JPH10161337A - One-component developer and image forming method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a one-component developer stabilizing the electrostatic charge and conveyance of the toner over a long period of time and giving an image having superior image quantity and to provide an image forming method using the developer. SOLUTION: This one-component developer consists of toner particles contg. a bonding resin and a colorant and an additive contg. a titanium compd. obtd. by allowing part of TiO(OH)2 produced by a wet process to react with a silane compd. and treating the resultant reactional product with a fluorine-contg. silane compd. by a dry process. The fluorine-contg. silane compd. is represented by the formula Cn F2n+1 CH2 CH2 Si(CH3 )p X3-p [where X is a hydrolyzable group, (n) is an integer of 1-10 and (p) is 0 or 1] or Cm F2m+1 -Ph-CH2 CH2 Si(CH3 )q Y3-q [where Ph is phenylene, Y is a hydrolyzable group, (m) is an integer of 1-8 and (q) is 0 or 1].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-component developer used for developing an electrostatic image in electrophotography, electrostatic recording and the like, and an image forming method using the same.

[0002]

2. Description of the Related Art In recent years, an electrophotographic dry developing system has been widely used not only in an electrostatic copying machine but also in a printer, a facsimile, and a multifunction machine of these and a copying machine. In particular, as a recent trend in these technical fields, there is a strong demand for ecological measures such as miniaturization, weight reduction, resource saving and recycling,
Improvements and new developments of an image forming method and a developer used for the method have been made.

[0003] At present, as a dry developing method in various electrostatic copying systems put into practical use, a two-component developing system using a carrier such as toner and iron powder and a one-component developing system using no carrier are known. .

[0004] The two-component development system is the most widely used system, but the toner particles adhere to the surface of the carrier to deteriorate the developer, so that a clear image cannot be maintained for a long period of time. In addition to the above problems, a toner concentration adjusting system for maintaining a constant toner concentration ratio in the developer and a mixing device for newly adding toner and developer to the developer are required. However, there is a disadvantage that the size becomes large.

Therefore, as a developing system, there has been an increasing demand for a one-component developing system, which is characterized in that the developing device is small and lightweight and there is no need for a troublesome toner concentration control system. It is becoming.
The one-component toner developing systems are classified into a magnetic one-component developing system using a magnetic toner and a non-magnetic one-component developing system using a non-magnetic toner.

In the magnetic one-component developing method, a magnetic toner is held and developed by using a developer carrying member provided with a magnetic field generating means such as a magnet therein, and the toner transport control is easy. In recent years, many of them have been put to practical use because of low internal contamination of copiers, printers and the like. However, since the magnetic toner used in the magnetic one-component developing method contains a colored magnetic substance such as black or brown such as magnetite therein, there is a serious drawback that it cannot be applied to full color, which has been increasingly required in the market in recent years. is there. Further, the magnetic one-component developing device has to include a magnet inside the developer carrier (developing roll), and therefore, there is a limit to downsizing of the developing roll. Miniaturization is not easy.

On the other hand, the non-magnetic one-component developing system can be colored because no magnetic material is used for the toner.
Since no magnet is used for the developing roll, the weight is reduced,
It is possible to reduce the size and cost. However, in the two-component developing method, there is a stable charging and transporting member called a carrier, and in the magnetic one-component developing method, there is a stable transporting and layer forming means of the magnetic force of a magnet roll. In the system, since there is no such a stable charging and conveying means, it is necessary to stably supply and hold the toner on the developing roll only by electrostatic force, and charge and develop the toner. Therefore, the non-magnetic one-component developing toner is required to have higher and more severe characteristics (rapid and uniform charging, better fluidity, etc.). That is, the non-magnetic one-component toner must be charged / conveyed within a short contact time with the blade or the sleeve, and has a higher charge and a higher charging speed (rapid charging) than a normal magnetic one-component toner or two-component toner. Rise) is required. Further, the non-magnetic one-component toner is charged mainly by contact friction with the blade / sleeve. However, if the toner component is contaminated on those charging members, the charge deteriorates like the carrier of the two-component developer. When the toner component adheres to the blade portion, a streak-like image quality defect occurs.

Therefore, in order to maintain high durability of the non-magnetic one-component toner, in addition to the above-described high charging ability and high charging speed,
The property of low adhesion is strongly required. In particular, in recent years, there has been an increasing demand for higher image quality such as color, and attempts have been made to achieve high image quality by reducing the particle size of the toner.However, when the toner particles are miniaturized, the surface area per unit weight is reduced. As a result, the above-mentioned defects become remarkable.

[0009] By reducing the particle size of the toner, it is possible to achieve a high image quality and to suppress the consumption of the toner, thereby reducing the cost per sheet. In calculation, the minimum toner weight per unit area of paper that reaches a certain image density can be reduced as the particle size of the toner is reduced, but in reality, loss occurs in the developing process and the transfer process. Then, the remaining toner is collected by the cleaner. For example, background fog on the photoreceptor is one of toner loss, and even if there is no problem in the image quality of a copied image, background fog occurs on the photoreceptor and is collected by a cleaner without being transferred. To suppress the toner consumption, it is necessary to prevent not only the image quality but also the background fog on the photoconductor.

Conventionally, in order to stabilize the charge and conveyance of toner, an inorganic oxide fine powder such as silica is added to toner particles (external addition) for the purpose of improving fluidity and chargeability.
And so on. However, although silica-based fine powders generally used are effective for improving the fluidity of the toner, they increase the charge of the negatively chargeable toner excessively under low temperature and low humidity, while on the other hand, under high temperature and high humidity. It absorbs moisture to reduce the chargeability, and there is a great difference in chargeability depending on the environmental conditions used. For this reason, the silica-based fine powder cannot ensure the toner transport property on the developer carrying member and the optimal charging property under both high-temperature, high-humidity and low-temperature, low-humidity conditions. There has been a problem that background fog, toner dripping, and further, contamination inside the apparatus are caused.

