JPH07199525A - Magnetic developer and image forming method using the same - Google Patents

Abstract

PURPOSE:To provide a magnetic developer high in fidelity to an original, signals, that is, to a latent image and substantially freed of fog and trailing of the developer and high in resolution and precise reproducibility and to provide an image forming method using this developer. CONSTITUTION:The developer is formed by externally adding a fine inorganic powder treated with an organic material to magnetic toner particles containing at least a binder resin, a liquid lubricant, and a magnetic powder, and the magnetic material is composed of a metal oxide having a magnetization strength of 10 to 50emu/g in a magnetic field of 1k0e, the toner particles have the liquid lubricant on the surfaces or near them, and the magnetic developer has a weight average particle diameter of 4.0 to 10mum, and the image forming method of using this developer is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic developer and an image forming method used in electrophotography, electrostatic recording, magnetic recording and the like.

[0002]

2. Description of the Related Art Conventionally, a number of electrophotographic methods are known, but generally, a photoconductive material is used to form an electric latent image on a photoconductor by various means, and then the electrophotographic image is formed. The latent image is developed with a developer to make it a visible image, and if necessary, the developer image is transferred to a transfer material such as paper, and then the developer image is fixed on the transfer material by heat or pressure to make a copy. You get what you get.

In recent years, in addition to conventional copying machines, there have been many printers, facsimile machines, and the like using electrophotographic methods. Particularly in printers and facsimiles, a developing device using a one-component developer is often used because it is necessary to reduce the size of the copying device.

Unlike the two-component developing system, the one-component developing system does not require carrier particles such as glass beads or iron powder, and therefore the developing device itself can be made compact and lightweight. Furthermore,
In the two-component developing method, it is necessary to keep the toner concentration in the developer constant, so that a device for detecting the developer concentration and supplying a required amount of toner is required. Therefore, also in this case, the developing device becomes large and heavy. The one-component developing method does not require such an apparatus, and is preferable because it can be made small and light. Also, as for printer devices, LED and LBP printers have become the mainstream of the market recently, and the direction of technology is higher resolution, that is, conventional 240 or 300 dpi.
That was 400, 600 or 800 dpi. Therefore, the developing system is also required to have higher definition.

Further, the copying machines are also becoming more sophisticated, and for this reason, the digitalization is progressing. In this direction, since the method of forming an electrostatic image by a laser is the main method, it is also advancing toward the direction of high resolution, and here too, a high resolution / high definition developing method is required as in the case of a printer. Japanese Patent Application Laid-Open No. 1-112253 and Japanese Patent Application Laid-Open No.
A developer having a small particle size is proposed in Japanese Patent Publication No.-284158.

In copying machines, there is always a demand for higher speed and stabilization. Especially for medium speed machines or high speed machines, the two-component developing method is the mainstream. This is because in such a large machine, the stability for long-term use at high speed becomes more important than the problem of the size and weight of the developing device. Generally, the toner of the two-component developer is colored with carbon black or the like, and the other components are mostly composed of polymers.

For this reason, the toner particles are light and have no force to adhere to the carrier particles other than the electrostatic force, so that the toner is scattered especially at high-speed development, and the lens, the original glass, the transport section, etc. are used for a long period of time. May stain the image and impair the stability of the image. Therefore, a two-component developer has been put into practical use in which a magnetic substance is contained in the toner to make the developer heavy and at the same time adhere to the magnetic carrier particles not only by electrostatic force but also by magnetic force to prevent toner scattering. .

As described above, the developer containing the magnetic material is becoming more and more important. By the way, in the one-component magnetic development method, since the developer is developed in a chain (generally called “brush”) at the time of development, the resolution in the horizontal direction of the image becomes worse than that in the vertical direction. easy. For example, the trailing phenomenon is likely to occur due to the protrusion of the spikes in the non-image portion in the latter half of the developed image,
Rough images tend to occur more easily than in the two-component developing method.

Therefore, as a method of further improving the image reproducibility, it is conceivable to make the ears of the magnetic developer shorter and denser. As a means to reduce the amount of magnetic material in the developer,
Means for strongly contacting the developer layer thickness regulating agent with the developer carrier has been considered. However, for example, when the amount of the magnetic material is reduced, the charge amount of the developer generally becomes excessive, so-called charge-up phenomenon occurs, and the image quality is lowered such as a decrease in image density and an increase in fog.

The relationship between the magnetic strength of the magnetic developer and the shape of the spikes is also qualitatively understood as follows. That is, when the magnetization intensity of the magnetic developer is large, a strong attractive force along the magnetic field direction and a strong repulsive force in the direction perpendicular to the magnetic field are generated between the magnetic developer particles. Therefore, when the strength of magnetization is high, the ears formed by the magnetic developer become longer,
The density of the spikes on the developer carrier becomes coarse and the individual spikes become thin. On the contrary, if the magnetic strength of the magnetic developer is small, then the ears are short and the ears on the developer carrier are dense, but the bonds between the magnetic developer particles are not broken. The individual panicles become thick and short, and become aggregated.

In this case, the magnetic developer particles present inside the spikes are less likely to come into contact with the surface of the developer carrier, resulting in poor charging. Such developer particles having a poor charging cause fog on the image and deteriorate the image quality. Further, when the developer becomes fine particles (generally 9 μm or less), the charge-up phenomenon of the developer due to the decrease in the amount of the magnetic material is likely to occur, and the charged up developer or the fine powder developer is subjected to the force such as the mirroring force. It adheres strongly to the carrier and causes a decrease in image density.

Further, when the developer layer thickness regulating member is strongly brought into contact with the developer carrier, there are problems such as wear of the developer layer thickness regulating member and an increase in driving load, which is not preferable. Further, in recent years, from the viewpoint of environmental protection, the primary charging and transfer processes using corona discharge, which have been conventionally used, and the primary charging and transfer processes using a photoconductor contact member are becoming mainstream.

For example, the methods described in JP-A-63-149669 and JP-A-2-123385 have been proposed. These are related to the contact charging method and the contact transfer method, but a conductive elastic roller is brought into contact with the electrostatic latent image carrier and the electrostatic latent image carrier is applied while applying a voltage to the conductive roller. Is uniformly charged, and then a developer image is obtained by the exposure and development steps, and then a transfer material is passed through while pressing another conductive roller to which a voltage is applied to the electrostatic latent image carrier. After the developer image on the electrostatic latent image carrier is transferred to a transfer material, a copied image is obtained through a fixing process.

However, in such a roller transfer system that does not use corona discharge, the transfer member is brought into contact with the photoconductor through the transfer member during transfer, so that the developer image formed on the photoconductor is transferred. When the image is transferred to the material, the developer image is brought into pressure contact, which causes a problem of partial transfer failure called so-called transfer void.

Further, in the roller charging system, the physical and chemical action of the surface of the electrostatic latent image carrier due to the discharge generated between the charging roller and the electrostatic latent image carrier is different from that in the corona charging system. In particular, in the combination of organic photoreceptor / blade cleaning, there is a drawback that problems such as fusion of the developer onto the photoreceptor and poor cleaning due to deterioration of the photoreceptor surface are likely to occur (roller). The combination of charging / organic photoreceptor / single component magnetic developing method / roller transfer / blade cleaning makes it easy to reduce the cost and size and weight of the image forming apparatus. This is the main method for machines, printers and facsimiles.)

