JP5652501B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus used for electrophotography, electrostatic photography, and the like, and to an electrostatic charge image developing toner used for such an image forming apparatus.

  In recent years, the range of application of image forming methods such as electrophotography and electrostatic photography has been expanded, and the market demand for image quality has become higher. In particular, in office documents, in addition to the development of mapping technology and latent image forming technology for input, the types of character hieroglyphics are more abundant and finer at the time of output. Due to the spread and development, the reproducibility of a latent image with extremely high image quality that has few defects and unclearness in printed images is required. In particular, as a developer used in the case of a line image having an electrostatic charge image on an electrostatic charge image holding member constituting the image forming apparatus of 100 μm or less (about 300 dpi or more), a conventional toner having a large particle diameter has fine line reproducibility. In general, however, the line image is not clear enough.

  In particular, in an image forming apparatus such as an electrophotographic printer using a digital image signal, a latent image is formed by gathering a certain number of dot units, and the solid portion, the halftone portion, and the light portion have different dot densities. It is expressed by However, if the toner is not arranged faithfully in the dot unit and the mismatch between the position of the dot unit and the position of the actually placed toner occurs, this corresponds to the ratio of the dot density of the black portion and the white portion of the digital latent image. There is a problem that the gradation of the toner image cannot be obtained. Furthermore, when the resolution is improved by reducing the dot size in order to improve the image quality, a phenomenon faithful to the latent image formed from the minute dots becomes more difficult, and the resolution is high and the gradation is poor. There is no denying the tendency for images to lack sharpness.

  Furthermore, with the advent of blue lasers, it is expected that the dot size of electrostatic latent images will be further reduced in the future, and an image forming method corresponding to that is demanded.

  In view of this, there has been proposed a device intended to improve the image quality by improving the reproducibility of minute dots by regulating the particle size distribution of the developer. Patent Document 1 proposes a toner having an average particle size of 6 to 8 μm, and attempts to form a latent image of fine dots with high reproducibility by reducing the particle size. Patent Document 2 discloses a toner base particle containing a toner having a weight average particle diameter of 4 to 8 μm and further containing 17 to 60% by weight of toner base particles having a particle diameter of 5 μm or less. Patent Document 3 discloses a magnetic toner containing 17 to 60% by number of magnetic toner base particles having a particle size of 5 μm or less. Patent Document 4 discloses toner base particles in which the content of toner base particles having a particle size of 2.0 to 4.0 μm is 15 to 40% by number in the toner particle size distribution.

  Further, Patent Document 5 describes a toner in which particles of 5 μm or less are about 15 to 65% by number. Further, Patent Documents 6 and 7 disclose similar toners. Further, Patent Document 8 contains 17 to 60% by number of toner base particles having a particle size of 5 μm or less, 1 to 30% by number of toner base particles having a particle size of 8 to 12.7 μm, and 16 μm or more. A toner having a specific particle size distribution in a toner having a volume average particle diameter of 4 to 10 μm and a toner having a specific particle size distribution is described. Further, in Patent Document 9, in the toner particles having a 50% volume particle diameter of 2 to 8 μm, the number of toner particles having a particle diameter of “0.7 × 50% number particle diameter” or less is 10 number% or less. Is described.

  However, all of these toners contain a large amount of particles having a particle size of 3.56 μm or less exceeding the upper limit of the right side of the formula (3) in the present invention. In this relative relationship, it is a toner in which a relatively large amount of fine powder remains with respect to a toner having a predetermined particle diameter. In such a toner, the ratio of fine powder is still large, and the following problems remain.

  Further, in recent years, life extension and high-speed printing have been demanded along with market demand for image quality. However, these required characteristics have not been sufficiently satisfied with the conventional toner. If there is a lot of fine powder like conventional toner, the fine powder will contaminate the member with continuous printing, the charge imparting ability to the toner will be reduced and the image will be distorted, and if it is introduced into a high speed printer, toner scattering will be noticeable There was also a problem.

  In order to provide high image printing, the toner particle size distribution needs to be sharp. This is because when the coarse particles are contained, the toner charge amount distribution becomes broad and a phenomenon called “selective development” occurs. “Selective development” is a phenomenon in which, when the toner charge amount distribution is broad, only the toner having the charge amount necessary for development at the time of copying is developed and consumed. Therefore, a good image can be obtained at the initial stage of copying, but the density gradually decreases as the copying continues, and the toner particle size increases, resulting in a rough image. Such a phenomenon is said to be inferior in selective developability. Furthermore, the coarse powder having a low charge amount tends to significantly reduce the guaranteed life number. Patent Document 10 discloses a toner having a large number of coarse powders having a number variation coefficient of 24.2%. Such a toner is not suitable for stably providing a high-resolution image. Further, Patent Document 11 does not indicate that the particle size distribution is sharp.

  Furthermore, it is necessary to pay attention to toner transfer characteristics in order to provide high-quality printing. The toner having high transfer characteristics refers to toner having high transfer efficiency of toner particles on the photosensitive member to the intermediate transfer drum or paper, or high transfer efficiency from the intermediate transfer drum to paper. Patent Documents 12 to 14 disclose pulverized toner that does not have a high average circularity from the viewpoint of the manufacturing process, which is insufficient to provide high-quality printing.

  Here, the toner developed into the electrostatic latent image on the electrostatic image holding member in the electrophotographic apparatus is transferred to a printed matter such as paper. In some cases, the image is not transferred directly from the electrostatic charge image holding member to the paper but is transferred via an intermediate transfer member. In this transfer step, the toner is not completely transferred from the electrostatic charge image holding member, and a small amount becomes a transfer residual toner and remains on the electrostatic charge image holding member. Therefore, after the transfer process, a cleaning process for removing the untransferred toner from the electrostatic charge image holding member is required.

  Conventionally, many cleaning blade methods have been used for such a cleaning process. That is, a cleaning blade formed of a material such as urethane rubber having a relatively low elastic modulus is brought into contact with the electrostatic charge image holding member, and the transfer residual toner is scraped off by relative movement of the cleaning blade and the electrostatic charge image holding member. . However, the leading edge of the cleaning blade abuts against the electrostatic charge image holding member and blocks the transfer residual toner. The leading edge ridge line is elastically deformed with the movement of the electrostatic charge image holding member in a state of being attached to the electrostatic charge image holding member due to the static frictional resistance force with the electrostatic charge image holding member, and the elastic repulsive force reduces the static frictional resistance force. When it exceeds, it is released and returns to its original shape. Further, the micro-vibration by the above-described process of repeating the elastic deformation once again with the electrostatic charge image holding member in the returned state is repeated. This phenomenon is called “stick and slip”.

  Even if stick-and-slip occurs, the clogged toner remaining after transfer does not leak from the gap between the cleaning blade and the electrostatic charge image holding member, and is used for toner cleaning. It is sometimes difficult to completely dampen particles that are slippery, such as particles with high circularity.

  Complete cleaning of small particles requires strict control of the position accuracy of the parts. Further, if many small particles are contained as compared with the average particle diameter, there is a high possibility that the transfer residual toner slips through the cleaning blade. In recent years, there has been a shift from pulverized toner to wet toner, but compared to pulverized toner, wet toner is easy to slip through because of its smooth surface and high average circularity. Further, in recent years, many toners having a high average circularity with a smooth surface obtained by heat and mechanical treatment have appeared as pulverized toners, and they are easily slipped through. Accordingly, the present situation is that an image forming apparatus in which toner particles are difficult to slip through is increasingly desired.

  Regarding the stick-and-slip phenomenon, the vibration width and vibration cycle are static friction resistance force and dynamic friction resistance force between the cleaning blade and the electrostatic charge image holding member (related to the speed at which the cleaning blade returns to its original shape). Depends on. Depending on the vibration width and vibration cycle, toner particles having a specific particle size, shape, and ease of slipping may be particularly easily slipped through. In this way, it is extremely difficult to theoretically handle the phenomenon that a particular particle is particularly easy to slip through, and how the toner, electrostatic charge image holding member, and cleaning blade can be made difficult to slip through. There was not enough knowledge yet.

  On the other hand, it is necessary to provide a technology with a stable cleaning performance in the market demand for reducing the particle size of the toner for high resolution. Further, as described above, wet toner and pulverized toner with a smooth surface are required. With the advent, the need has become stronger, but there was not enough technology.

JP-A-2-284158 JP-A-5-119530 JP-A-1-221755 JP-A-6-289648 JP 2001-134005 A Japanese Patent Laid-Open No. 11-147331 JP 2001-175024 A JP-A-2-000877 JP 2004-045948 A JP 2003-255567 A WO2004-088431 Japanese Patent Laid-Open No. 7-098521 JP 2006-091175 A JP 2006-119616 A

  The present invention has been made in view of the above-mentioned background art, and its problem is that the cleaning performance is stable, the occurrence of contamination on the parts in the apparatus due to poor cleaning, the occurrence of defective images, etc., and long-term use. However, it is an object of the present invention to provide an image forming apparatus in which the above-described problems are unlikely to occur, the image quality is good, and the image stability is excellent.

  As a result of intensive studies to solve the above problems, the present inventor has obtained only toner particles having a specific particle size and shape in a cleaning process in which toner, an electrostatic charge image holding member, and a cleaning blade are present, or Only the toner having a specific particle size distribution is noticed that there is a phenomenon that it is more difficult to slip through, and when the specific relational expression regarding the toner particle size is satisfied, the above problem can be solved and the present invention has been completed. . Furthermore, paying attention to the dynamic friction coefficient of the electrostatic charge image holding member, it has been found that by combining the toner form, a more stable cleaning performance can be exhibited, and the present invention has been completed.

That is, the present invention includes a developing process for attaching toner to the electrostatic image on the surface of the electrostatic charge image holding member, a transfer process for transferring the toner on the electrostatic charge image holding member to a transfer material, and a static process in the transfer process. An image forming apparatus having a cleaning process for cleaning the transfer residual toner remaining on the charge image holding member, wherein the toner used in the development process satisfies all of the following (1) to (4): Further, in the cleaning step, the image forming apparatus is characterized in that a cleaning blade is brought into contact with the electrostatic charge image holding member to clean the transfer residual toner.
(1) The volume median diameter (Dv50) is 4.0 μm or more and 7.0 μm or less.
(2) The average circularity is 0.93 or more.
(3) The relationship between the volume median diameter (Dv50) of toner and the number% (Dns) of toner having a particle diameter of 2.00 μm to 3.56 μm satisfies Dns ≦ 0.233EXP (17.3 / Dv50).
(4) The number variation coefficient is 24.0% or less.

  The present invention also relates to an electrostatic image developing toner used in the above-mentioned image forming apparatus.

The present invention also includes a development step for attaching toner to the electrostatic image on the surface of the electrostatic charge image holding member, a transfer step for transferring the toner on the electrostatic charge image holding member to a transfer material, and a transfer step. A toner used in an image forming apparatus having a cleaning step of cleaning a transfer residual toner remaining on an electrostatic charge image holding member by bringing a cleaning blade into contact with the electrostatic charge image holding member. To (4) an electrostatic charge image developing toner characterized by satisfying all of the above.
(1) The volume median diameter (Dv50) is 4.0 μm or more and 7.0 μm or less.
(2) The average circularity is 0.93 or more.
(3) The relationship between the volume median diameter (Dv50) of toner and the number% (Dns) of toner having a particle diameter of 2.00 μm to 3.56 μm satisfies Dns ≦ 0.233EXP (17.3 / Dv50).
(4) The number variation coefficient is 24.0% or less.

  According to the present invention, there is provided an image forming apparatus that suppresses the occurrence of stains and image defects on the parts in the apparatus due to poor cleaning, is less likely to cause the above problems even when used for a long period of time, and has excellent image stability. be able to.

FIG. 2 is a schematic view illustrating an example of a non-magnetic one-component toner developing device used in the image forming apparatus of the present invention.

  Hereinafter, the present invention will be described. However, the present invention is not limited to the following embodiments, and can be arbitrarily modified and implemented.

  The image forming apparatus of the present invention uses toner that satisfies the above (1) to (4), and the method for producing the toner is not particularly limited. Furthermore, what is necessary is just to employ | adopt the structure demonstrated below arbitrarily.

The toner used in the image forming apparatus of the present invention satisfies all of the following (1) to (4).
(1) The volume median diameter (Dv50) is 4.0 μm or more and 7.0 μm or less.
(2) The average circularity is 0.93 or more.
(3) The relationship between the volume median diameter (Dv50) of toner and the number% (Dns) of toner having a particle diameter of 2.00 μm to 3.56 μm satisfies Dns ≦ 0.233EXP (17.3 / Dv50).
(4) The number variation coefficient is 24.0% or less.

Regarding (1) The volume median diameter (Dv50) of the toner is measured by the method described in the Examples and is defined as the value measured as such. When the toner in the present invention is one in which an external additive is fixed or adhered to the surface of toner base particles, it is measured as a measurement sample. Similarly, the average circularity, the number% (Dns) of toner having a particle size of 2.00 μm to 3.56 μm, and the number variation coefficient, which will be described later, are similarly fixed or adhered to the surface of the toner base particles. If it is a sample, measure it as a measurement sample.

  The Dv50 of the toner of the present invention is 4.0 μm or more and 7.0 μm or less. Within this range, a high-quality image can be sufficiently provided. In order to give a high-quality image, the effect is more remarkable when the thickness is 6.8 μm or less. Moreover, it is preferable that it is 4.5 micrometers or more from a viewpoint of reducing the generation amount of a fine powder, It is still more preferable that it is 5.0 micrometers or more, It is especially more preferable that it is 5.3 micrometers or more.

Regarding (2) The average circularity of the toner is measured by the method described in the examples, and is defined as that measured. The average circularity of the toner of the present invention is 0.93 or more, and preferably 0.94 or more. In general, toner with a high degree of circularity has good transfer efficiency. Since the spherical toner having a high degree of circularity is less likely to get caught between toners or various members, the mechanical share at the charging roller is small, and the surface shape change is slight. Further, since the fluidity of the toner base itself is high, even if the amount of the externally added inorganic powder changes, the fluidity hardly changes greatly. As described above, the spherical toner has a form factor with less toner deterioration. Further, since it is excellent in releasability from the photosensitive drum, the transfer efficiency is excellent, it is possible to secure a sufficient image density and to reduce the residual toner. For these reasons, it is desirable to use toner having a high degree of circularity as the toner used in the high-speed printer.

  However, toner having a high average circularity tends to increase the weakly charged toner ratio WST [%] measured by the E-SPART analyzer, and toner scattering may be deteriorated. Furthermore, when the transfer residual toner is scraped off with a cleaning blade, the cleaning blade is likely to pass through, which may cause the image to become dirty. In the case of high-speed printing, this phenomenon becomes more remarkable. Therefore, the average circularity of the toner of the present invention is preferably 0.98 or less, more preferably 0.96 or less.

  In addition, toner with a small particle size and high circularity is difficult to scrape off with a cleaning blade, and the toner can easily pass through the cleaning blade. Therefore, the particle size distribution should be controlled according to the circularity. Is important.

Regarding (3) The number% (Dns) of toner having a toner particle size of 2.00 μm or more and 3.56 μm or less is measured by the method described in Examples and is defined as that measured. The toner of the present invention has a relationship between the volume median diameter (Dv50) of toner and the number% (Dns) of toner having a particle size of 2.00 μm to 3.56 μm.
Dns ≦ 0.233EXP (17.3 / Dv50)
Meet. In the present invention, “EXP” indicates “Exponential”. That is, the base of the natural logarithm, and the right side is the exponent.

  The purpose of this relational expression is that the amount of fine powder increases as the volume median diameter (Dv) of the toner decreases, and when the Dv is 4.5 μm or less, the value of Dv becomes the particle size. In order to approach the region of 2.00 μm or more and 3.56 μm or less, the value of Dns increases exponentially. Such an area of 2.00 μm or more and 3.56 μm or less is an area expressed by a specified channel of Multisizer III manufactured by Coulter Counter.

  In the present invention, particles included in the particle diameter range of 2.00 μm to 3.56 μm are particle size regions that should be specifically excluded in the region of the volume median diameter of toner particles of 4.0 to 7.0 μm. The basis for this follows experimental results. The toner of the present invention satisfying the condition (3) of the particle size distribution provides high image quality, and is less contaminated even when a high-speed printer is used, and afterimage (ghost) and blur (solid followability). And has excellent cleaning properties. In addition, since the charge amount distribution is very sharp because the particle size distribution is sharp, particles with a small charge amount do not cause the white background portion of the image to be smeared or scattered to stain the inside of the apparatus, Particles having a large charge amount do not develop and do not adhere to members such as a layer regulating blade or a roller and cause image defects such as streaks and blurring.

  That is, the amount of fine powder affects the image with the above relational expression as a boundary. When the value of Dns exceeds the right side, the fine powder causes a defect in the image. For example, as shown in FIG. 4, fine powder may accumulate on the cleaning blade, and afterimages, blurring, dirt, and the like may occur as image defects.