In order to solve these problems, it is known to add an inorganic fine powder which has been subjected to a specific surface treatment to toner particles, for example, to add a silica fine particle whose surface has been subjected to a hydrophobic treatment. ing. However, simply adding the inorganic fine powder subjected to these treatments to the toner particles does not provide sufficient chargeability. In particular, when a polyester resin is used as the binder resin, no effect is obtained. For example, in a case where sufficient chargeability can be ensured in operation under high temperature and high humidity, under low temperature and low humidity, the toner is excessively charged and the toner transport amount on the developer roll becomes excessive,
Further, there is a drawback that the charging becomes broader and the developing performance is reduced and the fog ratio is increased.

In particular, as described above, since the non-magnetic one-component toner is not provided with a stable conveying means and a layer forming means, the toner is stably supplied and held on the developer roll only by electrostatic force. In addition, it is necessary to charge and develop, and on top of that, it is necessary to charge by abrasion in a short contact time and a small space between the sleeve of the developing roll and the charging blade. Speed is strongly required. However, the toner to which silica fine particles are externally added usually has a slow rise in charging. Therefore, in the case of a non-magnetic one-component toner, fog due to the opposite polarity toner and toner cloud (in-machine contamination) can be obtained even at a low temperature and a low humidity at which a high charge can be obtained. ) Is liable to occur. In particular, when used for a long period of time, the toner component adheres to the blade portion and cannot be transported uniformly, so that the image quality deteriorates due to streaks on the image, and furthermore, the background fog and the toner , And in-flight contamination occurs. This phenomenon causes the same problem when using silica treated with a low surface energy substance silicone oil as described in JP-A-61-277964.

The fine silica powder has a broad charge distribution on the developer roll mainly due to high resistance, high chargeability, slow charging speed, and the like, and the charge amount falls within an appropriate range. However, fogging and contamination in the machine due to generation of the opposite polarity toner are caused. As described above, at present, the silica fine particles have not been improved in terms of the environmental dependency of charging, the charging speed, and the poor charging distribution of the silica, even if a hydrophobic treatment, a negative charging relaxation treatment, etc. are performed. ,
In addition, the problem of reducing the adhesion to the charging member has not been improved.

Next, titania added to toner particles in order to improve the chargeability and fluidity of the toner has a sharp charge distribution since the rise of charge is faster than silica and the resistance is lower than that of silica. There is a feature. However, a toner using titania as an external additive does not provide high charge, and is liable to cause a decrease in toner transport amount, a decrease in density reproducibility due to a decrease in charge, and background fog. In order to improve the chargeability, a method has been proposed in which hydrophobic titanium oxide is externally added to a toner (JP-A-58-216252, JP-A-60-123682, and JP-A-60-2388).
No. 47). This hydrophobic titanium oxide is obtained by treating the surface with a silane compound, a silane coupling agent, silicone oil, or the like. According to this method, the chargeability can be improved more than the untreated hydrophilic titania, and it is used for two-component toners and magnetic one-component toners, and is actually on the market.

However, in the case of non-magnetic one-component toner, a constant charge amount can be improved depending on the type and amount of the processing agent, but the charge amount is still not at a satisfactory level and the environmental dependency is limited. There is. In addition, when the degree of hydrophobicity of titanium oxide is increased by using a treating agent, the charging level and the environmental dependency are certainly improved as compared with the conventional hydrophilic titanium oxide, but, on the contrary, the charging speed and the charging of titanium oxide have. The fact is that the sharpness of the distribution is significantly lower than that of conventional titanium oxide.

Titanium oxide is obtained mainly by extracting titanium oxide crystals from ilmenite ore by a sulfuric acid method or a hydrochloric acid method. The crystals are purified by a wet method, heated, and calcined. To be obtained, a chemical bond generated by dehydration condensation naturally exists, and it is not easy to re-disperse such aggregated particles. In particular, titanium oxide extracted as fine powder
Due to the formation of secondary and tertiary aggregation, the effect of improving the fluidity of the toner is significantly inferior to that of silica. In particular, when the particle size of the toner is reduced, the adhesion between particles is further increased,
This phenomenon becomes more remarkable because the fluidity of the toner is further deteriorated. Also, conventionally used titanium oxide has a higher specific gravity than silica, or cannot be firmly attached to the toner surface, and is easily peeled off from the toner surface.
It is inferior in long-term charging stability accompanied by sleeve contamination, and is liable to cause contamination of the photoreceptor, resulting in image quality deterioration and image quality defects.

Next, in order to improve the fluidity of the toner and to achieve the environmental dependency of electrification, a combination of hydrophobic titanium oxide and hydrophobic silica has been proposed as an external additive (Japanese Patent Application Laid-Open No. 60-1985). -136755). According to this technique,
Although the disadvantages of hydrophobic silica and hydrophobic titanium oxide are temporarily suppressed, they are easily affected by one of the additives depending on the dispersion state, and the dispersion structure on the toner surface is particularly important for ensuring durability. Is difficult to control stably, and when stress is applied on the sleeve, defects of either hydrophobic silica or hydrophobic titanium oxide are likely to appear, and therefore, those defects are stably controlled over a long period of time. It was difficult.

Next, a method has been proposed in which hydrophobic amorphous titanium oxide is added to toner particles (Japanese Patent Laid-Open No. Hei 5 (1993) -205).
204183, JP-A-5-72797).
Amorphous titanium oxide can be obtained by hydrolyzing a metal alkoxide or a metal halide using a CVD method (Chemical Engineering Transactions, Vol. 18, No. 3,
Pp. 303-307 (1992)). However, although titanium oxide obtained by such a hydrolysis method can achieve both the charging characteristics and the improvement of the fluidity of the toner, it has a large amount of adsorbed water inside the particles. Will remain. That is, since amorphous titanium oxide has a strong adhesive force to the photoreceptor, only the amorphous titanium oxide remains on the photoreceptor without being transferred. There are drawbacks such as scratching.

