JP2024025273A - Toner, and image formation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner excellent in suppression of an external clinging additive ghost while suppressing scratches to a photoreceptor and toner fusion.

SOLUTION: A toner includes toner particles and an external additive including silica fine particles subjected to surface treatment and titanic acid compound particles on the surfaces of the toner particles. The DD/MAS measurement of solid ²⁹ Si-NMR of the silica particles observes a peak PD1 corresponding to a silicon atom in the D1 structure of a siloxane chain and a peak PD2 corresponding to a silicon atom in the D2 structure of the siloxane chain; when setting the area of the peak PD1 to SD1 and the area of the peak PD2 to SD2, SD1 and SD2 satisfy 1.2≤(SD1+SD2)/SD1≤10.0; the number average particle size of the primary particles of the titanic acid compound fine particles is 10 nm or more and 100 nm or less; and the average circularity of the primary particles of the titanic acid compound fine particles is 0.700 or more and 1.00 or less.

SELECTED DRAWING: None

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to toners and image forming methods used in electrophotographic systems, electrostatic recording systems, electrostatic printing systems, and the like.

In recent years, electrophotographic full-color copying machines have become widespread and are beginning to be applied to the printing market. In the printing market, there is a growing demand for high speed, high image quality, and high stability.
In order to achieve high image quality, it is necessary to stabilize the charging characteristics of toner. In order to stabilize the charging characteristics of toner, various studies have been conducted on external additives. For example, Patent Document 1 discloses a toner with improved charging characteristics by externally adding silica particles whose surface has been treated with cyclic siloxane. Patent Document 2 discloses that charging stability is improved by externally adding strontium titanate, in which the number average particle diameter of primary particles is 10 nm or more and 95 nm or less, and the half width of the diffraction angle in X-ray diffraction has a specific value. A toner that has been used has been disclosed.
On the other hand, in order to achieve high stability, a cleaning process for removing toner and external additives remaining on the photoreceptor without being transferred is important. When the toner on the photoreceptor is exposed to high temperatures, the toner fuses to the photoreceptor, causing image defects. Furthermore, some of the external additives added to the toner are detached and adhered onto the photoreceptor. In Patent Document 3, by externally adding lanthanum-doped titanate compound particles, the rounded titanate compound particles are detached from the photoreceptor, thereby preventing scratches on the photoreceptor in the cleaning process. A toner has been disclosed that has an improved effect of polishing toner and external additives adhering to a photoconductor without the need to apply the toner.

Japanese Patent Application Publication No. 2016-167029 Japanese Patent Application Publication No. 2022-22414 JP2022-34384A

However, as speeds increase, it has been found that when external additives with small particle diameters and round shapes, such as those disclosed in Patent Documents 2 and 3, are used, image unevenness may occur.
Possible causes of image unevenness are as follows. When images with clearly separated image areas and non-image areas are output continuously, a difference occurs in the amount of external additive that passes through the cleaning process and travels around on the photoreceptor. It has been found that when a halftone image is output in this state, image unevenness (hereinafter also referred to as external additive ghost) may occur.
The external additive entrainment ghost is an image defect that occurs when the external additive detached from the toner and adhered to the photoreceptor is not removed in the cleaning process and continues to circulate on the photoreceptor.
Blade cleaning is preferably used in the photoconductor cleaning process. When cleaning the photoreceptor with a blade, the angle and pressure at which the blade is pressed against the photoreceptor are important; however, if the pressure is too weak, the cleaning nip will not be able to remove toner or external additives; If the pressure is too high, the blade will chatter, allowing toner and external additives to slip through. It is possible to remove toner and external additives by setting the blade at an appropriate angle and pressure, but as the particle size of external additives becomes smaller and their shape becomes rounder, removal during the cleaning process becomes more difficult. , the amount that passes through increases.
Further improvements to the toner were essential in order to suppress scratches on the photoreceptor and toner fusion, as well as ghosts caused by external additives.

The present invention provides a toner comprising toner particles and an external additive on the surface of the toner particles,
The external additive has silica fine particles and titanic acid compound fine particles,
The silica fine particles are surface-treated treated silica fine particles,
In the DD/MAS measurement of the solid ²⁹ Si-NMR of the silica fine particles, there is a peak PD1 corresponding to the silicon atom represented by Si ^a in the structure represented by the following formula (1), and a peak PD1 corresponding to the silicon atom represented by the following formula (2). A peak PD2 corresponding to the silicon atom represented by Si ^b in the structure is observed, and when the area of the peak PD1 is SD1 and the area of the peak PD2 is SD2, the SD1 and the SD2 are
1.2≦(SD1+SD2)/SD1≦10.0
The filling,
The number average particle diameter of the primary particles of the titanate compound fine particles is 10 nm or more and 100 nm or less,
The present invention relates to a toner characterized in that the primary particles of the titanic acid compound fine particles have an average circularity of 0.700 or more and 1.00 or less.

（式（１）及び式（２）中、Ｒは、それぞれ独立して、水素原子、メチル基又はエチル基を表す。）
また、本発明は、感光体の表面の帯電を行う帯電工程、帯電された該感光体に静電潜像を形成する静電潜像形成工程、該静電潜像をトナーによって現像して該感光体表面にトナー画像を形成する現像工程、該トナー画像を、記録媒体に転写する転写工程、記録媒体上のトナー像を定着する定着工程、および該感光体にクリーニングブレードを当接し、該感光体上の残留トナーを除去するクリーニング工程、を有する画像形成方法において、
該トナーは、上記構成のトナーであることを特徴とする画像形成方法に関する。

(In formula (1) and formula (2), R each independently represents a hydrogen atom, a methyl group, or an ethyl group.)
The present invention also relates to a charging process of charging the surface of a photoconductor, an electrostatic latent image forming process of forming an electrostatic latent image on the charged photoconductor, and a process of developing the electrostatic latent image with toner. A developing step for forming a toner image on the surface of the photoreceptor, a transfer step for transferring the toner image onto a recording medium, a fixing step for fixing the toner image on the recording medium, and a cleaning blade is brought into contact with the photoreceptor to remove the toner image from the photoreceptor. An image forming method comprising a cleaning step of removing residual toner on the body,
The present invention relates to an image forming method characterized in that the toner has the above-mentioned structure.

According to the present invention, it is possible to provide a toner that suppresses scratches on the photoreceptor and toner fusion, and also suppresses ghosts caused by external additives. Furthermore, the same effect can be achieved by the image forming method of the present invention.

FIG. 3 is an explanatory diagram of a diameter a of silica particles and a portion b where silica particles are buried, which are necessary for calculating the embedding rate of silica particles on the surface of a toner particle. FIG. 2 is a schematic diagram of a heat treatment apparatus suitable for surface-treating toner particles to which fine silica particles have been externally added and mixed with hot air.

In the present invention, the descriptions such as "from XX to XX" and "XX to XX" indicating a numerical range mean a numerical range including the lower limit and upper limit, which are the endpoints, unless otherwise specified.

[Features of the present invention]
The inventors of the present invention have investigated toners that can provide high image quality and high stability even at higher speeds, and have found that a toner containing silica fine particles and a titanic acid compound having the structure of the present invention is used. It has been found that, over a long period of time, damage to the photoreceptor and toner fusion can be suppressed, and ghosts caused by external additives can be effectively suppressed.

The reason why the effects of the present invention were obtained is considered as follows.

In order to suppress scratches and toner fusion on the photoreceptor, titanate compound fine particles are added externally, and the number average particle size of the primary particles of the titanate compound fine particles is 10 nm or more and 100 nm or less, and the titanate compound fine particles are It is necessary that the average circularity of the primary particles of the compound fine particles is 0.700 or more and 1.00 or less.

Since the number average particle size of the primary particles of the titanic acid compound fine particles is 10 nm or more and 100 nm or less, when they are detached from the toner and attached to the photoreceptor surface, they tend to adhere uniformly to the photoreceptor surface, and the photoreceptor surface It exhibits a good polishing effect against the toner and prevents toner from adhering to the photoreceptor.

Furthermore, if the average circularity of the primary particles is 0.700 or more, it means that the shape of the titanic acid compound is round, which can suppress scratches on the photoreceptor and produce a better polishing effect. It can prevent toner from adhering to the body.

However, if an external additive with a number average particle diameter of 100 nm or less and a round shape is detached from the toner and adheres to the photoreceptor, it becomes difficult to remove in a cleaning process, and the amount of the additive slips through increases. When images with clearly separated image areas and non-image areas are output continuously, there are many titanate compound fine particle components detached from the toner in the image areas, and the amount of particles that slip through increases. A ghost appears around the additive.

The present inventors have conducted intensive studies to suppress ghosts caused by external additives, and have found that by using the titanic acid compound fine particles externally added together with silica fine particles having the structure of the present invention, the external additive component can be reduced. It has been found that the amount of particles that slip through can be suppressed, and ghost suppression caused by external additives can be better suppressed.

The silica fine particles of the present invention are surface-treated treated silica fine particles, and in solid ²⁹ Si-NMR DD/MAS measurement, the silicon atom represented by Si ^a in the structure represented by the following formula (1) A corresponding peak PD1 and a peak PD2 corresponding to the silicon atom represented by Si ^b in the structure represented by the following formula (2) are observed, the area of the peak PD1 is defined as SD1, and the area of the peak PD2 is defined as When SD2 is defined, the SD1 and the SD2 are
1.2≦(SD1+SD2)/SD1≦10.0
It is characterized by satisfying the following.

（式（１）及び式（２）中、Ｒは、それぞれ独立して、水素原子、メチル基又はエチル基を表す。）

(In formula (1) and formula (2), R each independently represents a hydrogen atom, a methyl group, or an ethyl group.)

The reason why the use of the silica fine particles of the present invention improved the suppression of ghosts accompanied by external additives is that the silica fine particles formed a strong layer of silica fine particles and titanate compound fine particles in the nip part of the cleaning blade. I think it's for the sake of it.

As a result, the amount of silica particles and titanate compound particles that slip through is reduced, and it is believed that the suppression of external additive slip-through ghosts is improved. Furthermore, since the titanic acid compound fine particles remained in the external additive layer, polishing properties on the photoreceptor were more effectively exhibited, and toner fusion adhesion to the photoreceptor was better suppressed.

The reason why the silica fine particles formed a strong layer of silica fine particles and titanic acid compound fine particles is not clear, but it is thought to be as follows.

The silica fine particles are surface-treated silica fine particles, and are characterized by having siloxane chains represented by formula (1) or formula (2). The siloxane chain can be distinguished into a D1 unit structure as shown in formula (1) and a D2 unit structure as shown in formula (2) in solid state ²⁹ Si-NMR DD/MAS measurement. Since the D1 unit structure indicates the terminal group of the surface treatment molecule, 1.2≦(SD1+SD2)/SD1≦10.0 in the present invention is an index representing the length of the siloxane chain.

In order for a layer of fine silica particles to be firmly formed in the cleaning nip, it is believed that the fine silica particles must be compacted in a form close to a close-packed structure and the adhesion of the silica must be high.

The silica fine particles of the present invention have a D1 unit structure of siloxane chain terminal groups. Since the D1 unit structure has a polar group OR (R=hydrogen atom, methyl group, or ethyl group) at the terminal, it is considered that the attractive force derived from the polar group acts strongly when it is compacted. In order to utilize the attractive force derived from polar groups, a certain length of siloxane chain is required for molecular mobility due to steric configuration, but if the siloxane chain is too long, the frequency of contact with polar groups decreases. do.

By controlling the length of the siloxane chain at 1.2≦(SD1+SD2)/SD1≦10.0, the silica fine particles of the present invention form a strong layer at the cleaning nip due to the attractive force of the silica fine particles when compacted. was able to form.

(SD1+SD2)/SD1 is preferably 1.2 or more and 6.3 or less, more preferably 1.2 or more and 3.8 or less. When (SD1+SD2)/SD1 is within the above range, the frequency of contact with the polar group increases and a stronger layer can be formed.

The value of (SD1+SD2)/SD1 can be adjusted by changing the type of surface treatment agent containing a siloxane bond, or by changing the temperature and time of surface treatment.

Furthermore, siloxane chains chemically bonded to the silica fine particle substrate are present on the surface of the silica fine particle substrate, and it is preferable that such siloxane chains exist in sufficient quantity.

The amount of siloxane chains present can be expressed as follows using the results of DD/MAS measurement of solid ²⁹ Si-NMR. In the DD/MAS measurement of solid ²⁹ Si-NMR, a peak PQ corresponding to the silicon atom represented by Si ^c in the structure represented by the following formula (3) is observed, and when the area of the peak PQ is taken as SQ , SD1, SD2, and SQ, the abundance (Ca) of siloxane chains is given by the following formula (a).
Ca=(SD1+SD2)/SQ×100 (a)

The silica fine particles preferably have Ca of 1.0 or more. Further, Ca is more preferably 4.0 or more, and even more preferably 5.0 or more. The upper limit of the amount of Ca present is 30.0 or less, considering that it is a surface treatment.

The "silicon atom represented by Si ^c in the structure represented by formula (3)" refers to a silicon atom having a so-called Q unit structure, and the above formula (a) is a silicon atom having a Q unit structure. It means the ratio of the amount of silicon atoms having the D unit structure to the amount of silicon atoms having the D unit structure. The silicon atoms in the silica fine particle base have a Q unit structure, and almost no silicon atoms have a D unit structure. Therefore, the silicon atoms of the D unit structure are considered to be derived from the surface treatment agent, and the above ratio represents the amount of siloxane chains derived from the surface treatment.

The fact that the siloxane chains are chemically bonded to the surface of the silica particles can be confirmed by washing the silica particles with a solvent (e.g., hexane) and confirming that the change in the amount of the treatment agent described above is small before and after washing. Can be verified.

The specific confirmation method is as follows.

Weigh 1.0 g of silica fine particles into a 50 ml screw tube, and add 20 ml of n-hexane. Thereafter, extraction was performed using an ultrasonic homogenizer (VP-050 manufactured by TAITEC) at intensity 20 (output 10 W) for 10 minutes. The obtained extract is separated using a centrifuge, the supernatant is removed, and normal hexane is distilled off from the obtained wet sample using an evaporator to obtain silica particles washed with hexane.

DD/MAS measurement of solid ²⁹ Si-NMR was performed using the silica fine particles washed with hexane, and the area of the peak PD1w corresponding to the silicon atom represented by Si ^a in the structure represented by formula (1) was determined. SD1w, the area SD2w of the peak PD2w corresponding to the silicon atom represented by Si ^b in the structure represented by formula (2), and the silicon atom represented by Si ^c in the structure represented by formula (3). The area SQw of the corresponding peak PQw is obtained. Using the obtained area SD1w, area SD2w, and area SQw, the abundance (Cb) of siloxane chains after hexane washing is calculated from the following formula (b).
Cb=(SD1w+SD2w)/SQw×100 (b)

From the above Ca and Cb and the following formula (c1), the rate of decrease ΔC in the amount of siloxane chains present after hexane washing relative to before hexane washing is determined.
ΔC (%) = (Ca-Cb)/Ca×100 (c1)

This reduction rate ΔC is considered to be the ratio of the amount of siloxane chains that are not chemically bonded to the surface of the silica fine particles to the amount of siloxane chains present on the surface of the silica fine particle substrate, and in the present invention, it is 30% or less. It is preferable that That is, Ca and Cb satisfy the following formula (c).
(Ca-Cb)/Ca×100≦30 (c)

Further, the reduction rate ΔC is preferably 0% or more and 20% or less, more preferably 0% or more and 5.0% or less, and even more preferably 0% or more and 1.0% or less.

When measuring the physical properties of the above-mentioned silica fine particles, if it is necessary to separate the silica fine particles from the toner particles, the measurement can be performed after separation by the method described below. In the separation method described below, since the separation is performed in an aqueous medium, the silicon compound does not elute into the medium. As a result, the silica particles can be separated from the toner particles while maintaining the physical properties of the silica particles before the separation step. Therefore, the values of each physical property measured using the silica fine particles separated from the toner particles are substantially the same as the values of each physical property measured using the silica fine particles before external addition.

