JP2003098731A - Magnetic toner and image forming device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide magnetic toners with which the impartation of an electrostatic charge to the toners is sufficiently performed and good images free of image staining by the defect of cleaning can be obtained and an image forming device using the same. SOLUTION: The magnetic toners consisting of at least a binder resin and magnetic material are characterized in that the magnetic toners contain inorganic particulates treated by a silicone oil; the liberation rate of the silicone oil is 10 to 70%; the magnetization of the magnetic toners is (1) 10 to 25 emu/g in a 5 kg oersted magnetic field and (2) 7 to 20 emu/g in a 1 kg oersted magnetic field.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic toner used as a developer for developing an electrostatic latent image in electrophotography, electrostatic recording, electrostatic printing, etc., and an image forming apparatus using the magnetic toner. Regarding

[0002]

2. Description of the Related Art In electrophotography, generally, an electrostatic latent image is formed on an electrostatic latent image carrier using a photoconductive material by various means such as reflected light from a document or laser light, and then the electrostatic latent image is formed. The latent image is developed with toner, and the toner is transferred to paper or the like as required, and then fixed by heating or solvent vapor to obtain a copy image or a print image. As a means for developing an electrostatic latent image formed on an electrostatic latent image carrier such as a photoconductor, a method using a liquid developer (wet development method) and a method in which a colorant is dispersed in a binder resin are used. There is also a method (dry developing method) using a one-component type or two-component type dry developer such as a toner or a developer obtained by mixing the toner with a carrier. Although each of these methods has advantages and disadvantages, at present, the dry development method is widely used. Among these methods, the two-component dry development method is
Compared to the one-component dry development method, it can be relatively speeded up and has a long life, so it is widely used mainly in medium to high speed copying machines and printers.

In recent years, there has been a strong demand for higher definition and higher resolution of copied or printed images. To obtain such high-definition and high-resolution images, Japanese Patent Publication No. 6-8222
No. 7, Japanese Patent Publication No. 7-60273, Japanese Patent Laid-Open No. 2-8
Japanese Patent Publication No. 77 proposes a developer having a small average particle size and defining the toner particle content of 5 μm or less and its distribution. Here, the toner particles of 5 μm or less are essential components for forming a high-definition, high-resolution image,
It is said that when toner of this particle size is smoothly supplied during development of a latent image, an image that is faithful to the latent image, that is, that has excellent reproducibility without protruding from the latent image is obtained. On the other hand, the edge effect phenomenon, in which the density of the central portion of the image is lower than that of the edge portion, becomes more prominent for toner particles of 5 μm or less, but in contrast to this, for the toner particles of intermediate particle diameter of 5 μm or more, It is said that this problem can be solved by defining the number%. However, the smaller the particle size toner, the higher the definition,
5 μm, which is advantageous for forming high resolution images
When the following toner particles are contained in 17% by number, the volume% occupies only 3% by volume. It is extremely unlikely that the toner having a small particle diameter of 5 μm or less is selectively deposited on the peripheral portion on the latent image with such an amount.

On the other hand, Japanese Patent Nos. 1989625 and 212
According to Japanese Patent Publication No. 9883, the conventional magnetic toner contains 50 parts by weight or more of the magnetic substance with respect to the binder resin.
Magnetization in a magnetic field of k Oersted is greater than 20 emu / g, and the toner is difficult to develop due to the magnetic bias effect. In particular, when the toner contains a large amount of toner particles having a particle size of 5 μm or less, the toner is overcharged, so that further development Poor performance, resulting in significantly reduced image density. Further, particularly in the recent downsized developing devices, when there are many fine particles, there are drawbacks such as poor transferability from the photoconductor and insufficient cleaning. Furthermore, when these toners are used as a two-component developer with carrier particles, a phenomenon called so-called spent, in which toner that is difficult to develop accumulates on the surface of the carrier, significantly shortens the life of the developer.

In order to prevent such a spent, conventionally, a method of coating the surface of the carrier with various resins has been proposed. For example, a carrier coated with a resin such as a styrene-methacrylate copolymer and a styrene polymer has excellent charging characteristics, but has a relatively high critical surface tension on the surface, and therefore has a long life as a developer. Absent. Further, since the carrier coated with the tetrafluoroethylene copolymer has a low surface tension, the toner is less likely to be spent, but the tetrafluoroethylene copolymer is located at the most negative side in the triboelectrification series. Therefore, it cannot be used when the toner is to be negatively charged.

As a carrier having a low surface tension, a carrier coated with a coating layer containing a silicone resin has been proposed. For example, unsaturated silicone resin, organosilicone, silanol, etc. are mixed with styrene-acrial resin to coat the carrier surface (US Pat.
No. 562533), a carrier whose surface is coated with a polyphenylene resin and an organosilicone terpolymer resin (US Pat. No. 3,847,127); a styrene-acrylate methacrylate resin, and a surface coated with an organosilane, silanol, siloxane, or the like. Carrier (US Pat. No. 3,627,522); a carrier whose surface is coated with a silicone resin (JP-A-55-1).
No. 27567); and a carrier whose surface is coated with a resin-modified silicone resin (Japanese Patent Laid-Open No. 55-157751). The use of silicone resin coated carrier improves the spent resistance, but it is 5μ.
If there are many toner particles of m or less, it cannot be said that the recent demand for longer life is sufficiently satisfied.

As a method for limiting the number of toner particles of 5 μm or less, a one-component developing method is proposed in JP-A-4-124682 and JP-A-10-91000, but it determines image quality. The particle size distribution in the range where most of the toner particles are present is not described. Also, the effect is limited to the one-component developing method.

On the other hand, the one-component developing method does not use a developer in which carrier particles and toner particles are mixed as in the two-component developing method, but contains an electric force or a magnetic substance generated by friction between the toner and the developing sleeve. The toner is held on the developing sleeve by the magnetic force between the developing sleeve containing the toner and the magnet, and when the electrostatic latent image is approached, the attraction force in the latent image direction to the toner particles by the electric field formed by the electrostatic latent image is the toner. By overcoming the binding force between the particles and the developing sleeve, the toner particles are attracted and adhered onto the electrostatic latent image to visualize the electrostatic latent image. Therefore, the one-component developing method has an advantage that the developing device can be downsized because it is not necessary to control the toner concentration, but the number of toner particles in the developing area is smaller than that of the two-component developing method, and therefore, the toner on the photoconductor is reduced. The amount of toner developed on the paper was not sufficient, and it was difficult to support a high-speed copying machine.

As a method of improving these drawbacks, a two-component developing method has been devised which does not require toner concentration control, as in Japanese Patent Publication No. Hei 5-67233. In this method, the developer around the developing sleeve supplies toner. In order to charge the toner by taking the toner into the developer at a part and regulating the developer with the layer thickness regulating member, a replenishment mechanism for replenishing the toner and a sensor for detecting the toner concentration are not required. Since the amount of the developer cannot be increased as compared with the two-component developing device, in the case of a high speed machine in which the linear velocity of the developing sleeve is high, the toner cannot be sufficiently charged and the background stain occurs. Further, in order to impart sufficient charge to the toner, it is necessary to increase the regulation stress in the layer thickness regulating member, so that the toner film is formed on the carrier surface by heat generation due to collision of developer particles. There is a drawback in that the so-called “spent” occurs, the charging characteristics of the carrier deteriorate with the use time, and toner scattering, background fog, and the like occur.