  Since the image forming apparatus is designed to transfer particles having a specific charge amount, first, in electrostatic development, the particles having the specific charge amount are preferentially transferred to the OPC. Particles exceeding the specific charge amount may adhere to the member or the like and become contaminated, or the fluidity may be deteriorated. On the other hand, particles that do not satisfy the specific charge amount may accumulate in the cartridge and contaminate members and the like.

  Here, the toner charge amount correlates with the particle size of the toner when the toner composition is the same. Generally, the smaller the particle size, the higher the charge amount per unit weight, and the larger the charge amount, the smaller the charge amount per unit weight. Become. That is, if there is a large amount of toner having a small particle size, the charge amount becomes too high, and this causes adhesion to a member or the like and deterioration of toner fluidity. In the present invention, this toner is specified to be 3.56 μm or less. This 3.56 μm is a value defined for the channel of the measuring apparatus. On the other hand, the lower limit value was set to 2.00 μm because of the measurement limit of the measuring apparatus.

  In addition, a toner in which the relationship between Dv50 and Dns satisfies Dns ≦ 0.110EXP (19.9 / Dv50) is preferable. On the other hand, it is preferable that the relationship between Dv50 and Dns satisfies 0.0517EXP (22.4 / Dv50) ≦ Dns from the viewpoint of producing with good yield.

  Further, a toner having a Dns of 6% by number or less is preferable in that it provides a higher quality image and hardly contaminates the image forming apparatus. Further, it is more preferable that the above-mentioned preferable particle diameter range of Dv50, for example, the conditions “Dv50 is 4.5 μm or more” and “Dns is 6% by number or less” are satisfied in combination. Within this range, it is possible to provide a high-quality image or a toner that hardly contaminates the image forming apparatus without reducing the yield from the viewpoint of production.

Regarding (4): The number variation coefficient (%) is measured by the method described in the examples and is defined as that measured. The number variation coefficient of the toner used in the present invention is 24.0% or less, preferably 22% or less, more preferably 20% or less, and still more preferably 19% or less. Generally, when the value of the number variation coefficient is high, the distribution of the charge amount becomes broad, and an image defect may be caused due to poor charging. Furthermore, contamination due to adhesion to the toner member or the like, or contamination due to scattering may be induced. Therefore, the number variation coefficient is preferably low. On the other hand, from an industrial standpoint, the number variation coefficient is preferably 0% or more, and more preferably 5% or more.

  The toner used in the present invention must satisfy all of the above (1) to (4). Conventional toners do not satisfy any of (1) to (4). The reason was as follows. That is, when trying to reduce the fine powder as much as possible (when satisfying (3)), coarse powder is generated and the number variation coefficient becomes large (does not satisfy (4)). Further, if the toner is made circular by physical impact (when (2) is satisfied), it causes the generation of fine powder (not satisfying (3)). When trying to round the toner by thermal fusion (when (2) is satisfied), the particles are fused with each other and coarse powder is generated ((4) is not satisfied). ).

  The toner used in the present invention provides high image quality, has little contamination even when a high-speed printer is used, suppresses afterimage (ghost) and blurring (solid followability), and has excellent cleaning properties. In addition, since the charge amount distribution is very sharp because the particle size distribution is sharp, particles with a small charge amount do not cause the white background portion of the image to be smeared or scattered to stain the inside of the apparatus, Particles having a large charge amount do not develop and do not adhere to members such as a layer regulating blade or a roller and cause image defects such as streaks and blurring.

  The toner used in the present invention has a very sharp charge amount distribution as compared with conventional toners. The charge amount distribution has a correlation with the particle size distribution of the toner. When the toner has a broad particle size distribution like a conventional toner, the charge amount distribution is also broad. When the charge amount distribution becomes broad, the ratio of particles with low charge or particles with high charge that cannot be controlled by the developing conditions of the toner device increases, causing various image defects. For example, particles with a small charge amount cause stains on the white background of the image or scatter in the apparatus, and particles with a large charge amount are not developed and are layer regulating blades in the developing tank. And accumulated in members such as rollers and cause image defects such as streaks and fading due to fusion.

  In the development process design in the image forming apparatus, the development process conditions are set so as to conform to the average value of the toner charge amount. The apparatus causes image defects such as scattering, streaks, and fading, and the matching with the apparatus is not good. On the other hand, if the charge amount distribution is sharp as in the present invention, the developability can be controlled by bias adjustment or the like, and a clear image can be given without contaminating the members of the image forming apparatus. is there.

  Since the toner of the present invention has a sharp charge amount distribution, the contamination (toner scattering) in the image forming apparatus caused by poorly charged toner is very small. This is particularly effective in a high-speed type image forming apparatus in which the development process speed for the electrostatic latent image carrier is 80 mm / second or more. The effect is exhibited in an image forming apparatus that is preferably 90 mm / second or more, more preferably 100 mm / second or more, and even more preferably 120 mm / second or more.

  Further, since the toner of the present invention has a sharp charge amount distribution, the developability is very good, and there are very few toner particles that accumulate without being developed. The effect is exhibited in the apparatus. Specifically, a toner used in an image forming apparatus that satisfies the following formula (5) is preferable in order to sufficiently exhibit the above-described effects of the present invention.

(5) Guaranteed lifetime number of sheets (sheets) x printing rate ≧ 400 (sheets) of the developer filled with developer
In the formula (5), “printing rate” is represented by a value obtained by dividing the sum of the printed portion areas by the total area of the printing medium in the printed matter for determining the guaranteed life number as the performance of the image forming apparatus. The “print rate” of the print% of “5%” is “0.05”.

  Furthermore, since the toner of the present invention has a very sharp particle size distribution, the reproducibility of the latent image is very good. Therefore, the effect of the present invention is sufficiently exerted particularly when used in an image forming apparatus having a resolution of 600 dpi or more for the electrostatic latent image carrier.

<Configuration of toner>
The toner used in the image forming apparatus of the present invention is configured by appropriately selecting a binder resin, a colorant, a wax, an external additive, and the like.

  The binder resin employed in the toner used in the image forming apparatus of the present invention may be appropriately selected from those known to be usable in toner. For example, styrene resin, vinyl chloride resin, rosin modified maleic acid resin, phenol resin, epoxy resin, saturated or unsaturated polyester resin, polyethylene resin, polypropylene resin, ionomer resin, polyurethane resin, silicone resin, ketone resin, Ethylene-acrylate copolymer, xylene resin, polyvinyl butyral resin, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-anhydrous malein An acid copolymer etc. can be mentioned. These resins can be used alone or in combination.

  The colorant constituting the toner used in the image forming apparatus of the present invention may be appropriately selected from those known to be usable for toner. For example, yellow pigments, magenta pigments, and cyan pigments shown below can be used. As black pigments, carbon black or a mixture of the following yellow pigments / magenta pigments / cyan pigments toned to black is used. .

  Among these, carbon black as a black pigment exists as an aggregate of very fine primary particles, and when dispersed as a pigment dispersion, coarsening of particles due to reaggregation tends to occur. The degree of reagglomeration of carbon black particles correlates with the amount of impurities contained in carbon black (the degree of residual undecomposed organic matter). If there are many impurities, coarsening due to reaggregation after dispersion tends to be severe. showed that. As a quantitative evaluation of the amount of impurities, the ultraviolet absorbance of the toluene extract of carbon black measured by the following method is preferably 0.05 or less, and more preferably 0.03 or less. Generally, carbon black produced by the channel method tends to have a large amount of impurities, and therefore, carbon black produced by the furnace method is preferred as the carbon black in the present invention.

  The ultraviolet absorbance (λc) of carbon black is determined by the following method. First, 3 g of carbon black was sufficiently dispersed and mixed in 30 mL of toluene. Filter using 5C filter paper. Thereafter, the filtrate was put in a quartz cell having a 1 cm square light absorption part, and the value (λs) measured for absorbance at a wavelength of 336 nm using a commercially available ultraviolet spectrophotometer, and the value obtained by measuring the absorbance of toluene alone as a reference using the same method. From (λo), the ultraviolet absorbance is obtained by λc = λs−λo. Examples of commercially available spectrophotometers include an ultraviolet-visible spectrophotometer (UV-3100PC) manufactured by Shimadzu Corporation.

  As yellow pigments, compounds typified by condensed azo compounds, isoindolinone compounds and the like are used. Specifically, C.I. I. CI Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 150, 155, 168, 180, 194, etc. are preferably used. It is done.

  As the magenta pigment, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds are used. Specifically, C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 122, 144, 146, 166, 169, 17.3, 184, 185, 202, 206, 207, 209, 220, 221, 238, 254, C.I. I. Pigment Violet 19 or the like is preferably used. Among them, C.I. I. Pigment red 122, 202, 207, 209, C.I. I. A quinacridone pigment represented by pigment violet 19 is particularly preferred. Among the quinacridone pigments, C.I. I. A compound represented by CI Pigment Red 122 is particularly preferable.

  As the cyan pigment, copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds, and the like can be used. Specifically, C.I. I. Pigment blue 1, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, 66 and the like; I. Pigment Green 7, 36, etc. can be used particularly preferably.

  The toner used in the image forming apparatus of the present invention preferably contains a wax for imparting releasability. Any wax can be used as long as it has releasability, and is not particularly limited. Specifically, olefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene, and copolymer polyethylene; paraffin wax; ester waxes having a long-chain aliphatic group such as behenyl behenate, montanate ester, stearyl stearate; water Plant waxes such as soy castor oil and carnauba wax; ketones having long chain alkyl groups such as distearyl ketone; silicones having alkyl groups; higher fatty acids such as stearic acid; long chain aliphatic alcohols such as eicosanol; glycerin and pentaerythritol Examples include carboxylic acid esters or partial esters of polyhydric alcohols obtained from polyhydric alcohols such as polyhydric alcohols and long chain fatty acids; higher fatty acid amides such as oleic acid amides and stearic acid amides; low molecular weight polyesters and the like.

  In order to improve the fixability among these waxes, the melting point of the wax is preferably 30 ° C. or higher, more preferably 40 ° C. or higher, and particularly preferably 50 ° C. or higher. Moreover, 100 degrees C or less is preferable, 90 degrees C or less is still more preferable, and 80 degrees C or less is especially preferable. If the melting point is too low, the wax tends to be exposed and sticky after fixing, and if the melting point is too high, the fixability at low temperatures is poor. Furthermore, as the wax compound species, ester waxes obtained from aliphatic carboxylic acids and mono- or polyhydric alcohols are preferred, and ester waxes having 20 to 100 carbon atoms are preferred.

  The above waxes may be used alone or in combination. Further, the melting point of the wax compound can be appropriately selected depending on the fixing temperature for fixing the toner. The amount of the wax used is preferably 4 to 20 parts by weight, particularly preferably 6 to 18 parts by weight, and more preferably 8 to 15 parts by weight with respect to 100 parts by weight of the toner. In addition, when the volume median diameter (Dv50) of the toner is 7 μm or less, that is, when the toner has a small particle diameter, the exposure of the wax to the toner surface becomes extremely intense as the amount of the wax used increases. The storage stability of the toner is deteriorated. The toner of the present invention has a small particle size with a sharp particle size distribution that does not cause deterioration of the toner characteristics as compared with conventional toners even when the amount of wax used is large as in the above range. It is.

  The toner used in the image forming apparatus of the present invention may be one in which a known external additive is blended on the surface of the toner base particles in order to control fluidity and developability. External additives include metal oxides and hydroxides such as alumina, silica, titania, zinc oxide, zirconium oxide, cerium oxide, talc and hydrotalcite, titanium such as calcium titanate, strontium titanate and barium titanate. Examples thereof include acid metal salts, nitrides such as titanium nitride and silicon nitride, carbides such as titanium carbide and silicon carbide, and organic particles such as acrylic resins and melamine resins. Among these, silica, titania, and alumina are preferable, and those that have been surface-treated with, for example, a silane coupling agent or silicone oil are more preferable. The average primary particle diameter is preferably in the range of 1 to 500 nm, more preferably in the range of 5 to 100 nm. It is also preferable to use a combination of a small particle size and a large particle size in the particle size range. The total amount of the external additive is preferably in the range of 0.05 to 10 parts by weight, more preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the toner base particles.

<Toner production method>
The method for producing the toner used in the image forming apparatus of the present invention is not particularly limited. That is, the toner can be produced by a pulverization method or a method of forming particles in an aqueous medium. When a toner is manufactured by a pulverization method, fine particles are generally easily generated, so that a classification step is necessary. In particular, an excessive classification operation may be required in order to satisfy the toner particle size requirement in the present invention, and the yield is remarkably reduced. Such an operation is not preferable from an industrial point of view. The pulverized toner is not excluded as the toner used in the image forming apparatus. On the other hand, it is preferable that the toner of the present invention forms particles in an aqueous medium from the viewpoint that it is difficult to generate fine powder and a classification step is not essential.

  As a production method for obtaining toner particles in an aqueous medium, a method in which radical polymerization is carried out in an aqueous medium such as a suspension polymerization method or an emulsion polymerization aggregation method (hereinafter abbreviated as “polymerization method”), the obtained toner is referred to as “ (Abbreviated as “polymerized toner”), a chemical pulverization method represented by a melt suspension method, and the like can be preferably used. There is no particular limitation on the method for making the toner have a particle size in the specific range of the present invention. For example, in the production process of the polymerized toner, in the case of the suspension polymerization method, a method in which a high shearing force is applied in the process in which polymerizable monomer droplets are generated, or a dispersion stabilizer or the like is increased.

  As a method for obtaining a toner having a particle size in the specific range of the present invention, any of a polymerization method such as a pulverization method, a suspension polymerization method, an emulsion polymerization aggregation method, a chemical pulverization method represented by a melt suspension method, etc. Production methods can also be used, but in the “pulverization method”, “suspension polymerization method”, and “chemical pulverization method represented by the melt suspension method”, all of them are larger than the particle diameter of the toner. In order to adjust to a small size, if it is attempted to reduce the average particle size, the particle size ratio on the small particle side tends to increase, and an excessive burden is imposed in the classification step and the like. In contrast, the emulsion polymerization agglomeration method has a relatively sharp particle size distribution and is adjusted from a size smaller than the particle size of the toner to a larger size. A toner having a distribution is obtained. Therefore, for the above reasons, it is particularly preferable to produce the toner used in the image forming apparatus of the present invention by the emulsion polymerization aggregation method.

  The following is a method for producing particles by polymerization in an aqueous medium, and further a method for producing particles by an emulsion polymerization agglomeration method from the viewpoint that fine particles are not easily generated among the methods for forming particles in an aqueous medium. explain.

  When a toner is produced by an emulsion polymerization aggregation method, it usually has a polymerization process, a mixing process, an aggregation process, an aging process, and a washing / drying process. That is, generally, a dispersion liquid containing primary polymer particles obtained by emulsion polymerization is mixed with a dispersion liquid such as a colorant, a charge control agent, and wax, and the primary particles in the dispersion liquid are aggregated to form core particles. Then, if necessary, the toner base particles can be obtained by washing and drying the particles obtained by fusing and adhering the resin fine particles or the like as necessary.

  In order to obtain a toner satisfying the above formula (3), it is preferable to employ an operation in which the aggregation speed is not high compared to the operation normally performed in the aggregation step. Examples of operations that do not cause the aggregation speed to be high include, for example, cooling the dispersion to be used in advance, adding the dispersion over time, adopting an electrolyte that does not have a large aggregating action, continuously using the electrolyte, or There are methods such as intermittent addition, slowing the rate of temperature rise, and long aggregation time. In the aging step, it is preferable to adopt an operation in which the aggregated particles are difficult to redisperse. Examples of the operation in which the agglomerated particles are difficult to finely disperse include, for example, a method in which the number of revolutions for stirring is decreased, a dispersion stabilizer is added continuously or intermittently, and a dispersion stabilizer and water are mixed in advance. The toner satisfying the above formula (3) is a step of removing a part of particles having a volume median diameter (Dv50) or less from the finally obtained toner or toner base particles by an operation such as classification. It is preferable to obtain without going through.

  As the binder resin constituting the polymer primary particles used in the emulsion polymerization aggregation method, one or more polymerizable monomers that can be polymerized by the emulsion polymerization method may be appropriately used. Examples of the polymerizable monomer include “a polymerizable monomer having an acidic group” (hereinafter sometimes simply referred to as “acidic monomer”), “a polymerizable monomer having a basic group” (hereinafter simply referred to as “basic monomer”). "Polymerizable monomer having a polar group" (hereinafter sometimes referred to simply as "polar monomer") and "polymerizability having neither an acidic group nor a basic group" It is preferable to use “monomer” (hereinafter sometimes referred to as “other monomer”) as a raw material polymerizable monomer. At this time, each polymerizable monomer may be added separately, or a plurality of polymerizable monomers may be mixed in advance and added simultaneously. Furthermore, it is also possible to change the polymerizable monomer composition during the addition of the polymerizable monomer. Further, the polymerizable monomer may be added as it is, or may be added as an emulsion prepared by mixing with water or an emulsifier in advance.

