JP2017116590A - toner - Google Patents

Abstract

Disclosed is a spherical toner that provides good cleaning properties, good fine line reproducibility, and can reduce contamination of a charging member even in an electrophotographic system that requires a long life.
[Solution]
A toner particle and a toner having fine particles on the surface of the toner particle, i) an average circularity of the toner particle is 0.960 or more, and ii) a wall surface friction angle θ of 10 ° or more and 15 ° or less. Iii) Total energy Et is 300 mJ or more and 600 mJ or less, iv) The fine particles contain fine particles A whose primary particles have a number average particle diameter (D1) of 200 nm or more and 500 nm or less, and the fine particles A are toner particles The liberation rate from is 10 mass% or more and 50 mass% or less. θ and Et are defined in the specification.
[Selection figure] None

Description

  The present invention relates to a toner used in an electrophotographic method, that is, an image forming method for visualizing an electrostatic charge image.

  Generally, in electrophotography, a photosensitive drum (image carrier) using a photoconductive substance is uniformly charged to a desired polarity and potential, and then image pattern exposure is performed on the photosensitive drum. An electrical latent image is formed. Thereafter, the toner is developed and visualized, and this is transferred and fixed on a transfer medium such as paper. Further, the toner remaining on the photosensitive drum after the transfer process is removed. The most widely used removal method is blade cleaning. That is, there is a method of scraping toner by pressing a blade-like member having elasticity such as rubber against the surface of the photosensitive drum.

  As a toner used in such electrophotography, a spherical toner has characteristics such as excellent transferability and fine line reproducibility. On the other hand, in a system in which toner is cleaned from a photosensitive drum by a cleaning blade, cleaning becomes difficult as the circularity of the toner increases. It is considered that the high circularity causes toner rolling, which is likely to be easily passed through the contact nip between the cleaning blade and the photosensitive member.

  In order to prevent poor cleaning with respect to the spherical toner, Patent Document 1 proposes the following method. That is, this is a method of stabilizing cleaning by forming a layer due to accumulation of external additives at the blade edge portion and forming a layer blocking toner particles.

  Patent Document 2 proposes a means for reducing the residual toner and improving the cleaning property by reducing the adhesive force by embedding an external additive in the spherical toner.

  Patent Document 3 proposes a means for improving toner cleaning properties by forming a toner reservoir in a cleaning unit.

JP 2002-318467 A JP 2012-68325 A JP 2008-276005 A

  In the case of the method of Patent Document 1, an external additive for forming a toner blocking layer may slip through the blade and contaminate the charging member. If a mechanism for cleaning the charging member is provided to prevent this, the mechanism becomes complicated or the cost increases. Especially in a system that requires a long life, the formation of a blocking layer becomes insufficient due to the external additive being embedded in the toner during long-term use and the surface of the photosensitive drum being rough (wear unevenness). Sometimes. As a result, toner cleaning becomes difficult.

  In the technique of Patent Document 2, it cannot be said that it is easy to obtain a sufficient cleaning property in a toner having a high shape factor SF1 and high circularity.

  In the method of Patent Document 3, it is necessary to attach a member for forming a toner reservoir for cleaning.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a spherical toner that provides good cleaning properties, good fine line reproducibility, and can reduce contamination of a charging member even in an electrophotographic system that requires a long life. is there.

According to one aspect of the present invention, a toner having toner particles and fine particles on the surface of the toner particles,
i) The average circularity of the toner particles is 0.960 or more,
ii) The wall friction angle θ calculated from the following equation of the toner is 10 ° or more and 15 ° or less,
θ = τ / σ
(Σ represents a vertical load (kPa) when a disc-shaped disk is allowed to enter a toner powder layer formed by applying a vertical load of 9.0 kPa,
τ represents the shear stress obtained when a disk-shaped disk is penetrated into the toner powder layer and rotated at (π / 10) rad / min at (π / 36) rad, and the measurement is performed at σ = 3 kPa. . )
iii) A propeller blade rotating at a peripheral speed of 100 mm / s at the outermost edge is vertically entered into the toner powder layer formed by applying a load of 3 kPa, and measured from a position 100 mm from the bottom of the powder layer. The total energy Et, which is the sum of the rotational torque and the vertical load of the propeller blade, obtained when starting from the bottom to a position of 10 mm from the bottom is 300 mJ or more and 600 mJ or less,
iv) The fine particles contain fine particles A having a number average particle diameter (D1) of primary particles of 200 nm or more and 500 nm or less, and the fine particles A have a liberation rate from the toner particles of 10% by mass or more and 50% by mass. Is
A toner is provided.

  According to the present invention, it is possible to provide a spherical toner which can provide good cleaning properties, good fine line reproducibility, and can reduce contamination of a charging member even in an electrophotographic system that requires a long life. it can.

It is a figure which shows the propeller type | mold blade in a powder fluidity | liquidity analyzer, a is the figure which looked at the long side of the blade in front, and b is the schematic diagram which looked at the blade outermost edge part in the front. It is a schematic diagram which shows the disk shaped disk for measuring a wall surface friction angle, a is a bird's-eye view, b is a bottom view. It is the schematic which shows an example of an external addition apparatus. It is a figure for demonstrating four area | regions utilized in measurement of the abundance rate etc. of microparticles | fine-particles.

  The present invention relates to a toner particle and a toner having fine particles on the surface of the toner particle. This toner satisfies the following conditions i to iv.

  i) The average circularity of the toner particles is 0.960 or more.

ii) The following equation for toner: θ = τ / σ
The wall friction angle θ calculated from the above is 10 ° or more and 15 ° or less.
Here, σ represents a vertical load (kPa) when a disc-shaped disk is allowed to enter a toner powder layer formed by applying a vertical load of 9.0 kPa.
τ represents the shear stress obtained when a disk-like disk is penetrated into the toner powder layer and rotated at (π / 10) rad / min at (π / 36) rad, and this measurement is performed at σ = 3 kPa. Do.

  iii) The total energy Et is 300 mJ or more and 600 mJ or less. Et is measured by allowing a propeller blade rotating at a circumferential speed of 100 mm / s at the outermost edge to vertically enter a toner powder layer formed by applying a load of 3 kPa. At that time, the measurement is started from the position of 100 mm from the bottom surface of the powder layer, and the sum of the rotational torque and the vertical load of the propeller type blade obtained when the powder layer is moved to the position of 10 mm from the bottom surface is Et. .

  iv) The fine particles present on the toner surface contain fine particles A having a primary particle number average particle diameter (D1) of 200 nm or more and 500 nm or less. The fine particles A have a liberation rate from the toner of 10% by mass or more and 50% by mass or less.

  The cleaning unit prevents the toner from slipping through by pressing a cleaning blade against the photosensitive drum. Conventionally, in order to satisfy the cleaning performance of the spherical toner, the configuration has been such that the spherical toner is less likely to enter by increasing the contact pressure of the cleaning blade against the photosensitive drum. However, when the contact pressure of the cleaning blade is increased, the photosensitive drum is easily worn and a new problem arises. Especially for long-life systems, there were still problems.

  Therefore, the present inventors paid attention to the state of toner in the cleaning blade portion. In the cleaning unit, the toner is in contact with the photosensitive drum in a state where a load is applied due to the force applied to the blade edge portion, and the toners are in a compacted state. The spherical toner has a feature that a good transferability can be obtained because the surface has little unevenness, but on the other hand, when a load is applied, the contact area with the photosensitive drum becomes high and the frictional force becomes high. As a result, it becomes difficult to clean the photosensitive drum. Thus, it has been found that reducing the frictional force between the compacted toner and the flat plate is important for improving the cleaning property of the toner.

  In order to reduce the frictional force between the toner and the flat plate in the compacted state, it can be reduced by coating the toner particle surface with an external additive. However, the inventors have clarified that not only the frictional force between the toner and the flat plate but also the ease of loosening between the toners is important in order to improve the cleaning property. In the cleaning portion where the toner is in a compacted state, if the toners are not easily loosened, the toner pushes up the cleaning blade, and as a result, the toner cleaning performance deteriorates.

  In order to develop the above characteristics with a spherical toner, the present inventors have intensively studied. As a result, it has been found that the toner needs to satisfy the above-mentioned characteristics ii and iii.

  The reason why the present inventors have come into the range of the above-mentioned toner physical property values in order to obtain good cleaning properties will be described below. It has been found that irregularly shaped toner particles exhibit good cleaning properties. As a result of various studies on the physical properties of these toners, it was found that the index (Et) of the ease of loosening between the toner and the toner is appropriate. On the other hand, it was found that the spherical toner has a high index (Et) of the ease of loosening between the toner and the toner. As a result of studying the difference, it was found that the spherical toner has a smooth surface, and thus is caused by surface contact between the toner and the toner. Therefore, in order to change the contact between the toner and the toner from surface contact to point contact, investigations were made by paying attention to an external additive having a large particle diameter.

