JP2009223261A - Toner and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner excellent in cleaning property of a transfer residue toner on an intermediate transfer body during continuous printing at a high printing rate under an low temperature and low humidity environment, in an image forming method including a cleaning step of a transfer residue toner on an intermediate transfer body by use of a fixed charging brush. <P>SOLUTION: The toner is to be used for an image forming method employing a fixed charging brush that has a density of bristles ranging from 1.0×10<SP>6</SP>to 1.0×10<SP>9</SP>(number/m<SP>2</SP>) and an average diameter I (μm) of a single bristle ranging from 10 to 30 (μm), wherein the toner is characterized in that an average circularity R of the toner by a flow type particle image analyzer and a ratio N (%) of the number of particles having a diameter of not more than I/10 (μm) with respect to the number of whole particles satisfy 0.05≤(1-R)×N≤5.00 and 0.900≤R≤0.995. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrostatic image developing toner and an image forming method used for developing an electrostatic latent image in electrophotography and electrostatic recording. More specifically, the present invention relates to a toner used in an image recording apparatus that can be used for a copying machine, a printer, a facsimile, and the like, and an image forming method.

  In recent years, the technological trend of printers has progressed toward the miniaturization and speeding up of machines, and it has come to be used in various usages and environments regardless of whether it is a home or office.

  On the other hand, users are demanding printing on a wide variety of transfer materials. An intermediate transfer system that forms a multicolor image on an intermediate transfer body and transfers the multicolor image to an image fixing material at one time is a transfer material. Many have been adopted in that they can be transferred without choosing any of them.

  However, in the image forming method using the intermediate transfer member, the transfer efficiency generally tends to be lower than that in the image forming method not using the intermediate transfer member. Further, when the transfer residual toner on the intermediate transfer member cannot be sufficiently collected, an image adverse effect that the transfer residual toner is printed on the image tends to occur.

  In particular, when printing at a high printing rate in a low-temperature, low-humidity environment, a large amount of untransferred toner tends to remain on the intermediate transfer member, causing a large load on cleaning of the untransferred toner, resulting in image damage due to untransferred transfer toner. There was a tendency to be easy.

  Therefore, it is necessary to install a large-scale toner collection process, waste toner BOX, and the like in the machine, and from the viewpoint of downsizing, reduction of parts of the toner collection process and reduction of waste toner BOX have been studied.

  In order to solve the above problem, there has been proposed an image forming method in which the transfer residual toner is reversely charged using a charging roller and returned to the latent image carrier to perform cleaning (see, for example, Patent Documents 1 to 4).

  However, there is room for improvement in terms of further parts reduction, and the demand for toner at that time has become more severe. In particular, there is a demand for a toner having excellent cleaning properties on an intermediate transfer member even in a disadvantageous state of cleaning such as high-print continuous printing in a low-temperature and low-humidity environment.

JP-A-1-105980 JP-A-4-340564 Japanese Patent Laid-Open No. 5-29739 Japanese Patent Laid-Open No. 9-50167

  An object of the present invention is to provide a toner and an image forming method that solve the above-described problems.

  As a result of intensive studies, the present inventors have found that the above problem can be solved by the following configuration, and have completed the present invention.

That is, the present invention repeats the formation of the toner image on the first image carrier and the primary transfer of the toner image onto the second image carrier for the plurality of color toner images. After superimposing a plurality of color toner images on a carrier, the plurality of color toner images are collectively transferred to a transfer material to form a color image, and after the second transfer, the second image carrier The transfer residual toner remaining on the upper surface is transferred onto the first image carrier from the second image carrier by applying an electric charge by at least one fixed charging brush. The image bearing member is collected by a cleaning device, and the fixed charging brush has a bristle density of 1.0 × 10 ^{6 to} 1.0 × 10 ⁹ (lines / m ² ), The average diameter I (μm) of one brush of the brush is 10 to 30 (μm). In the toner used in the image forming method,
When the average circularity of the toner by the flow type particle image analyzer is R, and the ratio of the number of particles of I / 10 (μm) or less to the total number of particles is N (%),
0.05 ≦ (1-R) × N ≦ 5.00
0.900 ≦ R ≦ 0.995
The present invention relates to a toner characterized by satisfying

  According to the present invention, it is possible to provide a toner excellent in the cleaning property of the transfer residual toner on the intermediate transfer body even in high-print continuous printing in a low-temperature and low-humidity environment.

Hereinafter, the present invention will be described in detail with reference to embodiments of the present invention.
The toner of the present invention repeats the formation of a toner image on a first image carrier and the primary transfer of the toner image onto the second image carrier for a plurality of color toner images. After superimposing a plurality of color toner images on a carrier, the plurality of color toner images are collectively transferred to a transfer material to form a color image, and after the second transfer, the second image carrier The transfer residual toner remaining on the upper surface is transferred onto the first image carrier from the second image carrier by applying an electric charge by at least one fixed charging brush. The image bearing member is collected by a cleaning device, and the fixed charging brush has a bristle density of 1.0 × 10 ^{6 to} 1.0 × 10 ⁹ (lines / m ² ), An image having an average diameter I (μm) of one brush of 10 to 30 (μm) In the toner used in the image forming method,
When the average circularity of the toner by the flow type particle image analyzer is R, and the ratio of the number of particles of I / 10 (μm) or less to the total number of particles is N (%),
0.05 ≦ (1-R) × N ≦ 5.00
0.900 ≦ R ≦ 0.995
It is a great feature to satisfy this relationship.

  An example of an image forming apparatus using an image forming method to which the present invention is applied will be described below. This is shown in FIG. 1 and the configuration of the present invention will be described in more detail. However, this does not limit the present invention in any way. Absent.

(1) Example of Image Forming Apparatus FIG. 1 is a schematic configuration diagram of an example of an image forming apparatus according to the present invention.

  The image forming apparatus of the present example has a tandem configuration in which photosensitive drums that are a plurality of first image carriers 1 (latent image carriers) are vertically arranged in a linear direction, and the second image carrier 30 (intermediate transfer). An electrophotographic color (multicolor image) printer having a belt and a fixed charging brush 33 for charging the transfer residual toner on the second image carrier.

  In this example, an electrophotographic color printer of four colors of yellow, magenta, cyan, and black is given as an example, but the color, the number of colors, and the color order are not limited at all.

  In each of the first to fourth image forming units PY, PM, PC, and PBk, each photosensitive drum 1 that is driven to rotate forward is charged by a charging roller 2 to which a charging bias is applied from a power circuit (not shown) during the rotation process. The primary charging is uniformly performed to a predetermined polarity and potential.

  Light image exposures LY, LM, LC, and LBk, which are color separation component images of full-color images, respectively according to the image patterns of yellow, magenta, cyan, and black, are formed on the charging surface by the LED array device 3, respectively. Through the exposure process, an electrostatic latent image of image information is formed on each photosensitive drum 1.