Since the developer used in a small-sized developing device needs to be charged to the replenished toner in a short time, a large amount of fluid flows to the replenished toner so that the replenished toner is quickly mixed with the developer. A fluidity improver was added, but when such a developer is repeatedly used, excess fluidity improver in the toner firmly adheres to the electrostatic latent image carrier, resulting in streaky abnormal images. There was a drawback to do. Further, when the stirring stress of the developer is increased, besides the phenomenon of spent, there is a problem that a so-called charge-up phenomenon occurs in which the charge amount of the toner becomes larger than necessary. Further, since the amount of the developer is small in these small-sized developing devices, the amount of toner held by the developer is small,
When an original having a large image area is continuously copied, the amount of toner consumption increases, and the toner density in the developer changes extremely, so that the image density decreases.

Further, in this developing device, the amount of taken-in toner is different between a portion where the developer moves actively and a portion where the developer does not move, or a portion where the developer is large and a portion where the developer is small,
The toner density becomes partially unstable, and uneven image density and fogging are likely to occur. Therefore, a technique is disclosed in which two toner supply members are provided in a toner hopper and a developer is passed through a path formed by each toner supply member to solve density unevenness and fog in the longitudinal direction of the apparatus. 63
It is disclosed in Japanese Patent No. 4282. However, in the technique disclosed in the above publication, there are problems that the developing unit becomes large and the cost increases because two toner supply members are used.

Particularly in the above-mentioned developing method in which the intake of the toner is self-controlled by the movement of the developer, the particle size and the particle size distribution of the toner are important, that is, if the number of particles of 5 μm or less is large, the fluidity of the toner is increased. However, there is a drawback that the toner cannot be taken in stably. Also,
When the number of coarse particles is large, the substantial amount of toner taken in is reduced, and particularly when an image with a large toner consumption is output, the image density is lowered.

Further, a method has been proposed in which toner particles and inorganic powders such as various metal oxides are mixed and used for the purpose of improving the flow characteristics and charging characteristics of the toner, which is called an external additive. There is. If necessary, the surface of the inorganic powder may be treated with a specific silane coupling agent, titanate coupling agent, silicone oil, organic acid or the like for the purpose of modifying the hydrophobicity, charging characteristics, etc., and a specific resin may be coated. Methods for doing so have also been proposed. Known examples of the inorganic powder include silicon dioxide (silica), titanium dioxide (titania), aluminum oxide, zinc oxide, magnesium oxide, cerium oxide, iron oxide, copper oxide, tin oxide, and the like. In particular, silica fine particles obtained by reacting silica or titanium oxide fine particles with an organic silicon compound such as dimethyldichlorosilane, hexamethyldisilazane, or silicone oil to substitute silanol groups on the surface of the silica fine particles with organic groups to make them hydrophobic are used.

Further, conventionally, cleaning is performed so as to be parallel to the surface of the latent image carrier and orthogonal to the moving direction of the surface, and to protrude by a predetermined amount to a blade supporting member fixed to a casing supporting the latent image carrier. The blade is installed. Further, in order to clean the surface of the latent image carrier, in the counter direction toward the surface of the latent image carrier,
A cleaning blade is attached with the desired abutment pressure. In the cleaning device of the image forming apparatus in which the latent image carrier has a small diameter (approximately φ30 or less), the contact pressure of the cleaning blade, the cleaning angle (the contact angle of the cleaning blade with the latent image carrier), the hardness of the cleaning blade, The material of the cleaning blade, the free end length (protruding amount) of the cleaning blade, the thickness of the cleaning blade, etc. are optimized according to the linear velocity of the latent image carrier, and cleaning failure due to toner slipping or blade ridge line breakage, Conditions are set to prevent abnormal images due to noise and chatter between the photoconductors, turning of the blades, and lack of scraping performance of the blades due to adhesion of toner additives and paper dust to the photoconductor surfaces. However, as a means for achieving high image quality in recent years, the toner particle size is being reduced, and the toner particle size reduction causes an increase in the van der Waals force of the toner on the latent image carrier, and the cleaning blade. It is becoming difficult to clean the surface of the latent image bearing member only by setting the conditions.

[0015]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned drawbacks, and an object thereof is to sufficiently impart the charge to the toner and to prevent the image from being smeared due to poor cleaning. To provide a magnetic toner capable of obtaining an image and an image forming apparatus using the magnetic toner.

[0016]

In order to solve the above-mentioned problems, the invention according to claim 1 is a magnetic toner comprising at least a binder resin and a magnetic material, wherein the magnetic toner is inorganic fine particles treated with silicone oil. And the liberation rate of the silicone oil is 10 to 70%, and the magnetization of the magnetic toner is (1) 10 in a 5 k Oersted magnetic field.
˜25 emu / g and (2) 7 to 20 emu / g in a 1 k Oersted magnetic field.

According to the first aspect of the present invention, since the magnetic toner contains inorganic fine particles in which the liberation rate of silicone oil is in an appropriate range and the saturation magnetization is in an appropriate range,
By using the magnetic toner as a developer, it is possible to obtain a high-quality image free from toner scattering, transfer omission, and background stain. In particular, when the developing sleeve or the photosensitive member such as a small developing device has a small diameter and only the elastic rubber blade is used for the cleaning system, the above-described effect is great. It is estimated that these effects are due to the following reasons. If there is silicone oil that can be liberated from the external additive to an appropriate degree, a very small amount of silicone oil will be constantly supplied to the photoreceptor, etc., and its surface energy is low, so it will spread to the surface of the photoreceptor in an extremely short time, It is possible to reduce the coefficient of friction and prevent abrasion and wear of the photoconductor. Further, the adhesive force with the photoconductor is lowered, the transfer efficiency to the transfer material is increased, the residual toner on the photoconductor is reduced, the load of cleaning is reduced, and as a result, cleaning failure is suppressed and a good image without image stain can be obtained. it can.
Further, it is possible to form a high-quality image free from background stains by suppressing reverse charging and adhesion of low-charged substances due to contaminants contained in a transfer medium such as a developer or paper which causes background stains in an image.

The release rate of silicone oil defined in the present invention means the ratio (weight percentage) of free silicone oil to the total amount of silicone oil treated with inorganic fine particles. Therefore, even if the amount of free silicone oil per unit weight of the inorganic fine particles is the same, the release rate varies depending on the particle size and surface area of the inorganic fine particles. If the release rate is low, the effect cannot be exhibited, and if the release rate is too high, the adverse effect of the bulk silicone oil appears strongly. Therefore, rather than simply specifying the bulk silicone oil liquid component amount However, it is more universal in terms of its quality and compatibility.

The invention according to claim 2 is the magnetic toner according to claim 1, characterized in that the inorganic fine particles are made of silica and / or titanium oxide.

According to the second aspect of the present invention, when silica or titanium oxide is used as the inorganic fine particles, the release rate of the silicone oil can be appropriately maintained, and the magnetic toner containing the inorganic fine particles is used as the developer. By using
A higher quality image can be obtained.

According to a third aspect of the present invention, in the magnetic toner according to the first or second aspect, the particle size distribution of the magnetic toner has a weight average particle size of 6.0 to 10.0 μm and a particle size of 5 μm.
It is characterized in that the toner particles of m or less are 20 to 80% by number.