Therefore, the developer used in such an image forming method is required to have excellent releasability and lubricity. Therefore, Japanese Examined Patent Publication No. 57-13868,
JP-A-54-58245, JP-A-59-1970
48, JP-A-2-3073, JP-A-3-6
A method of incorporating a silicone compound is disclosed in Japanese Patent No. 3660, US Pat. No. 4,517,272 and the like. However, in these methods, since the silicone compound is directly added to the toner, the silicone compound which is not compatible with the binder resin is poorly dispersed in the toner, and the chargeability of the toner particles becomes non-uniform, and There is a problem that developability deteriorates with repeated use.

In recent years, so-called recycled paper has become the mainstream for copy paper from the viewpoint of environmental protection. However, since recycled paper has a large amount of paper powder and filler powder, the problems such as developer fusion and cleaning failure are
This is the direction that is promoted by the use of recycled copy paper. These problems must be solved by all means in order to obtain an image forming apparatus which can obtain a high-resolution / high-definition image with a small size, a light weight, and a low cost while clearing environmental problems.

[0018]

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide a magnetic developer and an image forming method which solve the above problems of the prior art. That is, an object of the present invention is to provide a high-resolution, high-definition reproducible magnetic developer and image forming method that are faithful to the original and to the signal, that is, substantially fog that is faithful to the latent image and developer tailing. To provide. Still another object of the present invention is to provide a magnetic developer and an image forming method which are excellent in transferability and in which voids in transfer do not occur even in a roller transfer system, or these phenomena are suppressed.

Further, another object of the present invention is whether or not the developer is fused and the cleaning is not defective, which is excellent in releasability and slipperiness, and these functions are maintained and maintained for a long time and after printing a large number of sheets. Another object is to provide a magnetic developer and an image forming method in which these phenomena are suppressed. Still another object of the present invention is to provide a magnetic developer and an image forming method in which charging abnormality or image defect due to contamination of a member pressed against an electrostatic latent image carrier does not occur, or these phenomena are suppressed. To do.

[0020]

The above object can be achieved by the present invention described below. That is, the present invention provides a magnetic developer obtained by externally mixing magnetic toner particles containing at least a binder resin, a liquid lubricant and a magnetic substance, and an organically treated inorganic fine powder, wherein the magnetic substance has a magnetic field of 1K. A magnetic substance formed of a metal oxide having a magnetization intensity in Oersted of 10 to 50 emu / g, the toner particles having a liquid lubricant on the surface or in the vicinity of the surface, and the magnetic developer. Has a weight average particle diameter of 4.0 to 10 μm, and an image forming method using the magnetic developer.

[0021]

The operation of the present invention is as follows. In the development area space, the developer particles can be prevented by the appropriate electrostatic cohesive force of the developer particles on the developer carrier and the individual lubricity of the particles, as well as the appropriate magnetic binding force on the developer carrier. The shape of the ears is rather close to that of individual developer particles, and the faithful flight of the developer particles to the electrostatic latent image is achieved. At the transfer site where transfer material / magnetic developer / electrostatic latent image carrier exists, liquid lubricant adheres to the surface of the electrostatic latent image carrier and good release of the developer particles. Depending on the property, the developer particle group can be uniformly transferred from the surface of the electrostatic latent image carrier to the transfer material.

At the cleaning site where the cleaning blade / transfer residual developer / electrostatic latent image carrier exists, the electrostatic cohesive force between the developer particles and the electrostatic latent image carrier electrostatic charge. The adhesive force can be kept low, and the surface of the electrostatic latent image carrier is coated with a liquid lubricant and the cleaning blade surface. As a result, the surface of the electrostatic latent image carrier is developed even with a slight blade contact pressure. The agent, paper dust, etc. are removed, and the fusion of the developer on the surface of the electrostatic latent image carrier damaged by the discharge is prevented, and the cleaning failure of the electrostatic latent image carrier is suppressed.

Since the electrostatic latent image carrier of liquid lubricant and the surface of the cleaning blade are coated, and the electrostatic cohesive force between the magnetic developer particles is low and the lubricity is good, the developer particles are It is easily dispersed into individual particles at the edge part, and the action such as evenly polishing the surface of the photoconductor with a slight blade contact pressure is achieved, and image dirt and scattering when using a fine particle developer, which was a problem in the past, was achieved. , A high-resolution and high-definition image with virtually no background fog and reversal fog can be obtained, and at the same time, cleaning failure and developer fusion are suppressed, and the life of the electrostatic latent image carrier is extended. To be done.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the preferred embodiments. Examples of the magnetic material used in the magnetic developer of the present invention include metal oxides containing elements such as iron, cobalt, nickel, copper, magnesium, manganese, aluminum and silicon. Examples of the method for producing these magnetic bodies include, for example, in the conventionally known production method, a method of reducing σs by using Mn or Zn in place of partially divalent Fe, a method of magnetizing the hematite surface, and a magnetic method Examples thereof include a method of adding a black pigment (for example, TiO) or the like to the body, and a method of controlling the axial ratio of the magnetic material to reduce σs. Σs of the magnetic particles is 10 to 50 emu / g, preferably 20 to 5 under 1 K oersted.
0 emu / g, especially 25 to 40 emu / g is preferable.

These magnetic particles are BE prepared by the nitrogen adsorption method.
A magnetic substance having a T specific surface area of preferably 1 to 20 m ² / g, particularly preferably 2.5 to 12 m ² / g, and further having a Mohs hardness of 5 to 7 is preferable. The amount of magnetic substance in the magnetic developer is
60 to 200 parts by weight, particularly 70 to 150 parts by weight are preferable with respect to 100 parts by weight of the binder resin. If the amount is less than 60 parts by weight, the developer transportability is insufficient, and unevenness in the developer layer on the developer carrier tends to result in image unevenness. Further, the image density decreases due to an increase in developer tribo. Tends to occur. On the other hand, if the amount exceeds 200 parts by weight, the fixing property tends to have a problem. The average particle size of the magnetic material is 0.05
.About.1.0 .mu.m is preferable, and more preferably 0.1 to 0.
6 μm, more preferably 0.1 to 0.4 μm. Further, these magnetic particles are preferably magnetic materials having a Mohs hardness of 5 to 7.

The liquid lubricant used in the present invention is preferably contained in the toner particles by being carried on the carrier particles such as the magnetic material by means such as adsorption, granulation, aggregation, impregnation or encapsulation. As a result, the liquid lubricant can be uniformly and appropriately present on the surface of the toner particles or in the vicinity of the surface,
It is possible to stabilize the releasability and lubricity of the toner particles.

