JP2013134260A - Electrostatic charge image developer, process cartridge, image forming apparatus, and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic charge image developer with which an image in which an image void is suppressed can be obtained even when the developer is left to stand in a low temperature and low humidity environment and then used for continuously forming an image with a high image density.SOLUTION: The electrostatic charge developer comprises a toner and a carrier, the toner including toner particles and an external additive having a volume average particle diameter of 70 nm or more and 200 nm or less and an average circularity of 0.5 or more and 0.9 or less. When the developer is measured with a powder rheometer under the conditions of 20 ml/min ventilation flow volume, 100 mm/sec top speed of a rotating blade and -5° approaching angle of the rotating blade, the developer shows 30 mJ or more and 70 mJ or less of a ventilation fluidity energy amount.

Description

  The present invention relates to an electrostatic charge image developer, a process cartridge, an image forming apparatus, and an image forming method.

For example, Patent Document 1 discloses that an electrostatic image developing toner is obtained by adhering or fixing a charge control agent to the surface of a powder composed of at least a resin and a pigment, and the powder is previously compacted. When the conical rotor is rotated and penetrated into the 20 mm powder layer at the penetration speed of 5 mm / min, the value of the torque is 0.1-2. In the case of 5 mNm and a space ratio of 0.54, an electrostatic charge image developing toner characterized by 0.1 to 3.8 mNm has been proposed.
Further, Patent Document 1 states that “a toner for developing an electrostatic image is used to enter a toner layer in a container in which a compacted toner layer is formed while rotating the conical rotor to be applied to the conical rotor. A method for evaluating the fluidity of toner from the measured values by measuring the torque and the load applied to the container, wherein the apex angle of the conical rotor is 20 to 150 °. Toner evaluation method "has also been proposed.

  Patent Document 2 states that “a developer for developing an electrostatic image in which an additive is adhered or fixed to the surface of a powder composed of at least a resin and a pigment, and the developer is placed in a container and has a depth of 20 mm. When the developer layer in a compact state is formed, and the conical rotor is rotated from the top of the conical shape at a penetration speed of 5 mm / min while rotating the conical rotor, the torque applied to the conical rotor is 1.0 mNm to The developer is placed in a container to form a compacted developer layer having a depth of 20 mm, and the cone rotor is rotated while rotating the conical rotor from the top of the cone at a penetration rate of 5 mm / min. There has been proposed a “developer having a load applied to the container of 0.2 N to 0.8 N when it enters the developer layer”.

JP 2004-271826 A Japanese Patent Laying-Open No. 2005-091880

  An object of the present invention is to provide an electrostatic latent image developer capable of obtaining an image in which image omission is suppressed even when images having a high image density are continuously formed after being left in a low temperature and low humidity environment. is there.

The above problem is solved by the following means. That is,
The invention according to claim 1
A toner comprising toner particles and an external additive having a volume average particle size of 70 nm to 200 nm and an average circularity of 0.5 to 0.9;
Career,
Have
An electrostatic charge image developer having an aeration fluidity energy of 30 mJ or more and 70 mJ or less when measured with a powder rheometer under conditions of an air flow rate of 20 ml / min, a rotating blade tip speed of 100 mm / sec, and a rotating blade approach angle of -5 °. .

The invention according to claim 2
The electrostatic charge image developer according to claim 1, wherein the external additive is sol-gel silica particles.

The invention according to claim 3
The toner further has an external additive composed of vapor phase silica particles having a volume average particle diameter of 10 nm to 50 nm,
The toner particles are toner particles having an average circularity of 0.945 or more and 0.997 or less and a volume average particle size of 3.5 μm or more and 6.3 μm or less;
The electrostatic image developer according to claim 1, wherein the carrier is a carrier having a weight of 0.15 × 10 ⁻¹³ g or more and 0.83 × 10 ⁻¹³ g or less per carrier particle.

The invention according to claim 4
An image carrier,
A developing unit that contains the electrostatic charge image developer according to any one of claims 1 to 3 and that develops an electrostatic latent image formed on the image carrier as a toner image by the electrostatic charge image developer. When,
Comprising at least
A process cartridge that is detachable from the image forming apparatus.

The invention according to claim 5
An image carrier,
Charging means for charging the image carrier;
Electrostatic latent image forming means for forming an electrostatic latent image on the charged image carrier;
A developing unit that contains the electrostatic charge image developer according to any one of claims 1 to 3 and that develops an electrostatic latent image formed on the image carrier as a toner image by the electrostatic charge image developer. When,
Transfer means for transferring the toner image to a transfer object;
An image forming apparatus comprising at least

The invention according to claim 6
A charging step for charging the image carrier;
An electrostatic latent image forming step of forming an electrostatic latent image on a charged image carrier;
A developing step of developing the electrostatic latent image formed on the image carrier as a toner image with the electrostatic charge image developer according to any one of claims 1 to 3,
A transfer step of transferring the toner image to a transfer target;
An image forming apparatus comprising at least

According to the first and third aspects of the invention, the electrostatic charge image developer having a toner containing an external additive having a volume average particle diameter of 70 nm to 200 nm and an average circularity of 0.5 to 0.9. However, compared to an electrostatic charge image developer whose aeration fluidity energy amount is outside the above range, image omission is suppressed even when images having a high image density are continuously formed after being left in a low temperature and low humidity environment. An electrostatic latent image developer capable of obtaining a stable image can be provided.
According to the second aspect of the present invention, the low temperature and low humidity can be achieved as compared with the case where the external additive having a volume average particle size of 70 nm to 200 nm and an average circularity of 0.5 to 0.9 is vapor phase silica particles. It is possible to provide an electrostatic latent image developer capable of obtaining an image in which image loss is suppressed even when images having a high image density are continuously formed after being left in the environment.

  According to the inventions according to claims 4, 5, and 6, the electrostatic charge image developer having a toner containing an external additive having a volume average particle size of 70 nm to 200 nm and an average circularity of 0.5 to 0.9. In comparison with the case where an electrostatic charge image developer whose aeration fluidity energy amount is outside the above range is applied, even if a high image density image is continuously formed after standing in a low temperature and low humidity environment, the image It is possible to provide a process cartridge, an image forming apparatus, and an image forming method capable of obtaining an image in which omission is suppressed.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. It is a schematic block diagram which shows an example of the image forming apparatus of other this embodiment. It is a figure for demonstrating the measuring method of the fluid energy amount with a powder rheometer. It is a figure which shows the relationship between the vertical load and energy gradient which were obtained with the powder rheometer. It is a schematic diagram for demonstrating the shape of the rotary blade used with a powder rheometer.

  Hereinafter, an embodiment which is an example of the present invention will be described in detail.

(Electrostatic image developer)
The electrostatic charge image developer according to the exemplary embodiment (hereinafter sometimes referred to as a developer) includes a toner and a carrier.
The toner includes toner particles and an external additive having a volume average particle diameter of 70 nm to 200 nm and an average circularity of 0.5 to 0.9.
The developer according to the present embodiment has an aeration fluid energy amount when measured by a powder rheometer under conditions of an aeration flow rate of 20 ml / min, a rotating blade tip speed of 100 mm / sec, and a rotating blade entry angle of -5 °. It is 30 mJ or more and 70 mJ or less.

Here, an external additive having a volume average particle diameter (70 nm or more and 200 nm or less) that is not easily separated from the toner particles while ensuring a function as an external additive (hereinafter referred to as a spacer function) has an average circularity of 0.5 or more and 0. .9 or less (hereinafter referred to as a “typical external additive”), the irregular external additive suppresses rolling on the surface of the toner particles, thereby suppressing uneven distribution of the toner particle surface in the concave portions. It is thought that it tends to remain in the part.
Since the irregular external additive remaining on the convex portions of the toner particles increases the number of contacts with the toner particles due to the irregular shape, the force is dispersed even when an impact is applied, so that it is difficult to be embedded in the toner particles. It is thought that it will function and be maintained.

On the other hand, when an image is formed after standing in a low-temperature and low-humidity environment (for example, 5 ° C., 10% RH environment), there is an interaction effect between toners, between carriers, and between toner and carrier under low-temperature and low humidity conditions. When the developer is small, the developer tends to float. When the developer floats, rubbing between the toner and the carrier hardly occurs, and frictional charging hardly occurs. In the case of using a modified external additive, because of the deformed shape, even if an impact is applied, the force is dispersed, so that the developer is more likely to float, and at the initial stage of stirring, the developer is not sufficiently stirred. As a result, the toner often reaches the development area while the toner is not sufficiently charged.
In particular, when images with a high image density (for example, images with an image density of 60% or more) are continuously formed, the amount of replenishment toner increases, so that the developer is not sufficiently stirred with the replenishment toner, resulting in replenishment. In many cases, the toner reaches the developing area while the toner is not sufficiently charged.

  As described above, when the developer is not sufficiently stirred, if the externally shaped external additive exhibits a spacer function and is maintained, frictional charging between the toner and the carrier is limited, and the toner particle surface has a convex surface. It is considered that the frictional charge between the externally shaped external additive and the carrier staying at the part is mainly, and the convex part of the toner particle is locally highly charged.

  The locally high-charged toner has a high electrostatic adhesion force to the photosensitive member at the locally high-charged portion, and is thus difficult to be transferred. This is considered to be likely to occur.

  For this reason, when images having a high image density are continuously formed after being left in a low-temperature and low-humidity environment, an image in which image loss has occurred is often obtained.