Further, as a method for purifying titanium oxide by a wet method, a silane compound is hydrolyzed in an aqueous medium, and the titanium oxide is subjected to a surface treatment using the hydrolyzed compound to take out the titanium oxide in a state where aggregation is suppressed. And a method of adding the obtained titanium oxide to toner particles (Japanese Unexamined Patent Application Publication No.
No. 188633). When the silane compound is treated by this method, the fluidity of the toner is improved because the number of agglomerated particles is reduced as compared with the conventional method of hydrophobizing titanium oxide. It's no different from
The high negative chargeability and environmental dependency are insufficient, and further, the charge speed (admixability of the additional toner) and the charge distribution are adversely affected.

Further, when the above-mentioned inorganic oxide is added to the surface of the toner and used continuously for a long period of time, stress is applied to the toner by the layer-forming member or the like, and toner filming and fusion occur on the layer-forming member. Since the chargeability of the toner changes due to peeling or embedding of the additive, it becomes difficult to maintain stable charge and transport of the toner for a long period of time. In order to solve these problems, a specific binder resin is used to prevent the embedding of an external additive (JP-A-6-95429 and JP-A-6-95429).
JP-A-102699, JP-A-6-266156, etc.) and the use of specific charge control agents or external additives (JP-A-6-51561, JP-A-6-20824).
No. 2, JP-A-6-250442, etc.) have been proposed. However, none of these methods is sufficient. In particular, in a full-color developing system in which four colors are superimposed, it is necessary to more precisely control the amount of toner development.

As described above, in the one-component developer,
Many problems still remain for long-term stabilization of the charge amount and transport amount of the toner, and there are also many problems in image formation using the same.

[0022]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and aims to solve the problems. That is, the first object of the present invention is to stabilize charging and transport of toner for a long time,
An object of the present invention is to provide a one-component developer capable of obtaining a stable image density. A second object of the present invention is to provide a one-component developer in which low developability, fog, and the like do not appear for a long period of time, and filming and fusion hardly occur. Further, a third object of the present invention is to provide an image forming method using a one-component developer which can stably obtain excellent image quality over a long period of time.

[0023]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on one-component developers in order to solve the above-mentioned problems, and as a result, as a toner particle additive, a part of a specific titanium compound was converted to silane. After reacting with the compound, furthermore, by using the titanium compound obtained by treating with a specific fluorine-containing silane compound, a clear image without change in image density, fog and filming can be obtained for a long time. The present invention was found to be obtained stably over the entire range, and the present invention was completed.

That is, the one-component developer of the present invention comprises toner particles containing a binder resin and a colorant, and an additive,
The additive reacts a part of TiO (OH) ₂ prepared by a wet method with a silane compound, and further treats with a fluorine-containing silane compound represented by the following formula (1) or (2) by a dry method. It is characterized by containing the titanium compound obtained by the above. _{C n F 2n + 1 CH 2} CH 2 Si (CH 3) p X 3-p (1) ( wherein, X represents a hydrolyzable group, n represents an integer of 1 to 10, p is 0 or 1 _{there.) C m F 2m + 1} -Ph-CH 2 CH 2 Si (CH 3) q Y 3-q (2) ( wherein, Ph is a phenylene group, Y represents a hydrolyzable group, m is 1 In addition, in the image forming method of the present invention, a thin layer of the developer is formed on the developer carrying member, transported to the developing section, and the formed thin layer is formed. A developing step of developing the electrostatic latent image of the latent image holding member using the toner layer. As the developer, toner particles containing a binder resin and a coloring agent, and TiO (O
H) reacting a part of ₂ with a silane compound, and further adding an additive containing a titanium compound obtained by treating with a fluorine-containing silane compound represented by the above formula (1) or (2) by a dry method. Characterized in that a one-component developer is used.

In the present invention, the titanium compound used as an additive of the one-component developer preferably has a specific gravity in the range of 2.8 to 3.6, and has an average primary particle diameter of 10 to 3.6. It is preferably in the range of 70 nm.
The one-component developer is preferably added in an amount of 0.1 to 5.0 parts of an additive to 100 parts of the toner particles, and the binder resin used for the toner particles may include a polyester resin. preferable. The one-component developer of the present invention is
It is preferably used as a non-magnetic one-component developer, and particularly preferably used in a multicolor image forming method.

[0026]

Embodiments of the present invention will be described below in detail. The one-component developer of the present invention forms a thin layer of the developer on a developer carrier, transports the obtained thin layer of the developer to a developing unit, and forms an electrostatic latent image on a latent image holding member. The latent image forming step of forming an electrostatic latent image on at least the latent image holding member, the thin layer formed on the developer carrying member A developing step of developing the latent image on the latent image holding member using a developer, a transferring step of transferring a developer (toner) image on the latent image holding member to a transfer member, and heat fixing of the toner image on the transfer member Fixing step.

In the latent image forming step, a conventionally known method can be applied, and an electrostatic latent image is formed on a latent image holding member of a photosensitive layer or a dielectric layer by an electrophotographic method or an electrostatic recording method. is there. The latent image holding member used in the present invention is a conventionally known member in which a photosensitive layer is formed on a cylindrical support, and the cylindrical holding member is formed by extruding aluminum or an aluminum alloy, followed by surface processing. And a photosensitive layer formed of a known material such as an organic or amorphous silicon is used as the photosensitive layer.

In the developing step, a developer carrier (developing roll)
On a rotating cylinder, a toner is formed in a thin layer with an elastic blade or the like, and the toner is transported to a developing unit, and a developing roll and a latent image holding member that holds an electrostatic latent image are contacted or fixed at the developing unit. The electrostatic latent image is developed with toner while a bias is applied between the developing roll and the latent image holding member. The developer carrier used in the present invention may be an elastic sleeve such as silicone rubber, a sleeve from which a metal or ceramic such as aluminum, SUS stainless steel, nickel, or the like is pulled out, or a substrate surface for controlling the transportability and chargeability of the toner. Oxidation or metal plating,
Surface treatment such as polishing and blasting, coating with resin, etc., especially aluminum, SU
When a sleeve from which a metal such as S stainless steel or nickel or a ceramic is drawn is used, the effect of the present invention is remarkably improved because long-term charging properties can be obtained by reducing toner adhesion to the sleeve.