(Method for separating silica particles from toner particles)
Weigh out 20 g of a 10% by mass aqueous solution of "Contaminon N" (pH 7 neutral detergent for cleaning precision measuring instruments, consisting of nonionic surfactant, anionic surfactant, and organic builder) into a 50 mL vial, and add 1 g of toner. Mix with.

Set in "KM Shaker" (model: V.SX) manufactured by Iwaki Sangyo Co., Ltd., set the speed to 50, and shake for 30 seconds. As a result, the silica fine particles migrate from the toner particle surface to the aqueous solution side. After that, in the case of magnetic toner containing a magnetic material, the toner particles are restrained using a neodymium magnet, the silica fine particles that have migrated to the supernatant liquid are separated, and the precipitated toner is vacuum-dried (40°C/24°C). The mixture is dried by drying for an hour) to obtain fine silica particles.

In the case of non-magnetic toner, fine silica particles transferred to the toner and supernatant liquid are separated using a centrifuge (H-9R; manufactured by Kokusan Co., Ltd.) at 1000 rpm for 5 minutes.

If external additives other than silica particles are externally added to the toner, the silica particles and other external additives can be separated by centrifuging the external additives separated from the toner using the method described above. Additives can be separated. Even if multiple types of silica fine particles are externally added to the toner, if they have different particle size ranges, they can be separated by centrifugation.For example, CS120FNX; manufactured by Hitachi Koki Co., Ltd. Separation can be carried out using the following conditions: 40,000 rpm for 20 minutes.

(Solid ²⁹ Si-NMR measurement method)
The specific measurement conditions for solid state ²⁹ Si-NMR are as follows.
Equipment: JNM-ECA400 (JEOL RESONANCE)
Calibration: TMS (tetramethylsilane) 0ppm
Temperature: Room temperature Measurement method: DD/MAS method ²⁹ Si 45°
Sample tube: Zirconia 8.0mmφ
Sample: Test tube filled with silica fine particles in powder state Sample rotation speed: 6kHz
relaxation delay: 90 seconds Scan: 5640

In the NMR spectrum obtained by the above measurement, by peak-separating the peak corresponding to the siloxane chain appearing around -20 ppm, the peak corresponding to the silicon atom having the D1 unit structure and the silicon having the PD1 and D2 unit structure are obtained. A peak PD2 corresponding to the atom is obtained, and the peak areas SD1 and SD2 are determined from each peak. Peak separation is performed using the following procedure.

(Peak separation method)
Peak separation is performed by analyzing the NMR spectrum data obtained by the above method. Peak separation may be performed using commercially available software or an independently created program as long as it is performed according to the procedure described below.

The peak positions are fixed at -18.2 ppm as the position of peak PD1 and -21.0 ppm as the position of peak PD2, and peak separation processing is performed using the Voigt function.

It is thought that the silica fine particles have a structure represented by the following formula (4). In the following formula (4), the leftmost silicon atom (Q unit structure) is the silicon of the silica fine particle substrate, and the portion bonded to it (D1 unit structure, D2 unit structure) is on the surface of the silica fine particle substrate. This is a site (siloxane chain) derived from a chemically bonded surface treatment agent. Although the value of n in formula (4) is not specified, considering that (SD1+SD2)/SD1 is 1.2 or more and 3.8 or less, and WD2 is 0.1 ppm or more and 6.0 ppm or less, It is assumed that n=1 or 2 is the center of the distribution of the value of n, and the distribution of the value of n is within the range of about n=0 to 5.

（式中のＲは、それぞれ独立して、水素原子、メチル基又はエチル基を示し、ｎは０以上（好ましくは０以上５以下）の整数である。）

(R in the formula each independently represents a hydrogen atom, a methyl group, or an ethyl group, and n is an integer of 0 or more (preferably 0 or more and 5 or less).)

[Silica fine particles]
The silica fine particles in the present invention will be explained.

The silica fine particles preferably have a compound having a siloxane structure on their surfaces. Moreover, it is preferable to obtain it by treating the surface of a silica fine particle substrate using a surface treatment agent containing a siloxane bond. That is, the silica fine particles are preferably treated with a surface treatment agent containing a siloxane bond.

In the present invention, when silica fine particles are surface-treated with a surface treatment agent containing a siloxane bond, the part derived from the surface treatment agent is referred to as silica fine particles. Silica fine particles before surface treatment are sometimes referred to as "silica fine particle base."

The surface treatment agent containing a siloxane bond is not particularly limited, and any known material can be used. In order to easily obtain the above-mentioned physical properties, it is preferable to perform a surface treatment on the silica fine particle substrate.

Surface treatment agents containing siloxane bonds include, for example, silicone oil such as dimethyl silicone oil; methyl hydrogen silicone oil, methylphenyl silicone oil, alkyl-modified silicone oil, chloroalkyl-modified silicone oil, chlorophenyl-modified silicone oil, fatty acid-modified silicone oil. , polyether-modified silicone oil, alkoxy-modified silicone oil, carbinol-modified silicone oil, amino-modified silicone oil, fluorine-modified silicone oil, and other silicone oils in which the side chains or terminals of dimethyl silicone oil are modified with organic groups; hexamethylcyclotri These are cyclic siloxanes such as siloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane.

The surface treatment agent containing a siloxane bond is preferably a cyclic siloxane. More preferred is a cyclic siloxane having up to 10-membered rings. In the cyclic siloxane, some of the methyl groups bonded to silicon atoms may have substituents. Moreover, among the cyclic siloxanes, at least one selected from the group consisting of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane is preferable. From the viewpoint of ease of control of (SD1+SD2)/SD1 and ease of purification, it is more preferable to include octamethylcyclotetrasiloxane.

The method for surface treating the silica fine particle substrate is not particularly limited, and can be carried out by bringing a surface treatment agent containing a siloxane bond into contact with the silica fine particle substrate. From the viewpoint of uniformly treating the surface of the silica fine particle substrate and easily achieving the above-mentioned physical properties, it is preferable to bring the surface treatment agent into contact with the silica fine particle substrate in a dry manner. As will be described later, examples include a method in which the vapor of the surface treatment agent is brought into contact with the silica fine particle substrate, or a method in which a undiluted solution of the surface treatment agent or a diluted solution with various solvents is sprayed and brought into contact with the silica fine particle substrate.

The treatment temperature is not particularly limited, as it varies depending on the reactivity of the surface treatment agent used. It is preferable to mix the silica fine particle substrate and the surface treatment agent and heat-treat the mixture at a temperature of 300° C. or higher. More preferably, the temperature is 310°C or more and 380°C or less.

The treatment time varies depending on the treatment temperature and the reactivity of the surface treatment agent used, but is preferably 5 minutes or more and 300 minutes or less, more preferably 30 minutes or more and 240 minutes or less, and even more preferably 60 minutes or more and 200 minutes or less. . It is preferable that the treatment temperature and treatment time of the surface treatment are within the above ranges from the viewpoint of sufficiently reacting the treatment agent with the silica fine particle substrate, ease of control of (SD1+SD2)/SD1, and production efficiency.

The surface treatment agent is preferably brought into contact with the silica fine particle substrate by contacting the vapor of the surface treatment agent under reduced pressure or in an inert gas atmosphere such as a nitrogen atmosphere. By using the method of contacting with steam, it is easy to remove the surface treatment agent that does not react with the surface of the silica fine particles. When using a method of contacting with vapor of a surface treatment agent, it is preferable to perform the treatment at a treatment temperature equal to or higher than the boiling point of the surface treatment agent. The contact with steam may be carried out in multiple steps (for example, 2 to 3 times).

The silica fine particles are obtained by treating a silica fine particle base with a cyclic siloxane, particularly preferably at a treatment temperature of 300° C. or higher.

Since the cyclic siloxane reacts with the SiOH group on the surface of the silica fine particle substrate through a ring-opening reaction, the D1 unit structure can be effectively obtained, and (SD1+SD2)/SD1 can be easily controlled.

On the other hand, the silicon atom having the terminal D1 unit structure that is generated due to ring opening tends to become a reaction point with other cyclic siloxanes, and the chain length tends to become long, but the treatment temperature must be 300°C or higher. Both the formation and cleavage of siloxane bonds occur. As a result, the siloxane chains have short chain lengths and are uniformly aligned, and the value of (SD1+SD2)/SD1 falls within a predetermined range.

When a cyclic siloxane is used as a surface treatment agent, the amount of the surface treatment agent is preferably 40 parts by mass or more and 150 parts by mass or less, more preferably 70 parts by mass or more and 140 parts by mass or less, based on 100 parts by mass of the silica fine particle substrate. In particular, when the surface is treated by contacting the cyclic siloxane with steam, it is preferably added in an amount of 70 parts by mass or more, more preferably 100 parts by mass or more, per 100 parts by mass of the silica fine particle substrate. Thereby, the silica fine particle substrate can be surface-treated more uniformly, and the amount of siloxane chains present (Ca) can be controlled to 1.0 or more.

In addition, when surface treatment is performed under reduced pressure, it is preferable that the pressure due to the vapor of the surface treatment agent in the container is 0.1 Pa or more and 100.0 Pa or less, and more preferably 1.0 Pa or more and 10.0 Pa or less. preferable. By setting the pressure within the above range, the frequency at which the vapor molecules of the surface treatment agent come into contact with each other is reduced, and chemical reactions between the surface treatment agents are suppressed. chemical reactions can be carried out preferentially.

Furthermore, reaction by-products generated by the chemical reaction between the silica fine particle substrate and the surface treatment agent can be easily removed from near the surface of the silica fine particle, making it easier for the surface treatment agent to come into contact with the surface of the silica fine particle substrate. The substrate can be surface-treated more uniformly.

In addition, when performing surface treatment under reduced pressure, before bringing the surface treatment agent into contact with the surface of the silica fine particle substrate, heat the silica fine particle substrate under reduced pressure to remove moisture etc. adsorbed on the surface of the silica fine particle substrate. It is preferable to perform deaeration treatment. By doing so, the surface treatment agent can more easily come into contact with the surface of the silica fine particle substrate, and the silica fine particle substrate can be surface-treated more uniformly. Furthermore, from the viewpoint of making it easier for the surface treatment agent to come into contact with the surface of the silica fine particle substrate, it is also preferable to repeat the degassing treatment and the surface treatment of the silica fine particles with the surface treatment agent.

When silicone oil is used as a surface treatment agent, the amount of the surface treatment agent is preferably 3 parts by mass or more and 25 parts by mass or less, more preferably 5 parts by mass or more and 20 parts by mass or less, based on 100 parts by mass of the silica fine particle substrate. By using the above addition amount, the surface of the silica fine particles can be uniformly treated.

The kinematic viscosity of the silicone oil at a temperature of 25° C. is preferably from 30 mm ² /s to 500 mm ² /s, more preferably from 30 mm ² /s to 200 mm ² /s, from the viewpoint of uniformly treating the surface of the silica particles.

By the method described above, it is possible to form siloxane chains in which (SD1+SD2)/SD1 is 1.2 or more and 10.0 or less on the surface of silica fine particles.

Furthermore, within the range that satisfies the provisions of the present invention, after obtaining silica fine particles by the method described above, further treatment may be performed using the surface treatment agent containing the siloxane bond described above. The method for carrying out the treatment is not particularly limited, and can be carried out, for example, by bringing a surface treatment agent containing a siloxane bond into contact with silica fine particles.

The silica fine particles have high hydrophobicity because the hydrogen atoms of the silanol groups of the silica fine particle base are substituted with the above-mentioned siloxane chains. The hydrophobicity of fine silica particles can be estimated by measuring the amount of water adsorbed by the fine silica particles. The silica fine particles preferably have a moisture adsorption amount of 0.010 cm ^{3 /m 2 or more and 0.100 cm 3 / m 2 or less per m 2 of} BET specific surface area at a temperature of 30° C. and a relative humidity of 80%. It is more preferably 0.020 cm ³ /m ² or more and 0.070 cm ³ /m ² or less, and even more preferably 0.030 cm ³ /m ² or more and 0.060 cm ³ /m ² or less.

The toner manufacturing method preferably includes a step of preparing silica fine particles and a step of mixing silica fine particles and toner particles to obtain a toner. Further, it is preferable that the toner manufacturing method includes a step of preparing silica fine particles obtained in the following step.

Preferably, in the step of preparing silica fine particles, a silica fine particle substrate is mixed with a surface treatment agent containing a siloxane bond (preferably a cyclic siloxane), and a heat treatment is performed at a temperature of 300°C or higher to coat the surface of the silica fine particle substrate. , a step of preparing silica fine particles by surface treating with a surface treating agent containing a siloxane bond.

The silica particulate substrate can be produced, for example, from fumed silica produced by burning a silicon compound, particularly a silicon halide, generally a silicon chloride, usually purified silicon tetrachloride, in an oxyhydrogen flame, or water glass. Examples include wet silica obtained by a wet method, sol-gel method silica particles, gel method silica particles, aqueous colloidal silica particles, alcoholic silica particles, fused silica particles obtained by a gas phase method, and deflagration method silica particles. Preferably it is fumed silica.

It is preferable that the silica fine particles are, for example, spherical silica fine particles. "Spherical" includes substantially spherical shapes such as slightly ellipsoidal shapes and shapes with slightly chipped parts. The average circularity of the silica fine particles is preferably 0.900 or more and 1.000 or less, more preferably 0.930 or more and 0.990 or less.

<Measurement method of water adsorption amount>
The amount of moisture adsorbed by the silica fine particles is measured using an adsorption equilibrium measuring device (BELSORP-aqua3: manufactured by Bell Japan Co., Ltd.). This device measures the adsorption amount of a target gas (water vapor).

(deaeration)
Degas the moisture adsorbed on the sample before measurement. Attach cell, filler lot, and cap and weigh empty. Weigh 0.3g of the sample and put it into the cell. Place the filler rod into the cell, attach the cap, and attach it to the degassing port. After attaching all the cells to be measured to the degassing ports, open the helium valve. Turn on the button for the port to be degassed and press the "VAC" button. This allows deaeration for over a day.

(measurement)
Turn on the power to the main unit (there is a switch on the back of the main unit). At the same time, the vacuum pump is also started. Turn on the power to the circulating water main body and operation panel. Launch "BELaqua3.exe" (measurement software) located in the center of the PC screen. Temperature control of the air high temperature tank: Double-click "SV" in the "TIC1" frame on the "Flow path diagram" window to open the "Temperature setting" window. Enter the temperature (80°C) and click Settings.

Adsorption temperature control: Double-click "SV" of "Adsorption temperature" in the "Flow path diagram" window and enter the "SV value" (adsorption temperature). Click "Circulation start" and "External temperature control" and click settings.

Press the "PURGE" button to stop degassing, turn off the port button, remove the sample, attach cap 2, weigh the sample, and then attach the sample to the measuring section of the main body. On the PC, click "Measurement conditions" to open the "Measurement condition settings" window. The measurement conditions are as follows.

Air constant temperature chamber temperature: 80.0°C, adsorption temperature: 30.0°C, adsorbate name: H ₂ O, equilibrium time: 500 sec, temperature waiting: 60 min, saturated vapor pressure: 4.245 kPa, sample tube pumping speed: normal , Chemical adsorption measurement: No, Initial introduction amount: 0.20cm ³ (STP)・g ^-1 , Number of measurement relative pressure ranges: 4

Select the number of samples to be measured and enter the "measurement data file name" and "sample weight." Start measurement.

(analysis)
Launch analysis software, perform analysis, and calculate the amount of water adsorption per unit mass (cm ³ /g) at a relative water vapor pressure of 80%. By dividing the calculated amount of water adsorption per unit mass by the BET specific surface area of the silica fine particles obtained by the method described below, the amount of water adsorption per surface area (cm ³ /m ² ) is determined.

<Measurement of BET specific surface area>
The BET specific surface area of silica fine particles can be determined by a low-temperature gas adsorption method using a dynamic constant pressure method according to the BET method (BET multipoint method). Using a specific surface area measuring device (product name: Gemini 2375 Ver. 5.0, manufactured by Shimadzu Corporation), nitrogen gas is adsorbed onto the sample surface, and the BET ratio is determined by measuring using the BET multipoint method. The surface area (m ² /g) can be calculated.

