JP2001265051A - Electrostatic charge image developing tuner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonmagnetic single component developing toner having excellent durability which does not cause melt sticking of the toner powder on an electrifying member or filming on a photoreceptor or a developer carrying body, which causes little decrease in the image density for long-term continuous printing and which gives a good image without fog or stripes. SOLUTION: The nonmagnetic single component developing toner is prepared by incorporating first inorganic fine particles such as silica having <=20 nm average primary volume particle size and second inorganic fine particles such as silica having 30 nm to 1 μm average primary volume particle size as external additives into toner particles having at least a binder resin, coloring agent and electrification controlling agent. Further, particles containing cerium oxide as an essential component and at least one of other rare earth element compounds are incorporated into the toner particles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-magnetic one-component toner used for electrophotographic development.

[0002]

2. Description of the Related Art Powder toners used in electrophotography are:
Electrical properties such as triboelectric charging and electrical resistance related to development and transfer performance, thermal properties related to fixing performance and heat resistance (storage stability), and mechanical properties as a powder such as fluidity and hardness Therefore, an appropriate level according to the use condition is required.

As for electrophotography, US Pat. No. 2,29
Various methods are described in Japanese Patent Publication No. 7,691, Japanese Patent Publication No. 42-23910 and Japanese Patent Publication No. 43-24748, but in general, a photoconductive substance is used and photosensitive is performed by various means. An electrostatic latent image is formed on the body, and then the latent image is developed with a developer (toner for electrostatic charge development) to form a visible image. If necessary, the visible image is transferred to paper or the like, and then added. The image is fixed by pressure, heat, or solvent vapor to obtain a fixed image.

[0004] Many methods are known as a developing method in electrophotography. When roughly classified, fine particles (20 to 500 µm) of iron powder, ferrite, nickel, glass and the like can be roughly classified.
m), a two-component development method using a mixture of a carrier and a toner as a developer, and a one-component development method using a developer consisting of only a toner. In either method, generally, charge is injected into the toner in a triboelectric manner.

Representative examples of the two-component developing method include a cascade method described in US Pat. No. 2,618,552 and a magnetic brush method described in US Pat. No. 2,874,063. According to these methods, a good image can be obtained stably, but on the other hand, the image quality is deteriorated due to a change in the triboelectrification due to the contamination of the carrier surface by the toner or the like and a change in the mixing ratio of the carrier and the toner. This is likely to occur, and various measures must be taken in terms of equipment and materials in order to prevent this. However, as a result of providing such an additional function to the device, the developing device cannot be downsized.

The one-component developing method avoids such problems of the two-component developing method. For example, US Pat. No. 4,336,318 discloses a method using an electrically insulating magnetic toner. A method for developing is described. In these methods, the charge is injected into the toner by frictional charging between the toner particles and the toner carrier and the toner thinning member, or by the frictional charging between the toner particles, so that the electrostatic latent image on the photosensitive member is Electrostatically adheres to

This developing method does not use a carrier and does not require a device for controlling the mixing ratio between the carrier and the toner. Therefore, the problems of the two-component developing method can be avoided and the developing device can be reduced in size. Has the advantage of becoming

On the other hand, in the one-component developing method using a magnetic toner, the toner itself must have appropriate magnetic characteristics in order to form a magnetic brush layer of the toner on a metal sleeve. Magnetic materials such as magnetite and ferrite are essential materials in the toner components. The necessary content of these magnetic materials is slightly different depending on the developing conditions and the kind of the materials, but it can be generally said that the required content is 30 to 60% by weight.

However, the inclusion of such a magnetic material, which generally has a low electric resistance and easily absorbs moisture, causes a decrease in the electric resistance and moisture resistance of the toner itself, and as a result, a stable developing performance against environmental changes. It is difficult to obtain, and the image density or the background contamination level greatly varies in various use environments.

The fact that the proportion of the resin material as a binder contained in the toner is smaller than that of the two-component type toner is disadvantageous in terms of fixing performance in terms of design. And recently,
In consideration of the increasing use of color images, since many magnetic materials are colored, there arises a problem that colors that can be supported are limited or clear color image quality is difficult to obtain.

In order to solve the problems of the one-component developing method using such a magnetic toner, a non-magnetic one-component developing method which does not require magnetic properties of the toner has been proposed. Various apparatuses have been studied as such a method, but most of them are methods in which toner is attached to a developing sleeve or the like as a developer carrier by electrostatic force, and the toner is transported to a latent image surface and developed. The conventional magnetic one-component developing method is greatly different from the conventional magnetic one-component developing method in that a magnetic material is not an essential component in terms of the configuration of the toner used, and it is expected that the above-described problems caused by the inclusion of the magnetic material can be avoided.

As a non-magnetic one-component developing method, an electrophotographic powder toner containing a binder resin, a colorant and a charge controlling agent as essential components has been used.

At this time, a polyester resin is often used as the binder resin because it is necessary to ensure the stability of charging and the durability during continuous printing. However, the demands on the market for durability in continuous printing are increasing, and it has been difficult to obtain a toner that sufficiently satisfies these characteristics.

In particular, when an image is formed using a conventional non-magnetic one-component toner and a developing device for a non-magnetic one-component toner having a toner conveying member, a toner layer thickness regulating member and the like, an image is formed in an early stage of development. Although a good toner thin layer is formed on the toner conveying member and a good image can be obtained, an image having fog and streaks is formed when used continuously for a long time.

This is because, when the developing process is repeated continuously for a long time, the toner is partially fused onto the toner layer thickness regulating member and the toner conveying member due to friction between the toner and the toner layer thickness regulating member, and the toner is uniformly dispersed. A toner layer cannot be formed,
This is because charging of the toner becomes uneven. For this reason, when fogging occurs or the fused toner gradually increases,
It is considered that an image with streaks is formed.

In order to ensure good fluidity and good charging characteristics, the non-magnetic one-component toner contains a relatively large amount of inorganic oxide fine particles such as silica as compared with the two-component developer toner. Additives as main components are externally added, but if continuous printing is performed for a long time, external additives that are not attached to the base toner and are free will adhere to the toner layer thickness regulating member and the toner conveying member. As a result, there is a problem called filming in which a streak image is generated or the image adheres to a latent image carrier such as a photoreceptor to cause a decrease in image density.