Therefore, in the developer according to the present embodiment, in a developer having toner including toner particles and an externally shaped external additive and a carrier, the air flow energy amount is 30 mJ or more and 70 mJ or less (preferably 40 mJ or more and 60 mJ or less, More desirably, it is 40 mJ or more and 55 mJ or less.
As a result, with the developer according to the present exemplary embodiment, an image in which image omission is suppressed can be obtained even when images having a high image density are continuously formed after being left in a low temperature and low humidity environment.

Further, in the developer according to the present embodiment, the amount of air flow energy is within the above range, the air flow rate is 0 ml / min, the tip speed of the rotor blade is 100 mm / sec, and the approach angle of the rotor blade is -5 °. The basic fluid energy when measured by a powder rheometer is preferably 110 mJ or more and 190 mJ or less (preferably 120 mJ or more and 180 mJ or less, more preferably 130 mJ or more and 170 mJ or less).
By setting the basic fluidity energy amount within the above range, when images are continuously formed at a high image density after being left in a low-temperature and low-humidity environment, an image with image loss suppressed even immediately after the start of image formation. can get.

  These reasons are not clear, but are considered to be due to the following reasons.

First, the fluid energy amount will be described.
When measuring the fluidity of particles, since it is affected by more factors than when measuring the fluidity of liquids, solids, or gases, the parameters conventionally used, such as particle size and surface roughness, It is difficult to specify the exact fluidity of the particles. In addition, even if a factor to be measured (for example, particle size) is determined to specify fluidity, the factor actually has little effect on fluidity or only in combination with other factors. The significance of measuring the factor may arise, and even determining the measurement factor is difficult.

  Furthermore, the fluidity of the powder varies significantly depending on external environmental factors. For example, in the case of a liquid, even if the measurement environment changes, the fluctuation range of the fluidity is not so large, but the fluidity of the particles is greatly influenced by external environmental factors such as humidity and the state of the flowing gas. fluctuate. It is not clear which measurement factors are affected by these external environmental factors, so even if measured under strict measurement conditions, the reproducibility of the measured values obtained is actually poor. is there.

  In addition, fluidity when a developer (or toner) is filled in a developing device is known using an angle of repose or bulk density as an index. These physical property values are related to the fluidity of the developer. On the other hand, it is indirect, and it is difficult to quantify and manage the fluidity of the developer.

  However, since the powder rheometer can measure the amount of fluid energy applied from the developer (or toner) to the rotor blade of the measuring machine, it can be obtained as a sum of the factors attributable to fluidity. Therefore, the powder rheometer determines the items to be measured for the toner obtained by adjusting the physical property value and particle size distribution of the surface and the developer using the toner, as in the past, and the optimum physical properties for each item. Fluidity is measured directly without finding and measuring the value.

  As a result, the fluidity of the developer (or toner) used for developing the electrostatic image can be objectively determined only by confirming whether it falls within the above numerical range with a powder rheometer. Such management of the developer (or toner) is extremely suitable for practical use as compared with the conventional method of managing with the indirect value in order to ensure the fluidity of the intended developer (or toner). It is. Moreover, it is easy to make measurement conditions constant, and the reproducibility of measured values is high.

  That is, the method of specifying the fluidity with the value obtained by the powder rheometer is simple, accurate, and highly reliable as compared with the conventional method.

Next, a method for measuring fluidity using a powder rheometer will be described.
The powder rheometer is a fluidity measuring device that directly determines fluidity by simultaneously measuring rotational torque and vertical load obtained by rotating a rotating blade spirally in packed particles. By measuring both rotational torque and vertical load, fluidity including the characteristics of the powder itself and the influence of the external environment is detected with high sensitivity. In addition, since the measurement is performed with the particle filling state kept constant, data with good reproducibility can be obtained.

  Measurement is performed using FT4 manufactured by freeman technology as a powder rheometer. In order to eliminate the influence of temperature and humidity before the measurement, a developer (or toner) is used that has been left at a temperature of 25 ° C. and a humidity of 25% RH for 8 hours or more.

  First, the developer (or toner) is placed in a split container having an inner diameter of 25 mm (a cylinder having a height of 22 mm is placed on a 25 mL container having a height of 61 mm so that it can be separated vertically) with an amount exceeding 61 mm in height. Fill with developer (or toner).

  After the developer (or toner) is filled, an operation of homogenizing the sample is performed by gently stirring the filled developer (or toner). This operation will be called conditioning in the following.

  In conditioning, gently remove the excess air and partial stress by gently agitating the rotor blades in a rotating direction that does not receive resistance from the toner so as not to stress the developer (or toner) in the filled state. , Make the sample homogeneous. The specific conditioning conditions are that the inside of the container is stirred from a height of 70 mm to 2 mm from the bottom surface at an entry angle of 5 ° and a tip speed of a rotary blade of 40 mm / sec.

  At this time, the propeller-type rotor blades move downward simultaneously with the rotation, so that the tip draws a spiral, and the angle of the spiral path drawn by the propeller tip at this time is called the entry angle.

  After repeating the conditioning operation four times, the upper end of the split container is gently moved, and the developer (or toner) inside the vessel is worn at a position of 61 mm in height to obtain a toner that fills the 25 mL container. The conditioning operation is performed because it is important to always obtain a powder having a constant volume in order to obtain the fluid energy amount stably.

  Furthermore, after performing the conditioning operation once, the rotational torque when rotating at a tip speed of 100 mm / sec of the rotor blade while moving in the container from a height of 55 mm to 2 mm from the bottom at an approach angle of -5 ° Measure the vertical load. The direction of rotation of the propeller at this time is the reverse direction to the conditioning (clockwise as viewed from above).

3A and 3B show the relationship between the rotational torque or the vertical load with respect to the height H from the bottom surface. FIG. 4 shows an energy gradient (mJ / mm) with respect to the height H obtained from the rotational torque and the vertical load. The area (shaded portion in FIG. 4) obtained by integrating the energy gradient in FIG. 4 is the fluid energy amount (mJ). The flow energy amount is obtained by integrating the section from 2 mm to 55 mm in height from the bottom.
Moreover, in order to reduce the influence by an error, let the average value obtained by performing this conditioning and energy measurement operation cycle 5 times be a fluid energy amount (mJ).

  The rotor blade has a diameter of 23.5 mm of a two-blade propeller type shown in FIG. 5 manufactured by freeman technology.

  Then, when measuring the rotational torque and vertical load of the rotor blade, the fluid energy amount measured while flowing air at the target aeration flow rate (ml / min) from the bottom of the container is the “aeration fluid energy amount”. The amount of fluidity energy measured at an aeration flow rate of 0 ml / min without being vented from the bottom of the container is the “basic fluidity energy amount”. In the FT4 manufactured by freeman technology, the inflow state of the air flow rate is controlled.

Based on the above description, the developer having an aeration fluidity energy amount of 30 mJ or more and 70 mJ or less is a developer that defines a fluidity energy amount at a low aeration rate such as an aeration rate of 20 ml / min, This means a developer in which the triboelectric charging property between the toner and the carrier is ensured even in the initial stage of stirring.
In other words, a developer with such an airflow fluid energy amount suppresses the phenomenon that the developer floats even under low temperature and low humidity where the influence of interaction between toners, between carriers, and between toner and carrier is reduced. Therefore, it is considered that uniform frictional charging between the toner and the carrier is ensured even at the beginning of stirring of the developer.
In addition, even when a high image density image (for example, an image density of 60% or more) is continuously formed and a large amount of replenishment toner is replenished, the phenomenon that the developer or replenishment toner floats due to the inflow of air is suppressed. Thus, it is considered that the triboelectric charging property between the toner and the carrier is ensured.

If the rubbing time between the toner and the carrier is short to some extent, the frictional charging between the toner and the carrier is mainly due to the frictional charging between the external additive and the carrier that remains on the convex part of the toner particle surface, and the convex part of the toner particle is locally localized. Is considered to be highly charged. On the other hand, when the rubbing time between the toner and the carrier becomes longer, the triboelectric charge between the toner and the carrier is not only the triboelectric charge with the irregular external additive remaining on the convex portion of the toner particle surface, but the entire toner surface and the carrier. And occurs.
That is, it is considered that local charging of the toner particles is suppressed and the toner surface is easily charged over the entire surface.
For this reason, even after being left in a low-temperature and low-humidity environment (for example, in an environment of 5 ° C. and 10% RH) or even if a large amount of replenished toner is replenished, the toner can be charged without variation in a certain amount of time by stirring. It is thought to be realized.

  From the above, it is considered that the developer according to the present embodiment can obtain an image in which image omission is suppressed even when images having a high image density are continuously formed after being left in a low temperature and low humidity environment.

On the other hand, the developer having a basic fluid energy amount of 110 mJ or more and 190 mJ or less is a developer having a fluid energy amount when aeration is performed without aeration such as an aeration amount of 0 ml / min, and the flow is stopped. It means a developer that ensures high fluidity even immediately after the flow starts.
In other words, the developer having such basic fluidity energy amount can suppress the phenomenon that the developer floats due to the inflow of air with the flow even immediately after the start of stirring, and the rubbing time between the toner and the carrier is long. It is considered to be.
In addition, even after a large amount of replenishment toner is replenished, the phenomenon that the developer or replenishment toner floats due to the inflow of air is suppressed, and the replenishment toner is easily mixed (dispersed) by stirring. It is considered that the rubbing time between the toner (including the toner) and the carrier becomes longer.

  For this reason, in the developer according to the present embodiment, when the basic fluidity energy amount is in the above range, immediately after image formation is started in a case where images having a high image density are continuously formed after being left in a low temperature and low humidity environment. It is considered that an image in which image omission is suppressed is obtained even immediately after the start of development.