  Examples of the “acidic monomer” include polymerizable monomers having a carboxyl group such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid and cinnamic acid, polymerizable monomers having a sulfonic acid group such as sulfonated styrene, vinyl Examples thereof include polymerizable monomers having a sulfonamide group such as benzenesulfonamide. Examples of the “basic monomer” include aromatic vinyl compounds having an amino group such as aminostyrene, and nitrogen-containing heterocyclic ring-containing polymerizable monomers such as vinylpyridine and vinylpyrrolidone.

  These polar monomers may be used alone or in combination, and may exist as a salt with a counter ion. Among these, it is preferable to use an acidic monomer, and (meth) acrylic acid is more preferable. The proportion of the total amount of polar monomers in 100% by mass of all polymerizable monomers constituting the binder resin as the polymer primary particles is preferably 0.05% by mass or more, more preferably 0.3% by mass or more, and particularly Preferably it is 0.5 mass% or more, More preferably, it is 1 mass% or more. The upper limit is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 2% by mass or less. When it is in the above range, the dispersion stability of the obtained polymer primary particles is improved, and the particle shape and particle diameter can be easily adjusted in the aggregation step.

  “Other monomers” include styrenes such as styrene, methylstyrene, chlorostyrene, dichlorostyrene, p-tert-butylstyrene, pn-butylstyrene, pn-nonylstyrene, methyl acrylate, acrylic acid Acrylic esters such as ethyl, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hydroxyethyl acrylate, ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, methacryl Methacrylates such as isobutyl acid, hydroxyethyl methacrylate, ethylhexyl methacrylate, acrylamide, N-propylacrylamide, N, N-dimethylacrylamide, N, N-dipropylacrylamide, N N- dibutyl acrylamide, acrylic acid amide and the like. A polymerizable monomer may be used independently and may be used in combination of multiple.

  In the present invention, among the above-mentioned polymerizable monomers used in combination, as a preferred embodiment, an acidic monomer and other monomers may be used in combination. More preferably, (meth) acrylic acid is used as the acidic monomer, and a polymerizable monomer selected from styrenes and (meth) acrylic acid esters is used as the other monomer. It is preferable to use (meth) acrylic acid as the monomer, and use a combination of styrene and (meth) acrylic acid esters as the other monomer, and particularly preferably use (meth) acrylic acid as the acidic monomer and other monomers. As a combination of styrene and n-butyl acrylate.

  Furthermore, it is also preferable to use a crosslinked resin as the binder resin constituting the polymer primary particles. In that case, a polyfunctional monomer having radical polymerizability is used as a crosslinking agent shared with the above polymerizable monomer. Examples of the multifunctional monomer include divinylbenzene, hexanediol diacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol acrylate, diallyl phthalate, and the like. Is mentioned. In addition, a polymerizable monomer having a reactive group in a pendant group such as glycidyl methacrylate, methylol acrylamide, acrolein or the like can be used as a crosslinking agent. Among them, radically polymerizable bifunctional monomers are preferable, and divinylbenzene and hexanediol diacrylate are particularly preferable.

  These crosslinking agents such as polyfunctional monomers may be used alone or in combination. When a crosslinked resin is used as the binder resin constituting the polymer primary particles, the blending ratio of the crosslinking agent such as a polyfunctional monomer in the total polymerizable monomer constituting the resin is preferably 0.005% by mass or more, More preferably, it is 0.1 mass% or more, More preferably, it is 0.3 mass% or more, Preferably it is 5 mass% or less, More preferably, it is 3 mass% or less, More preferably, it is 1 mass% or less. desirable.

  Known emulsifiers can be used for the emulsion polymerization, but one or more emulsifiers selected from cationic surfactants, anionic surfactants and nonionic surfactants are used in combination. be able to.

  Examples of the cationic surfactant include dodecyl ammonium chloride, dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, hexadecyl trimethyl ammonium bromide and the like.

  Examples of the anionic surfactant include fatty acid soaps such as sodium stearate and sodium dodecanoate, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and sodium lauryl sulfate.

  Nonionic surfactants include, for example, polyoxyethylene dodecyl ether, polyoxyethylene hexadecyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene sorbitan monooleate ether, monodecanoyl sucrose, etc. Is mentioned.

  The amount of the emulsifier is usually 1 to 10 parts by weight with respect to 100 parts by weight of the polymerizable monomer, and these emulsifiers include, for example, partially or completely saponified polyvinyl alcohol such as saponified polyvinyl alcohol, hydroxy One type or two or more types of cellulose derivatives such as ethyl cellulose can be used in combination as a protective colloid.

  Examples of the polymerization initiator include hydrogen peroxide; persulfates such as potassium persulfate; organic peroxides such as benzoyl peroxide and lauroyl peroxide; 2,2′-azobisisobutyronitrile; Azo compounds such as 2′-azobis (2,4-dimethylvaleronitrile); redox initiators and the like are used. One or more of them are usually used in an amount of about 0.1 to 3 parts by weight with respect to 100 parts by weight of the polymerizable monomer. Among them, it is preferable that at least part or all of the initiator is hydrogen peroxide or organic peroxides.

  Any of the polymerization initiators may be added to the polymerization system before, simultaneously with, or after the addition of the polymerizable monomer, and these addition methods may be combined as necessary.

  In the emulsion polymerization, a known chain transfer agent can be used as necessary. Specific examples of such a chain transfer agent include t-dodecyl mercaptan, 2-mercaptoethanol, diisopropylxanthogen, four Examples thereof include carbon chloride and trichlorobromomethane. The chain transfer agent may be used alone or in combination of two or more, and is usually used in a range of 5% by mass or less based on the total polymerizable monomer. Moreover, a pH adjuster, a polymerization degree adjuster, an antifoaming agent, etc. can be further mix | blended with a reaction system suitably.

  In the emulsion polymerization, the polymerizable monomer is polymerized in the presence of a polymerization initiator, and the polymerization temperature is usually 50 to 120 ° C, preferably 60 to 100 ° C, and more preferably 70 to 90 ° C.

  The volume average diameter (Mv) of the polymer primary particles obtained by emulsion polymerization is usually 0.02 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm or more, and usually 3 μm or less, preferably 2 μm or less. More preferably, the thickness is 1 μm or less. When the particle size is less than the above range, it may be difficult to control the aggregation rate. When the particle size exceeds the above range, the particle size of the toner obtained by aggregation tends to be large, and a toner having a target particle size can be obtained. It can be difficult.

  Tg by the DSC method of the binder resin as the polymer primary particles in the present invention is preferably 40 to 80 ° C, more preferably 55 to 65 ° C. Within this range, the storage stability is good and, in addition, the cohesiveness is not impaired. When Tg is too high, the cohesiveness is poor, and an aggregating agent must be added excessively or the aggregation temperature must be excessively increased. As a result, fine powder may be easily generated. Here, when the Tg of the binder resin overlaps with the caloric change based on other components, for example, the melting peak of polylactone or wax, it is not possible to make a clear judgment, and the toner was prepared in a state in which such other components were excluded. The Tg at the time is meant.

  In the present invention, the acid value of the binder resin constituting the polymer primary particles is not particularly limited, but is preferably 3 to 50 mgKOH / g, more preferably 5 to 30 mgKOH / g, as a value measured by the method of JISK-0070. It is.

  The lower limit of the solid content concentration of the polymer primary particles in the “polymer primary particle dispersion” used in the present invention is preferably 14% by mass or more, and more preferably 21% by mass or more. On the other hand, the upper limit is preferably 30% by mass or less, and more preferably 25% by mass or less. When it is within the above range, it is easy to adjust the aggregation speed of the polymer primary particles empirically in the aggregation process, and as a result, the particle diameter, particle shape, and particle size distribution of the core particles can be easily adjusted to an arbitrary range. It becomes.

  In the present invention, a dispersion liquid containing polymer primary particles obtained by emulsion polymerization is mixed with a dispersion liquid such as a colorant, a charge control agent, and wax, and the primary particles in the dispersion liquid are aggregated to form core particles. The toner base particles are preferably obtained by washing and drying the particles obtained by fusing after the shell coating step for fixing or adhering resin fine particles.

  The ratio of the resin fine particles to the whole core particles is preferably 0.5 to 30 parts by weight, particularly preferably 5 to 20 parts by weight with respect to 100 parts by weight of the core particles.

  The resin fine particles may be produced by the same method as the above polymer primary particles, and the structure thereof is not particularly limited, but the polar monomer occupying in 100% by mass of all polymerizable monomers constituting the binder resin as the resin fine particles The ratio of the total amount is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and further preferably 0.2% by mass or more. The upper limit is preferably 3% by mass or less, more preferably 1.5% by mass or less. When it is within the above range, the dispersion stability of the obtained resin fine particles is improved, and the particle shape and particle diameter can be easily adjusted in the aggregation step.

  Further, the proportion of the total amount of polar monomers in 100% by mass of the total polymerizable monomer constituting the binder resin as the resin fine particles is in 100% by mass of the total polymerizable monomer constituting the binder resin as the polymer primary particle. It is preferable that the ratio is smaller than the ratio of the total amount of polar monomers occupied because it is easy to adjust the particle shape and particle diameter in the aggregation process, the generation of fine powder can be suppressed, and the charging characteristics are excellent.

  In addition, the Tg of the binder resin as the resin fine particles is preferably higher than the Tg of the binder resin as the polymer primary particles from the viewpoint of storage stability and the like.

  The colorant is not particularly limited as long as it is a commonly used colorant. Examples thereof include the pigments described above, carbon black such as furnace black and lamp black, and magnetic colorants. The content of the colorant may be an amount sufficient for the obtained toner to form a visible image by development. For example, the content is preferably in the range of 1 to 25 parts by weight in the toner, more preferably 1 to 15 parts by weight, particularly preferably 3 to 12 parts by weight.

The colorant may have magnetism, and examples of the magnetic colorant include a ferromagnetic material that exhibits ferrimagnetism or ferromagnetism in the vicinity of 0 to 60 ° C., which is a use environment temperature of a printer, a copying machine, and the like. Is, for example, magnetite (Fe ₃ O ₄ ), maghemite (γ-Fe ₂ O ₃ ), an intermediate or mixture of magnetite and maghemite, M _x Fe _3-x O ₄ , where M is Mg, Spinel ferrite such as Mn, Fe, Co, Ni, Cu, Zn, Cd, hexagonal ferrite such as BaO.6Fe ₂ O ₃ , SrO.6Fe ₂ O ₃ , Y ₃ Fe ₅ O ₁₂ , Sm ₃ Fe ₅ O garnet-type oxides such as _12, shown rutile oxides such as CrO _2, and, Cr, Mn, Fe, Co, the magnetic near 0 to 60 ° C. of such metal or their ferromagnetic alloys such as Ni Ones, and among them, magnetite, maghemite, or magnetite and maghemite intermediates are preferred.

  When it is contained from the viewpoint of scattering prevention, charge control, etc. while having characteristics as a non-magnetic toner, the content of the magnetic powder in the toner is 0.2 to 10% by mass, preferably 0.5 to 0.5%. It is 8 mass%, More preferably, it is 1-5 mass%. When used as a magnetic toner, the content of the magnetic powder in the toner is usually 15% by mass or more, preferably 20% by mass or more, and usually 70% by mass or less, preferably 60% by mass or less. It is desirable. If the content of the magnetic powder is less than the above range, the magnetic force required for the magnetic toner may not be obtained, and if it exceeds the above range, it may cause poor fixing properties.

  As a blending method of the colorant in the emulsion polymerization aggregation method, usually, a polymer primary particle dispersion and a colorant dispersion are mixed to form a mixed dispersion, and then aggregated to obtain a particle aggregate. The colorant is preferably used in the state of being emulsified in water by a mechanical means such as a sand mill or a bead mill in the presence of an emulsifier. At this time, the colorant dispersion is preferably added with 10 to 30 parts by weight of the colorant and 1 to 15 parts by weight of the emulsifier with respect to 100 parts by weight of water. The particle diameter of the colorant in the dispersion is monitored while being dispersed, and the volume average diameter (Mv) is finally adjusted to 0.01 to 3 μm, more preferably 0.05 to It is preferable to control within the range of 0.5 μm. The blend of the colorant dispersion at the time of emulsion aggregation is calculated and used so as to be 2 to 10% by mass in the finished toner base particles after aggregation.

  The wax may be contained in the polymer primary particles or in the resin fine particles. However, usually, with the increase in the amount of wax used, the aggregation control tends to deteriorate and the particle size distribution tends to be broad.

  Therefore, as a method of blending the wax in the emulsion polymerization aggregation method, a wax dispersion that has been previously emulsified and dispersed in water at a volume average diameter (Mv) of 0.01 to 2.0 μm, more preferably 0.01 to 0.5 μm, is emulsified. It is preferable to add at the time of superposition | polymerization or to add at the aggregation process. In order to disperse the wax with a suitable dispersed particle diameter in the toner, it is preferable to add the wax as a seed during emulsion polymerization. By adding as a seed, polymer primary particles in which wax is encapsulated can be obtained, so that a large amount of wax does not exist on the toner surface, and deterioration of chargeability and heat resistance of the toner can be suppressed. The wax content in the polymer primary particles is preferably 4 to 30% by mass, more preferably 5 to 20% by mass, and particularly preferably 7 to 15% by mass.

  Also, wax may be contained in the resin fine particles, and in this case as well, it is preferable to add wax as a seed during emulsion polymerization, as in the case of obtaining polymer primary particles. The content ratio of the wax in the entire resin fine particles is preferably smaller than the content ratio of the wax in the entire polymer primary particles. Generally, when wax is contained in resin fine particles, the fixability is improved, but on the other hand, the generation amount of fine powder tends to increase. The reason for this is that the fixability is improved because the speed of movement of the wax to the toner surface is increased when heat is applied, but the inclusion of the wax in the resin fine particles broadens the particle size distribution of the resin fine particles. It is considered that the aggregation control becomes difficult, and as a result, an increase in fine powder is caused.

  In the toner used in the image forming apparatus of the present invention, a charge control agent may be blended in order to impart charge amount and charge stability. Conventionally known compounds are used as the charge control agent. Examples thereof include hydroxycarboxylic acid metal complexes, azo compound metal complexes, naphthol compounds, naphthol compound metal compounds, nigrosine dyes, quaternary ammonium salts, and mixtures thereof. The blending amount of the charge control agent is preferably in the range of 0.1 to 5 parts by weight with respect to 100 parts by weight of the resin.

  When a charge control agent is contained in the toner in the emulsion polymerization aggregation method, the charge control agent is blended with a polymerizable monomer or the like at the time of emulsion polymerization, or is blended in the aggregation process with the polymer primary particles and the colorant. The blended primary particles, the colorant, and the like can be blended by a method such as blending after agglomeration to obtain an appropriate particle size as a toner. Of these, the charge control agent is preferably emulsified and dispersed in water using an emulsifier, and used as an emulsified dispersion having a volume average diameter (Mv) of 0.01 μm to 3 μm. The blend of the charge control agent dispersion at the time of emulsion aggregation is calculated and used so as to be 0.1 to 5% by mass in the finished toner base particles after aggregation.

  The volume average diameter (Mv) of polymer primary particles, resin fine particles, colorant particles, wax particles, charge control agent particles, etc. in the above dispersion is measured using a nanotrack by the method described in the examples. , Defined as its measured value.

  In the aggregation step in the emulsion polymerization aggregation method, the above-described primary polymer particles, resin fine particles, colorant particles, and charge components such as a charge control agent and wax are mixed at the same time or sequentially. It is possible to prepare a dispersion of the above components, that is, a polymer primary particle dispersion, a resin fine particle dispersion, a colorant particle dispersion, a charge control agent dispersion, and a wax fine particle dispersion. It is preferable from the viewpoint of uniformity.

  In addition, when mixing these different types of dispersions, the components contained in each dispersion have different agglomeration speeds. Therefore, in order to perform agglomeration uniformly, it is added over a certain period of time continuously or intermittently. It is preferable to mix them. Since the suitable time required for the addition varies depending on the amount of the dispersion to be mixed, the solid concentration, and the like, it is preferable to adjust appropriately. For example, when the colorant particle dispersion is mixed with the polymer primary particle dispersion, it is preferably added over 3 minutes or more. Also, when mixing the resin fine particle dispersion with the core particles, it is preferable to add over 3 minutes.

  The agglomeration treatment includes a heating method, a method of adding an electrolyte, a method of reducing the concentration of an emulsifier in the system, a method of combining these, and the like. When primary particles are agglomerated under stirring to obtain particle agglomerates that are approximately the size of the toner, the particle size of the particle agglomerates is controlled from the balance between the agglomeration force between the particles and the shearing force due to agitation. However, the cohesive force can be increased by the above method.