The non-magnetic one-component developing method includes a contact type developing method in which a developing roller, which is a developer carrying member carrying a toner, is brought into contact with a photosensitive member having an electrostatic latent image to perform development.
There is a non-contact type non-magnetic one-component developing method in which a gap is provided between a developing roller and a photoreceptor, and toner on the developing roller flies and is developed. The contact-type non-magnetic one-component developing method is compared with the non-contact one-magnetic one-component developing method in that the toner on the developing roller comes into contact with the photoreceptor, thereby causing streak-like image defects and fogging due to filming. Therefore, stricter quantitative control of external additives is required. The present invention provides a toner which is effective in a contact type and non-contact type non-magnetic one-component developing method, and particularly provides a toner which is effective in a non-contact type non-magnetic one-component developing method.

[0018]

SUMMARY OF THE INVENTION An object of the present invention is to provide a toner layer thickness regulating member, a toner carrier,
There is no fusion of the toner to the toner conveying member, the charge imparting member, etc., and a good toner thin layer is formed on the developing roll. Therefore, even when used for a long time, the image density is less reduced, and no fogging or streaking occurs. An object of the present invention is to provide a non-magnetic one-component toner having excellent durability and capable of obtaining a good image.

Further, by defining the type and more preferably the amount of the abrasive, and further defining the characteristics and more preferably the amount of the inorganic fine particles to be added, the toner particles and the inorganic particles in the non-magnetic one-component developing method can be determined. An object of the present invention is to prevent fine particles from adhering and sticking to each member of a developing device without generating an excessive amount of polishing.

[0020]

Means for Solving the Problems The present inventors have made intensive studies to solve the above problems, and as a result, have reached the present invention. That is, in order to solve the above-mentioned problems, the present invention further provides a toner particle containing at least a binder resin, a colorant, and a charge control agent, further having a volume average primary particle size of 20 nm.
The following first inorganic fine particles, and a volume average primary particle size of 30 nm or more
An object of the present invention is to provide a non-magnetic one-component toner comprising: 1 μm second inorganic fine particles; and fine particles containing cerium oxide as an essential component and at least one other rare earth element compound.

The first inorganic fine particles and the second inorganic fine particles described in the present invention are indispensable for adding fluidity of toner particles, enabling uniform charging over a long period of time, and obtaining a uniform image without fog. This is particularly important in a non-magnetic one-component developing method in which a uniform thin layer needs to be formed on a developer carrying member by a charging member such as a film thickness regulating member.

In the present invention, a defect on a formed image caused by the addition of inorganic fine particles indispensable for ensuring the fluidity, or the adhesion of toner particles to a member or the like caused by a charging process of a non-magnetic one-component developing system is determined by an abrasive. Is improved by controlling the strength of the polishing property by avoiding the disadvantages caused by the addition of an abrasive.

The particles described in the present invention, which contain cerium oxide as an essential component and at least one other rare earth element compound, are fixed to the toner surface, and the toner particles themselves have a low abrasive power with a controlled abrasive power. Give.

In the following description, “particles containing cerium oxide as an essential component” or “particles containing cerium oxide as a main component” mean “cerium oxide as an essential component and at least one other rare earth element compound. Containing Particles "
Means

Since the surface hardness of the toner particles on which the inorganic particles as the abrasive are fixed substantially increases as described above, the toner particles adhere to these members by friction with the charging member and the film thickness regulating member. In addition to the fact that the toner particles are polished, they have an effect of removing toner particles that are about to adhere. In addition, since the polishing force is weak, the members of the developing device such as the charging member, the film thickness regulating member, and the photoreceptor are not damaged even in long-term continuous use.

The external addition of such an abrasive does not damage the charging member or the film thickness regulating member peculiar to the non-magnetic one-component developing method, if the polishing force is appropriately controlled, without damaging them. It is possible to prevent the adhesion of inorganic particles such as toner particles and silica, but also to the photoreceptor etc., it is also possible to prevent the adhesion of the toner particles to the photoreceptor etc. Can also be prevented at the same time. However, in order to prevent the toner particles and the inorganic fine particles from sticking to the charging member, the film thickness regulating member, and the photosensitive drum surface, which is particularly susceptible to damage, at the same time, the polishing power of the abrasive used must be precise. Control is needed.

The inventors control the polishing power of the abrasive by using an easily controllable abrasive that does not have too high a polishing power, and by appropriately adjusting the particle size and the amount of addition. In particular, it has been found that the use of fine particles containing the above cerium oxide as an essential component and further containing at least one other rare earth element compound can suitably control the polishing power.

Further, in order to reduce the adhesion of toner particles, inorganic fine particles and the like to each member of the original developing device, for example, when silica is used as the first and second inorganic fine particles, Si atoms or Ce particles are used. It has been found that it is effective to keep the atomic release rate low.

In order to reduce the liberation rate of Si atoms, it is important to add only necessary and sufficient silica to impart fluidity to the toner particles and not to add an excessive amount.
By using together the first inorganic fine particles having a volume average primary particle diameter of 20 nm or less and the second inorganic fine particles having a volume average primary particle diameter of 30 nm to 1 μm, the first inorganic fine particles can be efficiently attached to the surface of the toner particles, In addition, since the silica is not buried for a long time, the fluidity can be maintained for a long time. For this reason, it is possible to reduce the amount of free Si atoms as a result without adding an excessive amount of added silica.

Further, the second inorganic fine particles such as silica having a large particle diameter function to prevent the embedding of the first inorganic fine particles and also act as a weak abrasive. Cerium oxide added as an abrasive has a large particle size, so the amount of addition cannot be increased, and the adhesion of toner particles on the surface is not strong, but the second inorganic fine particles having a smaller particle size than cerium oxide are toner particles. It firmly adheres to the surface and replenishes the polishing power of cerium oxide over a long period of time as a milder abrasive. However, the main function of the second inorganic fine particles is only to prevent embedding of silica or the like in the first inorganic fine particles, and the second inorganic fine particles alone have a weak abrasive power as an abrasive, and may be used as a charging member or a film thickness regulating member. Cannot be completely removed.

