation) is set so that the surface temperature of the heating roller can be set to an arbitrary value. A modified version was used. The oilless fixing device is a fixing device that performs fixing without applying a release agent such as silicone oil to a heating roller.

[High temperature offset resistance evaluation]
Whether or not the high temperature offset phenomenon has occurred by visually observing whether or not the toner image is retransferred from the heating roller to the white background portion to be the white background of the recording paper. It was judged. This operation is repeated by sequentially increasing the surface temperature of the heating roller from 130 ° C. to 220 ° C. by 5 ° C., and the maximum surface temperature of the heating roller that does not cause the high temperature offset phenomenon (hereinafter referred to as the maximum fixing temperature). Asked. Evaluation of high temperature offset resistance was performed according to the following criteria.
○: Good. Maximum fixing temperature is 200 ° C or higher.
X: Defect. Maximum fixing temperature is less than 200 ° C.

[Non-offset area evaluation]
Similarly to the evaluation of the high temperature offset resistance, the surface temperature of the heating roller is sequentially increased from 130 ° C. to 220 ° C. by 5 ° C. to form an image, and the low temperature offset phenomenon in which the toner image is not fixed on the recording paper, A non-offset region where no high temperature offset phenomenon in which the toner image is retransferred from the heating roller to the white background portion to be white background was examined to evaluate the offset resistance. The non-offset range is the lowest fixing temperature (° C) that is the lowest temperature of the heating roller that does not cause the low temperature offset phenomenon, and the highest fixing temperature (° C) that is the highest temperature of the surface of the heating roller that does not cause the high temperature offset phenomenon. It is obtained from the temperature difference. The non-offset area was evaluated according to the following criteria.
○: Good. Non-offset range is 25 ° C or higher.
X: Defect. Non-offset range is less than 25 ° C.

[Image density]
For the image formed when the surface temperature of the heating roller is 170 ° C., the reflection density meter (trade name: RD918, manufactured by Macbeth Co.) is used to measure the optical reflection density of the solid image portion. did. The image density was evaluated according to the following criteria.
○: Good. Image density is 1.40 or higher.
X: Defect. Image density is less than 1.40.

[Cleanability]
In the same manner as described above, after 1000 sheets of a chart with a printing rate of 5% were continuously printed, whether or not filming occurred on the surface of the photoreceptor was visually confirmed. The cleaning property was evaluated according to the following criteria.
○: Good. Filming has not occurred.
X: Defect. Filming has occurred.

[Comprehensive evaluation]
A total evaluation was performed based on the following criteria, combining the results of the storage stability, high temperature offset resistance evaluation, non-offset area evaluation, image density evaluation, and cleaning property.
○: Good. There are no items rated as bad (x).
X: Defect. There is one or more items evaluated as defective (x).
The above evaluation results are shown in Table 2.

  As shown in Table 2, the toners of Examples 1 to 6, which are the toners of the present invention, were superior to the toners of Comparative Examples 1 and 2 in storage stability, high-temperature offset resistance, and cleaning properties.

FIG. 6 is a process diagram illustrating a procedure of a toner manufacturing method according to an embodiment of the present invention. 1 is a cross-sectional view schematically showing a configuration of an image forming apparatus 1 using a developer of the present invention. It is sectional drawing which shows typically the structure of the developing means 14 using the developing agent of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Toner image forming means 3 Transfer means 4 Fixing means 5 Recording medium supply means 6 Ejecting means 11 Photosensitive drum 12 Charging means 13 Exposure unit 14 Developing means 15 Cleaning unit 20 Developing tank 20a Developing roller 20b Supply roller 20c Stirring Roller 21 Toner hopper 25 Intermediate transfer belt 26 Drive roller 27 Driven 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 feeding Paper tray 40 Discharge roller 41 Discharge tray

Claims (8)

A core particle obtained by pulverizing and classifying a composition containing a polyester resin as a binder resin, a colorant and other components, and a coating layer of fine resin particles formed on the surface of the core particle, A toner that is a coating layer in which a part of the fine resin particles forming the coating layer is fused with at least one of the core particles and the adjacent fine resin particles in the coating layer, and is subjected to lower alcohol spraying The surface of each particle is swollen or softened and brought into contact, and a part of the fine resin particles is fused to at least one of the core particles and the adjacent fine resin particles in the coating layer. And a styrene-methyl methacrylate copolymer or styrene-butyl acrylate copolymer having a volume average particle size of 0.05 μm or more and 0.5 μm or less. Toner wherein Rukoto using either polymer or methyl methacrylate. A manufacturing method for manufacturing the toner according to claim 1 , comprising 100 parts by weight of core particles obtained by pulverizing and classifying a composition including a polyester resin as a binder resin , a colorant and a colorant and other components. Then, 1 part by weight or more and 30 parts by weight or less of the fine resin particles are brought into contact with each other while the surface of each particle is swollen or softened under a lower alcohol spray , and a part of the fine resin particles are formed on the core particle surface. And a toner manufacturing method for forming a coating layer formed by fusing at least one of the adjacent fine resin particles in the coating layer, wherein the volume average particle size of the fine resin particles is 0.05 μm or more and 0.0. A toner comprising a styrene-methyl methacrylate copolymer, a styrene-butyl acrylate copolymer, or a methyl methacrylate having a size of 5 μm or less. Production method. The core particles are made into a core particle by a surface reformer comprising a container for containing the core particles and the fine resin particles therein, and a spraying means for spraying the lower alcohol into the container, and a stirring means for stirring the core particles in the container. The method for producing a toner according to claim 2 , wherein fine resin particles are adhered and fused. In a surface modification apparatus comprising a container for containing core particles and fine resin particles therein, and a spraying means for spraying a lower alcohol into the container, and a stirring means for stirring the core particles in the container. spraying device, method for producing a toner according to claim 2 or 3, characterized in that a spray for spraying means a mixture of lower alcohol and fine resin particles. The method for producing a toner according to claim 4 , wherein the lower alcohol is used in a ratio of 1 part by weight or more and 99 parts by weight or less with respect to 1 part by weight of the fine resin particles. Temperature in the vessel, method for producing a toner according to any one of claims 3-5, characterized in that is less than the glass transition point of the binder resin contained in the core particles. The method for producing a toner according to any one of claims 3 to 6 , wherein the lower alcohol is sprayed in a state where the core particles float in the container. A two-component developer comprising the toner according to claim 1 and a carrier.

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