  The electrostatic latent image is developed on each of the photosensitive drums 1 of the first to fourth image forming portions PY, PM, PC, and PBk through a developing process in which the electrostatic latent image is developed as a toner image by the developing device 4. In each of the electrophotographic processes, color toner images of yellow, magenta, cyan, and black, which are color separation component images of a full-color image, are formed at a predetermined sequence control timing.

  In each of the first to fourth image forming units PY, PM, PC, and PBk, yellow, magenta, cyan, and black color toner images are formed on the surface of each photosensitive drum 1.

  Next, the first to fourth images are respectively applied to the surface of the intermediate transfer belt 30 that is driven to rotate at the same speed as the photosensitive drum 1 in the clockwise direction indicated by the forward arrow in the forward rotation direction of each photosensitive drum 1. In the primary transfer portions of the forming portions PY, PM, PC, and PBk, the primary transfer roller is sequentially superposed and transferred (primary transfer) by a primary transfer bias applied from a power supply circuit (not shown) (primary transfer step).

  Through the primary transfer process, an unfixed full-color toner image (mirror image) is synthesized and formed on the surface of the intermediate transfer belt 30 that is rotationally driven.

  In each of the first to fourth image forming units PY, PM, PC, and PBk, the transfer residual toner remaining on each photosensitive drum 1 after the primary transfer of the toner image to the intermediate transfer belt 30 is cleaned by the blade cleaning device 6. It is removed by the blade and stored in the storage unit 6b in the apparatus 6 (primary transfer residual toner cleaning step).

  32 is a secondary transfer roller, and 32a is a counter roller.

  The counter roller 32a is disposed inside the intermediate transfer belt on the lower end side of the intermediate transfer belt 30, and the secondary transfer roller 32 sandwiches the intermediate transfer belt 30 between the counter roller 32a and the intermediate transfer belt 30. Is disposed in contact with the outer surface.

  A contact portion between the secondary transfer roller 32 and the intermediate transfer belt 30 is a secondary transfer portion.

  Reference numeral 40 denotes a paper feed cassette disposed in the lower part of the main body of the image forming apparatus, in which a transfer material P as a final recording medium is stacked and accommodated.

  The conveying means (pickup roller) 31 is driven at a predetermined sequence control timing to separate and feed one transfer material P in the paper feed cassette 40, and is fed to the secondary transfer unit at a predetermined timing.

  An unfixed full-color toner image synthesized and formed on the intermediate transfer belt 30 is transferred onto the surface of the transfer material P by a secondary transfer bias applied from a power supply circuit (not shown) to the secondary transfer roller 32 in the secondary transfer portion. Transfer is performed through a secondary transfer process in which batch transfer is performed.

  In the present invention, the untransferred toner remaining on the intermediate transfer belt 30 in the secondary transfer step is scattered and charged by the fixed charging brush 34 in contact with the intermediate transfer belt 30.

  In addition, it is preferable that the toner is further charged by using the charging roller 33 in combination because the entire toner can be more uniformly charged.

The density of the hair of the fixed charging brush used in the present invention is 1.0 × 10 ^{6 to} 1.0 × 10 ⁹ (lines / m ² ), and the average diameter I ( μm) is 10 to 30 (μm).

  The charged transfer residual toner is transferred from the intermediate transfer belt 30 to an arbitrary primary transfer roller 5 to an arbitrary drum by a primary transfer bias applied from a power supply circuit (not shown), and the cleaning blade 6a of the blade cleaning device 6 is transferred. Is sent to the waste toner box 6 in the image forming unit and stored.

  More preferably, the image forming unit that performs the secondary transfer residual toner cleaning step is appropriately changed.

  As a result, the waste toner is collected without being biased to the waste toner box 6 in each image forming unit, so that the apparatus can be further reduced in size (secondary transfer residual toner cleaning step).

  The transfer material P that has passed through the secondary transfer portion is separated from the surface of the intermediate transfer belt 30 and sent to the fixing device 7 by the transport belt 35.

  The unfixed full-color toner image on the transfer material P sent to the fixing device 7 is melted and fixed to the transfer material P by applying heat and pressure by the fixing device 7, passes through the sheet path 41, and the upper surface of the image forming apparatus main body. The sheet is discharged as a color image formed product onto a paper discharge tray 36 disposed in the above.

  By having the secondary transfer residual toner cleaning step as described above, it is possible to further reduce the size of the apparatus by reducing members such as a cleaning blade and a waste toner collection box for cleaning the intermediate transfer belt.

  Compared with the charging of the transfer residual toner with the conventional charging roller, the charging brush can more uniformly charge the toner by scattering the transfer residual toner. It can be expected that the cleaning performance is improved by reducing the amount of.

  However, since a member with a special structure called a fixed charging brush is used, and there is a tendency that the amount of residual toner after transfer tends to increase as in high-print continuous printing, the toner tends to adhere to the fixed charging brush and become contaminated. was there.

  For this reason, if high-print printing is continuously performed, there is a problem that sufficient and uniform charge cannot be imparted to the transfer residual toner by the charging brush, and there is a problem that cleaning is liable to occur, particularly in a low temperature and low humidity environment. It is easy to become.

  As a result of intensive studies, the present inventors have found that the above problem can be solved by using a toner having a special relationship with the brush diameter proposed in the present invention.

Specifically, when the average circularity of the toner by the flow type particle image analyzer is R, and the ratio of the number of fine particles of I / 10 (μm) or less to the total number of particles is N (%), The value of the formula obtained by multiplying N by the deviation (1-R) from the true sphere of circularity closely related to the secondary transfer efficiency,
0.05 ≦ (1-R) × N ≦ 5.00
0.900 ≦ R ≦ 0.995
By satisfying the above, the above problem is solved.

  Although the specific mechanism has not been clarified, the toner having the above characteristics has a reasonably small amount of toner adhering to the brush, so that cleaning failure may occur even in high-print continuous printing in a low-temperature and low-humidity environment. Predicts that it is less likely to occur.

  That is, toner fine particles having a size of 1/10 or less of the brush diameter have a large adhesion force to the brush and easily enter between the brushes. Therefore, it is considered that the transfer residual toner cannot be uniformly charged, and it is easy to cause a cleaning failure.

  On the other hand, when the amount of toner adhering to the brush is extremely small, it becomes impossible to uniformly charge the residual toner after transfer due to deterioration of the charging brush due to friction generated between the intermediate transfer member and the charging brush. It is thought that it becomes easy to cause.

  In the present invention, the relational expression (1-R) × N is preferably 0.05 ≦ (1-R) × N ≦ 5.00, more preferably 0.10 ≦ (1-R) × N ≦ 1.50. More preferably, 0.10 ≦ (1-R) × N ≦ 0.50.

  When the relational expression (1-R) × N is larger than 5.0, the secondary transfer residual toner having a particle diameter smaller than the brush diameter increases in high-printing printing in a low-temperature and low-humidity environment, resulting in cleaning failure due to member contamination. I predict it will be easier.