To form a toner layer on a developing roll,
This is performed by bringing an elastic blade into contact with the sleeve surface. As the material of the elastic blade, it is preferable to use a rubber elastic material such as silicone rubber or urethane rubber, and a material obtained by adding or dispersing an organic or inorganic substance in the elastic material to control the toner charge amount may be used.

In the transfer step, the toner image on the latent image holding member is transferred to paper as a transfer member. As the transfer unit in the present invention, a known type such as a contact type in which a transfer roller is pressed against a latent image holding member and a non-contact type using a corotron are used. Type is commonly used. The cleaning process is
The toner remaining on the latent image holding member without being transferred in the transfer step is removed by a cleaner. As a cleaning unit in the present invention, a known device such as blade cleaning or roller cleaning is used. An elastic rubber such as silicone rubber or urethane rubber is used for the blade cleaning. The fixing step is to fix the toner image transferred to the transfer body by a fixing device. As a fixing means, a heat fixing method using a heat roll is usually used.

The one-component developer according to the present invention comprises toner particles containing at least a binder resin and a colorant and an additive, and the additive is TiO (OH) ₂ obtained by a wet method. Is reacted with a silane compound, and then the obtained reaction product is treated with a fluorine-containing silane compound represented by the following formula (1) or (2) by a dry method to obtain a titanium compound. And the titanium compound has a specific gravity of 2.8.
It is preferably in the range of -3.6. _{C n F 2n + 1 CH 2} CH 2 Si (CH 3) p X 3-p (1) ( wherein, X represents a hydrolyzable group, n represents an integer of 1 to 10, p is 0 or 1 _{there.) C m F 2m + 1} -Ph-CH 2 CH 2 Si (CH 3) q Y 3-q (2) ( wherein, Ph is a phenylene group, Y represents a hydrolyzable group, m is 1 In the formulas (1) and (2), the hydrolyzable group represented by X or Y may be any functional group that decomposes with water. However, a halogen atom such as a chlorine atom and an alkoxyl group such as a methoxy group and an ethoxy group are particularly preferable.

In general, the production method of titanium oxide by a usual wet method is produced by a chemical reaction in a solvent, and is divided into a sulfuric acid method and a hydrochloric acid method. Among them, in the sulfuric acid method, the following reaction proceeds in a liquid phase, and insoluble TiO (OH) ₂ is obtained by hydrolysis. FeTiO ₃ + 2H ₂ SO ₄ → FeSO ₄ + TiOSO
₄ + 2H ₂ O TiOSO ₄ + 2H ₂ O → TiO (OH) ₂ + H ₂ SO
_{4 In} the hydrochloric acid wet method, chlorination is first performed in the same manner as in the dry method to produce titanium tetrachloride, which is then dissolved in water and hydrolyzed while adding a strong base to TiO (OH). ₂ ) is obtained. This is represented by the following chemical formula. TiCl ₄ + H ₂ O → TiOCl ₂ + 2HCl TiOCl ₂ + 2H ₂ O → TiO (OH) ₂ + 2HCl

Further, in the usual titanium oxide production process, washing with water and filtration are repeated thereafter, followed by firing to obtain titanium oxide. If necessary, further crush,
After pulverization, the same treatment as in the silane compound is performed. However, the conventional production method of this titanium oxide is T
Since the bonds between i are strong, there is a serious disadvantage that the particles sinter in the firing step and a large number of agglomerations occur. In order to solve this problem, many efforts have been made to strengthen wet pulverization, to react with a treating agent before drying, and the like. However, at present, it is impossible to disintegrate this agglomeration into primary particles. Even if the thus obtained titanium oxide is applied to the additive of the toner particles and the coverage on the toner particles is secured in combination with the silica particles, the same fluidity as in the case of using silica cannot be obtained. Also, photoreceptor flaws and filming due to the aggregation will occur.

The titanium oxide obtained by the conventional manufacturing method is
There is a limit to the amount that can be treated by using a silane compound. In general, when the amount of the silane compound is increased, the charge-imparting ability is increased. However, the ability reaches the limit at a treatment amount of about 15 to 20% by weight with respect to titanium oxide.
Therefore, when the amount of the coupling agent is increased in order to impart high charge, not only high charge cannot be obtained, but also excess coupling agent reacts with each other to further increase agglomerated particles. When added to the toner particles, the charging speed is reduced, the charging distribution is broadened, and the like. As described above, the conventionally used titanium oxide has many agglomerated particles and does not have satisfactory levels of high charging ability, low charging speed and charging distribution.

The titanium compound used in the present invention is obtained by reacting a silane compound with TiO (OH) ₂ produced in the above-mentioned wet process, and then drying it.
In this method, there is no high-temperature firing step of several hundred degrees,
Since no strong bond between titanium occurs, there is no aggregation,
The particles can be taken out in the form of substantially primary particles, and in addition, this titanium compound allows a large amount of treatment because a silane compound can be directly reacted with TiO (OH) ₂ .

Further, the limit value of the treatment amount contributing to the charging ability of this titanium compound is higher than that of the conventionally treated titanium oxide, and even if it depends on the particle size of the raw material, it is about three times as large as that of the conventional product. (50% to 70% of the original titanium)). Therefore, the charge of the toner can be controlled by the treatment amount of the silane compound. It can be greatly improved.
In addition, since the excess silane compound can be reduced, the reaction between the silane compounds decreases, and even when the processing amount is increased, high charge can be obtained without lowering the charge speed and charge distribution.

Further, since the titanium compound transfers little to the sleeve and there is no transfer of the processing agent, there is little contamination of the sleeve, and the toner charge on the developer carrier does not change over a long period of time. There is no adhesion on the body, and no image quality defect occurs for a long time. This is because the titanium oxide used (specific gravity: 2.8 to 3.6) adheres firmly to the surface of the toner because it is lighter than conventional ones. This is because the silane compound to be treated does not desorb and the reaction between the silane compounds to be treated is small (it adheres firmly to the raw material) so that the transfer of the treating agent is small.