  As a result, when the factor that the irregularly shaped toner is easily loosened was examined, it was found that the toner surface had irregularities. Therefore, even with spherical toner particles, it has been considered that the ease of loosening between toner toners can be controlled by externally adding a large particle size external additive. Therefore, when the particle size of the external additive was examined, the toner-to-toner was easily loosened when the particle size was about 100 nm, but the sliding property between the toner and the flat plate was insufficient and the service life was long. It was insufficient to satisfy the cleaning property in the system. Therefore, as a result of further investigations with a larger particle size of the external additive, it was found that the toner-to-toner is less likely to be loosened. As a result of examining the reason, it was found that the external additive was not sufficiently fixed. For this reason, it was necessary to fix an external additive, and it was found that the fine particles A had a liberation rate from the toner of 10% by mass or more and 50% by mass or less.

  Here, free means that fine particles are separated from the toner surface. When the fine particles are released from the toner surface, the fine particles are likely to aggregate with each other or to move to a member in an image forming apparatus such as a printer, and easily cause various member contamination in the electrophotographic process. There is a problem. The term “transfer” here means that fine particles move to a member in the image forming apparatus such as a printer.

  The fine particles used as the external additive must contain fine particles A having a primary particle number average particle diameter (D1) of 200 nm to 500 nm.

  With such a toner, both the ease of toner-toner loosening and the slipperiness between the toner and the flat plate can be achieved, and as a result, good cleaning and transferability can be satisfied even in a long-life system. . The number average particle diameter (D1) of the primary particles of the fine particles is preferably 250 nm or more and 400 nm or less, and the liberation rate is preferably 15% by mass or more and 40% by mass or less.

<Measurement method of wall friction angle>
The wall friction angle measured when the disc-shaped disk is pressed against the surface of the compacted toner powder layer is a powder rheometer RH4 (trade name, manufactured by Malvern, hereinafter abbreviated as “FT4”). Is measured). At that time, a rotary propeller blade and a disk-shaped disk blade (disk-shaped disk) are used.

  For the rotary propeller blade (hereinafter sometimes abbreviated as “propeller”), a 48.0 mm diameter blade dedicated to FT4 measurement is used. As shown in FIG. 1, the propeller blade is a blade plate of 48 mm × 10 mm. A rotation axis exists in the normal direction at the center of the blade plate (a shaft body is provided). The blade plate is smoothly twisted counterclockwise so that both outermost edge portions (24 mm from the rotating shaft) are 70 ° and a portion 12 mm from the rotating shaft is 35 °. Here, “counterclockwise” means counterclockwise when the blade plate is viewed from the outer edge of the blade plate toward the rotation axis. The material of the blade plate is stainless steel.

  For the measurement of the wall friction angle, a disk-shaped disk blade (see FIG. 2: diameter 48.0 mm, thickness 1.5 mm, made of stainless steel, hereinafter may be abbreviated as “disk”). Use. Note that a laminated sheet having a NANOS layer (a layer obtained by thinning a fluorine-based polymer in a nano order) on the surface of the disk (the surface in contact with the toner) is pasted and used. This laminated sheet is a sheet laminated in the order of (1) adhesive layer, (2) PET film, (3) antireflection layer, and (4) NANOS layer. The ten-point average roughness Rz (according to JIS B0601: 1982) of the surface of this laminated sheet is about 0.060 μm (measured with a surface roughness measuring device Surfcoder SE3500 (trade name) manufactured by Kosaka Laboratory Ltd.). This laminated sheet can be obtained from Katsurayama Technology Co., Ltd.

  As a method of attaching the sheet, it is attached to the disk surface on the side pressed against the powder layer. At this time, a sheet is pasted except for a screw hole (shown in FIG. 2b, diameter 4.0 mm) for fixing the disk to the rotating shaft. The purpose of sticking this sheet is to make it easy to measure the friction between the toner powder layer and the flat plate by using a slippery material for the disc-like disk.

  When measuring the wall friction angle, 60 g of toner left in a 23 ° C., 60% RH (relative humidity) environment for 3 days or more in a cylindrical split container with a diameter of 50 mm and a volume of 190 ml dedicated to FT4 measurement is put into powder. Layer (toner powder layer). This split container (hereinafter sometimes abbreviated as container) has a height of 43 mm from the bottom surface to the split part, and is made of glass.

(1) Conditioning operation A propeller is advanced from the powder layer surface to a position 10 mm from the bottom surface of the powder layer. At this time, the rotational speed of the outermost edge of the propeller is 60 (mm / sec) in the clockwise direction (the direction in which the powder layer is loosened by the rotation of the propeller) with respect to the powder layer surface, Rotate the propeller. In addition, the vertical approach speed of the powder layer is 5 (the angle formed by the trajectory drawn by the outermost edge of the moving propeller and the surface of the powder layer (hereinafter may be abbreviated as “the formed angle”)) of 5 ( deg).

  Thereafter, the propeller is further advanced to a position of 1 mm from the bottom surface of the powder layer. At this time, the propeller is rotated in the clockwise rotation direction with respect to the powder layer surface at a rotation speed at which the peripheral speed of the outermost edge portion of the propeller is 40 (mm / sec). Further, the speed of approaching the powder layer in the vertical direction is set to a speed at which the “angle” is 2 (deg).

  Thereafter, the propeller is extracted by moving the propeller to a position of 80 mm from the bottom surface of the powder layer. At this time, the propeller is rotated in the counterclockwise rotation direction with respect to the powder layer surface at a rotation speed at which the peripheral speed of the outermost edge portion of the propeller is 60 (mm / sec). Further, the extraction speed from the powder layer is set to a speed at which the “angle” is 5 (deg).

  When the extraction is completed, the toner attached to the propeller is wiped off by rotating the propeller clockwise and counterclockwise alternately.

(2) Toner Compaction Operation Here, a compression test piston (diameter 48.0 mm, height 20 mm, lower mesh tension) is used instead of the propeller blade. The compression test piston is moved vertically downward at a rate of 0.5 mm / sec from a height of 80 mm from the bottom surface of the powder layer to enter the powder layer. When a load of 0.55 kPa is applied to the powder layer surface, the blade approach speed is changed to 0.04 mm / sec. When 9.0 kPa was applied to the surface of the powder layer, the piston was stopped, and compaction was performed for 60 seconds, and then the piston was moved vertically upward.

(3) Split operation A toner powder layer having a constant volume (85 ml) is formed by scraping the toner powder layer at the split portion of the above-described FT4 measurement container and removing the toner above the toner powder layer.

(4) Measurement operation Subsequently, the wall friction angle θ is obtained by the following operation.

  (4.1) When the compression test piston is replaced with the disk which is a blade for wall friction measurement, the disk is lowered at 0.08 (mm / sec), and when a load of 9.0 kPa is applied to the powder layer Stop the disk. This reconsolidates the powder layer. In this operation, the disk is not rotated.

  (4.2) Thereafter, the disk is rotated (π / 3) rad clockwise at a speed of (π / 10) rad / min with respect to the powder layer surface, and pre-shearing is applied to the powder layer surface.

  (4.3) Next, the rotation of the disk is stopped to remove the shear load, and only the vertical load σ3.0 kPa is applied to enter the standby state for 25 (sec).

  (4.4) Calculated from the rotational torque when the disk is rotated (π / 10) rad / min (π / 36) rad in the clockwise rotation direction with respect to the toner powder layer surface after standby. The shear stress τ is measured.

  (4.5) Using the value of the vertical load σ (3 kPa) and the obtained shear stress τ, obtain the wall friction angle θ from the equation “θ = τ / σ”.

  The wall friction angle indicates the friction resistance between the surface of the toner powder layer and the flat plate. When the wall friction angle is large, the friction resistance is high, and when the wall friction angle is small, the friction resistance is small. When the wall friction angle is smaller than 10 °, the frictional resistance with the drum is too small, and the toner scatters easily during transfer. On the other hand, if it is larger than 15 °, the frictional resistance becomes high, and it becomes difficult to scrape off the toner with a blade during cleaning, and the cleaning performance deteriorates. The wall friction angle is preferably 11 ° or more and 14 ° or less. The reason why the vertical load at the time of measurement is 3.0 kPa is that there is little adhesion of toner to the sheet attached to the surface of the disk blade.

<Measurement Method of Total Energy Et of Toner Powder Layer>
Et (mJ) is measured using the above-described powder rheology analyzer, powder rheometer FT4 (trade name).

  In all operations, the same rotary propeller blade as that used for measuring the wall friction angle is used. As the measurement container, a cylindrical split container dedicated to FT4 (model number: C203, material: glass, diameter 50 mm, volume 160 ml, height 82 mm from the bottom surface to the split part, hereinafter may be abbreviated as container) is used. .

  In measuring the total energy Et, 100 g of toner left in an environment of a temperature of 23 ° C. and 60% RH for 3 days or more is placed in the measurement container to form a toner powder layer.

(1) Conditioning operation (1a) The propeller is rotated clockwise with respect to the surface of the powder layer so that the peripheral speed of the outermost edge of the propeller is 60 mm / sec (the direction in which the powder layer is loosened by the rotation of the propeller). Rotate. This propeller is moved from the powder layer surface to the toner powder layer at an approach speed at which the “angle formed” (angle formed by the outermost edge of the moving propeller and the surface of the powder layer) is 5 °. Enter vertically from the bottom to a position of 10 mm.

  Thereafter, the toner powder is rotated while rotating clockwise with respect to the powder layer surface so that the peripheral speed of the outermost edge of the propeller is 60 mm / sec by changing to an approach speed at which the “angle” is 2 °. The propeller is advanced to a position 1 mm from the bottom of the layer.