  When the relational expression (1-R) × N is smaller than 0.05, the secondary transfer residual toner having a particle diameter smaller than the brush diameter is remarkably reduced, and the brush and the intermediate transfer member are in direct contact with each other. As a result, it is predicted that cleaning failure is likely to occur due to deterioration of the charging brush due to friction between the intermediate transfer member and the charging brush.

  In the present invention, the average circularity of the toner particles is preferably in the range of 0.900 ≦ R ≦ 0.995, and more preferably 0.950 ≦ R ≦ 0.995.

  When the average circularity is smaller than 0.900, the amount of secondary transfer residual toner due to the decrease in secondary transfer efficiency becomes excessive, and a large amount of residual toner is charged with a brush. This makes it difficult to uniformly charge, making it difficult to obtain a sufficient cleaning effect.

  In the present invention, the method for controlling the particle ratio N is not particularly limited, and any conventionally known method can be adopted. For example, a method of thermally aggregating toner particles, air classification, wet classification, and the like can be appropriately selected and employed.

  The particle number ratio N (%) and circularity in the present invention were measured using a flow type particle image measuring apparatus “FPIA-2100 type” (manufactured by Toa Medical Electronics Co., Ltd.), and calculated as follows.

  The formulas used for calculating the equivalent circle diameter and the circularity are shown below.

  Here, the “particle projected area” is the area of the binarized toner particle image, and the “peripheral length of the particle projected image” is the length of the contour line obtained by connecting the edge points of the toner particle image. Define.

  The degree of circularity is an index indicating the degree of unevenness of the toner particles, and is 1.000 when the toner particles are completely spherical, and the degree of circularity becomes smaller as the surface shape becomes more complicated.

  As a specific measuring method, first, 10 ml of ion-exchanged water from which impure solids are removed in advance is prepared in a container. After adding a surfactant, preferably an alkyl benzene sulfonate, as a dispersant, 0.02 g of a measurement sample was further added and dispersed uniformly.

  As a means for dispersing, an ultrasonic disperser “Tetora 150 type” (manufactured by Nikka Ki Bios Co., Ltd.) was used for dispersion treatment for 2 minutes to obtain a dispersion for measurement. In that case, it cools suitably so that the temperature of this dispersion may not be 40 degreeC or more.

  In order to suppress variation in circularity, the installation environment of the apparatus is controlled at 23 ° C. ± 0.5 ° C. so that the temperature inside the flow type particle image analyzer FPIA-2100 is 26 to 27 ° C. Preferably, autofocusing was performed using 2 μm latex particles every 2 hours.

  To measure the circularity of the toner, the flow type particle image measuring device is used, the concentration of the dispersion is readjusted so that the toner concentration at the time of measurement is 3000 to 10,000 / μl, and 1000 or more toners are measured. To do. After the measurement, the average circularity of the toner was obtained from the result of the equivalent circle diameter of 0.6 to 400.0 μm using this data.

  Further, the ratio N (%) of the number of particles equal to or less than I / 10 (μm) to the total number of particles when the average diameter I (μm) of one brush of the fixed charging brush is obtained by the above measuring method. From the result of the obtained equivalent circle diameter, the ratio N of the number of particles with which the equivalent circle diameter is I / 10 (μm) or less was calculated.

The number average particle diameter D ₁ of the toner of the present invention is preferably 3.0 to 9.0 μm, more preferably 4.0 to 7.8 μm, and still more preferably 5.0 to 6.5 μm. is there.

  If it is smaller than 3.0 μm, the number of fine particles adhering to the fixed charging brush tends to increase, so that it tends to cause a transfer failure, and if it is larger than 9.0 μm, the fine line reproducibility tends to be poor.

The number average particle diameter D ₁ of the toner in the present invention is a precision particle size distribution measuring apparatus “Coulter Counter Multisizer 3” (registered trademark, manufactured by Beckman Coulter, Inc.) equipped with a 100 μm aperture tube. Measured with 25,000 effective measurement channels using the attached dedicated software “Beckman Coulter Multisizer 3 Version 3.51” (manufactured by Beckman Coulter, Inc.) for measurement condition setting and measurement data analysis Data were analyzed and calculated.

  As the electrolytic aqueous solution used for the measurement, special grade sodium chloride is dissolved in ion-exchanged water so as to have a concentration of about 1% by mass, for example, “ISOTON II” (manufactured by Beckman Coulter, Inc.) can be used.

  Prior to measurement and analysis, dedicated software was set up as follows.

  In the “Standard Measurement Method (SOM) Change Screen” of the dedicated software, set the total count in the control mode to 50000 particles, set the number of measurements once, and set the Kd value to “standard particles 10.0 μm” (Beckman Coulter, Inc.) Set the value obtained using The threshold and noise level are automatically set by pressing the threshold / noise level measurement button. Also, the current is set to 1600 μA, the gain is set to 2, the electrolyte is set to ISOTON II, and the aperture tube flash after measurement is checked.

  In the “pulse to particle size conversion setting screen” of the dedicated software, the bin interval is set to logarithmic particle size, the particle size bin is set to 256 particle size bin, and the particle size range is set to 2 μm to 60 μm.

  The specific measurement method is as follows.

  (1) About 200 ml of the electrolytic aqueous solution is put in a glass 250 ml round bottom beaker exclusively for Multisizer 3, set on a sample stand, and the stirrer rod is stirred counterclockwise at 24 rotations / second. Then, dirt and bubbles in the aperture tube are removed by the “aperture flush” function of the analysis software.

  (2) About 30 ml of the electrolytic aqueous solution is put in a glass 100 ml flat bottom beaker, and "Contaminone N" (nonionic surfactant, anionic surfactant, organic builder pH 7 precision measurement is used as a dispersant therein. About 0.3 ml of a diluted solution obtained by diluting a 10% by weight aqueous solution of a neutral detergent for washing a vessel (made by Wako Pure Chemical Industries, Ltd.) 3 times with ion-exchanged water is added.

  (3) Two oscillators with an oscillation frequency of 50 kHz are incorporated in a state where the phase is shifted by 180 degrees, and is placed in a water tank of an ultrasonic disperser “Ultrasonic Dissipation System Tetora 150” (manufactured by Nikki Bios Co., Ltd.) having an electrical output of 120 W. A fixed amount of ion-exchanged water is added, and about 2 ml of the above-mentioned Contaminone N is added to this water tank.

  (4) The beaker of (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. And the height position of a beaker is adjusted so that the resonance state of the liquid level of the electrolyte solution in a beaker may become the maximum.

  (5) In a state where the electrolytic aqueous solution in the beaker of (4) is irradiated with ultrasonic waves, about 10 mg of toner is added to the electrolytic aqueous solution little by little and dispersed. Then, the ultrasonic dispersion process is continued for another 60 seconds. In the ultrasonic dispersion, the temperature of the water tank is appropriately adjusted so as to be 10 ° C. or higher and 40 ° C. or lower.

  (6) To the round bottom beaker of (1) installed in the sample stand, the electrolyte solution of (5) in which the toner is dispersed is dropped using a pipette, and the measurement concentration is adjusted to about 5%. . The measurement is performed until the number of measured particles reaches 50,000.