According to the invention of claim 3, the particle size distribution of the toner has a weight average particle size of 6.0 to 8.0 μm and 5 μm.
When the toner particles of m or less are 40 to 80% by number, and more preferably 40 to 60%, an image with higher definition and higher resolution can be obtained. That is, if the number of particles having a particle size of 5 μm or less is more than 80%, the fluidity of the toner is deteriorated, and the toner is not taken in smoothly, so that the image density unevenness due to the toner density unevenness is likely to occur. Further, when the number of particles of 5 μm or less is less than 40%, the number of fine particles that faithfully reproduce the latent image is reduced, and therefore, particularly when outputting a high-resolution image, the reproducibility is inferior. Further, when the number of coarse particles is large, the substantial amount of toner taken in is reduced, and particularly when an image with a large toner consumption is output, the image density is lowered. Furthermore, the weight average particle diameter of the toner is 6.0 to 8.0.
μm, and more preferably 7.0 to 8.0 μm. If the weight average particle diameter is less than 6.0 μm, the charge of the toner becomes high after long-term use, and problems such as a decrease in image density, particularly in a low humidity environment, tend to occur. When the weight average particle diameter exceeds 8.0 μm, 1200 dp
The resolution of the minute spot of i was not sufficient, and there was a large amount of scattering to the non-image portion, and the image quality tended to be inferior.

The toner particle size distribution can be measured by various methods, but in the present invention, it was measured using a Coulter counter. That is, a Coulter Counter TA-II type (manufactured by Coulter, Inc.) is used as a measuring device, and an interface (manufactured by Nikkaki) that outputs the number distribution and volume distribution
And PC9801 personal computer (NEC
1) is connected, and the electrolyte is 1
% NaCl aqueous solution is prepared. As a measuring method, a surfactant as a dispersant in 10 to 15 ml of the electrolytic aqueous solution,
Preferably the alkylbenzene sulfonate is 0.1-
5 ml was added, and 2 to 20 mg of the measurement sample was further added, and the dispersion treatment was performed for about 1 to 3 minutes with an ultrasonic disperser. Put 100 to 200 ml of electrolytic aqueous solution in another beaker, add the sample dispersion liquid to a predetermined concentration, and use the Coulter Counter TA-II type as an aperture having a 100 μm aperture as a standard.
The particle size distribution of particles of ˜40 μm is measured, the volume distribution and the number distribution of particles of 2 to 40 μm are calculated, and the weight-based weight average particle size (D4: the median value of each channel is a representative of the channels) obtained from the volume distribution. Value).

According to a fourth aspect of the present invention, only the magnetic toner according to any one of the first to third aspects, the magnetic toner and the magnetic carrier, or the magnetic toner and a coating layer containing at least a silicone resin as a main component are provided. The image forming apparatus uses a developer made of any one of magnetic carriers.

According to the invention of claim 4, since the magnetic toner according to any one of claims 1 to 3 is used as a developer, the toner is sufficiently charged.
It is possible to form a high-quality image free from image stains due to poor cleaning.

According to a fifth aspect of the present invention, in the image forming apparatus according to the fourth aspect, the cleaning is attached to the blade supporting member fixed to the casing supporting the latent image carrier so as to protrude by a predetermined amount. The blade is parallel to the surface of the latent image carrier and orthogonal to the moving direction of the surface, and further 20 g / cm to the surface of the latent image carrier in the counter direction in order to clean the surface of the latent image carrier.
It is characterized by being attached at a contact pressure of 40 g / cm.

According to a sixth aspect of the present invention, in the image forming apparatus according to the fifth aspect, the cleaning blade is installed so that the cleaning angle θ1 is 75 to 85 °.

The invention according to claim 7 is the image forming apparatus according to claim 5 or 6, characterized in that the hardness of the cleaning blade is 62 to 75 Hs (JIS-A).

The invention according to claim 8 is the image forming apparatus according to any one of claims 5 to 7, wherein the material of the cleaning blade is polyurethane rubber.

According to a ninth aspect of the present invention, in the image forming apparatus according to any of the fifth to eighth aspects, the free end length of the cleaning blade is 6 to 8 mm.

The invention according to claim 10 relates to claims 5 to 9.
In the image forming apparatus described in any one of 1 to 3, the cleaning blade has a thickness of 1.3 mm to 2.2 mm.

According to the fifth to tenth aspects of the invention, in the image forming apparatus using the magnetic toner according to the first to third aspects as a developer, the relationship between the cleaning blade and the latent image carrier is more appropriate. Since it is set, cleaning failure due to toner slipping or blade ridge line failure, squeal or chatter between the blade and the photoconductor, blade curling, toner additive or paper dust on the photoconductor surface due to insufficient scraping performance of the blade The occurrence of an abnormal image due to the adherence of is suppressed.

The invention of claim 11 relates to claims 5 to 1.
In the image forming apparatus described in any one of 0, the surface of the latent image carrier is moved at a linear velocity of 120 mm / sec to 150 mm / sec.

According to the invention of claim 11, claim 1
Since the magnetic toners described in 1 to 3 are used as a developer and the relationship between the cleaning blade and the latent image carrier is set more appropriately, the surface of the latent image carrier is 120 mm /
It is possible to form a high-quality image even with a linear velocity of sec to 150 mm / sec, and it is possible to provide an image forming apparatus having a medium or higher copying or printing speed.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The magnetic toner of the present invention is a magnetic toner comprising at least a binder resin and a magnetic material, the magnetic toner contains inorganic fine particles treated with silicone oil, and the liberation rate of the silicone oil is 10 to 70%. Yes, the magnetization of the toner is (1) 10 to 10 in a 5k Oersted magnetic field.
25 emu / g, and (2) the magnetization in a 1 k Oersted magnetic field is 7 to 20 emu / g.

As the silicone oil used in the present invention, dimethyl silicone oil, methylphenyl silicone oil, chlorophenyl silicone oil, methylhydrogen silicone oil, alkyl modified silicone oil, fluorine modified silicone oil, polyether modified silicone oil, alcohol modified. Silicone oil, amino modified silicone oil, epoxy modified silicone oil, epoxy / polyether modified silicone oil, phenol modified silicone oil, carboxyl modified silicone oil, mercapto modified silicone oil, acrylic, methacryl modified silicone oil, α
At least one selected from the group consisting of methylstyrene-modified silicone oil and the like can be used.

Examples of the inorganic fine particles of the present invention include silica, alumina, titanium oxide, barium titanate,
Magnesium titanate, calcium titanate, strontium titanate, iron oxide, copper oxide, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, red iron oxide, antimony trioxide. At least one selected from the group consisting of magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide and silicon nitride. Among them, silica and titanium dioxide are particularly preferable. The addition amount can be 0.1 to 5% by weight, preferably 0.3 to 3% by weight, based on the toner. As for those preferably used in the present invention, MOX80 (primary average particle diameter, about 30 n, manufactured by Nippon Aerosil Co., Ltd.)
m), OX50 (primary average particle diameter, about 40 nm) and T
T600 (primary average particle diameter, about 40 nm), Idemitsu Kosan Co., Ltd., IT-PB (primary average particle diameter, about 40 nm) and I
T-PC (primary average particle diameter, about 60 nm), Fuji Titanium Industry Co., Ltd., TAF110A (average particle diameter, about 40 to 50)
nm) and TAF510 (primary average particle diameter, about 40-5)
0 nm) or the like can be conveniently used. When these inorganic fine particles are used as a toner for electrophotography, they may be used alone or in combination of two or more.