In the developer according to the exemplary embodiment, the externally shaped external additive is particularly preferably sol-gel silica particles.
The sol-gel silica particles are silica particles obtained by the sol-gel method among the wet methods, but have higher charge exchange properties than silica particles obtained by other production methods.
Therefore, when the carrier comes into contact with the toner and triboelectric charging occurs, the external additive exhibits a spacer function, thereby facilitating charging of the toner particles and suppressing local charging of the toner particles. In a short period, it is considered that the whole is easily charged.
As a result, in the case of continuously forming an image with a high image density after being left in a low-temperature and low-humidity environment, an image in which image omission is suppressed can be easily obtained even immediately after the start of image formation (immediately after the start of development). It is done.

Hereinafter, the developer will be described in detail.
The developer is a two-component developer containing toner and a carrier.
The toner includes toner particles and an external additive having a volume average particle diameter of 70 nm to 200 nm and an average circularity of 0.5 to 0.9.

  The mixing ratio (mass ratio) of toner and carrier in the two-component developer is preferably in the range of toner: carrier = 1: 100 to 30: 100, more preferably in the range of 3: 100 to 20: 100. desirable.

  The developer satisfies the aeration fluidity energy amount, preferably the basic fluidity energy amount. To adjust the amount of aeration fluid energy and the basic fluid energy in the developer, for example, toner particle shape, toner particle size, toner particle size distribution, type of external additive, particle size of external additive The adjustment is performed by adjusting the additive amount of the external additive, the type of carrier, the particle size of the toner, the particle size distribution of the carrier, and the like.

Specific examples of the constitution in which the developer satisfies the above-described aeration fluid energy amount, desirably the basic fluid energy amount, include the following combinations of toner and carrier.
Toner: Toner particles having an average circularity of 0.945 to 0.997, a volume average particle size of 3.5 μm to 6.3 μm, and a volume average particle size of 70 nm to 200 nm, and an average circularity of 0.5 to 0 Toner carrier having an external additive of 0.9 or less and an external additive composed of vapor phase silica particles having a volume average particle diameter of 10 nm to 50 nm (hereinafter referred to as other external additive): Carrier of 0.15 × 10 ⁻¹³ g or more and 0.83 × 10 ⁻¹³ g or less per carrier particle

  Hereinafter, each suitable element for the developer to satisfy the above-described aeration fluid energy amount, desirably the above basic fluid energy amount will be described.

First, toner particles will be described.
The average circularity of the toner particles is preferably 0.945 or more and 0.997 or less, but is preferably 0.955 or more and 0.980 or less.
Here, the average circularity of the toner particles is obtained by (equivalent circumference of circle) / (perimeter) [(perimeter of a circle having the same projection area as the particle image) / (perimeter of the projected particle image)]. A flow-type particle image analyzer (for example, Sysmex Corporation) takes a particle image as a still image by sucking and collecting the toner to be measured, forming a flat flow, and instantly flashing light, and analyzing the particle image. Obtained by FPIA-2100). The number of samplings when obtaining the average circularity is 3500.

The volume average particle size of the toner particles is preferably 3.5 μm or more and 6.3 μm or less, preferably 3.0 μm or more and 5.0 μm or less, more preferably 3.5 μm or more and 4.5 μm or less.
Here, the volume average particle diameter of each toner is a value measured as the volume average particle diameter of toner particles using a Multisizer II (manufactured by Beckman-Coulter) measuring device. As the electrolytic solution, ISOTON-II (manufactured by Beckman Coulter, Inc.) is used.

As a particle size distribution characteristic of the toner particles, a volume average particle size distribution index (GSDv) is preferably 1.25 or less, and preferably 1.22 or less.
The smaller the volume average particle size distribution index (GSDv) of the toner particles, the more uniform the particle size. By adjusting the particle size distribution characteristic, the amount of fluid energy in the powder rheometer can be easily controlled.

Here, the volume average particle diameter and the particle size distribution of the toner particles are measured as follows.
First, Coulter Multisizer II (manufactured by Coulter, Inc.) is used as a measuring device for particle size distribution (volume particle size distribution, number particle size distribution). As the electrolytic solution, 1% NaCl aqueous solution is prepared using first grade sodium chloride. For example, ISOTON-II (manufactured by Coulter Scientific Japan) is used. As a measuring method, 0.1 ml or more and 5 ml or less of a surfactant (desirably, alkylbenzene sulfonate) is added as a dispersant in 100 ml or more and 150 ml or less of an electrolytic aqueous solution, and further 2 mg or more and 20 mg or less of a measurement sample is added. The electrolyte in which the sample is suspended is subjected to a dispersion treatment for 1 minute or more and 3 minutes or less with an ultrasonic disperser, and the volume or number of toner (toner particles) is measured for each channel using a 100 μm aperture as an aperture by a measuring device. The volume particle size distribution or number particle size distribution of the toner is calculated. The above measurement is performed after the toner is dispersed in an electrolyte aqueous solution (isoton aqueous solution) and dispersed by ultrasonic waves for 30 seconds or more.

Then, a cumulative distribution is drawn from the small diameter side to the particle size range (channel) divided on the basis of the measured particle size distribution, and the particle diameter that becomes 16% is defined as the volume particle diameter D _16v , Number average particle size D _16P , particle size to be accumulated 50% is volume average particle size D _50v , number average particle size D _50P , particle size to be accumulated particle size 84% is volume particle size D _84v , number particle size D _84P It is defined as Then, the volume average particle size corresponds to the volume average particle diameter D _50.
Further, the volume average particle size distribution index (GSDv) is calculated as ( _D84v / _D16V ) ^1/2 .

  Note that the channels are 2.00 μm to 2.52 μm; 2.52 μm to 3.17 μm; 3.17 μm to 4.00 μm; 4.00 μm to 5.04 μm; 5.04 μm to 6.35 μm 6.35 μm or more and 8.00 μm or less; 8.00 μm or more and 10.08 μm or less; 10.08 μm or more and 12.70 μm or less; 12.70 μm or more and 16.00 μm or less; 16.00 μm or more and 20.20 μm or less; 13 channels of 25.40 μm or less; 25.40 μm or more and 32.00 μm or less; 32.00 μm or more and 40.30 μm or less are used.

  On the other hand, when the particle diameter to be measured was less than 2 μm, the measurement was performed using a Microtrac (manufactured by Nikkiso Co., Ltd., Microtrac UPA9340). As a measurement method, a sample in a dispersion is adjusted to have a solid content of about 2 g, and ion exchange water is added thereto to make about 40 ml. This is put into the cell until an appropriate concentration is reached, waits for about 2 minutes, and is measured when the concentration in the cell becomes almost stable. The obtained volume average particle diameter for each channel was accumulated from the smaller volume average particle diameter, and the volume average particle diameter was determined to be 50%.

  The toner particles may have a single layer structure or a structure (so-called core / shell structure) constituted by a core part and a coating layer covering the core part.

The configuration of the toner particles will be described.
The toner particles include, for example, a binder resin and, if necessary, other additives such as a colorant and a release agent.

  The binder resin is not particularly limited. For example, styrenes such as styrene, parachlorostyrene, and α-methylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, acrylic Esters having vinyl groups such as lauryl acid, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate; vinyl nitriles such as acrylonitrile and methacrylonitrile Vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone; single quantities of polyolefins such as ethylene, propylene and butadiene Homopolymer consisting of, or copolymers obtained by combining two or more of these, more mixtures thereof. In addition, epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, etc., non-vinyl condensation resins, or a mixture of these with the vinyl resin, or vinyl monomers in the presence of these resins Examples thereof include a graft polymer obtained by polymerization.

Styrene resin, (meth) acrylic resin, and styrene- (meth) acrylic copolymer resin are obtained by known methods, for example, by combining styrene monomers and (meth) acrylic acid monomers alone or in appropriate combination. It is done. “(Meth) acryl” is an expression including both “acryl” and “methacryl”.
The polyester resin can be obtained by selecting and combining suitable ones from a polyvalent carboxylic acid and a polyhydric alcohol and synthesizing them using a conventionally known method such as a transesterification method or a polycondensation method.

  When using a styrene resin, a (meth) acrylic resin or a copolymer resin thereof as a binder resin, the weight average molecular weight Mw is 20,000 or more and 100,000 or less, and the number average molecular weight Mn is 2,000 or more and 30,000 or less. It is desirable to use the thing of the range. On the other hand, when a polyester resin is used as the binder resin, a resin having a weight average molecular weight Mw of 5,000 or more and 40,000 or less and a number average molecular weight Mn of 2,000 or more and 10,000 or less may be used. desirable.

Here, as the binder resin, an amorphous resin and a crystalline resin may be used in combination.
The crystalline resin is preferably used in the range of 5% by mass to 30% by mass among the components constituting the toner particles. The amorphous resin is preferably used in the range of 50% by mass to 90% by mass among the components constituting the toner particles.

The “crystalline resin” refers to a resin having a clear endothermic peak, not a stepwise change in endothermic amount in differential scanning calorimetry (DSC). Specifically, it means that the half-value width of the endothermic peak when measured at a heating rate of 10 ° C./min is within 6 ° C.
On the other hand, a resin having a half-value width exceeding 6 ° C. or a resin having no clear endothermic peak means an amorphous resin, but the amorphous resin used in the present embodiment has a clear endothermic peak. It is better to use an unrecognized resin.

The crystalline resin is not particularly limited as long as it is a resin having crystallinity, and specific examples thereof include crystalline polyester resins and crystalline vinyl resins. However, crystalline polyester resins are preferred, especially aliphatic resins. The crystalline polyester resin is preferable.
The crystalline polyester resin and all other polyester resins are synthesized from, for example, a polyvalent carboxylic acid component and a polyhydric alcohol component.
In addition, a commercial item may be used as a polyester resin, and what was synthesize | combined may be used.

