JP2000258950A - Electrostatic charge image developing toner and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electrostatic charge image developing toner which has small environmental dependency of electrostatic charge, gives stable image quality over a long period of time, undergoes a slight change of electrostatic charge in toner in transfer, attains stable high transfer efficiency even in plural transfer or multiple transfer, hardly contaminates an electrifying member such as a carrier and does not cause filming on an electrostatic latent image support. SOLUTION: The electrostatic charge image developing toner contains fine titanium dioxide particles having 1×1010-1×1014 Ωcm volume resistivity. When the calculated covering rate of the surfaces of the toner matrix particles with the fine titanium dioxide particles is represented by C0 and the measured covering rate by C, the sticking rate (C/C0) of the fine titanium dioxide particles to the surfaces of the toner matrix particles is >=0.3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic image developing toner for forming a monochromatic or multicolor image and an image forming method.

[0002]

2. Description of the Related Art In recent years, with the rapid spread of PCs and networks in offices, the market for copiers and printers, which has been mainly composed of monochromes, is changing to full color.
Along with this, market demands for electrophotographic copying machines and printers, which were conventionally advantageous in terms of image quality and speed, are increasing. In particular, recent market demands include not only high image quality and high reliability but also ecological measures such as energy saving, resource saving and recycling, in addition to small size, light weight, low price and high speed. ing. To cope with this, improvements and new developments of an image forming method and a developer used therein have been made.

An electrophotographic image forming apparatus generally includes a charging step of uniformly charging the surface of an electrostatic latent image carrier, an exposure step of exposing the surface of the latent image carrier to form an electrostatic latent image, and a developer carrier. A developing step of developing a latent image on the surface of the electrostatic latent image carrier using a developer layer formed on the surface to obtain a toner image, a transferring step of transferring the toner image onto a transfer material, and the transfer material The image forming apparatus includes a fixing step of fixing the upper toner image, and a cleaning step of removing toner remaining on the surface of the electrostatic latent image carrier in the transfer step. The basic properties required of the toner for these processes include an appropriate amount of toner charge in the development process, charge maintenance, environmental stability, good transfer performance in the transfer process, low-temperature fixability in the fixing process, and anti-offset. Many properties are required, such as cleaning properties, cleaning performance in a cleaning step, and stain resistance. In particular, with the recent promotion of high image quality, high speed, and colorization, the above characteristics are required to be more and more complicated.

For example, in the above transfer step, in order to make it easier to perform registration when forming a color image, a toner image on the surface of the electrostatic latent image carrier is transferred using an intermediate transfer member, and then transferred to a transfer target material. Indirect transfer type image forming apparatuses for transferring images can realize higher speed and higher image quality, and are becoming the mainstream of full-color copying machines and printers in recent years. However, such an indirect transfer type image forming apparatus increases the number of times of transfer of the toner, so that a higher and accurate transfer performance is required for higher image quality, and more stable charging performance and transfer efficiency for the toner. There are demands for additives for improving the toner quality, techniques for controlling toner shape and surface structure, and the like.

[0005] Further, regarding the cleaning process, not only from the viewpoint of miniaturization and cost reduction of the apparatus, but also energy saving and
From the viewpoint of ecology such as resource saving and waste reduction,
It is important to reduce the amount of transfer residual toner and reduce the size of the cleaning device. Particularly, in a full-color image forming apparatus using three color toners of yellow, magenta, and cyan, or four color toners of black, transfer residual toner is a serious problem.

In order to avoid such a new problem in the transfer / cleaning step, it is important to minimize the amount of the residual toner, and for that purpose, it is necessary to increase the transfer efficiency of the toner. In order to increase the transfer efficiency, it is important to transfer the toner base particles directly adhered to the electrostatic latent image carrier, and for that purpose, the adhesion between the toner and the electrostatic latent image carrier is reduced. It is effective.
Examples of such a method include, for example, JP-A-2-1870, JP-A-2-81053, and JP-A-2-118.
671, JP-A-118672, JP-A-2-
As described in JP-A-157766, the developer contains releasable fine particles such as silica, so that the fine particles are interposed between the toner and the electrostatic latent image carrier so that the toner and the electrostatic latent image A method has been proposed in which the transfer force of the toner is increased by reducing the adhesive force of the carrier. However, in order to obtain high transfer efficiency in these methods, it is necessary to set a high coverage of the toner surface with the fine particles. Attachment and filming of fine particles to the body, etc.
Problems such as fixing failure are likely to occur. In particular, since the silica particles are highly dependent on the environment, the transfer efficiency is improved, but problems such as uneven image density in a low-temperature and low-humidity environment and fog in a high-temperature and high-humidity environment are likely to occur.

On the other hand, as a method for improving the environment dependency of toner charging, a method is known in which inorganic particles such as titanium oxide having relatively low resistance and good charge exchange properties are added to silica particles. When inorganic fine particles are used, the charge distribution on the transfer body is likely to change due to charge injection in the transfer electric field, poor transfer during secondary transfer when using an intermediate transfer body, and reverse polarity toner during multiple transfer of full-color toner. Is likely to occur. In order to avoid this problem, it is possible to control the resistance of inorganic fine particles having a low resistance such as titanium oxide to a relatively high level by surface treatment with a silane coupling agent or the like. In addition, the dispersibility on the toner surface is deteriorated, and the function of enhancing the original charge exchange property is deteriorated. In addition, the toner fluidity is deteriorated, charged members such as carriers are contaminated by loose aggregated particles, and the electrostatic latent image is carried. Problems such as filming on the body are likely to occur.

[0008] As described above, there are still many problems in providing sufficient toner characteristics in response to the recent demand for high quality, high speed, high reliability, and ecological hardware. is there.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. That is, a first object of the present invention is to provide a toner for developing an electrostatic image and an image forming method capable of obtaining stable image quality over a long period of time with a small environmental dependency of charging. A second object of the present invention is to provide a toner for developing an electrostatic image and an image forming method capable of obtaining a stable and high transfer efficiency even in multiple transfer and multiple transfer with little change in charge in toner transfer. A third object of the present invention is to
An object of the present invention is to provide a toner for developing an electrostatic charge image and an image forming method, in which contamination of a charging member such as a carrier is small and filming does not occur on an electrostatic latent image carrier.

[0010]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the above objects can be achieved by the following invention. That is, the present invention

<1> A toner for developing an electrostatic image containing toner base particles containing at least a binder resin and a colorant and titanium oxide fine particles, wherein the titanium oxide fine particles have a volume resistivity of 1 × 10 ¹⁰ １1 × 10 ¹⁴ Ωcm, and when the calculated coverage of the titanium oxide fine particles on the surface of the toner base particles is C ₀ and the measured coverage is C, the surface of the toner base particles of the titanium oxide fine particles is Adhesion rate (C / C
₀ ) is 0.3 or more.

<2> a charging step for uniformly charging the surface of the electrostatic latent image carrier, an exposure step for exposing the surface of the electrostatic latent image carrier to form an electrostatic latent image, and an electrostatic latent image carrier Developing the electrostatic latent image formed on the surface using an electrostatic charge image developer to form a toner image; transferring the toner image onto a transfer material; and transferring the toner image onto the transfer material. A fixing step of fixing the toner image of (1), wherein the electrostatic image developer contains the electrostatic image developing toner according to <1>. Is the way.

<3> Charging means for uniformly charging the surface of the electrostatic latent image carrier, exposure means for exposing the surface of the electrostatic latent image carrier to form an electrostatic latent image, and electrostatic latent image carrier Developing means for developing the electrostatic latent image formed on the surface using an electrostatic charge image developer to form a toner image; transfer means for transferring the toner image onto a transfer material; An image forming apparatus comprising: a fixing unit for fixing the toner image according to (1), wherein the electrostatic image developer contains the electrostatic image developing toner according to <1>. Device.

[0014]

Embodiments of the present invention will be described below in detail. The toner for developing an electrostatic image of the present invention (hereinafter may be simply referred to as toner) is a toner for developing an electrostatic image containing at least toner base particles containing a binder resin and a colorant and fine particles of titanium oxide. .

The titanium oxide fine particles will be described. For the titanium oxide fine particles, the calculated coverage of the titanium oxide fine particles on the surface of the toner base particles is C ₀ , and the measured coverage is C _0.
When the adhesion ratio (C / C ₀ ) of the titanium oxide fine particles to the surface of the toner base particles is 0.3 or more, preferably 0.4 or more, more preferably 0.5 or more, It is contained.

The calculated coverage C ₀ of the fine particles of titanium oxide on the surface of the toner base particles is 1 based on the volume average of the toner base particles.
Dt (m), average primary particle diameter of titanium oxide fine particles is da (m), specific gravity of toner is ρt, specific gravity of titanium oxide fine particles is ρa, toner weight is Wt (kg), titanium oxide fine particles Can be calculated by the following equation (1-a), where the amount of addition is Wa (kg).