  Further, while rotating clockwise with respect to the surface of the powder layer so that the “round angle” is 5 ° and the peripheral speed of the outermost edge portion of the propeller is 60 mm / sec, Extraction is performed by moving the propeller to a position of 100 mm. When the extraction is completed, the toner attached to the blade is wiped off by rotating the blade alternately in small clockwise and counterclockwise directions.

  (1b) The operation of 1a is repeated 5 times to remove air taken in the toner powder layer.

(2) Compression operation The toner powder layer subjected to the conditioning operation in (1) is compressed by applying a pressure of 3 kPa. Specifically, a compression test piston (diameter 48 mm, height 20 mm, lower mesh tension) is used instead of the propeller blade. The piston is lowered at 0.1 mm / s to compress the toner. When the load on the piston reaches 3 kPa, the descent is stopped and held for 60 seconds as it is to form a compressed powder layer, and then the piston is raised.

(3) Split operation The conditioned and compressed powder layer is cut off at the split portion of the FT4 container, and the toner on the upper part of the powder layer is removed. That is, a powder layer having a height of 82 mm is obtained. By this operation, the volume of the toner powder layer can be made the same for each measurement.

(4) Et measurement operation (4a) The propeller is rotated counterclockwise with respect to the surface of the powder layer so that the peripheral speed of the outermost edge of the propeller is 100 mm / sec. Rotate in the direction). The propeller is advanced in the vertical direction from the powder layer surface to a position 10 mm from the bottom surface of the toner powder layer at an approach speed at which the “angle” is 5 °.

  After that, the propeller is rotated clockwise with respect to the powder layer surface so that the peripheral speed of the outermost edge of the propeller is 60 mm / sec. The speed is 2 °, and the powder layer is entered from the bottom surface to a position of 1 mm.

  Further, the propeller is moved up to a position of 100 mm from the bottom surface of the powder layer at a speed at which the “angle” is 5 ° so that the peripheral speed of the outermost edge is 60 mm / sec, and is extracted.

  When the extraction is completed, the toner attached to the propeller is wiped off by rotating the propeller clockwise and counterclockwise alternately.

(4b) Measurement of Et The rotational torque and vertical load applied to the propeller, measured when the propeller is moved from the position of 100 mm to the position of 10 mm from the bottom surface of the toner powder layer, are converted into energy, and the total energy is calculated from the sum. (Et) was obtained.

  The total energy Et indicates the ease of loosening between the toners of the compacted toner powder layer, and is a physical property value indicating that it is easy to loosen when Et is low, and is difficult to loosen when Et is high. When Et is larger than 600 mJ, the toner exerts a force to push up the cleaning blade at the cleaning nip portion, and the cleaning property is deteriorated. When Et is smaller than 300 mJ, the toner easily moves at the nip portion of the cleaning blade, and the toner slips through the cleaning blade, so that the cleaning property is deteriorated. Et is more preferably 350 mJ or more and 550 mJ or less.

<Presence of fine particles>
Furthermore, as a result of studies to make it possible to provide a toner that can function as a spacer particle and can be highly durable, the present inventor has found that the presence state of fine particles on the toner particle surface is significant. It was.

  That is, in the reflected electron image of the toner surface photographed with a scanning electron microscope at a magnification of 20,000 times, the average value of the abundance of fine particles having a particle diameter of 200 nm or more and 500 nm or less in each of the four areas is obtained. The fine particle abundance Er on one toner surface is defined as Er. At this time, it is preferable that the average value of Er is 5 area% or more and 40 area% or less. This is because by limiting to fine particles having a particle diameter of 200 nm or more and 500 nm or less, it has been found that it is possible to express slipperiness with the surface of the photoreceptor and to further reduce the fine line reproducibility and contamination of the charging member.

Definition of the above four areas:
In the reflected electron image of the toner, a string that gives the maximum length is a line segment A, and two straight lines that are parallel to the line segment A and 1.5 μm apart from the line segment A are a straight line B and a straight line C. A straight line passing through the midpoint of the line segment A and orthogonal to the line segment A is defined as a straight line D, and two straight lines parallel to the straight line D and separated from the straight line D by 1.5 μm are defined as a straight line E and a straight line F. Four regions each formed by a line segment A and straight lines B, C, D, E, and F, each having a square with a side length of 1.5 μm.

<Measurement method of abundance ratio of fine particles>
A reflected electron image of one toner is observed with a scanning electron microscope “S-4800” (trade name; Hitachi, Ltd.) at a magnification of 20,000 times. In the reflected electron image of the toner, as shown in FIG. 4, the maximum length of the toner string is a line segment A, and two straight lines parallel to the line segment A and 1.5 μm apart from the line segment A are straight lines. Let B and straight line C. A straight line passing through the midpoint of the line segment A and orthogonal to the line segment A is defined as a straight line D, and two straight lines parallel to the straight line D and separated from the straight line D by 1.5 μm are defined as a straight line E and a straight line F. Four regions each defined by a line segment A and straight lines B, C, D, E, and F, each having a side length of 1.5 μm, are defined.

The area occupied by fine particles having a particle size of 200 nm or more and 500 nm or less in each of the four regions was calculated using image processing software “Image-Pro Plus 5.1J” (trade name, manufactured by Media Cybernetics). For each of the four regions, the ratio of the calculated area to the area of the region (calculated area ÷ 2.25 μm ² ) was defined as the existence ratio in each region. Then, as an average value of the abundance ratios in the four areas, a fine particle abundance ratio (abundance ratio of fine particles having a particle diameter of 200 to 500 nm) Er is obtained.

  This operation was performed on 50 toners, and the average value of Er was defined as the average abundance of fine particles having a particle diameter of 200 to 500 nm. The “fine particle abundance ratio” shown in Table 2 means this average abundance ratio (average value of Er).

  When the average abundance (average value of Er) is 5 area% or more, it is easy to obtain good sliding properties between the toner and the flat plate, and it is easy to obtain good cleaning properties. Further, when the average abundance ratio is 40 area% or less, the gap between the toner and the toner is easily loosened, and it is easy to obtain a good cleaning property.

<Coefficient of variation of the number of particles present>
It is preferable that the coefficient of variation (the calculation method will be described in detail below) calculated from the number of fine particles having a particle diameter of 200 nm or more and 500 nm or less in the four regions is 0.5 or less.
When the coefficient of variation is high, the dispersion of the adhesion state of the fine particles is high, and the sliding property between the toner and the flat plate tends to be small.

<Measurement method of coefficient of variation of the number of particles present>
The reflected electron image of the toner is observed with a scanning electron microscope “S-4800” (trade name; Hitachi, Ltd.) at a magnification of 20,000 times. In the reflected electron image of the toner, four regions each having a side length of 1.5 μm and defined by the above-described line segment A and straight lines B, C, D, E, and F are defined.

By counting the number of fine particles having a particle diameter of 200 nm to 500 nm, the number of fine particles having a particle diameter of 200 to 500 nm in each region is calculated. By adding the number of existing particles in each region, the number of existing particles En having a particle diameter of 200 to 500 nm on one toner surface is calculated. That is, the sum of the four existing numbers for each region is defined as the number of fine particles existing on one toner surface En. This operation was performed for 50 toners, the average value and standard deviation of En were calculated, and the coefficient of variation was obtained from the following equation.
Coefficient of variation = (standard deviation of En / average value of En).

<Material of fine particles>
Fine particles having a primary particle number average particle diameter (D1) of 200 nm or more and 500 nm or less exist on the toner particle surface. The fine particles are not particularly limited as long as the number average particle diameter (D1) of the primary particles is within this range. Examples of the fine particles include inorganic fine particles such as silica, alumina, and titanium oxide, resin fine particles, and organic-inorganic composite particles.

  Any silica produced using a conventionally known technique such as a gas phase decomposition method, a combustion method, or a deflagration method can be used. For example, a sol-gel obtained by a known sol-gel method in which a solvent is removed from a silica sol suspension obtained by hydrolyzing and condensing an alkoxysilane with a catalyst in an organic solvent in which water is present, followed by drying to form particles. Silica can be used. The organic-inorganic composite fine particles can be produced, for example, according to the description of the examples in WO2013 / 063291.

  In order to achieve both ease of loosening between the toner and the toner and slipperiness of the toner and the flat plate, the particle size distribution of the fine particles having a primary particle number average particle diameter (D1) of 200 to 500 nm is preferably monodisperse. When the particle size distribution of the fine particles is monodispersed, the fine particles are easily dispersed uniformly on the surface of the toner particles.

  The full width at half maximum of the particle size distribution of the fine particles A is preferably 40 nm or less because the coefficient of variation of the number of fine particles present is small. More preferably, it is 30 nm or less.

  Furthermore, the silica surface obtained by the sol-gel method may be used after being hydrophobized, and a silane compound is preferably used as the hydrophobizing agent. Examples of silane compounds include monomethylsilanes such as hexamethyldisilazane, trimethylchlorosilane and triethylchlorosilane, monoalkoxysilanes such as trimethylmethoxysilane and trimethylethoxysilane, monoaminosilanes such as trimethylsilyldimethylamine and trimethylsilyldiethylamine, and trimethylacetoxysilane. Of monoacyloxysilane.