The following methods are available as a treatment method for adhering the inorganic fine particles to the silicone oil. Inorganic fine particles that have been thoroughly dehydrated and dried in advance in an oven at several hundreds of degrees Celsius are uniformly contacted with silicone oil, and the silicone oil is attached to the surface of the inorganic fine particles. To attach the inorganic fine particle powder and the silicone oil, use a mixer such as a rotary blade to mix the fine powder as it is, or dissolve the silicone oil with a solvent having a relatively low boiling point that can dilute the silicone oil. It can be prepared by a method of impregnating the solution with a liquid and removing the solvent and drying. When the viscosity of the silicone oil is high, it is preferable to treat it in a liquid. After that, 10 pieces of inorganic powder with silicone oil attached
By performing heat treatment in an oven at 0 ° C to several hundred ° C,
The hydroxyl group on the surface of the inorganic powder can be used to form a siloxane bond between the metal and the silicone oil, or the silicone oil itself can be further polymerized and crosslinked. The reaction may be promoted by adding a catalyst such as an acid, an alkali, a metal salt, zinc octylate, tin octylate or dibutyltin dilaurate to the silicone oil in advance. Further, the inorganic fine particles may be previously treated with a hydrophobizing agent such as a silane coupling agent before the silicone oil treatment. Inorganic powder that has been hydrophobized in advance has a larger amount of silicone oil adsorbed. Although the amount of free silicone oil is almost determined by this heat treatment, the free silicone oil in the present invention does not necessarily have to be chemically bonded to the surface of the inorganic fine particles, and is physically adsorbed to the pores of the surface of the fine particles. Some of them are included. More specifically, it is a component that is easily detached from the inorganic fine particles upon contact, and the liberation rate is defined by the measurement method described below.

The silicone oil release rate is measured by
It can be measured by the following quantitative method. 1. The extracted sample of free silicone oil is immersed in chloroform, stirred and left to stand. Chloroform is added to the solid content after removing the supernatant liquid, chloroform is newly added, stirred and left to stand. Repeat this operation,
Remove free silicone oil. 2. Quantitative determination of carbon content The quantitative determination of carbon content was measured by a CHN elemental analyzer (CHN coder MT-5 type (manufactured by Yanaco)). 3. Measurement of Silicone Oil Release Rate The silicone oil release rate was determined by the following formula. Silicone oil release rate = (C ₀ −C ₁ ) / C ₀ × 10
0 (%) C ₀ : carbon amount in sample before extraction operation, C ₁ : carbon amount in sample after extraction operation

In the present invention, one or more kinds of known inorganic fine particles which are not surface-treated and / or known inorganic fine particles which are surface-treated with a hydrophobizing agent other than silicone oil are used together with the fluidizing agent of the present invention. You may use together. As the hydrophobic treatment agent, for example, a silane coupling agent, a silylating agent, a silane coupling agent having a fluorinated alkyl group, an organic titanate-based coupling agent, an aluminum-based coupling agent and the like can be mentioned as preferable surface treatment agents. The inorganic fine particles to be used in combination have a smaller average particle size than the inorganic fine particles treated with silicone oil. The small inorganic fine particles increase the coverage of the toner surface, and can impart appropriate fluidity to the developer, so that faithful reproducibility with respect to a latent image at the time of development and development amount can be secured. Further, it is possible to prevent aggregation and solidification of the toner during storage of the developer.

The fluidity-imparting agent used in the present invention is preferably used in an amount of 0.1 to 2% by weight based on the toner.
If it is less than 0.1% by weight, the effect of improving toner aggregation will be poor, and if it exceeds 2% by weight, problems such as toner scattering between fine lines, contamination inside the machine, and scratches and abrasion of the photoreceptor tend to occur. is there. A feature of the present invention is that a predetermined fluidity can be secured even with a small amount of addition, and a high resolution image quality can be maintained even in copying and printing a large number of sheets for a long period of time. This effect is obtained with a toner amount of 5 μm or less. It was apparently more effective than the case where the fluidity-imparting agent was added in a large amount by adding a large amount.

Further, the developer of the present invention may further contain other additives within a range that does not have a substantial adverse effect, for example, lubricants such as Teflon (registered trademark) powder, zinc stearate powder and polyvinylidene fluoride powder. Powder; or an abrasive such as cerium oxide powder, silicon carbide powder, strontium titanate powder; or a conductivity-imparting agent such as carbon black powder, zinc oxide powder, tin oxide powder; Also, a small amount of black fine particles can be used as a developability improver.

The magnetic materials used in the magnetic toner of the present invention include iron oxides such as magnetite, hematite and ferrite, metals such as iron, cobalt and nickel, and aluminum, cobalt, copper, lead and magnesium of these metals. Tin, zinc, antimony, beryllium, bismuth,
Cadmium, calcium, manganese, selenium, titanium,
Examples thereof include alloys of metals such as tungsten and vanadium and mixtures thereof. Among these, magnetite is particularly useful. This magnetite is manufactured by a known manufacturing method. For example, an iron sulfate aqueous solution is neutralized with an alkaline aqueous solution to obtain iron hydroxide. After that, the marine ferrous metal suspension whose pH is adjusted to 10 or more is oxidized with a gas containing oxygen to obtain a magnetite slurry. Then, the slurry is washed with water, filtered, dried and crushed to obtain magnetite particles.

These ferromagnetic materials have an average particle size of 0.01 to
The thickness is 1 μm, preferably 0.1 to 0.5 μm.
The amount contained in the magnetic toner is 5 to the toner.
50 wt%, particularly preferably 10 to 40 wt% for toner
% Is good. In addition, the magnetic toner used in the present invention is 5 k
Magnetization in an Oersted magnetic field of 10 to 25 [emu /
g], preferably 15 to 20 [emu / g], and the magnetization in a 1 k Oersted magnetic field is 7 to 20 emu / g, preferably 10 to 17 emu / g. The magnetic substance of the magnetic toner used in the present invention has an FeO content of 5 to 50 w.
t%, preferably 10 to 30 wt% and a specific surface area of 1 to
60 m ² / g, it is preferably preferably 3 to 20 m ² / g. The magnetization was measured by using a REM-1 type magnetization measuring device (manufactured by Toei Industry Co., Ltd.), and the measurement sample was packed in a cell having an inner diameter of 6 mmφ and a height of 2 mm, and an applied magnetic field was gradually added for a maximum of 5,
Change to 000 Oersted. Next, the applied magnetic field is reduced to finally obtain the hysteresis curve of the sample on the recording paper. From this, the saturation magnetization, remanent magnetization, and coercive force are obtained.

As the binder resin for toner of the present invention, conventionally known ones can be widely used. Examples of the binder resin used in the present invention include polystyrene and poly-p.
-Homopolymers of styrene such as chlorostyrene and polyvinyltoluene and substitution products thereof; styrene-P-chlorostyrene copolymers, styrene-propylene copolymers, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene copolymers Coal, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone Styrene-based copolymers such as copolymers, styrene-putadiene copolymers, styrene-isoprene copolymers, styrene-acrylonitrile-indene copolymers; acrylic resins, methacrylic resins, polyvinyl chloride, polyvinyl acetate, polyethylene, Polypropylene , Polyester resin, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin,
Terpene resin, phenol resin, natural resin modified phenol resin, natural resin modified maleic acid resin, polyurethane,
Examples thereof include polyamide resin, furan resin, epoxy resin, coumaroindene resin, silicone resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, and the like, which may be used alone or in combination. In particular, styrene-based copolymers and polyester resins are preferable in terms of development characteristics, fixability and the like.

Comonomers for the styrene monomer of the styrene copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, A monocarboxylic acid having a double bond such as methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide or a substituted product thereof; maleic acid, butyl maleate, malein Dicarboxylic acids having a double bond such as methyl acidate and dimethyl maleate and substituted compounds thereof; vinyl esters such as vinyl chloride, vinyl acetate and vinyl benzoate; ethylene such as ethylene, propylene and butylene System olefins; vinyl methyl ketone, vinyl ketones such as vinyl hexyl ketone;
Examples thereof include vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether, and these vinyl monomers may be used alone or in combination of two or more.