Equation (1-a) C ₀ = √3 / 2π × ρt / ρa × dt / da × Wa / W
t × 100 (%)

The actually measured coverage C of the surface of the toner base particles by the titanium oxide fine particles was determined by an X-ray photoelectron spectrometer (XPS).
("JPS-9000MX": manufactured by JEOL Ltd.), the signal intensity of titanium atoms derived from titanium oxide fine particles was measured for toner toner particles only, titanium oxide fine particles only, and toner containing titanium oxide fine particles. , Can be calculated by the following equation (1-b).

Formula (1-b) C = (z−x) / (y−x) × 100 (%) (in the formula (1-b), x is derived from titanium oxide fine particles consisting only of toner base particles.) The signal intensity of a titanium atom is shown.
y indicates the signal intensity of titanium atoms derived from titanium oxide fine particles of only titanium oxide fine particles. z indicates the signal intensity of titanium atoms derived from the titanium oxide fine particles in the toner containing the titanium oxide fine particles. )

If the adhesion ratio (C / C ₀ ) of the titanium oxide fine particles to the surface of the toner base particles is less than 0.3, the function of the titanium oxide fine particles to enhance the charge exchange property of the toner is reduced. Causes broadening of the surface, lowering of the charging speed, and deterioration of the environment dependency, which may cause problems such as fogging in a high-temperature and high-humidity environment, density reduction in a low-temperature and low-humidity environment, and density unevenness. Also, since the aggregated fine particles released from the toner increase, they adhere to and film on the electrostatic latent image carrier, causing a problem of white streaks and black streaks on the image, and further, a reduction in charge due to contamination of a charging member such as a carrier. May cause

The volume resistivity of the titanium oxide fine particles is 1 × 1
0^Ten~ 1 × 10¹⁴Ωcm, preferably 1 × 10¹¹
~ 1 × 10¹⁴Ωcm, more preferably 1 × 10¹¹~ 1 ×
10 ¹³Ωcm.

The volume resistivity of the titanium oxide fine particles can be measured by the following method. Electrometer (trade name: KEYTHLEY610C, manufactured by KEYTHLEY) and high voltage power supply (trade name: FLUKE415B, FKU)
A titanium oxide fine particle is formed on a lower electrode plate of a pair of 20 cm ² circular electrode plates (made of steel) of a measuring jig connected to a measuring electrode (made by KE Co., Ltd.) so as to form a flat layer having a thickness of about 1 to 2 mm. Then, after the upper electrode plate was placed on the titanium oxide fine particles, the thickness of the fine particle layer was measured with a weight of 4 kg placed on the upper electrode plate in order to eliminate voids in the fine particles. Next, a voltage of 1000 V was applied to both electrode plates to measure a current value,
The volume resistivity can be calculated based on the following equation (2). Equation (2) Volume resistivity (ρ) = V × S ÷ (A−A ₀ ) ÷ d (Ωc
m) (In the formula (2), V is an applied voltage of 1000 (V), S is an electrode plate area of 20 (cm ² ), A is a measured current value (A), and A ₀ is an initial current value at an applied voltage of 0. (A), d is the particle layer thickness (c
m). )

The volume resistivity of the titanium oxide fine particles is 1 × 1
If it is less than 0 ¹⁰ Ωcm, the charge exchange property of the toner is improved, but at the time of toner transfer, the charge of the toner after transfer is deteriorated due to charge injection by a transfer electric field, and the secondary transfer when an intermediate transfer member is used. In some cases, defective transfer may occur during multiple transfer of full-color toner. When the volume resistivity is larger than 1 × 10 ¹⁴ Ωcm, the function of enhancing the intrinsic charge exchange property of the titanium oxide fine particles is reduced, causing a broadening of the charge distribution, a reduction in the charging speed, and a deterioration in the environmental dependency. Problems such as fogging under an environment, density reduction under a low-temperature and low-humidity environment, and density unevenness may occur.

It is preferable that the surface of the titanium oxide fine particles is subjected to a hydrophobic treatment with a silane compound, silicone oil or the like in order to optimize the volume resistivity and the cohesiveness.

As the silane compound, the volume resistivity of the titanium oxide fine particles is 1 × 10 ¹⁰ to 1 × 10 ¹⁴ Ωcm, and the adhesion ratio C / C _{0 of the} titanium oxide fine particles to the surface of the toner base particles satisfies 0.3 or more. Any one can be used as long as it is, and examples thereof include an alkylalkoxysilane represented by the following structural formula (A) and a fluorinated alkylalkoxysilane represented by the following structural formula (B).

The structural formula _{(A) C a H 2a +} 1 -Si- (OC b H 2b + 1) 3 Formula _{(B) C n F 2n +} 1 CH 2 CH 2 Si (CH 3) p X 3- _P

In the structural formula (A), a represents a positive integer, b
Represents an integer of 1 to 3. In the structural formula (B), X represents a hydrolyzable group, n represents a positive integer, and p represents 0 or 1.
Examples of the hydrolyzable group include a halogen atom (for example, chloro and the like) and an alkoxy group having 1 to 4 carbon atoms (for example, a methoxy group and an ethoxy group). Of these, a methoxy group and an ethoxy group are preferable. )

In the structural formulas (A) and (B), a and n are
From the viewpoints of volume resistivity and cohesiveness, it is usually preferable to show an integer of 5 to 20, more preferably an integer of 7 to 20, and even more preferably an integer of 10 to 18. If the alkyl group of the silane compound is too short, the volume resistivity tends to be low. On the other hand, if the length of the silane compound is too long, the surface of the fine particles may not be able to be subjected to a uniform hydrophobization treatment, but also the tendency to cause fine particle aggregation. Therefore, neither is preferable. The silane compound has a particularly high cohesiveness, so that even when the conditions for mixing into the toner are usually increased using a mixer such as a V blender or a Henschel mixer, the fine particles are less likely to be loosened. There is a possibility that the adhesion rate of the titanium oxide fine particles does not increase.

The amount of the silane compound to be treated is generally preferably about 5 to 30 parts by weight, more preferably 10 to 20 parts by weight, per 100 parts by weight of the titanium oxide fine particles. If the treatment amount is small, the volume resistivity tends to be low. On the other hand, if the treatment amount is too large, not only the volume resistivity becomes too high, but also the cohesion of the fine particles tends to become strong, and both are not preferable.

Examples of the silicone oil include dimethyl silicone oil, methylphenyl silicone oil, alkyl-modified silicone oil, fluorine-modified silicone oil, and amino-modified silicone oil.

The treatment amount of the silicone oil is usually preferably about 5 to 30 parts by weight, more preferably 10 to 20 parts by weight, per 100 parts by weight of the titanium oxide fine particles. If the treatment amount is small, the volume resistivity tends to be low. On the other hand, if the treatment amount is too large, not only the volume resistivity becomes too high, but also the cohesion of the fine particles tends to become strong, and both are not preferable.

The hydrophobizing treatment of the titanium oxide fine particles is usually performed in an organic solvent such as alcohol or toluene by a wet process. However, in order to loosen the aggregation of the titanium oxide fine particles and to improve the dispersibility on the surface of the toner base particles, the hydrophobic treatment is performed. During the hydrophobization treatment, it is preferable to sufficiently perform wet pulverization using a ball mill, a sand grinder, or the like, and it is particularly preferable to dry-pulverize with a jet mill or the like after drying after the hydrophobization treatment.

Examples of the titanium oxide fine particles include rutile type, anatase type and amorphous titania.

The titanium oxide fine particles have an average primary particle size of 10
It is preferable that the fine particles have a size of 50 nm to 50 nm. If the average primary particle diameter is less than 10 nm, the agglomeration of the fine particles may be significantly increased, and the dispersion in the toner tends to be difficult. On the other hand, when the average primary particle diameter exceeds 50 nm, the fluidity of the toner is low, and there is a possibility that the transportability in the developing device and the mixing with the carrier may be reduced. The average primary particle size of titanium oxide is
SEM (acceleration voltage 5)
(kv, 30000 times), the primary particle diameter can be determined and calculated.

In the titanium oxide fine particles, the ratio (a2 / a1) of the average primary particle diameter (a1) and the average aggregated particle diameter (a2) of the titanium oxide fine particles adhered to the surface of the toner base particles may be less than 5. Preferred, more preferably less than 4,
More preferably, it is less than 3. When the ratio is 5 or more, there is a possibility that the aggregated particles of titanium oxide increase the contact area with the electrostatic latent image carrier, or reduce the transfer rate because a low-charged toner is produced. The average aggregated particle diameter of titanium oxide can be calculated in the same manner as the average primary particle diameter.

The titanium oxide fine particles include titanium oxide fine particles,
And varies depending on the particle size of the toner base particles, it is preferred to be added to a 10-90% at a coverage rate C ₀ on the calculation of the toner base particle surfaces by titanium oxide particles,
More preferably, it is added so as to be 10 to 70%. If the coverage C ₀ is less than 10%, the effect of improving the charge exchangeability of the toner may be insufficient, and the broadening of the charge distribution and the environmental dependency tend to increase. On the other hand, when the coverage C ₀ exceeds 90%, the released fine particles and toner surface fine particles easily migrate to a charging member such as a carrier or an electrostatic latent image carrier, and are likely to cause poor charging or filming. In the case of color toner,
If the addition amount of the titanium oxide fine particles exceeds 3.0 parts by weight based on 100 parts by weight of the toner base particles, the OHP transmittance of a color image tends to decrease, which is not preferable.