As an electrolyte in the case of performing aggregation by adding an electrolyte, either an organic salt or an inorganic salt may be used. Specifically, NaCl, KCl, LiCl, Na ₂ SO ₄ , K ₂ SO ₄ , Li ₂ SO ₄ may be used. Inorganic salts having a monovalent metal cation such as CH ₃ COONa, C ₆ H ₅ SO ₃ Na; inorganic salts having a divalent metal cation such as MgCl ₂ , CaCl ₂ , MgSO ₄ , CaSO ₄ , ZnSO ₄ ; Examples thereof include inorganic salts having a trivalent metal cation such as Al ₂ (SO ₄ ) ₃ and Fe ₂ (SO ₄ ) ₃ . Among these, when an inorganic salt having a divalent or higher polyvalent metal cation is used, it is preferable in terms of productivity because the agglomeration speed is increased. On the other hand, the amount of polymer primary particles and the like that are not incorporated into the core particle is small. As a result, fine powder that does not reach the desired toner particle size is likely to be generated. Therefore, it is preferable to use an inorganic salt having a monovalent metal cation that does not have a strong aggregating action in terms of suppressing the amount of fine powder generated.

  The amount of the electrolyte used varies depending on the type of electrolyte, target particle size, etc., but is usually 0.05 to 25 parts by weight, preferably 0.1 to 15 parts per 100 parts by weight of the solid component of the mixed dispersion. Part by weight, more preferably 0.1 to 10 parts by weight. When the amount used is less than the above range, the progress of the agglutination reaction is slow, and fine particles of 1 μm or less remain after the agglomeration reaction, or the average particle size of the obtained particle aggregate does not reach the target particle size. In the case of exceeding the above range, it tends to be agglomerated rapidly, making it difficult to control the particle size, and the obtained core particles may cause problems such as inclusion of coarse powder or irregular shapes. is there.

  In addition, it is preferable that the electrolyte is added not intermittently but intermittently or continuously over a certain period of time. The addition time varies depending on the amount used, but is preferably added over 0.5 minutes. Usually, when an electrolyte is added, abrupt aggregation starts as soon as the electrolyte is added, so that there is a tendency that a large amount of polymer primary particles, colorant particles, aggregates, and the like left behind in the aggregation remain. These are considered to be one of the sources of fine powder. According to the above operation, uniform agglomeration can be performed without abrupt agglomeration, so that generation of fine powder can be prevented.

  Moreover, 20-70 degreeC is preferable and, as for the final temperature of the aggregation process in the case of performing aggregation by adding electrolyte, 30-60 degreeC is more preferable. Here, controlling the temperature before the aggregation step is one of the methods for controlling the toner base particles to a specific range of particle sizes. Some colorants added to the aggregating step induce aggregation, such as the above-described electrolyte, and sometimes agglomerate without adding an electrolyte. Therefore, the aggregation can be prevented by cooling the temperature of the polymer primary particle dispersion in advance when mixing the colorant dispersion. This aggregation causes fine powder to be generated. In the present invention, the polymer primary particles are preferably cooled in advance in a range of preferably 0 to 15 ° C, more preferably 0 to 12 ° C, and still more preferably 2 to 10 ° C. Note that this method is not effective only when the electrolyte is added to perform aggregation, and the aggregation is performed without adding an electrolyte, such as a method of controlling the pH or adding a polar organic solvent such as alcohol to perform the aggregation method. The method is also used, and is not particularly limited to the aggregation method.

  The final temperature of the agglomeration step in the case of agglomeration by heating is usually a temperature range of (Tg-20 ° C) to Tg of the polymer primary particles, and a range of (Tg-10 ° C) to (Tg-5 ° C). It is preferable that

  In addition, as a method for preventing sudden agglomeration in order to prevent generation of fine powder, there is a method of adding demineralized water or the like. The method of adding demineralized water or the like is not a method that is actively employed in terms of production efficiency because the coagulation action is not so strong compared to the method of adding electrolyte, but rather a large amount of filtrate is obtained in the subsequent filtration step, etc. May be undesirable. However, it is very effective when fine aggregation control is required as in the toner used in the image forming apparatus of the present invention. Moreover, in this invention, it is preferable to employ | adopt in combination with the method of adding the said heating method, the method of adding electrolyte, etc. At this time, the method of adding demineralized water after adding the electrolyte is particularly preferable in that the aggregation is easily controlled.

  The time required for agglomeration is optimized by the shape of the apparatus and the processing scale. In order to reach the target particle size of the toner base particles, the temperature at which the aggregation process is completed, for example, the emulsifier It is preferable that the time from the temperature 8 ° C. lower than the temperature at the time of operation to stop the growth of the core particles by addition, pH control, etc. (hereinafter referred to as the aggregation final temperature) to 30 minutes or more is 1 hour. More preferably, the above is used. The polymer core particles, colorant particles, or aggregates thereof remaining by extending the time are not left behind, but are taken into the target core particles or agglomerate with each other, so that the target core is obtained. Become a particle.

  In the present invention, toner mother particles can be formed by coating (adhering or fixing) resin fine particles on the surface of the core particles as necessary. The volume average diameter (Mv) of the resin fine particles is preferably 0.02 μm to 3 μm, more preferably 0.05 μm to 1.5 μm. Generally, the use of the resin fine particles promotes the generation of fine powder that does not reach a predetermined toner particle size. Therefore, the amount of fine powder less than the predetermined toner particle size is increased in the conventional toner coated with resin fine particles.

  In the present invention, when the amount of the wax is increased, the high temperature fixability is improved, but the wax is likely to be exposed on the toner surface, so that the chargeability and heat resistance may be deteriorated. The deterioration of performance can be prevented by coating with resin fine particles not containing.

  However, when the resin fine particles contain wax for the purpose of improving the high-temperature fixability, the resin fine particles once attached to the surface of the core particles are easily peeled off. This is because the particle size distribution of the resin fine particles described above becomes wide, and there are large particle size resin fine particles with weak adhesion. Therefore, in order to reduce the peeling off, it is preferable to raise the temperature while adding an aqueous solution in which a dispersion stabilizer and water are mixed in advance in a liquid in which particles having resin fine particles attached to the surface are dispersed. .

  When adopting the conventional method “step of starting the temperature rise after the addition of the emulsifier”, that is, when the aging step is performed after abruptly reducing the cohesive force, once the cohesive force is drastically reduced. The adhered resin fine particles may be easily detached. Therefore, it is preferable to fuse the resin fine particles after adhering them without significantly reducing the cohesive force and suppressing the particle diameter growth.

  In the emulsion polymerization aggregation method, in order to increase the stability of the particle aggregate obtained by aggregation, an emulsifier and a pH adjuster are added as a dispersion stabilizer to reduce the aggregation force between the particles, thereby growing the toner base particles. It is preferable to add an aging step for causing fusion between the agglomerated particles after stopping.

  The blending amount in the case of blending the emulsifier is not limited, but is preferably 0.1 parts by weight or more, more preferably 1 part by weight or more, further preferably 3 parts by weight or more with respect to 100 parts by weight of the solid component of the mixed dispersion. Moreover, it is preferably 20 parts by weight or less, more preferably 15 parts by weight or less, and still more preferably 10 parts by weight or less. After the aggregation process, before the completion of the ripening process, by adding an emulsifier or by increasing the pH value of the flocculation liquid, aggregation of the particle aggregates aggregated in the aggregation process can be suppressed. The generation of coarse particles in the toner can be suppressed.

  Here, in the small particle size toner used in the image forming apparatus of the present invention, as a method for controlling the particle size within a specific range which means that the particle size distribution is sharp, before the step of adding an emulsifier or a pH adjuster. There is a method of reducing the stirring rotation speed, that is, reducing the shearing force by stirring. This method is preferably employed when a system having a weak aggregating action, such as an emulsifier or a pH adjuster, is added at a time to rapidly shift to a stable (dispersed) system. As described above, if a method of raising the temperature while adding an aqueous solution in which a dispersion stabilizer and water are mixed in advance is adopted, the system is too inclined to agglomerate when the stirring rotation speed is lowered, so that the particle size May lead to enlargement.

As an example, the toner having a specific particle size distribution used in the image forming apparatus of the present invention can be obtained by the above-described method. More specifically, the content of fine particles can be adjusted by reducing the number of rotations. it can. For example, when the stirring rotation speed is decreased from 250 rpm to 150 rpm, a toner having a small particle size with a sharper particle size distribution than that of a known toner can be provided. Toner having a specific particle size distribution used in the image forming apparatus of the present invention can be obtained. Can be obtained. However, this value is naturally
(A) The diameter of the stirring vessel (as a so-called general cylindrical shape) and the maximum diameter of the stirring blade (and its relative ratio)
(B) Height of the stirring vessel (c) Peripheral speed at the tip of the stirring blade (d) Shape of the stirring blade (e) Vary depending on conditions such as the position of the blade in the stirring vessel. About special (c), 1.0-2.5 m / sec is preferable, 1.2-2.3 m / sec is more preferable, 1.5-2.2 m / sec is especially preferable. This is because, within the above range, a suitable shear rate that does not peel off and does not enlarge is given to the particles.

  The temperature of the aging step is preferably not less than Tg of the binder resin as the polymer primary particles, more preferably not less than 5 ° C higher than the Tg, and preferably not more than 80 ° C higher than the Tg, more preferably The temperature is 50 ° C. or higher than the Tg. The time required for the aging step varies depending on the shape of the target toner, but after reaching the glass transition temperature of the polymer constituting the polymer primary particles, usually 0.1 to 5 hours, preferably 1 to It is desirable to hold for 3 hours.

  By such a heat treatment, the polymer primary particles in the aggregate are fused and integrated, and the shape of the toner base particles as the aggregate becomes close to a spherical shape. The particle aggregate before the aging step is considered to be an aggregate due to electrostatic or physical aggregation of the polymer primary particles, but after the aging step, the polymer primary particles constituting the particle aggregate are fused to each other. In addition, the shape of the toner base particles can be made nearly spherical. According to such an aging process, by controlling the temperature and time of the aging process, the shape of the polymer primary particles is agglomerated, a potato type with advanced fusion, a spherical form with further fusion For example, various shapes of toner can be manufactured according to the purpose.

  The particle aggregate obtained through each of the above steps is subjected to solid / liquid separation according to a known method, the particle aggregate is recovered, then washed as necessary, and then dried. Toner mother particles can be obtained.

  Further, resin fine particles mainly composed of a polymer are further formed on the surface of the particles obtained by the emulsion polymerization aggregation method by a method such as a spray drying method, an in-situ method, or a submerged particle coating method. As an outer layer, toner mother particles can be obtained by forming the toner with a thickness of preferably 0.01 to 0.5 μm (shell coating step).

  Further, in the emulsion polymerization aggregation method toner, the average circularity measured using a flow type particle image analyzer FPIA-2100 is preferably 0.90 or more, more preferably 0.92 or more, and further preferably 0.94 or more. It is. It is considered that the closer to a sphere, the less the charge amount is localized in the particles, and the developability tends to be uniform. However, making a perfect spherical toner deteriorates the cleaning property, so the average circularity Is preferably 0.98 or less, more preferably 0.97 or less.

  Further, at least one of the peak molecular weights in the gel permeation chromatography (hereinafter sometimes abbreviated as “GPC”) of the tetrahydrofuran (THF) soluble part of the toner is preferably 30,000 or more, more preferably 40,000 or more. More preferably, it is 50,000 or more, preferably 200,000 or less, more preferably 150,000 or less, and still more preferably 100,000 or less. When the peak molecular weight is lower than the above range, the mechanical durability in the non-magnetic one-component development method may be deteriorated. When the peak molecular weight is higher than the above range, the low temperature fixability and the fixing strength are deteriorated. There is a case.

  The chargeability of the emulsion polymerization aggregation method toner may be positively charged or negatively charged, but is preferably used as a negatively chargeable toner. Control of the chargeability of the toner can be adjusted by selection and content of the charge control agent, selection and blending amount of the external additive, and the like.

  The image forming apparatus using the toner satisfying the above particle size distribution condition can reduce the consumption amount, obtain a high image quality, prevent a cleaning failure in the cleaning process using the cleaning blade, and apply it to the electrophotographic photosensitive member. Filming, adhesion and accumulation of toner components on the charging roller, charging brush, etc. are prevented, and image defects do not occur. In addition, since the particle size distribution is sharp, the distribution of the behavior of each particle in the development process and transfer process (due to electric force, physical adhesion, and interstitial force) is small, and a good image with little scattering can be provided. .

  When toner having such a particle size distribution is used, an image forming apparatus in which transfer residual toner is difficult to pass between the electrostatic charge image holding member and the cleaning blade in combination with the cleaning blade can be realized. When the cleaning blade is made of a material having a rubber hardness of 50 to 90, the effect of the toner having such a particle size distribution is exhibited.

  Further, the transfer efficiency is also increased for the same reason. Particles with a small charge amount do not cause smearing of the white background of the image or scatter and stain the inside of the apparatus, and particles with a large charge amount adhere to members such as a layer regulating blade or a roller without being developed. Does not cause image defects such as faintness.

  In order to obtain a toner satisfying the above formula (3), it is preferable to employ an operation in which the aggregation speed is not high compared to the operation normally performed in the aggregation step. Examples of operations that do not cause the aggregation speed to be high include, for example, cooling the dispersion to be used in advance, adding the dispersion over time, adopting an electrolyte that does not have a large aggregating action, continuously using the electrolyte, or There are methods such as intermittent addition, slowing the rate of temperature rise, and long aggregation time. In the aging step, it is preferable to adopt an operation in which the aggregated particles are difficult to redisperse. Examples of operations in which the aggregated particles are difficult to finely disperse include, for example, a method in which the number of revolutions for stirring is lowered, a dispersion stabilizer is added continuously or intermittently, and a dispersion stabilizer and water are mixed in advance. The toner satisfying the above formula (3) is a step of removing a part of particles having a volume median diameter (Dv50) or less from the finally obtained toner or toner base particles by an operation such as classification. It is preferable to obtain without going through.

  The toner used in the image forming apparatus of the present invention is for a magnetic two-component developer coexisting with a carrier for conveying the toner to the electrostatic image portion by magnetic force, or a magnetic one component containing magnetic powder in the toner. It may be used for either a developer or a non-magnetic one-component developer that does not use magnetic powder as a developer. However, in order to exhibit the effects of the present invention remarkably, a non-magnetic one-component development system is particularly used. It is preferably used as a developer.

  When used as the magnetic two-component developer, the carrier that is mixed with the toner to form the developer is a known magnetic substance such as an iron powder type, ferrite type, or magnetite type carrier, or a resin coating on the surface thereof. Or a magnetic resin carrier can be used. As the carrier coating resin, generally known styrene resins, acrylic resins, styrene acrylic copolymer resins, silicone resins, modified silicone resins, fluorine resins, and the like can be used, but are not limited thereto. It is not a thing. The average particle size of the carrier is not particularly limited, but preferably has an average particle size of 10 to 200 μm. These carriers are preferably used in an amount of 5 to 100 parts by weight based on 1 part by weight of the toner.

  The image forming apparatus according to the present invention forms an electrostatic latent image on the electrostatic charge image holding member 1, adheres and develops electrostatically charged toner particles to the electrostatic latent image pattern, and then in the transfer step, the electrostatic charge image Toner is transferred from the holding member 1 onto a transfer material such as paper or an intermediate transfer member. The untransferred toner remaining on the electrostatic charge image holding member 1 is then scraped and collected by the cleaning blade 8 in contact with it in a cleaning process. The electrostatic charge image holding member from which the transfer residual toner has been removed returns to the electrostatic latent image forming step.

  The formation of the electrostatic latent image will be described. First, in the charging step for charging the electrostatic charge image holding member 1, when an electrophotographic photosensitive member is used as the electrostatic charge image holding member 1, the surface of the photosensitive member is uniformly charged by discharge from a charging roller, charging brush, corona wire, or the like. Is granted. The amount of charge is generally in the range of about 300 V to 1 KV in terms of the absolute value of the surface potential of the photoreceptor. In the charging step, it is preferable to use a contact charging member such as a charging roller or a charging brush. The reason for this is that, compared to non-contact charging methods such as corona charging, the contact method is charged by the potential balance of the micro area based on Paschen's law, so it is less affected by afterimages and transfer potentials. This is because it is suitable for forming a high image quality with a diameter toner.

  Next, the electrostatic surface image pattern is formed by releasing the charge on the surface of the photoreceptor by exposure to reflected light from the original or laser light. As the electrostatic charge image holding member 1, an electrostatic latent image pattern may be formed by a technique other than charging and exposure to a photosensitive member.

  In the development process, the above-described two-component development method, non-magnetic one-component development method, magnetic one-component method and the like are generally used. The toner 6 charged by frictional charging or the like is brought into contact with or brought close to the electrostatic charge image holding member 1 to transfer the toner 6 to the electrostatic latent image pattern.