(7) The measurement data subjected to analysis with the dedicated software included with the apparatus, to calculate the number average particle diameter D _1. The “average diameter” on the analysis / number statistics (arithmetic average) screen when the graph / number% is set in the dedicated software is the number average particle diameter D ₁ .

  In the present invention, the toner production method is not limited in any way, but more preferably, aggregated particles containing at least the resin fine particles and the colorant fine particles in a mixed solution containing at least the resin fine particles and the colorant fine particles. A toner production method (emulsion aggregation method) in which the aggregated particles are heated and fused after formation is a method for synthesizing the toner particles by aggregating the fine particles, and it is easy to suppress the generation of fine particles adhering to the fixed charging brush. This is preferable.

  Next, the emulsion aggregation method will be described below. In this case, the resin fine particles and the dispersant for the colorant particles used are aqueous media containing a surfactant. Examples of the aqueous medium include water such as distilled water and ion exchange water, and alcohols.

  The granulation of the fine particles in the emulsion aggregation method is preferably performed under high-speed shearing. In particular, in order to form fine particles, it is preferable to select a disperser equipped with a high-speed shearing mechanism, and among them, various types of homomixers, homogenizers, colloid mills, etc. More preferably, is used.

  The manufacturing method preferably includes at least a fine particle mixture preparation step and includes an aggregated particle formation step, a fusion step, and a cooling step. Furthermore, in this invention, another process can be included as needed.

  In the fine particle mixture preparation step, the binder resin fine particles, the colorant fine particles, and the like are uniformly dispersed and mixed in the mixed solution of the binder resin particle dispersion, the colorant particle dispersion, etc. in the aqueous medium. .

  In the aggregated particle forming step, fine particles of the binder resin, fine particles of the colorant and the like that are uniformly dispersed in the mixed solution are aggregated to form aggregated particles.

  In the fusing step, the resin in the aggregated particles melts and fuses to form color toner particles. In the fusing step, the pH of the aggregated particle dispersion may be changed as appropriate. By controlling the pH, the particle shape can be controlled.

  In the attached particle forming step, the fine particles contained in the fine particle dispersion added and mixed in the aggregated particle dispersion in which the aggregated particles are dispersed adhere to the surface of the aggregated particles as the mother particles. Particles are formed.

  When the adhered particle forming step is included before the fusing step, in the fusing step, the resin in the adhered particles is melted and fused to form electrostatic charge image developing toner particles.

  The distribution of the fine particles of the colorant in the aggregated particles finally becomes the distribution of the colorant particles in the toner particles. Therefore, the smaller the dispersion of the colorant particles, the more uniform the color development of the resulting toner particles. Improves.

  The combination of the fine particles of the colorant and the fine particles of the binder resin is not particularly limited and can be selected. The particle dispersion may contain fine particles such as fine particles of an internal additive, fine particles of a charge control agent, inorganic fine particles, organic fine particles, fine particles of a lubricant, fine particles of an abrasive, and the like.

  The fine particles that may be mixed are not particularly limited and may be appropriately selected depending on the purpose. In the present invention, these fine particles such as release agent fine particles may be dispersed in the resin particle dispersion or the colorant particle dispersion.

  As the surfactant, ionic or nonionic surfactants can be used. Specifically, alkylbenzene sulfonate, alkylphenyl sulfonate, alkyl naphthalene sulfonate, higher fatty acid salt, sulfate of higher fatty acid ester, sulfonic acid of higher fatty acid ester, etc. can be used as an anionic surfactant. . As the cationic activator, primary to tertiary amine salts, quaternary ammonium salts and the like can be used. Nonionic activators include polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester , Fatty acid alkylolamide and the like can be used. These dispersion stabilizing aids may be used alone or in combination of two or more. These dispersion stabilizing aids are preferably used in the range of 0.001 to 5.000 parts by mass with respect to 100 parts by mass of the main medium of the aqueous phase.

  In the emulsion aggregation method, in order to control the internal structure of the toner obtained by the growth due to the aggregation of the fine particles, it is preferable to sequentially add the resin fine particles while the aggregation of the fine particles is in progress. Thus, in the initial stage of particle aggregation, the resin fine particles enter the toner, and the resin fine particles added thereafter can cover the surface of the toner.

  The obtained toner is preferably washed with an acid such as hydrochloric acid, nitric acid, formic acid or acetic acid which makes the inorganic dispersion stabilizer water-soluble. This washing removes the inorganic dispersion stabilizer remaining on the toner surface.

  In the toner in which the inorganic dispersion stabilizer or the above-described surfactant remains on the toner surface, if the residual deposit is hygroscopic, the charging dependency on the environment is reduced. For this reason, it is preferable to remove such a dispersion stabilizer as much as possible to reduce the influence on the chargeability and powder flowability of the toner.

  The acid-treated or alkali-treated toner may be washed again with an alkaline water such as sodium hydroxide as necessary.

  As a result, when placed under a basic condition, a part of the ionic substance on the surface of the insolubilized toner is solubilized and removed, and the chargeability and powder flowability of the toner are improved.

  Further, when the toner is washed with acid or alkaline water, there is an advantage that the wax which has been released and adhered to the toner surface can be washed away. In addition to conditions such as pH at the time of washing, the number of times of washing, and temperature at the time of washing, washing is preferably performed using a stirrer, an ultrasonic dispersion device, or the like.

  Furthermore, if necessary, the toner for electrophotography can be obtained by performing filtration, centrifugation, etc., followed by drying, classification, and external addition.

[Binder resin in resin particles]
Examples of the monomer that is a constituent component of the binder resin contained in the resin fine particles in the present invention include vinyl monomers capable of radical polymerization. As the vinyl polymerizable monomer, a monofunctional polymerizable monomer or a polyfunctional polymerizable monomer can be used.

  Examples of the monofunctional polymerizable monomer include the following. Styrene; α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, p- styrene derivatives such as n-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-phenyl styrene; methyl acrylate, Ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, n-amyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n -Acrylic polymerizable monomers such as nonyl acrylate, cyclohexyl acrylate, benzyl acrylate, dimethyl phosphate ethyl acrylate, diethyl phosphate ethyl acrylate, dibutyl phosphate ethyl acrylate, 2-benzoyloxyethyl acrylate; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, tert-butyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, n-nonyl methacrylate, Diethyl phosphate ethyl methacrylate, dibutyl phosphate Methacrylic polymerizable monomers such as til methacrylate; methylene aliphatic monocarboxylic acid esters; vinyl esters such as vinyl acetate, vinyl propionate, vinyl acetate, vinyl benzoate, vinyl formate; vinyl methyl ether, vinyl ethyl ether, vinyl Vinyl ethers such as isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropyl ketone.