The toner base particles will be described. The toner base particles contain at least a binder resin and a colorant. As the binder resin, polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene butadiene copolymer, styrene-maleic anhydride copolymer, polyethylene, Known materials such as polypropylene, polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, and paraffin wax are exemplified, and among them, styrene-acryl copolymer and polyester are preferable.

Examples of the coloring agent include carbon black (eg, furnace black, channel black, acetylene black, thermal black, etc.), inorganic pigments (eg, red, blue, titanium oxide, etc.) and azo pigments (eg, fast yellow, disazo yellow, pyrazolone). Red, chelate red, brilliant carmine, parabrown, etc.), phthalocyanine pigments (eg, copper phthalocyanine, metal-free phthalocyanine, etc.), condensed polycyclic pigments (eg, flavanthrone yellow, dibromoanthrone orange, perylene red, quinacridone red, dioxazine violet) And the like, known inorganic or organic pigments. In addition, as a coloring agent, aniline blue, calcoil blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow,
Methylene blue chloride, malachite green oxalate, lamp black, rose bengal, C.I. I. Pi
gment Red 48: 1, C.I. I. Pigmen
t Red 122, C.I. I. Pigment Red
57: 1, C.I. I. Pigment Yellow 9
7, C.I. I. Pigment Yellow 12,
C. I. Pigment Yellow 17, C.I.
I. Pigment Yellow 180, C.I. I.
Pigment Blue 15: 1, C.I. I. Pig
Ment Blue 15: 3. The colorant is added in an amount of about 1 to 50 parts by weight based on 100 parts by weight of the binder resin, and preferably 2 to 20 parts by weight.

The toner base particles have a volume average particle size of 3 to 1
0 μm is preferable, 4 to 10 μm is more preferable, and 5 to 8 μm is more preferable. Volume average particle size is 3μ
If it is less than m, the fluidity is remarkably deteriorated, so that charging of the toner and uniform formation of the developer layer cannot be performed well, which is likely to cause fog and dirt. On the other hand, if the thickness is 10 μm or more, the resolution is reduced and high image quality cannot be obtained.

The degree of sphericity of the toner base particles is preferably 130 or less, and more preferably 120 or less, from the viewpoint of transfer efficiency.
If the degree of spheroidization exceeds 130, the contact area between the electrostatic latent image carrier and the toner increases, so that the transferability may be reduced. By making the toner base particles spherical, the fluidity, chargeability and transferability of the toner can be improved.

The degree of sphericity of the toner base particles is obtained by calculating the maximum length of the toner base particles calculated from the two-dimensional projected image of the toner base particles input from the optical microscope by the image analyzer, as ML, and calculating the projected area of the toner base particles. When A is set, it is calculated by the following equation (3).

Equation (3) Sphericity = 100 × π × (ML) ² / (4 × A)

As a method for producing toner base particles having a degree of sphericity of 130 or less, an oil component obtained by dissolving and dispersing a binder resin, a colorant, and other additives in an organic solvent is suspended in an aqueous medium. Suspended dispersion method, after which the solvent is removed, the kneaded material is kneaded in a state where the kneaded material is melted by heating the kneaded material in an immiscible medium, kneading the binder resin, colorant, and other additives. In the case where a wax is contained in the toner, a submerged drying method that is not heated during the formation of particles is preferable. Further, any method such as a method of heating and spheroidizing particles obtained by a suspension polymerization method or a kneading and pulverizing method may be used. In the aqueous medium, an inorganic dispersion stabilizer may be added, as the inorganic dispersion stabilizer, tricalcium phosphate, hydroxyapatite, calcium carbonate,
Titanium oxide, aluminum hydroxide, magnesium hydroxide, barium sulfate, silicon oxide and the like can be mentioned, among which calcium carbonate is preferable. The amount of the inorganic dispersant is preferably 1 to 30 parts by weight based on 100 parts by weight of the aqueous medium.
Further, the average particle diameter of the particles of the inorganic dispersant is preferably 1 μm or less.

The toner of the present invention may contain a release agent. This release agent is used for the purpose of improving gloss and offset properties, or for the purpose of eliminating the need for oil supply to the fixing device and achieving space saving. Examples of the release agent include paraffin wax, oxidized paraffin wax, and microcrystalline wax. Mineral wax such as petroleum wax and montan wax; animal and plant wax such as beeswax and carnauba wax; and synthetic wax such as polyolefin wax, oxidized polyolefin wax and Fischer-Tropsch wax. The melting point of the release agent is 40
C. to 150.degree. C. are preferred, and 50.degree. These release agents are used alone or in combination of two or more.

The toner of the present invention may contain a charge controlling agent. This charge control agent is used for the purpose of assisting the charge of the toner. When used as a negatively charged toner, chromium, azo complex dyes such as iron, chromium of salicylic acid, zinc, aluminum, complex compounds such as boron and the like, when used as a positively charged toner, quaternary ammonium salts and the like, The charge control agent is a metal salt of benzoic acid, a metal salt of salicylic acid, a metal salt of alkyl salicylic acid, a metal salt of catechol, a metal-containing bisazo dye, tetraphenyl borate, which is used in a powder toner for xerography. Compounds selected from the group consisting of derivatives, quaternary ammonium salts, and alkylpyridinium salts, polar group-containing resin-type charge control agents, and suitably combined ones of these can also be preferably used. These charge control agents are used alone or in combination of two or more. The addition amount of these charge control agents is generally in the range of 10% by weight or less based on the solid content of the toner.

The toner of the present invention contains conductive powder for the purpose of adding other fluidizing agent fine particles for the purpose of imparting appropriate fluidity and chargeability to the developer, improving the charge exchange property, improving the cleaning property, and improving the photosensitive property. An additive such as a lubricant or an abrasive for the purpose of preventing black spots, white spots, white spots, comets, filming, etc. due to adhesion of toner, external additives, and talc to the body may be used. Fluidizing agent fine particles used, as additives, hydrophobic silica, inorganic fine particles such as alumina, organic fine particles such as fatty acids or their derivatives and metal salts, fluorine resin, resin fine particles such as acrylic resin or styrene resin,
Cerium oxide, magnetite and the like can be mentioned, and these can be used alone or in combination. In particular, it is preferable to use hydrophobic silica in combination in order to improve the fluidity, chargeability and transferability of the toner.

The inorganic fine particles (additives) other than the above-mentioned titanium oxide fine particles have a primary particle diameter of at least 50 n.
It is preferable to include inorganic fine particles of m to 300 nm.
The toner of the present invention can maintain good transferability in a long-term use by making inorganic fine particles having a primary particle diameter of 50 nm to 300 nm be present in addition to spheroidizing the toner base particles. Among the inorganic fine particles, silicon oxide fine particles having a low refractive index are particularly preferable from the viewpoint of the transparency of the OHP fixed image of the toner. As the silicon oxide fine particles, those subjected to hydrophobic treatment with a silane coupling agent, silicone oil or the like are particularly preferable. As a method for adding the inorganic fine particles to the surface of the toner base particles, any method may be used as long as the adhesion ratio (C / C ₀ ) of the titanium oxide fine particles to the toner base particles satisfies 0.3 or more. After drying
Using a mixer such as a V blender or a Henschel mixer, the toner may be adhered to the toner surface in a dry manner, or fine particles may be dispersed in water or an aqueous liquid such as water / alcohol, and then added to the toner in a slurry state. Alternatively, it may be dried and adhered to the toner surface. Alternatively, the slurry may be dried while spraying the slurry on the dry powder.

The toner base particles of the present invention can be produced by any known method. For example, kneading and pulverizing methods, ie, after preliminarily mixing a binder resin, a colorant and a charge controlling agent, are melt-kneaded by a kneading machine. And then pulverize and classify after cooling,
Polymerized toners such as suspension polymerization and emulsion polymerization can be used. To dry the toner of the present invention, a through-air drying device,
A spray drying device, a rotary drying device, a flash drying device, a fluidized bed drying device, a heat transfer heating type drying device, a freeze drying device and the like are known, and any of them can be used.

The toner of the present invention can be suitably used as a toner in an electrostatic image developer. The electrostatic image developer may be a magnetic or non-magnetic one-component electrostatic image developer containing at least the toner of the present invention, or a two-component electrostatic toner containing at least the toner of the present invention and a carrier. It may be an image developer.