Further, it has been found that the addition of a certain amount of fluororesin fine particles can reduce the adhesion of toner particles and inorganic fine particles per se, so that it is effective to use them together with the above-mentioned abrasive. When such an anti-adhesion treatment is performed,
Since the amount and extent of the adhesion itself can be reduced, the adhesion can be sufficiently prevented by a polishing agent such as cerium oxide having a weak polishing force, and each member of the developing device is not unnecessarily exposed to wear. Further, since the amount of filming itself caused by the fine particles of the fluororesin can be reduced, it can be prevented by a polishing agent such as cerium oxide having a gentle polishing force.

The structure of the non-magnetic one-component toner of the present invention will be described below. In the present invention, the average particle diameter of the particles means an average primary volume particle diameter unless otherwise specified.

As the binder resin used in the present invention, any resin can be used without particular limitation as long as it is a resin which is conventionally known and used as a non-magnetic one-component toner. Any commonly used binder resin can be used as the binder resin generally used. For example, polystyrene, styrene- (meth) acrylate copolymer, styrene-butadiene copolymer, polyester resin, epoxy resin, butyral resin, xylene resin, cumarone indene resin and the like can be mentioned. The binder resin may be used alone or in combination of two or more.

To make the effect of the present invention more effective,
Among them, a polyester resin is preferably used. Glass transition temperature (Tg) of polyester resin used in the present invention
Is preferably 55 ° C. or higher.
Is preferably 55 to 85 ° C. The softening point of the polyester resin used in the present invention is 90 ° C.
Above all, those having a range of 100 ° C to 180 ° C are preferable, and those having a range of 110 ° C to 160 ° C are more preferable. When the softening point is lower than 90 ° C., the toner is liable to cause a cohesion phenomenon, which is likely to cause trouble during storage or printing. In particular, when the toner is used for a non-magnetic one-component toner, the toner tends to be partially fused to the toner layer thickness regulating member, and image defects such as black stripes are likely to occur. On the other hand, when the softening point exceeds 180 ° C., the fixability deteriorates.

The polyester resin can be obtained, for example, by subjecting a polybasic acid containing a dicarboxylic acid and a polyhydric alcohol to ester condensation as essential components. Of course, as the polybasic acid and the polyhydric alcohol, an ester-forming derivative may be used, and a transesterification reaction may be carried out and used.

The specific method of obtaining the polyester resin is not particularly limited, and can be easily synthesized by known condensation polymerization in a solution. However, as a polyhydric alcohol, a diol component and a polybasic acid are used. And, if necessary, a compound having three or more carboxylic acids and two or more epoxy groups as a crosslinking agent. In the epoxy compound, one epoxy group reacts with a carboxyl group or a hydroxyl group to generate a secondary hydroxyl group, and this hydroxyl group further reacts with another carboxyl group. That is, since one epoxy group acts as a divalent group, a compound having two or more epoxy groups functions as a crosslinking agent having four or more valences.

When crosslinking is performed using such an epoxy compound, the degree of freedom in designing the thermal properties of the polyester resin is increased, so that fusion to a charging member or the like is reduced, and low-temperature fixing property, anti-offset property, It is possible to design a resin that also has weather resistance and is more preferable.

The diol component for obtaining the polyester resin includes, for example, ethylene glycol, propylene glycol, butanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, hexanediol, neopentyl glycol, cyclohexanedimethanol, hydrogenated bisphenol A, Examples thereof include a propylene oxide adduct of bisphenol A and an ethylene oxide adduct of bisphenol A.

The diol component for obtaining the polyester resin includes, for example, ethylene glycol, propylene glycol, butanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, hexanediol, neopentyl glycol, cyclohexanedimethanol, hydrogenated bisphenol A, a propylene oxide adduct of bisphenol A, an ethylene oxide adduct of bisphenol A, and the like.

Examples of the dicarboxylic acid component include maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid, phthalic anhydride, terephthalic acid, isophthalic acid, orthophthalic acid, hexahydrophthalic anhydride, and tetrahydrophthalic anhydride. , Cyclohexanedicarboxylic acid,
Examples include methylcyclohexanedicarboxylic acid, succinic acid, malonic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, mesaconic acid, metaconic acid, and glutaconic acid. Of course, these anhydrides and lower alkyl esters can also be used.

Examples of the trivalent or higher carboxylic acid component include trimellitic acid, toluene carboxylic acid, cyclohexanetricarboxylic acid, naphthalenetricarboxylic acid, and the like.
Examples thereof include tricarboxylic acids such as butanetricarboxylic acid and the like, tetra (methylenecarboxyl) methane, and tetracarboxylic acid of pyromellitic acid. Of course, these anhydrides and lower alkyl esters can also be used.

Examples of the dicarboxylic acid component include maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid, phthalic anhydride, terephthalic acid, isophthalic acid, orthophthalic acid, hexahydrophthalic anhydride, and tetrahydrophthalic anhydride. , Cyclohexanedicarboxylic acid,
Examples include methylcyclohexanedicarboxylic acid, succinic acid, malonic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, mesaconic acid, metaconic acid, and glutaconic acid. Of course, these anhydrides and lower alkyl esters can also be used.

Examples of the two or more epoxy compounds used in the present invention include bisphenol A type epoxy resin, cresol novolak type epoxy resin, phenol novolak type epoxy resin, ethylene glycol diglycidyl ether, glycerin triglycidyl ether,
One or more compounds selected from trimethylolpropane triglycidyl ether, trimethylolethane triglycidyl ether, pentaerythritol tetraglycidyl ether, hydroquinone diglycidyl ether, semi-dry or dry fatty acid ester epoxy compounds, and the like.

Specifically, examples of the bisphenol A type epoxy resin include, for example, Epicron 840,850,855,857, D-591,860,900,10 manufactured by Dainippon Ink and Chemicals, Inc.
50,1055,2055,3050,4050,4055,7050,7051, HM-091, HM-10
1 and the like. Examples of ortho-cresol novolak epoxy resins include Dainippon Ink and Chemicals, Inc.
Epicron N-660, N-665, N-667, N-670, N-673, N-680, N
-690, N-695 and the like. Examples of the phenol novolak type epoxy resin include, for example, Epicron N-740, N-770, N-775, N-865 manufactured by Dainippon Ink and Chemicals, Inc.