  Hereinafter, a general case of the non-magnetic one-component development method will be described. From the toner storage chamber 7, the toner 6 is supplied to the developing roller 2. As a supply method, the toner 6 is naturally attached by its own weight, the toner 6 is moved to the vicinity of the developing roller 2 by agitating the agitator 5 and the like, and the adhesion is promoted by a toner roller. In addition, there is a method of sliding and transferring to the developing roller 2, or a combination thereof. The toner 6 adhering to the developing roller 2 is adjusted to uniform adhesion by a toner layer thickness regulating member 3 such as a doctor blade, an elastic blade, or a trimmer roller.

  The toner 6 is charged by frictional charging by friction between the toner 6 and the developing roller 2, the doctor blade 3, the sponge roller 4, and the like, and between the developing roller 2 and the doctor blade 3, and between the developing roller 2 and the sponge roller 4. There is a method of applying a voltage to the toner 6 to promote charging of the toner 6.

  As the developing roller 2, a general conductive rubber roller, a metal cylinder, or the like is used. The surface of the developing roller 2 may be the same as the material, but may be subjected to chemical surface treatment such as coating with a resin or the like, blasting treatment, oxidation, etc. to perform stable charge control. The same applies to the material of the doctor blade 3, and there may be a case where a resin-based elastic member such as urethane rubber is used, or a case where a leaf spring member such as a stainless steel plate or a square bar member is pressed. Further, like the developing roller 2, surface treatment may be performed.

  The developing roller 2 with the toner uniformly attached is brought into contact with or in proximity to the electrostatic charge image holding member 1 to transfer the toner from the developing roller 2 to the electrostatic charge image holding member 1 to develop the electrostatic latent image pattern. A development bias voltage is generally applied between the electrostatic charge image holding member 1 and the developing roller 2 in order to promote transfer and to prevent toner adhesion to a portion that should be white. The development bias potential is generally set to an intermediate potential between the white background portion and the print portion of the latent image pattern. However, an alternating voltage is also applied to promote development, and the development roller 2 and the electrostatic charge image holding member 1 There is also a jumping method in which the toner is reciprocated between the two and finally the development is faithful to the electrostatic latent image pattern.

  The electrostatic charge image holding member 1 to which toner is adhered and held in the development process transfers most of the toner to a transfer material (not shown) such as paper or an intermediate transfer body in the transfer process. The transfer material comes into contact with the electrostatic charge image holding member 1, and the toner is transferred by applying voltage or charge from the back surface. As a method of applying a voltage from the back surface, there are a method of applying a voltage to a conductive transfer roller or the like, a method of installing a corona wire or the like on the back surface, and transferring toner with a discharge charge.

  Untransferred toner that has not been transferred to the transfer material is scraped and collected by the cleaning blade 8 in the cleaning process. The cleaning blade 8 is preferably made of a material having a rubber hardness of 50 to 90. More preferably, it is 60-80. When it is within this range, the following effects are easily exhibited and the effects of the present invention are easily achieved. Here, the rubber hardness measurement method is based on JIS k6301 (spring type A type), and the above-mentioned “rubber hardness” is defined as that measured.

  The material of the cleaning blade 8 is not particularly limited, but urethane rubber, silicone rubber and the like are preferable. One end of the cleaning blade 8 is fixed, and the ridge line of the other free end is pressed against the electrostatic charge image holding member 1. The transfer residual toner accumulates in this contact portion. When a large amount of transfer residual toner accumulates, the toner is moved and stored from the cleaning blade 8 to the recovery chamber. In order to move to the collection chamber, the toner previously scraped off is pushed out by the toner that is sequentially scraped and moves toward the fixed end of the cleaning blade 8. There are many cases. Further, the collected transfer residual toner may be returned to the toner storage chamber 7 in the development process and reused.

  In the cleaning process, the cleaning blade 8 vibrates slightly due to the stick-and-slip phenomenon described above. When a large amount of toner having a particle size of 2.00 μm or more and 3.56 μm or less is included, cleaning failure is likely to occur, and this should be reduced as much as possible.

  Further, when the relationship with the volume median diameter is examined in detail, it is considered that the following phenomenon occurs with the stick-and-slip phenomenon. Along with the minute vibration, the cleaning blade is lifted up in a state where toner is temporarily sandwiched between the contact portion between the electrostatic charge image holding member and the edge of the edge of the cleaning blade. A slight gap is generated between the charge image holding members. The size of the gap is related to the volume median diameter (Dv50) of the toner, and it seems that the larger the volume median diameter (Dv50), the wider the gap and the higher the probability of the gap.

  Therefore, a toner having a relatively large volume median diameter (Dv50) in a volume median diameter (Dv50) in the range of 4.0 μm to 7.0 μm has a ratio of a particle diameter of 2.00 μm to 3.56 μm. Need to be less. On the other hand, in the toner having a relatively small volume median diameter (Dv50) in the volume median diameter (Dv50) in the range of 4.0 μm to 7.0 μm, the ratio of the particle diameter of 2.00 μm to 3.56 μm is In a small amount, a relatively large range is allowed. As shown in the examples and comparative examples, the relationship appears as a relational expression such as the expression (3).

  In addition, since the cleaning failure when a coarse material adheres to the cleaning blade continues to occur at the same location, the linear image failure continues to occur at the same location. The cleaning failure that has been made is a cleaning failure that occurs temporarily and not a long linear image failure. For this reason as well, it is considered that such a cleaning defect is caused by a phenomenon of temporary pinching.

  With regard to the cleaning performance of the toner having a volume median diameter (Dv50) larger than 7 μm, which has been widely used in the past, it is not necessary to consider the ratio of the particle diameter of 2.00 μm to 3.56 μm. This is thought to be because the phenomenon in which the toner is temporarily caught due to the vibration speed and vibration width peculiar to the stick-and-slip phenomenon is difficult to occur with toners larger than 7 μm.

  In recent years, a toner having a small volume median diameter (Dv50) has been used, and even a recent polymerized toner or a pulverized toner whose surface has been smoothed by surface treatment or the like is more temporarily used. The phenomenon of pinching is becoming more likely to occur, and in such toners, the cleaning performance of this kind can be preferably improved for the first time by the image forming method of the present invention.

  In addition, if the image forming method of the present invention is used, not only the improvement of the above-mentioned type of cleaning failure is seen, but also the conventionally known “cleaning failure when accumulated and adhered to the cleaning blade” is also observed. Can improve.

  After the cleaning process, the electrostatic charge image holding member 1 from which the toner is removed returns to the electrostatic latent image forming process (developing process). When a photosensitive member is used as the electrostatic charge image holding member 1, the previous electrostatic latent image pattern may be erased by static elimination light before the charge is uniformly applied.

  By using the toner for such an electrophotographic apparatus, an electrophotographic apparatus having particularly excellent cleaning characteristics can be constructed.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the following examples, “parts” means “parts by weight”.

<Measurement method and definition of volume average diameter (Mv)>
The volume average diameter (Mv) of particles having a volume average diameter (Mv) of less than 1 μm is handled by using Nitraso Co., Ltd., model: Microtrac Nanotrac 150 (hereinafter abbreviated as “Nanotrack”). In accordance with the instructions, using the company's analysis software Microtrac Particle Analyzer Ver10.1.2.-019EE, using ion-exchanged water with an electric conductivity of 0.5 μS / cm as the dispersion medium, enter the following conditions or the following conditions respectively: And measured by the method described in the instruction manual.

For wax dispersion and polymer primary particle dispersion,
Solvent refractive index: 1.333
-Measurement time: 100 seconds-Number of measurements: 1 time-Particle refractive index: 1.59
-Permeability: Transmission-Shape: True spherical shape-Density: 1.04

For pigment premix liquid and colorant dispersion,
Solvent refractive index: 1.333
-Measurement time: 100 seconds-Number of measurements: 1 time-Particle refractive index: 1.59
・ Transparency: Absorption ・ Shape: Non-spherical shape ・ Density: 1.00

<Measurement method and definition of volume median diameter (Dv50)>
As a pre-measurement treatment of the toner finally obtained through the external addition process, it was performed as follows. In a cylindrical polyethylene (PE) beaker having an inner diameter of 47 mm and a height of 51 mm, 0.100 g of toner using a spatula, 20% by weight DBS aqueous solution using a dropper (Daiichi Kogyo Seiyaku Co., Ltd., Neogen S-20A) 0.15 g was added. At this time, toner and a 20% DBS aqueous solution were added only to the bottom of the beaker so that the toner would not scatter on the edge of the beaker. Next, the mixture was stirred for 3 minutes using a spatula until the toner and 20% DBS aqueous solution became a paste. At this time, the toner was prevented from being scattered on the edge of the beaker.

  Subsequently, 30 g of dispersion medium Isoton II was added, and the mixture was stirred for 2 minutes using a spatula to obtain a uniform solution as a whole. Next, a fluororesin-coated rotor having a length of 31 mm and a diameter of 6 mm was placed in a beaker and dispersed using a stirrer at 400 rpm for 20 minutes. At this time, using a spatula at a rate of once every 3 minutes, macroscopic particles visually observed at the gas-liquid interface and the edge of the beaker were dropped into the beaker so as to form a uniform dispersion. Subsequently, this was filtered through a mesh having an opening of 63 μm, and the obtained filtrate was designated as “toner dispersion”.

  Regarding the measurement of the particle diameter during the production process of the toner base particles, the filtrate obtained by filtering the agglomerated slurry with a 63 μm mesh was used as the “slurry liquid”.

  The volume median diameter (Dv50) of the particles is Bocman Coulter's Multisizer III (aperture diameter 100 μm) (hereinafter abbreviated as “Multisizer”), the dispersion medium is Isoton II, and the above-mentioned “ The “toner dispersion liquid” or “slurry liquid” was diluted to a dispersoid concentration of 0.03% by mass and measured with Multisizer III analysis software with a KD value of 118.5. The measurement particle diameter range is from 2.00 to 64.00 μm, and this range is discretized into 256 divisions so as to be equidistant on a logarithmic scale, and the volume calculated based on the statistical values on the basis of the volume is the volume. The median diameter (Dv50) was used.

<Measurement Method and Definition of Number% (Dns) of Toner with Particle Size of 2.00 μm to 3.56 μm>
As a pre-measurement process for the toner after the external addition step, the following procedure was performed. In a cylindrical polyethylene (PE) beaker having an inner diameter of 47 mm and a height of 51 mm, 0.100 g of toner using a spatula, 20% by weight DBS aqueous solution using a dropper (Daiichi Kogyo Seiyaku Co., Ltd., Neogen S-20A) 0.15 g was added. At this time, toner and a 20% DBS aqueous solution were added only to the bottom of the beaker so that the toner would not scatter on the edge of the beaker. Next, the mixture was stirred for 3 minutes using a spatula until the toner and 20% DBS aqueous solution became a paste. At this time, the toner was prevented from being scattered on the edge of the beaker.

  Subsequently, 30 g of dispersion medium Isoton II was added, and the mixture was stirred for 2 minutes using a spatula, and the whole was made into a uniform solution visually. Next, a fluororesin-coated rotor having a length of 31 mm and a diameter of 6 mm was placed in a beaker and dispersed using a stirrer at 400 rpm for 20 minutes. At this time, macroscopic particles visually observed at the gas-liquid interface and the edge of the beaker were dropped into the beaker at a rate of once every 3 minutes so as to form a uniform dispersion. Subsequently, this was filtered with a mesh having an opening of 63 μm, and the obtained filtrate was used as a toner dispersion.

  For the number% (Dns) of toner having a particle size of 2.00 μm or more and 3.56 μm or less, a multisizer (aperture diameter 100 μm) is used, and Isoton II manufactured by the same company is used as a dispersion medium. The “slurry liquid” was diluted to a dispersoid concentration of 0.03% by mass and measured with Multisizer III analysis software with a KD value of 118.5.

  The lower limit particle size of 2.00 μm is the detection limit of the measuring device multisizer, and the upper limit particle size of 3.56 μm is a prescribed channel value in the measuring device multisizer. In the present invention, an area having a particle size of 2.00 μm or more and 3.56 μm or less is recognized as a fine powder area.

  The measurement particle size range is from 2.00 to 64.00 μm, and this range is discretized into 256 divisions so as to be equidistant on a logarithmic scale, and based on the statistical value on the basis of the number, 2.00 To 3.56 μm, the ratio of the particle size component was calculated on the basis of the number and was defined as “Dns”.

<Measuring method and definition of average circularity>
The “average circularity” in the present invention is measured as follows and is defined as follows. That is, the toner base particles are dispersed in a dispersion medium (Isoton II, manufactured by Beckman Coulter, Inc.) so as to be in the range of 5720-7140 particles / μL, and a flow type particle image analyzer (Sysmex Corporation (formerly Toa Medical Electronics)). (Manufactured by FPIA 2100), measurement is performed under the following apparatus conditions, and the value is defined as “average circularity”. In the present invention, the same measurement is performed three times, and an arithmetic average value of three “average circularity” is adopted as the “average circularity”.
・ Mode: HPF
-HPF analysis amount: 0.35 μL
-HPF detection number: 2000-2500

The following is measured by the above device and automatically calculated and displayed in the above device, and “circularity” is defined by the following formula.
[Circularity] = [Perimeter of a circle with the same area as the projected particle area] / [Perimeter of projected particle image]
And 2000-2500 which is the number of HPF detection is measured, and the arithmetic average (arithmetic mean) of the circularity of each individual particle is displayed on the apparatus as “average circularity”.

<Measurement method and definition of number variation coefficient>
What is the number variation coefficient?
100 × [standard deviation of number-based particle distribution] / [number average particle diameter]
The value represented by The particle size distribution of the present invention was measured as follows.

  The particle number coefficient of variation was determined by using Beckman Coulter's Multisizer III (aperture diameter 100 μm) (hereinafter abbreviated as “Multisizer”). Or “slurry liquid” was diluted to a dispersoid concentration of 0.03% by mass and measured with Multisizer III analysis software (V3.51) and a KD value of 118.5. The measurement particle diameter range is from 2.00 μm to 64.00 μm, and this range is discretized into 256 divisions so as to be equally spaced on a logarithmic scale, and based on the statistical values based on the number basis, the number basis particle The standard deviation of the distribution and the number average particle diameter were calculated according to a conventional method, and the number variation coefficient was calculated by the above formula.

<Method of measuring electrical conductivity>
The electrical conductivity was measured using a conductivity meter (a personal SC meter model SC72 and a detector SC72SN-11 manufactured by Yokogawa Electric Corporation) according to an ordinary method according to the instruction manual.

<Measuring method of melting point peak temperature, melting peak half width, crystallization temperature, crystallization peak half width>
From the endothermic curve when the temperature is raised from 10 ° C. to 110 ° C. at a rate of 10 ° C./min using the method described in the company's instruction manual using Seiko Instruments Inc. model: SSC5200, the melting point peak temperature The half-width of the melting peak was measured, and then the crystallization temperature and the half-width of the crystallization peak were measured from the exothermic curve when the temperature was lowered from 110 ° C. to 10 ° C. at a rate of 10 ° C./min.

<Measurement method of solid content concentration>
Using a solid content concentration measuring instrument INFRARED MOISTURE DETERMINATION BALANCE model FD-100, manufactured by Kett Science Laboratory, weighed 1.00 g of a sample containing solid content on a balance, and the conditions of a heater temperature of 300 ° C. and a heating time of 90 minutes The solid content concentration was measured.

<Method of live-action evaluation>
The image forming apparatus used for the evaluation of the actual image is a non-magnetic one-component rubber development roller contact development system, uses an organic photoreceptor as an electrostatic charge image holding member, charges the photoreceptor with a charging roller, and electrostatic latent with laser light. A printer with a process speed of 120 mm / second, in which an image is formed and transferred from a photoconductor to a transfer material such as paper held on a semiconductive belt, and the residual toner on the photoconductor is cleaned with a urethane rubber cleaning blade Was used.

  This urethane rubber had a rubber hardness of 70. The guaranteed lifespan of this printer at a 5% printing rate was 8,000. The resolution on the electrostatic charge image holding member was 600 dpi.

  100 g of toner was loaded in the cartridge of the image forming apparatus, and running (printing) was performed using a chart of 5% printing rate.

  In the evaluation of actual images, an image quality evaluation pattern was printed in the initial stage immediately after loading, after printing 500 sheets, and after printing 1000 sheets. Continued running depending on the situation. During the image quality evaluation pattern, running was performed with a pattern having a printing rate of 5%. Initially, at 500 sheets and 1000 sheets, toner scattering around the developing roller and contamination of the charging roller were also observed and confirmed.

Example 1
<Preparation of wax / long-chain polymerizable monomer dispersion H1>
Paraffin wax (HNP-9 manufactured by Nippon Seiki Co., Ltd., surface tension 23.5 mN / m, thermal characteristics: melting point peak temperature 82 ° C., melting peak half width 8.2 ° C., crystallization temperature 66 ° C., crystallization peak half width 13 27 ° C. (540 g), 2.8 parts stearyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), 1.9 parts 20% DBS aqueous solution, 68.3 parts demineralized water to 90 ° C. and heated to a homomixer (special The mixture was stirred for 10 minutes using Mark II f model manufactured by Meika Kogyo Co.