The titanium compound used in the present invention is a titanium compound obtained by treating the above-mentioned titanium compound with a fluorine-containing silane compound represented by the following formula (1) or (2). _{C n F 2n + 1 CH 2} CH 2 Si (CH 3) p X 3-p (1) ( wherein, X represents a hydrolyzable group, n represents an integer of 1 to 10, p is 0 or 1 _{there.) C m F 2m + 1} -Ph-CH 2 CH 2 Si (CH 3) q Y 3-q (2) ( wherein, Ph is a phenylene group, Y represents a hydrolyzable group, m is 1 An integer of to 8 and q is 0 or 1.) By treating with the above-mentioned fluorine-containing silane compound,
Adhesion of external additives and / or toner particles to the charging member blade is greatly reduced, no streaking due to poor transport, excellent density reproducibility over a long period of time, and no fog on the image. Image quality can be obtained.

The fluorine-containing silane compound is made of TiO
When a silane compound is reacted with (OH) ₂ and treated by a wet method at the same time, the treatment becomes unstable because the fluorine-containing silane compound is not uniformly dispersed in the liquid layer. Therefore, TiO (OH) ₂ was previously reacted with a silane compound by a wet method, dried, and then treated by a dry method, thereby enabling uniform treatment with a fluorine-containing silane compound. Here, a titanium compound obtained by reacting a silane compound with TiO (OH) ₂ has lower cohesiveness than other titanium oxides, so that re-aggregation due to the treatment of the fluorine-containing silane compound does not occur. Thereby, the charge distribution of the toner is further sharpened,
Background fog on the photoreceptor can be reduced over a long period of time.
In the present invention, among the titanium compounds obtained by the above treatment, those having an average primary particle diameter of 100 nm or less,
Preferably, those having a range of 10 to 70 nm are used.

Recent developers tend to have a smaller particle size in response to a demand for higher image quality. However, in order to improve transfer failure due to an increase in adhesive force caused by the smaller particle size of the toner particles. The silica or titania having a large particle diameter used in the present invention may be added as a second external additive (transfer aid) in the present invention. In addition, by using the large-diameter titania, low charge, environmental dependency, and decrease in admixability (broadening of charge distribution in a long-term run) caused by using a second external additive, and further processing Good transferability can be obtained without deteriorating the charge providing ability due to long-term stress due to peeling of the agent.

The treatment with the fluorine-containing silane compound represented by the general formula (1) or (2)
It is carried out in the range of 0.1 to 80 parts by weight, more preferably 1 to 50 parts by weight, per 100 parts by weight. When the fluorine-containing silane compound is used in an amount of 0.1 parts by weight or less, if used for a long period of time, streak-like image quality deterioration due to blade contamination of the toner occurs, and background fog, which is considered to be due to the low chargeability of the streaks, is generated. It is assumed that the blade adhesion preventing effect obtained by the treatment with the fluorine-containing silane compound is due to the presence of the fluorine-containing silane compound in the outermost surface layer of the titanium compound.

In the present invention, in addition to the fluorinated silane compounds represented by the formulas (1) and (2), chlorosilanes, alkoxysilanes, silazanes, Special silylating agents can be used. Specifically, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, tetraethoxysilane, Methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltrimethoxysilane, decyltrimethoxysilane, hexamethyldisilazane, N, O-bis (trimethylsilyl) acetamide, N, N-bis (Trimethylsilyl) urea, ter
t-butyldimethylchlorosilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyl Examples include, but are not limited to, trimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, and γ-chloropropyltrimethoxysilane.

The amount of the silane compound used is TiO (O
H) Depending on the primary particle size of the bulk of ₂ ), generally T
10 to 80 parts by weight per 100 parts by weight of iO (OH) ₂
It is in the range of parts by weight, more preferably 20 to 50 parts by weight. If the amount used is less than 10 parts by weight, the treatment function with the silane compound cannot be exhibited, while if the amount used exceeds 80 parts by weight, the excess silane compound becomes oily and the fluidity of the toner is inferior. Occurs. However,
The reaction treatment with the silane compound is intended to impart a high charge to the toner, improve the environment dependency, improve the fluidity of the toner, reduce the interaction within the photosensitive material, and reduce the blade adhesion during long-term use. The processing amount is appropriately adjusted by comprehensively examining the particle size and surface area of the used toner particles, developer carrier, and TiO (OH) ₂ raw material.

The amount of the additive (titanium compound) added to the toner particles varies depending on the particle size of the toner particles, the composition of the developer carrier, and the like. 0.1 to 5.0 parts by weight, preferably 0.2 to 2.0 parts by weight. If the amount is less than 0.1 part by weight, the fluidity of the toner becomes insufficient.
Exceeding 0 parts by weight may cause an increase in the fixing temperature and a decrease in the fixing strength in the fixing process, and may impair the color development of the superimposed base color due to a decrease in light transmittance when used in full color. become.

In the developer of the present invention, as the toner particles, known toner particles comprising a binder resin and a colorant as main components are used. As the binder resin, styrene, styrenes such as chlorostyrene, ethylene, propylene, butylene, monoolefins such as isoprene, vinyl acetate, vinyl propionate,
Vinyl esters such as vinyl benzoate and vinyl butyrate, methyl acrylate, ethyl acrylate, butyl acrylate,
Dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate,
Α-methylene aliphatic monocarboxylic esters such as butyl methacrylate and dodecyl methacrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl butyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropenyl ketone , A homopolymer or a copolymer thereof. Examples of particularly typical binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, and styrene-acrylonitrile. Copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyethylene, polypropylene and the like, and further, polyester, polyurethane, epoxy resin, silicone resin, polyamide,
Modified rosin, paraffin wax and the like can be mentioned.

Colorants used in the toner include carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow, methylene blue chloride,
Phthalocyanine blue, malachite green oxalate, lamp black, rose bengal, C.I. I. Pigment Red 48: 1, C.I. I. Pigment Red 1
2: 2, C.I. I. Pigment Red 57: 1, C.I.
I. Pigment Yellow 97, C.I. I. Pigment
Yellow 12, C.I. I. Pigment Blue 15: 1,
C. I. Pigment Blue 15: 3 and the like can be exemplified as typical examples.