Among these, it is preferable to use a polyvalent epoxy compound having more than 5 epoxy groups in one molecule, since the crosslinking density of the resin is increased.

Polyester resins using polybasic acids and / or polyhydric alcohols having an aromatic ring are preferred because of their good blocking resistance. In some cases, a polyester resin obtained by reacting a polyol with a polycarboxylic acid containing an aromatic tricarboxylic acid or a derivative thereof can also be used.

The polyester resin can be obtained by performing a dehydration condensation reaction or a transesterification reaction using the above-mentioned raw material components in the presence of a catalyst, if necessary. The reaction temperature and reaction time at this time are not particularly limited, but are usually 150 to 300 ° C. and 2 to 24 hours.

In carrying out the above reaction, other components such as an esterification catalyst and a transesterification catalyst for promoting the reaction, such as magnesium acetate, zinc acetate, manganese acetate, lead acetate, antimony trioxide, germanium oxide, zinc oxide, Stannous oxide, dibutyltin oxide, dibutyltin dilaurate, and the like can be used as appropriate.

The acid value (AV) of the polyester resin is preferably 15 mgKOH / g or less from the viewpoint of improving the moisture resistance of the toner. The weight average molecular weight (Mw) of the polyester resin is preferably about 5,000 to 1,000,000. The number average molecular weight (Mn) is 300
About 0 to 20,000 is preferable.

As the colorant used in the present invention, various non-magnetic organic pigments and inorganic pigments can be used. Specifically, for example, carbon black, aniline blue, calcoyl blue, chrome yellow, ultra Marine blue, Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue,
Malachite green oxalate, lamp black, rose vengara, disazo yellow, quinacridone red, pigment red 122, C.I. I. Pigment Yellow 97, C.I. I. Pigment Blue 15, C.I. I. Pigment Yellow 180 and the like, and one kind or a combination of two or more kinds can be used.

Examples of the carbon black include Mogal L, ELFTEX 8 (above, manufactured by Cabot Corporation, USA), and MA100 (manufactured by Mitsubishi Chemical Corporation).

In the toner of the present invention, the weight ratio of the binder resin to the colorant is not particularly limited, but is usually 1 to 60 parts by weight, preferably 3 to 30 parts by weight of the colorant per 100 parts by weight of the binder resin. .

As the charge control agent used in the present invention,
For example, heavy metals such as nigrosine dyes, quaternary ammonium salts, trimethylethane dyes, salicylic acid metal complex salts, benzyl acid metal complex salts, copper phthalocyanine, perylene, quinacridone, azo pigments, metal complex salt azo dyes, and azochrome complexes. Known charge control agents such as acid dyes can be used.

In the present invention, the content of the charge controlling agent is preferably 0.5 to 3 parts by weight in total per 100 parts by weight of the solid content of the binder resin (A).

In the present invention, the average primary particle diameter is 20
nm or less of inorganic particles (hereinafter referred to as first inorganic fine particles)
Use As the first inorganic fine particles, various materials conventionally used as a fluidity improver can be used. For example, silica, alumina, titanium dioxide,
Zinc oxide, magnesium oxide and the like can be used alone or in combination of two or more. A particularly preferred first inorganic fine particle is silica. Among them, colloidal silica surface-treated with a hydrophobizing agent is preferable. The surface treatment with such a hydrophobizing agent is for preventing a change in toner charge amount due to the influence of humidity, and the degree of hydrophobicity is desirably 60% or more, more preferably 80% or more.

As the hydrophobizing agent, conventionally used hydrophobizing agents such as a silane coupling agent, a titanate coupling agent, and a silicone oil are used. Preferably, a silicon-based oil or a silane-based coupling agent is used. Examples of silane coupling agents include, for example, trimethylsilane, trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, benzyldimethylchlorosilane, methyltrimethoxysilane, methyltriethoxysilane, isobutyltrimethoxysilane , N-hexyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, hydroxypropyltrimethoxysilane, hexamethyldisilazane, hexaethyldisilazane, diethyltetraethyldisilazane, hexaphenyldisilazane, hexatoldidi Silazane or the like can be used. As the silicone oil, for example, dimethylpolysiloxane, methylhydrogenpolysiloxane, methylphenylpolysiloxane and the like can be used. The hydrophobizing agent may be treated by a conventionally known method at an amount used to achieve a degree of hydrophobicity of 60% or more, more preferably 80% or more.

In the present invention, if the average primary particle diameter of the first inorganic fine particles exceeds 20 nm, the effect as a fluidity improver decreases, and a large amount of inorganic fine particles is required to obtain a desired fluidity. In the present invention, the content of the first inorganic fine particles is 0.2 to 2% by mass with respect to the toner particles.
Preferably, the content is 0.2 to 1.5% by mass. If the content is less than 0.1% by mass, desired fluidity cannot be obtained, and printing unevenness and fogging occur, which is not preferable. If the amount exceeds 2% by mass, the released matter adheres to the toner layer regulating member or the like, which is not preferable because the toner sticks or the toner easily scatters.

The second inorganic fine particles having an average primary particle diameter of 30 nm to 100 nm contained in the developer of the present invention include:
Titania, alumina, silica, barium titanate, zinc oxide and the like can be used. Particularly preferred is silica. In the present invention, the second inorganic fine particles have a function of preventing the first inorganic fine particles from being embedded in the toner particles.

In the external addition step, the inorganic fine particles and the like are mechanically fixed to the surface of the toner particles using a mixing stirrer or the like. However, when only the first inorganic fine particles are externally added, the inorganic fine particles are It is embedded inside and does not work effectively. On the other hand, when the external addition step is performed in the presence of the second inorganic fine particles having a large particle diameter, the embedding of the first inorganic fine particles is suppressed and the first inorganic fine particles are present on the surface. In particular, even during long-term continuous operation, the first inorganic fine particles such as silica are not buried, and the fluidity can be maintained for a long time.