The colorant is selected from known colorants according to the intended toner color.
As the colorant, a surface-treated colorant may be used as necessary, or it may be used in combination with a dispersant. A plurality of colorants may be used in combination. As content of a coloring agent, the range of 1 to 30 mass parts is desirable with respect to 100 mass parts of binder resin.

  Examples of mold release agents include hydrocarbon waxes; natural waxes such as carnauba wax, rice wax, and candelilla wax; synthetic or mineral / petroleum waxes such as montan wax; ester types such as fatty acid esters and montanic acid esters. Wax; and the like, but is not limited thereto.

  The content of the release agent is preferably 1 part by mass or more and 15 parts by mass or less, more preferably 2 parts by mass or more and 12 parts by mass or less, and more preferably 3 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the binder resin. Even more desirable.

  Examples of other internal additives include magnetic materials, charge control agents, inorganic powders, and the like.

Next, the external profile additive will be described.
The irregular external additive is an external additive having a volume average particle size of 70 nm to 200 nm and an average circularity of 0.5 to 0.9.

The volume average particle diameter of the externally shaped additive is from 70 nm to 200 nm, preferably from 100 nm to 190 nm, and more preferably from 120 nm to 170 nm.
By setting the volume average particle diameter of the irregular external additive to 70 nm or more, the embedding in the toner particles is suppressed, and the function (spacer function) as the irregular external additive is easily secured.
On the other hand, by setting the volume average particle diameter of the irregular external additive to 200 nm or less, release from the toner particles is suppressed and defects due to a mechanical load are easily suppressed.

  The volume average particle size of the externally shaped external additive is determined by multiplying 100 primary particles of the externally shaped external additive after externally adding (dispersing) the externally shaped external additive to the toner particles by a scanning electron microscope (SEM) apparatus at a magnification of 40000 times. The longest diameter and the shortest diameter of each particle are measured by image analysis of primary particles, and the equivalent sphere diameter is measured from this intermediate value. The 50% diameter (D50v) in the cumulative frequency of the obtained equivalent sphere diameter is defined as the average particle diameter (that is, the volume average particle diameter) of the irregular external additive.

The average circularity of the modified external additive is 0.5 or more and 0.9 or less, and preferably 0.5 or more and 0.8 or less.
By setting the average circularity of the irregular external additive to 0.5 or more, stress concentration is suppressed when a mechanical load is applied, and defects due to the mechanical load are suppressed.
On the other hand, when the average circularity of the irregular external additive is 0.9 or less, the shape becomes irregular.

The degree of circularity of the externally shaped external additive is determined by observing primary particles of the externally shaped external additive after externally adding the externally shaped external additive to the toner particles with an SEM apparatus and analyzing the image of the obtained primary particles. Is obtained as “100 / SF2”.
Circularity (100 / SF2) = 4π × (A / I ² )
[In the formula, I represents the perimeter of the primary particles of the silica particles on the image, and A represents the projected area of the primary particles of the external additive. SF2 represents a shape factor.
The average circularity of the irregular external additive is obtained as 50% circularity in the cumulative frequency of the equivalent circle diameter of 100 primary particles obtained by the image analysis.

Examples of externally shaped external additives include well-known materials such as inorganic particles and organic particles that satisfy the above characteristics. Examples of the inorganic particles include silica (for example, fumed silica, sol-gel silica), alumina, titania, zinc oxide, tin oxide, iron oxide, calcium carbonate, magnesium carbonate, tricalcium phosphate, cerium oxide, tin oxide. And all particles usually used as external additives on the toner surface, such as iron oxide.
Examples of the organic particles include all particles that are usually used as external additives on the toner surface, such as vinyl resins, polyester resins, silicone resins, and fluorine resins.
These externally shaped additives are preferably subjected to a hydrophobic treatment on the surface.

Among these externally shaped additives, the externally shaped external additive is preferably silica particles, particularly sol-gel silica particles.
The silica particles may be produced by, for example, a method of obtaining silica sol using water glass as a raw material or a so-called wet method in which particles are generated by a sol-gel method using a silicon compound represented by alkoxysilane as a raw material. From the viewpoint of obtaining irregularly shaped silica particles satisfying the characteristics, the silica particles may be obtained by the following silica particle production method (hereinafter referred to as the present silica particle production method).

Hereinafter, the manufacturing method of this silica particle is demonstrated.
The method for producing the silica particles comprises a step of preparing an alkali catalyst solution containing an alkali catalyst at a concentration of 0.6 mol / L or more and 0.85 mol / L or less in a solvent containing alcohol (hereinafter referred to as “alkali catalyst solution preparation”). In some cases, tetraalkoxysilane is supplied into the alkali catalyst solution, and 0.1 mol or more to 0.1 mol per 1 mol of the total supply amount of tetraalkoxysilane supplied per minute. And a step of supplying an alkali catalyst at 4 mol or less (hereinafter sometimes referred to as “particle generation step”).

That is, in the method for producing silica particles, in the presence of the alcohol containing the alkali catalyst at the above concentration, while supplying the raw material tetraalkoxysilane and the alkali catalyst as a catalyst separately in the above relationship, In this method, tetraalkoxysilane is reacted to generate silane particles.
In the present method for producing silica particles, the above-mentioned method yields irregularly shaped silica particles satisfying the above characteristics with less generation of coarse aggregates.
In particular, in this method for producing silica particles, rounded irregularly shaped silica particles having a curved surface are obtained, so that the surface obtained by the dry process has a sharp and sharp protrusion. Compared with the silica particles having a shape, the contact area with the toner particles is increased, and even the irregularly shaped silica particles are easily suppressed from being detached from the toner particles, or are easily suppressed from being damaged by a mechanical load.
Although this reason is not certain, it is thought to be due to the following reasons.

  First, when an alkali catalyst solution containing an alkali catalyst is prepared in a solvent containing alcohol, and tetraalkoxysilane and an alkali catalyst are respectively supplied to this solution, the tetraalkoxysilane supplied in the alkali catalyst solution reacts. Thus, nuclear particles are generated. At this time, if the alkali catalyst concentration in the alkali catalyst solution is in the above range, it is considered that core particles having a low degree of circularity are generated while suppressing the formation of coarse aggregates such as secondary aggregates. This is because the alkali catalyst is coordinated to the surface of the generated core particle in addition to the catalytic action, and contributes to the shape and dispersion stability of the core particle. If the amount is within the above range, the alkali catalyst Does not cover the surface of the core particles uniformly (that is, because the alkali catalyst is unevenly distributed and adheres to the surface of the core particles), while maintaining the dispersion stability of the core particles, the surface tension and chemical affinity of the core particles This is because it is considered that a partial deviation occurs in the nuclei and core particles with low circularity are generated.

  When the tetraalkoxysilane and the alkali catalyst are continuously supplied, the produced core particles grow by the reaction of the tetraalkoxysilane, and silane particles are obtained. Here, by supplying the tetraalkoxysilane and the alkali catalyst while maintaining the supply amount in the above relationship, the generation of coarse aggregates such as secondary aggregates is suppressed, and the nucleus having low circularity It is considered that the particles grow while maintaining the irregular shape, and as a result, silica particles with low circularity are generated. This is because the supply amount of the tetraalkoxysilane and the alkali catalyst is in the above relationship, so that the partial distribution of the tension and chemical affinity on the surface of the core particle is maintained while maintaining the dispersion of the core particle. Therefore, it is considered that particle growth of the core particles occurs while maintaining the deformity.

From the above, it is considered that in the method for producing silica particles, the generation of coarse aggregates is small, and irregularly shaped silica particles can be obtained.
Then, in the method for producing silica particles, the core particles grow while maintaining the irregularity, so that it is considered that rounded irregularly shaped silica particles having a curved surface are obtained.

Here, the supply amount of tetraalkoxysilane is considered to be related to the particle size distribution and circularity of the silica particles. By reducing the supply amount of the tetraalkoxysilane to 0.002 mol / (mol · min) or more and less than 0.0090 mol / (mol · min), the contact probability between the dropped tetraalkoxysilane and the core particles is reduced, It is considered that the tetraalkoxysilane is supplied to the core particles evenly before the reaction between the tetraalkoxysilanes occurs. Therefore, it is considered that the reaction between the tetraalkoxysilane and the core particles can be generated without any bias. As a result, it is considered that the dispersion of particle growth is suppressed and silica particles with a narrow distribution width can be produced.
The volume average particle diameter of the silica particles is considered to depend on the total supply amount of tetraalkoxysilane.

In addition, in this method for producing silica particles, it is considered that silica particles are produced by generating irregularly shaped core particles and growing the nucleus particles while maintaining the deformed shape. It is thought that irregularly shaped silica particles having high properties can be obtained.
Further, in the method for producing silica particles, it is considered that the generated irregularly shaped core particles are grown while maintaining the irregular shape, and silica particles are obtained. It is thought that it is obtained.

  Further, in this method for producing silica particles, tetraalkoxysilane and alkali catalyst are respectively supplied to the alkali catalyst solution to cause a reaction of tetraalkoxysilane, thereby generating particles. Compared with the case of producing irregular shaped silica particles by the sol-gel method, the total amount of alkali catalyst used is reduced, and as a result, it is possible to omit the step of removing the alkali catalyst. This is particularly advantageous when silica particles are applied to products that require high purity.

Next, the alkali catalyst solution preparation step will be described.
In the alkali catalyst solution preparation step, a solvent containing alcohol is prepared, and an alkali catalyst is added thereto to prepare an alkali catalyst solution.