  The content of fine particles having a number average particle diameter (D1) of primary particles in the toner of 200 to 500 nm is preferably 0.5 parts by mass or more and 5.0 parts by mass or less with respect to 100 parts by mass of the toner particles. In order to make the abundance ratio of the fine particles A within a preferable range, the above content is preferable.

<Other external additives>
Fine particles having a number average particle diameter (D1) of primary particles of 200 nm to 500 nm, that is, fine particles A, are external additives in the toner. As an external additive, fine particles (referred to as a second external additive) other than the fine particles may be added to the toner.

  However, from the viewpoint of preventing the spacer effect from being reduced by the fine particles A, it is preferable to add only the fine particles A without adding an external additive having a small number average particle diameter.

  The second external additive is preferably a silica fine particle or titania fine particle subjected to a hydrophobic treatment. The number average particle diameter is preferably 5 nm or more and 40 nm or less. Examples of the hydrophobizing treatment include treatment with an organosilicon compound, silicone oil, long chain fatty acid and the like.

  Examples of the organosilicon compound include hexamethyldisilazane, trimethylsilane, trimethylethoxysilane, isobutyltrimethoxysilane, trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, and hexamethyl. Examples thereof include disiloxane. These may be used alone or as a mixture of two or more.

  Examples of the silicone oil include dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene modified silicone oil, chlorophenyl silicone oil, and fluorine modified silicone oil.

<Manufacture of toner particles>
The method for producing toner particles is not particularly limited as long as the method can produce toner particles having a circularity of 0.960 or more. As a method for producing a toner having a high degree of circularity, a method for producing toner particles directly in a hydrophilic medium such as a suspension polymerization method, an interfacial polymerization method or a dispersion polymerization method (hereinafter also referred to as a polymerization method), pulverization, etc. For example, the toner may be spheroidized by heat.

  Among them, toner particles produced by a suspension polymerization method are preferable because the individual particles are substantially spherical and the distribution of charge amount is relatively uniform, so that high transferability can be realized.

  The suspension polymerization method is a method for producing toner particles through at least a granulation step and a polymerization step. In the granulation step, a polymerizable monomer composition having at least a polymerizable monomer, a colorant, wax, and the like is dispersed in an aqueous medium to produce droplets of the polymerizable monomer composition. In the polymerization step, the polymerizable monomer in the droplets obtained in the granulation step is polymerized. And when manufacturing the toner particle which concerns on this invention, it is preferable to contain low molecular weight resin in a polymerizable monomer composition.

  The toner is preferably a toner having toner particles having at least a core part and a shell part. The toner particles have a shell portion so as to cover the core portion. By adopting such a structure, it is possible to prevent poor charging and blocking due to leaching of the core part to the toner particle surface. Further, it is more preferable that a surface layer portion having a resin composition different from that of the shell portion is present on the surface of the shell portion. The presence of this surface layer portion can further improve environmental stability, durability, and blocking resistance.

  Preferred examples of the polymerizable monomer that can be used to produce toner particles include a vinyl-based polymerizable monomer. For example, styrene; α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, p Styrene derivatives such as -n-hexyl styrene, pn-octyl, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-phenyl styrene; methyl acrylate, Ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, n-amyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n- Acrylic polymerizable monomers such as nonyl acrylate, cyclohexyl acrylate, benzyl acrylate, dimethyl phosphate ethyl acrylate, diethyl phosphate ethyl acrylate, dibutyl phosphate ethyl acrylate, 2-benzoyloxyethyl acrylate; methyl methacrylate, ethyl methacrylate, n -Propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, tert-butyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, n-nonyl methacrylate, diethyl Phosphate ethyl methacrylate, dibutyl phosphate Methacrylic polymerizable monomers such as methyl methacrylate; methylene aliphatic monocarboxylic acid esters; vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, vinyl benzoate, vinyl formate; vinyl methyl ether; And vinyl ethers such as vinyl ethyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropyl ketone.

  In the case of toner particles having a core-shell structure, the shell portion can be composed of a vinyl polymer formed from these vinyl polymerizable monomers or an added vinyl polymer. Among these vinyl polymers, a styrene polymer, a styrene-acrylic copolymer, or a styrene-methacrylic copolymer is preferable from the viewpoint of efficiently covering the wax mainly forming the inside or the central portion.

  Wax is preferred as the material constituting the core of the core-shell structured toner particles. Usable wax components include paraffin wax, microcrystalline wax, petroleum wax such as petrolatum and derivatives thereof, montan wax and derivatives thereof, hydrocarbon wax and derivatives thereof according to the Fischer-Tropsch method, polyolefin waxes such as polyethylene and polypropylene, and the like. Derivatives thereof, natural waxes such as carnauba wax and candelilla wax, and derivatives thereof, which include oxides, block copolymers with vinyl monomers, and graft modified products. Furthermore, higher fatty alcohols, fatty acids such as stearic acid and palmitic acid, or compounds thereof, acid amide waxes, ester waxes, ketones, hydrogenated castor oil and derivatives thereof, plant waxes, animal waxes, silicone resins are also wax components Can be used as

  The toner particles can include a colorant. As the black colorant, carbon black or a magnetic material can be used. In addition, toner particles that are toned in various colors using the following yellow / magenta / cyan colorants are used.

  Examples of the yellow colorant include compounds typified by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Specifically, the following C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 73, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 128, 129, 138, 147, 150, 151, 154, 155, 168, 180, 185, 214.

  Examples of the magenta colorant include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specifically, the following C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 122, 146, 166, 169, 177, 184, 185, 202, 206, 220, 221, 238, 254, 269, C.I. I. And CI Pigment Bio Red 19.

  Examples of cyan colorants include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, and basic dye lake compounds. Specifically, C.I. I. Pigment blue 1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, 66.

  These colorants can be used alone or in combination and further in the form of a solid solution. The colorant is selected from the viewpoints of hue angle, saturation, brightness, light resistance, OHP transparency, and dispersibility in the toner. The amount of the colorant added is, for example, 1 to 20 parts by mass added to 100 parts by mass of the polymerizable monomer.

  Further, a magnetic toner can be obtained by containing a magnetic material in the toner particles. In this case, the magnetic material can also serve as a colorant. Magnetic materials include iron oxides such as magnetite, hematite and ferrite; metals such as iron, cobalt and nickel or aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, Examples include alloys with metals such as calcium, manganese, selenium, titanium, tungsten, vanadium, and mixtures thereof. As the magnetic material, a surface-modified magnetic material is preferable. When magnetic toner particles are prepared by a polymerization method, a magnetic material that has been subjected to a hydrophobic treatment with a surface modifier that is a substance that does not inhibit polymerization is preferred. Examples of such surface modifiers include silane coupling agents and titanium coupling agents. These magnetic materials preferably have a number average particle diameter of 2 μm or less, more preferably 0.1 μm or more and 0.5 μm or less.

  The amount of the magnetic material to be contained in the toner particles is 20 parts by mass or more and 200 parts by mass or less, particularly preferably 40 parts by mass with respect to 100 parts by mass of the binder resin. The amount is preferably 150 parts by mass or less.

<Average circularity>
The average circularity of the toner particles needs to be 0.960 or more. When the average circularity is less than 0.960, even if the cleaning property is good, the fine line reproducibility is lowered. The average circularity of the toner particles is preferably 0.970 or more because fine line reproducibility is further improved.

  The present invention is more effective when the true sphere content of the toner is 10% or more. The true sphere content rate is the ratio of the number of toner particles having a circularity of 0.99 or more to the total number of toner particles. The higher the true sphere content rate, the better the fine line reproducibility.

<Manufacture of toner particles by grinding method>
Here, a pulverization method will be described as a manufacturing method for manufacturing toner particles.

  First, in the raw material mixing step, a predetermined amount of a polyester resin, a colorant, other additives, and the like are mixed and mixed as materials constituting the toner particles. Examples of the mixing apparatus include a double-con mixer, a V-type mixer, a drum-type mixer, a super mixer, an FM mixer, a nauter mixer, and a mechano-hybrid (trade name, manufactured by Nihon Coke Kogyo Co., Ltd.).

  Next, the mixed material is melt-kneaded to disperse the colorant and the like in the polyester resin. In the melt-kneading step, a batch kneader such as a pressure kneader or a Banbury mixer, or a continuous kneader can be used. Due to the advantage of continuous production, single-screw or twin-screw extruders are the mainstream. For example, KTK type twin screw extruder (trade name, manufactured by Kobe Steel), TEM type twin screw extruder (trade name, manufactured by Toshiba Machine Co., Ltd.), PCM kneader (trade name, manufactured by Ikekai), twin screw extruder (Trade name, manufactured by Kay Sea Kay Co., Ltd.), co-kneader (trade name, manufactured by Buss Co., Ltd.), kneedex (trade name, manufactured by Nihon Coke Kogyo Co., Ltd.), and the like. Furthermore, the resin composition obtained by melt-kneading may be rolled with two rolls or the like and cooled with water or the like in the cooling step.