As the liquid lubricant that imparts releasability and lubricity to the developer of the present invention, animal oil, vegetable oil, petroleum-based lubricating oil or synthetic lubricating oil is used, and synthetic lubricating oil is preferably used because of its stability. To be Synthetic lubricating oils include silicones such as dimethyl silicone, methylphenyl silicone, various modified silicones, pentaerythritol esters, polyol esters such as trimethylolpropane ester, polyethylene, polypropylene, polybutene,
Polyolefin such as poly α-olefin, polyglycol such as polyethylene glycol and polypropylene glycol, silicic acid ester such as tetradecyl silicate and tetraoctyl silicate, diester such as di-2-ethylhexyl sebacate and di-2-ethylhexyl adipate, triester Phosphoric acid esters such as cresyl phosphate, propylphenyl phosphate, polychlorotrifluoroethylene, polytetrafluoroethylene, polyvinylidene fluoride, polyfluoroethylene and other fluorocarbon compounds, polyphenyl ether, alkyl naphthenes, alkyl aromatics, etc. Can be mentioned. Among them, silicone and fluorohydrocarbon are preferable from the viewpoint of thermal stability and oxidation stability.

As the silicone, reactive silicone such as amino-modified, epoxy-modified, carboxyl-modified, carbinol-modified, methacryl-modified, mercapto-modified, phenol-modified, different functional group-modified, polyether-modified,
Non-reactive silicones such as methylstyryl-modified, alkyl-modified, fatty acid-modified, alicoxy-modified and fluorine-modified, straight silicones such as dimethyl silicone, methylphenyl silicone and methyl hydrogen silicone are used. In the present invention, since the liquid lubricant on the surface of the magnetic material or the surface of the carrier is partially released and exists on the surface of the toner particles, its effect is exerted, so that the curable silicone is less effective in nature. .

Further, the reactive silicone or the silicone having a polar group has a small amount of liberation depending on the degree such that the adsorption to the liquid lubricant carrier medium becomes strong and the compatibility with the binder resin appears. The effect may be inferior.
Even with non-reactive silicone, depending on the structure of the side chain,
The compatibility with the binder resin may appear and the TE effect may be poor. Therefore, dimethyl silicone, fluorine-modified silicone, fluorohydrocarbon, etc. are preferably used because they have little reactivity, little polarity, no strong adsorption, and no compatibility with the binder resin.

The liquid lubricant used in the present invention preferably has a viscosity at 25 ° C. of 100,000 to 200,000 cSt, more preferably 200 to 100,000 cSt, and particularly 50 to 50.
It is 70,000 cSt. If it is less than 10 cSt, problems with developability and storability tend to occur because the amount of low molecular weight components increases. On the other hand, when it exceeds 200,000 cSt, migration and dispersion in the toner particles become non-uniform, and problems easily occur in developability, transferability, stain resistance, and the like. Viscosity measurement of the liquid lubricant in the present invention is performed by the Viscotester VT500.
(Manufactured by Haake). There are several VT500s
Select one of the viscosity sensors for measurement and put the measurement data in the cell for that sensor for measurement. The viscosity (pas) displayed on the device is converted to cSt.

In the present invention, since the liquid lubricant is used by being carried on the magnetic substance or the lubricant carrier particles, the liquid lubricant dispersibility is superior to that when the liquid lubricant such as silicone is simply added as it is. However, in the present invention, the purpose is not merely to improve the dispersibility of the liquid lubricant, but the liquid lubricant is released from the carrier particles to exert its releasability and lubricity, and at the same time, an appropriate liquid It is necessary to have an adsorption strength for the lubricant and prevent excessive release of the liquid lubricant.

By holding the liquid lubricant on the surface of the carrier particles and allowing it to exist on or near the surface of the toner particles, the amount of the liquid lubricant on the surface of the toner particles can be adjusted appropriately. In the present invention, a wheel-type kneading machine or a ladle machine is used as a specific method for supporting the liquid lubricant on the surface of the magnetic material.

When a wheel type kneading machine or a ladle machine is used, the liquid lubricant intervening between the magnetic particles is pressed against the surface of the magnetic particles by a compression action, and is also spread through the gaps between the particles to spread the surface of the particles. Increase the adhesion with
While extending the liquid lubricant by the shearing action, it is said that the position of the particle group is changed by the shearing force to unravel the aggregates in pieces, and the liquid lubricant present on the particle surface is evenly spread by the action of a spatula, etc. By repeating the three actions, the agglomeration between the magnetic particles is sometimes loosened, and the liquid lubricant is particularly uniformly carried on the surface of each particle in a discrete state, which is particularly preferable. still,
As the wheel type kneader, Simpson mix muller, Marutimaru, Stotts mill, Erich mill, backflow kneader and the like are preferably used.

However, using a mixer such as a Henschel mixer or a ball mill, the liquid lubricant as it is, or diluted with a solvent or the like, is directly mixed with the magnetic particles to be carried or directly sprayed on the magnetic particles. Although it is also known that the carrier particles are supported by these methods, it is difficult to uniformly support a small amount of liquid lubricant on the carrier particles in the case of magnetic particles, or these methods are locally applied. Since liquid lubricant is strongly adsorbed by the application of shearing force and heat, or seizure occurs in the case of silicone etc., the liquid lubricant may not be effectively released from the carrier particles. .

Regarding the amount of the liquid lubricant carried on the magnetic material, the amount of the liquid lubricant to the binder resin is important from the viewpoint of its effect. It is important and preferable that the optimum range is such that the amount of the liquid lubricant is 0.1 to 7 parts by weight with respect to 100 parts by weight of the binder resin, and it is carried by the magnetic substance, and more preferably, It is 0.2 to 5 parts by weight, and particularly preferably 0.3 to 2 parts by weight. As the lubricant carrier particles containing the liquid lubricant used in the present invention, in addition to the magnetic material, particles obtained by granulating or aggregating fine particles of an organic compound or an inorganic compound with a liquid lubricant are used as the lubricant carrier. Used as particles. Examples of the organic compound include resin particles such as styrene resin, acrylic resin, silicone resin, polyester resin, urethane resin, polyamide resin, polyethylene resin and fluororesin.

Further, as the inorganic compound, SiO ₂ , Ge
O ₂ , TiO ₂ , SnO ₂ , Al ₂ O ₃ , B ₂ O ₃ , P ₂
O _{5 and} other oxides, silicates, borates, phosphates, borosilicates, aluminosilicates, aluminoborates, aluminoborosilicates, tungstates, molybdates, tellurates and other metals Examples thereof include oxide salts and composite compounds thereof, silicon carbide, silicon nitride, amorphous carbon and the like. These are used alone or as a mixture. As the inorganic compound fine powder, inorganic compound fine powder manufactured by a dry method and a wet method is used.

The dry method referred to here is a method for producing fine particles of an inorganic compound produced by vapor phase oxidation of a halide. For example, the reaction equation which is the basis of the method utilizing the thermal decomposition oxidation reaction of a halide gas in oxygen hydrogen is as follows. MX _n +1/2 nH ₂ + 1 / 4O ₂ → MO ₂ + n
HCl In this formula, for example, M is a metal or metalloid element, X
Represents a halogen element, and n represents an integer.

Specifically, AlCl ₃ , TiCl ₄ , G
If eCl ₄ , SiCl ₄ , POCl ₃ and BBr ₃ are used, Al ₂ O ₃ , TiO ₂ , GeO ₂ , SiO ₂ and
P ₂ O ₅ and B ₂ O ₃ are obtained. At this time, if a halide is mixed and used, a composite compound is obtained. Elsewhere, heat C
By applying a manufacturing method such as VD or plasma CVD, it is possible to obtain a dry fine powder. Among them, SiO ₂ , A
L ₂ O ₃ and TiO ₂ are preferably used.