The solvent containing alcohol may be a solvent of alcohol alone or, if necessary, ketones such as water, acetone, methyl ethyl ketone, methyl isobutyl ketone, cellosolves such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, cellosolve acetate, It may be a mixed solvent with other solvents such as ethers such as dioxane and tetrahydrofuran.
In the case of a mixed solvent, the amount of alcohol relative to the other solvent is preferably 80% by mass or more (desirably 90% by mass or more).
Examples of the alcohol include lower alcohols such as methanol and ethanol.

  On the other hand, the alkali catalyst is a catalyst for accelerating the reaction (hydrolysis reaction, condensation reaction) of tetraalkoxysilane, and examples thereof include basic catalysts such as ammonia, urea, monoamine, quaternary ammonium salts, Ammonia is particularly desirable.

The concentration (content) of the alkali catalyst is 0.6 mol / L or more and 0.85 mol / L, desirably 0.63 mol / L or more and 0.78 mol / L, more desirably 0.66 mol / L or more and 0. .75 mol / L.
If the concentration of the alkali catalyst is less than 0.6 mol / L, the dispersibility of the core particles in the growth process of the generated core particles becomes unstable, and coarse aggregates such as secondary aggregates are generated or gelled. The particle size distribution may deteriorate.
On the other hand, when the concentration of the alkali catalyst is higher than 0.85 mol / L, the stability of the generated core particles becomes excessive, and spherical core particles are generated, and irregularly shaped nuclei having an average circularity of 0.90 or less. Particles can be difficult to obtain.
In addition, the density | concentration of an alkali catalyst is a density | concentration with respect to an alcohol catalyst solution (an alkali catalyst + solvent containing alcohol).

The particle generation process will be described.
In the particle generation step, tetraalkoxysilane and an alkali catalyst are respectively supplied to an alkali catalyst solution, and the tetraalkoxysilane is reacted (hydrolysis reaction, condensation reaction) in the alkali catalyst solution to obtain silica particles. Is a step of generating.
In this particle generation process, after the core particles are generated by the reaction of tetraalkoxysilane at the initial stage of supply of tetraalkoxysilane (core particle generation stage), the core particles are grown (core particle growth stage), and then the silica particles are Generate.

  Examples of the tetraalkoxysilane supplied into the alkali catalyst solution include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, and the like. From the viewpoints of diameter, particle size distribution, etc., tetramethoxysilane and tetraethoxysilane are preferable.

The supply amount of tetraalkoxysilane is preferably 0.002 mol / (mol · min) or more and 0.0090 mol / (mol · min) or less with respect to the alcohol in the alkali catalyst solution.
This means that tetraalkoxysilane is supplied at a supply rate of 0.002 mol or more and 0.0090 mol or less per minute with respect to 1 mol of alcohol used in the step of preparing the alkali catalyst solution.

If the supply amount of tetraalkoxysilane is less than 0.002 mol / (mol · min), the contact probability between the dropped tetraalkoxysilane and the core particles is further lowered, but the total supply amount of tetraalkoxysilane is reduced. It takes a long time to finish dripping, and the production efficiency is poor.
If the supply amount of tetraalkoxysilane exceeds 0.0090 mol / (mol · min), it is considered that the reaction between the tetraalkoxysilanes occurs before the dropped tetraalkoxysilane reacts with the core particles. . For this reason, the uneven distribution of the tetraalkoxysilane supply to the core particles is promoted and variations in the formation of the core particles are brought about, so that the distribution width of the shape distribution is easily expanded.

  The supply amount of tetraalkoxysilane is preferably 0.002 mol / (mol · min) or more and 0.0045 mol / (mol · min) or less, and more preferably 0.002 mol / (mol · min) or more and 0.0035 mol / ( mol · min) or less.

  On the other hand, examples of the alkali catalyst supplied into the alkali catalyst solution include those exemplified above. The alkali catalyst to be supplied may be of the same type as the alkali catalyst previously contained in the alkali catalyst solution, or may be of a different type, but is preferably of the same type.

The supply amount of the alkali catalyst is 0.1 mol or more and 0.4 mol or less, preferably 0.14 mol or more and 0.35 mol or less, more preferably 0.1 mol or less with respect to 1 mol of the total supply amount of tetraalkoxysilane supplied per minute. Is 0.18 mol or more and 0.30 mol or less.
If the supply amount of the alkali catalyst is less than 0.1 mol, the dispersibility of the core particles in the growth process of the generated core particles becomes unstable, and coarse aggregates such as secondary aggregates are generated, The particle size distribution may deteriorate.
On the other hand, if the supply amount of the alkali catalyst is more than 0.4 mol, the stability of the generated core particles becomes excessive, and even if core particles with low circularity are generated in the core particle generation stage, In some cases, the core particles grow in a spherical shape, and silica particles with low circularity cannot be obtained.

  Here, in the particle generation step, tetraalkoxysilane and an alkali catalyst are supplied into the alkali catalyst solution, respectively, but this supply method may be a continuous supply method or intermittently. The method of supplying to

  In the particle generation step, the temperature in the alkaline catalyst solution (temperature at the time of supply) is, for example, preferably 5 ° C. or more and 50 ° C. or less, and desirably 15 ° C. or more and 40 ° C. or less.

  Silica particles are obtained through the above steps. In this state, the resulting silica particles are obtained in the form of a dispersion, but the solvent is removed and used as a silica particle powder.

Solvent removal methods for the silica particle dispersion include 1) a method of removing the solvent by filtration, centrifugation, distillation, etc., and then drying with a vacuum dryer, shelf dryer, etc. 2) a fluidized bed dryer, spray dryer A known method such as a method of directly drying the slurry by, for example, may be mentioned. The drying temperature is not particularly limited, but is desirably 200 ° C. or lower. When the temperature is higher than 200 ° C., bonding between primary particles and generation of coarse particles are likely to occur due to condensation of silanol groups remaining on the surface of the silica particles.
The dried silica particles are preferably crushed and sieved as necessary to remove coarse particles and aggregates. The crushing method is not particularly limited, and for example, the crushing method is performed by a dry pulverization apparatus such as a jet mill, a vibration mill, a ball mill, or a pin mill. The sieving method is performed by a known method such as a vibration sieve or a wind sieving machine.

Here, the silica particles obtained by the present method for producing silica particles are preferably subjected to a hydrophobic treatment on the surface of the silica particles with a hydrophobic treatment agent.
Examples of the hydrophobizing agent include known organosilicon compounds having an alkyl group (eg, methyl group, ethyl group, propyl group, butyl group). Specific examples include, for example, silazane compounds (eg, methyl trimethyl compound). Silane compounds such as methoxysilane, dimethyldimethoxysilane, trimethylchlorosilane, and trimethylmethoxysilane, hexamethyldisilazane, tetramethyldisilazane, and the like. The hydrophobizing agent may be used alone or in combination.

Among these hydrophobizing agents, organosilicon compounds having a trimethyl group such as trimethylmethoxysilane and hexamethyldisilazane are suitable.
The amount of the hydrophobizing agent used is not particularly limited, but in order to obtain a hydrophobizing effect, for example, 1% by mass to 100% by mass, preferably 5% by mass to 80% by mass with respect to the silica particles. It is as follows.

As a method for obtaining a hydrophobic silica particle dispersion subjected to a hydrophobizing treatment with a hydrophobizing agent, for example, a necessary amount of a hydrophobizing agent is added to the silica particle dispersion, and 30 to 80 ° C. with stirring. The method of hydrophobizing a silica particle by making it react in the temperature range of this, and obtaining the hydrophobic silica particle dispersion liquid is mentioned. When the reaction temperature is lower than 30 ° C., the hydrophobization reaction hardly proceeds, and when the reaction temperature exceeds 80 ° C., the gelation of the dispersion due to the self-condensation of the hydrophobizing agent or the aggregation of silica particles tends to occur. is there.
On the other hand, as a method of obtaining powdery hydrophobic silica particles, a method of obtaining hydrophobic silica particle powder by hydrophobizing in a silica particle dispersion and drying the silica particle dispersion, After obtaining a hydrophilic silica particle powder, a hydrophobic treatment agent is added and subjected to a hydrophobic treatment to obtain a hydrophobic silica particle powder, and the hydrophobic treatment is performed in a silica particle dispersion. Examples include a method of obtaining a powder of hydrophobic silica particles by drying and obtaining a powder of hydrophobic silica particles, and further adding a hydrophobizing agent to perform hydrophobic treatment.

  Here, as a method of hydrophobizing the silica particles of the powder, the hydrophilic silica particles of the powder are stirred in a processing tank such as a Henschel mixer or a fluidized bed, and a hydrophobizing agent is added thereto, and the processing tank A method of gasifying the hydrophobizing agent by heating the inside and reacting it with silanol groups on the surface of the silica particles of the powder is mentioned. Although processing temperature is not specifically limited, For example, 80 degreeC or more and 300 degrees C or less are good, Desirably 120 degreeC or more and 200 degrees C or less.

  The externally shaped external additive described above is preferably added in an amount of 0.5 parts by mass or more and 5.0 parts by mass or less, more preferably 0.7 parts by mass or more and 4.0 parts by mass with respect to 100 parts by mass of the toner particles. More preferably, it is 0.9 parts by mass or more and 3.5 parts by mass or less.