The number average particle diameter of the primary particles of silica fine particles is preferably 5 nm or more and 500 nm or less, more preferably 8 nm or more and 310 nm or less, even more preferably 50 nm or more and 300 nm or less, and particularly preferably 50 nm or more and 200 nm or less. As a result, the silica particles can appropriately cover the toner particles, and the silica particles attached to the photoreceptor can easily form a close-packed structure in the cleaning nip portion. As a result, it is possible to suppress the external additive from slipping through, and the ghost surrounding the external additive can be effectively suppressed.

The number average particle diameter of the primary particles of silica fine particles can be adjusted by controlling the conditions of the reaction step, crushing step, classification step, etc. in the silica fine particle manufacturing process.

[Titanic acid compound fine particles]
The titanate compound fine particles in the present invention have a number average particle size of primary particles of the titanate compound fine particles of 10 nm or more and 100 nm or less, and an average circularity of the primary particles of the titanate compound fine particles of 0.700 or more and 1 A value of .00 or less is necessary in order to suppress scratches on the photoreceptor and to achieve a good polishing effect on the surface of the photoreceptor.

The number average particle diameter of the primary particles of the titanate compound fine particles is preferably 10 nm or more and 70 nm or less, more preferably 10 nm or more and 50 nm or less. The number average particle size of the primary particles of the titanic acid compound fine particles can be controlled by the concentration of the raw materials, the reaction temperature, and the reaction time.

On the other hand, the average circularity of the titanic acid compound fine particles is preferably 0.800 or more and 0.930 or less, more preferably 0.800 or more and 0.900 or less. By controlling the average circularity within the above range, scratches on the photoreceptor, polishing effect, and ghost suppression caused by external additives passing through can be better suppressed.

In the present invention, the number average particle diameter A of the silica fine particles preferably has a relationship of A>B with respect to the number average particle diameter B of the primary particles of the titanic acid compound fine particles. Since the number average particle size A of the silica fine particles is larger than the number average particle size B of the titanate compound fine particles, the titanate compound fine particles are effectively captured by the silica layer in the cleaning nip, preventing them from slipping through. It is possible to suppress this and enhance the polishing effect of the photoreceptor.

The content of the titanic acid compound fine particles is preferably 0.05 parts by mass or more and 2.0 parts by mass or less, and preferably 0.1 parts by mass or more and 1.5 parts by mass or less, based on 100 parts by mass of the toner particles. More preferred.

As the titanate compound fine particles, potassium titanate, barium titanate, strontium titanate, calcium titanate, magnesium titanate, lead titanate, aluminum titanate, lithium titanate, etc. are used. In particular, strontium titanate and calcium titanate are preferred in terms of obtaining a polishing effect on the photoreceptor.

The titanic acid compound fine particles are preferably surface-treated for the purpose of hydrophobization and triboelectrification control, if necessary. That is, examples of the treatment agent include unmodified silicone varnish, various modified silicone varnishes, unmodified silicone oil, various modified silicone oils, silane coupling agents, silane compounds having functional groups, and other organosilicon compounds. It will be done. Various processing agents may be used in combination. Among these, treatment with a silane coupling agent is particularly preferred. That is, it is preferable that the titanic acid compound fine particles are surface-treated fine particles with a silane coupling agent.

Examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, β-(3,4epoxycyclohexyl)ethyltrimethoxysilane, and γ-glycidoxypropyltrimethoxysilane. Silane, γ-glycidoxypropylmethyldiethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, methyltrimethoxy Silane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, n-butyltrimethoxysilane, isobutyltrimethoxysilane, trimethylmethoxysilane , n-hexyltrimethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, hydroxypropyltrimethoxysilane, n-hexadecyltrimethoxysilane, n-octadecyltrimethoxysilane, Examples include trifluoropropyltrimethoxysilane and hydrolysates thereof.

Among these, n-octyltriethoxysilane, isobutyltrimethoxysilane, and trifluoropropyltrimethoxysilane are preferred, and isobutyltrimethoxysilane is more preferred. Further, these processing agents may be used alone or in combination of two or more.

The titanate compound fine particles may be doped with a metal element other than the element constituting the titanate. The metal element to be doped is not particularly limited, and examples thereof include lanthanum, silicon, aluminum, magnesium, calcium, manganese, rhodium, ruthenium, iridium, tantalum, chromium, antimony, nickel, rhodium, and niobium. Among these, lanthanum is preferred in terms of controlling circularity.

There are no particular restrictions on the method for preparing the titanate compound fine particles, but for example, strontium titanate is produced by the following method. Strontium nitrate, strontium chloride, etc. are added to a dispersion of titania sol obtained by adjusting the pH of a hydrous titanium oxide slurry obtained by hydrolyzing an aqueous titanyl sulfate solution, and after heating to the reaction temperature, an aqueous alkali solution is added. It can be synthesized by adding. Note that the reaction temperature is preferably 60 to 100°C.

In order to control the number average particle size and circularity of the primary particles, in the step of adding the alkaline aqueous solution, it is preferable that the time required for adding the alkaline aqueous solution is 60 minutes or less. Furthermore, in the step of adding the alkaline aqueous solution, it is preferable to perform the addition while applying ultrasonic vibration in order to control the circularity.

Further, it is preferable to add an alkaline aqueous solution and rapidly cool the aqueous solution after the reaction is completed in order to control the primary particle size and circularity. Examples of the rapid cooling method include a method of adding pure water cooled to 10° C. or lower until the desired temperature is reached. By rapidly cooling, circularity can be highly controlled in the cooling process.

<Number average particle size of external additive>
It can be determined by observing the toner particles using a scanning electron microscope (SEM) and measuring the number and particle diameter (maximum diameter) of the silica particles and titanic acid compound particles present on the surface of the toner particles. At this time, it can be confirmed that the object to be measured is a silica fine particle or a titanic acid compound fine particle using energy dispersive X-ray analysis (EDS) accompanying the SEM. Note that the value measured and averaged for 100 toner particles is defined as the number average particle diameter.

<Measurement of average circularity of external additives>
Silica fine particles and titanate compound fine particles are imaged using a scanning electron microscope (SEM) with an image magnification of 25,000 times and a pixel count of 1280 x 960 (the size of one pixel is approximately 4 nm x approximately 4 nm), and the acquired images are analyzed. The circularity is determined by analysis using the software Image J (available from https://imagej.nih.gov/ij/).

First, the outline of the silica fine particles or the titanic acid compound fine particles is extracted, and the projected area S and the peripheral length L thereof are measured.

Next, the equivalent circle diameter and circularity are determined using the area S and the perimeter L. Equivalent circle diameter is the diameter of a circle that has the same area as the projected area of the particle image, and circularity is calculated as the value obtained by dividing the perimeter of the circle found from the equivalent circle diameter by the perimeter of the projected particle image. It is defined and calculated using the following formula.
Circularity = 2 x (π x S) ^1/2 /L

The above circularity is calculated for at least 100 silica fine particles, and the arithmetic mean value thereof is taken as the average circularity of the silica fine particles or titanic acid compound fine particles.

[Materials of toner particles]
(Binder resin)
The toner particles contain a binder resin, and a known binder resin can be used for the toner particles. For example, examples of the binder resin include the following.

Styrene resin, styrene copolymer resin, polyester resin, polyol resin, polyvinyl chloride resin, phenol resin, natural resin-modified phenol resin, natural resin-modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, Polyurethane resin, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumaron indene resin, petroleum resin. Preferably used resins include styrene copolymer resins, polyester resins, and hybrid resins in which polyester resins and styrene copolymer resins are mixed or partially reacted. Preferably, polyester resin is used.

The components constituting the polyester resin will be explained in detail. Note that one or more of various components can be used as the following components depending on the type and use.

Examples of the divalent carboxylic acid component constituting the polyester resin include the following dicarboxylic acids or derivatives thereof. Benzenedicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and phthalic anhydride or their anhydrides or lower alkyl esters; Alkyldicarboxylic acids or their anhydrides or their anhydrides such as succinic acid, adipic acid, sebacic acid, and azelaic acid; Lower alkyl esters thereof; alkenylsuccinic acids or alkylsuccinic acids having an average carbon number of 1 or more and 50 or less, or anhydrides or lower alkyl esters thereof; unsaturated such as fumaric acid, maleic acid, citraconic acid, and itaconic acid Dicarboxylic acids or their anhydrides or their lower alkyl esters.

Examples of the alkyl group in the lower alkyl ester include a methyl group, an ethyl group, a propyl group, and an isopropyl group.

On the other hand, examples of the dihydric alcohol component constituting the polyester resin include the following.

Ethylene glycol, polyethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5 -Pentanediol, 1,6-hexanediol, neopentyl glycol, 2-methyl-1,3-propanediol, 2-ethyl-1,3-hexanediol, 1,4-cyclohexanedimethanol (CHDM), hydrogenated Bisphenol A, bisphenol represented by formula (I-1) and its derivatives: and diols represented by formula (I-2).

（式（Ｉ－１）中、Ｒはエチレン基又はプロピレン基であり、ｘ、ｙはそれぞれ０以上の整数であり、かつ、ｘ＋ｙの平均値は０以上１０以下である。）

(In formula (I-1), R is an ethylene group or a propylene group, x and y are each an integer of 0 or more, and the average value of x+y is 0 or more and 10 or less.)

（式（Ｉ－２）中、Ｒ’はエチレン基又はプロピレン基であり、ｘ’、ｙ’はそれぞれ０以上の整数であり、かつ、ｘ’＋ｙ’の平均値は０以上１０以下である。）

(In formula (I-2), R' is an ethylene group or a propylene group, x' and y' are each an integer of 0 or more, and the average value of x'+y' is 0 or more and 10 or less. .)

The constituent components of the polyester resin may include a trivalent or higher carboxylic acid component and a trivalent or higher alcohol component in addition to the above-mentioned divalent carboxylic acid component and divalent alcohol component.

Examples of the trivalent or higher carboxylic acid component include, but are not particularly limited to, trimellitic acid, trimellitic anhydride, pyromellitic acid, and the like. In addition, examples of trivalent or higher alcohol components include trimethylolpropane, pentaerythritol, glycerin, and the like.

The constituent components of the polyester resin may contain a monovalent carboxylic acid component and a monovalent alcohol component in addition to the above-mentioned compounds. Specifically, monovalent carboxylic acid components include palmitic acid, stearic acid, arachidic acid, behenic acid, cerotic acid, heptacanoic acid, montanic acid, melisic acid, lactacic acid, tetracontanoic acid, pentacontanoic acid, etc. Can be mentioned.

Further, examples of the monohydric alcohol component include behenyl alcohol, ceryl alcohol, mericyl alcohol, and tetracontanol.

(colorant)
The toner can be used as a magnetic one-component toner, a non-magnetic one-component toner, or a non-magnetic two-component toner.

When used as a magnetic one-component toner, magnetic iron oxide particles are preferably used as the colorant. The magnetic iron oxide particles contained in the magnetic single-component toner include magnetic iron oxides such as magnetite, maghemite, and ferrite, and magnetic iron oxides containing other metal oxides; metals such as Fe, Co, and Ni; Alloys of these metals with metals such as Al, Co, Cu, Pb, Mg, Ni, Sn, Zn, Sb, Be, Bi, Cd, Ca, Mn, Se, Ti, W, and V; Mixtures may be mentioned. The content of the magnetic iron oxide particles is preferably 30 parts by mass or more and 150 parts by mass or less based on 100 parts by mass of the binder resin.

Examples of colorants used in non-magnetic one-component toners and non-magnetic two-component toners include the following.

As the black pigment, carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black is used, and magnetic powder such as magnetite and ferrite is also used.

Pigments or dyes can be used as coloring agents suitable for yellow color. As a pigment, C. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 17, 23, 62, 65, 73, 74, 81, 83, 93, 94, 95, 97, 98, 109, 110, 111, 117, 120, 127, 128, 129, 137, 138, 139, 147, 151, 154, 155, 167, 168, 173, 174, 176, 180, 181, 183, 191, C. I. Bat Yellow 1, 3, and 20 are listed. As a dye, C. I. Examples include Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162 and the like. These materials may be used alone or in combination of two or more.

Pigments or dyes can be used as colorants suitable for cyan color. As a pigment, C. I. Pigment Blue 1, 7, 15, 15; 1, 15; 2, 15; 3, 15; 4, 16, 17, 60, 62, 66, etc., C.I. I. Bat Blue 6, C. I. Acid Blue 45 is mentioned. As a dye, C. I. Examples include Solvent Blue 25, 36, 60, 70, 93, and 95. These materials may be used alone or in combination of two or more.

Pigments or dyes can be used as colorants suitable for magenta color. As a pigment, C. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48, 48; 2, 48; 3, 48; 4, 49, 50, 51, 52, 53, 54, 55, 57, 57; 1, 58, 60, 63, 64, 68, 81, 81; 1, 83, 87, 88, 89, 90, 112, 114, 122, 123, 144, 146, 150, 163, 166, 169, 177, 184, 185, 202, 206, 207, 209, 220, 221, 238, 254, etc., C. I. Pigment Violet 19; C. I. Bat Red 1, 2, 10, 13, 15, 23, 29, and 35 are mentioned.

As magenta dye, C. I. Solvent red 1, 3, 8, 23, 24, 25, 27, 30, 49, 52, 58, 63, 81, 82, 83, 84, 100, 109, 111, 121, 122, etc., C.I. I. Disperse Red 9, C. I. Solvent Violet 8, 13, 14, 21, 27, etc., C.I. I. Oil-soluble dyes such as Disperse Violet 1, C.I. I. Basic Red 1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37, 38, 39, 40, etc. I. Examples include basic dyes such as basic violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27, and 28. These materials may be used alone or in combination of two or more.

The content of the colorant is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin.

(Release agent)
A release agent (wax) may be used to impart release properties to the toner.

Examples of waxes include: Aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, olefin copolymers, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax; Oxidized waxes of aliphatic hydrocarbon waxes such as oxidized polyethylene wax; Carnauba wax , waxes mainly composed of fatty acid esters such as behenyl behenate, and montanate wax; and waxes that are partially or completely deoxidized from fatty acid esters such as deoxidized carnauba wax.

In addition, saturated straight chain fatty acids such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids such as brassic acid, eleostearic acid, and valinaric acid; stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnaubil alcohol, and seryl alcohol. , saturated alcohols such as mericyl alcohol; polyhydric alcohols such as sorbitol; fatty acid amides such as linoleic acid amide, oleic acid amide, lauric acid amide; methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide Acid amide, saturated fatty acid bisamides such as hexamethylene bisstearic acid amide; ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyladipic acid amide, N,N'-dioleylsebacic acid amide Unsaturated fatty acid amides such as m-xylene bisstearamide, aromatic bisamides such as N,N'-distearyl isophthalic acid amide; fatty acids such as calcium stearate, calcium laurate, zinc stearate, magnesium stearate, etc. Metal salts (generally referred to as metal soaps); Waxes made by grafting aliphatic hydrocarbon waxes with vinyl copolymer monomers such as styrene and acrylic acid; Fatty acids and polyhydric acids such as behenic acid monoglyceride Examples include partially esterified alcohols; methyl ester compounds having a hydroxyl group obtained by hydrogenating vegetable oils and fats.

Particularly preferably used waxes are aliphatic hydrocarbon waxes. For example, low molecular weight hydrocarbons obtained by radical polymerization of alkylene under high pressure or polymerization under low pressure with Ziegler catalyst or metallocene catalyst; Fischer-Tropsch wax synthesized from coal or natural gas; paraffin wax; thermal decomposition of high molecular weight olefin polymers. Olefin polymers obtained by: Synthetic hydrocarbon waxes obtained from distillation residues of hydrocarbons obtained by the Age method from synthesis gas containing carbon monoxide and hydrogen, or synthetic hydrocarbon waxes obtained by hydrogenating these are preferred. .

Furthermore, those obtained by fractionating the hydrocarbon wax by using a press perspiration method, a solvent method, a vacuum distillation method, or a fractional crystallization method are more preferably used. Among paraffin waxes, n-paraffin wax and Fischer-Tropsch wax, which mainly contain linear components, are particularly preferred from the viewpoint of molecular weight distribution.