On the other hand, as the method for producing the inorganic compound fine powder used in the present invention by the wet method, various conventionally known methods can be applied. For example, decomposition of sodium silicate by an acid as shown by the following formula, Na ₂ O.XSiO ₂ + HCl + H ₂ O → SiO ₂ .n
H ₂ O + NaCl In addition, degradation by ammonia salts or alkali salts of sodium silicate, after yielding an alkaline earth metal silicate from sodium silicate, a method for the acid-decomposable silicate, sodium silicate solution ionic There are a method of making silicic acid by an exchange resin, a method of using natural silicic acid or a silicate, and the like. Other methods include hydrolysis of metal alkoxides.

The general reaction formula is shown below. M (OR) _n O + 1/2 nH ₂ O → MO ₂
+ ROH In this formula, for example, M is a metal or metalloid element, R
Represents an alkyl group, and n represents an integer. At this time, a composite oxide can be obtained by using two or more kinds of metal alkoxides. Among these, inorganic compounds, particularly metal oxides, are preferable because they have an appropriate electric resistance value. In particular, Si, Al and T
The oxide of i and the complex oxide are preferable.

Alternatively, the surface of which may be previously made hydrophobic by a coupling agent or the like may be used. However, some liquid lubricants tend to be overcharged when the surface of the toner particles is covered. When a non-hydrophobicized substance is used as the carrier particles, an appropriate charge leak can be performed, and good developability can be maintained. Therefore, it is also one of the preferable modes to use carrier particles which have not been subjected to the hydrophobic treatment. The particle size of the carrier fine particles is preferably 0.001 to 20 μm, particularly 0.005 to 10 μm.

The specific surface area of the carrier particles by nitrogen adsorption measured by the BET method is 5 to 500 m ² / g, more preferably 10 to 400 m ² / g, further preferably 20 to 3
50m ² / g is good. If it is less than 5 m ² / g, it tends to be difficult in the present invention to hold the liquid lubricant as lubricant carrier particles having a suitable particle diameter. The amount of the liquid lubricant in the lubricant carrier particles is 20 to 90% by weight, preferably 2
7 to 87% by weight, particularly preferably 40 to 80% by weight.

When the amount of the liquid lubricant is less than 20% by weight, the toner particles are not provided with good lubricity and releasability. Therefore, if a large amount of the lubricant carrier particles is added to the toner, the developability is deteriorated. Easy to be unstable. If it exceeds 90% by weight, it is difficult to uniformly obtain lubricant carrier particles containing a liquid lubricant. Conventionally, methods of adsorbing silicone to SiO ₂ , Al ₂ O _3, TiO, etc. have been proposed, but in these methods, the adsorption is too strong and the liquid lubricant does not easily appear on the toner particle surface, so that the toner particles are not sufficiently exposed. Cannot be imparted with excellent lubricity and releasability, and cannot be effective as lubricant carrier particles in the present invention.

In the present invention, the particle size of the lubricant carrier particles is preferably 0.5 μm or more, more preferably 1 μm or more so that the lubricant can be released while retaining the liquid lubricant. It is also preferred that the component is larger than the particle size of the toner particles. Since these lubricant carrier particles contain a large amount of liquid lubricant and are fragile, some of them collapse during the production of the developer and are uniformly dispersed in the toner particles, and at the same time, the liquid lubricant is released to lubricate the toner particles. And mold releasability can be imparted. On the other hand, since the lubricant carrier particles are present in the toner particles in a state where the liquid lubricant holding ability is maintained, the particle size and the like in the toner particles are not limited.

Therefore, the liquid lubricant is not excessively transferred to the surface of the toner particles, and the fluidity and developability of the developer do not deteriorate. On the other hand, even if a part of the liquid lubricant is separated from the surface of the toner particles, it can be replenished from the lubricant carrier particles, so that the releasability and lubricity of the toner particles can be maintained for a long time. These lubricant carrier particles can be granulated by a method in which droplets of a liquid lubricant or a solution diluted with an arbitrary solvent are adsorbed on carrier fine particles in a mixer, and the solvent is volatilized after granulation. Then, it may be crushed if necessary. Alternatively, a method in which a liquid lubricant or a diluent thereof is added to carrier particles using a kneader or the like and kneaded, and the particles can be pulverized and granulated if necessary, and then the solvent is volatilized is used.

The lubricant carrier particles as described above are based on the binder resin 1
The content is preferably 0.01 to 50 parts by weight, more preferably 0.05 to 50 parts by weight, and particularly preferably 0.1 to 20 parts by weight, relative to 00 parts by weight. If the amount is less than 0.01 parts by weight, the lubricating and releasing effects cannot be obtained, and if the amount exceeds 50 parts by weight, problems in charge stability and productivity tend to occur.
The lubricant carrier particles used in the present invention may be obtained by impregnating or encapsulating a liquid lubricant in a porous powder.
Examples of the porous powder used in the present invention include molecular sieves represented by zeolite, clay minerals such as bentonite, aluminum oxide, titanium oxide, zinc oxide and resin gel. The particle size of the porous powder, such as resin gel, whose particles are disintegrated in the kneading step during toner production is not limited.

On the other hand, the particle size of the porous powder which is difficult to disintegrate is preferably 15 μm or less as the primary particle size. 15 μm
When it exceeds, the dispersion in the toner particles tends to be non-uniform. In addition, BE of porous powder before impregnation with liquid lubricant
Specific surface area by nitrogen adsorption measured by T method is 10-50m
It is preferably ² / g. If it is less than 10 m ² / g, it is difficult to retain a large amount of liquid lubricant, and 50 m ² / g
If it exceeds, the pore size is so small that the liquid lubricant cannot be sufficiently impregnated into the pores.

As a method of impregnating the porous powder with the liquid lubricant, the porous powder can be manufactured by decompressing the porous powder and immersing the porous powder in the liquid lubricant. The porous powder impregnated with the liquid lubricant was 100 parts by weight of the binder resin, and
It is preferable to mix in the range of 1 to 20% by weight. 0.1
If it is less than 20% by weight, there is no effect on improving lubricity and releasability, while if it exceeds 20% by weight, problems tend to occur in the charge stability of the developer. In addition to these, the liquid lubricant is dispersed in the capsule-type lubricant carrier particles encapsulating the liquid lubricant or inside,
Encapsulated, swollen or impregnated resin particles and the like are also used.

In the present invention, it is necessary to disperse the liquid lubricant as toner carrier particles in the toner particles. However, since the lubricant carrier particles and the disintegrated product thereof are uniformly dispersed in the toner particles, the liquid lubricant is also used. It can be uniformly dispersed in individual toner particles. Conventionally, in order to uniformly disperse silicone in a toner, it may be adsorbed on various carrier particles and used, and the above method is superior in uniform dispersibility to the method in which silicone or the like is added directly.

However, the purpose of the present invention is not merely to improve the dispersibility, but it is necessary to release the liquid lubricant from the carrier particles to effectively exert its lubricating effect and releasing effect, and at the same time, it is appropriate. It is important to have the retention strength of and prevent the excessive release of the liquid lubricant. Therefore, in the present invention, it is preferable to use lubricant carrier particles, and lubricant carrier particles obtained by supporting a liquid lubricant on various carrier particles are used. The presence of the magnetic substance or other fine particles on or near the surface of the toner particles makes it possible to adjust the amount of the liquid lubricant on the surface of the toner particles appropriately.