In the present invention, like the second inorganic fine particles, it is preferable to use those which have been surface-treated with the above-mentioned hydrophobizing agent.

In the present invention, the content of the second inorganic fine particles is preferably from 0.32 to 2.0% by mass, more preferably from 0.32 to 1.5% by mass, based on the toner particles.

The content of the second inorganic fine particles is 0.32% by mass.
In the following, the function of preventing the first inorganic fine particles from being embedded in the toner particles is not sufficiently exhibited, and the first inorganic fine particles of 20 nm or less are buried in the toner. As a result, the effect of the originally small particle diameter of the first inorganic fine particles as a fluidity improver is not exhibited, and the printing durability becomes short, which is not preferable. Also,
If the content exceeds 2.0% by mass, as described above, loosened materials and aggregates adhere to the toner layer regulating member, and adversely affect images such as streaks during printing.

The inorganic fine particles such as silica need to be fixed without being buried in the surface of the toner particles. Conversely, even if fixed on the surface, if they are weakly fixed, they are easily detached, and the detached particles are easily removed. Adhesion occurs on members of the developing device. If the adhesion is slight, it is removed by an abrasive mainly composed of cerium oxide.However, since the polishing power itself cannot be increased to avoid abrasion of the member, the inorganic fine particles are firmly fixed to the toner surface in advance. It is important to keep. Since the inorganic fine particles efficiently and firmly adhere to the toner particle surface by performing the external addition step of the above two kinds of inorganic fine particles, free S
Since i-atoms can be reduced and adhesion to members is reduced, the burden on the abrasive can be reduced.

Further, if inorganic fine particles such as silica are not effectively fixed on the surface of the toner particles, the fluidity of the toner particles is impaired. Therefore, in each step of toner supply, film formation on a carrier, cleaning, etc. Uneven distribution of toner particles is apt to occur, and local abrasion of the member due to the abrasive is likely to occur.

In the present invention, in addition to the first inorganic fine particles and the second inorganic fine particles, fine particles containing cerium oxide as an essential component and at least one other rare earth element compound are contained. In the present invention, the fine particles containing cerium oxide as an essential component and at least one other rare earth element compound include particles containing cerium oxide as an essential component and at least one of rare earth elements such as lanthanum, neodymium, and praseodymium. It is preferred that

Specifically, for example, a fine powder such as a mixture of oxides of a plurality of rare earth elements containing cerium or a multi-component oxide made of a plurality of rare earth elements containing cerium is used. The average particle diameter of the particles containing at least one rare earth element such as lanthanum, neodymium, praseodymium and the like as an essential component in the present invention is 0.05 to 5 μm, preferably 0.3 to 3 μm.
μm, particularly preferably in the range of 0.4 to 2.0 μm. When the average particle diameter is less than 0.05 μm, the polishing power as an abrasive is small, and the effect of the present invention cannot be sufficiently obtained. If the average particle size exceeds 5 μm, the photosensitive member, the developing roller and the toner layer regulating member may be damaged, which is not preferable.

In the present invention, particles containing cerium oxide as an essential component and at least one of the other rare earth element compounds have a gentler polishing effect than alumina, so that particles for the toner layer regulating member can be used. While effectively preventing toner sticking and filming on the photoconductor surface, it is possible to suppress shaving of the photoconductor accompanying printing. In the case of using alumina, since the polishing force is large, the range of the content in which the balance between the fixing of the toner to the toner layer regulating member and the filming on the photoreceptor surface and the shaving of the photoreceptor accompanying the printing is narrowed, Quantitative control is difficult and not preferable.

In the present invention, as described above, a fine powder containing cerium oxide as an essential component and at least one of rare earth elements such as lanthanum, neodymium, and praseodymium is preferable. This is because lanthanum, neodymium, and praseodymium are produced together with cerium in the natural world, so there is an economical reason that separation and purification are costly and undesirable. Relative to cerium alone, as in the present invention, when containing a fine powder containing at least one rare earth element such as lanthanum, neodymium, praseodymium,
The same effect can be obtained with a smaller amount.
The content of cerium oxide contained as an essential component in the present invention is 40% to 70%, preferably 45%.
~ 60%. Such examples include, for example, commercially available products such as MIRAKE E and MIRAKE T (Mitsui Metal Mining Co., Ltd.)
ROX M-1 and ROX M-3 (manufactured by Tohoku Metal Chemical Co., Ltd.).

In the present invention, the above-mentioned cerium oxide is used as an essential component, and particles containing at least one of rare earth elements such as lanthanum, neodymium, praseodymium and the like having an average particle size in the range of 0.4 μm to 1.0 μm are used. It is particularly preferred that

In the present invention, the content of the fine powder containing cerium oxide as an essential component and at least one of rare earth elements such as lanthanum, neodymium, and praseodymium in the toner powder is 0.1% by mass or less. It is 5% by mass, preferably 0.3 to 3% by mass. Content is 0.1
When the content is less than 5%, the polishing effect is not sufficient. On the other hand, when the content is more than 5%, the fluidity of the toner is reduced, and phenomena such as print unevenness and fogging occur, thereby deteriorating the image quality.

In the present invention, the degree of liberation of silica and cerium oxide particles was measured by using a particle analyzer PT1000 manufactured by Yokogawa Electric Corp.
It can be known by measuring the atomic release rate. It is desirable that the release rate of both Si atoms and Ce atoms is 0%, but in practice, it is 10% or less, and more preferably 7% or less. Note that the liberation rate (%) of Si atoms is (count number of Si atoms that are asynchronously emitted with C atoms) ÷ (C
Numerical value represented by (number of counts of Si atoms synchronized with atoms + number of counts of Si atoms asynchronous with C atoms) × 100. The release rate (%) of Ce atoms is (count number of C atoms and Si atoms of asynchronous emission) ÷ (C
It is a numerical value represented by (the count number of Si atoms that emit light synchronously with atoms + the count number of Si atoms that are asynchronous with C atoms) × 100.