  Moreover, the following are also mentioned. Ethylenically unsaturated monoolefins such as ethylene, propylene and butylene; vinyl halides such as vinyl chloride, vinylidene chloride and vinyl fluoride; vinyl esters such as vinyl acetate and vinyl propionate; 2-vinylpyridine, 4-vinylpyridine, Monovinyl monomers such as nitrogen-containing vinyl compounds such as N-vinylpyrrolidone;

  The following are mentioned as a polyfunctional polymerizable monomer. Diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, 2,2 '-Bis (4- (acryloxy-diethoxy) phenyl) propane, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol Dimethacrylate, 1,3-bu Lenglycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2′-bis (4- (methacryloxy-diethoxy) phenyl) propane, 2,2′-bis ( 4- (methacryloxy / polyethoxy) phenyl) propane, trimethylolpropane trimethacrylate, tetramethylolmethane tetramethacrylate, divinylbenzene, divinylnaphthalene, divinyl ether.

  In the emulsion aggregation method, the above-mentioned monofunctional polymerizable monomers are used alone or in combination of two or more kinds, or the above-mentioned monofunctional polymerizable monomers and polyfunctional polymerizable monomers are combined. May be used. The polyfunctional polymerizable monomer can also be used as a crosslinking agent.

  A polyester resin can also be used as a binder resin for resin fine particles in the emulsion aggregation method. Of these, those having an acid value (according to JIS K 0070) in the range of 1 to 50 (KOH mg / g) are preferred, and those in the range of 3 to 30 are more preferred. If the acid value is less than 1, it is difficult to obtain a stable aqueous dispersion. On the other hand, if it exceeds 50, the amount of water absorbed by the toner increases, which is not preferable. The acid value of the polyester resin can be adjusted by changing the composition ratio of the acid component and the alcohol component or by neutralizing the acid value with alcohol.

  In the emulsion aggregation method, in order to produce fine particles using the above-mentioned polyester resin having an acid value, an oil phase in which the pigment is dispersed and the polyester resin is dissolved in an appropriate organic solvent is prepared, and a neutralizer is added thereto. Is added to ionize the carboxyl group of the polyester resin, and then this is added to an aqueous medium for phase inversion and the solvent is distilled off.

  In the oil phase, an internal substance such as a wax or a charge control agent may be dispersed as necessary. The fine particles obtained in this way are formed by preferentially gathering high acid value polyester on the particle surface and pushing wax or low acid value polyester into the inside of the particle.

  The polyester resin used as the binder resin is produced by subjecting a polyhydric alcohol component and a polyvalent carboxylic acid component as polymerization monomers to a polycondensation reaction in the presence of a catalyst, if necessary.

  As the polyhydric alcohol component of the polymerization monomer, for example, the following are used. Polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3,3) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2, 0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2,0) -polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene Diols such as (2,0) -polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane; ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, Isopentyl glycol, hydrogenated bisphenol A, 1,3-butane All, 1,4-butanediol, neopentyl glycol, xylylene glycol, 1,4-cyclohexanedimethanol, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, bis- (β-hydroxyethyl) terephthalate, tris- (Β-Hydroxyethyl) isocyanurate, 2,2,4-trimethylolpentane-1,3-diol. Furthermore, as a hydroxycarboxylic acid component, for example, p-oxybenzoic acid, vanillic acid, dimethylolpropionic acid, malic acid, tartaric acid, 5-hydroxyisophthalic acid and the like can be added.

  Examples of the polycarboxylic acid component include malonic acid, succinic acid, glutaric acid, dimer acid, phthalic acid, isophthalic acid, terephthalic acid, isophthalic acid dimethyl ester, terephthalic acid dimethyl ester, terephthalic acid monomethyl ester, and tetrahydroterephthalic acid. , Methyltetrahydrophthalic acid, hexahydrophthalic acid, dimethyltetrahydrophthalic acid, endomethylenehexahydrophthalic acid, naphthalenetetracarboxylic acid, diphenolic acid, trimellitic acid, pyromellitic acid, trimesic acid, cyclopentanedicarboxylic acid, 3, 3 ′, 4,4′-benzophenonetetracarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, 2,2-bis- (4-carboxyphenyl) propane, trimellitic anhydride and 4,4- Diaminophenyl meta Obtained from a trimerization reaction product of diimide carboxylic acid, tris- (β-carboxyethyl) isocyanurate, isocyanurate ring-containing polyimide carboxylic acid, tolylene diisocyanate, xylylene diisocyanate or isophorone diisocyanate and trimellitic anhydride Examples include isocyanate ring-containing polyimide carboxylic acid. These may be used alone or in admixture of two or more.

  Among these, when a trivalent or higher polyvalent carboxylic acid and a polyhydric alcohol are used, a crosslinked polyester resin is generated, and thus stability such as fixing strength and offset resistance can be improved.

  A desired polyester resin can be easily produced by polycondensation using these as raw materials by a conventionally known ordinary method.

  The binder resin used in the toner of the present invention is preferably a resin for color toners that is excellent in transparency and color developability. Furthermore, in terms of toner fixability and particle formability, at least the polyester resin obtained by the above method. Among them, two or more different Tg or acid values may be mixed.

  The binder resin used in the present invention may be combined with other resins in the polyester resin. Other resins include styrene resin, acrylic resin, styrene-acrylic resin, silicone resin, epoxy resin, diene resin, phenol resin, terpene resin, coumarin resin, amide resin, amideimide resin, butyral resin, urethane resin, ethylene Examples include vinyl acetate resin.

  In the present invention, the polyester resin in the toner material is dissolved in a soluble organic solvent.

  The organic solvent used depends on the constituent components of the polyester, but usually, hydrocarbons such as toluene, xylene and hexane, halogenated hydrocarbons such as methylene chloride, chloroform and dichloroethane, ethanol, butanol and benzyl alcohol ether And alcohols such as tetrahydrofuran, ethers, esters such as methyl acetate, ethyl acetate, butyl acetate and isopropyl acetate, and ketones such as acetone, methyl ethyl ketone, diisobutyl ketone, cyclohexanone and methylcyclohexanone. These organic solvents mainly dissolve the polyester resin, but the colorant and other additives need not be dissolved.

  The volume average particle size of the binder resin in the resin particle dispersion is preferably 1 μm or less, and more preferably 0.01 μm or more and 1.00 μm or less.

  If the volume average particle size exceeds 1.00 μm, the particle size distribution of toner particles obtained by agglomeration and fusion may be broadened, or free particles may be generated, leading to a decrease in toner performance and reliability.

  The volume average particle diameter can be measured with, for example, a laser diffraction particle size distribution measuring machine or a Coulter counter.

  The binder resin preferably has a glass transition temperature (Tg) measured by DSC (Differential Scanning Calorimetry) in the range of 40 to 70 ° C. This glass transition temperature can be adjusted by changing the composition ratio of the constituent monomers.

  The peak molecular weight of the binder resin is preferably in the range of 5000 to 30000. If the peak molecular weight is less than 5000, fine particles may not be obtained by drying, and the toner has too good meltability and color mixing between pixels occurs. On the other hand, if the peak molecular weight exceeds 30000, the oil phase becomes highly viscous, or the viscosity of the toner at the time of fixing becomes too high, and a low temperature offset occurs in the fixing step, which is not preferable.