  Next, the cooled product of the resin composition is pulverized to a desired particle size in the pulverization step. In the pulverization step, coarse pulverization is performed by a pulverizer such as a crusher, a hammer mill, or a feather mill. Thereafter, for example, a kryptron system (trade name, manufactured by Kawasaki Heavy Industries, Ltd.), a super rotor (trade name, manufactured by Nissin Engineering Co., Ltd.), a turbo mill (trade name, manufactured by Freund Turbo Inc.) and an air jet system. Pulverize with a pulverizer.

  Thereafter, classification is performed using a classifier or a sieving machine as necessary to obtain toner particles. For example, inertial class elbow jet (trade name, manufactured by Nippon Steel Mining Co., Ltd.), centrifugal classification turbo plex (trade name, manufactured by Hosokawa Micron), TSP separator (trade name, manufactured by Hosokawa Micron), Faculty (trade name, Hosokawa Micron) can be used.

  Further, the toner particles can be made spherical after pulverization. For example, hybridization system (trade name, manufactured by Nara Machinery Co., Ltd.), mechano-fusion system (trade name, manufactured by Hosokawa Micron), faculty (trade name, manufactured by Hosokawa Micron), Meteorinbo MR Type (trade name, Nippon Pneumatic Co., Ltd.) Made).

<Fixing of fine particles to toner particles>
In order to externally add external additives (fine particles) to the toner particles, the following mixer can be used. That is, FM mixer, COMPOSI (trade name, manufactured by Nippon Coke Kogyo Co., Ltd.), super mixer (trade name, manufactured by Kawata Corp.), nobilta (trade name, manufactured by Hosokawa Micron Corp.), hybridizer (trade name, manufactured by Nara Machinery Co., Ltd.), etc. It is. Using such an apparatus, the fine particles can be fixed to the surface of the toner particles. Among these, Nobilta and COMPOSI are preferable for controlling the liberation rate of the external additive from the toner particles and for uniformly coating the external additive on the toner particles. Or the external addition apparatus shown in FIG. 3 is preferable.
COMPOSI has a higher number of blade rotations than a conventional FM mixer and is provided with a collision plate, which can enhance the adhesion of external additives. Nobilta is also a device that can enhance the adhesion of external additives.

FIG. 3 is a schematic view showing an example of an external addition device (surface modification device). The surface modification apparatus 100 has the following elements.
A cylindrical main body casing 110.
A charging unit 150 on the side surface of the main body casing 110 for charging toner particles and fine particles into the main body casing 110.
A dispersion rotor 120 is provided on the upper portion of the main body casing 110 and is a means for dispersing toner particles and fine particles.
A fixing rotor 130, which is a lower part of the main body casing 110 and is a means for fixing the fine particles on the surface of the toner particles by mechanically impacting the toner particles and the fine particles dispersed by the dispersion rotor 120.
A guide ring 140 in the middle between the dispersion rotor 120 and the fixed rotor 130. This is a cylindrical guide that guides the toner particles and fine particles dispersed by the dispersion rotor 120 to the fixed rotor 130, and guides the toner having fine particles fixed to the surface of the toner particles by the fixed rotor 130 to the dispersion rotor 120. Means.
A discharge unit 160 for discharging the toner, which is on the side surface of the main body casing 110 and has fine particles fixed to the surface of the toner particles, to the outside of the main body casing 110.

  This apparatus can repeat the dispersion of toner particles and fine particles by the dispersion rotor 120 and the fixation of fine particles to the surface of the toner particles by the fixing rotor 130 for a predetermined time. The dispersion rotor 120 is fixed to a drive shaft 172 driven by a dispersion rotor drive motor 171 and rotates clockwise as viewed from above the main body casing 110. The fixed rotor 130 is fixed to the drive shaft 174 driven by the fixed rotor drive motor 173 and rotates clockwise as viewed from above the main body casing 110.

  When this apparatus is used, it is easy to fix the external additive having a large particle diameter, which is difficult with the conventional external addition apparatus, and the adhesion state of the fine particles tends to be uniform, and as a result, the coefficient of variation of the number of the fine particles is small. It is easy to become and is preferable.

  In order to reduce the coefficient of variation of the number of particles present, it is preferable to perform a premixing step before external addition. Although it does not specifically limit as an apparatus for performing premixing, It is an FM mixer, a super mixer (a brand name, the Kawata make), etc. Among them, the FM mixer is preferable.

<Removal of coarse particles>
In the present invention, coarse particles may be removed after external addition. Coarse particles are particles having a size of about 100 μm, and examples of the removal method include a sieving method. Examples of the sieving device used for sieving coarse particles after external addition include the following. Ultrasonic (trade name, manufactured by Koei Sangyo Co., Ltd.); Resonator Sheave, Gyroshifter (trade name, manufactured by Tokuju Kogakusha Co., Ltd.); Vibrasonic System (trade name, manufactured by Dalton Co., Ltd.); Turboscreener (trade name, manufactured by Turboe Industries Co., Ltd.); Microshifter (trade name, manufactured by Hadano Sangyo Co., Ltd.).

<Two-component developer using magnetic carrier>
The toner according to the present invention can be used as a one-component developer, but can also be mixed with a magnetic carrier and used as a two-component developer.

  Examples of the magnetic carrier include iron powder with oxidized surface or non-oxidized iron powder; metal particles such as iron, lithium, calcium, magnesium, nickel, copper, zinc, cobalt, manganese, rare earth, and alloy particles thereof. Commonly known materials such as magnetic particles such as oxide particles; ferrite; and a magnetic material-dispersed resin carrier (so-called resin carrier) containing a magnetic material and a binder resin that holds the magnetic material in a dispersed state are used. it can.

  When the toner according to the present invention is mixed with a magnetic carrier and used as a two-component developer, the mixing ratio of the toner and the magnetic carrier is 2% by mass or more and 15% by mass or less as the toner concentration in the developer. Is preferred.

<Method for measuring number average particle diameter of fine particles>
The number average particle diameter (D1) of primary particles of the external additive (fine particles) is measured using a scanning electron microscope “S-4800” (trade name; manufactured by Hitachi, Ltd.). The surface of the toner to which the external additive is externally added is observed, and in the field of view enlarged up to 200,000 times, the major axis of 100 primary particles of the external additive is randomly measured to obtain the number average particle size. The observation magnification is appropriately adjusted according to the size of the external additive.

<Measurement method of free rate of fine particles>
160 g of sucrose (manufactured by Kishida Chemical) is added to 100 mL of ion-exchanged water, and dissolved with a hot water bath to prepare a sucrose concentrate. In a centrifuge tube, 31 g of the above sucrose concentrate and 10 mass of neutral detergent for cleaning a precision measuring instrument with pH 7 consisting of Contaminone N (trade name, nonionic surfactant, anionic surfactant, organic builder) A 6 mL aqueous solution (made by Wako Pure Chemical Industries, Ltd.) is added to prepare a dispersion. 1 g of toner is added to this dispersion and the mass of toner is loosened with a spatula or the like.

The centrifuge tube is shaken with a shaker (trade name: Universal Shaker AS-1N, manufactured by ASONE) at 350 spm for 20 minutes. After shaking, the dispersion is replaced with a glass tube for swing rotor (50 mL), and separated with a centrifuge (trade name: H-9R manufactured by Kokusan Co., Ltd.) under conditions of 3500 s ⁻¹ and 30 min. It is visually confirmed that the toner and the aqueous solution are sufficiently separated, and the toner separated in the uppermost layer is collected with a spatula or the like. The collected aqueous solution containing the toner is filtered with a vacuum filter and then dried with a dryer for 1 hour or more. The dried product is crushed with a spatula, and the amount of the external additive is measured with fluorescent X-rays (aluminum ring diameter: 10 mm). The liberation rate is calculated from the toner obtained at this stage (referred to as “toner after washing with water”) and the external additive amount of the initial toner.

  The measurement of the fluorescent X-ray of each element is in accordance with JIS K 0119-1969, and is specifically as follows.

  For the measurement, a wavelength dispersive X-ray fluorescence analyzer “Axios” (trade name, manufactured by PANalytical) and attached dedicated software “SuperQ ver. 4.0F” (product) for setting measurement conditions and analyzing measurement data Name, manufactured by PANalytical). Rh is used as the anode of the X-ray tube, the measurement atmosphere is vacuum, the measurement diameter (collimator mask diameter) is 10 mm, and the measurement time is 10 seconds. Further, when measuring a light element, it is detected by a proportional counter (PC), and when measuring a heavy element, it is detected by a scintillation counter (SC).

  As a measurement sample, about 1 g of toner is put in a dedicated aluminum ring for press and flattened, and 20 MPa using a tablet molding compressor “BRE-32” (trade name, manufactured by Maekawa Test Instruments Co., Ltd.). Then, the pellets pressed for 60 seconds and molded to a thickness of about 2 mm are used. Measurement samples are prepared for the washed toner and the initial toner, respectively.

  The measurement is performed under the above conditions, the element is identified based on the obtained X-ray peak position, and the concentration is calculated from the count rate (unit: cps) which is the number of X-ray photons per unit time.

As a method for quantifying SiO _{2 in} the toner, silica (SiO ₂ ) fine powder is added to 0.10 parts by mass with respect to 100 parts by mass of the toner particles, and sufficiently mixed using a coffee mill. Similarly, silica fine powder is mixed with toner particles so as to be 0.20 parts by mass and 0.50 parts by mass, respectively, and these are used as samples for a calibration curve.