A charge controlling agent may be added to the one-component developer in the present invention, if necessary. As the charge control agent, known ones can be used, but high-molecular-weight polymers such as a copolymer containing maleic acid as a monomer component, and a metal-containing dye such as a fluorine-based surfactant, a salicylic acid metal complex, and an azo-based metal compound. Acids, quaternary ammonium salts, azine dyes such as nigrosine, carbon black, charge control resins, etc. are used. In particular, a salicylic acid complex of Zn or Al metal or a quaternary ammonium salt is 0.1 to 10% by weight. It is preferable to use within the range.

Further, a releasing agent may be added to the developer in order to improve the offset resistance. The release agent used is preferably a paraffin having 8 or more carbon atoms, polyolefin, or the like. Examples thereof include paraffin wax, paraffin latex, microcrystalline wax, and the like, and polypropylene, polyethylene, and the like. These may be used alone or in combination. However, the amount of addition is preferably in the range of 0.3 to 10% by weight. Further, as the particle diameter of the developer, it is preferable to use those having a volume average particle diameter in the range of 3 to 15 μm, more preferably 5 to 10 μm.
It is in the range of μm. When the volume average particle diameter is less than 3 μm, the fluidity is remarkably reduced, so that it is impossible to form a layer satisfactorily, causing fogging and dirt.
Above, the resolution is reduced and high image quality cannot be obtained.

The developer of the present invention can be produced by any known method, but is particularly preferably produced by a kneading and pulverizing method. That is, the binder resin and the colorant are melt-kneaded using a kneader such as a kneader or an extruder, and then cooled, pulverized, and added to the toner particles obtained by classification. A method of mixing and producing is preferred.

In the present invention, the titanium compound is added to the toner particles and mixed. The mixing can be performed by, for example, a V-type blender, a Henschel mixer, a Loedige mixer or the like. At this time, various additives may be added as necessary. Examples of such additives include other fluidizing agents, cleaning aids for polystyrene fine particles, polymethyl methacrylate fine particles, polyvinylidene fluoride fine particles, and the like, or transfer aids. Agents and the like. Further, if necessary, using a vibration sieving machine, a wind sieving machine, etc.,
Coarse particles of the toner may be removed.

The charge amount of the developer in the present invention was measured after stirring 30 g of 100 μm iron powder and 1.2 g of toner with a turbula mixer for 60 seconds using a blow-off charge amount measuring device manufactured by Toshiba Chemical Corporation. . The measurement was performed at a temperature of 22 ° C./humidity of 55% RH. The particle size of the toner is measured using a particle size analyzer T
AII was measured at an aperture diameter of 100 μm. The specific gravity of the titanium compound used in the present invention was measured using a Le Chatelier pycnometer in accordance with JIS-K-0061, 5-2-1. The operation method is as follows. (1) Put about 250 ml of water into a Le Chatelier pycnometer,
Adjust so that the meniscus is at the scale position. (2) The specific gravity bottle is immersed in a thermostatic water bath, and the liquid temperature is 20.0 ± 0.
When the temperature reaches 2 ° C., the position of the meniscus is accurately read on the scale of the pycnometer (accuracy: 0.025 ml). (3) Approximately 100 g of a sample is weighed to the order of 1 mg, and its mass is represented by W. (4) Place the weighed sample in a pycnometer to remove bubbles. (5) The specific gravity bottle is immersed in a constant temperature water bath, and the liquid temperature is adjusted to 20.0 ±
While maintaining the temperature at 0.2 ° C., the position of the meniscus is accurately read on the scale of the pycnometer (accuracy: 0.025 ml). (6) The specific gravity is calculated by the following equation. D = W / (L ₂ −L ₁ ) S = D / 0.9982 [where D is the density of the sample (20 ° C.) (g / cm ³ );
S: Specific gravity of sample (20/20 ° C.), W: Apparent mass (g) of sample, L ₁ : Meniscus reading (20 ° C.) (ml) before putting sample in specific gravity bottle, L ₂ : Sample Meniscus reading after placing in pycnometer (20 ° C.) (ml). Note that 0.9982 in the above formula means the density of water at 20 ° C. (g / cm ³ ).

[0052]

EXAMPLES 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.

In the present invention, titanium oxide produced by a wet method, that is, titanium oxide produced by a sulfuric acid method and a hydrochloric acid method can be used. Here, ilmenite ore is used as the titanium oxide, and To separate iron powder, and hydrolyze the obtained TiOSO ₄ to form TiO
A wet sedimentation method for producing (OH) ₂ was used.

What is important in this method is hydrolysis and dispersion adjustment for forming nuclei and washing with water. In particular, pH adjustment (acid neutralization) and slurry concentration adjustment in the dispersion treatment are carried out by using a titanium compound. Therefore, a high level of control is required.

[Preparation of Additives for Toner Particles] (Preparation of External Additive A)
H) ₂ 100 parts of isobutyl trimethoxysilane 40
The components are mixed and reacted by heating at 35 ° C. After that, wash with water,
After filtration and drying at 120 ° C., 100 parts of the produced titanium compound is spray-dried on a fluorine-containing silane compound [structural formula: CF ₃ CH ₂ CH ₂ Si (OC
H _{3) 3]} was treated with 10 parts, to obtain an average primary particle size 45nm by solving the soft aggregation pin mill, a titanium compound A in the specific gravity 3.2. (Adjustment of External Additive B) In the external additive A, the average primary particle diameter was 20 nm and the specific gravity was 3.20 in the same manner as the external additive A, except that the pH adjustment and the dispersion adjustment were changed to adjust the particle diameter. Thus, 1 titanium compound B was obtained. (Adjustment of external additive C) Same as external additive A, except that the addition amount of isobutyltrimethoxysilane was changed to 30 parts and the addition amount of the fluorine-containing silane compound was changed to 30 parts. Titanium compound C having an average primary particle size of 40 nm and a specific gravity of 3.1 was obtained by a suitable method. (Adjustment of external additive D) Same as external additive A, except that the addition amount of isobutyltrimethoxysilane was changed to 50 parts and the addition amount of the fluorine-containing silane compound was changed to 5 parts. Average primary particle diameter 35 nm, specific gravity 3.
Thus, a titanium compound D was obtained.