The polyester resin can be produced by a known synthesis method using an alcohol component and an acid component as raw materials.
As the alcohol component, polyethylene glycol, diethylene glycol, triethylene glycol, 1,2
Diols such as propylene glycol, 1,3-propylene glycol, 1,4-propylene glycol, neopentyl glycol, 1,4-butene diol,
Etherified bisphenols such as 1,4-bis (hydroxymethyl) cyclohexane, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, and polyoxypropyleneized bisphenol A, which are saturated or unsaturated with 3 to 22 carbon atoms. Divalent alcohol units substituted with saturated hydrocarbon groups, other divalent alcohol units, sorbitol, 1, 2, 3,
6-hexanetetrol, 1,4-salbitan, pentaesthritol, dipentaesthritol, tripentaesthritol, sucrose, 1,2,4-butanetriol, 1,
Trivalent of 2,5-pentatriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene, etc. At least one selected from the group consisting of the above polyhydric alcohol monomers and the like can be mentioned.

As the acid component, palmitic acid, stearic acid, monocarboxylic acids such as oleic acid, maleic acid,
Fumaric acid, mesaconic acid, citraconic acid, itaconic acid,
Glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, malonic acid, and divalent ones obtained by substituting them with a saturated or unsaturated hydrocarbon group having 3 to 22 carbon atoms. Organic acid monomers, anhydrides of these acids, dimers of lower alkyl ester trinoleic acid, other divalent organic acid monomers, 1,2,4-benzenetricarboxylic acid, 1,2,5
-Benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,
2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8- At least one selected from the group consisting of trivalent or higher polyvalent carboxylic acid monomers such as octane tetracarboxylic acid embol trimer acid and anhydrides of these acids.

In the present invention, a colorant may be contained if necessary. As the colorant, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G,
5G, G), cadmium yellow, yellow iron oxide, ocher, yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), Permanent Yellow (NCG), Vulcan Fast Yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrasan Yellow BGL, Isoindolinone Yellow, Bengala, Lead Tan, Lead Vermilion, Cadmium Red, Kad Muum Mercury Red, Antimon Zhu,
Permanent Red 4R, Para Red, Faise Red, Parachlor Ortho Nitroaniline Red, Resor Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carnmin BS, Permanent Red (F2R, F4R, FRL, FRLL, F4R
H), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resor Rubin G
X, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamin Lake B, Rhodamine Lake. Y, Alizarin Rake,
Thioindigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red, Polyazo Red, Chrome Vermillion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkali Blue Lake, Peacock Blue Lake, Victoria Blue Rake, metal-free phthalocyanine blue, phthalocyanine blue, fast sky blue, indanthrene blue (RS, BC),
Indigo, Ultramarine, Navy Blue, Anthraquinone Blue, Fast Violet B, Methyl Violet Lake, Cobalt Purple, Manganese Purple, Dioxane Violet, Anthraquinone Violet, Chrome Green, Zinc Green, Chromium Oxide, Pyridian, Emerald Green, Pigment Green B, Naphthol Green B , Green gold, acid green lake, malachite green lake, phthalocyanine green, anthraquinone green, titanium oxide, zinc white, lithobon and mixtures thereof can be used. Generally, the amount of binder resin is 10
It is 0.1 to 50 parts by weight with respect to 0 parts by weight.

Further, a release agent may be internally added to the toner of the present invention to prevent offset during fixing. As the release agent, natural wax such as candelilla wax, carnauba wax, rice wax, montan wax, paraffin wax, sazol wax, low molecular weight polyethylene, low molecular weight polypropylene,
There is at least one selected from the group consisting of alkyl phosphates and the like. These are selected depending on the binder resin and the surface material of the fixing roller. The melting point of these release agents is preferably 65 to 90 ° C. If it is lower than this range, blocking during storage of the toner is likely to occur, and if it is higher than this range, offset is likely to occur in a region where the fixing roller temperature is low.

For the toner, it is preferable to use the charge control agent internally added to the toner particles or externally added to the toner particles. The charge control agent makes it possible to control the optimum charge amount according to the developing system. In particular, the present invention is effective when used in the developing method in which the toner concentration is not controlled by using the charge control agent. The polarity control agent used in the toner may be a conventionally known one, and the positive polarity control agent may be a modified product of nigrosine and a fatty acid metal salt; tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetra Quaternary ammonium salts such as butylammonium tetrafluoroborate; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; diorganotin borates such as dibutyltin borate, dioctyltin borate and dicyclohexyltin borate, or two types thereof The above can be used in combination. Among these, polar control agents such as nigrosine compounds and organic quaternary ammonium salts are particularly preferably used.

As the negative polarity controlling agent, for example, organic metal compounds and chelate compounds are effective. Examples thereof include aluminum acetylacetonate, iron (II) acetylacetonate, and chromium 3,5-di-sali-butyl-salicylate. Particularly, acetylacetone metal complex, monoazo metal complex, naphthoic acid or salicylic acid metal complex or A salt is preferable, and a salicylic acid metal complex, a monoazo metal complex or a salicylic acid metal salt is particularly preferable.

The above-mentioned polarity control agent is preferably used in the form of fine particles, and specifically, a number average particle diameter of 3 μm or less is preferable. The amount of the polarity control agent used in the toner is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner manufacturing method including the dispersion method, and is uniquely limited. However, it is preferably used in the range of 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight, based on 100 parts by weight of the binder. If the amount is less than 0.1 parts by weight, the amount of charge of the toner is insufficient, which is not practical. On the other hand, when the amount exceeds 20 parts by weight, the amount of charge of the toner is too large and the electrostatic attraction with the carrier increases, resulting in a decrease in the fluidity of the developer and a decrease in the image density.

As the magnetic carrier used in the present invention, conventionally known ones can be used. For example, magnetic particles such as iron powder, ferrite powder, nickel powder, magnetite powder or the surface of these magnetic particles is treated with a resin. Or magnetic particles dispersed resin particles in which magnetic particles are dispersed in a resin. The average particle size of these magnetic carriers is preferably 35 to 80 μm.

Examples of the resin forming the coat layer include polyethylene, polypropylene, chlorinated polyethylene,
Polyolefin resins such as chlorosulfonated polyethylene; polystyrene, acrylic (for example, polymethylmethacrylate), polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral,
Polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, polyvinylidene, and other polyvinyl and polyvinylidene resins; vinyl chloride-vinyl acetate copolymers, polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoroethylene, etc. Fluorine resin; polyamide; polyester; polyurethane; polycarbonate; amino resin such as urea-formaldehyde resin; at least one selected from the group consisting of epoxy resin and silicone resin. Among these, the one having a silicone resin layer on the surface of magnetic particles or the one having a silicone resin layer containing carbon black has the best spent resistance. As the silicone resin, any conventionally known silicone resin may be used, and examples thereof include straight silicones consisting only of organosiloxane bonds represented by the following formula and silicone resins modified with alkyd, polyester, epoxy, urethane and the like. To be

[Chemical 1]

R1 in the above formula (Formula 1) is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a phenyl group, R2 and R
3 is a hydrogen group, an alkoxy group having 1 to 4 carbon atoms, a phenyl group, a phenoxy group, an alkenyl group having 2 to 4 carbon atoms, an alkenyloxy group having 2 to 4 carbon atoms, a hydroxy group, a carboxyl group, an ethylene oxide group. A glycidyl group or a group represented by the following formula (Formula 2).