  Further, when the Mw (weight average molecular weight) / Mn (number average molecular weight) of the binder resin in the resin fine particles exceeds 100, the molecular weight distribution of the binder resin becomes too wide, so that sufficient fixing is performed. It will disappear.

[Colorant]
The colorant used in the present invention is added together with the binder resin as a toner material and dispersed in the fine particles. Further, the colorant may be incorporated by heteroaggregation during the particle growth process. As the colorant, known organic pigments, inorganic pigments or dyes are used.

  Among the color toners used in the present invention, yellow toner is used as the colorant in the colorant particles. Y. 49, 65, 73, 74, 75, 97, 98, 111, 116, 130 are preferably included. Similarly, in magenta toner, P.I. R. 31, 32, 122, 146, 147, 150, 164, 170, 175, 176, 184, 185, 187, 188, 208, 210, 212, 213, 222, 238, 245, 253, 256, 258, 261, Preferably, at least one of 269 is included. For cyan toner, C.I. I. Pigment blue 15: 1, C.I. I. Pigment Blue 15: 3 is preferable. In the case of the black toner, a mixture of carbon black, metal complex salt, and the like can be given.

  By using the colorant in consideration of the charge control agent, the scattering of the image at the time of fixing is reduced although the mechanism is not clear.

  These colorants need to be contained in a ratio that can form a visible image having a sufficient density, and vary depending on the toner particle size, development amount, etc., but usually 1 per 100 parts by mass of toner. Thru | or 100 mass parts, Preferably it is the range of 2 thru | or 20 mass parts.

  The volume average particle size of the colorant is preferably 1 μm or less, more preferably 0.50 μm or less, and still more preferably 0.01 μm or more and 0.50 μm or less.

  When the volume average particle size exceeds 1 μm, the particle size distribution of the finally obtained color toner may be broadened, free particles may be easily generated, and the toner performance and reliability may be reduced. It may be easy to invite.

  On the other hand, by setting the volume average particle size to 1 μm or less, it is possible to improve the dispersion of the colorant in the agglomerated particles, to suppress the uneven distribution of the composition among the toner particles, and to suppress variations in toner performance and reliability. There is an advantage that it can be easily done.

  Further, by setting the volume average particle size to 0.50 μm or less, the color developability, color reproducibility, OHP permeability and the like of the color toner can be further improved.

  In addition, the said volume average particle diameter can be measured using a laser diffraction type particle size distribution analyzer etc., for example.

  Further, the content of the colorant in the aggregated particles is preferably 50% by mass or less, and more preferably 2% by mass or more and 20% by mass or less.

[Release agent]
Any releasing agent may be used as long as it has releasability. Specifically, for waxes and waxes, plant systems such as carnauba wax, cotton wax, wood wax, rice wax, etc. Animal waxes such as wax, beeswax and lanolin, mineral waxes such as ozokerite and cercin, and petroleum waxes such as paraffin, microcrystalline and petrolatum can be used.

  In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax and polyethylene wax, fatty acid amides such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, and chlorinated hydrocarbon, esters, Synthetic waxes such as ketones and ethers can also be used. In addition, as a low molecular weight crystalline polymer resin, a homopolymer or copolymer of polyacrylate such as poly n-stearyl methacrylate and poly n-lauryl methacrylate (for example, a copolymer of n-stearyl acrylate-ethyl methacrylate, etc.) And the like, and a crystalline polymer compound having a long-chain alkyl group as a side chain, such as petroleum wax or synthetic wax such as paraffin wax and microcrystalline wax is preferable.

  The volume average particle size of the release agent in the dispersion is preferably 2 μm or less, more preferably 0.1 to 1.5 μm.

  When the volume average particle diameter of the release agent in the dispersion exceeds 2 μm, the particle size distribution of the finally obtained electrostatic charge developing toner becomes wide, and free particles may be easily generated. In some cases, the reliability is likely to decrease.

  In the present invention, by adjusting the volume average particle diameter of the release agent in the dispersion to the above range, uneven distribution of the composition among the toner particles can be suppressed, and variation in toner performance and reliability can be suppressed low. There is an advantage that can be.

  In addition, the said volume average particle diameter can be measured using a laser diffraction type particle size distribution measuring machine, a centrifugal type particle size distribution measuring machine, etc., for example.

[Charge control agent]
In the present invention, a commonly used positively or negatively chargeable charge control agent may be added. As the charge control agent, a metal soap can be used in combination. Such metal soaps include aluminum tristearate, aluminum distearate, barium, calcium, lead and zinc stearate, or cobalt, manganese, lead and zinc linolenate, aluminum, calcium, cobalt octanoic acid Salts, calcium and cobalt oleates, zinc palmitate, calcium, cobalt, manganese, lead and zinc naphthenates, calcium, cobalt, manganese lead and zinc resins and the like can be used. In addition, a metal complex of an organic compound having a carboxyl group or a nitrogen-containing group, a metal-containing dye, nigrosine, and the like can be given. In addition, a compound selected from the group consisting of metal salts of benzoic acid, salicylic acid, alkylsalicylic acid or catechol, metal-containing bisazo dyes, tetraphenylborate derivatives, alkylpyridinium salts, and combinations of these as appropriate. Is also possible. Specifically, Spiron Black TRH (Hodogaya Chemical Co., Ltd.), T-77 (Hodogaya Chemical Co., Ltd.), Bontron S-34 (Orient Chemical Co., Ltd.), Bontron E-84 (Orient Chemical Co., Ltd.), Bontron Examples thereof include N-01 (manufactured by Orient Chemical Co., Ltd.), Copy Blue-PR (manufactured by Hoechst), a charge control resin such as a quaternary ammonium salt-containing resin and a polar resin containing a sulfur atom. The counter ion of the charge control agent is not particularly limited, and any one can be used. For example, there are hydrogen, lithium, sodium, potassium, ammonium, alkylammonium and the like.

  The charge control agent is used in an amount of 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight, based on 100 parts by weight of the toner base particles.

  When the addition amount is less than 0.01 parts by mass, the charging ability is not sufficiently obtained, and voids are likely to occur from the initial image. When the amount exceeds 10 parts by mass, dispersion of the charge control agent itself is poor and the retained charge amount becomes excessive, and the object of producing a toner that eliminates the peeling offset at the time of fixing cannot be achieved.

  If the toner of the present invention is a polymerization method, a charge control agent may be contained in either the water phase or the oil phase.

  An inorganic fine powder may be added as a fluidity improver to the toner particles of the present invention.

  Examples of the inorganic fine powder externally added to the toner particles of the present invention include fine powder such as silica fine powder, titanium oxide fine powder, alumina fine powder or double oxide fine powder thereof. Among the inorganic fine powders, silica fine powder and titanium oxide fine powder are preferable.