(Preparation of External Additive E) An external additive A was prepared in the same manner as the external additive A, except that isobutyltrimethoxysilane was replaced with decyltrimethoxysilane. 0.3 of titanium external additive E was obtained. (Adjustment of external additive F) In the external additive A, the fluorine-containing silane compound was replaced with another fluorine-containing silane compound [structural formula: C ₈
F ₁₇ CH ₂ CH ₂ Si (OCH ₃ ) ₃ ], except that the average primary particle size was 40 n.
m, a titanium compound F having a specific gravity of 3.2 was obtained.

(Preparation of External Additive G)
iO (OH) ₂ was washed with water, filtered, and calcined at 700 ° C. to obtain titanium oxide having an average primary particle size of 30 nm. Thereafter, the mixture is pulverized by a jet mill, and then dispersed in water. In 100 parts of titania, 40 parts of isobutyltrimethoxysilane and a fluorine-containing silane compound [structural formula: CF ₃ CH ₂ CH]
₂ Si (OCH ₃ ) ₃ ] was mixed, wet-pulverized with a sand grinder, stirred with a kneader, and dried by heating to obtain an external additive G (specific gravity: 3.9). (Adjustment of external additive H) TiO (OH) produced by the above method
₂ was washed with water, filtered and calcined at 700 ° C. to obtain titanium oxide having an average primary particle size of 40 nm. Thereafter, the mixture is dispersed in toluene and wet-pulverized by a sand grinder, and then 100 parts of titania is added to a fluorine-containing silane compound [structural formula:
C ₈ F ₁₇ CH ₂ CH ₂ Si (OCH ₃ ) ₃ ], 30 parts of this were stirred, heated and dried, and further crushed by a jet mill to remove the external additive H (specific gravity: 3.9). Obtained.

(Preparation of External Additive I)
100 parts of iO (OH) _{2 and} 40 parts of decyltrimethoxysilane are mixed and reacted by heating. Thereafter, the resultant was washed with water and filtered, and soft aggregation was released at 120 ° C. to obtain a titanium compound having an average primary particle size of 40 nm and a specific gravity of 3.2. (Adjustment of external additive J) TiO (OH) produced by the above method
₂ 100 parts, 40 parts of decyltrimethoxysilane and a fluorine-containing silane compound [Structural formula: C ₈ F ₁₇ CH ₂ CH ₂ S
i (OCH ₃ ) ₃ ] and heat-react. Thereafter, the resultant was washed with water and filtered to dissolve the soft aggregates at 120 ° C. to obtain a titanium compound having an average primary particle size of 35 nm and a specific gravity of 3.1.

[Production of Toner Particles] (Production of Toner Particles X) Binder resin (polyester resin, Mw = 17000, Tg = 66 ° C.) 95 parts Phthalocyanine pigment (blue 15: 3) 5 parts After mixing, the mixture was melted and kneaded by a Banbury mixer, cooled, finely pulverized by a jet mill, and further classified by a classifier,
Thus, toner particles X having an average particle size of 7.5 μm were obtained. The charge amount of the obtained toner particles X was -9 μc / g.

(Production of Toner Particles Y) Binder Resin (Polyester Resin Mw = 25000, Tg = 68 ° C.) 91 parts Carbon Black (BP1300, manufactured by Cabot) 6 parts Charge control agent (Bontron E88, manufactured by Orient Chemical Industries, Ltd.) 3 parts) After mixing the above materials with a Henschel mixer, melt-kneading with a Banbury mixer, cooling the mixture, finely pulverizing with a jet mill, and further classifying with a classifier,
Thus, toner particles Y having an average particle size of 9.5 μm were obtained. The charge amount of the obtained toner particles Y was −15 μc / g.

[Image Forming Apparatus] FIG. 1 is a schematic sectional view of an image forming apparatus used for image quality evaluation in the present invention. In FIG. 1, a photosensitive drum 1 and a developing roll 3 are arranged so as to have a fixed gap, and the photosensitive drum 1 is charged by a roll charger 2 and then exposed to laser light to form an electrostatic latent image. The electrostatic latent image was developed by superimposing an AC voltage and a DC voltage on the developing roll 3 and the developer supply roll 4. The silicone rubber layer forming blade 5 was brought into contact with the developing roll 3 at a constant linear pressure to form a thin layer of toner. The peripheral speed of the photosensitive drum 1 is set to 60 mm / sec.
The peripheral speed of the developing roll 3 was 90 mm / sec. A roll transfer device 6 was used for transferring the toner, and a blade type cleaner 7 was used for cleaning. Alumite was used as a material for the developing roll 3.

Example 1 100 parts by weight of the toner particles X and 1.0 part by weight of the external additive A were mixed using a Henschel mixer, and sieved with a wind sieving machine at 106 μm to obtain a developer 1. Example 2 A developer 2 was obtained in the same manner as in Example 1 except that the external additive A was replaced with the external additive B. Example 3 A developer 3 was obtained in the same manner as in Example 1 except that the external additive A was replaced with the external additive C. Example 4 A developer 4 was obtained in the same manner as in Example 1 except that the external additive A was replaced with the external additive D.

Example 5 A developer 5 was obtained in the same manner as in Example 2 except that the toner particles X were replaced with the toner particles Y. Example 6 A developer 6 was obtained in the same manner as in Example 5 except that the external additive B was replaced with the external additive E. Example 7 A developer 7 was obtained in the same manner as in Example 5 except that the external additive B was replaced with the external additive F.

Comparative Example 1 A developer 8 was obtained in the same manner as in Example 1 except that the external additive A was replaced with the external additive G. Comparative Example 2 A developer 9 was obtained in the same manner as in Example 1, except that the external additive A was replaced with the external additive H. Comparative Example 3 A developer 10 was obtained in the same manner as in Example 1, except that the external additive A was changed to amorphous titanium having a particle size of 30 nm.