Next, other external additives will be described.
The second external additive is gas phase method silica particles having a volume average particle diameter of 10 nm to 50 nm.
The gas phase method silica particles are, for example, silica particles obtained by a flame hydrolysis method. Specifically, the vapor phase silica particles are silica particles obtained by burning silicon tetrachloride with hydrogen and oxygen, for example.
The vapor phase silica particles may be silica particles obtained by burning silanes (for example, methyltrichlorosilane and trichlorosilane) alone with hydrogen and oxygen instead of silicon tetrachloride, Silica particles obtained by burning a mixture of silicon tetrachloride and silanes with hydrogen and oxygen may be used.

The volume average particle size of other external additives (gas phase method silica particles) is from 10 nm to 50 nm, preferably from 15 nm to 50 nm, and more preferably from 20 nm to 40 nm.
When the volume average particle diameter of other external additives is larger than 50 nm, the toner tends to roll on the toner surface, and the basic fluidity energy value tends to fall below the desired range.
On the other hand, when the volume average particle diameter of the other external additives is smaller than 10 nm, it is easily embedded in the toner surface and the fluidity is hardly exhibited. For this reason, the basic fluidity energy value tends to deviate above the desired range.

  By setting the volume average particle size of the other external additive (gas phase method silica particles) within the above range, the aeration fluid energy amount, preferably the basic fluid energy amount is easily satisfied.

The volume average particle size of other external additives (gas phase method silica particles) is divided using the particle size distribution obtained by measurement with a laser diffraction particle size distribution analyzer (for example, LA-700, manufactured by Horiba, Ltd.). With respect to the particle size range (channel), the cumulative distribution is drawn from the small particle size side with respect to the volume, and the particle size that becomes 50% cumulative with respect to all external additives is determined as the volume average particle size D _50p .

  Other external additives (gas phase method silica particles) are preferably hydrophobized with a hydrophobizing agent.

  The other external additives described above are preferably added in an amount of 0.1 to 5 parts by weight, more preferably 0.5 to 3 parts by weight with respect to 100 parts by weight of the toner particles. More desirably, it is 1 part by mass or more and 2 parts by mass or less.

Next, a toner manufacturing method will be described.
The toner is obtained by externally adding an external additive to the toner particles after producing the toner particles.
The toner particles are preferably produced by wet granulation. Examples of the wet granulation method include known melt suspension methods, emulsion aggregation / unification methods, and dissolution suspension methods.
Examples of a method of externally adding an external additive to the obtained toner particles include a method of mixing with a known mixer such as a V-type blender, a Henschel mixer, and a Redige mixer.

Next, the carrier will be described.
As the carrier, the weight per carrier particle is small (specifically, 0.15 × 10 ⁻¹³ g or more and 0.83 × 10 ⁻¹³ g or less, preferably 0.19 × 10 ⁻¹³ g or more and ^0.005 g or less). 65 × 10 ⁻¹³ g or less).
Examples of the carrier having a small weight per carrier particle include a carrier having a small specific gravity. Specifically, for example, 1) a magnetic powder-dispersed carrier in which magnetic powder is dispersed and blended in a matrix resin, 2) A resin-impregnated carrier obtained by impregnating a porous magnetic powder with a resin.
Further, as the diameter is reduced, the weight per carrier particle becomes smaller.
The magnetic powder-dispersed carrier and resin-impregnated carrier use as a core a particle in which a magnetic powder is dispersed and blended in a matrix resin, or a particle in which a porous magnetic powder is impregnated with a resin. It may be a carrier coated with. Thereby, it is easy to obtain a carrier having a smooth surface.

Here, the weight per carrier particle is determined by (volume of one carrier × specific gravity). The volume of one carrier is obtained by 4/3 × π × (volume average particle diameter / 2) ³ . The method for measuring the specific gravity of the carrier particles is as follows.
The measurement was performed according to JIS-K-0061 5-2-1 using a Le Chatelier specific gravity bottle.
(1) Put about 250 ml of ethyl alcohol into a Le Chatelier specific gravity bottle and adjust so that the meniscus is at the position of the scale.
(2) The specific gravity bottle is immersed in a constant temperature water bath, and when the liquid temperature reaches 20.0 ± 0.2 ° C., the position of the meniscus is accurately read on the scale of the specific gravity bottle (accuracy 0.0025 ml).
(3) Weigh about 100 g of the sample.
(4) Put the weighed sample in a specific gravity bottle to remove bubbles.
(5) The specific gravity bottle is immersed in a thermostatic bath, and when the liquid temperature reaches 20.0 ± 0.2 ° C., the position of the meniscus is accurately read on the scale of the specific gravity bottle (accuracy 0.0025 ml).
(6) The true specific gravity is calculated by the following equations (3-1) and (3-2).
Formula (3-1): D = W / (L2-L1)
Formula (3-2): S = D / 0.9982
(Where D is the density of the sample (g / cm ³ , 20 ° C.), S is the specific gravity of the sample (20 ° C.), W is the apparent mass of the sample (g), and L1 is before the sample is placed in the specific gravity bottle. Meniscus reading (ml, 20 ° C.), L2 is the meniscus reading (ml, 20 ° C.) after the sample is placed in the density bottle, and 0.9982 is the density of water at 20 ° C. (g / cm ³ ). is there.
The specific gravity is controlled by adjusting the magnetic powder composition, the magnetic powder amount, and the resin coating layer amount.

  Examples of the magnetic powder include magnetic metals such as iron oxide, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite.

Examples of the coating resin that coats the core material, the matrix resin that disperses and blends the magnetic powder, and the resin that impregnates the porous magnetic powder include, for example, polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, and polyvinyl chloride. , Polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic acid copolymer, straight silicone resin containing an organosiloxane bond or a modified product thereof, fluorine resin, polyester, polycarbonate, phenol resin And epoxy resins.
The coating resin for coating the core material, the resin for dispersing and blending the magnetic powder, and the resin for impregnating the porous magnetic powder may contain other additives such as a conductive material.

  When the core material is coated with the coating resin, the coating amount of the coating resin on the core material is, for example, 0.5% by mass or more (desirably 0.7% by mass or more and 6% by mass or less) with respect to the mass of the entire carrier. More desirably, the content is 1.0% by mass or more and 5.0% by mass or less.

The coating amount of the core material with the coating resin is determined as follows.
In the case of a solvent-soluble coating resin, a precise amount of carrier is dissolved in a soluble solvent (for example, toluene), the magnetic powder is held by a magnet, and the solution in which the coating resin is dissolved is washed away. By repeating this several times, the magnetic powder from which the clothing resin has been removed remains. The coating amount is calculated by drying, measuring the mass of the magnetic powder, and dividing the difference by the carrier amount.
Specifically, 20.0 g of the carrier is measured, put into a beaker, 100 g of toluene is added, and the mixture is stirred with a stirring blade for 10 minutes. A magnet is applied to the bottom of the beaker, and toluene is allowed to flow so that the core material (magnetic powder) does not flow out. This is repeated 4 times, and the beaker after washing is dried. After drying, the amount of magnetic powder is measured, and the coating amount is calculated by the formula [(carrier amount−magnetic powder amount after washing) / carrier amount].
On the other hand, in the case of a solvent-insoluble coating resin, Rigaku's Thermo plus EVOII differential type differential thermobalance TG8120 is heated in a nitrogen atmosphere in the range of room temperature (25 ° C.) to 1000 ° C., and its mass is reduced. From this, the coating amount is calculated.

The volume average particle diameter of the carrier is preferably 10 μm or more and 100 μm or less, preferably 15 μm or more and 40 μm or less, more preferably 20 μm or more and 30 μm or less.
Here, the volume average particle diameter of each carrier is measured as a volume average particle diameter of carrier particles using a laser diffraction / scattering particle size distribution measuring device (LS Particle Size Analyzer (manufactured by Beckman Coulter)). As the electrolytic solution, ISOTON-II (manufactured by Beckman-Coulter) is used.

As the particle size distribution characteristic of the carrier, the volume average particle size distribution index (GSDv) is preferably 1.25 or less, and desirably 1.20 or less.

By adjusting the particle size distribution characteristics, the amount of fluid energy in the powder rheometer can be easily controlled.

(Image forming devices, etc.)
As shown in FIG. 1, the image forming apparatus 101 according to the present embodiment includes, for example, an electrophotographic photosensitive member 10 (an example of an image holding member) that rotates clockwise as indicated by an arrow A, and an electrophotographic photosensitive member. A charging device 20 (an example of a charging unit) that is provided above the body 10 and is opposed to the electrophotographic photoreceptor 10 and charges the surface of the electrophotographic photoreceptor 10, and the electrophotographic photoreceptor 10 charged by the charging device 20. An exposure device 30 (an example of an electrostatic latent image forming unit) that exposes the surface of the toner to form an electrostatic latent image, and a toner contained in the developer is attached to the electrostatic latent image formed by the exposure device 30. A developing device 40 (an example of a developing unit) that forms a toner image on the surface of the electrophotographic photosensitive member 10, and a transfer device that transfers the toner image on the electrophotographic photosensitive member 10 to a recording paper P (an example of a transfer target). 50 and the surface of the electrophotographic photoreceptor 10 And a cleaning device 70 (an example of a toner removing means) for cleaning.
The image forming apparatus 101 according to the present embodiment is provided with a fixing device 60 that fixes the toner image while conveying the recording paper P on which the toner image is formed.

  Details of main components in the image forming apparatus 101 according to the present embodiment will be described below.