  Examples of the silica fine powder include dry silica or fumed silica produced by vapor phase oxidation of silicon halide, and wet silica produced from water glass.

As the inorganic fine powder, dry silica having less silanol groups on the surface and inside the silica fine powder and less Na ₂ O and SO ₃ ²⁻ is preferable.

  The dry silica may be a composite fine powder of silica and another metal oxide by using a metal halogen compound such as aluminum chloride or titanium chloride together with a silicon halogen compound in the production process.

  The inorganic fine powder is externally added to the toner particles in order to improve the fluidity of the toner and make the toner particles uniformly charged.

  Since the inorganic fine powder can be subjected to a hydrophobic treatment, the toner charge amount can be adjusted and the environmental stability can be improved. Therefore, it is preferable to use a hydrophobic treated inorganic fine powder. As treatment agents for the hydrophobic treatment of inorganic fine powder, unmodified silicone varnish, various modified silicone varnishes, unmodified silicone oil, various modified silicone oils, silane compounds, silane coupling agents, other organosilicon compounds, organotitanium Compounds. These treatment agents may be used alone or in combination.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to the examples. In addition, all the parts used in an Example show a mass part.

<Example 1>
[Preparation of resin dispersion A]
Styrene: 300 parts butyl acrylate: 80 parts acrylic acid: 8 parts dodecyl mercaptan: 4 parts The above components were mixed in advance and dissolved to prepare solution (a). On the other hand, 7 parts of nonionic surfactant (trade name: Novonil, Sanyo Kasei Co., Ltd.) and 10 parts of anionic surfactant (trade name: Neogen R, Daiichi Kogyo Seiyaku Co., Ltd.) are added to 520 parts of ion-exchanged water. Dissolved to prepare solution (b).
The solutions (a) and (b) were put into a flask, emulsified by dispersing, and slowly mixed for 10 minutes. Further, 50 parts of ion-exchanged water in which 3 parts of ammonium persulfate was dissolved was added to perform nitrogen substitution.

  Thereafter, while stirring the flask, the contents were heated in an oil bath until the content reached 70 ° C., and emulsion polymerization was continued for 6 hours.

  Then, this reaction liquid was cooled to room temperature, and the resin dispersion liquid A was obtained.

[Preparation of Colorant Dispersion A]
C. I. Pigment Blue 15: 3: 70 parts Anionic surfactant (trade name: Neogen, manufactured by Daiichi Kogyo Co., Ltd.): 3 parts Ion-exchanged water: 400 parts After the above components were mixed and dissolved, a homogenizer (manufactured by IKA, Ultra) Was used to obtain a colorant dispersion liquid A.

[Preparation of release agent dispersion A]
Polyethylene wax (trade name: POLYWAX655, melting point 93 ° C. manufactured by Toyo Petrolite Co., Ltd.): 100 parts anionic surfactant (trade name: Pionin A-45-D, manufactured by Takemoto Yushi Co., Ltd.): 2 parts Ion-exchanged water: 500 parts After the components are mixed and dissolved, they are dispersed using a homogenizer (IKA, Ultra Tarrax), then dispersed with a pressure discharge type homogenizer, and release agent fine particles (polyethylene wax) are dispersed. A release agent dispersion A was obtained.

[Toner Production Example 1]
Resin dispersion A: 300 parts Colorant dispersion A: 200 parts Release agent dispersion A: 100 parts Rosin-modified maleic acid (softening point 139 ° C.): 60 parts (8% by mass)
Cationic surfactant (trade name: Sanizol B50, manufactured by Kao Corporation): 3 parts Ion exchange water: 500 parts The above components were homogenized in a round bottom stainless steel flask (trade name: Ultra Turrax T50, manufactured by IKA). After mixing and dispersing to prepare a mixed solution, the mixture was heated to 50 ° C. with stirring in an oil bath for heating, and held at 50 ° C. for 30 minutes to form aggregated particles.

  When a part of the obtained aggregated particles was observed with an optical microscope, the volume average particle diameter of the aggregated particles was about 5.1 μm.

  50 parts of the resin dispersion A was gradually added to the liquid in which the aggregated particles were formed, and the mixture was further heated and stirred at 50 ° C. for 30 minutes to obtain an aggregated particle dispersion A.

  Next, 6 parts of sodium dodecylbenzenesulfonate (trade name: Neogen SC, manufactured by Daiichi Kogyo Co., Ltd.) as an anionic surfactant was added to the aggregated particle dispersion A and heated to 97 ° C. Further, sodium hydroxide was added as appropriate to keep the pH in the system at 4.0 or lower, and maintained for 7 hours to fuse the aggregated particles.

  Thereafter, it was cooled to 45 ° C. at a descending rate of 1.0 ° C./min, filtered, sufficiently washed with ion-exchanged water, and further filtered through a 400 mesh sieve. This was dried with a vacuum dryer to obtain toner particles A.

  The obtained toner particles A were classified using a multi-division classifier using the Coanda effect to obtain toner particles 1.

  To 100 parts of the toner particles 1 obtained, 2.0 parts of colloidal silica (manufactured by Nippon Aerosil Co., Ltd., R972) was added and mixed using a Henschel mixer to obtain toner 1. The physical properties of the obtained toner particles 1 are shown in Table 1.

<Examples 2 to 4>
By adding 2.0 parts of colloidal silica (manufactured by Nippon Aerosil Co., Ltd., R972) in the same manner as in Example 1 to those obtained by appropriately changing the classification conditions of the toner of Example 1, the mixture was mixed using a Henschel mixer. Toners 2 to 4 as shown in 1 were obtained.

<Example 5>
[Toner Production Example 2]
Resin dispersion A: 300 parts Colorant dispersion A: 200 parts Release agent dispersion A: 100 parts Rosin-modified maleic acid (softening point 139 ° C.): 60 parts (8% by mass)
Cationic surfactant (trade name: Sanizol B50, manufactured by Kao Corporation): 3 parts Ion exchange water: 500 parts The above components were homogenized in a round bottom stainless steel flask (trade name: Ultra Turrax T50, manufactured by IKA). The mixture was mixed and dispersed to prepare a mixed solution, and then heated to 50 ° C. with stirring in an oil bath for heating, and held at 50 ° C. for 30 minutes to form aggregated particles.

  When a part of the obtained aggregated particles was observed with an optical microscope, the volume average particle diameter of the aggregated particles was about 5.1 μm.

  50 parts of the resin dispersion A was gradually added to the liquid in which the aggregated particles were formed, and the mixture was further heated and stirred at 50 ° C. for 30 minutes to obtain an aggregated particle dispersion A.

  Next, 6 parts of sodium dodecylbenzenesulfonate (trade name: Neogen SC, manufactured by Daiichi Kogyo Co., Ltd.) as an anionic surfactant is added to the aggregated particle dispersion A and heated to 97 ° C. By appropriately adding, the pH in the system was kept at 7.0 or lower and kept for 7 hours to fuse the aggregated particles.