Comparative Example 4 A developer 11 was obtained in the same manner as in Example 1 except that the external additive A was replaced with silica fine particles having a particle diameter of 12 nm treated with silicone oil. Comparative Example 5 A developer 12 was obtained in the same manner as in Example 5, except that the external additive B was changed to silica fine particles having a particle diameter of 16 nm treated with hexamethyldisilazane. Comparative Example 6 A developer 13 was obtained in the same manner as in Example 5, except that the external additive B was replaced with the external additive H. Comparative Example 7 A developer 14 was obtained in the same manner as in Example 1 except that the external additive A was replaced with the external additive I. Comparative Example 8 A developer 15 was obtained in the same manner as in Example 1 except that the external additive A was replaced with the external additive J.

Using the developers 1 to 15 obtained in the above Examples and Comparative Examples, an image was formed using the image forming apparatus shown in FIG. 1 in a high temperature and high humidity environment of 30 ° C. and 85% RH. And 10 ° C, 30% RH in a low-temperature and low-humidity environment.
A print test of 10,000 sheets was performed. Table 1 shows the results.

[0067]

[Table 1]

[Toner Flow Characteristics * 1] The toner flowability was evaluated using an off-line auger dispenser (target dispensing amount ≧ 700 mg / sec). The evaluation criterion was evaluated as ○ when 700 or more, and × when less than 700. [Initial charge amount * 2] The toner is transported on a sleeve, left in each environment for 24 hours, and measured by a suction tribo-measurement method in each environment, and the charge amount after 10,000 copies is similarly measured. did. [Comprehensive electrification evaluation * 3] Environmental difference = {initial electrification amount (high temperature / high humidity / low temperature / low humidity) + Electrification amount after running 20,000 sheets (high temperature / high humidity / low temperature / low humidity)} × 1/2 Such a judgment was made. Environmental difference criterion: ○ ≧ 0.7, 0.7> △ ≧ 0.5, ×
<0.5 Maintainability = Comprehensive evaluation of charge amount at high temperature and high humidity (after 30,000 sheets initial) + low temperature and low humidity charge amount (after 10,000 sheets initial) x 1/2 Was done. Maintainability criteria: ○ ≧ 0.8, 0.8> △ ≧ 0.5, ×
<0.5 Charge distribution = Charge distribution of the toner on the sleeve after copying 30,000 sheets was measured by a charge distribution measuring device, and the value was obtained by dividing the central value of the distribution by the width of the distribution. Judgment criteria: ≧≧ 0.6, 0.6> △ ≧ 0.4, × <0.
4

[Comprehensive image quality evaluation * 4] "Fog": Sensitivity evaluation of observing the image background with a 50x magnifier. On copied image: Judgment by observation of print sample. On photoreceptor: Judge by observation after transferring the tape on the photoreceptor. “Density unevenness / transfer failure”: The solid density is determined by measuring three points (A4 upper part to lower part) with a Macbeth densitometer. "Density maintenance": Judge by measuring the image density at the initial stage and at 10,000 copies with a Macbeth densitometer. "Image quality defect": An image quality defect caused by damage to the photoconductor is visually determined. "In-machine contamination": The state of toner scattering due to toner scattering and sleeve streak is visually determined. Criteria for the above-mentioned "fog", "density unevenness / transfer failure", "density maintenance", "image quality defect" and "in-machine stain": ○ is no problem at all, △ is slightly problematic, × is considerably problematic, XX is very problematic. "Streaking": Judgment based on image quality after copying 30,000 sheets and deposits on blade. Judgment criteria: ○: image quality and blade are good, △: image quality is good, slight adhesion to blade, ×: image quality (streaks occur), both blades have problems, XX: image quality and blade adhesion are both poor .

[0070]

EFFECTS OF THE INVENTION The one-component developer of the present invention has excellent chargeability, charge speed, environment resistance and charge distribution, and also has excellent charge retention of toner on the developer carrier. In addition, the image forming apparatus using the one-component developer of the present invention has various characteristics that the sleeve contamination, the photoconductor damage and the photoconductor contamination are extremely low. It is possible to obtain excellent image quality with low developability, no background fogging on the image and the photosensitive member, and no streaks due to contamination of the charging member.

[Brief description of the drawings]

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

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Photoreceptor drum, 2 ... Roll charger, 3 ... Development roll, 4 ... Developer supply roll, 5 ... Layer forming blade, 6 ...
Roll transfer unit, 7 ... blade type cleaner.

Claims (2)

[Claims] A one-component developer comprising toner particles containing a binder resin and a colorant and an additive, wherein the additive is
Titanium obtained by reacting a part of TiO (OH) ₂ prepared by a wet method with a silane compound and further treating with a fluorine-containing silane compound represented by the following formula (1) or (2) by a dry method. A one-component developer comprising a compound. _{C n F 2n + 1 CH 2} CH 2 Si (CH 3) p X 3-p (1) ( wherein, X represents a hydrolyzable group, n represents an integer of 1 to 10, p is 0 or 1 _{there.) C m F 2m + 1} -Ph-CH 2 CH 2 Si (CH 3) q Y 3-q (2) ( wherein, Ph is a phenylene group, Y represents a hydrolyzable group, m is 1 An integer of ８8, q is 0 or 1.) 2. A process for forming a thin layer of developer on a developer carrier, transporting the thin layer to a developing unit, and developing an electrostatic latent image on a latent image holding member using the formed thin layer. In the image forming method, as the developer, toner particles containing a binder resin and a colorant and a part of TiO (OH) ₂ prepared by a wet method are reacted with a silane compound. Or an additive containing a titanium compound obtained by treating with a fluorine-containing silane compound represented by the following formula (2): _{C n F 2n + 1 CH 2} CH 2 Si (CH 3) p X 3-p (1) ( wherein, X represents a hydrolyzable group, n represents an integer of 1 to 10, p is 0 or 1 _{there.) C m F 2m + 1} -Ph-CH 2 CH 2 Si (CH 3) q Y 3-q (2) ( wherein, Ph is a phenylene group, Y represents a hydrolyzable group, m is 1 An integer of ８8, q is 0 or 1.)