-Electrophotographic photoreceptor-
Examples of the electrophotographic photoreceptor 10 include an inorganic photoreceptor in which a photosensitive layer provided on a conductive substrate is made of an inorganic material, and an organic photoreceptor in which a photosensitive layer is made of an organic material. Organic photoreceptors include a functionally separated photoreceptor in which a charge generation layer that generates charges by conductive exposure and a charge transport layer that transports charges are stacked on a conductive substrate, or a charge on a conductive substrate. And a photoconductor provided with a single-layer type photosensitive layer in which the same layer performs the function of generating a charge and the function of transporting charges. Examples of the inorganic photoreceptor include a photoreceptor in which a photosensitive layer made of amorphous silicon is provided on a conductive substrate.
The shape of the electrophotographic photoreceptor 10 is not limited to a cylindrical shape, and a known shape such as a sheet shape or a plate shape may be employed.

-Charging device-
Examples of the charging device 20 include a contact charger using a conductive charging roller, a charging brush, a charging film, a charging rubber blade, a charging tube, and the like.
Examples of the charging device 20 include a non-contact type roller charger and a known charger such as a scorotron charger using a corona discharge or a corotron charger.

-Exposure device-
Examples of the exposure apparatus 30 include optical system devices that expose the surface of the electrophotographic photoreceptor 10 with light such as semiconductor laser light, LED light, and liquid crystal shutter light imagewise. The wavelength of the light source is preferably within the spectral sensitivity region of the electrophotographic photoreceptor 10. The wavelength of the semiconductor laser is preferably near infrared having an oscillation wavelength of around 780 nm, for example. However, the present invention is not limited to this wavelength, and an oscillation wavelength laser in the 600 nm range or a laser having an oscillation wavelength of 400 nm to 450 nm as a blue laser may be used.
As the exposure device 30, for example, a surface-emitting laser light source of a multi-beam output type is also effective for color image formation.

-Developer-
Examples of the developing device 40 include a general developing device that develops a two-component developer in contact or non-contact. The developing device 40 is not particularly limited as long as it has a developing function, and is selected from known developing devices according to the purpose. For example, the developing device 40 includes a known developing device having a function of attaching a two-component developer to the electrophotographic photoreceptor 10 using a brush, a roller, or the like. The developing device 40 preferably uses a developing roller holding a developer on the surface.

-Transfer device-
As the transfer device 50, for example, a contact transfer charger using a belt, a roller, a film, a rubber blade or the like, or a known transfer charger such as a scorotron transfer charger using a corona discharge or a corotron transfer charger. Can be mentioned.

-Cleaning device-
The cleaning device 70 includes, for example, a casing 71, a cleaning blade 72, and a cleaning brush 73 disposed on the downstream side of the cleaning blade 72 in the rotation direction of the electrophotographic photosensitive member 10. Further, for example, a solid lubricant 74 is disposed in contact with the cleaning brush 73.

  Hereinafter, the operation of the image forming apparatus 101 according to the present embodiment will be described. First, the electrophotographic photoreceptor 10 rotates along the direction indicated by the arrow a, and at the same time is negatively charged by the charging device 20.

  The electrophotographic photoreceptor 10 whose surface is negatively charged by the charging device 20 is exposed by the exposure device 30, and a latent image is formed on the surface.

  When the portion where the latent image is formed on the electrophotographic photoreceptor 10 approaches the developing device 40, the developing device 40 (developing roll 411) attaches toner to the latent image and forms a toner image.

  When the electrophotographic photosensitive member 10 on which the toner image is formed is further rotated in the direction of arrow a, the toner image is transferred onto the recording paper P by the transfer device 50. As a result, a toner image is formed on the recording paper P.

  The toner image is fixed on the recording paper P on which the image is formed by the fixing device 60.

For example, as illustrated in FIG. 2, the image forming apparatus 101 according to the present embodiment includes an electrophotographic photosensitive member 10, a charging device 20, an exposure device 30, a developing device 40, and a cleaning device 70 in a housing 11. May be provided with a process cartridge 101 </ b> A in which are integrally stored. The process cartridge 101A integrally contains a plurality of members and is attached to and detached from the image forming apparatus 101.
The configuration of the process cartridge 101A is not limited to this. For example, the process cartridge 101A only needs to include at least the electrophotographic photoreceptor 10 and the developing device 40. In addition, for example, the charging device 20, the exposure device 30, the transfer device 50, and the cleaning At least one selected from the apparatus 70 may be provided.

  In addition, the image forming apparatus 101 according to the present embodiment is not limited to the above configuration, and is, for example, a cleaning device around the electrophotographic photosensitive member 10 and downstream of the transfer device 50 in the rotation direction of the electrophotographic photosensitive member 10. A first neutralization device may be provided on the upstream side of the rotation direction of the electrophotographic photosensitive member from 70 so that the polarity of the remaining toner is aligned and easy to remove with a cleaning brush. Alternatively, a configuration may be adopted in which a second static elimination device for neutralizing the surface of the electrophotographic photosensitive member 10 is provided on the downstream side in the rotation direction of the electrophotographic photosensitive member and on the upstream side in the rotational direction of the electrophotographic photosensitive member relative to the charging device 20. .

  The image forming apparatus 101 according to the present embodiment is not limited to the above-described configuration, and a known configuration, for example, a toner image formed on the electrophotographic photosensitive member 10 is transferred to the intermediate transfer member and then transferred to the recording paper P. An intermediate transfer type image forming apparatus or a tandem type image forming apparatus may be used.

EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all.
Unless otherwise specified, “part” means “part by mass” and {%} means “% by mass”.

[Preparation of various dispersions]
(Preparation of resin particle dispersion 1)
-Styrene (Wako Pure Chemical Industries): 320 parts-n-butyl acrylate (Wako Pure Chemical Industries): 80 parts-Beta carboxyethyl acrylate (Rhodia Nikka): 9 parts-1'10 Decanediol diacrylate (Shin Nakamura Chemical) Manufactured): 1.5 parts · Dodecanethiol (manufactured by Wako Pure Chemical Industries): 2.7 parts 4 parts of the anionic surfactant Dowfax (manufactured by Dow Chemical Co., Ltd.) is added to the above components mixed and dissolved. The solution dissolved in the part was added, dispersed and emulsified in the flask, and slowly stirred and mixed for 10 minutes. Further, 50 parts of ion-exchanged water in which 6 parts of ammonium persulfate was dissolved was added. Next, after sufficiently purging nitrogen in the flask sufficiently, the solution in the flask was heated with stirring in an oil bath to 70 ° C., and emulsion polymerization was continued as it was for 5 hours, and an anionic property with a solid content of 41%. A resin particle dispersion 1 was obtained.

  The resin particles in the resin particle dispersion 1 had a center particle size of 196 nm, a glass transition temperature of 51.5 ° C., and a weight average molecular weight Mw of 32400.

(Preparation of resin particle dispersion 2)
-Styrene (Wako Pure Chemical Industries): 280 parts-n-Butyl Acrylate (Wako Pure Chemical Industries): 120 parts-Beta Carboxyethyl Acrylate (Rhodia Nikka): 9 parts A solution obtained by dissolving 1.5 parts of the activator Dowfax (manufactured by Dow Chemical Co., Ltd.) in 550 parts of ion-exchanged water is dispersed and emulsified in a flask, stirred and mixed slowly for 10 minutes, and further 0.4 parts of ammonium persulfate. 50 parts of ion-exchanged water in which was dissolved was added. Next, after sufficiently replacing the nitrogen in the flask sufficiently, the solution in the flask was heated with stirring in an oil bath until it reached 70 ° C., and emulsion polymerization was continued as it was for 5 hours, and an anionic property with a solid content of 42%. A resin particle dispersion 2 was obtained.

  The resin particles in the resin particle dispersion 2 had a center particle size of 150 nm, a glass transition temperature of 53.2 ° C., a weight average molecular weight Mw of 41,000, and a number average molecular weight Mn of 25,000.

(Preparation of Colorant Particle Dispersion 1)
・ C. I. Pigment Yellow 74 pigment: 1 part by weight, anionic surfactant (manufactured by Nippon Oil & Fats Co., Ltd .: Nurex R): 2 parts, ion-exchanged water: 220 parts The above ingredients are mixed and mixed with a homogenizer (IKA Ultra Turrax). After pre-dispersion, the dispersion process is performed for 15 minutes at a pressure of 245 Mpa using an optimizer (counter-impact type wet pulverizer: Sugino Machine), and the colorant particle center particle size is 169 nm and the solid content is 22.0%. Agent particle dispersion 1 was obtained.

(Preparation of release agent particle dispersion 1)
Paraffin wax HNP9 (melting point 75 ° C .: manufactured by Nippon Seiki): 45 parts Cationic surfactant Neogen RK (Daiichi Kogyo Seiyaku): 5 parts Ion exchange water: 200 parts The above ingredients are mixed and heated to 100 ° C Then, after sufficiently dispersing with IKA's Ultra Turrax T50, it is dispersed with a pressure discharge type gorin homogenizer, and the release agent particles are dispersed with a center particle size of the release agent particles of 196 nm and a solid content of 22.0%. Liquid 1 was obtained.

[Production of toner particles]
(Production of toner particles (1))
-Resin particle dispersion 1: 107 parts-Resin particle dispersion 2: 35 parts-Colorant particle dispersion 1: 30 parts-Release agent particle dispersion 1: 91 parts A sufficiently mixed and dispersed solution was obtained with Tarax T50.
Next, 0.4 parts of polyaluminum chloride was added to this solution to produce core aggregated particles, and the dispersion operation was continued using an ultra turrax. Further, the solution in the flask was heated to 48 ° C. with stirring in an oil bath for heating and held at 48 ° C. for 50 minutes, and then 36 parts of the resin particle dispersion 1 was gently added to the core / shell aggregated particles. Was made. Thereafter, 0.5 mol / L sodium hydroxide aqueous solution was added to adjust the pH of the solution to 5.6, and then the stainless steel flask was sealed and heated to 96 ° C. while continuing stirring using a magnetic seal. After holding for a time, it was cooled.