  Thereafter, it was cooled to 45 ° C. at a descending rate of 1.0 ° C./min, filtered, sufficiently washed with ion-exchanged water, and further filtered through a 400 mesh sieve. This was dried with a vacuum dryer to obtain toner particles B.

  The obtained toner particles A were classified using a multi-division classifier utilizing the Coanda effect to obtain toner particles 5.

  To 100 parts of the obtained toner particles 5, 2.0 parts of colloidal silica (manufactured by Nippon Aerosil Co., Ltd., R972) was added and mixed using a Henschel mixer to obtain toner 5. The physical properties of the obtained toner particles 5 are shown in Table 1.

<Example 6>
The following materials were mixed in advance, melt-kneaded with a biaxial extruder, the cooled kneaded product was roughly pulverized with a hammer mill, and the resulting finely pulverized product was classified to obtain toner particles 6.
-Binder resin 100 parts by mass [styrene-n-butyl acrylate copolymer resin (Mw = 30,000, Tg = 62 ° C.)]
・ C. I. Pigment Blue 15:35 parts by mass, 3 parts by mass of an aluminum compound of di-tertiary butylsalicylic acid [Orient Chemical Industries, Ltd .: Bontron E88]
Ester wax 6.0 parts by mass (behenyl behenate: maximum endothermic peak = 72 ° C., Mw = 700)
To the obtained toner particles, 2.0 parts of colloidal silica (manufactured by Nippon Aerosil Co., Ltd., R972) was added in the same manner as in Example 1 and mixed using a Henschel mixer to obtain toner 6.

<Comparative Example 1>
Toner 7 was obtained by appropriately changing the classification conditions of Example 1.

<Comparative Example 2>
Toner 8 was obtained by appropriately changing the classification conditions of Example 5.

<Comparative Example 3>
Toner 9 was obtained by appropriately changing the pulverization conditions of Example 5.

[Evaluation test]
The toner 1 was evaluated later. It was confirmed that even after printing a plurality of sheets with a high printing rate in a low-temperature and low-humidity environment, the image was not adversely affected.

  For toners 2 to 9, evaluation was performed in the same manner as in Example 1 except that the toner used was changed. The results are shown in Table 2 together with the results of Example 1.

  The specific evaluation method is shown below.

  An image was evaluated using a modified machine (process speed: 200 mm / sec, fixing temperature: 170 ° C.) obtained by modifying LBP-3700 (manufactured by HP) as an evaluation machine as shown in FIG.

  For the evaluation, four sets of cartridges filled with 150 g of each toner listed in Table 1 were prepared and mounted in four stations, respectively.

<Cleaning performance measurement method>
A4 paper (Xerox 75g) under normal temperature and normal humidity (N / N: temperature 23.5 ° C, humidity 60% RH) and low temperature and low humidity (L / L: temperature 15.0 ° C, humidity 10% RH) environment / M ² paper) is used to print a solid image having a length of 25 cm and a width of 20 cm from 5 cm from the tip to the longitudinal direction in which the toner paste amount is 0.45 mg / cm ² for each color.

An image defect (spotted, on line) in which a solid white image is output on the entire surface of A4 paper (Xerox 75 g / m ² paper) every 10 prints, and untransferred residual toner is printed on the solid white image The cleaning performance was evaluated from the number of occurrences.
A: It does not occur even when 300 sheets are printed.
B: Occurs with 200 sheets or more and less than 300 sheets.
C: Occurred with 100 sheets or more and less than 200 sheets.
D: Occurred with 50 sheets or more and less than 100 sheets.
E: Occurs with less than 50 sheets.

It is explanatory drawing of an example of the image forming apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Charging roller 3 Exposure apparatus 4 Developing apparatus 5 Primary transfer roller 6 Cleaning apparatus 6a Cleaning blade 7 Fixing apparatus 11 Drive motor 12 Gear train 30 Intermediate transfer belt 31 Pickup roller 32 Secondary transfer roller 33 Charging roller 34 Charging brush 35 Paper transport belt 36 Paper discharge unit

Claims (8)

The formation of a toner image on the first image carrier and the primary transfer of the toner image onto the second image carrier are repeated for a plurality of color toner images, and a plurality of colors are formed on the second image carrier. After the toner images are superimposed on each other, the plurality of color toner images are collectively transferred to a transfer material to form a color image, and the transfer residue remaining on the second image carrier after the secondary transfer is formed. The toner is transferred from the second image carrier onto the first image carrier by applying an electric charge with at least one fixed charging brush, and further the first image carrier is cleaned. And the density of the hair of the fixed charging brush is 1.0 × 10 ^{6 to} 1.0 × 10 ⁹ (lines / m ² ), Used in an image forming method having an average diameter I (μm) of 10 to 30 (μm). Toner
When the average circularity of the toner by the flow type particle image analyzer is R, and the ratio of the number of particles of I / 10 (μm) or less to the total number of particles is N (%),
0.05 ≦ (1-R) × N ≦ 5.00
0.900 ≦ R ≦ 0.995
A toner characterized by satisfying The relational expression (1-R) × N is
0.10 ≦ (1-R) × N ≦ 1.50
The toner according to claim 1, wherein: The relational expression (1-R) × N is
0.10 ≦ (1-R) × N ≦ 0.50
The toner according to claim 1, wherein:   The toner is obtained by forming aggregated particles containing at least the resin fine particles and the colorant particles in a mixed solution containing at least resin fine particles and colorant fine particles, and then heating and aggregating the aggregated particles. The toner according to claim 1, wherein the toner has toner particles to be produced. The formation of a toner image on the first image carrier and the primary transfer of the toner image onto the second image carrier are repeated for a plurality of color toner images, and a plurality of colors are formed on the second image carrier. After superimposing the toner images, the plurality of color toner images are collectively transferred to a transfer material to form a color image, and after the secondary transfer, the transfer residue remaining on the second image carrier is also transferred. The toner is transferred from the second image carrier onto the first image carrier by applying an electric charge with at least one fixed charging brush, and further the first image carrier is cleaned. And the density of the hair of the fixed charging brush is 1.0 × 10 ^{6 to} 1.0 × 10 ⁹ (lines / m ² ), In an image forming method having an average diameter I (μm) of 10 to 30 (μm) ,
When the average circularity of the toner by the flow type particle image analyzer is R, and the ratio of the number of particles of I / 10 (μm) or less to the total number of particles is N (%),
0.05 ≦ (1-R) × N ≦ 5.00
0.900 ≦ R ≦ 0.995
An image forming method characterized by satisfying the above. The relational expression (1-R) × N is
0.10 ≦ (1-R) × N ≦ 1.50
The image forming method according to claim 5, wherein: The relational expression (1-R) × N is
0.10 ≦ (1-R) × N ≦ 0.50
The image forming method according to claim 5, wherein:   The image forming method has a tandem configuration in which a plurality of developing devices are arranged in a linear direction, and the transfer residual toner remaining on the second image carrier is collected by a plurality of first image carrier cleaning devices. The image forming method according to claim 5, wherein the image forming method is an image forming method.

Images