When the one-component electrostatic image developer is a magnetic one-component electrostatic image developer, a magnetic powder is added, or all or a part of the black colorant in the colorant is replaced with a magnetic powder. be able to. As the magnetic powder, any conventionally known magnetic powder can be used. For example, metals such as iron, cobalt and nickel and alloys thereof, Fe ₃ O ₄ , γ-Fe ₂ O ₃ , Metal oxides such as cobalt-added iron oxide and magnetite, MnZn ferrite, Ni
Ferrites such as Zn ferrite and the like. These magnetic materials are generally used by adding 30 to 70% by weight.

In the two-component electrostatic image developer, the carrier is not particularly limited, and a carrier known per se, for example, a resin-coated carrier and the like can be preferably used.
The resin-coated carrier is obtained by coating the surface of a core material with a resin. Examples of the core material include magnetic powder such as iron powder, ferrite powder, and nickel powder.
Examples of the resin include a fluorine-based resin, a vinyl-based resin, and a silicone-based resin.

The electrostatic image developer containing the toner of the present invention can be suitably used in various image forming methods.
The image forming method of the present invention uses an electrostatic image developer containing the toner of the present invention as the electrostatic image developer. The image forming method of the present invention is a known image forming method, for example,
A charging step of uniformly charging the surface of the electrostatic latent image carrier; an exposing step of exposing the surface of the electrostatic latent image carrier to form an electrostatic latent image; Developing the electrostatic latent image using an electrostatic charge image developer to form a toner image, transferring the toner image onto a transfer material, and fixing the toner image on the transfer material Fixing process,
And the like. Further, the transfer step and the fixing step may be performed simultaneously.

The image forming apparatus of the present invention uses an electrostatic image developer containing the toner of the present invention as the electrostatic image developer. An image forming apparatus according to the present invention includes: a charging unit configured to uniformly charge a surface of an electrostatic latent image carrier; an exposing unit configured to expose the surface of the electrostatic latent image carrier to form an electrostatic latent image; Developing means for developing the electrostatic latent image formed on the surface of the carrier using an electrostatic charge image developer to form a toner image; transferring means for transferring the toner image onto a material to be transferred; Fixing means for fixing the toner image on the material. Each means will be described together with each step of the image forming method.

According to the image forming method of the present invention, if necessary, a static elimination step for removing the electrostatic latent image remaining on the surface of the electrostatic latent image carrier, and a residual image on the surface of the electrostatic latent image carrier in the transfer step A cleaning process for removing the removed toner or attached paper dust, dust and the like may be performed. However, the toner of the present invention can be applied to a so-called cleaningless system that does not include a cleaning step.

In the charging step, conventionally known methods such as non-contact charging with a corotron or the like and contact charging with a charging roll, a charging film, a charging brush or the like can be applied. In the exposure step, a conventionally known method can be applied, and an electrostatic latent image is formed on a latent image carrier such as a photosensitive layer or a dielectric layer by electrophotography or electrostatic recording. As the photosensitive layer of the latent image carrier used in the present invention, known materials such as organic and amorphous silicon can be used. When the latent image carrier is cylindrical, the latent image carrier is obtained by a known manufacturing method such as extruding aluminum or an aluminum alloy, followed by surface processing. It is also possible to use a belt-shaped latent image carrier.

For the exposure step, a conventionally known method can be applied.
It can be performed by an electrophotographic method or an electrostatic recording method.

In the developing step, the developer layer containing the toner formed on the developer carrier is transported to the developing nip, and the developer layer and the electrostatic latent image carrier are brought into contact with each other at the developing section or a certain gap is formed. The electrostatic latent image is developed with toner while applying a bias between the developer carrier and the electrostatic latent image carrier.
As the electrostatic image developer, a two-component electrostatic image developer that charges toner using a carrier or a one-component electrostatic charge that forms a thin layer of toner on a developer carrier using an elastic blade and charges the toner. An image developer is used.

In the transfer step, a transfer roller, a transfer belt or the like is brought into pressure contact with the electrostatic latent image carrier to transfer the toner image to the transfer object, or a non-contact type transfer to transfer the toner image to the transfer object using a corotron or the like. Things are used. In the full-color image forming method, a method in which yellow, magenta, cyan, and black toners are sequentially transferred using a transfer roll around which transfer paper is spread, and after multi-transfer of four-color toner to a belt-shaped or cylindrical intermediate transfer body A conventionally known method such as a method of transferring the image to a transfer target is used.

In the fixing step, the toner image transferred to the transfer medium is fixed by a fixing device. As the fixing means, a heat fixing method using a heat roll is preferably used.

In the charge elimination step, a light source is used separately from an exposure light source for image formation for the purpose of initializing (static elimination) the electrostatic latent image carrier after development or stabilizing image forming characteristics. Then, the electrostatic latent image remaining on the surface of the electrostatic latent image carrier is removed.

The cleaning step is a step of removing the toner remaining on the latent image carrier or the intermediate transfer body without being transferred in the transfer step by a cleaner, but the present invention is also applicable to a cleanerless apparatus. is there. In the case of having a cleaning step, known ones such as blade cleaning, brush cleaning and roller cleaning may be mentioned. Elastic rubber such as silicone rubber or urethane rubber is used for blade cleaning.

Examples of the medium to be transferred (recording material) include plain paper and OHP sheets used in electrophotographic copying machines and printers. If it is desired to further improve the smoothness of the image surface after fixing, a material having a surface as smooth as possible may be used, for example, coated paper in which the surface of plain paper is coated with a resin or the like, art paper for printing, etc. Is mentioned.

According to the image forming method of the present invention, an image can be formed by multi-transferring a multicolor toner onto a transfer medium.

FIG. 1 is a schematic diagram showing an example of an image forming apparatus suitably used in the image forming method of the present invention.
The image forming apparatus shown in FIG.
1, a roller type charger 12, an exposing device 13, a developing device 14 including developing devices 14 a, 14 b, 14 c, and 14 d equipped with cyan, magenta, yellow, and black developers, and a belt-shaped intermediate device The transfer body 15, the cleaner 16, and the light neutralizer 17 are arranged in this order. The intermediate transfer member 15 includes support rollers 18a, 18b,
18c. The support roller 18a is in pressure contact with the photoconductor 11 via the intermediate transfer body 15. The support roller 18c is pressed by a transfer roll 19 via the intermediate transfer member 15. The transfer roll 19
And a pair of heat roller fixing devices including a heating roller 21 and a pressure roller 22 for fixing the toner image transferred to the transfer-receiving body 20 by the heat roller 21.

Using the image forming apparatus shown in FIG. 1, an image is formed as follows. The photoconductor 11 charged by the charger 12 is exposed by the exposure device 13 based on the image information of cyan, magenta, and yellow to form a latent image on the photoconductor 11. The latent images on the photoconductor 11 are developed by developing units 14a, 14b, 14c, 1
At 4d, each is developed to form a toner image. The developed toner image is transferred onto a belt-like intermediate transfer body 15. The toner image on the intermediate transfer body 15 is
5 in the direction of arrow P, the transfer roller 1 pressed against the support roller 18c via the intermediate transfer member 15.
Move to between 9. When the toner image on the intermediate transfer member 15 passes between the support roller 18c and the transfer roller 19 pressed into contact with the intermediate transfer member 15 (nip portion), the toner image passed through the nip portion The image is transferred onto the transfer body 20. The toner image transferred onto the transfer body 20 is fixed on the transfer body 20 by passing the transfer body 20 between the heating roller 21 and the pressure roller 22 to form an image. After the toner image on the photoconductor 11 is transferred to the transfer-receiving body 20, the toner image remaining on the photoconductor 11 is removed by the cleaner 16, and the residual charge remaining on the photoconductor 11 is removed by the photo-eliminator 17. The charge is removed and the image is prepared for the next image formation.

[0066]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the following description, all “parts” mean “parts by weight” unless otherwise specified.

(Preparation of Titanium Oxide Fine Particles A) Ilmenite ore was dissolved in sulfuric acid to separate iron, and the resulting TiS
O ₄ was hydrolyzed to produce TiO (OH) ₂ . After washing the formed TiO (OH) ₂ with water and filtering, 700 ° C.
To obtain titanium oxide fine particles having an average primary particle diameter of 20 nm. Thereafter, the titanium oxide fine particles were dispersed in a toluene solvent, 20 parts of decyltrimethoxysilane was added to 100 parts of titanium oxide, and the mixture was added with a sand grinder.
The particles were agglomerated by wet pulverization for 1 minute, and then heated and dried by a pressure kneader to perform a hydrophobic treatment. Further, it was pulverized by a jet mill to obtain hydrophobic titanium oxide fine particles A. When the volume resistivity of the obtained titanium oxide fine particles A was measured, it was 2 × 10 ¹² Ωcm. The measurement of the volume resistivity was performed as described above. (Preparation of titanium oxide fine particles B) The treatment amount of decyltrimethoxysilane was 25
Except for the above, titanium oxide fine particles B were obtained in the same manner as in the preparation of titanium oxide fine particles A. When the volume resistivity of the obtained titanium oxide fine particles B was measured, it was 8 × 10 ¹² Ωc.
m.