For each sample, a pellet for a calibration curve was prepared as described above using a tablet molding compressor, and the diffraction angle (2θ) was observed at 109.08 ° when PET was used as a spectroscopic crystal. The counting rate (unit: cps) of Si-Kα rays is measured. Here, PET means pentaerythritol. At this time, the acceleration voltage and current value of the X-ray generator are 24 kV and 100 mA, respectively. A calibration curve of a linear function is obtained with the X-ray count rate obtained on the vertical axis and the added amount of SiO ₂ in each calibration curve sample on the horizontal axis.

Next, the toner to be analyzed is pelletized as described above using a tablet molding compressor, and the counting rate of the Si-Kα rays is measured. Then, the SiO ₂ content in the toner is determined from the above calibration curve.

  The reduction rate of the external additive amount of the toner after water washing is defined as the liberation rate of the external additive with respect to the initial external additive amount calculated by the above method.

<Measuring method of average circularity of toner particles>
The average circularity of the toner particles is measured by a flow type particle image analyzer “FPIA-3000” (trade name, manufactured by Sysmex Corporation) under the measurement and analysis conditions during the calibration operation.

  A specific measurement method is as follows. First, about 20 mL of ion-exchanged water from which impure solids and the like are previously removed is placed in a glass container. About 0.2 mL of a diluted solution obtained by diluting the above-mentioned Contaminone N with ion-exchanged water about 3 times by mass as a dispersant is added thereto. Further, about 0.02 g of a measurement sample (toner particles) is added, and dispersion treatment is performed for 2 minutes using an ultrasonic disperser to obtain a dispersion for measurement. In that case, it cools suitably so that the temperature of a dispersion liquid may become 10 to 40 degreeC. As the ultrasonic disperser, a desktop type ultrasonic cleaner disperser (for example, “VS-150” (trade name, manufactured by Vervo Creer)) having an oscillation frequency of 50 kHz and an electric output of 150 W is used. A predetermined amount of ion-exchanged water is placed in the water tank of the ultrasonic disperser, and about 2 mL of the contamination N is added to the water tank.

  For the measurement, the flow type particle image analyzer equipped with “UPlanApro” (trade name, magnification 10 ×, numerical aperture 0.40) as an objective lens is used, and the particle sheath “PSE-900A” (product) Name, manufactured by Sysmex Corporation). The dispersion prepared in accordance with the above procedure is introduced into the flow type particle image analyzer, and 3000 toner particles are measured in the HPF measurement mode and in the total count mode. Then, the binarization threshold at the time of particle analysis is set to 85%, the analysis particle diameter is limited to the circle equivalent diameter of 1.985 μm or more and less than 39.69 μm, and the average circularity of the toner particles is obtained.

  In measurement, automatic focus adjustment is performed using standard latex particles diluted with ion-exchanged water) before starting the measurement. Thereafter, it is preferable to perform focus adjustment every two hours from the start of measurement. As the standard latex particles, for example, “RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5200A” (trade name) manufactured by Duke Scientific is used.

  In the examples of the present application, a flow-type particle image analyzer that has been issued a calibration certificate issued by Sysmex Corporation, which has been calibrated by Sysmex Corporation, was used. Measurement was performed under the measurement and analysis conditions when the calibration certificate was received, except that the analysis particle size was limited to a circle equivalent diameter of 1.985 μm or more and less than 39.69 μm.

<Method for Measuring Weight Average Particle Size (D4) of Toner Particles>
The weight average particle diameter (D4) of the toner particles is measured using a precision particle size distribution measuring device and dedicated software. The measuring device is a precise particle size distribution measuring device “Coulter Counter Multisizer 3” (registered trademark, manufactured by Beckman Coulter, Inc.) using a pore electrical resistance method equipped with a 100 μm aperture tube. The dedicated software is attached dedicated software “Beckman Coulter Multisizer 3 Version 3.51” (manufactured by Beckman Coulter, Inc.) for setting measurement conditions and analyzing measurement data. Using these, measurement is performed with 25,000 effective measurement channels, the measurement data is analyzed, and D4 is calculated.

  The electrolytic aqueous solution used for the measurement is a solution prepared by dissolving special grade sodium chloride in ion-exchanged water to a concentration of about 1% by mass, for example, “ISOTON II” (trade name, manufactured by Beckman Coulter, Inc.) it can.

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

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

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

  The specific method for measuring D4 is as follows.

  (1) About 200 mL of the electrolytic solution is placed in a glass 250 mL round-bottom beaker dedicated to Multisizer 3 and set on a sample stand, and the stirrer rod is stirred counterclockwise at 24 rpm. Then, dirt and bubbles in the aperture tube are removed by the “aperture flush” function of the analysis software.

  (2) About 30 mL of the electrolytic aqueous solution is put into a glass 100 mL flat bottom beaker, and about 0.3 mL of a diluted solution obtained by diluting the above-mentioned “Contaminone N” with ion-exchanged water 3 times as a dispersant is added thereto. .

  (3) Put 3.3 L of ion-exchanged water into a water tank of an ultrasonic disperser “Ultrasonic Dispensing System Tetora 150” (trade name, manufactured by Nikka Bios Co., Ltd.), and add about 2 mL of the above-mentioned Contaminone N into this water tank. To do. In this ultrasonic dispersion recording, two oscillators with an oscillation frequency of 50 kHz are incorporated with the phase shifted by 180 degrees, and the electrical output is 120 W.

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

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

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

  (7) The measurement data is analyzed with the dedicated software attached to the apparatus, and the weight average particle diameter (D4) is calculated. The “average diameter” on the analysis / volume statistics (arithmetic average) screen when the graph / volume% is set with the dedicated software is the weight average particle diameter (D4).

<Method for quantifying fine particles in toner>
When measuring the content of fine particles in a toner in which multiple types of external additives (fine particles) are externally added to the toner particles, the external additives are removed from the toner particles, and further, multiple types of external additives are isolated.・ It needs to be collected.

Specific examples of the method include the following methods.
(1) Put 5 g of toner into a sample bottle and add 200 ml of methanol.
(2) Disperse the sample for 5 minutes with an ultrasonic cleaner to peel the external additive from the toner particles.
(3) Separating toner particles and external additives by suction filtration (using a 10 μm membrane filter).
(4) Perform the above (2) and (3) three times.

  By the above operation, the externally added external additive is separated from the toner particles. At this time, when a plurality of external additives are present, the recovered aqueous solution containing the external additives is centrifuged to separate and recover the external additives. Next, the content of inorganic fine particles can be obtained by removing the solvent, sufficiently drying with a vacuum dryer, and measuring the weight. Incidentally, since the present measurement method measures the content using the specific gravity difference of the external additive, the present measurement method can be used only when only one kind of inorganic fine particles is contained.

<Measurement method of half-value width of primary particle peak in particle size distribution chart of fine particle weight>
The full width at half maximum of the primary particle peak in the particle size distribution chart based on the weight of the fine particles is measured with a disk centrifugal particle size distribution measuring apparatus DC24000 (trade name, manufactured by CPS Instruments Inc.).

  First, the disk is rotated at 24000 rpm with Motor Control on CPS software (included with disk centrifugal particle size distribution measuring apparatus DC24000). Then, the following conditions are set from Procedure Definitions.

(1) Sample parameter
・ Maximum Diameter: 0.5μm
・ Minimum Diameter: 0.05μm
• Particle Density: 2.0-2.2 g / mL (silica density; enter the value for the sample used)
-Particle Refractive Index: 1.43
・ Particle Absorption: 0K
・ Non-Sphericity Factor: 1.1
(2) Calibration Standard Parameters
・ Peak Diameter: 0.226μm
・ Half Height Peak Width: 0.1 μm
・ Particle Density: 1.389 g / mL
・ Fluid Density: 1.059g / mL
-Fluid Refractive Index: 1.369
-Fluid Viscosity: 1.1 cps.

After setting the above conditions, CPS Instruments Inc. Using an auto gradient maker AG300 (trade name), a density gradient solution of 8 mass% sucrose aqueous solution and 24 mass% sucrose aqueous solution is prepared, and 15 mL is injected into the measurement container.
After the injection, in order to prevent evaporation of the density gradient solution, 1.0 mL of dodecane (manufactured by Kishida Chemical Co., Ltd.) is injected to form an oil film and wait for 30 minutes or more to stabilize the apparatus.
After waiting, calibration standard particles (weight-based center particle size: 0.226 μm) are injected into the measuring apparatus with a 0.1 mL syringe, and calibration is performed. Thereafter, the collected supernatant is poured into the apparatus, and the weight-based particle size distribution is measured.

0.5 mg of Triton-X100 (trade name, manufactured by Kishida Chemical Co., Ltd.) is added to 100 g of ion-exchanged water to prepare a dispersion medium. 20 mg of the sample fine particles are added to 10.0 g of the dispersion medium, and dispersed by an ultrasonic disperser.
The ultrasonic disperser incorporates two oscillators with an oscillation frequency of 50 kHz with a phase shifted by 180 degrees, and an ultrasonic disperser “Ultrasonic Dispensing System Tet 150” with an electrical output of 120 W (trade name, Nikkei Bios Bios). Company-made). About 3.3 L of ion-exchanged water is placed in the water tank of the ultrasonic disperser, and about 2 ml of Contaminone N is added to the water tank.