The magnitude of the liberation rate of each atom corresponds to the magnitude of the ratio of the inorganic fine particles containing each atom which are not fixed to the surface of the toner particles and exist as single particles, and the magnitude relationship corresponds to the magnitude. Can be used as an index relating to the amount of inorganic fine particles present.

In the present invention, various auxiliaries such as a charge controlling agent and a release agent can be added in any step of the production.

In the present invention, a lubricant can be used, if necessary, for the purpose of preventing toner particles and silica from adhering to the photoconductor and damaging the photoconductor. Examples of such lubricants include those known and used in toners. For example, metal soap, zinc stearate, fine particles of fluorine-based resin and the like can be suitably used. As the fluorine resin, polyvinyl fluoride, polyvinylidene fluoride,
Polyethylene trifluoride, Polytetrafluoroethylene, Polyethylene trifluoride chloride, Ethylene trifluoride-ethylene copolymer, Ethylene tetrafluoride-ethylene copolymer, Ethylene tetrafluoride-propylene hexafluoride Polymers, fluoropolymers such as ethylene tetrafluoride-perfluoroalkyl vinyl ether and elastomers or propylene hexafluoride-vinylidene fluoride copolymer, ethylene tetrafluoride-propylene copolymer, ethylene tetrafluoride-perfluorovinyl Resin fine particles such as a fluoroelastomer such as an alkyl ether copolymer are exemplified. The particle size of the fluororesin powder is preferably 1 μm or less.

In the heat roll fixing application, various waxes are used as necessary as an auxiliary agent for enhancing the releasing effect, for the purpose of preventing troubles due to toner adhesion to the heat roll (offset). Natural wax such as wax, high pressure polyethylene, polyolefin wax such as polypropylene,
Silicone wax, fluorine wax and the like can be used.

Suitable waxes include, for example, Viscol 660P, Viscol 550P, Viscol 330
P, TP-32 (manufactured by Sanyo Chemical Industries, Ltd.), Mitsui High Wax NP505, P200, P300, P4
00 etc. The viscosity of the wax used in the present invention is 50.
~ 5000 mPa · s is preferred. Wax viscosity is 50mP
When the value is less than a · s, the toner easily adheres to the developing roller or the blade, and a defective image such as a black streak easily occurs. On the other hand, when the viscosity of the wax is 5000 mPa · s or more, dispersion in the binder resin becomes poor, the offset resistance becomes poor, and the effect of the present invention cannot be sufficiently obtained.

The toner of the present invention can be obtained by any known and customary production method. For example, a binder resin and a colorant are melt-kneaded at a temperature equal to or higher than the melting point (softening point) of the binder resin and then pulverized. Can be obtained by classification. Of course, it may be manufactured by other methods.

The coloring agent may be previously subjected to a flushing treatment so as to be uniformly dispersed in the resin, or a master batch melt-kneaded with the resin at a high concentration. Specifically, for example, the binder resin, the colorant, and the charge control agent are mixed as essential components by a kneading means such as a two-roll, three-roll, pressure kneader, or a twin-screw extruder. At this time, the colorant may be uniformly dispersed in the binder resin, and the conditions for the melt-kneading are not particularly limited, but are usually from 80 to 180 ° C. for 10 minutes to 2 hours.

In kneading, for example, the binder resin, the colorant and the release agent are mixed with 1 to 10% by weight of the colorant, 0.5 to 5% by weight of the release agent, and the balance with the binder resin and the charge control agent. What is necessary is just to prepare beforehand.

Then, after cooling, the mixture is finely pulverized by a pulverizer such as a jet mill and classified by an air classifier or the like. The average particle diameter of the toner particles is 1
~ 15 µm is preferred.

The toner of the present invention can be made more powdery by externally adding a first inorganic fine powder, a second inorganic fine powder, particles containing cerium oxide as main components and, if necessary, a lubricant to the toner particles. Body fluidity and the like can be improved, which is practically suitable.

As a method of externally adding the silica to the toner particles, for example, a conventional powder mixer such as a Henschel mixer or a so-called surface modifier such as a hybridizer can be used. The external addition may be such that silica adheres to the surface of the toner particles, or a part of the silica may be embedded in the toner particles.

The toner obtained by the present invention allows the toner to pass between the developing roller and the charging member pressed against the developing roller, and frictionally charges the toner to form an electrostatic latent image formed on the surface of the photoreceptor. Can be particularly effectively used in a contact-type non-magnetic one-component developing method for developing a toner. As the non-magnetic one-component developing method, a known and commonly used method can be adopted.For example, the toner conveyed by the toner carrier is frictionally charged by a layer thickness regulating member and its layer thickness is regulated, so that the toner is transported like a photoconductor. And a method of developing an electrostatic latent image by contacting or non-contacting the electrostatic latent image carrier.

In the present invention, the layer thickness regulating member needs to be a metal capable of frictionally charging the developer when passing through a gap with a developer carrier described later. Examples of the type of metal include aluminum, copper, and stainless steel. Among them, stainless steel is preferred because it has both good durability and charge-imparting properties.

The toner of the present invention can be fixed on a recording medium by a known and common fixing method, but exhibits more excellent performance in a pressure fixing type printer using a heat roll. As the heat roll at this time, a roll having an outermost layer made of a fluororesin or a silicone resin can be used because it is usually excellent in heat resistance and releasability.

[0086]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention includes the following inventions and embodiments.

1. At least, toner particles containing a binder resin, a colorant, and a charge control agent, further, first inorganic fine particles having an average primary volume particle size of 20 nm or less, and second inorganic fine particles having an average primary volume particle size of 30 nm to 1 μm, A particle containing cerium oxide as an essential component and at least one other rare earth element compound.

2. The rare earth element of the rare earth element compound is mainly one of lanthanum, neodymium and praseodymium.
2. The non-magnetic one-component developing toner according to the above item 1, which is at least one kind.

3. The content of the particles containing cerium oxide as an essential component is from 0.3 to 3 parts by weight based on 100 of the toner particles, and the liberation rate of Ce atoms is 10% or less. Non-magnetic one-component developing toner.

4. The binder resin has a glass transition temperature of 55.
A polyester resin having a softening point of 90 to 180 ° C and a softening point of 90 to 180 ° C.
The non-magnetic one-component developing toner as described in the above.