(Preparation of titanium oxide fine particles C) Titanium oxide fine particles C were obtained in the same manner as in the preparation of titanium oxide fine particles A, except that the decyltrimethoxysilane treatment was changed to 15 parts of octadecyltrimethoxysilane. The volume resistivity of the obtained titanium oxide fine particles C was 3 × 10 ¹³ Ωcm.

(Preparation of Titanium Oxide Fine Particles D) The decyltrimethoxysilane treatment was carried out using hexyltrimethoxysilane 30.
Except for the above, titanium oxide fine particles D were obtained in the same manner as in the preparation of titanium oxide fine particles A. The volume resistivity of the obtained titanium oxide fine particles D was 3 × 10 ¹⁰ Ωcm.

(Preparation of Titanium Oxide Fine Particles E) Ilmenite ore was dissolved in sulfuric acid to separate iron, and the resulting Ti
The SO ₄ is hydrolyzed to produce a TiO (OH) _2. After washing the formed TiO (OH) ₂ with water and filtering, 7
The mixture was fired at 00 ° C. to obtain titanium oxide fine particles having an average primary particle diameter of 20 nm. Thereafter, the titanium oxide fine particles are dispersed in a toluene solvent, 20 parts of isobutyltrimethoxysilane is added to 100 parts of titanium oxide, and the fine particles are aggregated by wet grinding with a sand grinder for 5 minutes. It was heated and dried to perform a hydrophobic treatment. The powder was further pulverized with a pin mill to obtain hydrophobic titanium oxide fine particles E. The volume resistivity of the obtained titanium oxide fine particles E was 3 × 10 ⁹ Ωcm.

(Preparation of titanium oxide fine particles F) Titanium oxide fine particles F were obtained in the same manner as in the preparation of titanium oxide fine particles E, except that the treatment amount of isobutyltrimethoxysilane was changed to 30 parts. The volume resistivity of the obtained titanium oxide fine particles F was 8 × 10 ⁹ Ωcm.

(Preparation of titanium oxide fine particles G) Titanium oxide fine particles G were obtained in the same manner as in the preparation of titanium oxide fine particles A, except that the decylsilane treatment was changed to 30 parts of octadecyltrimethoxysilane. The volume resistivity of the obtained titanium oxide fine particles G was 2 × 10 ¹⁴ Ωcm.

(Preparation of Titanium Oxide Fine Particles H) A titanium oxide fine particle E was prepared in the same manner as in the preparation of titanium oxide fine particles E, except that the octadecyltrimethoxysilane treatment was changed to 20 parts.
Titanium oxide fine particles H were obtained. The volume resistivity of the obtained titanium oxide fine particles H was 6 × 10 ¹³ Ωcm.

[Production of Toner Base Particles] (Production of Cyan Toner Base Particles C) A mixture represented by the following composition (1) was premixed with a Henschel mixer, and then mixed.
The mixture was kneaded by a shaft extruder at a set temperature of 140 ° C., a screw rotation speed of 300 rpm, and a supply speed of 150 kg / h. After cooling, the mixture was roughly pulverized, finely pulverized with a jet mill, and further classified with an air classifier to obtain cyan toner mother particles C having a volume average particle diameter D50 of 6.5 μm. The sphericity of the cyan toner mother particles C is 15
It was 0.

-Composition (1)--95 parts of polyester resin (weight of terephthalic acid / bisphenol A ethylene oxide adduct, average molecular weight Mw: 12000, Tg: 65 ° C, softening point: 100 ° C)-Copper phthalocyanine blue pigment I. Pigment Blue 15: 3 5 parts

(Production of Magenta Toner Base Particles M) I. Pigment Red 57: 1, and magenta toner base particles M having a D50 of 6.5 μm were obtained in the same manner as the cyan toner base particles C, except that 5 parts of Pigment Red 57: 1 were used. The degree of spheroidization of the magenta toner base particles M was 155.

(Production of Yellow Toner Base Particles Y) I. Pigment Yellow 180, except that 10 parts of CI Pigment Yellow 180 were used, to obtain yellow toner base particles Y having a D50 of 6.5 μm in the same manner as the cyan toner base particles C. The sphericity of the yellow toner mother particles Y was 153.

(Production of Black Toner Base Particles K) Black toner base particles K having a D50 of 6.5 μm were obtained in the same manner as the cyan toner base particles C, except that 4 parts of carbon black was used as the pigment. The degree of sphericity of the black toner base particles K was 145.

(Manufacture of Carrier) The carrier core “F3
5 "(Cu-Zn ferrite: manufactured by Powder Tech) 1
00 parts were coated with 3 parts of PMMA using a pressure kneader and sieved to obtain a 35 μm carrier.

[Image Forming Apparatus 1] As the image forming apparatus 1, the image forming apparatus shown in FIG. 1 was used. Specific experimental conditions are as follows. Photoconductor: OPC (φ84) ROS: LED (400 dpi) Process speed: 160 mm / s Latent image potential: background portion = −550 V, image portion = −150 V Developing roll (common to first to fourth developing devices): magnet fixed, Sleeve rotation, magnet magnetic flux density = 500G (on the sleeve), sleeve diameter = φ25, sleeve rotation speed =
300 mm / s Distance between photoconductor and developing roll (common to first to fourth developing units):
0.5 mm Distance between developer layer thickness regulating member and developing roll (common to first to fourth developing devices): 0.5 mm Developing bias (common to first to fourth developing devices): DC component = −500 V, AC Component = 1.5 kVP-P (8 kHz
z) Transfer conditions: corotron transfer (wire diameter = 85 μm) Fixing conditions: Fluororoll, no oil supply Evaluation environment: 23 ° C., 50% RH (however, Examples 1 to 5,
Comparative Examples 1 to 4 are performed under high temperature and high humidity or low temperature and low humidity as described later. )

(Example 1) Cyan toner mother particles C100
Part is titanium oxide fine particle A 1.0 part and average primary particle diameter 40
1.2 parts of silica treated with silicone oil having a thickness of 1.5 nm were mixed using a Henschel mixer, and further mixed with a wind sieve.
The mixture was sieved at μm to obtain cyan toner 1. Calculated surface coverage C _{0 of} this cyan toner 1 with titanium oxide fine particles.
Is 26.9%. As in the case of cyan toner 1, 100 parts of toner base particles and 1.0 part of titanium oxide fine particles A and silicone oil-treated silica having an average primary particle diameter of 40 nm were used.
Two parts were mixed using a Henschel mixer, and sieved at 45 μm using a wind sieving machine to obtain magenta toner 1, yellow toner 1, and black toner 1. The calculated surface coverage C ₀ of these toners by titanium oxide fine particles is:
It is 26.9% similarly to the cyan toner. Measured coverage C of titanium oxide fine particles and adhesion C of titanium oxide fine particles obtained by XPS measurement of each of cyan toner 1, magenta toner 1, yellow toner 1, and black toner 1.
Table 1 shows / C ₀ . The average primary particle diameter (a1) and the average aggregate particle diameter (a) of the titanium oxide fine particles in the obtained toner
2) Observation with SEM at accelerating voltage 5kv, 30,000 times
It was measured. Table 1 shows the ratio a2 / a1 between the average primary particle size (a1) and the average aggregated particle size (a2).

Cyan toner 1 (10 parts) and 100 parts of the carrier were mixed in a V blender to obtain cyan developer 1. Further, magenta developer 1, yellow developer 1, and black developer 1 were obtained in the same manner as cyan developer 1. Using each of the obtained developers 1, in the image forming apparatus 1,
10 ° C, 10% RH, low temperature and low humidity environment and 28 ° C, 90%
Print test of 200,000 sheets under high temperature and high humidity environment of% RH, respectively, and the following charge amount, density, fog,
Examination of filming streaks, color reproducibility, and transferability showed that there was little difference in environment between toner charging and image density, no fog or white streaks occurred, good toner transferability, and a small amount of transfer residual recovered toner. The result was obtained. Table 2 shows the results.