These waxes may be used alone or in combination of two or more. The wax is preferably added in an amount of 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin.

(Charge control agent)
A charge control agent may be used in the toner. Known charge control agents can be used. For example, azo iron compounds, azo chromium compounds, azo manganese compounds, azo cobalt compounds, azo zirconium compounds, chromium compounds of carboxylic acid derivatives, zinc compounds of carboxylic acid derivatives, aluminum compounds of carboxylic acid derivatives, carboxylic acids Examples include derivative zirconium compounds. The carboxylic acid derivative is preferably an aromatic hydroxycarboxylic acid. Further, a charge control resin can also be used. If necessary, one type or two or more types of charge control agents may be used in combination. The charge control agent is preferably used in an amount of 0.1 parts by mass or more and 10 parts by mass or less based on 100 parts by mass of the binder resin.

[Addition of external additive to toner particles]
(Additional amount/addition method)
The toner has toner particles and fine silica particles and fine titanate compound particles on the surface of the toner particles. The toner can be obtained by externally adding silica particles and titanic acid compound particles as external additives to toner particles. The content of silica fine particles in the toner is preferably 0.01 parts by mass or more and 10.00 parts by mass or less, more preferably 1.00 parts by mass or more and 8.00 parts by mass or less, based on 100 parts by mass of toner particles. More preferably .00 parts by mass or more and 6.00 parts by mass or less.

This allows the silica fine particles to cover the toner particles more fully, and also allows the amount of adhesion to the photoreceptor to be appropriately controlled, allowing a stronger layer to be formed in the cleaning nip area, and allowing external additives to coat the toner particles more fully. Good suppression of ghosts around drugs.

The content of the titanic acid compound fine particles in the toner is preferably 0.05 parts by mass or more and 2.00 parts by mass or less, and 0.10 parts by mass or more and 1.50 parts by mass or less, based on 100 parts by mass of toner particles. More preferred.

External addition of external additives such as silica fine particles and titanic acid compound fine particles to toner particles can be carried out by mixing the toner particles and the external additive using a mixer as described below.

Examples of mixers include: Henschel mixer (manufactured by Mitsui Mining Co., Ltd.); Super mixer (manufactured by Kawata Co., Ltd.); Ribocone (manufactured by Okawara Seisakusho Co., Ltd.); Nauta mixer, turbulizer, cyclomix (manufactured by Hosokawa Micron Co., Ltd.); Spiral pin mixer (manufactured by Taiheiyo Kiko Co., Ltd.) ; Loedige mixer (manufactured by Matsubo).

(Burial rate of silica particles)
It is preferable that a portion of the silica particles be buried in the surface of the toner particles. Regarding the silica particles embedded in the surface of the toner particles, the embedding ratio of the silica particles to the toner particles is preferably 5% or more and 50% or less, more preferably 5% or more and 40% or less, and 10% or more and 30% or more. % or less, particularly preferably 12% or more and 25% or less, and particularly preferably 14% or more and 20% or less.

When the burial rate is within the above range, the adhesion force of toner adhering to the surface of the photoreceptor can be effectively lowered, and toner fusion can be suppressed.

<Calculation of burying rate of silica particles on the surface of toner particles>
First, as a pretreatment, silica fine particles that are not buried or have a small burial rate are separated from the toner. Weigh out 20 g of a 10% by mass aqueous solution of "Contaminon N" (pH 7 neutral detergent for cleaning precision measuring instruments, consisting of nonionic surfactant, anionic surfactant, and organic builder) into a 50 mL vial, and add 1 g of toner. Mix with.

Set in "KM Shaker" (model: V.SX) manufactured by Iwaki Sangyo Co., Ltd., set the speed to 50, and shake for 30 seconds. As a result, the unburied silica fine particles move from the toner particle surface to the aqueous solution side.

After that, in the case of magnetic toner containing a magnetic material, the toner particles are restrained using a neodymium magnet, the silica particles that have migrated to the supernatant liquid are separated, and the precipitated toner particles are vacuum-dried (40°C/ 24 hours) to dry it and use it as a sample.

In the case of non-magnetic toner, use a centrifuge (H-9R; manufactured by Kokusan Co., Ltd.) (1000 rpm for 5 minutes) to separate the toner particles and the unburied silica particles that have migrated to the supernatant liquid. do. The remaining toner particles are filtered by suction to collect powder of toner particles and dried.

The toner particles are fixed on a sample stage of an electron microscope using carbon tape, and the toner particles are observed under the following conditions. An image is taken by selecting a location where the toner particle surface has a large inclination angle (for example, 70 to 110 degrees, preferably about 90 degrees).
・Equipment used: SU8220 manufactured by Hitachi High Technologies
Acceleration voltage: 2kV
Emission current: 10μA
Image acquisition: Secondary electron detector Image magnification: 50,000 times Number of pixels: 1280 x 960 (1 pixel size is approximately 2 nm x approximately 2 nm)

The acquired image is analyzed using image analysis software Image J (available from https://imagej.nih.gov/ij/). As shown in Figure 1, fit the silica particles in a perfect circle (create a perfect circle using [Oval selections] (operate while holding down the shift key to fix the shape to a perfect circle)), and set the diameter a of the silica particles and the silica particles. The burying rate is calculated from the length b of the part where the fine particles are buried using the following formula. The length b shall be measured on a straight line passing through the top of the buried side in the depth direction and the center of the silica fine particle in a perfectly circular fitted silica fine particle.
Burial rate (%) = length b of the part where the silica fine particles are buried / diameter a of the silica fine particles

The above-mentioned burial rate is calculated for at least 100 silica fine particles, and the arithmetic mean value thereof is taken as the burial rate of the silica fine particles.

The embedding rate of the silica particles can be controlled, for example, by adjusting the temperature when toner particles and silica particles are mixed in the mixer as described above. Alternatively, after mixing toner particles and silica particles, surface treatment of the toner particles (silica particle embedding treatment) can be performed, and the control can be performed by adjusting the conditions (temperature of the processing atmosphere, exhaust air volume of the processing space). The surface treatment is preferably heat treatment. For example, a method of processing with hot air can be mentioned. When mixing toner particles and silica particles, titanic acid compound particles may also be mixed.

(Surface treatment of toner particles)
Surface treatment of toner particles can be performed using the following apparatus. Hybridization System (manufactured by Nara Kikai Seisakusho), Nobilta (manufactured by Hosokawa Micron), Mechano Fusion System (manufactured by Hosokawa Micron), Faculty (manufactured by Hosokawa Micron), Innomizer (manufactured by Hosokawa Micron), Theta Composer (manufactured by Tokuju Kosho) , Mechano Mill (manufactured by Okada Seiko Co., Ltd.), Meteor Rainbow MR Type (manufactured by Nippon Pneumatic Co., Ltd.).

Incidentally, after the silica fine particles and the titanic acid compound fine particles are subjected to the embedding treatment step in the manner described above, the silica fine particles and the titanic acid compound fine particles may be further externally added.

Hereinafter, a method of surface treating toner particles (for example, toner particles to which fine silica particles are externally added and mixed) with hot air using the heat treatment apparatus shown in FIG. 2 will be specifically illustrated. In this example, toner particles are referred to as the object to be processed.

The material to be treated is quantitatively supplied by the raw material quantitative supply means 1 and guided by compressed gas adjusted by the compressed gas flow rate adjustment means 2 to the introduction pipe 3 installed on the vertical line of the raw material supply means. The material to be treated that has passed through the introduction pipe 3 is uniformly dispersed by a conical protruding member 4 provided at the center of the raw material supply means, and is guided to supply pipes 5 extending in eight directions that extend radially to undergo heat treatment. It is guided to the processing chamber 6.

At this time, the flow of the processed material supplied to the processing chamber 6 is regulated by a regulating means 9 provided in the processing chamber 6 for regulating the flow of the processed material. Therefore, the object to be processed supplied to the processing chamber 6 is heat-treated while rotating inside the processing chamber 6, and then cooled.

The supplied hot air for heat-treating the object to be processed is supplied from the hot air supply means 7 and distributed by the distribution member 12, and the hot air is spiraled into the processing chamber 6 by the swirling member 13 for swirling the hot air. It is introduced by rotating it. As for its structure, the rotating member 13 for swirling the hot air has a plurality of blades, and the swirling of the hot air can be controlled by the number and angle of the blades (note that 11 indicates the outlet of the hot air supply means). show).

The temperature of the hot air supplied into the processing chamber 6 at the outlet of the hot air supply means 7 is preferably 100°C or more and 300°C or less, more preferably 130°C or more and 190°C or less. If the temperature at the outlet of the hot air supply means 7 is within the above range, it is possible to prevent fusion and coalescence caused by overheating the object to be treated, and to maintain the embedding rate of the silica particles within a preferable range. . Hot air is supplied from hot air supply means 7.

Further, the heat-treated resin particles are cooled by the cold air supplied from the cold air supply means 8. The temperature of the cold air supplied from the cold air supply means 8 is preferably -20°C or more and 30°C or less. If the temperature of the cold air is within the above range, the heat-treated workpiece can be efficiently cooled, and it is thought that fusion or coalescence of the workpiece is unlikely to occur. Further, the absolute moisture content of the cold air is preferably 0.5 g/m ³ or more and 15.0 g/m ³ or less.

Next, the cooled object to be processed is recovered by a recovery means 10 located at the lower end of the processing chamber 6. Note that a blower (not shown) is provided at the tip of the collecting means 10, and the collecting means 10 is configured to be sucked and transported by the blower (not shown).

Further, the powder particle supply port 14 is provided so that the swirling direction of the supplied processed material and the swirling direction of the hot air are the same, and the collecting means 10 is also provided in the rotating direction of the swirled processed material. It is provided in the tangential direction on the outer periphery of the processing chamber 6 so as to maintain . Furthermore, the cold air supplied from the cold air supply means 8 is configured to be supplied horizontally and tangentially from the outer peripheral part of the apparatus to the peripheral surface of the processing chamber.

The swirling direction of the object to be processed supplied from the powder particle supply port 14, the swirling direction of the cold air supplied from the cold air supply means 8, and the swirling direction of the hot air supplied from the hot air supply means 7 are all the same direction. Therefore, turbulence does not occur in the processing chamber, the swirling flow within the device is strengthened, and a strong centrifugal force is applied to the processed material before heat treatment, further improving dispersibility, resulting in toner particles with fewer coalesced particles. It's easy to get caught.

[Method for manufacturing toner particles]
In the step of obtaining toner particles, the method for producing toner particles is not particularly limited, and any known method can be used. Examples include a pulverization method, an emulsion aggregation method, a suspension polymerization method, a dissolution suspension method, and the like.

(Crushing method)
Toner particles produced by the pulverization method are produced, for example, as follows.

A binder resin, a colorant, and other additives as necessary are sufficiently mixed using a mixer such as a Henschel mixer or a ball mill. The mixture is melt-kneaded using a heat kneader such as a twin-screw extruder, heated roll, kneader, or extruder. At that time, wax, magnetic iron oxide particles, and metal-containing compounds can also be added.

After the melt-kneaded product is cooled and solidified, it is pulverized and classified to obtain toner particles. At this time, by adjusting the exhaust temperature during pulverization, the embedding rate of the silica fine particles on the surface of the toner particles can be controlled. A toner can be obtained by mixing toner particles and external additives such as silica particles using a mixer such as a Henschel mixer.

Examples of mixers include: Henschel mixer (manufactured by Mitsui Mining Co., Ltd.); Super mixer (manufactured by Kawata Co., Ltd.); Ribocone (manufactured by Okawara Seisakusho Co., Ltd.); Nauta mixer, turbulizer, cyclomix (manufactured by Hosokawa Micron Co., Ltd.); Spiral pin mixer (manufactured by Taiheiyo Kiko Co., Ltd.) ; Loedige mixer (manufactured by Matsubo).

Examples of the kneading machine include the following. KRC kneader (manufactured by Kurimoto Iron Works); Bussco kneader (manufactured by Buss); TEM extruder (manufactured by Toshiba Machinery Co., Ltd.); TEX twin-screw kneader (manufactured by Japan Steel Works, Ltd.); PCM kneader (manufactured by Ikegai) (manufactured by Tekkosho Co., Ltd.); Three roll mill, mixing roll mill, kneader (manufactured by Inoue Seisakusho Co., Ltd.); Kneedex (manufactured by Mitsui Mining Co., Ltd.); MS type pressure kneader, kneader-ruder (manufactured by Moriyama Seisakusho Co., Ltd.); Banbury mixer (manufactured by Kobe Steel Co., Ltd.) (manufactured by Shosha).

Examples of the crusher include the following: Counter jet mill, Micron jet, Innomizer (manufactured by Hosokawa Micron); IDS type mill, PJM jet crusher (manufactured by Nippon Pneumatic Industries); Cross jet mill (manufactured by Kurimoto Iron Works); Ulmax (manufactured by Nisso Engineering) ); SK Jet-O-Mill (manufactured by Seishin Enterprises); Kryptron (manufactured by Kawasaki Heavy Industries); Turbo Mill (manufactured by Turbo Industries); Super Rotor (manufactured by Nisshin Engineering).

In addition, after crushing, if necessary, hybridization system (manufactured by Nara Kikai Seisakusho), Nobilta (manufactured by Hosokawa Micron), Mechano Fusion System (manufactured by Hosokawa Micron), Faculty (manufactured by Hosokawa Micron), Innomizer (manufactured by Hosokawa Micron), , Theta Composer (manufactured by Tokuju Kosho Co., Ltd.), Mechanomill (manufactured by Okada Seiko Co., Ltd.), and Meteor Rainbow MR Type (manufactured by Nippon Pneumatic Co., Ltd.) are used to perform surface treatment on toner particles, and bury silica particles on the surface of toner particles. You can also control the rate.

Examples of classifiers include the following: Cruseal, Micron Crusifier, Spedic Classifier (manufactured by Seishin Enterprise Co., Ltd.); Turbo Crusifier (manufactured by Nisshin Engineering Co., Ltd.); Micron Separator, Turboplex (ATP), TSP Separator (manufactured by Hosokawa Micron Co., Ltd.); Elbow Jet (manufactured by Nisshin Engineering Co., Ltd.); dispersion separator (manufactured by Nippon Pneumatic Industries); YM Microcut (manufactured by Yaskawa Shoji).

Sieving devices used to screen out coarse particles include the following: Ultrasonic (manufactured by Koei Sangyo Co., Ltd.); Resona Sieve, Gyro Shifter (manufactured by Tokuju Kogyo Co., Ltd.); Vibrasonic System (manufactured by Dalton Co., Ltd.); Sonic Clean (manufactured by Shinto Kogyo Co., Ltd.); Turbo Screener (manufactured by Turbo Egyo Co., Ltd.); Microsifter (manufactured by Makino Sangyo Co., Ltd.); circular vibrating sieve.

(Emulsification aggregation method)
Toner particles are produced by the emulsion aggregation method, for example, as follows.

・Process of preparing resin fine particle dispersion (preparation process):
For example, as a binder resin component, polyester resin or styrene acrylic resin is dissolved in an organic solvent to form a uniform solution. Thereafter, a basic compound and a surfactant are added as necessary. An aqueous medium is slowly added to this solution while applying shear force using a homogenizer or the like to form resin fine particles of a binder resin. Finally, the organic solvent is removed to prepare a resin particle dispersion in which the resin particles are dispersed.

When preparing the resin fine particle dispersion, the amount of the resin component to be dissolved in the organic solvent is preferably 10 parts by mass or more and 50 parts by mass or less, and 30 parts by mass or more and 50 parts by mass, based on 100 parts by mass of the organic solvent. It is more preferable that it is below.

Any organic solvent can be used as long as it can dissolve the resin component, but solvents with high solubility for olefin resins such as toluene, xylene, and ethyl acetate are preferred.

The surfactant is not particularly limited. For example, sulfate-based, sulfonate-based, carboxylate-based, phosphate-based, soap-based anionic surfactants; cationic surfactants such as amine salts and quaternary ammonium salts; polyethylene glycol-based, Examples include alkylphenol ethylene oxide adduct-based and polyhydric alcohol-based nonionic surfactants.