5. 5. The non-magnetic one-component developing toner according to any one of the above items 1, 2, 3, and 4, wherein the first inorganic fine particles and the second inorganic fine particles are colloidal silica subjected to a surface treatment with a hydrophobizing agent.

6. The content of the first inorganic fine particles is 0.2 to 2% by weight with respect to the toner particles 100, and the content of the second inorganic fine particles is 0.2 with respect to the toner particles 100.
1, 2, 3, or 2% by weight.
4. The non-magnetic one-component developing toner according to claim 4.

7. 7. The toner for non-magnetic single-component development as described in any one of the above items 1, 2, 3, 4, 5, and 6, wherein the release rate of Si atoms is 10% or less.

[0094]

The present invention will be described below in more detail with reference to Examples and Comparative Examples. In the following, numerical values in the composition table represent "parts by mass" and "% by mass", respectively. An example of the synthesis of the binder resin used for preparing the toner first is shown below.

(Resin Synthesis Example 1) Terephthalic acid 2.0 mol part Isophthalic acid 2.5 mol part Trimellitic acid 0.5 mol part Polyoxyethylene- (2.0) -2,2 4.0 mol part- In a four-necked flask equipped with a stirrer, a condenser, and a thermometer, 1.2 mol parts of bis (4-hydroxyphenyl) propane ethylene glycol was placed in a nitrogen gas stream at a flow rate of 0.1% based on all acid components.
After adding 07 parts by mass of dibutyltin oxide and removing water generated by dehydration condensation, the mixture was reacted at 220 ° C. for 15 hours. The softening temperature of the obtained polyester resin is 155 ° C. by ring and ball softening point measurement method, and T
g was 62 ° C., and the acid value was 10.

(Resin Synthesis Example 2) A polyester resin of Resin Synthesis Example 2 was produced in the same manner as in Resin Synthesis Example 1 using the following raw materials. 2.5 mole parts of terephthalic acid 2.5 mole parts of isophthalic acid 0.5 mole parts of trimethyllolpropane 3.5 mole parts of polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane Glycol 1.0 mol part The softening temperature of the resin obtained by ring-ball softening point measurement is 1
At 50 ° C., Tg by DSC was 61 ° C., and the acid value was 6.

(Example 1) 92 parts by mass of resin of Resin Synthesis Example 1 5 parts by mass of carbon black Mogal L (manufactured by Cabot Specialty Chemicals, Inc.) 1 part by mass of charge control agent Bontron S34 (manufactured by Orient Chemical Industry Co., Ltd.) Part 2 parts by weight of wax Viscol 550P (manufactured by Sanyo Chemical Industries, Ltd.) (viscosity: 150 to 250 mPa) are mixed with a Henschel mixer and kneaded with a twin-screw kneader. The kneaded material thus obtained is pulverized and classified to obtain toner powder A.

100 parts by mass of toner powder A Hydrophobic silica HDK H-2000 (manufactured by Clariant) (average primary particle size: 10 nm) 1 part by mass Hydrophobic silica NAX50 (manufactured by Nippon Aerosil Co.) 1 part by mass (average primary particle size: 30 nm) 1) Cerium oxide milleque E (manufactured by Mitsui Kinzoku Co., Ltd.) * Rare element compound content Cerium oxide 54.4% Lanthanum oxide 35.1% Praseodymium oxide 7.0% Neodymium oxide 3.4% After sieving, negatively chargeable toner A was obtained.

Example 2 A negatively chargeable toner B was obtained in the same manner as in Example 1 except that the following externally added formulation was used. Toner powder A Hydrophobic silica RY-200S (manufactured by Nippon Aerosil Co., Ltd.) 1 part by mass (average primary particle size: 16 nm) Hydrophobic silica NAX50 (manufactured by Nippon Aerosil Co., Ltd.) 1 part by mass (average primary particle size: 30 nm) Cerium oxide MIRAKE E (Mitsui Metals Co., Ltd.) 1 part by mass * Rare element compound content 54.4% cerium oxide 35.1% lanthanum oxide 7.0% praseodymium oxide 7.0% neodymium oxide 3.4% Average particle size 0.50 μm

Example 3 Toner C was obtained in the same manner as in Example 1, except that Resin Synthesis Example 2 was used instead of Resin Synthesis Example 1.

Example 4 A toner D was obtained in the same manner as in Example 1 except that the following externally added formulation was used. Toner powder A 100 parts by mass Hydrophobic silica HDK H-2000 (manufactured by Clariant) (average primary particle size: 10 nm) 1 part by mass Hydrophobic silica NAX50 (manufactured by Nippon Aerosil Co.) 1 part by mass (average primary particle size: 30 nm) Cerium oxide Mirake E (Mitsui Metals) 1 part by mass * Rare element compound content Cerium oxide 54.4% Lanthanum oxide 35.1% Praseodymium oxide 7.0% Neodymium oxide 3.4% Lubricant Fluororesin fine particles (polyvinylidene fluoride fine particles) 0.5 parts by mass Toner ED Like the toner A, the toner A exhibited negative chargeability.

Example 5 In Example 2, when the external additive was mixed with a Henschel mixer, the number of revolutions was reduced.
Toner E was manufactured by shortening the time.

Comparative Example 1 Comparative toner 1 was manufactured in the same manner as in Example 1 except that cerium oxide Mirake E manufactured by Mitsui Mining & Smelting Co., Ltd. was not used.

Comparative Example 2 Comparative toner 2 was prepared in the same manner as in Example 3 except that aluminum oxide C (average primary volume particle size: 13 nm) manufactured by Nippon Aerosil Co., Ltd. was used in place of cerium oxide Mirake E. I got

Comparative Example 3 The procedure of Example 1 was repeated, except that the hydrophobic silica HDK H-2000 manufactured by Clariant was used in an amount of 1.5 parts by mass, and the hydrophobic silica NAX50 manufactured by Nippon Aerosil was not used. Comparative toner 3
Was manufactured.