  In this way, toner particles (1) were obtained.

(Toner particles (2))
Toner particles (2) were obtained in the same manner as toner particles (1) except that the temperature was maintained at 48 ° C. for 110 minutes.

(Toner particles (3))
Toner particles (3) were obtained in the same manner as toner particles (1) except that they were heated to 49 ° C. and held for 110 minutes.

[Preparation of external additives]
(Preparation of external additive (A1))
-Alkali catalyst solution preparation step [Preparation of alkali catalyst solution]-
200 parts by mass of methanol and 32.8 parts by mass of 10% ammonia water are placed in a 3 L glass reaction vessel having a metal stirring bar, dropping nozzle (Teflon (registered trademark) micro tube pump), and thermometer. The mixture was stirred and mixed to obtain an alkali catalyst solution.

-Particle generation step [Preparation of silica particle suspension]-
Next, the temperature of the alkali catalyst solution was adjusted to 25 ° C., and the alkali catalyst solution was purged with nitrogen. Then, while stirring the alkali catalyst solution, 450 parts by mass of tetramethoxysilane (TMOS) and 270 parts by mass of ammonia water having a catalyst (NH3) concentration of 4.44% were simultaneously added dropwise at the following supply amount to obtain silica. A suspension of particles (silica particle suspension) was obtained.
Here, the supply amount of tetramethoxysilane was 4.72 parts by mass / min, and the supply amount of 4.44% ammonia water was 2.83 parts by mass / min.

-Drying process-
Next, the obtained suspension of hydrophilic silica particles (hydrophilic silica particle dispersion) was dried by spray drying to remove the solvent to obtain hydrophilic silica particle powder.

-Hydrophobization process-
100 parts by mass of the obtained hydrophilic silica particle powder was put in a mixer and stirred at 200 rpm while heating to 200 ° C. in a nitrogen atmosphere, and hexamethyldisilazane (HMDS) was added to the hydrophilic silica particle powder in 30 parts. Part by mass was dropped and reacted for 2 hours. Thereafter, the silica particles were cooled and hydrophobic treated hydrophobic silica particles were obtained.

  The hydrophobic silica particles obtained through the above steps were used as an external additive (A1).

(Preparation of external additives (A2) to (A9))
External additives (A2) to (A9) were obtained in the same manner as in Example 1 except that various conditions in the alkali catalyst solution preparation step and the particle generation step were changed according to Table 2.

(Preparation of external additives (B1) to (B6))
External additives (B1) to (B6) shown in Table 4 were prepared.

[Production of toner]
(Toners (1) to (19))
The type and number of external additives according to Table 5 were externally added to 100 parts of toner particles according to Table 5 by stirring at 2500 rpm for 20 minutes using a 20 L Henschel mixer.
Then, coarse particles were removed using a sieve having an opening of 45 μm to prepare toners (1) to (19).

[Creation of carrier]
(Carrier (1))
Ferrite particles (volume average particle size: 25 m): 100 parts Toluene: 14 parts Styrene methacrylate copolymer (component ratio: 90/10): 0.5 parts First, the above components excluding ferrite particles are stirred for 10 minutes. To prepare a dispersed coating solution, and then put the coating solution and ferrite particles in a vacuum degassing kneader,
After stirring at 60 ° C. for 30 minutes, the carrier (1) was prepared by further depressurizing while heating and degassing and drying.

(Carrier (2))
Into a Henschel mixer, 500 parts of spherical magnetite particles having a particle size of 0.3 μm (volume average particle diameter) are added and stirred. Then, 2.0 parts of a titanate coupling agent is added, and the temperature is raised to 100 ° C. for 30 minutes. By mixing and stirring, 0.3 μm spherical magnetite particles (dispersion in a carrier) coated with a titanate coupling agent were obtained.
Next, 50 parts of phenol, 68 parts of 40% formalin, 500 parts of the above spherical magnetite particles subjected to lipophilic treatment, 14 parts of 30% ammonia water, and 70 parts of water are placed in a 1 L four-necked flask and mixed with stirring. did. Next, the temperature was raised to 82 ° C. over 60 minutes with stirring, and the reaction was continued for 90 minutes at the same temperature. Then, after cooling to 25 degreeC and adding 500 parts of water, the supernatant liquid was removed and the deposit was washed with water. This was dried at 160 ° C. under reduced pressure to obtain a core material.

(Preparation of raw material solution for coating layer formation)
The following components were stirred / dispersed with a stirrer for 60 minutes to prepare a coating layer forming raw material solution.
Toluene: 85 parts Styrene-methacrylate copolymer (component ratio 90:10): 16 parts

(Carrier production)
8.5 parts of the coating layer forming raw material solution and 100 parts of the core material are put into a vacuum degassing type kneader and stirred at an apparatus temperature of 100 ° C. until the core material temperature reaches 85 ° C., and then the pressure is reduced to 95 kPa. And degassed and dried for 15 minutes. Furthermore, carrier (2) was produced by passing through a mesh having an opening of 75 μm.

(Carrier (3))
Carrier (3) was obtained in the same manner as carrier (1) except that ferrite particles having a volume average particle diameter of 15 μm were used.

(Carrier (4))
Carrier (4) was obtained in the same manner as carrier (1) except that ferrite particles having a volume average particle size of 38 μm were used.

[Examples 1 to 13, Comparative Examples 1 to 6]
Developers (1) to (10) (10 parts of toner according to Table 5, 100 parts of carrier according to Table 5), stirring for 20 minutes at 40 rpm using a V-blender, and sieving with a sieve having a 177 μm mesh. 19) was obtained.
These developers were used as examples and comparative examples.

[Evaluation]
(Amount of fluid energy)
The amount of flow energy of the developer obtained in each example was measured by the method described above.

(Image quality evaluation)
After the developer obtained in each example was filled in a “700DCP” developer manufactured by Fuji Xerox Co., Ltd., left for one month under low temperature and low humidity (5 ° C., 10%), and the image density (area coverage) was 75%. 100 solid images were output continuously, the output image was visually confirmed, and image omission (white omission) was evaluated (image quality evaluation 1 in Table 7).
Similarly, after standing for one month at a low temperature and low humidity (5 ° C., 10%), a solid image with an image density (Erica coverage) of 55% was continuously output 100 sheets, and the output image was visually confirmed. Image omission (white omission) was evaluated (image quality evaluation 2 in Table 7).
The evaluation criteria are as follows.
A: The number of missing images (out of white) is 0 out of 100. ○: The number of out of images (out of white) is 100 or less. A: Out of 100 (out of white). ) Is 2 or more and 4 or less ×: The number of out of 100 images (missing white) is 5 or more

  Tables 1 to 7 show the details of the toner particles, the external additive, the toner, the carrier, and the developer, and the evaluation results of each example in a list.

  From the above results, compared to the comparative example, in this example, after leaving for one month at low temperature and low humidity (5 ° C. 10%), evaluation was made on the image omission (white omission) of a solid image having an image density (area coverage) of 75%. It can be seen that a good result was obtained together with the image quality evaluation 1 and the image quality evaluation 2 evaluated for image omission (white omission) of a solid image having an image density (Erica coverage) of 55% after being left for one month.

DESCRIPTION OF SYMBOLS 10 Electrophotographic photoreceptor 11 Case 20 Charging device 30 Exposure device 40 Developing device 50 Transfer device 60 Fixing device 70 Cleaning device 71 Case 72 Cleaning blade 73 Cleaning brush 74 Lubricant 101 Image forming device 101A Process cartridge P Recording paper

Claims (6)

A toner comprising toner particles and an external additive having a volume average particle size of 70 nm to 200 nm and an average circularity of 0.5 to 0.9;
Career,
Have
An electrostatic charge image developer having an aeration fluidity energy of 30 mJ or more and 70 mJ or less when measured with a powder rheometer under conditions of an air flow rate of 20 ml / min, a rotating blade tip speed of 100 mm / sec, and a rotating blade approach angle of -5 °. .   The electrostatic charge image developer according to claim 1, wherein the external additive is sol-gel silica particles. The toner further includes an external additive composed of vapor phase silica particles having a volume average particle diameter of 10 nm to 50 nm,
The toner particles are toner particles having an average circularity of 0.945 or more and 0.997 or less and a volume average particle size of 3.5 μm or more and 6.3 μm or less,
The electrostatic image developer according to claim 1, wherein the carrier is a carrier having a weight of 0.15 × 10 ⁻¹³ g or more and 0.83 × 10 ⁻¹³ g or less per carrier particle. An image carrier,
A developing unit that contains the electrostatic charge image developer according to any one of claims 1 to 3 and that develops an electrostatic latent image formed on the image carrier as a toner image by the electrostatic charge image developer. When,
Comprising at least
A process cartridge that is detachable from the image forming apparatus. An image carrier,
Charging means for charging the image carrier;
Electrostatic latent image forming means for forming an electrostatic latent image on the charged image carrier;
A developing unit that contains the electrostatic charge image developer according to any one of claims 1 to 3 and that develops an electrostatic latent image formed on the image carrier as a toner image by the electrostatic charge image developer. When,
Transfer means for transferring the toner image to a transfer object;
An image forming apparatus comprising at least A charging step for charging the image carrier;
An electrostatic latent image forming step of forming an electrostatic latent image on a charged image carrier;
A developing step of developing the electrostatic latent image formed on the image carrier as a toner image with the electrostatic charge image developer according to any one of claims 1 to 3,
A transfer step of transferring the toner image to a transfer target;
An image forming apparatus comprising at least