  Next, this dispersion was heated to 90 ° C., and circulation emulsification was started under a pressure condition of 25 MPa using a homogenizer (manufactured by Gorin, 15-M-8PA type). Dispersion was carried out until (Mv) reached 250 nm to prepare a wax / long-chain polymerizable monomer dispersion H1 (emulsion solid content concentration = 30.2 mass%).

<Preparation of polymer primary particle dispersion H1>
In a reactor (inner volume 21 L, inner diameter 250 mm, height 420 mm) equipped with a stirrer (three blades), a heating / cooling device, and each raw material / auxiliary charging device, the above wax / long-chain polymerizable monomer dispersion 35.6 parts (712.12 g) of H1 and 259 parts of demineralized water were charged, and the temperature was raised to 90 ° C. under a nitrogen stream while stirring.

  Thereafter, the mixture of the following “polymerizable monomers and the like” and “emulsifier aqueous solution” was added to the solution over 5 hours while continuing to stir the liquid. The time at which this mixture was started to be dropped was designated as “polymerization start”, and the following “initiator aqueous solution” was added over 4.5 hours from 30 minutes after the start of polymerization. Further, after 5 hours from the start of polymerization, the following “additional start” The agent aqueous solution ”was added over 2 hours, and the internal temperature was maintained at 90 ° C. for 1 hour while continuing stirring.

[Polymerizable monomers, etc.]
Styrene 76.8 parts (1535.0 g)
Butyl acrylate 23.2 parts Acrylic acid 1.5 parts Hexanediol diacrylate 0.7 parts Trichlorobromomethane 1.0 part

[Emulsifier aqueous solution]
20% DBS aqueous solution 1.0 part demineralized water 67.1 parts

[Initiator aqueous solution]
8% by mass aqueous hydrogen peroxide solution 15.5 parts 8% by mass L (+)-ascorbic acid aqueous solution 15.5 parts

[Additional initiator aqueous solution]
8 mass% L (+)-ascorbic acid aqueous solution 14.2 parts

  After completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer primary particle dispersion H1. The volume average diameter (Mv) measured using Nanotrac was 265 nm, and the solid content concentration was 22.3 mass%.

<Preparation of silicone wax dispersion H2>
Alkyl-modified silicone wax (thermal characteristics: melting point peak temperature 77 ° C., heat of fusion 97 J / g, melting peak half width 10.9 ° C., crystallization temperature 61 ° C., crystallization peak half width 17.0 ° C.) 27 parts (540 g) Then, 1.9 parts of a 20% DBS aqueous solution and 71.1 parts of demineralized water were placed in a 3 L stainless steel container, heated to 90 ° C., and stirred for 10 minutes with a homomixer (Mark II f model manufactured by Tokushu Kika Kogyo Co., Ltd.). Next, this dispersion was heated to 99 ° C., and circulation emulsification was started under a pressure of 45 MPa using a homogenizer (manufactured by Gorin Co., Ltd., 15-M-8PA type). ) To 240 nm to prepare a silicone wax dispersion H2 (emulsion solid content concentration = 27.3%).

<Preparation of polymer primary particle dispersion H2>
23.3 parts (466 g) of silicone wax dispersion H2 was added to a reactor (inner volume 21 L, inner diameter 250 mm, height 420 mm) equipped with a stirrer (three blades), a heating / cooling device, and each raw material / auxiliary charging device. ), 1.0 part of 20% DBS aqueous solution and 324 parts of demineralized water were added, the temperature was raised to 90 ° C. under a nitrogen stream, and 3.2 parts of 8% aqueous hydrogen peroxide solution, 8% L (+) − with stirring. 3.2 parts of ascorbic acid aqueous solution was added all at once. The time point 5 minutes after the batch addition of these is defined as “polymerization start”.

  A mixture of the following “polymerizable monomers etc.” and “emulsifier aqueous solution” was added over 5 hours from the start of polymerization, and the following “initiator aqueous solution” was added over 6 hours from the start of polymerization. While stirring, the internal temperature was maintained at 90 ° C. for 1 hour.

[Polymerizable monomers, etc.]
92.5 parts of styrene (1850.0 g)
Butyl acrylate 7.5 parts Acrylic acid 1.5 parts Trichlorobromomethane 0.6 parts

[Emulsifier aqueous solution]
20% DBS aqueous solution 1.0 part Demineralized water 67.0 parts

[Initiator aqueous solution]
8% by mass aqueous hydrogen peroxide solution 18.9 parts 8% by mass L (+)-ascorbic acid aqueous solution 18.9 parts

  After completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer primary particle dispersion H2. The volume average diameter (Mv) measured using Nanotrac was 290 nm, and the solid content concentration was 19.0% by mass.

<Preparation of colorant dispersion>
Carbon black (Mitsubishi Chemical Co., Ltd.) manufactured by a furnace method with a 300 L internal volume equipped with a stirrer (propeller blade) and a toluene extract having an ultraviolet absorbance of 0.02 and a true density of 1.8 g / cm ³ Mitsubishi Carbon Black MA100S) 20 parts (40 kg), 20% DBS aqueous solution 1 part, nonionic surfactant (manufactured by Kao Corp., Emulgen 120) 4 parts, ion-exchanged water 75 parts with an electric conductivity of 2 μS / cm In addition, it was predispersed to obtain a pigment premix solution. The volume average diameter (Mv) of carbon black in the dispersion after pigment premixing measured with Nanotrac was 90 μm.

The pigment premix solution was supplied as a raw material slurry to a wet bead mill and subjected to one-pass dispersion. The stator inner diameter was 75 mmφ, the separator diameter was 60 mmφ, the distance between the separator and the disk was 15 mm, and zirconia beads having a diameter of 100 μm (true density 6.0 g / cm ³ ) were used as the dispersing medium. Since the effective internal volume of the stator is 0.5 L and the filling volume of the media is 0.35 L, the media filling rate is 70% by mass. The pigment premix liquid is continuously supplied from the supply port at a supply speed of 50 L / hr by a non-pulsating metering pump, and the rotor rotation speed is constant (peripheral speed at the rotor tip is 11 m / sec), and continuously from the discharge port. To obtain a black colorant dispersion H. The volume average diameter (Mv) of the colorant dispersion H measured with Nanotrac was 150 nm, and the solid content concentration was 24.2% by mass.

<Manufacture of toner mother particles H>
Using the following components, toner base particles H were produced by carrying out the following aggregation processes (core material aggregation process / shell coating process), circularization process, washing process, and drying process.
Polymer primary particle dispersion H1 90 parts as solids (958.9 g as solids)
Polymer primary particle dispersion H2 10 parts colorant dispersion as solid content 4.4 parts 20% DBS aqueous solution as colorant solid content In the core material agglomeration step, 0.15 part 20% DBS aqueous solution as solid content In the circularization step , 6 parts as solids

○ Core material agglomeration step Polymer primary particle dispersions H1 and 20 in a mixer (volume 12 L, inner diameter 208 mm, height 355 mm) equipped with a stirrer (double helical blade), heating / cooling device and raw material / auxiliary charging device % DBS aqueous solution was charged and mixed uniformly at an internal temperature of 10 ° C. for 10 minutes. Then at an internal temperature of 10 ° C., allowed to stir at 280 rpm, 5 min 5 wt% aqueous solution of potassium sulfate _from continuously added over 1 minute 0.12 parts as K 2 SO _4, the colorant dispersion The mixture was continuously added over time and mixed uniformly at an internal temperature of 10 ° C.

  Thereafter, 100 parts of demineralized water was continuously added over 30 minutes, and then the internal temperature was raised to 48.0 ° C. over 67 minutes (0.5 ° C./min) while maintaining the rotational speed of 280 rpm. Next, after raising the temperature by 1 ° C. every 30 minutes (0.03 ° C./min), hold at 54.0 ° C., measure the volume median diameter (Dv50) using a multisizer, and grow to 5.15 μm. It was.

The stirring conditions at this time are as follows.
(A) Diameter of the stirring vessel (as a so-called general cylindrical shape): 208 mm
(B) Height of stirring container: 355 mm
(C) Peripheral speed at the tip of the stirring blade: 280 rpm, that is, 2.78 m / sec.
(D) Shape of stirring blade: Double helical blade (diameter 190mm, height 270mm, width 20mm)
(E) Position of the blades in the stirring vessel: 5 mm above the bottom of the vessel.

○ Shell coating step Thereafter, the polymer primary particle dispersion H2 was continuously added over 6 minutes with the internal temperature of 54.0 ° C. and the rotation speed of 280 rpm, and held as it was for 60 minutes. At this time, the Dv50 of the particles was 5.34 μm.

○ Circularization Step Subsequently, the temperature was raised to 83 ° C. while adding a mixed aqueous solution of 20% DBS aqueous solution (6 parts as a solid content) and 0.04 part of water over 30 minutes, and then 1 ° C. every 30 minutes. The temperature was raised to 88 ° C., and heating and stirring were continued under these conditions until the average circularity reached 0.939 over 3.5 hours. Then, it cooled to 20 degreeC over 10 minutes, and obtained the slurry. At this time, the Dv50 of the particles was 5.33 μm and the average circularity was 0.937.

Washing step The obtained slurry was extracted and suction filtered with an aspirator using 5 types C (Toyo Filter Paper No. 5C) filter paper. The cake remaining on the filter paper is transferred to a stainless steel container having an internal volume of 10 L equipped with a stirrer (propeller blade), and 8 kg of ion-exchanged water having an electric conductivity of 1 μS / cm is added and stirred uniformly at 50 rpm. Thereafter, stirring was continued for 30 minutes.

  After that, suction filtration was performed again with an aspirator using filter paper of 5 types C (No. 5C manufactured by Toyo Roshi Kaisha, Ltd.), and the solid matter remaining on the filter paper was again equipped with a stirrer (propeller blade) and had an electrical conductivity of 1 μS / The sample was transferred to a container with an internal volume of 10 L containing 8 kg of ion-exchanged water of cm, and the mixture was uniformly dispersed by stirring at 50 rpm and kept stirring for 30 minutes. When this process was repeated 5 times, the electrical conductivity of the filtrate was 2 μS / cm.

○ Drying step The solid material obtained here was spread on a stainless steel vat so as to have a height of 20 mm, and dried in a blow dryer set at 40 ° C. for 48 hours to obtain toner mother particles H.

<Manufacture of toner H>
External Addition Step To the obtained toner base particles H500 g, 8.75 g of Clariant H30TD silica is mixed as an external additive, and a 9 L Henschel mixer (Mitsui Henschel Mixer FM10B / I: manufactured by Mitsui Mining Co., Ltd.) is used. After mixing for 30 minutes at 3000 rpm using the upper blade Z type and lower blade A0 type, mixed with Maruo Calcium Co., Ltd. HAP-05NP calcium phosphate 1.40, mixed at 3000 rpm for 10 minutes, sieved with 200 mesh and toner H was obtained.

Analyzing Step The “volume median diameter (Dv50)” measured using a multisizer of the toner H obtained here is 5.33 μm, and “number% of toner having a particle size of 2.00 μm to 3.56 μm”. (Dns) "was 5.81%, the average circularity was 0.945, and the number variation coefficient was 18.9%.

○ Evaluation of actual image Toner H was tested by the evaluation method as described above. Initially, the image quality at 500 sheets and 1000 sheets was good. There was no toner scattering or charging roller contamination, and no image defects or other problems were found during the flow of the 5% printing rate pattern during the image check. The cleaning property was good.

Example 2
<Production of toner mother particle I>
<Preparation of wax / long-chain polymerizable monomer dispersion A1>
Paraffin wax (Nihon Seiki Co., Ltd. HNP-9, surface tension 23.5 mN / m, thermal characteristics: melting point peak temperature 82 ° C., melting heat 220 J / g, melting peak half width 8.2 ° C., crystallization temperature 66 ° C., Crystallization peak half-value width 13.0 ° C.) 27 parts (540 g), stearyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) 2.8 parts, 20 mass% sodium dodecylbenzenesulfonate aqueous solution (Daiichi Kogyo Seiyaku Co., Ltd., Neogen S20A) ( (Hereinafter abbreviated as “20% DBS aqueous solution”) 1.9 parts and 68.3 parts of demineralized water are heated to 90 ° C. and stirred for 10 minutes using a homomixer (Mark II f model, manufactured by Tokushu Kika Kogyo Co., Ltd.). did.

  Next, this dispersion was heated to 90 ° C., and circulation emulsification was started under a pressure condition of 25 MPa using a homogenizer (manufactured by Gorin, 15-M-8PA type). Dispersion was carried out until (Mv) reached 250 nm to prepare a wax / long-chain polymerizable monomer dispersion A1 (emulsion solid content concentration = 30.2 mass%).

<Preparation of polymer primary particle dispersion A1>
In a reactor (inner volume 21 L, inner diameter 250 mm, height 420 mm) equipped with a stirrer (three blades), a heating / cooling device, a concentrating device, and a raw material / auxiliary charging device, the wax / long-chain polymerizable unit is added. The monomer dispersion A1 (35.6 parts, 712.12 g) and 259 parts of demineralized water were charged, and the temperature was raised to 90 ° C. under a nitrogen stream while stirring.

  Thereafter, the mixture of the following “polymerizable monomers and the like” and “emulsifier aqueous solution” was added to the solution over 5 hours while continuing to stir the liquid. The time at which this mixture was started to be dropped was designated as “polymerization start”, and the following “initiator aqueous solution” was added over 4.5 hours from 30 minutes after the start of polymerization. Further, after 5 hours from the start of polymerization, the following “additional start” The agent aqueous solution ”was added over 2 hours, and the internal temperature was maintained at 90 ° C. for 1 hour while continuing stirring.

[Polymerizable monomers, etc.]
Styrene 76.8 parts (1535.0 g)
Butyl acrylate 23.2 parts Acrylic acid 1.5 parts Hexanediol diacrylate 0.7 parts Trichlorobromomethane 1.0 part

[Emulsifier aqueous solution]
20% DBS aqueous solution 1.0 part demineralized water 67.1 parts

[Initiator aqueous solution]
8% by mass aqueous hydrogen peroxide solution 15.5 parts 8% by mass L (+)-ascorbic acid aqueous solution 15.5 parts

[Additional initiator aqueous solution]
8 mass% L (+)-ascorbic acid aqueous solution 14.2 parts

  After the completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer primary particle dispersion A1. The volume average diameter (Mv) measured using Nanotrac was 280 nm, and the solid content concentration was 21.1% by mass.

<Preparation of polymer primary particle dispersion A2>
In a reactor (inner volume 21 L, inner diameter 250 mm, height 420 mm) equipped with a stirrer (three blades), a heating / cooling device, a concentrating device, and each raw material / auxiliary charging device, 1.0 part of a 20 mass% DBS aqueous solution Then, 312 parts of demineralized water was added, the temperature was raised to 90 ° C. under a nitrogen stream, and 3.2 parts of an 8% by mass hydrogen peroxide aqueous solution and 3.2 parts of an 8% by mass L (+)-ascorbic acid aqueous solution were stirred. Added all at once. The time point 5 minutes after the batch addition of these is defined as “polymerization start”.

  A mixture of the following “polymerizable monomers etc.” and “emulsifier aqueous solution” was added over 5 hours from the start of polymerization, and the following “initiator aqueous solution” was added over 6 hours from the start of polymerization. While stirring, the internal temperature was maintained at 90 ° C. for 1 hour.

[Polymerizable monomers, etc.]
92.5 parts of styrene (1850.0 g)
Butyl acrylate 7.5 parts Acrylic acid 0.5 part Trichlorobromomethane 0.5 part

[Emulsifier aqueous solution]
20% DBS aqueous solution 1.5 parts Demineralized water 66.0 parts

[Initiator aqueous solution]
8% by mass aqueous hydrogen peroxide solution 18.9 parts 8% by mass L (+)-ascorbic acid aqueous solution 18.9 parts

  After completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer primary particle dispersion A2. The volume average diameter (Mv) measured using Nanotrac was 290 nm, and the solid content concentration was 19.0% by mass.

<Production of toner mother particle I>
Using the following components, toner base particles I were produced by carrying out the following aggregation processes (core material aggregation process / shell coating process), circularization process, washing process, and drying process.
Polymer primary particle dispersion A1 95 parts as solid content (998.2 g as solid content)
Polymer primary particle dispersion A2 5 parts colorant dispersion as solids 6 parts 20% DBS aqueous solution as colorants solids 0.2 parts 20% DBS aqueous solution as solids in the core material agglomeration step 6 parts per minute

○ Core material agglomeration process Dispersion of primary polymer particles in a mixer (volume 12L, inner diameter 208mm, height 355mm) equipped with a stirrer (double helical blade), heating / cooling device, concentrator, and raw material / auxiliary charging device Liquid A1 and a 20% DBS aqueous solution were charged and mixed uniformly at an internal temperature of 7 ° C. for 5 minutes. Subsequently, while maintaining the internal temperature at 7 ° C. and continuing stirring at 250 rpm, 0.52 part of 5 mass% aqueous solution of ferrous sulfate was added as FeSO ₄ · 7H ₂ O over 5 minutes, and then the colorant The dispersion was added over 5 minutes, mixed uniformly at an internal temperature of 7 ° C., and a 0.5% by mass aqueous solution of aluminum sulfate was added dropwise over 8 minutes with the same conditions (solid to resin solids). Min is 0.10 parts). Thereafter, the internal temperature was raised to 55.0 ° C. while maintaining the rotational speed of 250 rpm, the volume median diameter (Dv50) was measured using a multisizer, and grown to 5.86 μm.