<Measurement of charge amount>: Measured by Toshiba blow-off tribo measurement method. <Density>: The solid portion density of the primary color (yellow, magenta, cyan) is measured by a density measuring device manufactured by X-rite, Xr.
The measurement was performed using item 404A, and the evaluation was performed in the following three grades of ○, Δ, and × in descending order. ○ ≧ 1.3 1.3> △ ≧ 1.1, × <1.1

<Fog>: The background portion of the full-color image on the paper was observed with a 50 × loupe, and the occurrence of fog was checked.
As shown below, the sensitivity was evaluated in three stages of ○, Δ, and ×. ：: no fog at all △: slightly fog ×: considerably fog

<Filming streaks>: The number of streaks generated in an image obtained by fully developing the toner on A4 paper was observed.
The evaluation was made in three stages of △, Δ, and × in order of the number of muscles generated. ：: 5 or less △: 6 to 10 ×: 11 or more

<Color Reproducibility>: Variations in the solid part density of the secondary colors (red, green, blue) were evaluated in three different scales of ○, Δ, and × as shown below. ○: Uniform △: Some color unevenness ×: Large color unevenness

<Transferability> Transfer rate (%) of primary color (yellow, magenta, cyan) (toner weight per unit area on paper / (toner weight per unit area on electrostatic latent image carrier) ) × 100) was evaluated in three stages of ○, Δ, and × in descending order as shown below. ○ ≧ 85% 85%> △ ≧ 75% × <75%

(Example 2) In Example 1, except that the titanium oxide fine particles A were changed to the titanium oxide fine particles B,
Cyan toner 2, magenta toner 2, yellow toner 2, black toner 2, cyan developer 2, magenta developer 2, yellow developer 2, and black developer 2 were obtained in exactly the same manner as in Example 1. The calculated surface coverage C ₀ of the cyan toner 2, the magenta toner 2, the yellow toner 2, and the black toner 2 by the titanium oxide fine particles is 26.9%, and the actually measured coating of the titanium oxide fine particles obtained by each XPS measurement. Rate C, and adhesion rate C of titanium oxide fine particles
/ C ₀ is shown in Table 1. The average primary particle diameter (a1) and the average aggregated particle diameter (a1) of the titanium oxide fine particles in the obtained toner were observed and measured by SEM at an acceleration voltage of 5 kv and 30,000 times. Table 1 shows the ratio a2 / a1 between the average primary particle size (a1) and the average aggregated particle size (a2). Using each of the obtained developers 2, a print test was performed in the image forming apparatus 1 in the same manner as in Example 1, and the charge amount, density, fog, filming streak, and color reproducibility were examined.
Good results were obtained with little environmental differences in toner charging and image density, no fog or white streaks, good toner transferability, and a small amount of transfer residual recovered toner. Table 2 shows the results.

(Example 3) In Example 1, except that the titanium oxide fine particles A were replaced with the titanium oxide fine particles C,
In the same manner as in Example 1, cyan toner 3, magenta toner 3, yellow toner 3, black toner 3, cyan developer 3, magenta developer 3, yellow developer 3, and black developer 3 were obtained. The calculated surface coverage C ₀ of the cyan toner 3, the magenta toner 3, the yellow toner 3, and the black toner 3 by the titanium oxide fine particles is 26.9%.
Table 1 shows the measured coverage C of the titanium oxide fine particles and the adhesion ratio C / C ₀ of the titanium oxide fine particles obtained by the respective XPS measurements. The average primary particle diameter (a1) and the average aggregated particle diameter (a1) of the titanium oxide fine particles in the obtained toner were observed and measured by SEM at an acceleration voltage of 5 kv and 30,000 times. Table 1 shows the ratio a2 / a1 between the average primary particle size (a1) and the average aggregated particle size (a2). Using each of the obtained developers 3, 10
, 10% RH, low temperature and low humidity environment and 28 ° C, Example 1
A print test was performed in the image forming apparatus 1 in the same manner as described above, and the charge amount, density, fog, filming streak, and color reproducibility were examined. And good results were obtained with good toner transferability and a small amount of toner remaining after transfer. Table 2 shows the results.

(Example 4) In Example 1, except that the titanium oxide fine particles A were replaced with the titanium oxide fine particles D,
Cyan toner 4, magenta toner 4, yellow toner 4, black toner 4, cyan developer 4, magenta developer 4, yellow developer 4, and black developer 4 were obtained in exactly the same manner as in Example 1. The calculated surface coverage C ₀ of the cyan toner 4, the magenta toner 4, the yellow toner 4, and the black toner 4 by the titanium oxide fine particles is 26.9%.
Table 1 shows the measured coverage C of the titanium oxide fine particles and the adhesion ratio C / C ₀ of the titanium oxide fine particles obtained by the respective XPS measurements. The average primary particle diameter (a1) and the average aggregated particle diameter (a1) of the titanium oxide fine particles in the obtained toner were observed and measured by SEM at an acceleration voltage of 5 kv and 30,000 times. Table 1 shows the ratio a2 / a1 between the average primary particle size (a1) and the average aggregated particle size (a2). A print test was performed using each of the obtained developers 4 in the image forming apparatus 1 in the same manner as in Example 1, and the charge amount, density, fog, filming streak, and color reproducibility were examined.
Good results were obtained with little environmental differences in toner charging and image density, no fog or white streaks, good toner transferability, and a small amount of transfer residual recovered toner. Table 2 shows the results.

(Example 5)
The addition amount of the fine particles A was 1.5 parts, and the average primary particle diameter was 40.
1.5 parts by mass of silicone oil treated silica
Except that cyan was used in the same manner as in Example 1.
Toner 5, magenta toner 5, yellow toner 5, black
Toner 5, cyan developer 5, magenta developer 5,
Yellow developer 5 and black developer 5 were obtained. Sianto
Toner 5, magenta toner 5, yellow toner 5, black toner
Calculated surface coating of Kutner 5 with titanium oxide fine particles
Rate C ₀Is 40.0%, according to each XPS measurement.
Measured coverage C of titanium oxide fine particles obtained and oxidation
Adhesion rate of titanium fine particles C / C₀Is shown in Table 1. Also,
Average primary particle diameter of titanium oxide fine particles in the obtained toner
(A1) and average agglomerated particle diameter (a1) are accelerating voltage by SEM
Observation and measurement were performed at 5 kv and 30,000 times. Average primary particle
Ratio a2 / a1 between diameter (a1) and average aggregated particle diameter (a2)
Are shown in Table 1. Example 1 was prepared using each developer 5 obtained.
A print test is performed in the image forming apparatus 1 in the same manner as described above.
, Charge amount, density, fog, filming streak, color reproducibility
Was examined, the differences in toner charging and image density
Less fog and white streaks, and toner transfer
Good results with good transferability and low residual transfer toner recovery
Was. Table 2 shows the results.

Comparative Example 1 In Example 1, except that the titanium oxide fine particles A were replaced with the titanium oxide fine particles E,
Cyan toner 6, magenta toner 6, yellow toner 6, black toner 6, cyan developer 6, magenta developer 6, yellow developer 6, and black developer 6 were obtained in exactly the same manner as in Example 1. The calculated surface coverage C ₀ of the cyan toner 6, the magenta toner 6, the yellow toner 6, and the black toner 6 by the titanium oxide fine particles is 26.9%.
Table 1 shows the measured coverage C of the titanium oxide fine particles and the adhesion ratio C / C ₀ of the titanium oxide fine particles obtained by the respective XPS measurements. The average primary particle diameter (a1) and the average aggregated particle diameter (a1) of the titanium oxide fine particles in the obtained toner were observed and measured by SEM at an acceleration voltage of 5 kv and 30,000 times. Table 1 shows the ratio a2 / a1 between the average primary particle size (a1) and the average aggregated particle size (a2). Using each of the obtained developers 6, a print test was performed in the image forming apparatus 1 in the same manner as in Example 1, and the charge amount, density, fog, filming streak, and color reproducibility were examined.
Although there is little environmental difference in toner charging and image density, fogging and white streaks are good, but due to poor secondary transferability and retransfer of toner, the color reproducibility of full-color images is uneven, and transfer residue As a result, a large amount of collected toner was obtained. Table 2 shows the results.

Comparative Example 2 In Example 1, except that the titanium oxide fine particles A were replaced by the titanium oxide fine particles F,
Cyan toner 7, magenta toner 7, yellow toner 7, black toner 7, cyan developer 7, magenta developer 7, yellow developer 7, and black developer 7 were obtained in exactly the same manner as in Example 1. The calculated surface coverage C ₀ of the cyan toner 7, the magenta toner 7, the yellow toner 7, and the black toner 7 by the titanium oxide fine particles is 26.9%.
Table 1 shows the measured coverage C of the titanium oxide fine particles and the adhesion ratio C / C ₀ of the titanium oxide fine particles obtained by the respective XPS measurements. The average primary particle diameter (a1) and the average aggregated particle diameter (a1) of the titanium oxide fine particles in the obtained toner were observed and measured by SEM at an acceleration voltage of 5 kv and 30,000 times. Table 1 shows the ratio a2 / a1 between the average primary particle size (a1) and the average aggregated particle size (a2). Using each of the obtained developers 7, a print test was performed in the image forming apparatus 1 in the same manner as in Example 1, and the charge amount, density, fog, filming streak, and color reproducibility were examined.
Although there is little environmental difference in toner charging and image density, fogging and white streaks are good, but due to poor secondary transferability and retransfer of toner, the color reproducibility of full-color images is uneven, and transfer residue As a result, a large amount of collected toner was obtained. Table 2 shows the results.