Comparative Example 4 The procedure of Example 1 was repeated, except that the hydrophobic silica HDK H-2000 manufactured by Clariant was changed to 3 parts by mass and the hydrophobic silica NAX50 manufactured by Nippon Aerosil was not used. Comparative Example Toner 4
Was manufactured.

Comparative Example 5 Comparative toner 5 was produced in the same manner as in Example 4 except that cerium oxide Mirake E manufactured by Mitsui Kinzoku Mining Co., Ltd. was not used.

With respect to the toner particles obtained in the above Examples and Comparative Examples, the thickness of the toner particles conveyed by the toner carrier is regulated by a stainless steel layer thickness regulating member, and the photosensitive member is triboelectrically charged. A printing test was carried out by using a commercially available printer using a method of developing an electrostatic latent image by contacting and facing the toner carrier, and the following items were tested.

The image density was measured using a Macbeth image densitometer RD-9.
Using No. 18, black solid portions of the image were measured at the initial stage and at every 1000 prints. The background smear was determined by subtracting the density of the white paper before printing from the density of the non-printing white background, and was defined as an average value for every 1000 sheets.

Regarding the image defect and the print life, the dedicated toner was removed from the cartridge of a commercially available printer, and the washed cartridge was filled with the toner obtained in each of the examples and comparative examples. A state in which the toner layer on the developing sleeve was uniform and no image defects occurred was determined as ○, and a case where non-uniform portions such as white spots and black stripes occurred was determined as x.

The term "print life" as used in the present invention indicates the number of sheets that can be printed without blurring the image when continuous printing is performed by filling the toner cartridge of the test developing device with the toner to be tested. . If inorganic fine particles such as silica are not efficiently added externally, the fluidity of the toner particles deteriorates, making it impossible to form a uniform thin layer of the toner powder on the carrier roll and transferring to the photoreceptor. Since the amount of waste toner not used for development increases, the print life decreases.

The release rate of Si atoms and the release rate of Ce atoms were measured under the following measurement conditions using PT1000 manufactured by Yokogawa Electric Corporation, and then applied to the above-mentioned formulas,
The release rates of Ce atoms were determined.

Tables 1 and 2 show the measurement results of the above characteristics.

[0114]

[Table 1]

[0115]

[Table 2]

In Examples 1 to 4, Si atoms and C
The release rate of e-atoms was low, and printing with good image density without background contamination and image defects was possible, and the printing life reached 10,000 sheets. On the other hand, in Example 5, the release rate of Si atoms was
Since the liberation rate of Ce atoms is high, the amount of cerium oxide adhering to the toner particles decreases, and the balance of the polishing power of the toner is lost. Although the surface hardness of the toner itself is reduced, the toner easily adheres to the charging member or the like, but the released cerium oxide particles do not adhere to the charging member due to the abrasiveness of the particles. However, light adhesion to the photosensitive drum,
It occurs with the adhesion of free silica, and a little soiling occurs. In addition, the density unevenness caused by printing was doubled.
Since the amount of silica particles on the surface of the toner particles is reduced, the fluidity of the toner particles is slightly deteriorated, and the print life is slightly reduced. However, these obstacles were within an allowable range in practical use.

Comparative Example 1 without adding cerium oxide particles
In this case, toner adhered to the charging member or the film thickness controlling member, charging was not performed uniformly, and black stripes were generated. Similarly, even in the case where cerium oxide was not added, in Comparative Example 54 in which the fluororesin particles were added, the toner particles and silica particles were prevented from adhering to the device member, but the fluorocarbon resin particles themselves did not adhere to the photoreceptor. This causes white spots in the low density area.

Further, in Comparative Example 2 in which the cerium oxide particles were replaced with aluminum oxide particles, uneven wear occurred on the charging member or the film thickness controlling member, and the charging was not performed uniformly and black stripes were generated.

Further, in Comparative Examples 3 and 4 in which only the first inorganic fine particles were added in a large amount without adding the second inorganic fine particles, the initial value was good, but the silica was buried with the printing and the silica was added. The effect is not exhibited, and the fluidity of the toner particles is reduced, fogging occurs, and the printing life is shortened.

[0120]

As described in the above embodiment, the toner of the present invention does not fuse the toner to the toner layer regulating member even if the development is continued for a long time, so that a good toner thin layer can be formed on the toner conveying member. Thus, a non-magnetic one-component toner having excellent durability and capable of obtaining a good image free from fogging and streaks even when used for a long time was obtained.

Continued on the front page F term (reference) 2H005 AA01 AA06 AA08 CA08 CA12 CA26 CB07 CB12 CB13 DA01 EA03 EA05 EA07 EA10 FA07

Claims (7)

[Claims] 1. A toner comprising at least a binder resin, a colorant and a charge controlling agent, further comprising: first inorganic fine particles having an average primary volume particle size of 20 nm or less;
A non-magnetic one-component developing toner comprising: 0 nm to 1 μm second inorganic fine particles; and particles containing cerium oxide as an essential component and at least one other rare earth element compound. 2. The non-magnetic one-component developing toner according to claim 1, wherein the rare earth element of the rare earth element compound is mainly one or more of lanthanum, neodymium and praseodymium. 3. The toner according to claim 1, wherein the content of particles containing cerium oxide as an essential component is 0.3 to 3 parts by weight based on 100 of the toner particles, and the liberation of Ce atoms is 10% or less. The non-magnetic one-component developing toner according to claim 1. 4. The binder resin has a glass transition temperature of 55 ° C. or less.
4. The non-magnetic one-component developing toner according to claim 1, wherein the toner is a polyester resin having a softening point of 90 to 180 [deg.] C. at 85 [deg.] C. 5. The non-magnetic monocomponent according to claim 1, wherein the first inorganic fine particles and the second inorganic fine particles are colloidal silica surface-treated with a hydrophobizing agent. Development toner. 6. The content of the first inorganic fine particles is 0.2 to 2% by weight based on the toner particles 100, and the content of the second inorganic fine particles is 0.2 to 2% by weight based on the toner particles 100. 2
%, By weight%.
6. The non-magnetic one-component developing toner according to 5. 7. The non-magnetic one-component developing toner according to claim 1, wherein the liberation rate of Si atoms is 10% or less.