○ Shell coating step Thereafter, the polymer primary particle dispersion A2 was added over 3 minutes while maintaining the internal temperature at 55.0 ° C. and the rotation speed at 250 rpm, and held as it was for 60 minutes.

○ Circularization process Subsequently, the rotation speed was reduced to 150 rpm (a peripheral speed of 1.56 m / second at the tip of the stirring blade, a stirring speed reduced by 40% with respect to the rotation speed of the aggregation process), and then a 20% DBS aqueous solution (as solid content) 6 parts) was added over 10 minutes, and then the temperature was raised to 84 ° C. over 30 minutes, and heating and stirring were continued until the average circularity reached 0.942. Thereafter, it was cooled to 30 ° C. over 20 minutes to obtain a slurry.

Washing step The obtained slurry was extracted and suction filtered with an aspirator using 5 types C (Toyo Filter Paper No. 5C) filter paper. The cake remaining on the filter paper is transferred to a stainless steel container having an internal volume of 10 L equipped with a stirrer (propeller blade), and 8 kg of ion exchange water having an electric conductivity of 1 μS / cm is added and stirred uniformly at 50 rpm. Thereafter, stirring was continued for 30 minutes.

  Thereafter, the filter paper was suction filtered with an aspirator again using Type 5 C (Toyo Filter Paper No. 5C) filter paper, and the solid matter remaining on the filter paper was again equipped with a stirrer (propeller blade) and had an electrical conductivity of 1 μS / cm. It was transferred to a container with an internal volume of 10 L containing 8 kg of ion-exchanged water, and uniformly dispersed by stirring at 50 rpm and kept stirring for 30 minutes. When this process was repeated 5 times, the electrical conductivity of the filtrate was 2 μS / cm.

○ Drying step The solid material obtained here was spread on a stainless steel vat so that the height was 20 mm, and dried in a blow dryer set at 40 ° C. for 48 hours to obtain toner mother particles I.

<Manufacture of Toner I>
○ External Addition Step 500 g of the toner base particle I obtained is mixed with 7.70 g of Clariant H30TD silica as an external additive, and a 9 L Henschel mixer (Mitsui Henschel Mixer FM10B / I: manufactured by Mitsui Mining Co., Ltd.) is used. Then, using the upper blade Z type and the lower blade A0 type, after mixing at 3000 rpm for 30 minutes, mixed with Maruo Calcium Co., Ltd. HAP-05NP calcium phosphate 1.23, mixed at 3000 rpm for 10 minutes, and sieved with 200 mesh Separately, toner I was obtained.

Analyzing Step The “volume median diameter (Dv50)” measured using the toner I multisizer obtained here is 6.01 μm, and “number% of toner having a particle size of 2.00 μm to 3.56 μm”. (Dns) "was 2.57%, the average circularity was 0.945, and the number variation coefficient was 18.5%.

○ Evaluation of actual image Toner I was tested by the evaluation method as described above. Initially, the image quality at 500 sheets and 1000 sheets was good. There was no toner scattering or charging roller contamination, and no image defects or other problems were found during the flow of the 5% printing rate pattern during the image check. The cleaning property was good.

Example 3
<Manufacture of toner mother particle J>
The “core material aggregation process”, “shell coating process”, and “circularization process” in the aggregation process (core material aggregation process / shell coating process), circularization process, cleaning process, and drying process of “Manufacture of toner base particles I” The toner mother particles J were obtained in the same manner as in “Production of toner mother particles I” in Example 2, except that “A” was changed as follows.

○ Core material agglomeration step Polymer primary particle dispersion in a mixer (volume 12L, inner diameter 208mm, height 355mm) equipped with a stirrer (double helical blade), heating / cooling device, concentrating device and raw material / auxiliary charging device A1 and a 20% DBS aqueous solution were charged and mixed uniformly at an internal temperature of 7 ° C. for 5 minutes. Subsequently, while maintaining the internal temperature at 7 ° C. and adding stirring at 250 rpm, 0.52 parts of FeSO ₄ · 7H ₂ O as a 5 mass% aqueous solution of ferrous sulfate was added over 5 minutes, and then the colorant was dispersed. The liquid was added over 5 minutes, mixed uniformly at an internal temperature of 7 ° C., and a 0.5% by mass aqueous solution of aluminum sulfate was added dropwise over 8 minutes under the same conditions (solid content relative to resin solid content). 0.10 parts). Thereafter, the internal temperature was raised to 57.0 ° C. while maintaining the rotational speed of 250 rpm, and the volume median diameter (Dv50) was measured using a multisizer to grow it to 6.72 μm.

○ Shell coating step Thereafter, the polymer primary particle dispersion A2 was added over 3 minutes while maintaining the internal temperature at 57.0 ° C and the rotation speed at 250 rpm, and held as it was for 60 minutes.

○ Circularization process Subsequently, the rotational speed was reduced to 150 rpm (a peripheral speed of 1.56 m / second at the tip of the stirring blade, a stirring speed reduced by 40% with respect to the rotational speed of the aggregation process), and then a 20% DBS aqueous solution (solid content) 6 parts) was added over 10 minutes, and then heated to 87 ° C. over 30 minutes, and heating and stirring were continued until the average circularity reached 0.941. Thereafter, it was cooled to 30 ° C. over 20 minutes to obtain a slurry.

<Manufacture of toner J>
External addition process 500 g of the obtained toner base particles J are mixed with 6.25 g of Clariant H30TD silica as an external additive, and a 9 L Henschel mixer (Mitsui Henschel mixer FM10B / I: manufactured by Mitsui Mining Co., Ltd.) is used. After mixing for 30 minutes at 3000 rpm using the upper blade Z type and lower blade A0 type, mix with Maruo Calcium Co., Ltd. HAP-05NP calcium phosphate 1.00, mix at 3000 rpm for 10 minutes, and sieve with 200 mesh Separately, toner J was obtained.

Analyzing Step The “volume median diameter (Dv50)” measured using the toner J multisizer obtained here is 6.84 μm, and “number% of toner having a particle size of 2.00 μm to 3.56 μm”. (Dns) "was 1.81%, the average circularity was 0.942, and the number variation coefficient was 18.2%.

○ Evaluation of actual image Toner J was tested by the evaluation method as described above. Initially, the image quality at 500 sheets and 1000 sheets was good. There was no toner scattering or charging roller contamination, and no image defects or other problems were found during the flow of the 5% printing rate pattern during the image check. The cleaning property was good.

Comparative Example 1
<Manufacture of toner mother particles O>
In the agglomeration process (core material agglomeration process / shell coating process), circularization process, washing process, and drying process of “manufacturing toner mother particle H”, “core material aggregation process”, “shell coating process”, and “circularization process” The toner mother particles O were obtained in the same manner as in “Production of toner mother particles H” in Example 1 except that “” was changed as follows.

○ Core material agglomeration process Dispersion of primary polymer particles in a mixer (volume 12L, inner diameter 208mm, height 355mm) equipped with a stirrer (double helical blade), heating / cooling device, concentrator, and raw material / auxiliary charging device Liquid H1 and 20% DBS aqueous solution were charged and mixed uniformly at an internal temperature of 10 ° C. for 10 minutes. Subsequently, the mixture was stirred at 280 rpm at an internal temperature of 10 ° C., and 0.12 part of a 5 mass% aqueous solution of potassium sulfate was continuously added over 1 minute, and then the colorant dispersion was continuously added over 5 minutes. Mix uniformly at 10 ° C. Thereafter, 100 parts of demineralized water was continuously added over 30 minutes, and the internal temperature was raised to 34.0 ° C. over 40 minutes (0.6 ° C./min) with the rotation speed being 280 rpm. Subsequently, it hold | maintained for 20 minutes, the volume median diameter (Dv50) was measured using the multisizer, and it was made to grow to 3.81 micrometers.

○ Shell coating step Thereafter, the polymer primary particle dispersion H2 was added over 6 minutes while maintaining the internal temperature of 34.0 ° C and the rotation speed of 280 rpm, and the state was maintained for 90 minutes.

○ Circularization process Subsequently, 20% DBS aqueous solution (6 parts as solid content) was added over 10 minutes while maintaining the rotation speed at 280 rpm (the same stirring speed as the aggregation process rotation speed), and then 76 ° C over 30 minutes. The mixture was heated and stirred until the average circularity reached 0.962. Then, it cooled to 20 degreeC over 10 minutes, and obtained the slurry.

<Manufacture of toner N>
External Addition Step Subsequently, 100 parts of the toner base particles H of Example 1 and 1 part of the toner base particles O are mixed, and 500 g of this toner base particle mixture N is added in the same manner as in Example 1. Processing was performed to obtain toner N.

Analyzing Step The “volume median diameter (Dv50)” measured using the multi-sizer of toner N obtained here is 5.24 μm, and “number% of toner having a particle size of 2.00 μm to 3.56 μm”. (Dns) "was 6.81%, the average circularity was 0.946, and the number variation coefficient was 18.3%.

○ Evaluation of actual image Toner N was evaluated in the same manner as in Example 1. Initially, the image quality at 500 sheets and 1000 sheets was good. There was no toner scattering, and no image defects or other problems were observed during the flow of the 5% pattern during the image check. However, the toner was stained with toner and silica on the charging roller at 1000 sheets. Therefore, when a 5% printing rate pattern was further flowed, toner smear occurred on the white background of the printed material at about 1200 sheets. Toner contamination occurs at a period that coincides with the circumference of the charging roller, and is an image defect due to charging failure due to contamination of the charging roller. The evaluation was stopped here. Regarding the cleaning property, toner fine particles adhered to the surface of the cleaning blade, and the residual toner that passed through the cleaning blade was confirmed on the photoreceptor, which was bad.

Example 4
<Manufacture of toner mother particles K>
The “core material aggregation process”, “shell coating process”, and “circularization process” in the aggregation process (core material aggregation process / shell coating process), circularization process, cleaning process, and drying process of “Manufacture of toner base particles I” The toner base particles K were obtained in the same manner as in “Production of toner base particles I” in Example 2, except that “” was changed as follows.

○ Core material agglomeration step Polymer primary particle dispersion in a mixer (volume 12L, inner diameter 208mm, height 355mm) equipped with a stirrer (double helical blade), heating / cooling device, concentrating device and raw material / auxiliary charging device A1 and a 20% DBS aqueous solution were charged and mixed uniformly at an internal temperature of 7 ° C. for 5 minutes. Subsequently, while maintaining the internal temperature at 21 ° C. and continuing stirring at 250 rpm, 0.52 parts of FeSO ₄ .7H ₂ O as a 5 mass% aqueous solution of ferrous sulfate was added over 5 minutes, and then the colorant was dispersed. The liquid was added over 5 minutes, mixed uniformly at an internal temperature of 7 ° C., and a 0.5% by mass aqueous solution of aluminum sulfate was added dropwise over 8 minutes under the same conditions (solid content relative to resin solid content). 0.10 parts). Thereafter, the internal temperature was raised to 54.0 ° C. while maintaining the rotational speed of 250 rpm, the volume median diameter (Dv50) was measured using a multisizer, and grown to 5.34 μm.

○ Shell coating step Thereafter, the polymer primary particle dispersion A2 was added over 3 minutes while maintaining the internal temperature of 54.0 ° C and the rotation speed of 250 rpm, and the state was maintained for 60 minutes.

○ Circularization process Subsequently, the rotation speed was reduced to 220 rpm (circumferential speed 2.28 m / sec at the tip of the stirring blade, stirring speed reduced by 12% with respect to the aggregation process rotation speed), and then 20% DBS aqueous solution (as solid content) 6 parts) was added over 10 minutes, then the temperature was raised to 81 ° C. over 30 minutes, and heating and stirring were continued until the average circularity reached 0.942. Then, it cooled to 30 degreeC over 20 minutes, and obtained the slurry.

<Manufacture of toner K>
○ External addition step To 500 g of toner base particles K, 8.75 g of Clariant H30TD silica as an external additive is mixed, and a 9 L Henschel mixer (Mitsui Henschel mixer FM10B / I: Mitsui Mining Co., Ltd.) is used. After mixing for 30 minutes at 3000 rpm using blade Z type and lower blade A0 type, mix with Maruo Calcium Co., Ltd. HAP-05NP calcium phosphate 1.40, mix at 3000 rpm for 10 minutes, sieve through 200 mesh and toner K Got.

Analyzing Step The “volume median diameter (Dv50)” measured using the toner K multisizer obtained here is 5.45 μm, and “number% of toner having a particle size of 2.00 μm to 3.56 μm”. (Dns) "was 4.60%, the average circularity was 0.946, and the number variation coefficient was 19.8%.

○ Evaluation of actual image Toner K was tested by the evaluation method as described above. Initially, the image quality at 500 sheets and 1000 sheets was good. There was no toner scattering or charging roller contamination, and no image defects or other problems were found during the flow of the 5% printing rate pattern during the image check. The cleaning property was good.

Example 5
<Manufacture of toner mother particles L>
The “core material aggregation process”, “shell coating process”, and “circularization process” in the aggregation process (core material aggregation process / shell coating process), circularization process, cleaning process, and drying process of “Manufacture of toner base particles I” The toner base particles L were obtained in the same manner as in “Production of toner base particles I” in Example 2, except that “” was changed as follows.

○ Core material agglomeration process Dispersion of primary polymer particles in a mixer (volume 12L, inner diameter 208mm, height 355mm) equipped with a stirrer (double helical blade), heating / cooling device, concentrator, and raw material / auxiliary charging device Liquid A1 and a 20% DBS aqueous solution were charged and mixed uniformly at an internal temperature of 7 ° C. for 5 minutes. Subsequently, while maintaining the internal temperature at 21 ° C. and continuing stirring at 250 rpm, 0.52 parts of FeSO ₄ .7H ₂ O as a 5 mass% aqueous solution of ferrous sulfate was added over 5 minutes, and then the colorant was dispersed. The liquid was added over 5 minutes, mixed uniformly at an internal temperature of 7 ° C., and a 0.5% by mass aqueous solution of aluminum sulfate was added dropwise over 8 minutes under the same conditions (solid content relative to resin solid content). 0.10 parts). Thereafter, the internal temperature was raised to 55.0 ° C. while maintaining the rotational speed of 250 rpm, the volume median diameter (Dv50) was measured using a multisizer, and grown to 5.86 μm.

○ Shell coating step Thereafter, the polymer primary particle dispersion A2 was added over 3 minutes while maintaining the internal temperature at 55.0 ° C. and the rotation speed at 250 rpm, and held as it was for 60 minutes.

○ Circularization process Subsequently, the rotational speed was reduced to 220 rpm (a peripheral speed of 2.28 m / second at the tip of the stirring blade, a stirring speed reduced by 12% with respect to the rotational speed of the aggregation process), and then a 20% DBS aqueous solution (solid content) 6 parts) was added over 10 minutes, and then the temperature was raised to 84 ° C. over 30 minutes, and heating and stirring were continued until the average circularity reached 0.941. Thereafter, it was cooled to 30 ° C. over 20 minutes to obtain a slurry.

<Manufacture of toner L>
○ External addition process 500 g of the toner base particles L obtained are mixed with 7.70 g of Clariant H30TD silica as an external additive, and a 9 L Henschel mixer (Mitsui Henschel mixer FM10B / I: manufactured by Mitsui Mining Co., Ltd.) is used. Then, using the upper blade Z type and the lower blade A0 type, after mixing at 3000 rpm for 30 minutes, mixed with Maruo Calcium Co., Ltd. HAP-05NP calcium phosphate 1.23, mixed at 3000 rpm for 10 minutes, and sieved with 200 mesh Separately, toner L was obtained.

Analyzing Step The “volume median diameter (Dv50)” measured using a multisizer of the toner L obtained here is 5.98 μm, and “the number% of toner having a particle size of 2.00 μm to 3.56 μm”. (Dns) "was 3.98%, the average circularity was 0.942, and the number variation coefficient was 19.6%.

○ Evaluation of actual image Toner L was tested by the evaluation method as described above. Initially, the image quality at 500 sheets and 1000 sheets was good. There was no toner scattering or charging roller contamination, and no image defects or other problems were found during the flow of the 5% printing rate pattern during the image check. The cleaning property was good.