[Chemical 2]

R4 and R5 in the above formulas (Formula 1 and Formula 2) are a hydroxy group, a carboxyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and 2 to 4 carbon atoms. Alkenyl group, alkenyloxy group having 2 to 4 carbon atoms, phenyl group, phenoxy group, k, l, m,
n, o, and p are integers of 1 or more. Each of the above substituents is not only an unsubstituted one, but also an amino group, a hydroxy group, a carboxyl group, a mercapto group, an alkyl group, a phenyl group,
It may have a substituent such as an ethylene oxide group, a glycidyl group or a halogen atom.

By including carbon black in the coat layer, desired electric resistance of the carrier can be obtained. As the carbon black used in the present invention, all carbon blacks such as furnace black, acetylene black and channel black can be used. Among these, in particular, by using a mixture of furnace black and acetylene black, it is possible to effectively adjust the conductivity with a small amount of addition and to obtain a carrier having excellent abrasion resistance of the coat layer. These carbon blacks preferably have a particle size of about 0.01 to 10 μm, and are preferably added in an amount of 2 to 30 parts by weight, more preferably 5 to 20 parts by weight, based on 100 parts by weight of the coating resin.

Further, a silane coupling agent, a titanium coupling agent or the like may be added to the carrier coating layer for the purpose of improving the adhesiveness with the core particles and the dispersibility of the conductivity-imparting agent. . The silane coupling agent used in the present invention is a compound represented by the following general formula (over).

[Chemical 3] YRSiX3

However, X is a hydrolyzable group bonded to a silicon atom, and examples thereof include a chloro group, an alkoxy group, an acetoxy group, an alkylamino group and a propenoxy group. Y is an organic functional group that reacts with the organic matrix and includes vinyl group, methacryl group, epoxy group, glycidoxy group, amino group, mercapto group and the like. R is an alkyl group having 1 to 20 carbon atoms or an alkylene group. Among these silane coupling agents, an aminosilane coupling agent having an amino group in Y is preferable in order to obtain a developer having a negative charging property, and an epoxy silane coupling agent in Y is preferable in order to obtain a developer having a positive charging property. Epoxy silane coupling agents are preferred.

The method for forming the coat layer is the same as the conventional method.
The coating layer forming liquid may be applied to the surface of the carrier core particles by a method such as a spraying method or a dipping method. The thickness of the coat layer is 0.
1 to 20 μm is preferable.

As an example of the method for producing the two-component developer according to the present invention, first, the above-mentioned binder resin, release agent, pigment or dye as a colorant, charge control agent, lubricant, and other additives. Etc. after being thoroughly mixed with a mixer such as a Henschel mixer, a batch type two-roll, Banbury mixer or continuous type twin-screw extruder, for example, KTK twin-screw extruder manufactured by Kobe Steel, Toshiba Machine TEM twin-screw extruder, KCK twin-screw extruder, Ikegai Iron Works PCM twin-screw extruder, Kurimoto Iron Works KEX twin-screw extruder, continuous single-screw kneader, such as Buss Knead the constituent materials well using a heat kneader such as a co-kneader, cool,
Coarsely crush with a hammer mill. Further, in the case of color toner, it is common to use a masterbatch obtained by previously melt-kneading a part of the binder resin and the pigment as a colorant for the purpose of improving the dispersion of the pigment. Further, these coarsely pulverized products are finely pulverized using a fine pulverizer using a jet stream or a mechanical pulverizer alone or in combination. Next, the obtained finely divided particles are classified into a predetermined particle size by a classifier using a swirling airflow or a classifier using the Coanda effect. Further, the inorganic fine powder treated with the silicone oil used in the present invention and, if necessary, other fluidity-imparting agents and the like are thoroughly mixed with a mixer such as a Henschel mixer, and the mesh size is 2
Coarse particles and agglomerated particles are removed by passing through a sieve of 5 μm or more. Then, the toner and the carrier obtained by the above method are mixed at a desired ratio in an apparatus such as a V-type mixer, a rocking mixer, a Loedige mixer, a Nauta mixer, a turbula mixer, or a universal mixer, to prepare two components. The developer can be obtained.

Further, in the present invention, a cleaning property improving agent for removing the developer after transfer remaining on the photoconductor or the primary transfer medium is externally or internally added to the developer or the photoconductor. You can also Examples of the cleaning property improver include fatty acid metal salts such as zinc stearate, calcium stearate, and stearic acid, for example, polymer fine particles produced by soap-free emulsion polymerization of polymethylmethacrylate fine particles, polystyrene fine particles, and the like. . The polymer fine particles have a relatively narrow particle size distribution and a volume average particle size of 0.01 to 1 μm.
m is preferable.

[Examples and Comparative Examples] The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Further, in the following examples, parts and% are based on weight unless otherwise specified.

(Production Example of Treatment of External Additive) 300 cs of polydimethylsiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) was dissolved in a predetermined amount of 100 parts by weight of toluene, and 30 parts by weight of the external additive for treatment was stirred therein to make it super Dispersed by sonication.
After visually confirming that there were no aggregates, toluene was distilled off using a rotary evaporator. The obtained solid matter was dried in a vacuum dryer at a set temperature of 50 ° C. until a constant weight was obtained. When heat treatment is performed thereafter, the heat treatment is performed for 2 hours at a predetermined temperature under a nitrogen stream in an electric furnace. The obtained powder was crushed by a jet mill and collected by a bag filter. Table 1 shows various silicone oil-treated external additives thus obtained.

[Table 1]

An example of toner production is shown below. (Toner Preparation Example 1) Polyester resin 100 parts by weight Chromium-containing azo dye 3 parts by weight Magnetite fine particles 23 parts by weight Polypropylene 5 parts by weight After mixing the above mixture with a Henschel mixer, 1
After kneading with a kneading extruder set at 80 ° C,
Allow to cool and solidify, then use a cutter mill for 200-40
Coarse pulverization to 0 μm was performed to obtain a toner pulverized product A.

(Toner Preparation Example 2) Polyester resin 100 parts by weight Chromium-containing azo dye 3 parts by weight Magnetite fine particles 52 parts by weight Polypropylene 5 parts by weight After mixing the mixture of the above formulation with a Henschel mixer, 1
After kneading with a kneading extruder set at 80 ° C,
Allow to cool and solidify, then use a cutter mill for 200-40
The particles were coarsely pulverized to 0 μm to obtain a toner pulverized product b.

(Toner Preparation Example 3) Polyester resin 100 parts by weight Chromium-containing azo dye 3 parts by weight Magnetite fine particles 12 parts by weight Polypropylene 5 parts by weight After mixing the above mixture with a Henschel mixer, 1
After kneading with a kneading extruder set at 80 ° C,
Allow to cool and solidify, then use a cutter mill for 200-40
Coarse pulverization to 0 μm was performed to obtain a toner coarse pulverized product C.

(Toner Preparation Example 4) Polyester resin 100 parts by weight Chromium-containing azo dye 3 parts by weight Magnetite fine particles 58 parts by weight Polypropylene 5 parts by weight After mixing the above mixture with a Henschel mixer, 1
After kneading with a kneading extruder set at 80 ° C,
Allow to cool and solidify, then use a cutter mill for 200-40
The particles were coarsely pulverized to 0 μm to obtain a toner finely pulverized product d.

(Toner Preparation Example 5) Polyester resin 100 parts by weight Chromium-containing azo dye 3 parts by weight Magnetite fine particles 8 parts by weight Polypropylene 5 parts by weight After mixing the above mixture with a Henschel mixer, 1
After kneading with a kneading extruder set at 80 ° C,
It was cooled and solidified, and this was coarsely pulverized by a cutter mill to obtain a toner pulverized product E.