Examples of the basic compound include inorganic bases such as sodium hydroxide and potassium hydroxide, and organic bases such as triethylamine, trimethylamine, dimethylaminoethanol, and diethylaminoethanol. These basic compounds may be used alone or in combination of two or more.

・Agglomeration process:
In the aggregation step, for example, a colorant fine particle dispersion, a wax fine particle dispersion, and a silicone oil emulsion are mixed with the resin fine particle dispersion to prepare a mixed liquid, and then the prepared mixture This is a process in which fine particles contained in a liquid are aggregated to form aggregate particles.

A suitable example of a method for forming aggregate particles is a method in which a flocculant is added and mixed into the above-mentioned liquid mixture, and the temperature is increased or mechanical power is appropriately applied.

The colorant fine particle dispersion is prepared by dispersing the colorant described above. The colorant fine particles are dispersed by a known method, and for example, a rotary shear type homogenizer, a media type dispersion machine such as a ball mill, a sand mill, an attritor, a high pressure opposing collision type disperser, etc. are preferably used. Further, a surfactant or a polymer dispersant that imparts dispersion stability can be added as necessary.

The wax fine particle dispersion and the silicone oil emulsion are prepared by dispersing each material in an aqueous medium. Each material is dispersed by a known method, for example, a rotary shear type homogenizer, a media type disperser such as a ball mill, a sand mill, an attritor, a high-pressure opposed collision type disperser, etc. are preferably used. Further, a surfactant or a polymer dispersant that imparts dispersion stability can be added as necessary.

Examples of flocculants include metal salts of monovalent metals such as sodium and potassium; metal salts of divalent metals such as calcium and magnesium; metal salts of trivalent metals such as iron and aluminum; polyaluminum chloride, etc. Examples include polyvalent metal salts. From the viewpoint of particle size controllability in the aggregation step, metal salts of divalent metals such as calcium chloride and magnesium sulfate are preferred.

The addition and mixing of the flocculant is preferably carried out at a temperature range from room temperature to 75°C. When the above-mentioned mixing is performed under this temperature condition, aggregation proceeds in a stable state. The above mixing can be performed using a known mixing device, homogenizer, mixer, etc.

・Fusion process:
The fusion step is a step in which the aggregate particles are preferably heated to a temperature higher than the melting point of the olefin resin and fused to produce particles with smoothed aggregate particle surfaces.

Before entering the fusion step, a chelating agent, a pH adjuster, a surfactant, etc. can be added as appropriate to prevent fusion between the obtained resin particles.

Examples of chelating agents include ethylenediaminetetraacetic acid (EDTA) and its alkali metal salts such as its Na salt, sodium gluconate, sodium tartrate, potassium and sodium citrate, nitrilotriacetate (NTA) salts, both COOH and OH. A number of water-soluble polymers (polyelectrolytes) containing the functionality of

A short time is sufficient for the fusion process if the heating temperature is high, and a long time is required if the heating temperature is low. That is, the time for heating and fusion depends on the heating temperature and cannot be absolutely defined, but it is generally about 10 minutes to 10 hours.

・Cooling process:
This is a step of cooling the temperature of the aqueous medium containing the resin particles obtained in the fusion step. Although not particularly limited, a specific cooling rate is about 0.1 to 50°C/min.

・Cleaning process:
By repeatedly washing and filtering the resin particles produced through the above steps, impurities in the resin particles can be removed.

Specifically, it is preferable to wash the resin particles using an aqueous solution containing a chelating agent such as ethylenediaminetetraacetic acid (EDTA) and its Na salt, and then wash the resin particles with pure water.

By repeating washing with pure water and filtration multiple times, metal salts, surfactants, etc. in the resin particles can be removed. The number of times of filtration is preferably 3 to 20 times from the viewpoint of production efficiency, and more preferably 3 to 10 times.

・Drying and classification process:
Toner particles can be obtained by drying the washed resin particles and appropriately classifying them.

(dissolution suspension method)
Toner particles produced by the dissolution/suspension method are produced, for example, as follows.

In the dissolution/suspension method, a resin composition obtained by dissolving a binder resin component such as polyester resin or styrene acrylic resin in an organic solvent is dispersed in an aqueous medium to granulate particles of the resin composition. After that, toner particles are manufactured by removing the organic solvent contained in the particles of the resin composition.

The dissolution/suspension method can be applied to any resin component that dissolves in an organic solvent, and the shape can be easily controlled depending on the conditions at the time of solvent removal.

Hereinafter, a method for producing toner using the dissolution/suspension method will be specifically described, but the present invention is not limited thereto.

・Resin component dissolution process:
In the resin component dissolving step, a resin composition is prepared by dissolving or dispersing the binder resin and, if necessary, other components such as a colorant, wax, and silicone oil in an organic solvent.

Any organic solvent can be used as long as it can dissolve the resin component. Specific examples include toluene, xylene, chloroform, methylene chloride, and ethyl acetate. Note that toluene and ethyl acetate are preferably used from the viewpoint of promoting crystallization of the crystalline resin and ease of solvent removal.

There is no limit to the amount of the organic solvent used, but it may be used as long as it has a viscosity that allows the resin composition to be dispersed in a poor medium such as water and granulated. Specifically, the mass ratio of the resin component and, if necessary, other components such as colorant, wax, and silicone oil to the organic solvent is 10/90 to 50/50 to improve the granulation properties and toner particles described below. preferred from the viewpoint of production efficiency.

On the other hand, the colorant, wax, and silicone oil do not need to be dissolved in the organic solvent, but may be dispersed. When using a colorant, wax, and silicone oil in a dispersed state, it is preferable to disperse them using a dispersing machine such as a bead mill.

・Pelletization process:
The granulation step is a step of preparing particles of the resin composition by dispersing the obtained resin composition in an aqueous medium using a dispersant so as to have a predetermined toner particle size.

Water is mainly used as the aqueous medium.

Further, the aqueous medium preferably contains a monovalent metal salt in an amount of 1% by mass or more and 30% by mass or less. By containing the monovalent metal salt, diffusion of the organic solvent in the resin composition into the aqueous medium is suppressed, and the crystallinity of the resin component contained in the obtained toner particles is increased.

As a result, the blocking resistance of the toner tends to be good, and the particle size distribution of the toner tends to be good.

Examples of monovalent metal salts include sodium chloride, potassium chloride, lithium chloride, and potassium bromide, and among these, sodium chloride and potassium chloride are preferred.

Further, the mixing ratio (mass ratio) of the aqueous medium and the resin composition is preferably aqueous medium/resin composition = 90/10 to 50/50.

The above dispersant is not particularly limited, but cationic, anionic, and nonionic surfactants are used as organic dispersants, with anionic surfactants being preferred.

Examples include sodium alkylbenzene sulfonate, sodium α-olefin sulfonate, sodium alkyl sulfonate, and sodium alkyl diphenyl ether disulfonate. On the other hand, examples of inorganic dispersants include tricalcium phosphate, hydroxyapatite, calcium carbonate fine particles, titanium oxide fine particles, and silica fine particles.

Among these, tricalcium phosphate, which is an inorganic dispersant, is preferred. The reason for this is that there is very little adverse effect on the granulation properties and stability thereof, as well as on the properties of the resulting toner.

The amount of the dispersant added is determined according to the particle size of the granulated material, and as the amount of the dispersant added increases, the particle size becomes smaller. For this reason, the amount of the dispersant added varies depending on the desired particle size, but it is preferably used in a range of 0.1% by mass or more and 15.0% by mass or less based on the resin composition.

Further, when preparing particles of the resin composition in an aqueous medium, it is preferable to perform the preparation under high-speed shearing. Examples of devices that apply high-speed shear include various high-speed dispersers and ultrasonic dispersers.

・Solvent removal process:
In the solvent removal step, the organic solvent contained in the particles of the obtained resin composition is removed to produce toner particles. The organic solvent may be removed while stirring.

・Washing drying and classification process:
After the solvent removal step, a washing and drying step may be performed in which the toner particles are washed multiple times with water or the like, and the toner particles are filtered and dried. Further, when a dispersant such as tricalcium phosphate that dissolves under acidic conditions is used, it is preferable to wash with hydrochloric acid or the like and then wash with water. By washing, the dispersant used for granulation can be removed. After washing, toner particles can be obtained by filtering and drying and appropriately classifying.

(Suspension polymerization method)
By the suspension polymerization method, toner particles are manufactured, for example, as follows.

Polymerizable monomers in which the polymerizable monomers that produce the binder resin, colorants, wax components, polymerization initiators, etc. are uniformly dissolved or dispersed using a dispersion machine such as a homogenizer, ball mill, or ultrasonic dispersion machine. Prepare the composition. After dispersing the polymerizable monomer composition in an aqueous medium and granulating particles of the polymerizable monomer composition, polymerizing the polymerizable monomers in the particles made of the polymerizable monomer composition. to obtain toner particles.

At this time, in the polymerizable monomer composition, a dispersion in which a colorant is dispersed in a first polymerizable monomer (or some polymerizable monomers) is mixed with at least a second polymerizable monomer. It is preferable that the monomer be prepared by mixing it with the polymerizable monomer (or the remaining polymerizable monomer). That is, by sufficiently dispersing the colorant in the first polymerizable monomer and then mixing it with the second polymerizable monomer together with other toner materials, the colorant can be better dispersed. It can be present in the polymer particles in the form of

The obtained toner particles may be filtered, washed, dried, and classified according to known methods, if necessary.

(Step of adding external additives to toner particles)
A toner can be obtained by mixing the toner particles obtained by the method described above with an external additive using a mixer such as a Henschel mixer.

The weight average particle diameter (D4) of the toner is preferably 4.0 μm or more and 15.0 μm or less. Moreover, it is more preferable that it is 4.0 micrometers or more and 9.0 micrometers or less, and it is still more preferable that it is 6.0 micrometers or more and 8.0 micrometers or less.

The weight average particle diameter (D4) of the toner can be adjusted, for example, by classifying the toner particles.

<Method for measuring weight average particle diameter (D4) of toner>
The weight average particle diameter (D4) of the toner was measured using a precise particle size distribution measuring device "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter) equipped with a 100 μm aperture tube using the pore electrical resistance method, and measurement condition settings. Using the included dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter) to analyze the measurement data, measurements were taken with 25,000 effective measurement channels, and the measurement data was analyzed. and calculate.

The electrolytic aqueous solution used in the measurement can be one in which special grade sodium chloride is dissolved in ion-exchanged water to have a concentration of about 1% by mass, such as "ISOTON II" (manufactured by Beckman Coulter).

In addition, before performing measurement and analysis, configure the dedicated software as follows.

On the "Change standard measurement method (SOM) screen" of the dedicated software, set the total count in control mode to 50,000 particles, set the number of measurements to 1, and set the Kd value to "standard particle 10.0 μm" (Beckman Coulter) Set the value obtained using By pressing the threshold/noise level measurement button, the threshold and noise level are automatically set. Also, set the current to 1600 μA, the gain to 2, the electrolyte to ISOTON II, and check the aperture tube flush after measurement.

On the "Pulse to particle size conversion setting screen" of the dedicated software, set the bin interval to logarithmic particle size, the particle size bin to 256 particle size bins, and the particle size range to 2 μm or more and 60 μm or less.

The specific measurement method is as follows.
(1) Approximately 200 ml of the above electrolyte aqueous solution is placed in a 250 ml round-bottom glass beaker exclusively for Multisizer 3, set on a sample stand, and stirred with a stirrer rod counterclockwise at 24 revolutions/second. Then, use the dedicated software's ``Aperture Tube Flush'' function to remove dirt and air bubbles from inside the aperture tube.
(2) Pour about 30 ml of the above electrolytic aqueous solution into a 100 ml glass flat-bottomed beaker, and add "Contaminon N" as a dispersant (precision measurement of pH 7 consisting of nonionic surfactant, anionic surfactant, and organic builder). Approximately 0.3 ml of a diluted solution prepared by diluting a 10% by mass aqueous solution of a neutral detergent for cleaning utensils (manufactured by Wako Pure Chemical Industries, Ltd.) by 3 times by mass with ion-exchanged water is added.
(3) Two oscillators with an oscillation frequency of 50 kHz are built in with their phases shifted by 180 degrees, and are placed in the water tank of an ultrasonic dispersion device "Ultrasonic Dispersion System Tetora 150" (manufactured by Nikkaki Bios Co., Ltd.) with an electrical output of 120 W. A predetermined amount of ion-exchanged water is poured into the water tank, and approximately 2 ml of the contaminon N is added to the water tank.
(4) Set the beaker of (2) above in the beaker fixing hole of the ultrasonic disperser, and operate the ultrasonic disperser. Then, the height position of the beaker is adjusted so that the resonance state of the liquid level of the electrolytic aqueous solution in the beaker is maximized.
(5) While the electrolytic aqueous solution in the beaker of (4) is irradiated with ultrasonic waves, about 10 mg of toner is added little by little to the electrolytic aqueous solution and dispersed. Then, the ultrasonic dispersion treatment is continued for another 60 seconds. In addition, in the ultrasonic dispersion, the water temperature in the water tank is appropriately adjusted to be 10° C. or more and 40° C. or less.
(6) Using a pipette, drop the electrolytic aqueous solution (5) in which toner is dispersed into the round bottom beaker (1) placed in the sample stand, and adjust the measured concentration to about 5%. Then, the measurement is continued until the number of particles to be measured reaches 50,000.
(7) Analyze the measurement data using the dedicated software attached to the device and calculate the weight average particle diameter (D4). Note that when the dedicated software is set to graph/volume %, the "average diameter" on the analysis/volume statistics (arithmetic mean) screen is the weight average particle diameter (D4).

[Magnetic carrier]
The above toner may be mixed with a magnetic carrier and used as a two-component developer. As the magnetic carrier, a normal magnetic carrier such as ferrite or magnetite or a resin-coated carrier can be used. Further, magnetic material-dispersed resin particles in which magnetic powder is dispersed in a resin component, or porous magnetic core particles containing resin in the voids can be used.

The magnetic component used in the magnetic dispersed resin particles is selected from magnetite particles, maghemite particles, or silicon oxides, silicon hydroxides, aluminum oxides, and aluminum hydroxides. Magnetic iron oxide particle powder containing at least one type; magnetoplumbite type ferrite particle powder containing barium, strontium, or barium-strontium; spinel type containing at least one type selected from manganese, nickel, zinc, lithium, and magnesium Various magnetic iron compound particles such as ferrite particles can be used.

Furthermore, in addition to magnetic components, non-magnetic iron oxide particles such as hematite particles, non-magnetic hydrated ferric oxide particles such as goethite particles, titanium oxide particles, silica particles, and talc particles , non-magnetic inorganic compound particles such as alumina particles, barium sulfate particles, barium carbonate particles, cadmium yellow particles, calcium carbonate particles, and zinc white particles may be used in combination with magnetic iron compound particles. .

Examples of the material for the porous magnetic core particles include magnetite and ferrite. A specific example of ferrite is shown by the following general formula.
(M1 ₂ O) _x (M2O) _y (Fe ₂ O ₃ ) _Z

In the above formula, M1 is a monovalent metal, M2 is a divalent metal, and when x+y+z=1.0, x and y are respectively 0≦(x,y)≦0.8, and z is , 0.2<z<1.0)

In the formula, it is preferable to use at least one metal atom selected from the group consisting of Li, Fe, Mn, Mg, Sr, Cu, Zn, and Ca as M1 and M2. In addition, Ni, Co, Ba, Y, V, Bi, In, Ta, Zr, B, Mo, Na, Sn, Ti, Cr, Al, Si, rare earths, etc. can also be used.

The magnetic carrier preferably has magnetic carrier core particles and a resin coating layer on the surface of the magnetic carrier core particles as a resin-coated carrier. The resin coating layer covers (coats) the surface of the magnetic carrier core particles, for example. The magnetic carrier core particles are preferably porous magnetic core particles containing resin in the voids.

As the resin filling the voids of the porous magnetic core particles, either a thermoplastic resin or a thermosetting resin may be used.

Examples of thermoplastic resins to be filled include the following. Examples include novolak resin, saturated alkyl polyester resin, polyarylate, polyamide resin, acrylic resin, and the like.