Further, the liquid lubricant is released from the lubricant carrier particles and migrates to the surface of the toner particles. However, if the holding force of the carrier particles is strong, the liquid lubricant is less likely to be released, and hence the migration to the surface of the toner particles is prevented. However, good lubricity and releasability of toner particles cannot be obtained. On the contrary, if the holding force of the carrier particles for the liquid lubricant is weak, the liquid lubricant is easily released, and therefore, the transfer to the surface of the toner particles becomes excessive, the chargeability of the developer becomes unstable, and the developing property becomes poor. Cause problems.
Further, the fluidity of the developer is deteriorated, and problems such as uneven image density are likely to occur. Furthermore, if the liquid lubricant is completely released from the carrier particles, the effect of the lubricity and releasability of the developer is lost.

In the present invention, the liquid lubricant holding force of the lubricant carrier particles is moderate, so that the liquid lubricant is moderately released from the carrier particles, and therefore even if the liquid lubricant is separated from the surface of the toner particles. Since the toner particles are replenished, the lubricity and releasability of the toner particles are maintained. Further, since the carrier particles such as magnetic substance and fine particles are present on or near the surface of the toner particles, the liquid lubricant transferred to the surface of the toner particles can be re-adsorbed.
Excessive seepage of the liquid lubricant can be prevented.
Therefore, the presence of the carrier particles on or near the surface of the toner particles is important for keeping an appropriate amount of the liquid lubricant on the surface of the toner particles. That is, the excess liquid lubricant is absorbed, but the consumed liquid lubricant can assist the function of being quickly replenished.

From the above, the developer of the present invention reaches the equilibrium state of its lubricity and releasability after a certain period of time, and the effect is maximized. Therefore, the effect is improved by passing the storage period after the developer is manufactured, but since the liquid lubricant is in equilibrium with the adsorption by the carrier particles, the liquid lubricant does not excessively appear on the surface of the toner particles. On the other hand, 30
It is preferable to give a heat history of up to 45 ° C., because the developer becomes a developer that can exert its maximum effect in a stable state by accelerating the period. Further, the thermal history brings about an equilibrium state, so that a certain effect is maintained and no harmful effect occurs. The heat history is added at any time after the production of the toner particles, and in the case of the pulverization method, after the pulverization.

It is important and preferable to add the magnetic substance or the lubricant carrier particles so that the amount of the liquid lubricant is 0.1 to 7 parts by weight with respect to 100 parts by weight of the binder resin, and more preferably. 0.2-5 parts by weight, especially 0.3-
2 parts by weight is preferred. The weight average particle diameter of the developer of the present invention is preferably 4 to 10 μm in order to obtain good image quality. When the weight average particle diameter is less than 4 μm, the developer is significantly aggregated, and the productivity of the developer (for example, the filling step)
And handling problems occur. If it exceeds 10 μm, the dot latent image or fine line of 100 μm or less is not sufficiently reproduced.

Examples of the binder resin used in the present invention include homopolymers of styrene and its substitution products such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene; styrene-p-chlorostyrene copolymers, styrene-vinyltoluene. Copolymers, styrene-vinyl naphthalene copolymers, styrene-acrylic acid ester copolymers, styrene-methacrylic acid ester copolymers, styrene-α-chloromethyl methacrylate copolymers, styrene-acrylonitrile copolymers, styrene- Styrene such as vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer System Combined; polyvinyl chloride, phenol resin, natural modified phenol resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane resin, polyamide resin, furan resin, epoxy resin, xylene Examples thereof include resins, polyvinyl butyral resins, terpene resins, coumarone indene resins, petroleum-based resins and the like.

A crosslinked styrene resin is also a preferable binder resin. Examples of the comonomer for the styrene monomer of the styrene-based copolymer include acrylic acid,
Methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate,
Monocarboxylic acid having a double bond such as butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, etc. or a substituted product thereof; for example, maleic acid, butyl maleate, methyl maleate, dimethyl maleate, etc. A dicarboxylic acid having a double bond and a substituted product thereof; for example, vinyl chloride,
Vinyl esters such as vinyl acetate and vinyl benzoate, for example, ethylene-based olefins such as ethylene, propylene and butylene; vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone; for example vinyl methyl Ether, vinyl ethyl ether,
Vinyl ethers such as vinyl isobutyl ether;
Vinyl monomers such as the above are used alone or in combination.

As the cross-linking agent, a compound having two or more polymerizable double bonds is mainly used, and examples thereof include aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; for example, ethylene glycol diacrylate. , Ethylene glycol dimethacrylate,
Carboxylic acid esters having two double bonds such as 1,3-butanediol dimethacrylate; divinyl compounds such as divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfone; and compounds having three or more vinyl groups Are used alone or as a mixture.

In the bulk polymerization method, it is possible to obtain a low molecular weight polymer by polymerizing at a high temperature to accelerate the termination reaction rate, but it is difficult to control the reaction. In the solution polymerization method, a low molecular weight polymer can be easily obtained under mild conditions by utilizing the difference in radical chain transfer depending on the solvent, and by adjusting the amount of the initiator and the reaction temperature. It is preferable to obtain a low molecular weight polymer in the resin composition used.

As the solvent used in the solution polymerization, xylene, toluene, cumene, cellosolve acetate, isopropyl alcohol, benzene or the like can be used. In the case of a styrene monomer mixture, xylene, toluene or cumene are preferred. The solvent is appropriately selected depending on the polymer to be polymerized. The reaction temperature varies depending on the solvent used, the initiator and the monomer to be polymerized, but is 70 ° C to 230 ° C.
It is better to perform at ℃. The solution polymerization is preferably carried out with 30 parts by weight to 400 parts by weight of the monomer per 100 parts by weight of the solvent. Furthermore, it is also preferable to mix another polymer in the solution at the end of the polymerization, and several polymers can be mixed well.

As a polymerization method for obtaining a high molecular weight component or a gel component, an emulsion polymerization method or a suspension polymerization method is preferable. Among them, the emulsion polymerization method is a method in which a monomer which is almost insoluble in water is dispersed as small particles in an aqueous phase with an emulsifier and a water-soluble polymerization initiator is used. In this method, the heat of reaction can be easily adjusted, and the termination reaction rate is low because the phase in which the polymerization is performed (oil phase composed of polymer and monomer) and the aqueous phase are different, resulting in a high polymerization rate. A high degree of polymerization can be obtained. Further, the reason is that the polymerization process is relatively simple, and that the polymerization product is fine particles, so that it is easy to mix with a colorant, a charge control agent, and other additives in the production of toner. Therefore, it is advantageous as a method for producing a binder resin for toner as compared with other methods. However, the added polymer is apt to become impure due to the added emulsifier, and suspension polymerization is a simple method because an operation such as salting out is required to take out the polymer.