A fine pulverizing device for directly crushing each of the coarsely pulverized products A to E obtained in the above step to a collision plate using a jet stream and a fine pulverized powder obtained by the fine pulverizing device are placed in a classification chamber. An IDS-2 type pulverizing and classifying apparatus (manufactured by Nippon Pneumatic Mfg. Co., Ltd.) having an air classifying apparatus for forming a swirling flow and centrifuging the pulverized material to classify the pulverized material was used for pulverizing and classifying to obtain a classified toner. The desired particle size distribution is measured with a Coulter counter, and the amount of material to be crushed, the pressure and flow rate of high-pressure air for crushing, the shape of the crushing collision member, and the air when air is sucked in the classifier are measured. Can be obtained by changing the inflow position, the inflow direction, the exhaust blower pressure, and the like.

100 parts of this classified toner and an external additive (including the external additive obtained in Production Example of External Additive) were weighed in amounts shown in Table 2, mixed with a Henschel mixer, and sieved with a mesh of 50 μm. Coarse particles were removed to remove coarse particles and agglomerates to obtain electrophotographic toners a to s.
The average particle size of this toner is 5 μm or less, and 1
When the magnetization in a magnetic field of k oersted and 5 k oersted was measured, the values shown in Table 2 were obtained.

[Table 2]

(Production Example of Carrier) Silicone Resin (Organostraight Silicone) 100 parts by weight Toluene 100 parts by weight γ- (2-aminoethyl) aminopropyltrimethoxysilane 5 parts by weight Carbon black 10 parts by weight The above mixture was mixed with a homomixer 20 It was dispersed for a minute to prepare a coating layer forming liquid. The surface of 1000 parts of spherical magnetite having a particle size of 50 μm was coated with this coating layer forming liquid using a fluidized bed type coating device to form a magnetic carrier A.
Got

90 parts by weight of this carrier A and toners a to s
10 parts by weight of each was mixed using a Turbula mixer to obtain two-component developers 1 to 19. Next, this toner a
~ S and developers 1 to 19, the developing device shown in Fig. 1 is incorporated in Ricoh's imagio MF200,
The cleaning property was evaluated.

(Cleanability) After outputting 10,000 sheets, a blank image was output at A3, and the occurrence of abnormal images due to defective cleaning was evaluated. The cleaning conditions will be described later. No cleaning failure occurred: Good Cleaning failure occurred: X The evaluation results are shown in Table 3.

[Table 3]

In Comparative Example 1 containing no silicone oil-treated external additive, Comparative Example 2 having a silicone oil release rate of 78%, and Comparative Example 3 having a silicone oil release rate of 7%,
The cleaning failure occurred even under the cleaning conditions described later, but the cleaning failure did not occur in the other examples.

FIG. 1 is a schematic configuration diagram of a process cartridge of an image forming apparatus adopting an embodiment of the present invention. The developing device 2 disposed on the side of the photosensitive drum 1, which is a latent image carrier, includes a developing housing 3, a developing sleeve 4 as a developer carrier, developer accommodating portions 5a and 5b, and a developer regulating member. It is mainly composed of the first doctor blade 6 and the like.

A developing housing 3 having an opening on the side of the photoconductor drum 1 and a toner hopper 8 as a toner containing portion for containing the toner 7 are formed inside, and adjacent to the toner hopper 8 on the side of the photoconductor drum 1 side. A developer containing portion 5a for containing a developer 9 composed of the toner 7 and a carrier which is a magnetic particle is provided.

Inside the toner hopper 8, there is disposed a toner agitator 11 as a toner supplying means which is rotated by a driving means (not shown). The toner agitator 11 is rotating in the direction of the arrow in order to send the toner 7 in the toner hopper 8 toward the toner supply opening 10 while stirring.

A developing sleeve 4 is arranged in the space between the photosensitive drum 1 and the toner hopper 8. The developing sleeve 4, which is rotationally driven in the direction of the arrow in the drawing by a driving unit (not shown), has a magnet 4a as a magnetic field generating unit, which is disposed inside the developing sleeve 4 such that the relative position of the developing device 2 does not change. .

A first doctor blade 6 is integrally attached to the side of the developer accommodating portion 5a opposite to the side attached to the developing housing 3. The first doctor blade 6 is arranged with a certain gap between the tip of the first doctor blade 6 and the outer peripheral surface of the developing sleeve 4. A second developer regulating member 12 as a regulating member is arranged at a portion of the developer accommodating portion 5a located near the toner supply port 10.

With the above structure, the toner 7 sent out from the inside of the toner hopper 8 by the toner agitator 11 is supplied to the developer 9 carried on the developing sleeve 4 through the toner supply opening 10, and the developer accommodating portion. It is carried to 5a. Then, the developer 9 in the developer accommodating portion 5 a is carried by the developing sleeve 4 and conveyed to a position facing the outer peripheral surface of the photoconductor drum 1, and only the toner 17 is formed on the photoconductor drum 1. A toner image is formed on the photosensitive drum 1 by electrostatically coupling with the latent image.

The developer 9 which is rotated around the developing sleeve 4.
Is braked by the developer staying inside when passing through the developer accommodating portion 5a, so that the conveyance speed is reduced, and as a result, the developer 9 on the developing sleeve 4 near the second developer regulating member 12 is caused. Layer thickness increases. When the toner concentration increases, the frictional force between the developers 9 decreases and the conveying speed decreases, so that the layer thickness is further reduced and the second regulating member 12 is prevented from advancing. When such a state is reached, the opening 14 is prevented from advancing and the staying developer 1 is blocked.
Since the toner is blocked by 3, the toner intake is stopped.
On the contrary, when the toner concentration decreases, the frictional force between the developers increases, and the staying developer 13 is taken into the inside of the developer accommodating portion 5a, so that the rotating developer comes into contact with the toner and the toner is taken in. With the above-described operation, the toner concentration of the developer can be automatically controlled.

Around the photosensitive drum 1, which is a latent image carrier, in addition to the developing device 2, a charging means 36, a cleaning blade 35, a waste toner storage case 31, a waste toner 32,
A waste toner collecting roller 33 for feeding the waste toner cleaned by the cleaning means to the waste toner storage case, and a drum case 34 for holding the photoconductor, the charging means and the cleaning means are arranged. The process cartridge is configured by integrating the drum cases and the developing device described above. The cleaning blade 35 is adhered to the blade supporting member 35a so as to protrude by a predetermined amount, and is attached to the drum case 34 in a counter direction toward the surface of the latent image carrier to clean the surface of the latent image carrier. It is fixed with a screw 35b.

FIG. 2 is a schematic structural view showing the arrangement of the cleaning blade 35 of the cleaning device according to this embodiment. The latent blade moving the tip ridge of the blade 35 to the drum case 34 so as to have a predetermined load. It shows the arrangement in a state where the surface of the image carrier is brought into contact with the surface. The cleaning blade 35 has a flat plate shape and can be made of an elastic material such as polyurethane rubber. The tip ridgeline portion (angle is 90 °) on the surface side of the latent image carrier of the tip portion of the cleaning blade 35 protruding from the tip of the blade supporting member 35a by a predetermined amount is brought into contact with the image carrier to form a tip. Surface, the residual toner on the surface of the photoconductor is blocked and scraped off.