(Comparative Example 3) In Example 1, except that the titanium oxide fine particles A were replaced with the titanium oxide fine particles G,
Cyan toner 8, magenta toner 8, yellow toner 8, black toner 8, cyan developer 8, magenta developer 8, yellow developer 8, and black developer 8 were obtained in exactly the same manner as in Example 1. The calculated surface coverage C ₀ of the cyan toner 8, the magenta toner 8, the yellow toner 8, and the black toner 8 by the titanium oxide fine particles is 26.9%.
Table 1 shows the measured coverage C of the titanium oxide fine particles and the adhesion ratio C / C ₀ of the titanium oxide fine particles obtained by the respective XPS measurements. The average primary particle diameter (a1) and the average aggregated particle diameter (a1) of the titanium oxide fine particles in the obtained toner were observed and measured by SEM at an acceleration voltage of 5 kv and 30,000 times. Table 1 shows the ratio a2 / a1 between the average primary particle size (a1) and the average aggregated particle size (a2). Using each of the obtained developers 8, a print test was performed in the image forming apparatus 1 in the same manner as in Example 1, and the charge amount, density, fog, filming streak, and color reproducibility were examined.
Although the toner transferability was good, the difference in toner charging environment was large, and the image density was reduced in a low-temperature and low-humidity environment, and fogging was observed in a high-temperature and high-humidity environment. Table 2 shows the results.

Comparative Example 4 In Example 1, except that the titanium oxide fine particles A were changed to the titanium oxide fine particles H,
Cyan toner 9, magenta toner 9, yellow toner 9, black toner 9, cyan developer 9, magenta developer 9, yellow developer 9, and black developer 9 were obtained in exactly the same manner as in Example 1. The calculated surface coverage C ₀ of the cyan toner 9, the magenta toner 9, the yellow toner 9, and the black toner 9 by the titanium oxide fine particles is 26.9%, and the actually measured coating of the titanium oxide fine particles obtained by each XPS measurement. Rate C, and adhesion rate C of titanium oxide fine particles
/ C ₀ is shown in Table 1. The average primary particle diameter (a1) and the average aggregated particle diameter (a1) of the titanium oxide fine particles in the obtained toner were observed and measured by SEM at an acceleration voltage of 5 kv and 30,000 times. Table 1 shows the ratio a2 / a1 between the average primary particle size (a1) and the average aggregated particle size (a2). Using each of the obtained developers 9, a print test was performed in the image forming apparatus 1 in the same manner as in Example 1, and the charge amount, density, fog, filming streak, and color reproducibility were examined.
There is a large difference in the environment of toner charging.
Filming of titanium oxide on the electrostatic latent image carrier also occurred. Table 2 shows the results.

[0096]

[Table 1]

[0097]

[Table 2]

As shown in Tables 1 and 2, the toner for developing an electrostatic image of the present invention is excellent in toner charging stability and transferability, and has little release and aggregation of additives. It can be seen that not only a highly reliable image having excellent density and color reproducibility can be obtained, but also excellent in ecological characteristics with a small amount of transfer residual recovery toner.

(Embodiment 6) C.I. I. Pigment Blue B
15: 3 (20 parts by weight), 75 parts by weight of ethyl acetate, 4 parts by weight of disparone DA-703-50 (polyester amide amine salt, manufactured by Kusumoto Kasei Co., Ltd.) from which the solvent was removed, Solsperse 5000 (pigment derivative, Zeneca) (stock)
1 part by weight was dissolved / dispersed using a sand mill to prepare a pigment dispersion. Further, 30 parts by weight of paraffin wax (melting point: 89 ° C.) and 270 parts by weight of ethyl acetate were cooled to 10 ° C. by a DCP mill as a release agent and wet-pulverized to prepare a wax dispersion. Bisphenol A
Polyester resin composed of propylene oxide adduct, bisphenol A ethylene oxide adduct, and terephthalic acid derivative (Mw = 6000, Tg60 ° C., Tm10
136 parts by weight of 6 ° C., an acid value of 4 mg KOH / g), 34 parts by weight of a pigment dispersion and 56 parts by weight of ethyl acetate were stirred, and 75 parts by weight of a wax dispersion were added thereto. A liquid). On the other hand, calcium carbonate 4
0 parts by weight, 124 parts by weight of a calcium carbonate dispersion dispersed in 60 parts by weight of water, 99 parts by weight of a 2% aqueous solution of cellogen BS-H (Daiichi Kogyo Seiyaku Co., Ltd.) and 157 parts by weight of water were mixed with a homogenizer (Ultra Turrax). : IKA Co., Ltd.) for 5 minutes (this solution was designated as solution B). Further, 345 parts by weight of the solution B and 250 parts by weight of the solution A were stirred using a homogenizer (Ultra Turrax: manufactured by IKA) to suspend the mixture. The mixture was stirred with a propeller stirrer at room temperature and normal pressure for 48 hours to remove the solvent. Then add hydrochloric acid,
After removing the calcium carbonate, the particles were washed with water, dried and classified to obtain toner base particles α. The average particle diameter of the toner mother particles α was 6.5 μm, and the degree of sphericity was 110.

Next, an acid was added to 100 parts by weight of the toner base particles α.
1.0 parts by weight of titanium oxide fine particles A and an average primary particle diameter of 100
nm silicon oxide fine particles (“KMP-105” (Shin-Etsu Chemical)
Was treated with hexamethyldisilazane.
) 1.2 parts by weight were mixed with a sample mill and toner 10
Was prepared. Calculation of Titanium Oxide Fine Particles of Toner 10
Surface coverage C₀Is 26.9% and the toner 10
Actual measurement of titanium oxide fine particles obtained by XPS measurement
Coverage C and adhesion ratio C / C of titanium oxide fine particles ₀Is Table 3
Shown in In addition, the titanium oxide fine particles in the obtained toner
The average primary particle size (a1) and the average aggregated particle size (a2) are S
Observe and measure with EM at acceleration voltage 5kv, 30,000 times
Was. Average primary particle size (a1) and average aggregated particle size (a2)
Table 3 shows the ratio a2 / a1 with respect to. With the obtained toner 10
Ferrite key coated on the surface with poly (methyl methacrylate)
And humidity in an environment of 20 ° C and 50% humidity.
Thus, a developer 10 was obtained. Using the obtained developer 10,
In the image forming apparatus 1 with the cleaner removed, 100,
Perform a print test of 000 sheets and check the following transferability, density,
When I checked fog, I found 100,000 copies
A clear image with sufficient density was obtained even afterwards. That
Table 3 shows the results.

<Transferability>: Initial transfer rate and 10,000
The transfer rate after performing zero copy was measured. Toner transfer rate (%) (weight of toner transferred to paper / (weight of toner transferred to paper + weight of untransferred toner on photosensitive drum))
× 100) in the descending order of ◎, ○, △,
The evaluation was made in four stages of x. ◎ ≧ 99% 99%> ○ ≧ 98% 98%> △ ≧ 95% × <95%

<Density>: X-write
The concentration was measured by X-rite 404A manufactured by the company, and evaluated in the following three grades of ○, Δ, and × in descending order as follows. ○ ≧ 1.3 1.3> △ ≧ 1.1, × <1.1

<Fog>: The background portion of the full-color image on the paper was observed with a 50 × loupe, and the occurrence of fog was checked.
As shown below, the sensitivity was evaluated in three stages of ○, Δ, and ×. ：: no fog at all △: slightly fog ×: considerably fog

Example 7 A toner 11 and a developer 11 were obtained in the same manner as in Example 6, except that the titanium oxide fine particles A were replaced with the titanium oxide fine particles C. The calculated surface coverage C ₀ of the toner 11 by the titanium oxide fine particles is 26.9%.
Table 3 shows the measured coverage C of the titanium oxide fine particles obtained by the XPS measurement of the toner 11 and the adhesion ratio C / C ₀ of the titanium oxide fine particles. The average primary particle diameter (a1) and average agglomerated particle diameter (a2) of the titanium oxide fine particles in the obtained toner were determined by SEM at an accelerating voltage of 5 kv and 300 kV.
The observation and measurement were performed at a magnification of 00. Table 3 shows the ratio a2 / a1 between the average primary particle size (a1) and the average aggregated particle size (a2).
Using the obtained developer 11, a print test was performed in the image forming apparatus 1 from which the cleaner was removed in the same manner as in Example 6, and transferability, density, and fog were examined. Also, a clear image with sufficient density was obtained. Table 3 shows the results.

Example 8 A toner 12 and a developer 12 were obtained in the same manner as in Example 6, except that the titanium oxide fine particles A were replaced with the titanium oxide fine particles D. The calculated surface coverage C ₀ of the toner 12 by the titanium oxide fine particles is 26.9%.
Table 3 shows the measured coverage C of the titanium oxide fine particles and the adhesion ratio C / C ₀ of the titanium oxide fine particles obtained by the XPS measurement of the toner 12. The average primary particle diameter (a1) and average agglomerated particle diameter (a2) of the titanium oxide fine particles in the obtained toner were determined by SEM at an accelerating voltage of 5 kv and 300 kV.
The observation and measurement were performed at a magnification of 00. Table 3 shows the ratio a2 / a1 between the average primary particle size (a1) and the average aggregated particle size (a2).
Using the obtained developer 12, a print test was carried out in the image forming apparatus 1 from which the cleaner was removed in the same manner as in Example 6, and transferability, density, and fog were examined. Also, a clear image with sufficient density was obtained. Table 3 shows the results.