Furthermore, examples of thermosetting resins include the following. Examples include phenolic resins, epoxy resins, unsaturated polyester resins, and silicone resins.

Methods for coating the surface of magnetic carrier core particles with resin include, but are not particularly limited to, coating methods such as dipping, spraying, brushing, and fluidized bed coating. Among these, the immersion method is preferred.

The amount of resin coating the surface of the magnetic carrier core particles (the amount of the resin coating layer) should be 0.1 parts by mass or more and 5.0 parts by mass or less based on 100 parts by mass of the magnetic carrier core particles. It is preferable to control the charge imparting property.

Examples of resins used for the resin coating layer include acrylic resins such as acrylic ester copolymers and methacrylic ester copolymers, styrene resins such as styrene-acrylic ester copolymers, and styrene-methacrylic ester copolymers. Acrylic resins, polytetrafluoroethylene, tetrafluoroethylene/hexafluoropropylene copolymers, monochlorotrifluoroethylene polymers, fluorine-containing resins such as polyvinylidene fluoride, silicone resins, polyester resins, polyamide resins, polyvinyl butyral, amino acrylates Examples include resin, iomonomer resin, polyphenylene sulfide resin, and the like.

These resins can be used alone or in combination. Acrylic resin is preferred.

Among these, a copolymer containing a (meth)acrylic acid ester having an alicyclic hydrocarbon group is particularly preferred from the viewpoint of charging stability. It is preferable that the resin in the resin coating layer has a monomer unit of (meth)acrylic acid ester having an alicyclic hydrocarbon group. That is, the resin of the resin coating layer contains a polymer of a monomer containing at least a (meth)acrylic acid ester having an alicyclic hydrocarbon group.

The (meth)acrylic ester having an alicyclic hydrocarbon group is preferably cyclobutyl acrylate, cyclopentyl acrylate, cyclohexyl acrylate, cycloheptyl acrylate, dicyclopentenyl acrylate, dicyclopentanyl acrylate, Examples include cyclobutyl methacrylate, cyclopentyl methacrylate, cyclohexyl methacrylate, cycloheptyl methacrylate, dicyclopentenyl methacrylate, and dicyclopentanyl methacrylate.

The alicyclic hydrocarbon group is preferably a cycloalkyl group, and the number of carbon atoms is preferably 3 or more and 10 or less, more preferably 4 or more and 8 or less. These may be used alone or in combination of two or more.

In addition, the content ratio of monomer units based on (meth)acrylic acid ester having an alicyclic hydrocarbon group in the copolymer used for the resin coating layer (copolymerization ratio based on the mass of (meth)acrylic acid ester) is preferably 5.0 mass% or more and 80.0 mass% or less, more preferably 50.0 mass% or more and 80.0 mass% or less, and 70.0 mass% or more and 80.0 mass% It is more preferable that it is the following. Within the above range, charging properties in a high temperature and high humidity environment will be good.

Furthermore, from the viewpoint of charging stability, the resin in the resin coating layer is copolymerized with a macromonomer to increase the adhesion between the magnetic carrier core particles and the resin coating layer, and to suppress local peeling of the resin coating layer. It is more preferable to include it as a component. A specific example of the macromonomer is shown in formula (B). That is, it is preferable that the resin in the resin coating layer has a monomer unit formed by a macromonomer represented by the following formula (B).

In formula (B), A is selected from the group consisting of methyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, styrene, acrylonitrile and methacrylonitrile. represents a polymer of at least one compound comprising: ^R3 is H or _CH3 .

Preferably, A is a polymer of methyl methacrylate.

In order to improve the adhesion between the magnetic carrier core particles and the resin coating layer, the weight average molecular weight of the macromonomer is preferably 3,000 or more and 10,000 or less, and preferably 4,000 or more and 7,000 or less. More preferred.

In order to improve the adhesion between the magnetic carrier core particles and the resin coating layer, the content ratio of monomer units based on macromonomers in the resin used for the resin coating layer should be 0.5% by mass or more and 30.0% by mass or less. It is preferably at least 10.0% by mass and at most 30.0% by mass, even more preferably at least 20.0% by mass and at most 25.0% by mass.

<Measurement of weight average molecular weight of macromonomer>
The weight average molecular weight is measured using gel permeation chromatography (GPC) according to the following procedure.

First, a measurement sample is prepared as follows.

The sample (coating resin was separated from the magnetic carrier and fractionated using a fractionator) and tetrahydrofuran (THF) were mixed at a concentration of 5 mg/ml, and the sample was left standing at room temperature for 24 hours. Dissolved in THF. Thereafter, the sample passed through a sample processing filter (Maishori Disc H-25-2 manufactured by Tosoh Corporation) is used as a sample for GPC.

Next, measurements are performed using a GPC measuring device (HLC-8120GPC manufactured by Tosoh Corporation) under the following measurement conditions according to the operating manual of the device.

(Measurement condition)
Equipment: High-speed GPC “HLC8120 GPC” (manufactured by Tosoh Corporation)
Column: 7 series of Shodex KF-801, 802, 803, 804, 805, 806, 807 (manufactured by Showa Denko)
Eluent: THF
Flow rate: 1.0ml/min
Oven temperature: 40.0℃
Sample injection amount: 0.10ml
In addition, in calculating the weight average molecular weight of the sample, the calibration curve was -20, F-10, F-4, F-2, F-1, A-5000, A-2500, A-1000, A-500).

[Image forming method]
The toner of the present invention can be used in known image forming methods. Specifically, the charging process involves charging the surface of the photoconductor, the electrostatic latent image forming process by which an electrostatic latent image is formed on the charged photoconductor, and the electrostatic latent image is developed with toner to form the photoconductor. A developing step for forming a toner image on the body surface, a transfer step for transferring the toner image onto a recording medium, a fixing step for fixing the toner image on the recording medium, and a cleaning blade is brought into contact with the photoreceptor to remove the toner image from the photoreceptor. It is suitably used in an image forming method that includes a cleaning step for removing residual toner on the image forming apparatus.

The contact force per unit length in the longitudinal direction between the photoreceptor and the cleaning blade is preferably 0.196 N/cm or more and 0.490 N/cm or less.

By setting the contact force to 0.196 N/cm or more, toner and external additives attached to the photoreceptor can be effectively removed. On the other hand, by setting it to 0.490 N/cm or less, it is possible to suppress the frictional heat between the photoreceptor and the cleaning blade, prevent toner fusion, and suppress the external additive from slipping through due to chatter of the cleaning blade. . As a result, toner fusion and slippage of external additives are suppressed, and ghosts caused by the external additives are effectively suppressed.

[Configuration included in the embodiment of the present invention]
The disclosure of this embodiment includes the following configurations.
(Structure 1) A toner having toner particles and an external additive on the surface of the toner particles,
The external additive has silica fine particles and titanic acid compound fine particles,
The silica fine particles are surface-treated treated silica fine particles,
In the DD/MAS measurement of the solid ²⁹ Si-NMR of the silica fine particles, there is a peak PD1 corresponding to the silicon atom represented by Si ^a in the structure represented by the above formula (1), and a peak PD1 corresponding to the silicon atom represented by the above formula (2). A peak PD2 corresponding to the silicon atom represented by Si ^b in the structure is observed, and when the area of the peak PD1 is SD1 and the area of the peak PD2 is SD2, the SD1 and the SD2 are
1.2≦(SD1+SD2)/SD1≦10.0
The filling,
The number average particle diameter of the primary particles of the titanic acid compound fine particles is 10 nm or more and 100 nm or less,
A toner characterized in that the primary particles of the titanic acid compound fine particles have an average circularity of 0.700 or more and 1.00 or less.
(Structure 2) The toner according to Structure 1, wherein the (SD1+SD2)/SD1 is 1.2 or more and 6.3 or less.
(Structure 3) In the DD/MAS measurement of the solid ²⁹ Si-NMR of the silica fine particles, a peak PQ corresponding to the silicon atom represented by Si ^c in the structure represented by the above formula (3) is observed; When the area of PQ is SQ, the SD1, the SD2 and the SQ are
(SD1+SD2)/SQ×100≧1.0
The toner according to configuration 1 or 2, which satisfies the following.
(Structure 4) Using the SD1, SD2 and SQ obtained from the solid ²⁹ Si-NMR DD/MAS measurement of the silica fine particles, the following formula:
Ca=(SD1+SD2)/SQ×100
Ca calculated from
The area SD1w of the peak PD1w corresponding to the silicon atom represented by Si ^a in the structure represented by the above formula (1) obtained from DD/MAS measurement of solid ²⁹ Si-NMR of silica fine particles after washing with hexane and the area SD2w of the peak PD2w corresponding to the silicon atom represented by Si ^b in the structure represented by the above formula (2), and the area SD2w of the peak PD2w corresponding to the silicon atom represented by Si ^c in the structure represented by the above formula (3). Using the area SQw of the corresponding peak PQw, the following formula:
Cb=(SD1w+SD2w)/SQw×100
Cb calculated from
(Ca-Cb)/Ca×100≦30
The toner according to any one of configurations 1 to 3, which satisfies the following.
(Structure 5) The toner according to any one of Structures 1 to 4, wherein the primary particles of the fine silica particles have a number average particle diameter of 5 nm or more and 500 nm or less.
(Structure 6) The toner according to any one of Structures 1 to 5, wherein the content of the silica fine particles is 0.01 parts by mass or more and 10.00 parts by mass or less, based on 100 parts by mass of the toner particles.
(Structure 7) The toner according to any one of Structures 1 to 6, wherein the titanate compound fine particles are strontium titanate particles or calcium titanate particles.
(Structure 8) The toner according to any one of Structures 1 to 7, wherein the content of the titanic acid compound fine particles is 0.05 parts by mass or more and 2.0 parts by mass or less, based on 100 parts by mass of the toner particles.
(Structure 9) The number average particle diameter A of the silica fine particles is relative to the number average particle diameter B of the titanic acid compound fine particles.
A>B
The toner according to any one of configurations 1 to 8.
(Structure 10) The silica fine particles have a moisture adsorption amount of 0.01 cm ³ /m ² or more and 0.1 cm 3 /m 2 or less per 1 m ² of BET specific surface area at a temperature of 30° C. and a relative humidity of ^{80 %} . The toner according to any one of configurations 1 to 9.
(Structure 11) In the DD/MAS measurement of the solid ²⁹ Si-NMR of the silica fine particles, a peak PQ corresponding to the silicon atom represented by Si ^c in the structure represented by the above formula (3) is observed; When the area of PQ is SQ, the SD1, the SD2 and the SQ are
(SD1+SD2)/SQ×100≧1.0
The filling,
Using the SD1, SD2 and SQ obtained from the solid ²⁹ Si-NMR DD/MAS measurement of the silica fine particles, the following formula:
Ca=(SD1+SD2)/SQ×100
Ca calculated from
The area SD1w of the peak PD1w corresponding to the silicon atom represented by Si ^a in the structure represented by the above formula (1) obtained from DD/MAS measurement of solid ²⁹ Si-NMR of silica fine particles after washing with hexane and the area SD2w of the peak PD2w corresponding to the silicon atom represented by Si ^b in the structure represented by the above formula (2), and the area SD2w of the peak PD2w corresponding to the silicon atom represented by Si ^c in the structure represented by the above formula (3). Using the area SQw of the corresponding peak PQw, the following formula:
Cb=(SD1w+SD2w)/SQw×100
Cb calculated from
(Ca-Cb)/Ca×100≦30
The filling,
Structures 1 to 10, wherein the silica fine particles have a moisture adsorption amount of 0.01 cm ³ /m ² or more and 0.1 cm ³ /m ² or less per 1 m ² of BET specific surface area at a temperature of 30° C. and a relative humidity of 80%. The toner described in any of the above.
(Structure 12) A charging step of charging the surface of a photoreceptor, an electrostatic latent image forming step of forming an electrostatic latent image on the charged photoreceptor, and a step of developing the electrostatic latent image with toner to form the electrostatic latent image on the photoreceptor. A developing step for forming a toner image on the surface, a transfer step for transferring the toner image onto a recording medium, a fixing step for fixing the toner image on the recording medium, and a cleaning blade is brought into contact with the photoreceptor, and the toner image is transferred onto the photoreceptor. An image forming method comprising: a cleaning step of removing residual toner;
The toner has toner particles and an external additive on the surface of the toner particles,
The external additive has silica fine particles and titanic acid compound fine particles,
The silica fine particles are surface-treated treated silica fine particles,
In the DD/MAS measurement of the solid ²⁹ Si-NMR of the silica fine particles, there is a peak PD1 corresponding to the silicon atom represented by Si ^a in the structure represented by the above formula (1), and a peak PD1 corresponding to the silicon atom represented by the above formula (2). A peak PD2 corresponding to the silicon atom represented by Si ^b in the structure is observed, and when the area of the peak PD1 is SD1 and the area of the peak PD2 is SD2, the SD1 and the SD2 are
1.2≦(SD1+SD2)/SD1≦10.0
The filling,
The number average particle diameter of the primary particles of the titanate compound fine particles is 10 nm or more and 100 nm or less,
An image forming method characterized in that the primary particles of the titanic acid compound fine particles have an average circularity of 0.700 or more and 1.00 or less.

The basic configuration and features of the present disclosure have been described above, and the present disclosure will be specifically described below based on examples. However, the present disclosure is not limited thereto in any way. Note that unless otherwise specified, parts and percentages are based on mass.

<Production example of binder resin 1>
・Bisphenol A ethylene oxide (2.2 mol adduct): 50.0 mol parts ・Bisphenol A propylene oxide (2.2 mol adduct): 50.0 mol parts ・Terephthalic acid: 90.0 mol parts ・Trianhydride Mellitic acid: 10.0 parts by mole 100 parts by mass of monomers constituting the above polyester unit were mixed in a 5-liter autoclave with 500 ppm of titanium tetrabutoxide.

The autoclave was equipped with a reflux condenser, a water separator, a N ₂ gas introduction tube, a thermometer, and a stirring device, and a polycondensation reaction was carried out at 230° C. while introducing N ₂ gas into the autoclave. The reaction time was adjusted to reach the desired softening point, and after the reaction was completed, the mixture was taken out of the container, cooled, and crushed to obtain a binder resin 1. Binder Resin 1 had a softening point of 130°C and a Tg of 57°C.

The softening point was measured as follows.

(Measurement of softening point)
The softening point is measured using a constant-load extrusion type capillary rheometer "Flow Characteristic Evaluation Device Flow Tester CFT-500D" (manufactured by Shimadzu Corporation) according to the manual attached to the device. In this device, a constant load is applied from the top of the measurement sample by a piston, the temperature of the measurement sample filled in the cylinder is raised and melted, and the molten measurement sample is pushed out from the die at the bottom of the cylinder. A flow curve can be obtained that shows the relationship between temperature and temperature.

The "melting temperature in the 1/2 method" described in the manual attached to the "Flow Tester CFT-500D" is defined as the softening point.

Note that the melting temperature in the 1/2 method is calculated as follows.

First, find 1/2 of the difference between the piston descent amount Smax at the time when the outflow ends and the piston descent amount Smin at the time the outflow starts (this is set as X. X = (Smax - Smin) / 2). The temperature of the flow curve when the amount of descent of the piston in the flow curve becomes the sum of X and Smin is the melting temperature in the 1/2 method.

The measurement sample was made by compression molding approximately 1.3 g of sample at 10 MPa for 60 seconds in an environment of 25° C. using a tablet molding and compressing machine (for example, NT-100H, manufactured by NP Systems), and having a diameter of approximately An 8 mm cylindrical piece is used. The measurement conditions of CFT-500D are as follows.
Test mode: Heating method Starting temperature: 50℃
Achieved temperature: 200℃
Measurement interval: 1.0℃
Temperature increase rate: 4.0℃/min
Piston cross-sectional area: 1.000cm ²
Test load (piston load): 10.0kgf/cm ² (0.9807MPa)
Preheating time: 300 seconds Die hole diameter: 1.0mm
Die length: 1.0mm

<Production example of silica fine particles 1>
500 g of fumed silica (silica fine particle base) having a number average particle diameter of 120 nm was placed in a reaction vessel, heated and stirred under nitrogen purge, and the temperature inside the reaction vessel was controlled to be 330°C.