In the suspension polymerization, 100 parts by weight or less of the monomer (preferably 1 part by weight) is added to 100 parts by weight of the aqueous solvent.
0 to 90 parts by weight) is preferable. As the dispersant that can be used, polyvinyl alcohol, partially saponified polyvinyl alcohol, calcium phosphate, or the like is used, and is an appropriate amount such as the amount of the monomer in the aqueous solvent, but generally 0.05 to 100 parts by weight of the aqueous solvent. Used in 1 part by weight. The polymerization temperature is appropriately 50 to 95 ° C., but it should be appropriately selected depending on the initiator used and the target polymer. Any type of initiator may be used as long as it is insoluble or hardly soluble in water.

The initiator used is t-butylperm.
Oxy-2-ethylhexanoate, cumyl perpivalate, t-butyl per-oxylaurate, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, di-t-butyl per oxide, t
-Butyl cumyl peroxide, dicumyl peroxide, 2,2'-azobisisobutyronitrile, 2,2 '
-Azobis (2-methylbutyronitrile), 2,2'-
Azobis (2,4-dimethylvaleronitrile), 2,
2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 1,1-bis (t-butylperoxy)
3,3,5-Trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, 1,4-bis (t-butylperoxycarbonyl) cyclohexane, 2,2-bis (t-butylperoxy) Octane,
n-butyl-4,4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane, 1,3-bis (t-butylperoxyisopropyl) benzene, 2,5 -Dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5
-Di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane,
Di-t-butyldiperoxyisophthalate, 2,2-
Bis (4,4-di-t-butylperoxycyclohexyl) propane, di-t-butylperoxy-α-methylsuccinate, di-t-butylperoxydimethylglutarate, di-t-butylperoxyhexa Hydroterephthalate, di-t-butylperoxyazelate,
2,5-Dimethyl-2,5-di (t-butylperoxy) hexane, diethylene glycol bis (t-butylperoxycarbonate), di-t-butylperoxytrimethyl adipate, tris (t-butylperoxy) triazine , Vinyltris (t-butylperoxy) silane, etc., and these may be used alone or in combination. The amount used is 100 parts by weight of the monomer,
It is used at a concentration of 0.05 parts by weight or more (preferably 0.1 to 1.5 parts by weight).

The composition of the polyester resin used in the present invention is as follows. As the divalent alcohol component, ethylene glycol, propylene glycol, 1,
3-butanediol, 1,4-butanediol, 2,3
-Butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3hexanediol, hydrogenated bisphenol A,
Also, bisphenol and its derivatives represented by the following formula (A):

[0064]

[Chemical 1] (In the formula, R is an ethylene or propylene group, and x or y
Are each an integer of 0 or more, and the average value of x + y is 0 to
It is 10. ) Further, diols represented by the formula (B);

[0065]

[Chemical 2] (In the formula, R ′ is CH ₂ CH ₂ — or

[Chemical 3] x and y are integers of 0 or more, and the average value of x + y is 0 to 10. ) Is mentioned.

Examples of the divalent acid component include benzenedicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid and phthalic anhydride, or their anhydrides or lower alkyl esters; succinic acid, adipic acid, sebacic acid, azelaic acid. Alkyl dicarboxylic acids or their anhydrides or lower alkyl esters such as; n-dodecenyl succinic acid, n
-Alkenyl succinic acids such as dodecyl succinic acid or alkyl succinic acids, or their anhydrides or lower alkyl esters; unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, itaconic acid or their anhydrides or lower alkyl esters; etc. Dicarboxylic acids and derivatives thereof.

Further, it is preferable to use a trivalent or higher valent alcohol component acting as a crosslinking component and a trivalent or higher valent acid component in combination. Examples of the trihydric or higher polyhydric alcohol component include, for example,
Sorbitol, 1,2,3,6-hexanetetrol,
1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,
4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2
-Methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxybenzene and the like can be mentioned.

Examples of the trivalent or higher polyvalent carboxylic acid component in the present invention include trimellitic acid, pyromellitic acid, 1,2,4-benzenetricarboxylic acid, 1,
2,5-benzenetricarboxylic 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-
Octane tetracarboxylic acid, embol trimer acid, and their anhydrides or lower alkyl esters;

The following equation

[Chemical 4] (Wherein X is an alkylene group having 5 to 30 carbon atoms or an alkenylene group having at least one side chain having 3 or more carbon atoms), etc., and a polycarboxylic acid such as an anhydride or a lower alkyl ester thereof. Examples thereof include carboxylic acids and derivatives thereof.

The alcohol component used in the present invention is 40 to 60 mol%, preferably 45 to 55 mol.
%, 60-40 mol% as an acid component, preferably 5
It is 5 to 45 mol%. Moreover, it is preferable that the trivalent or higher polyvalent component accounts for 5 to 60 mol% of all components.

From the viewpoint of developability, fixability, durability and cleaning property, a styrene-unsaturated carboxylic acid derivative copolymer, a polyester resin and a block copolymer thereof,
A grafted product, more preferably a mixture of a styrene copolymer and a polyester resin is preferred. Further, as the binder resin for the developer provided for pressure fixing, low molecular weight polyethylene, low molecular weight polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, higher fatty acid, polyamide resin, Examples thereof include polyester resins. These are preferably used alone or in combination.

Further, it is also preferable to include the following waxes in the developer from the viewpoint of improving the releasability from the fixing member during fixing and the fixing property. Paraffin wax and its derivatives, microcrystalline wax and its derivatives, Fischer-Tropsch wax and its derivatives, polyolefin wax and its derivatives, carnauba wax and its derivatives, etc., and these derivatives include oxides and block copolymers with vinyl monomers. Includes polymers and graft modified products. In addition, alcohols, fatty acids, acid amides, esters, ketones, hydrogenated castor oil and its derivatives, plant waxes, animal waxes, mineral waxes, petrolactam and the like can be used. In the magnetic developer of the present invention, the charge control agent can be used by being mixed with developer particles (internal addition) or mixed with developer particles (external addition), which is preferable.

The charge control agent makes it possible to control the optimum charge amount according to the developing system, and in particular, in the present invention, the balance between the particle size distribution and the charge amount can be further stabilized. Examples of materials that control the developer to be negatively charged include the following substances. For example, organic metal complexes and chelate compounds are effective, and examples thereof include monoazo metal complexes, acetylacetone metal complexes, aromatic hydroxycarboxylic acids, and aromatic dicarboxylic acid metal complexes. Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives such as bisphenol.

Further, the following substances are exemplified as those which are controlled to be positively charged. Modified products with nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate and onium salts such as phosphonium salts which are analogs thereof And lake pigments thereof, triphenylmethane dyes and lake pigments thereof (as a laking agent, phosphotungstic acid, phosphomolybdic acid, phosphotungstic molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide) Etc.), metal salts of higher fatty acids; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; dibutyltin borate, dioctyltin borate, dicyclohexyltin borate. Of diorgano tin borate such; it may be used in combination singly or two or more kinds.

The above charge control agents are preferably used in the form of fine particles, and in this case, the number average particle diameter of these charge control agents is preferably 4 μm or less, more preferably 3 μm or less. When these charge control agents are internally added to the developer, it is preferably used in an amount of 0.1 to 20 parts by weight, particularly 0.2 to 10 parts by weight, based on 100 parts by weight of the binder resin. Examples of the coloring material that can be further added to the developer of the present invention include conventionally known carbon black and copper phthalocyanine.