  The dispersion liquid in which the fine particles are dispersed is put into a beaker, set in a beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. And the height position of a beaker is adjusted so that the resonance state of the liquid level of the electrolyte solution in a beaker may become the maximum. Then, the ultrasonic dispersion process is continued for 300 seconds. In the ultrasonic dispersion, the temperature of the water tank is appropriately adjusted so as to be 10 ° C. or higher and 40 ° C. or lower.

  Thereafter, 0.1 mL of the supernatant in the beaker is collected. For collection, a CPS-made measuring device is used only before an all-plastic disposable syringe (Tokyo Glass Instrument Co., Ltd.) equipped with a syringe filter (diameter: 13 mm / pore diameter 0.45 μm) (Advantech Toyo Co., Ltd.). Use a syringe needle attached. The supernatant collected with a syringe is injected into a disk centrifugal particle size distribution measuring apparatus DC24000 (trade name, manufactured by CPS Instruments Inc.), and the particle size distribution based on the weight of the fine particles is measured. A weight-based particle size distribution chart obtained by measurement is obtained. The half width of the peak of the particle size distribution in this chart is the half width of the peak of the primary particles of the fine particles.

  Although the basic configuration and features of the present invention have been described above, the present invention will be specifically described below based on examples. However, this does not limit the embodiment of the present invention. The number of parts in the examples is part by mass.

<Fine particles>
Fine particles were prepared by a conventionally known method for sol-gel silica and deflagration silica, and surface treatment was performed with HMDS (hexamethyldisilazane). The organic-inorganic composite fine particles were produced according to the description in the examples of WO 2013/063291.
Table 1 shows the physical properties of the fine particles used.

<Inorganic fine particles (second external additive)>
As inorganic fine particles (second external additive), a silica fine powder having a number average particle diameter (D1) of primary particles of 10 nm and a BET specific surface area of 125 m ² / g is subjected to surface treatment with hexamethyldisilazane and silicone oil. What was done was used.

<Production Example 1 of Toner Particles>
In a four-necked vessel, 710 parts of ion-exchanged water and 850 parts of a 0.1 mol / L Na ₃ PO ₄ aqueous solution were added and stirred at 12,000 s ⁻¹ using a high-speed stirrer TK-homomixer. Held at 0C. To this, 68 parts of a 1.0 mol / L-CaCl ₂ aqueous solution was gradually added to prepare an aqueous dispersion medium containing a fine hardly water-soluble dispersion stabilizer Ca ₃ (PO ₄ ) ₂ .

The following materials were prepared.
Styrene 124 parts n-butyl acrylate 36 parts Copper phthalocyanine pigment (Pigment Blue 15: 3) 13 parts Styrene resin (1) 40 parts Polyester resin (1) 10 parts (terephthalic acid-propylene oxide modified bisphenol A (2 mol adduct) (molar ratio = 51: 50), acid value = 10 mg KOH / g, glass transition point = 70 ° C., Mw = 10500, Mw / Mn = 3.20)
Negative charge control agent (aluminum compound of 3,5-di-tert-butylsalicylic acid)
0.8 parts wax (Fischer-Tropsch wax, endothermic main peak temperature = 78 ° C.)
15 copies.

The above materials were stirred for 3 hours using an attritor, and each component was dispersed in the polymerizable monomer to prepare a monomer mixture. To this monomer mixture, 20.0 parts of 1,1,3,3-tetramethylbutylperoxy 2-ethylhexanoate (50% by mass of toluene solution) as a polymerization initiator was added, and a polymerizable monomer was added. A composition was prepared. The polymerizable monomer composition was put into the aqueous dispersion medium, and granulated for 5 minutes while maintaining the rotational speed of the stirrer at 10,000 s- ¹ . Thereafter, the high-speed stirrer was changed to a propeller stirrer, the internal temperature was raised to 70 ° C., and the reaction was allowed to proceed for 6 hours with slow stirring.

Next, the temperature in the container was raised to 80 ° C. and maintained for 4 hours, and then gradually cooled to 30 ° C. at a cooling rate of 1 ° C. per minute to obtain slurry 1. Dilute hydrochloric acid was added to the container containing the slurry 1 to remove the dispersion stabilizer. Further, filtration, washing and drying were performed to obtain polymer particles (toner particles 1) having a weight average particle diameter (D4) of 6.3 μm. The true density of the toner particles was 1.1 g / cm ³ . The average circularity of the toner particles was 0.980.

<Example of manufacturing magnetic carrier>
Magnetite fine particles (spherical, number average particle diameter 250 nm, magnetization strength 65 Am ² / kg, specific resistance 3.3 × 10 ⁵ Ω · cm at 500 V / cm) and silane coupling agent (3- (2-amino Ethylaminopropyl) trimethoxysilane) was prepared. Magnetite fine particles and a silane coupling agent (amount of 3.0% by mass with respect to the mass of the magnetite fine particles) were introduced into the container. Then, the magnetite fine particles were surface-treated in the container by mixing and stirring at a high speed at a temperature of 100 ° C. or higher.

The following materials were prepared.
-Phenol 10 mass parts-Formaldehyde solution (formaldehyde 37 mass% aqueous solution) 16 mass parts-The above-mentioned surface-treated magnetite fine particles 84 mass parts The above materials were introduced into a reaction kettle and mixed well at a temperature of 40 ° C.

  Thereafter, the mixture was heated to 85 ° C. at an average temperature increase rate of 3 ° C./min with stirring, and 4 parts by mass of 28% by mass aqueous ammonia and 25 parts by mass of water were added to the reaction kettle. It was held at a temperature of 85 ° C. and cured by polymerization reaction for 3 hours. The peripheral speed of the stirring blade at this time was 1.8 m / sec.

After the polymerization reaction, the mixture was cooled to a temperature of 30 ° C. and water was added. The precipitate obtained by removing the supernatant was washed with water and further air-dried. The obtained air-dried product was dried under reduced pressure (5 hPa or less) at a temperature of 60 ° C., and a specific resistance of 7.0 × 10 ⁷ Ω · cm at an average particle diameter of 35 μm and 500 V / cm in which a magnetic material was dispersed. A carrier core (a) having an apparent density of 1.9 g / cm ³ was obtained.

Next, 35 parts by mass of a methyl methacrylate macromer (average value n = 50) having a weight average molecular weight of 5,000 having an ethylenically unsaturated group at one end and 65 parts by mass of a cyclohexyl methacrylate monomer having an ester moiety with cyclohexyl as a unit. A department was prepared. These were added to a four-necked flask with a reflux condenser, thermometer, nitrogen suction tube, and a mixing stirrer. Further, 90 parts by mass of toluene, 110 parts by mass of methyl ethyl ketone, and 2.0 parts by mass of azobisisovaleronitrile were added. The obtained mixture was held at 70 ° C. for 10 hours under a nitrogen stream to obtain a graft copolymer solution (solid content: 33% by mass). The weight average molecular weight of this solution by gel permeation chromatography (GPC) was 56,000. Moreover, the glass transition point Tg was 94 degreeC. To 30 parts by mass of the obtained graft copolymer solution, 1 part by mass of carbon black fine particles (maximum peak particle size based on number distribution is 30 nm, specific resistance is 1.0 × 10 ⁻⁴ Ω · cm), and 200 parts by mass of toluene. Part was added. And it mixed well with the homogenizer and obtained the coating solution (resin solution).

  Next, the above coating solution was gradually added while stirring 2000 g of carrier core (a) while continuously applying shear stress. The solvent was volatilized while stirring at 70 ° C. under reduced pressure to coat the surface of the magnetic carrier core with resin. The magnetic carrier core coated with this resin was heat-treated with stirring at 100 ° C. for 2 hours. After cooling, the mixture was crushed and coarse particles were removed with a sieve having an opening of 76 μm to obtain a magnetic carrier as a magnetic dispersion-type coated carrier.

<Example 1>
The external additive described in Table 2 (3.0 parts of fine particles 1) was added to the obtained toner particles 1 (100 parts), and the condition was 4000 s ^{−1 with} an FM mixer (trade name, manufactured by Nippon Coke). For 1 minute. Thereafter, the toner 1 was obtained by performing an external addition treatment with COMPOSI (trade name, manufactured by Nippon Coke) under the condition of 6000 s ⁻¹ for 4 minutes. The formulation and various physical properties of Toner 1 are as described in Table 2.

  The magnetic carrier produced as described above and the toner 1 were mixed so that the toner concentration was 10% by mass to prepare a two-component developer. The following evaluation test was performed on the obtained two-component developer. The evaluation results are shown in Table 3.

<Evaluation test>
Evaluation was performed using a Canon full-color copier image RUNNER ADVANCE C5051 (trade name) as an image forming apparatus. This device is a device that has not been designed for cleaning using a conventional spherical toner.