In the present invention, it is difficult to measure the cleaning angle θ1 itself during the cleaning operation, but the Young's modulus E of the cleaning blade 35 and the cleaning blade 3 which are the characteristic values that determine the cleaning angle θ1.
5, the thickness t of 5, the amount of protrusion l of the cleaning blade 35 from the blade supporting member 35a, and the load per unit length in the width direction of the cleaning blade during the cleaning operation were evaluated to obtain good cleaning performance. In case of cleaning blade 35
Young's modulus E, thickness t of the cleaning blade 35, cleaning blade 35 from the blade supporting member 35a
It has been found that the protrusion amount l of the above satisfies a certain relationship.

As an example, the Young's modulus of the cleaning blade (45 to 65 kgf / cm 2) (the cleaning blade hardness is 62 to 75 Hs), the thickness of the cleaning blade (1.3 to 2.2 mm), and the blade supporting member 35.
Amount of protrusion of the cleaning blade 35 from a (6 to
By using polyurethane rubber of 8 mm), the contact pressure for cleaning is (20-40 g / c) as shown in FIG.
m), the cleaning angle θ1 becomes (75 to 85 °),
At this time, by using the above-mentioned toner and developer, cleaning failure due to toner slipping through or chipping of the blade ridge line, squeal or chatter between the blade and the photoconductor, blade curling, and blade scratching performance No abnormal image was generated due to adhesion of toner additives or paper powder to the body surface.

[0088]

As described above, according to the first aspect of the invention, the magnetic toner contains the inorganic fine particles in which the liberation rate of silicone oil is in an appropriate range and the saturation magnetization is in an appropriate range. Therefore, by using the magnetic toner as a developer, it is possible to obtain a high quality image free from toner scattering, transfer omission, and background stain. In particular, when the developing sleeve or the photosensitive member such as a small developing device has a small diameter and only the elastic rubber blade is used for the cleaning system, the above-described effect is great.

According to the second aspect of the present invention, when silica or titanium oxide is used as the inorganic fine particles, the release rate of the silicone oil can be appropriately maintained, and the magnetic toner containing the inorganic fine particles is used as the developer. By using
A higher quality image can be obtained.

According to the invention of claim 3, the particle size distribution of the toner has a weight average particle size of 6.0 to 8.0 μm and 5 μm.
When the toner particles of m or less are 40 to 80% by number, and more preferably 40 to 60%, an image with higher definition and higher resolution can be obtained.

According to the invention of claim 4, since the magnetic toner according to any one of claims 1 to 3 is used as a developer, the toner is sufficiently charged.
It is possible to form a high-quality image free from image stains due to poor cleaning.

According to the fifth to tenth aspects of the invention, in the image forming apparatus using the magnetic toner according to the first to third aspects as a developer, the relationship between the cleaning blade and the latent image carrier is more appropriate. Since it is set, cleaning failure due to toner slipping or blade ridgeline chipping, squeal or chatter between the blade and the photoconductor, blade flipping, toner additive or paper dust on the photoconductor surface due to insufficient scraping performance of the blade The occurrence of an abnormal image due to the adherence of is suppressed.

According to the invention of claim 11, claim 1
Since the magnetic toners described in 1 to 3 are used as a developer and the relationship between the cleaning blade and the latent image carrier is set more appropriately, the surface of the latent image carrier is 120 mm /
It is possible to form a high-quality image even with a linear velocity of sec to 150 mm / sec, and it is possible to provide an image forming apparatus having a medium or higher copying or printing speed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a process cartridge of an image forming apparatus to which the present invention is applied.

FIG. 2 is a schematic configuration diagram showing an arrangement of a cleaning blade of the cleaning device.

FIG. 3 is a graph showing the relationship between the cleaning angle and the contact pressure.

[Explanation of symbols]

1 photoconductor drum 2 Development device 3 Development housing 4 Development sleeve 4a magnet 5a developer container 5b developer container 6 First Doctor Blade 7 toner 8 toner hopper 9 developer 10 Toner supply opening 11 Toner agitator 12 Second developer regulating member 13 Retained developer 14 openings 17 Toner 31 Waste toner storage case 32 Waste toner 33 Waste toner collection roller 34 drum case 35 cleaning blade 35a Blade support member 35b screw 36 charging means

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 21/00 370 G03G 9/10 352 21/10 21/00 318 (72) Inventor Atsuya Daiji Naka, Ota-ku, Tokyo 1-3-6 Magome In Ricoh Co., Ltd. (72) Inventor Junichi Sano 1-3-6 Nakamagome, Ota-ku, Tokyo In-house Co., Ltd. (72) Ricoh Co., Ltd. Hisao Koike 1-3-3 Nakamagome, Ota-ku, Tokyo No. 6 In Ricoh Company (72) Inventor Fumihiro Sasaki 1-3-6 Nakamagome, Ota-ku, Tokyo In-house Ricoh Company (72) Hiroto Higuchi 1-3-6 Nakamagome, Ota-ku, Tokyo Within Ricoh Co., Ltd. (72) Inventor Maiko Kondo 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co. Ltd. (72) Kenzen Sekine 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Masayuki Yamane 1-3-6 Nakamagome, Ota-ku, Tokyo Within Ricoh Co., Ltd. F-term (reference) 2H005 AA02 AA08 BA06 CA12 CB07 CB13 EA02 EA05 2H027 DA17 EE03 2H134 GA01 GB02 HD01 HD04 HD07 HD11 HD19 KD08 KG07 KG08 KH01

Claims (11)

[Claims] 1. A magnetic toner comprising at least a binder resin and a magnetic material, wherein the magnetic toner contains inorganic fine particles treated with silicone oil, and the release rate of the silicone oil is 10.
The magnetic toner has a magnetization of (1) 10 to 25 emu / g in a 5 k Oersted magnetic field, and (2) 7 to 20 emu / g in a 1 k Oersted magnetic field. . 2. The magnetic toner according to claim 1, wherein the inorganic fine particles are made of silica and / or titanium oxide. 3. The magnetic toner according to claim 1 or 2, wherein the particle size distribution of the magnetic toner has a weight average particle size of 6.0 to 1.
Toner particles having a size of 0.0 μm and 5 μm or less are 20 to 8
A magnetic toner comprising 0% by number. 4. A magnetic toner according to any one of claims 1 to 3, either the magnetic toner and a magnetic carrier, or the magnetic toner and a magnetic carrier having a coating layer containing at least a silicone resin as a main component. Image forming apparatus using a different developer. 5. The image forming apparatus according to claim 4, wherein the cleaning blade attached to the blade supporting member fixed to the casing supporting the latent image carrier so as to protrude by a predetermined amount, carries the latent image carrier. 20 g / cm to 40 g / cm in the counter direction toward the surface of the latent image bearing member for cleaning the surface of the latent image bearing member in parallel with the body surface and perpendicular to the moving direction of the surface. An image forming apparatus characterized by being attached by pressure. 6. The image forming apparatus according to claim 5, wherein the cleaning blade has a cleaning angle θ1 of 75.
An image forming apparatus, wherein the image forming apparatus is installed at an angle of about 85 °. 7. The image forming apparatus according to claim 5, wherein the cleaning blade has a hardness of 62 to 75 Hs (JI
An image forming apparatus characterized by being S-A). 8. The image forming apparatus according to claim 5, wherein the material of the cleaning blade is polyurethane rubber. 9. The image forming apparatus according to claim 5, wherein the cleaning blade has a free end length of 6 to 8 mm. 10. The image forming apparatus according to claim 5, wherein the cleaning blade has a thickness of 1.3 mm to 2.2 m.
An image forming apparatus, wherein the image forming apparatus is m. 11. The image forming apparatus according to claim 5, wherein the surface of the latent image carrier is 120 mm / sec to 150 mm /
An image forming apparatus characterized by being moved at a linear velocity of sec.