Further, the magnetic developer of the present invention has environmental stability,
In order to improve charge stability, developability, fluidity or storability, inorganic fine powder that has been organically treated is stirred and mixed with a mixer such as a Henschel mixer to obtain a magnetic developer characterized by the present invention. To be As the inorganic fine powder used in the present invention, inorganic fine powder such as silicic acid fine powder, titanium oxide, and aluminum oxide is preferable, and silicic acid fine powder is particularly preferable. For example, as the silicic acid fine powder, it is possible to use both the so-called dry method produced by vapor phase oxidation of a silicon halide or the so-called wet silica produced from fumed silica and water glass. However, dry silica having less silanol groups on the surface and inside the silica fine powder and having less production residue such as Na ₂ O and SO ₃ ²⁻ is preferable.

Further, in the case of dry silica, a composite fine powder of silica and another metal oxide is obtained by using another metal halogen compound such as aluminum chloride or titanium chloride together with the silicon halogen compound in the manufacturing process. It is possible and includes them. In the present invention,
It is characterized by using an inorganic fine powder that has been organically treated.
Examples of such an organic treatment method include a method of treating with an organic metal compound such as a silane coupling agent or a titanium coupling agent which reacts with or physically adsorbs the inorganic fine powder, or after treatment with a silane coupling agent, or A method of treating with a silane coupling agent and simultaneously treating with an organic silicon compound such as silicone oil can be mentioned.

Examples of the silane coupling agent used in the organic treatment include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane and allylphenyl. Dichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane,
Chlormethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate, vinyldimethylacetoxysilane, dimethyldiethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyl Disiloxane, 1,3-diphenyltetramethyldisiloxane, and dimethylpolysiloxane having 2 to 12 siloxane units per molecule and each containing a hydroxyl group bonded to a silicon atom at each terminal unit. Etc.

Further, aminopropyltrimethoxysilane having a nitrogen atom, aminopropyltriethoxysilane,
Dimethylaminopropyltrimethoxysilane, diethylaminopropyltrimethoxysilane, dipropylaminopropyltrimethoxysilane, dibutylaminopropyltrimethoxysilane, monobutylaminopropyltrimethoxysilane, dioctylaminopropyldimethoxysilane, dibutylaminopropyldimethoxysilane, dibutylamino Propyl monomethoxysilane, dimethylaminophenyl triethoxysilane, trimethoxysilyl-
γ-propylphenylamine, trimethoxysilyl-γ
A silane coupling agent such as propylbenzylamine may also be used alone or in combination. As a preferable silane coupling agent, hexamethyldisilazane (HMDS)
Is mentioned.

Further, examples of the organic silicon compound include silicone oil. As a preferred silicone oil, one having a viscosity of 0.5 to 10,000, preferably 1 to 1,000 centistokes at 25 ° C. is used, and for example, dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene modified silicone oil. , Chlorophenyl silicone oil, fluorine-modified silicone oil and the like are particularly preferable.

As a method for treating silicone oil, for example, silica fine powder treated with a silane coupling agent and silicone oil may be directly mixed by using a mixer such as a Henschel mixer, or silica as a base may be used. You may use the method of spraying silicone oil on a fine powder. Alternatively, a method may be used in which after dissolving or dispersing silicone oil in a suitable solvent, silica fine powder is added and mixed to remove the solvent.

The organically treated inorganic fine powder used in the present invention has a specific surface area of 3 as measured by the BET method by nitrogen adsorption.
0 m ² / g or more, especially given the 50 to 400 m ² / g good results in the range of, also, it hydrophobized inorganic fine powder used in the present invention with respect to 100 parts by weight of the toner particles 0. It is preferably used in a proportion of 01 to 8 parts by weight, preferably 0.1 to 5 parts by weight, particularly preferably 0.2 to 3 parts by weight.
Parts by weight are. If it is less than 0.01 parts by weight, the effect of improving toner aggregation will be poor, and if it exceeds 8 parts by weight, problems such as toner scattering between fine lines, contamination inside the machine, and scratches and abrasion of the photoconductor tend to occur. is there.

In the magnetic developer of the present invention, other additives may be added within a range that does not have a substantial adverse effect, for example, lubricant powder such as Teflon powder, zinc stearate powder, polyvinylidene fluoride powder or cerium oxide. Powder, silicon carbide powder, abrasive such as strontium titanate powder, or fluidity-imparting agent such as titanium oxide powder and aluminum oxide powder, anti-caking agent, or carbon black powder, zinc oxide powder, oxidation A small amount of a conductivity-imparting agent such as tin powder, and organic fine particles and inorganic fine particles having opposite polarities can be used as a developing property improver.

The absolute value of the charge amount of the developer in the present invention is preferably in the range of 5 to 40 μc / g. When the absolute value of the charge amount of the developer exceeds 40 μc / g, the electrostatic cohesive force of the developer particles and the electrostatic adhesion force to the surface of the electrostatic latent image carrier at the cleaning portion become large, Poor cleaning or fusion of the developer tends to occur.

The method for measuring the charge amount of the developer in the present invention will be described below with reference to FIG. EFV200 / 300 (manufactured by Powder Tech Co., Ltd.) is used as a carrier in an environment of 23 ° C. and relative humidity of 60%, and 0.5% of developer is added to 9.5 g of carrier.
The mixture containing g is placed in a polyethylene bottle having a volume of 50 to 100 ml and shaken by hand 50 times. Then 50 on the bottom
1.0 to 1.2 g of the above mixture is put into a metal measuring container 2 having a 0 mesh screen 3 and a metal lid 4 is placed thereon.

At this time, the weight of the entire measuring container 2 is weighed and W1
g. Next, in the suction device (at least the portion in contact with the measurement container 2 is an insulator), suction is performed from the suction port 7 and the air volume control valve 6 is adjusted to set the pressure of the vacuum gauge 5 to 250 mmAq. In this state, suction is performed for 1 minute to remove the developer by suction. The potential of the electrometer 9 at this time is V (volt). Here, 8 is a capacitor, and the capacitance is C (μF).
Further, the weight of the entire measuring machine after suction is weighed and designated as W (g).
The triboelectric charge amount (μc / g) of this developer is calculated by the following equation. Triboelectric charge amount (μc / g) = CV / W1-W2

A known method is used to prepare the magnetic developer of the present invention. Examples thereof include a binder resin, a wax,
A metal salt or metal complex, a pigment or dye as a colorant, a magnetic substance, and if necessary, a charge control agent and other additives are sufficiently mixed by a mixer such as a Henschel mixer or a ball mill, and then heated rolls or kneaders. Alternatively, while melt-kneading using a heat kneader such as an extruder to mutually dissolve the resins, the metal compound, the pigment, the dye, and the magnetic substance are dispersed or dissolved, and after cooling and solidification, pulverization and classification are performed. The developer of the invention can be obtained.

The weight average particle diameter (D4) of the developer 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) is used as a measuring device, an interface (manufactured by Nikkaki) for outputting number distribution and volume distribution and a PC9801 personal computer (manufactured by NEC) are connected, and an electrolytic solution is 1 A 1% aqueous NaCl solution is prepared using graded sodium chloride.