Next, as a surface treatment agent, vapor of octamethylcyclotetrasiloxane was supplied into the reaction vessel at a rate of 8 g/min for 60 minutes. Thereafter, the silica fine particle substrate was surface-treated by heating and stirring for 120 minutes. Thereafter, the inside of the reaction vessel was purged with nitrogen to remove unreacted surface treatment agent, and then silica fine particles 1 were obtained. Table 2 shows the physical properties of the obtained silica fine particles 1.

<Production example of silica fine particles 2 to 4>
Fumed silica having the number average particle size shown in Table 1 was produced in the same manner as Silica Fine Particles 1, except that the surface treatment agent and treatment conditions were changed as shown in Table 1. Table 2 shows the physical properties of the obtained silica fine particles 2 to 4.

<Production example of silica fine particles 5>
500 g of fumed silica (silica fine particle substrate) having a number average particle diameter of 200 nm was placed in a reaction vessel, heated and stirred under nitrogen purge, and the temperature inside the reaction vessel was controlled to be 300°C.

Next, as a surface treatment agent, vapor of octamethylcyclotetrasiloxane was supplied into the reaction vessel at a rate of 8 g/min for 60 minutes. Thereafter, the silica fine particle substrate was surface-treated by heating and stirring for 120 minutes. Thereafter, the inside of the reaction vessel was purged with nitrogen to remove unreacted surface treatment agent.

Next, as a surface treatment agent, a solution prepared by diluting 15 g of polydimethylsiloxane (kinematic viscosity at 25° C.: 50 mm ² /s, average number of repeating units n=60) with 150 g of hexane was supplied by spraying. Thereafter, the silica fine particles were surface-treated by heating and stirring for 120 minutes to obtain silica fine particles 5. Table 2 shows the physical properties of the obtained silica fine particles 5.

<Production example of silica fine particles 6>
500 g of fumed silica (silica fine particle base) having a number average particle diameter of 300 nm was placed in a reaction vessel, heated and stirred under nitrogen purge, and the temperature inside the reaction vessel was controlled to be 330°C.

Next, as a surface treatment agent, a solution prepared by diluting 25 g of polydimethylsiloxane (kinematic viscosity at 25° C.: 50 mm ² /s, average number of repeating units n=60) with 250 g of hexane was supplied by spraying. Thereafter, the silica fine particle substrate was surface-treated by heating and stirring for 30 minutes to obtain silica fine particles 6. Table 2 shows the physical properties of the obtained silica fine particles 6.

<Production example of silica fine particles 7 to 10>
Fumed silica having the number average particle size shown in Table 1 was produced in the same manner as Silica Fine Particle 6, except that the surface treatment agent and treatment conditions were changed as shown in Table 1. Got 10. Table 2 shows the physical properties of the obtained silica fine particles 7 to 10.

<Production example of silica fine particles 11>
Fumed silica having the number average particle diameter as shown in Table 1 was produced in the same manner as Silica Fine Particles 1, except that the surface treatment conditions were changed as shown in Table 1. Table 2 shows the physical properties of the obtained silica fine particles 11.

In Table 1, the amount of treatment agent (parts) indicates the number of parts by mass of the surface treatment agent relative to 100 parts by mass of the silica fine particle substrate.

In Table 2, SD1 indicates the area of the peak corresponding to the silicon atom having the D1 unit structure, SD2 indicates the area of the peak corresponding to the silicon atom having the D2 unit structure, and Ca is (SD1+SD2)/SQ× 100, and the reduction rate ΔC (%) indicates the reduction rate of the amount of siloxane chains present after hexane washing compared to before hexane washing.

<Production example of titanate compound fine particles 1>
A hydrous titanium oxide slurry obtained by hydrolyzing a titanyl sulfate aqueous solution was washed with an alkaline aqueous solution until the electrical conductivity of the supernatant liquid became 50 μS/cm to reduce impurities and purify it. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 0.7 to obtain a titania sol dispersion.

A 1.3-fold molar amount of an aqueous strontium chloride solution was added to 2.2 moles (in terms of titanium oxide) of the titania sol dispersion, and the mixture was placed in a reaction vessel and replaced with nitrogen gas. Furthermore, pure water was added so that the concentration was 1.1 mol/L in terms of titanium oxide.

Next, after stirring and mixing and heating to 90° C., 440 mL of a 10N aqueous sodium hydroxide solution was added over 15 minutes while applying ultrasonic vibration, and the mixture was reacted for 20 minutes. After the reaction, pure water at 5°C was added to the slurry and the slurry was rapidly cooled to 30°C or lower, and then the supernatant liquid was removed. Further, an aqueous hydrochloric acid solution having a pH of 5.0 was added to the slurry and stirred for 1 hour to dissolve and remove strontium carbonate, followed by repeated washing with pure water.

Next, an aqueous hydrochloric acid solution with a pH of 3.0 was added to the slurry, and then 7.0% by mass of isobutyltrimethoxysilane based on the solid content of the slurry was added and stirred for 10 hours. Thereafter, it was neutralized with an aqueous sodium hydroxide solution, filtered through a Nutsche filter, and washed with pure water. The obtained cake was dried to obtain titanic acid compound fine particles 1. The physical properties are shown in Table 3.

<Production example of titanic acid compound fine particles 2>
A hydrous titanium oxide slurry obtained by hydrolyzing a titanyl sulfate aqueous solution was washed with an alkaline aqueous solution until the electrical conductivity of the supernatant liquid became 50 μS/cm to reduce impurities and purify it. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 0.7 to obtain a titania sol dispersion.

A 1.2-fold mole amount of strontium chloride aqueous solution was added to 2.0 moles (in terms of titanium oxide) of the titania sol dispersion, and the mixture was placed in a reaction vessel and replaced with nitrogen gas. Furthermore, pure water was added so that the titanium oxide concentration was 1.0 mol/L.

Next, after stirring and mixing and heating to 85° C., 800 mL of a 5N aqueous sodium hydroxide solution was added over 20 minutes while applying ultrasonic vibration, and the mixture was reacted for 20 minutes. After the reaction, pure water at 5°C was added to the slurry and the slurry was rapidly cooled to 30°C or lower, and then the supernatant liquid was removed. Further, an aqueous hydrochloric acid solution having a pH of 5.0 was added to the slurry and stirred for 1 hour to dissolve and remove strontium carbonate, followed by repeated washing with pure water.

Next, an aqueous hydrochloric acid solution with a pH of 3.0 was added to the slurry, and then 30.0% by mass of isobutyltrimethoxysilane based on the solid content of the slurry was added and stirred for 10 hours. Thereafter, it was neutralized with an aqueous sodium hydroxide solution, filtered through a Nutsche filter, and washed with pure water. The obtained cake was dried to obtain titanic acid compound fine particles 2. The physical properties are shown in Table 3.

<Production example of titanic acid compound fine particles 3>
A hydrous titanium oxide slurry obtained by hydrolyzing an aqueous titanyl sulfate solution was washed with an aqueous alkaline solution until the electrical conductivity of the supernatant became 100 μS/cm to reduce impurities and purify it. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 0.7 to obtain a titania sol dispersion.

A 1.1-fold mole amount of strontium chloride aqueous solution was added to 1.4 moles (in terms of titanium oxide) of the titania sol dispersion, and the mixture was placed in a reaction vessel and replaced with nitrogen gas. Furthermore, pure water was added so that the titanium oxide concentration was 0.7 mol/L.

Next, after stirring and mixing and heating to 80° C., 500 mL of a 20N aqueous sodium hydroxide solution was added over 5 minutes while applying ultrasonic vibration, and the mixture was reacted for 20 minutes. After the reaction slurry was slowly cooled down to 30° C. or lower over 1 hour, the supernatant liquid was removed. Further, an aqueous hydrochloric acid solution having a pH of 5.0 was added to the slurry and stirred for 1 hour to dissolve and remove strontium carbonate, followed by repeated washing with pure water.

Next, an aqueous hydrochloric acid solution with a pH of 3.0 was added to the slurry, and then 2.0% by mass of n-octyltriethoxysilane based on the solid content of the slurry was added and stirred for 10 hours. Thereafter, it was neutralized with an aqueous sodium hydroxide solution, filtered through a Nutsche filter, and washed with pure water. The obtained cake was dried to obtain titanic acid compound fine particles 3. The physical properties are shown in Table 3.

<Production example of titanic acid compound fine particles 4>
A hydrous titanium oxide slurry obtained by hydrolyzing a titanyl sulfate aqueous solution was washed with an alkaline aqueous solution until the electrical conductivity of the supernatant liquid became 50 μS/cm to reduce impurities and purify it. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 0.7 to obtain a titania sol dispersion.

A 1.2-fold mole amount of strontium chloride aqueous solution was added to 2.6 moles (in terms of titanium oxide) of the titania sol dispersion, and the mixture was placed in a reaction vessel and replaced with nitrogen gas. Furthermore, pure water was added so that the titanium oxide concentration was 1.3 mol/L.

Next, after stirring and mixing and heating to 95° C., 312 mL of a 15N aqueous sodium hydroxide solution was added over 5 minutes while applying ultrasonic vibration, and then the reaction was carried out for 20 minutes. After the reaction, pure water at 5°C was added to the slurry and the slurry was rapidly cooled to 30°C or lower, and then the supernatant liquid was removed. Further, an aqueous hydrochloric acid solution having a pH of 5.0 was added to the slurry and stirred for 1 hour to dissolve and remove strontium carbonate, followed by repeated washing with pure water.

Next, an aqueous hydrochloric acid solution with a pH of 3.0 was added to the slurry, and then 5.0% by mass of isobutyltrimethoxysilane based on the solid content of the slurry was added and stirred for 10 hours. Thereafter, it was neutralized with an aqueous sodium hydroxide solution, filtered through a Nutsche filter, and washed with pure water. The obtained cake was dried to obtain titanic acid compound fine particles 4. The physical properties are shown in Table 3.

<Production example of titanic acid compound fine particles 5>
A hydrous titanium oxide slurry obtained by hydrolyzing an aqueous titanyl sulfate solution was washed with an aqueous alkaline solution until the electrical conductivity of the supernatant became 100 μS/cm to reduce impurities and purify it. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 0.7 to obtain a titania sol dispersion.

An aqueous solution of strontium chloride in an amount of 1.0 times the mole of the titania sol dispersion was added to 0.6 moles (in terms of titanium oxide), and the mixture was placed in a reaction vessel, and the atmosphere was purged with nitrogen gas. Furthermore, pure water was added so that the titanium oxide concentration was 0.3 mol/L.

Next, after stirring and mixing and heating to 70° C., 750 mL of a 2N aqueous sodium hydroxide solution was added over 120 minutes, followed by a reaction for 20 minutes. After the reaction slurry was slowly cooled down to 30° C. or lower over 1 hour, the supernatant liquid was removed. Furthermore, the slurry was washed with pure water and dried.

Next, the inorganic fine particles were placed in a closed high-speed stirrer and stirred while purging with nitrogen. A processing agent prepared by diluting 2% by mass of dimethyl silicone oil with hexane to 6.5 times the solid content of the slurry was sprayed into the stirrer. After spraying the entire amount of the treatment agent, the temperature inside the stirrer was raised to 350° C. while stirring, and the mixture was stirred for 3 hours. While stirring, the temperature inside the stirrer was returned to room temperature and the mixture was taken out, followed by crushing with a pin mill to obtain titanate compound fine particles 5. The physical properties are shown in Table 3.

<Production example of titanic acid compound fine particles 6>
A hydrous titanium oxide slurry obtained by hydrolyzing an aqueous titanyl sulfate solution was washed with an aqueous alkaline solution until the electrical conductivity of the supernatant became 100 μS/cm to reduce impurities and purify it. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 0.7 to obtain a titania sol dispersion.

An aqueous solution of strontium chloride in an amount of 1.0 times the mole of the titania sol dispersion was added to 0.6 moles (in terms of titanium oxide), and the mixture was placed in a reaction vessel, and the atmosphere was purged with nitrogen gas. Furthermore, pure water was added so that the titanium oxide concentration was 0.3 mol/L.

Next, after stirring and mixing and heating to 70° C., 750 mL of a 2N aqueous sodium hydroxide solution was added over 120 minutes, followed by a reaction for 20 minutes. After the reaction slurry was slowly cooled down to 30° C. or lower over 1 hour, the supernatant liquid was removed. Furthermore, the slurry was washed with pure water and dried.

Next, the inorganic fine particles were placed in a closed high-speed stirrer and stirred while purging with nitrogen. A processing agent prepared by diluting 2% by mass of dimethyl silicone oil with hexane to 6.5 times the solid content of the slurry was sprayed into the stirrer. After spraying the entire amount of the treatment agent, the temperature inside the stirrer was raised to 350° C. while stirring, and the mixture was stirred for 3 hours. While stirring, the temperature inside the stirrer was returned to room temperature and the mixture was taken out to obtain titanic acid compound fine particles 6. The physical properties are shown in Table 3.

<Production example of toner 1>
・Binder resin 1 100 parts by mass ・Paraffin wax (melting point 78°C) 4 parts by mass ・C. I. Pigment Blue 15:3 4 parts by mass The above materials were premixed using a Henschel mixer (trade name: FM-10C type, manufactured by Nippon Coke Co., Ltd.), and then melt-kneaded at 160° C. using a twin-screw kneading extruder.

The obtained kneaded product was cooled, coarsely pulverized with a hammer mill, and then finely pulverized with a turbo mill.

The obtained finely pulverized product was classified using a multi-division classifier utilizing the Coanda effect to obtain toner base particles 1 having a weight average particle diameter (D4) of 6.5 μm.

(First external addition treatment)
Next, silica fine particles 1 were externally added to the obtained toner base particles 1 as a first external addition treatment as described below.

- Toner base particles 1: 100 parts by mass - Silica fine particles 1: 3.0 parts by mass The above materials were mixed using a Henschel mixer (product name: FM-10C type, manufactured by Nippon Coke Co., Ltd.) at a rotation speed of 67 s ^-1 ( 4000 rpm), the rotation time was 2 min, and the heating temperature was room temperature.

(Surface treatment of toner particles)
Thereafter, heat treatment was performed using a surface heat treatment apparatus shown in FIG. 2, so that a portion of the silica fine particles 1 was buried in the surface of the toner base particles. The operating conditions of the surface heat treatment equipment are: feed rate = 1.0 kg/hr, hot air temperature = 180°C, hot air flow rate = 1.4 m ³ /min. , cold air temperature E = 3°C, and cold air flow rate = 1.2 m ³ /min.

Next, a wind classifier using the Coanda effect ("Elbow Jet Lab EJ-L3", manufactured by Nippon Steel Mining Co., Ltd.) is used to simultaneously classify and remove fine powder and coarse powder to form toner particles with silica fine particles 1 embedded in the surface. I got 1.

(Second external addition treatment)
To the thus obtained heat-treated toner particles 1, silica fine particles were externally added as a second external addition treatment as described below.
- Toner particles 1: 100 parts by mass - Silica fine particles 1: 2.0 parts by mass - Titanic acid compound fine particles 1: 1.2 parts by mass The above materials were mixed in a Henschel mixer (product name: FM-10C type, manufactured by Nippon Coke Co., Ltd.) ), the mixture was mixed at a rotational speed of 67 s ^-1 (4000 rpm), a rotation time of 2 min, and an external addition temperature of room temperature, and then passed through an ultrasonic vibrating sieve with an opening of 54 μm to obtain Toner 1. Table 4 shows the embedding ratio of silica fine particles in the obtained Toner 1.

<Production examples of toners 2 to 11>
Toners 2 to 11 were obtained in the same manner as in the production example of Toner 1, except that the first external addition treatment, the surface treatment of toner particles, and the second external addition treatment were performed under the formulation and conditions shown in Table 4. Table 4 also shows the embedding ratio of silica fine particles in Toners 2 to 6.