Example 9 The addition amount of titanium oxide fine particles A was 1.5 parts by weight, and the average primary particle diameter was 100 nm.
Silicon oxide fine particles having an average primary particle diameter of 40 nm instead of 1.2 parts by weight of silicon oxide fine particles ("KMP-105" (manufactured by Shin-Etsu Chemical Co., Ltd.) treated with hexamethyldisilazane). A toner 13 and a developer 13 were obtained in the same manner as in Example 6, except that 0.5 part by weight was added. The calculated surface coverage C ₀ of the toner 13 by the titanium oxide fine particles was 40.0%, and the XPS
Table 3 shows the measured coverage C of the titanium oxide fine particles and the adhesion C / C ₀ of the titanium oxide fine particles obtained by the measurement. The average primary particle size (a1) and average aggregated particle size (a2) of the titanium oxide fine particles in the obtained toner were SEM.
Was observed and measured at an acceleration voltage of 5 kv and a magnification of 30,000. Table 3 shows the ratio a2 / a1 between the average primary particle size (a1) and the average aggregated particle size (a2). A print test was performed using the obtained developer 13 in the image forming apparatus 1 from which the cleaner was removed in the same manner as in Example 6, and the transferability, density, and fog were examined. Also, a clear image with sufficient density was obtained. Table 3 shows the results.

Comparative Example 5 A toner 14 and a developer 14 were obtained in the same manner as in Example 6, except that the titanium oxide fine particles A were replaced with the titanium oxide fine particles G. The calculated surface coverage C ₀ of the toner 14 by the titanium oxide fine particles is 26.9%.
Table 3 shows the measured coverage C of the titanium oxide fine particles obtained by the XPS measurement of the toner 14 and the adhesion ratio C / C ₀ of the titanium oxide fine particles. The average primary particle diameter (a1) and average aggregated particle diameter (a2) of the titanium oxide fine particles in the obtained toner were determined by SEM at an accelerating voltage of 5 kv and 3000.
Observation and measurement were performed at 0 magnification. Table 3 shows the ratio a2 / a1 between the average primary particle size (a1) and the average aggregated particle size (a2). A print test was performed using the obtained developer 14 in the image forming apparatus 1 from which the cleaner was removed in the same manner as in Example 6, and the transferability, density, and fog were examined.
After 100,000 copies, some fog was observed. Table 3 shows the results.

Comparative Example 6 A toner 15 and a developer 15 were obtained in the same manner as in Example 6, except that the titanium oxide fine particles A were replaced with the titanium oxide fine particles H. The calculated surface coverage C ₀ of the toner 15 by the titanium oxide fine particles is 26.9%.
Table 3 shows the measured coverage C of the titanium oxide fine particles obtained by the XPS measurement of the toner 15 and the adhesion ratio C / C ₀ of the titanium oxide fine particles. The average primary particle diameter (a1) and average aggregated particle diameter (a2) of the titanium oxide fine particles in the obtained toner were determined by SEM at an accelerating voltage of 5 kv and 3000.
Observation and measurement were performed at 0 magnification. Table 3 shows the ratio a2 / a1 between the average primary particle size (a1) and the average aggregated particle size (a2). A print test was performed using the obtained developer 15 in the image forming apparatus 1 in the same manner as in Example 6 to check transferability, density, and fog.
Fog was observed after copying 00 sheets. Table 3 shows the results.

(Example 10) With respect to 100 parts of toner α, 1.0 part by weight of titanium oxide fine particles A and silicon oxide fine particles having an average primary particle diameter of 100 nm (“KMP-105”)
1.2 parts by weight of a classified product (manufactured by Shin-Etsu Chemical Co., Ltd.) treated with hexamethyldisilazane were mixed in a sample mill to prepare a toner 16, which was combined with a developer 16 (a non-magnetic one-component developer). did. The calculated surface coverage C ₀ of the toner 16 with the titanium oxide fine particles was 26.9%.
Table 3 shows the measured coverage C of the titanium oxide fine particles and the adhesion ratio C / C ₀ of the titanium oxide fine particles obtained by the XPS measurement. The average primary particle diameter (a1) and average aggregated particle diameter (a2) of the titanium oxide fine particles in the obtained toner were observed and measured by SEM at an acceleration voltage of 5 kv and 30,000 times. Average primary particle size (a1) and average aggregated particle size (a2)
Table 3 shows the ratio a2 / a1 with respect to. A print test was performed using the obtained developer 16 in the same manner as in Example 6, and the transferability, density, and fog were checked.
Even after copying 0 sheets, a clear image with sufficient density was obtained. Table 3 shows the results. However, the image forming apparatus
The image forming apparatus 2 described below was used.

-Image Forming Apparatus Used for Evaluating Image Quality of Non-Magnetic One-Component Developer- The latent image carrier is charged by a roller charger, and then exposed to laser light to form an electrostatic latent image, which is then developed by aluminum. The developer is developed with a thin layer formed by a urethane rubber layer forming blade on the agent carrier. Here, in order to stabilize the conveyance of the toner, a developer supply roller rotating in the opposite direction to the developer carrying member was arranged in contact with the developer carrying member. The toner developed on the latent image carrier is transferred to transfer paper by a contact-type transfer roller and thermally fixed. The blade-type cleaner was used for cleaning the residual toner on the latent image carrier.
Here, the peripheral speed of the photoconductor is 100 mm / s, the peripheral speed of the developer carrier is 170 mm / s, and an AC voltage and a DC voltage are applied to the developer carrier and the developer supply roller to apply an electrostatic latent image. Was developed.

[0111]

[Table 3]

From Table 3, it can be seen that the toner for electrostatic charge development of the present invention has excellent transferability over a long period of time and has little fogging because of little aggregation of additives. Further, it can be seen that, by forming the toner into a spherical shape, the transferability is increased so that the toner is sufficiently applied to a cleanerless system, and the fluidity is improved, so that good image quality can be obtained.

[0113]

As described above, according to the present invention, the toner for developing an electrostatic image capable of obtaining a stable image quality for a long time with a small environment dependency of charging, the change in charging in toner transfer is small, and the present invention can be applied to multiple transfer and multiple transfer. It is possible to provide a toner for developing an electrostatic image and a toner for developing an electrostatic image capable of obtaining a stable and high transfer efficiency with less contamination of a charging member such as a carrier and no filming on an electrostatic latent image carrier.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an example of an image forming apparatus used for an image forming method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Photoreceptor 12 Roller type charger 13 Exposure device 14a, 14b, 14c, 14d Developing device 14 Developing device 15 Belt-shaped intermediate transfer body 16 Cleaner 17 Light eliminator 18a, 18b, 18c Support roller 19 Transfer roll 20 Cover Transfer body 21 heating roller 22 pressure roller

Continued on the front page (72) Inventor Hiroshi Sugizaki 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Yusaku Shibuya 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Matsuoka Hirotaka 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. (72) Inventor Akira Matsumoto 1600 Takematsu, Minamiashigara-shi, Kanagawa Fuji Xerox Co., Ltd. (72) Masahiro Okita 1600 Takematsu, Minamiashigara-shi, Kanagawa Fuji Fuji Xerox Co., Ltd. (72) Inventor Tsutomu Kubo 1600 Takematsu, Minamiashigara, Kanagawa Prefecture Fuji Xerox Co., Ltd. F term (reference) 2H005 AA08 AA21 AB10 CA21 CB07 EA01 EA07

Claims (3)

[Claims] 1. An electrostatic image developing toner containing toner base particles containing at least a binder resin and a colorant and titanium oxide fine particles, wherein the titanium oxide fine particles have a volume resistivity of 1 × 10 ¹⁰ to When the calculated coverage of the titanium oxide fine particles on the surface of the toner base particles is C ₀ and the actually measured coverage is C, the surface area of the toner base particles by the titanium oxide fine particles is 1 × 10 ¹⁴ Ωcm. Adhesion rate (C / C ₀ )
Is 0.3 or more. A charging step of uniformly charging the surface of the electrostatic latent image carrier; an exposing step of exposing the surface of the electrostatic latent image carrier to form an electrostatic latent image; Developing the electrostatic latent image formed on the toner image using an electrostatic image developer, forming a toner image, a transfer process of transferring the toner image onto a transfer material, and An image forming method, comprising: a fixing step of fixing a toner image, wherein the electrostatic image developer contains the toner for developing an electrostatic image according to claim 1. 3. A charging unit for uniformly charging the surface of the electrostatic latent image carrier, an exposing unit for exposing the surface of the electrostatic latent image carrier to form an electrostatic latent image, and a surface of the electrostatic latent image carrier. Developing means for forming a toner image by developing the electrostatic latent image formed on the toner image by using an electrostatic image developer; transferring means for transferring the toner image onto a material to be transferred; An image forming apparatus comprising: a fixing unit for fixing a toner image; wherein the electrostatic image developer contains the toner for developing an electrostatic image according to claim 1.