<Toner cleaning property>
In a low-temperature and low-humidity environment (10 ° C./14% Rh), a durability test was performed in which 10,000 sheets of ruled line images with a printing ratio of 5% were continuously output, and the cleaning performance was evaluated at 1000, 5000, and 10,000 sheets. When a cleaning failure occurs, the surface of the charging roller or paper is soiled by vertical streak-like toner. With cleaning performance evaluation, the state was confirmed visually.
A: No cleaning failure observed on paper, no contamination of charging roller with toner.
B: No cleaning failure observed on paper, and contamination of charging roller with toner.
C: After 50 sheets or more are printed out, vertical streaks due to poor cleaning can be seen on the paper, but this is practical enough.
D: Longitudinal streaks due to poor cleaning can be seen on paper when printing out 49 sheets or less.

<Contamination of charging member>
In a low-temperature and low-humidity environment (10 ° C./14% Rh), an endurance test for continuously outputting 10,000 images with a printing ratio of 20% was performed. The charging roller contamination due to the external additive was visually confirmed at 1,000, 5,000 and 10,000 sheets, and a halftone image was output to evaluate the charging roller contamination.
A: There is no problem of contamination of the charging roller up to 10,000 sheets.
B: No charging roller contamination problem up to 5000 sheets.
C: No charging roller contamination problem up to 1000 sheets.
D: Image defect due to contamination of charging roller occurred on 1000 sheets.

<Image density stability>
In the same image output test as the charging member contamination evaluation, a single solid image was output each time, and the density of each image was measured. Among the obtained output images, the difference between the maximum and minimum image density was determined and shown based on the following evaluation criteria. The image density was measured with a color reflection densitometer (trade name: X-RITE 404, manufactured by X-Rite).
A: The image density difference is 0.1 or less.
B: The image density difference is larger than 0.1 and not larger than 0.3.
C: The image density difference is greater than 0.3 and less than or equal to 0.5.
D: Image density difference is larger than 0.5. Image streaks due to development sleeve streaks occur on the image.

<Thin wire reproducibility>
The fine line reproducibility was evaluated from the viewpoint of image quality. In the above image output, after outputting 10,000 images, an image in which a grid pattern with a line width of 3 pixels is printed on the entire surface of A4 paper (print area ratio 4%) is printed, and fine line reproducibility is evaluated according to the following evaluation criteria. . The line width of 3 pixels is theoretically 127 μm. The line width of the image was measured with a microscope VK-8500 (trade name, manufactured by Keyence). The line width is measured by selecting 5 points at random, and the average value of 3 points excluding the minimum and maximum values is d (μm).
L (μm) = | 127−d |
Defined.

L defines the difference between the theoretical line width of 127 μm and the line width d on the output image. Since d may be larger than 127 or smaller than 127, it is defined as the absolute value of the difference. Smaller L indicates better fine line reproducibility.
A: L is 0 μm or more and less than 5 μm.
B: L is 5 μm or more and less than 15 μm, and a slight variation in the width of the fine line is observed.
C: L is 15 μm or more and less than 30 μm, and thin lines and splattering are observed, but are practically tolerable.
D: L is 30 μm or more, and thin lines are broken or thickened in some places.

<Example 2>
A toner 2 was obtained in the same manner as in Example 1 except that the prescriptions and external addition conditions shown in Table 2 were used.
Various physical properties of the toner are as shown in Table 2.
Table 3 shows the results of evaluation performed in the same manner as in Example 1.

<Example 3>
A toner 3 was obtained in the same manner as in Example 1 except that the prescriptions and external addition conditions shown in Table 2 were used.
Here, the apparatus shown in FIG. 3 is used as the external additive apparatus, and therefore the liberation rate of the external additive can be reduced.
Various physical properties of the toner are as shown in Table 2.
Table 3 shows the results of evaluation performed in the same manner as in Example 1.

<Examples 4 and 5>
Toners 4 and 5 were obtained in the same manner as in Example 1 except that the formulation and external addition conditions shown in Table 2 were used.
Various physical properties of the toner are as shown in Table 2.
Table 3 shows the results of evaluation performed in the same manner as in Example 1.

<Example 6>
A toner 6 was obtained in the same manner as in Example 1 except that the prescriptions and external addition conditions shown in Table 2 were used.
Various physical properties of the toner are as shown in Table 2.
Table 3 shows the results of evaluation performed in the same manner as in Example 1.
Explosive silica with a wide particle size distribution is used as the fine particles, and the coefficient of variation of the number of fine particles present is somewhat high.

<Example 7>
A toner 7 was obtained in the same manner as in Example 1 except that the formulation and the external addition conditions shown in Table 2 were used.
Various physical properties of the toner are as shown in Table 2.
Table 3 shows the results of evaluation performed in the same manner as in Example 1.

<Example 8>
A toner 8 was obtained in the same manner as in Example 1 except that the prescriptions and external addition conditions shown in Table 2 were used.
Here, nobilta is used as the external additive device, and therefore the liberation rate of the external additive is slightly high.
Various physical properties of the toner are as shown in Table 2.
Table 3 shows the results of evaluation performed in the same manner as in Example 1.

<Examples 9 and 10>
Toners 9 and 10 were obtained in the same manner as in Example 1 except that the formulation and external addition conditions shown in Table 2 were used.
Various physical properties of the toner are as shown in Table 2.
Table 3 shows the results of evaluation performed in the same manner as in Example 1.

<Example 11>
A toner 11 was obtained in the same manner as in Example 1 except that the prescriptions and external addition conditions shown in Table 2 were used. Since the pre-external addition is not performed before the external addition, the coefficient of variation of the number of fine particles present is slightly high.
Various physical properties of the toner are as shown in Table 2.
Table 3 shows the results of evaluation performed in the same manner as in Example 1.

<Examples 12 and 13>
Toners 12 and 13 were obtained in the same manner as in Example 1 except that the prescriptions and external addition conditions shown in Table 2 were used.
Various physical properties of the toner are as shown in Table 2.
Table 3 shows the results of evaluation performed in the same manner as in Example 1.

<Comparative Examples 1 to 6>
Toners 14 to 19 were obtained in the same manner as in Example 1 except that the prescriptions and external addition conditions shown in Table 2 were used. Various physical properties of the toner are as shown in Table 2. In Comparative Example 6 (toner 19), the above-described inorganic fine particles (surface-treated silica fine powder) were added when the fine particles 1 were added to the toner particles.
Table 3 shows the results of evaluation performed in the same manner as in Example 1.

DESCRIPTION OF SYMBOLS 100 ... Surface modification apparatus, 110 ... Main body casing, 120 ... Dispersion rotor, 130 ... Adhering rotor, 140 ... Guide ring, 150 ... Input part, 160 ... Discharge part, 171 ... Drive motor for dispersion rotors, 172 ... For dispersion rotors Drive shaft, 173 ... Drive motor for fixed rotor, 174 ... Drive shaft for fixed rotor

Claims (4)

Toner having toner particles and fine particles on the surface of the toner particles,
i) The average circularity of the toner particles is 0.960 or more,
ii) The wall friction angle θ calculated from the following equation of the toner is 10 ° or more and 15 ° or less,
θ = τ / σ
(Σ represents a vertical load (kPa) when a disc-shaped disk is allowed to enter a toner powder layer formed by applying a vertical load of 9.0 kPa,
τ represents the shear stress obtained when a disk-shaped disk is penetrated into the toner powder layer and rotated at (π / 10) rad / min at (π / 36) rad, and the measurement is performed at σ = 3 kPa. . )
iii) A propeller blade rotating at a peripheral speed of 100 mm / s at the outermost edge is vertically entered into the toner powder layer formed by applying a load of 3 kPa, and measured from a position 100 mm from the bottom of the powder layer. The total energy Et, which is the sum of the rotational torque and the vertical load of the propeller blade, obtained when starting from the bottom to a position of 10 mm from the bottom is 300 mJ or more and 600 mJ or less,
iv) The fine particles contain fine particles A having a number average particle diameter (D1) of primary particles of 200 nm or more and 500 nm or less, and the fine particles A have a liberation rate from the toner particles of 10% by mass or more and 50% by mass. Is
Toner characterized by the above. The average value of the abundance of fine particles having a particle diameter of 200 nm or more and 500 nm or less in the four regions in the reflected electron image of the toner surface photographed using a scanning electron microscope is expressed as the fine particle abundance Er on one toner surface. When
The average value of Er is 5 area% or more and 40 area% or less,
In the four regions, in the reflected electron image of the toner, a string that gives the maximum length is a line segment A, and two straight lines that are parallel to the line segment A and 1.5 μm apart from the line segment A are a straight line B and a straight line. C, a straight line passing through the midpoint of the line segment A and orthogonal to the line segment A is a straight line D, and two straight lines parallel to the straight line D and separated from the straight line D by 1.5 μm are defined as a straight line E and a straight line F 2. The region according to claim 1, wherein the four regions are each formed by a line segment A and straight lines B, C, D, E, and F, each of which is a square having a side length of 1.5 μm. toner. When the total value of the number of fine particles having a particle diameter of 200 nm to 500 nm in the four regions is defined as the number of fine particles present on one toner surface, variation coefficient variation coefficient = (standard deviation of En / En Average value)
The toner according to claim 2, wherein the toner is 0.5 or less. 4. The content of the fine particles A is 0.5 parts by mass or more and 5.0 parts by mass or less with respect to 100 parts by mass of the toner particles. 5. Toner.

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