Example 6
<Manufacture of toner mother particles M>
The “core material aggregation process”, “shell coating process”, and “circularization process” in the aggregation process (core material aggregation process / shell coating process), circularization process, cleaning process, and drying process of “Manufacture of toner base particles I” The toner mother particles M were obtained in the same manner as in “Production of toner mother particles I” in Example 2, except that “A” was changed as follows.

○ Core material agglomeration process Dispersion of primary polymer particles in a mixer (volume 12L, inner diameter 208mm, height 355mm) equipped with a stirrer (double helical blade), heating / cooling device, concentrator, and raw material / auxiliary charging device Liquid A1 and a 20% DBS aqueous solution were charged and mixed uniformly at an internal temperature of 7 ° C. for 5 minutes. Subsequently, while maintaining the internal temperature at 21 ° C. and continuing stirring at 250 rpm, 0.52 parts of FeSO ₄ .7H ₂ O as a 5 mass% aqueous solution of ferrous sulfate was added over 5 minutes, and then the colorant was dispersed. The liquid was added over 5 minutes, mixed uniformly at an internal temperature of 7 ° C., and a 0.5% by mass aqueous solution of aluminum sulfate was added dropwise over 8 minutes under the same conditions (solid content relative to resin solid content). 0.10 parts). Thereafter, the internal temperature was raised to 57.0 ° C. while maintaining the rotational speed of 250 rpm, and the volume median diameter (Dv50) was measured using a multisizer to grow it to 6.76 μm.

○ Shell coating step Thereafter, the polymer primary particle dispersion A2 was added over 3 minutes while maintaining the internal temperature at 57.0 ° C and the rotation speed at 250 rpm, and held as it was for 60 minutes.

○ Circularization process Subsequently, the rotational speed was reduced to 220 rpm (a peripheral speed of 2.28 m / second at the tip of the stirring blade, a stirring speed reduced by 12% with respect to the rotational speed of the aggregation process), and then a 20% DBS aqueous solution (solid content) 6 parts) was added over 10 minutes, and then heated to 87 ° C. over 30 minutes, and heating and stirring were continued until the average circularity reached 0.941. Thereafter, it was cooled to 30 ° C. over 20 minutes to obtain a slurry.
<Manufacture of toner M>
○ External Addition Step To 500 g of toner base particles M, 6.25 g of Clariant H30TD silica as an external additive is mixed, and a 9 L Henschel mixer (Mitsui Henschel Mixer FM10B / I: Mitsui Mining Co., Ltd.) is used. After mixing at 3000 rpm for 30 minutes using blade Z type and lower blade A0 type, 1.00 g of HAP-05NP calcium phosphate manufactured by Maruo Calcium Co., Ltd. is mixed, mixed at 3000 rpm for 10 minutes, sieved with 200 mesh, and toner M Got.

Analyzing Step The volume median diameter (Dv50) measured by using the multisizer of the toner M obtained here is 6.88 μm, and “the number% of toner having a particle size of 2.00 μm to 3.56 μm (Dns ) ”Was 2.54%, the average circularity was 0.944, and the number variation coefficient was 20.5%.

○ Evaluation of actual image Toner M was tested by the evaluation method as described above. Initially, the image quality at 500 sheets and 1000 sheets was good. There was no toner scattering or charging roller contamination, and no image defects or other problems were found during the flow of the 5% printing rate pattern during the image check. The cleaning property was good.

Comparative Example 2
<Manufacture of toner mother particles Q>
The “core material aggregation process”, “shell coating process”, and “circularization process” in the aggregation process (core material aggregation process / shell coating process), circularization process, cleaning process, and drying process of “Manufacture of toner base particles I” The toner mother particles Q were obtained in the same manner as in “Production of toner mother particles I” in Example 2, except that “A” was changed as follows.

○ Core material agglomeration process Dispersion of primary polymer particles in a mixer (volume 12L, inner diameter 208mm, height 355mm) equipped with a stirrer (double helical blade), heating / cooling device, concentrator, and raw material / auxiliary charging device Liquid A1 and a 20% DBS aqueous solution were charged and mixed uniformly at an internal temperature of 7 ° C. for 5 minutes. Subsequently, while maintaining the internal temperature at 21 ° C. and continuously stirring at 250 rpm, 0.52 parts of FeSO ₄ .7H ₂ O as a 5 mass% aqueous solution of ferrous sulfate was added all at once in 5 minutes, and then the colorant was dispersed. The solution was added all at once in 5 minutes, mixed uniformly at an internal temperature of 7 ° C., and 0.5 mass% aqueous aluminum sulfate solution was added in 8 seconds under the same conditions (solid content relative to resin solid content) 0.10 parts). Thereafter, the internal temperature was raised to 57.0 ° C. while maintaining the rotational speed of 250 rpm, and the volume median diameter (Dv50) was measured using a multisizer to grow to 6.85 μm.

○ Shell coating step Thereafter, the polymer primary particle dispersion A2 was added all at once in 3 minutes while maintaining the internal temperature at 57.0 ° C. and the rotational speed of 250 rpm, and held as it was for 60 minutes.

○ Circularization process Subsequently, 20% DBS aqueous solution (6 parts as solid content) was maintained for 10 minutes while maintaining the rotational speed at 250 rpm (peripheral speed 2.59 m / sec at the tip of the stirring blade, the same stirring speed as the aggregation process rotational speed). Then, the temperature was raised to 87 ° C. over 30 minutes, and heating and stirring were continued until the average circularity became 0.942. Thereafter, the mixture was cooled to 30 ° C. over 20 minutes to obtain a slurry.

<Manufacture of toner Q>
External Addition Step To 500 g of toner mother particles Q, 6.25 g of Clariant H30TD silica as an external additive is mixed, and a 9 L Henschel mixer (Mitsui Henschel Mixer FM10B / I: Mitsui Mining Co., Ltd.) is used. After mixing for 30 minutes at 3000 rpm using the blade Z type and the lower blade A0 type, 1.00 g of HAP-05NP calcium phosphate manufactured by Maruo Calcium Co., Ltd. is mixed, mixed at 3000 rpm for 10 minutes, sieved with 200 mesh, and toner Q Got.

Analyzing Step The volume median diameter (Dv50) of the toner Q obtained here measured using a multisizer is 6.97 μm, and “the number% of toner having a particle size of 2.00 μm to 3.56 μm (Dns ) ”Was 4.64%, the average circularity was 0.940, and the number variation coefficient was 24.8%.

○ Evaluation of actual image When an actual image test was performed in the same manner as in Example 1, a stain occurred on a part of the rear end of the solid image during the initial check. When the printer was opened and examined, the toner was slightly attached to the cleaning blade at the position corresponding to the dirt. The photosensitive drum was removed, the cleaning blade was cleaned, and the toner was lightly dusted on the portion of the blade rubber that contacts the photosensitive drum, and the drum was mounted again to retake the image. Similar stains occurred on the same part. When several sheets were printed, no stain was generated, so the test was continued. Similarly, no failures occurred thereafter. When the 500 sheets were checked, the charging roller was contaminated with toner and external additives.

  When the test was further continued, toner smearing occurred on the white background of the printed material from about 900 sheets. Toner contamination occurred at a period that coincided with the circumference of the charging roller, and was an image defect due to charging failure due to contamination of the charging roller. The evaluation was stopped here.

Comparative Example 3
<Manufacture of toner mother particle R>
In the agglomeration process (core material agglomeration process / shell coating process), circularization process, washing process, and drying process of “manufacturing toner mother particle H”, “core material aggregation process”, “shell coating process”, and “circularization process” The toner mother particles R were obtained in the same manner as in “Production of toner mother particles H” in Example 1, except that “” was changed as follows.

○ Core material agglomeration process Dispersion of primary polymer particles in a mixer (volume 12L, inner diameter 208mm, height 355mm) equipped with a stirrer (double helical blade), heating / cooling device, concentrator, and raw material / auxiliary charging device Liquid H1 and 20% DBS aqueous solution were charged and mixed uniformly at an internal temperature of 10 ° C. for 10 minutes. Then at an internal temperature of 10 ° C., allowed to stir for 5 wt% aqueous solution of potassium sulfate from continuously added over 1 minute 0.12 parts as _K 2 SO ₄ at 310 rpm, over a period of 5 minutes colorant dispersion H Were added continuously and mixed uniformly at an internal temperature of 10 ° C.

  Thereafter, 100 parts of demineralized water was continuously added over 30 minutes, and the internal temperature was raised to 52.0 ° C. over 45 minutes (1.0 ° C./min) while maintaining the rotation speed at 310 rpm. Next, after raising the temperature by 1 ° C. every 30 minutes (0.03 ° C./min), hold at 54.0 ° C., measure the volume median diameter (Dv50) using a multisizer, and grow to 5.20 μm. It was.

○ Shell coating step Thereafter, the polymer primary particle dispersion H2 was continuously added over 6 minutes while maintaining the internal temperature of 54.0 ° C and the rotation speed of 310 rpm, and held as it was for 60 minutes. At this time, the Dv50 of the particles was 5.52 μm.

○ Circularization Step Subsequently, the mixture was heated to 88 ° C. while adding a mixed aqueous solution of 20% DBS aqueous solution (6 parts as solids) and 0.04 part of water over 30 minutes, and thereafter 1 ° C. every 30 minutes. The temperature was raised to 90 ° C., and heating and stirring were continued under these conditions until the average circularity reached 0.940 over 2 hours. Then, it cooled to 20 degreeC over 10 minutes, and obtained the slurry. At this time, the Dv50 of the particles was 5.88 μm and the average circularity was 0.943. The washing / drying steps were performed in the same manner as in Example 1.

<Manufacture of toner R>
External Addition Step After adding 7.5 g of Clariant H30TD silica as an external additive to 500 g of the obtained toner base particles R, and mixing with a 9 L Henschel mixer (Mitsui Mining Co., Ltd.) at 3000 rpm for 30 minutes, Maruo Toner R was obtained by mixing 1.2 g of HAP-05NP calcium phosphate manufactured by Calcium Co., Ltd., mixing at 3000 rpm for 10 minutes, and sieving with 200 mesh.

Analyzing Step The “volume median diameter (Dv50)” measured using the multi-sizer of the toner R obtained here is 5.40 μm, and “number% of toner having a particle size of 2.00 μm to 3.56 μm”. (Dns) "was 4.55%, the average circularity was 0.947, and the number variation coefficient was 24.2%.

○ Evaluation of actual image When an actual image test was performed in the same manner as in Example 1, the image quality at the initial time of 500 sheets and 1000 sheets was good. There was no toner scattering, and no image defects or other problems were found during the 5% pattern flow during the image check. Further, when a 5% printing rate pattern was passed, toner smearing occurred on a white background of printed matter at about 1200 sheets. Toner contamination occurs at a period that coincides with the circumference of the charging roller, and is an image defect due to charging failure due to contamination of the charging roller. The evaluation was stopped here. The cleaning performance was bad because toner particles adhered to the surface of the cleaning blade, and residual toner that passed through the cleaning blade was confirmed on the photoreceptor.

  The above results are summarized in Tables 1 and 2. Table 1 shows the composition, particle size distribution, shape, and physical properties of the toner, and Table 2 shows the actual image evaluation results of the toner.

  The toner used in the image forming apparatus of the present invention has particularly good cleaning properties, and the occurrence of stains, residual images (ghosts), blurring (solid followability), etc. on the white background of the image is small, and the charge amount distribution is sharp. Therefore, it has excellent image stability, narrow particle size distribution, and even if the toner particle size is reduced, there is little fine powder, so the bulk density is improved and the fixing property is good, so it can be used for general printers, copiers, etc. Of course, it is also widely used in image forming apparatuses and the like that have been developed in recent years with high resolution, long life, and high-speed printing.

1 Photoconductor (electrostatic image holding member)
2 Development roller (toner conveying member)
3 Doctor blade (Toner layer thickness regulating member)
4 Sponge roller (toner replenishment auxiliary member)
5 Agitator (stirring blade)
6 Toner 7 Toner hopper (toner storage room)
8 Cleaning blade

Claims (17)

A developing process for attaching toner to the electrostatic image on the surface of the electrostatic charge image holding member, a transfer process for transferring the toner on the electrostatic charge image holding member to a transfer material, and then, on the electrostatic charge image holding member in the transfer process. An image forming apparatus having a cleaning process for cleaning residual transfer toner remaining in the toner, wherein the toner used in the developing process satisfies all of the following (1) to (4) and (6): An image forming apparatus, wherein in the cleaning step, a transfer blade is cleaned by bringing a cleaning blade into contact with the electrostatic charge image holding member.
(1) The volume median diameter (Dv50) is 4.0 μm or more and 7.0 μm or less.
(2) The average circularity is 0.93 or more.
(3) The relationship between the volume median diameter (Dv50) of toner and the number% (Dns) of toner having a particle diameter of 2.00 μm to 3.56 μm satisfies Dns ≦ 0.233EXP (17.3 / Dv50).
(4) The number variation coefficient is 24.0% or less.
(6) The resin particles are fixed or adhered to the core particles,
Polymerization in which the core particles are composed of at least polymer primary particles and have a basic group and a polymerizable monomer having an acidic group in 100% by mass of the total polymerizable monomer constituting the binder resin as a resin fine particle. The ratio of the total amount of the polymerizable monomer is a polymerizable monomer having an acidic group and a basic group in 100% by mass of the total polymerizable monomer constituting the binder resin as the polymer primary particle constituting the core particle. It is smaller than the ratio of the total amount of monomers.   The relationship between the volume median diameter (Dv50) of toner and the number% (Dns) of toner having a particle diameter of 2.00 μm to 3.56 μm satisfies Dns ≦ 0.11EXP (19.9 / Dv50). The image forming apparatus described.   The relationship between the volume median diameter (Dv50) of toner and the number% (Dns) of toner having a particle diameter of 2.00 μm to 3.56 μm satisfies 0.0517EXP (22.4 / Dv50) ≦ Dns. The image forming apparatus according to claim 2.   4. The image forming apparatus according to claim 1, wherein the volume median diameter (Dv50) of the toner is 5.0 μm or more.   5. The image forming apparatus according to claim 1, wherein the number% (Dns) of toner having a particle diameter of 2.00 μm to 3.56 μm is 6% by number or less.   6. The image forming apparatus according to claim 1, wherein the toner is obtained by forming particles in an aqueous medium.   The image forming apparatus according to claim 1, wherein the toner is produced by an emulsion polymerization aggregation method. The image forming apparatus according to claim 1 , wherein the resin fine particles contain a wax. The image forming apparatus according to any one of claims 1 to 8 , wherein the wax is contained in an amount of 4 to 20 parts by weight with respect to 100 parts by weight of the toner. The image forming apparatus according to any one of claims 1 to 9 , wherein the cleaning blade is made of a material having a rubber hardness of 50 to 90. The image forming apparatus according to any one of claims 1 to 10 , wherein a developing process speed to the electrostatic charge image holding member is 80 mm / second or more. The image forming apparatus according to any one of claims 1 to claim 11 satisfies the following formula (5).
(5) Guaranteed lifetime number of sheets (sheets) x printing rate ≧ 400 (sheets) of the developer filled with developer The image forming apparatus according to any one of claims 1 to claim 12 resolution in the electrostatic image holding member on is 600dpi or more. The toner according to any one of claims 1 to 13 , wherein the toner used in the developing step is obtained without a step of removing a part of particles having a volume median diameter (Dv50) or less of the toner. The image forming apparatus described in 1. It has a charging step of charging an electrostatic image holding member, an image forming apparatus according to any one of claims 1 to claim 14 using a contact type charging member in the charging step. A developing process for attaching toner to the electrostatic image on the surface of the electrostatic charge image holding member, a transfer process for transferring the toner on the electrostatic charge image holding member to a transfer material, and then, on the electrostatic charge image holding member in the transfer process. (1) to (4) and ( 4) below, which are used in an image forming apparatus having a cleaning step of cleaning a transfer residual toner remaining on the toner by bringing a cleaning blade into contact with the electrostatic charge image holding member. 6) An electrostatic image developing toner characterized by satisfying all of the requirements.
(1) The volume median diameter (Dv50) is 4.0 μm or more and 7.0 μm or less.
(2) The average circularity is 0.93 or more.
(3) The relationship between the volume median diameter (Dv50) of toner and the number% (Dns) of toner having a particle diameter of 2.00 μm to 3.56 μm satisfies Dns ≦ 0.233EXP (17.3 / Dv50).
(4) The number variation coefficient is 24.0% or less.
(6) The resin particles are fixed or adhered to the core particles,
Polymerization in which the core particles are composed of at least polymer primary particles and have a basic group and a polymerizable monomer having an acidic group in 100% by mass of the total polymerizable monomer constituting the binder resin as a resin fine particle. The ratio of the total amount of the polymerizable monomer is a polymerizable monomer having an acidic group and a basic group in 100% by mass of the total polymerizable monomer constituting the binder resin as the polymer primary particle constituting the core particle. It is smaller than the ratio of the total amount of monomers. The electrostatic charge image developing toner according to claim 16 , wherein the cleaning blade is made of a material having a rubber hardness of 50 to 90.

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