<Production example of magnetic carrier core particles 1>
Process 1 (weighing/mixing process)
Fe ₂ O ₃ 68.3% by mass
MnCO ₃ 28.5% by mass
Mg(OH) ₂ 2.0% by mass
SrCO ₃ 1.2% by mass
The above ferrite raw material was weighed, 20 parts by mass of water was added to 80 parts by mass of the ferrite raw material, and then wet-mixed for 3 hours in a ball mill using zirconia having a diameter (φ) of 10 mm to prepare a slurry. The solid content concentration of the slurry was 80% by mass.

Process 2 (temporary firing process)
After drying the mixed slurry with a spray dryer (manufactured by Okawara Kakoki Co., Ltd.), it was calcined in a batch electric furnace at a temperature of 1050°C for 3.0 hours in a nitrogen atmosphere (oxygen concentration 1.0% by volume), and then calcined. Ferrite was produced.

Process 3 (Crushing process)
After the calcined ferrite was crushed to about 0.5 mm using a crusher, water was added to prepare a slurry. The solid content concentration of the slurry was set to 70% by mass. The mixture was ground for 3 hours in a wet ball mill using 1/8 inch stainless steel beads to obtain a slurry. Further, this slurry was pulverized for 4 hours in a wet bead mill using zirconia with a diameter of 1 mm to obtain a calcined ferrite slurry having a volume-based 50% particle diameter (D50) of 1.3 μm.

Process 4 (granulation process)
After adding 1.0 parts of ammonium polycarboxylate as a dispersant and 1.5 parts of polyvinyl alcohol as a binder to 100 parts by mass of the above calcined ferrite slurry, the mixture was dried into spherical particles using a spray dryer (manufactured by Okawara Kakoki Co., Ltd.). Granulated and dried. After adjusting the particle size of the obtained granules, they were heated at 700° C. for 2 hours using a rotary electric furnace to remove organic substances such as dispersants and binders.

Process 5 (baking process)
In a nitrogen atmosphere (oxygen concentration 1.0% by volume), the time from room temperature to the firing temperature (1100°C) was 2 hours, and the temperature was maintained at 1100°C for 4 hours to perform firing. Thereafter, the temperature was lowered to 60°C over 8 hours, returned to the atmosphere from the nitrogen atmosphere, and taken out at a temperature of 40°C or lower.

Process 6 (sorting process)
After crushing the aggregated particles, coarse particles are removed by sieving with a sieve with an opening of 150 μm, fine particles are removed by air classification, and low magnetic force components are removed by magnetic beneficiation to form porous magnetic core particles. I got it.

Process 7 (filling process)
100 parts by mass of porous magnetic core particles 1 were placed in a stirring container of a mixing stirrer (all-purpose stirrer NDMV type manufactured by Dalton), the temperature was maintained at 60°C, and methyl silicone oligomer: 95.0 mass was added at normal pressure. %, γ-aminopropyltrimethoxysilane: 5 parts of a filled resin consisting of 5.0% by mass were added dropwise.

After the dropwise addition was completed, stirring was continued while adjusting the time, the temperature was raised to 70° C., and the resin composition was filled into the particles of each porous magnetic core.

After cooling, the resin-filled magnetic core particles obtained were transferred to a mixer (drum mixer UD-AT type manufactured by Sugiyama Heavy Industries, Ltd.) having a spiral blade in a rotatable mixing container, and heated at 2°C/2°C under a nitrogen atmosphere. The temperature was raised to 140° C. with stirring at a temperature increase rate of 1.5 min. Thereafter, heating and stirring were continued at 140° C. for 50 minutes.

Thereafter, it was cooled to room temperature, and the resin-filled and hardened ferrite particles were taken out, and non-magnetic materials were removed using a magnetic separator. Furthermore, coarse particles were removed using a vibrating sieve to obtain resin-filled magnetic carrier core particles 1.

(Production example of coating resin)
・Cyclohexyl methacrylate monomer 26.8% by mass
・Methyl methacrylate monomer 0.2% by mass
・Methyl methacrylate macromonomer 8.4% by mass
(Macromonomer with a weight average molecular weight of 5000 having a methacryloyl group at one end)
・Toluene 31.3% by mass
・Methyl ethyl ketone 31.3% by mass
・Azobisisobutyronitrile 2.0% by mass
Of the above materials, cyclohexyl methacrylate monomer, methyl methacrylate monomer, methyl methacrylate macromonomer, toluene, and methyl ethyl ketone were placed in a four-necked separable flask equipped with a reflux condenser, thermometer, nitrogen inlet tube, and stirring device. . After nitrogen gas was introduced into the separable flask to create a sufficient nitrogen atmosphere, the mixture was heated to 80° C., azobisisobutyronitrile was added, and the mixture was refluxed for 5 hours for polymerization.

Hexane was injected into the obtained reaction product to precipitate the copolymer.

The obtained precipitate was filtered and dried under vacuum to obtain a resin. 30 parts by mass of the resin was dissolved in a mixed solvent of 40 parts by mass of toluene and 30 parts by mass of methyl ethyl ketone to obtain a resin solution (solid content concentration 30%).

(Preparation of coating resin solution)
・Resin solution (solid content concentration 30%) 33.3% by mass
・Toluene 66.4% by mass
・Carbon black (Regal330; manufactured by Cabot Corporation) 0.3% by mass
(Number average particle diameter of primary particles: 25 nm, nitrogen adsorption specific surface area: 94 m ² /g, DBP oil absorption: 75 ml/100 g)
The above materials were placed in a paint shaker and dispersed for 1 hour using zirconia beads with a diameter of 0.5 mm. The obtained dispersion liquid was filtered through a 5.0 μm membrane filter to obtain a coating resin solution.

<Manufacturing example of magnetic carrier 1>
The above coating resin solution and magnetic carrier core particles 1 were charged into a vacuum degassing type kneader maintained at room temperature (the amount of coating resin solution charged was 100 parts by mass of magnetic carrier core particles 1, and the resin component (2.5 parts by mass).

After the addition, the mixture was stirred at a rotational speed of 30 rpm for 15 minutes, and after a certain amount (80%) of the solvent had evaporated, the temperature was raised to 80° C. while mixing under reduced pressure, and the toluene was distilled off over 2 hours, followed by cooling.

The obtained magnetic carrier was separated into low-magnetic products by magnetic separation, passed through a sieve with an opening of 70 μm, and then classified with an air classifier to obtain magnetic carriers with a 50% particle size (D50) based on volume distribution of 38.2 μm. I got career 1.

[Example 1]
<Preparation of two-component developer 1>
Toner 1 and magnetic carrier 1 were added so that the toner concentration was 8.0% by mass, and the rotation time was 0.5 s ^-1 using a V-type mixer (Model V-10: Tokuju Seisakusho Co., Ltd.). Two-component developer 1 was prepared by mixing for 5 minutes.

<Evaluation>
Using the obtained two-component developer 1, the following evaluations were performed using the following image forming apparatus. Two-component developer 1 was rated A in all evaluations.

Using a modified Yanon full color copying machine imageRUNNERADVANCEC5560 as an image forming apparatus, the above two-component developer 1 was put into the cyan developing device of the image forming apparatus, and the cyan toner bottle was filled with toner 1, and the evaluation described below was carried out. went.

The modifications were that the mechanism for discharging excess magnetic carrier inside the developing device was removed, and the image forming speed was increased from 60 sheets/min to 80 sheets/min for A4 size. Modified. Further, the contact force of the cleaning blade against the photoreceptor was set to 0.245 N/cm.

As the evaluation paper, white paper (trade name: CS-814 (A4, 81.4 g/m ² ), Canon Marketing Japan) was used.

[Evaluation of photoreceptor scratches]
Using the above-mentioned image forming apparatus, 100,000 sheets of A4 horizontal 5% coverage charts were output intermittently on 5 sheets in an environment of a temperature of 10.degree. C. and a humidity of 5% RH. Thereafter, a halftone image with a printing rate of 30% was output. On the other hand, scratches on the surface of the photoreceptor were visually observed to determine the presence of image defects resulting from the scratches on the photoreceptor.
(Evaluation criteria)
A: Scratches on the photoreceptor did not appear as image defects.
B: Scratches on the photoreceptor appear as image defects.

[Evaluation of ghosts caused by external additives]
Using the above image forming apparatus, 100,000 sheets of A4 horizontal charts with a printing rate of 30% were continuously outputted in a normal temperature and low humidity environment (temperature: 23° C., humidity: 5% RH). Thereafter, 100 sheets of images were output at an image ratio of 10%, with vertical bands parallel to the paper feeding direction and areas other than the vertical bands being white. The vertical band portion is an FFh image (solid image). After passing 100 sheets, a halftone image (80h) of the entire surface was output, and ghosts caused by external additives were evaluated.

Using an X-Rite color reflection densitometer (500 series: manufactured by X-Rite), measure the image density of the halftone image in the area where vertical bands were output and the area where white background was output. Ghosts caused by external additives were evaluated based on the difference Δ between the two image densities based on the following criteria.
(Evaluation criteria)
A: Less than 0.03 B: 0.03 or more and less than 0.06 C: 0.06 or more and less than 0.11 D: 0.11 or more

[Toner fusion]
Using the image forming apparatus described above, 100,000 sheets of A4 horizontal charts with a printing rate of 30% were continuously outputted in a high temperature and high humidity environment (temperature: 30° C., humidity: 80% RH). Thereafter, an FFh image (solid image) was formed on the entire surface of A4 evaluation paper, and the number of white spots appearing on the solid image was visually evaluated.
(Evaluation criteria)
A: 0 pieces B: 1 piece or more and less than 5 pieces C: 6 pieces or more and less than 10 pieces D: 10 pieces or more

[Examples 2 to 7, Comparative Examples 1 to 4]
<Preparation and evaluation of two-component developers 2 to 11>
Two-component developers 2-11 were prepared in the same manner as two-component developer 1 except that toner 1 was replaced with toners 2-11.

Next, evaluation was performed in the same manner as in Example 1, except that two-component developers 2 to 11 were used. The evaluation results are shown in Table 5.

Claims (12)

A toner comprising toner particles and an external additive on the surface of the toner particles,
The external additive has silica fine particles and titanic acid compound fine particles,
The silica fine particles are surface-treated treated silica fine particles,
In the DD/MAS measurement of the solid ²⁹ Si-NMR of the silica fine particles, there is a peak PD1 corresponding to the silicon atom represented by Si ^a in the structure represented by the following formula (1), and a peak PD1 corresponding to the silicon atom represented by the following formula (2). A peak PD2 corresponding to the silicon atom represented by Si ^b in the structure is observed, and when the area of the peak PD1 is SD1 and the area of the peak PD2 is SD2, the SD1 and the SD2 are
1.2≦(SD1+SD2)/SD1≦10.0
The filling,
The number average particle diameter of the primary particles of the titanic acid compound fine particles is 10 nm or more and 100 nm or less,
A toner characterized in that the primary particles of the titanic acid compound fine particles have an average circularity of 0.700 or more and 1.00 or less.

(In the formula, each R independently represents a hydrogen atom, a methyl group, or an ethyl group.) The toner according to claim 1, wherein the (SD1+SD2)/SD1 is 1.2 or more and 6.3 or less. In the DD/MAS measurement of the solid ²⁹ Si-NMR of the silica fine particles, a peak PQ corresponding to the silicon atom represented by Si ^c in the structure represented by the following formula (3) was observed, and the area of the peak PQ was When SQ, the SD1, the SD2, and the SQ are
(SD1+SD2)/SQ×100≧1.0
The toner according to claim 1 or 2, which satisfies the following.

Using the SD1, SD2, and SQ obtained from the solid ²⁹ Si-NMR DD/MAS measurement of the silica fine particles, the following formula:
Ca=(SD1+SD2)/SQ×100
Ca calculated from
The area SD1w of the peak PD1w corresponding to the silicon atom represented by Si ^a in the structure represented by the above formula (1) obtained from DD/MAS measurement of solid ²⁹ Si-NMR of silica fine particles after washing with hexane and the area SD2w of the peak PD2w corresponding to the silicon atom represented by Si ^b in the structure represented by the above formula (2), and the area SD2w of the peak PD2w corresponding to the silicon atom represented by Si ^c in the structure represented by the above formula (3). Using the area SQw of the corresponding peak PQw, the following formula:
Cb=(SD1w+SD2w)/SQw×100
Cb calculated from
(Ca-Cb)/Ca×100≦30
The toner according to claim 3, which satisfies the following. The toner according to claim 1 or 2, wherein the number average particle diameter of the primary particles of the silica fine particles is 5 nm or more and 500 nm or less. The toner according to claim 1 or 2, wherein the content of the silica fine particles is 0.01 parts by mass or more and 10.00 parts by mass or less based on 100 parts by mass of the toner particles. 3. The toner according to claim 1, wherein the titanate compound fine particles are strontium titanate particles or calcium titanate particles. The toner according to claim 1 or 2, wherein the content of the titanic acid compound fine particles is 0.05 parts by mass or more and 2.0 parts by mass or less, based on 100 parts by mass of the toner particles. The number average particle size A of the silica fine particles is equal to the number average particle size B of the titanic acid compound fine particles,
A>B
The toner according to claim 1 or 2. 2. The silica fine particles have a water adsorption amount of 0.01 cm 3 /m ² or more and 0.1 cm ³ /m ^{2 or less per m 2 of} BET specific surface area at a temperature of 30 ^° C. and a relative humidity of 80%. 2. The toner described in 2. In the DD/MAS measurement of the solid ²⁹ Si-NMR of the silica fine particles, a peak PQ corresponding to the silicon atom represented by Si ^c in the structure represented by the following formula (3) was observed, and the area of the peak PQ was When SQ, the SD1, the SD2, and the SQ are
(SD1+SD2)/SQ×100≧1.0
The filling,
Using the SD1, SD2 and SQ obtained from the solid ²⁹ Si-NMR DD/MAS measurement of the silica fine particles, the following formula:
Ca=(SD1+SD2)/SQ×100
Ca calculated from
The area SD1w of the peak PD1w corresponding to the silicon atom represented by Si ^a in the structure represented by the above formula (1) obtained from DD/MAS measurement of solid ²⁹ Si-NMR of silica fine particles after washing with hexane and the area SD2w of the peak PD2w corresponding to the silicon atom represented by Si ^b in the structure represented by formula (2), and the area SD2w of the peak PD2w corresponding to the silicon atom represented by Si ^c in the structure represented by formula (3). Using the area SQw of the corresponding peak PQw, the following formula:
Cb=(SD1w+SD2w)/SQw×100
Cb calculated from
(Ca-Cb)/Ca×100≦30
The filling,
2. The silica fine particles have a moisture adsorption amount of 0.01 cm 3 /m ² or more and 0.1 cm ³ /m ^{2 or less per m 2 of} BET specific surface area at a temperature of 30 ^° C. and a relative humidity of 80%. 2. The toner described in 2.

A charging step of charging the surface of the photoreceptor, an electrostatic latent image forming step of forming an electrostatic latent image on the charged photoreceptor, and a toner image on the surface of the photoreceptor by developing the electrostatic latent image with toner. A developing process to form a toner image, a transfer process to transfer the toner image to a recording medium, a fixing process to fix the toner image on the recording medium, and a cleaning blade is brought into contact with the photoconductor to remove the residual toner on the photoconductor. In an image forming method comprising a cleaning step of removing,
The toner has toner particles and an external additive on the surface of the toner particles,
The external additive has silica fine particles and titanic acid compound fine particles,
The silica fine particles are surface-treated treated silica fine particles,
In the DD/MAS measurement of the solid ²⁹ Si-NMR of the silica fine particles, there is a peak PD1 corresponding to the silicon atom represented by Si ^a in the structure represented by the following formula (1), and a peak PD1 corresponding to the silicon atom represented by the following formula (2). A peak PD2 corresponding to the silicon atom represented by Si ^b in the structure is observed, and when the area of the peak PD1 is SD1 and the area of the peak PD2 is SD2, the SD1 and the SD2 are
1.2≦(SD1+SD2)/SD1≦10.0
The filling,
The number average particle diameter of the primary particles of the titanic acid compound fine particles is 10 nm or more and 100 nm or less,
An image forming method characterized in that the primary particles of the titanic acid compound fine particles have an average circularity of 0.700 or more and 1.00 or less.

(In the formula, each R independently represents a hydrogen atom, a methyl group, or an ethyl group.)

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