As the measuring method, the above-mentioned electrolyte aqueous solution 100 was used.
To ˜150 ml, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment for about 1 to 3 minutes by an ultrasonic disperser, and a particle size distribution of particles of 2 to 40 μm based on the number using a 100 μm aperture as an aperture by the Coulter Counter TA-II type. And measure 2
The volume distribution and number distribution of particles of ˜40 μm were calculated, and the weight-based weight average particle diameter (D4: the median value of each channel was used as the representative value of the channels) determined from the volume distribution.

In the present invention, the magnetic property of the magnetic developer is VSM P-1-10 (manufactured by Toei Industry Co., Ltd.)
It was determined from the result of measurement with an external magnetic field of 1 k Oersted at room temperature. The specific surface area was determined according to the BET method by using a specific surface area measuring device Autosorb 1 (manufactured by Yuasa Ionics Co., Ltd.) to adsorb nitrogen gas on the surface of the sample, and calculating the specific surface area using the BET multipoint method.

The developer carrier carrying the magnetic developer of the present invention is preferably covered with a resin layer containing conductive fine particles. The surface roughness of the developer carrier used in the present invention is 0.2 to JIS average center line roughness (Ra).
It is preferably in the range of 3.0 μm. Ra is 0.2
If it is less than μm, the amount of charge on the developer carrying member becomes high and the developability becomes insufficient. When Ra exceeds 3.0 μm, unevenness occurs in the developer coating layer on the developer carrying member, resulting in uneven density on the image.

As the conductive fine particles contained in the resin layer coating the surface of the developer carrier, carbon black, graphite, conductive metal oxides such as conductive zinc oxide, and metal double oxides may be used alone or in combination of two. The above is preferably used. Further, as the resin in which the conductive fine particles are dispersed, a phenol resin, an epoxy resin, a polyamide resin,
Known resins such as polyester resins, polycarbonate resins, polyolefin resins, silicone resins, fluorine resins, styrene resins, and acrylic resins are used. Particularly, a thermosetting or photocurable resin is preferable.
Further, in the magnetic developer of the present invention, the member that regulates the magnetic developer on the developer carrier is regulated by the elastic member that is in contact with the developer carrier through the developer. Is particularly preferable from the viewpoint of uniformly charging the toner.

[0093]

EXAMPLES Next, the present invention will be described in more detail with reference to Production Examples, Examples and Comparative Examples, but this does not limit the present invention in any way. All parts in the following formulations are parts by weight. In FIG. 1, reference numeral 100 denotes a photosensitive drum around which a primary charging roller 117 and a developing device 14 are provided.
0, a transfer charging roller 114, a cleaner 116, a register roller 124 and the like are provided. Then, the photosensitive drum 100 is moved to -700 by the primary charging roller 117.
Charged to V (applied voltage is AC voltage -2.0 kVp
p, DC voltage -700 Vdc).

Then, the laser beam 123 is applied to the photosensitive drum 100 by the laser generator 121 to expose it. The electrostatic latent image on the photosensitive drum 100 is developed with a one-component magnetic developer by the developing device 140 and transferred onto a transfer material by the transfer roller 114. The transfer material carrying the developer image is fixed on the fixing device 12 by the conveyor belt 125 or the like.
6 and is fixed on the transfer material. Further, the developer partially left on the electrostatic latent image carrier is cleaned by the cleaning means 116.

As shown in FIG. 2, the developing device 140 includes a cylindrical developer carrier 102 (hereinafter referred to as a developing sleeve) made of a non-magnetic metal such as aluminum or stainless steel in the vicinity of the photosensitive drum 100. The gap between the photosensitive drum 100 and the developing sleeve 102 is maintained at about 300 μm by a sleeve / drum gap holding member (not shown).

A magnet roller 1 is provided in the developing sleeve.
04 is fixed and arranged concentrically with the developing sleeve 102. However, the developing sleeve 102 is rotatable. The magnet roller 104 is provided with a plurality of magnetic poles as shown in the drawing. S1 is for developing, N1 is for controlling the developer coating amount, S2 is for taking in / conveying the developer, and N2 is for preventing the blowing of the developer. ..

The elastic blade 10 is used as a member for controlling the amount of the magnetic developer attached to the developing sleeve 102 and conveyed.
3, the developing sleeve 10 of the elastic blade 103 is provided.
The amount of developer conveyed to the developing area is controlled by the contact pressure against 2. In the developing area, a DC and AC developing bias is applied between the photosensitive drum 100 and the developing sleeve 102, and the developer on the developing sleeve flies on the photosensitive drum 100 in accordance with the electrostatic latent image to form a visible image. Become.

Production Example of Magnetic Material Bearing Liquid Lubricant Magnetic iron oxide (BET value 5.5 m ^{2 /} g, σs = 38.5)
100 parts of emu / g), a predetermined amount of the liquid lubricant was put into a Simpson Mix Marler (MPVU-2, manufactured by Matsumoto Foundry Co., Ltd.), and after operating for 30 minutes at room temperature, it was further loosened by a hammer mill. In addition, a magnetic material a carrying a liquid lubricant was obtained. Similarly, various liquid lubricants were carried on various magnetic materials. Table 1 below shows the physical property values of the magnetic materials a to h carrying the obtained liquid lubricant. Also, the magnetic substance a
The untreated product was treated as an untreated magnetic substance i, and the untreated magnetic substance h was treated as an untreated magnetic substance j.

Production Example of Liquid Lubricant-Supported Lubricating Fine Particles While the carrier fine particles carrying a liquid lubricant are stirred in a Henschel mixer, a liquid lubricant diluted with n-hexane is added dropwise. After completion of the dropping, the pressure was reduced with stirring to remove n-hexane, and then the mixture was crushed with a hammer mill to obtain lubricating fine particles a to h carrying a liquid lubricant. The physical property values of the obtained lubricant carrier particles a to h carrying the liquid lubricant are shown in Table 2 below. Further, the untreated silica used for the production of the lubricant carrier particles a was designated as the particle i.

Developer Production Example 1 100 parts of magnetic material a Styrene-n-butyl acrylate copolymer (copolymerization ratio 8: 2 Mw = 260,000) 100 parts Iron complex of monoazo dye (negative charge control agent) 2 parts Low molecular weight polyolefin (release agent) 2 parts The above materials are mixed in a blender, melt-kneaded in a twin-screw extruder heated to 140 ° C., and the cooled kneaded material is coarsely crushed with a hammer mill, and the coarsely crushed material is jet milled. The finely pulverized product obtained was finely pulverized with, and the obtained finely pulverized product was classified with an air classifier to obtain a black fine powder. 1.2% by weight based on the obtained black fine powder
Hydrophobic silica fine powder of (hexamethyldisilazane treatment,
BET specific surface area of 200 m ² / g) was added, stirred and mixed with a Henschel mixer, and coarse particles were removed with a 150 mesh sieve to obtain a magnetic developer A. The obtained magnetic developer A had a weight average particle diameter of 6.5 μm.

Developer Example 2 Magnetic substance b 150 parts Styrene-2 ethylhexyl acrylate-n-butyl maleate half ester copolymer (copolymerization ratio 7: 2: 1, Mw = 220,000) 100 parts Negative charge control agent (monoazo dye System chromium complex) 0.8 part Ethylene-propylene copolymer (Mw = 6000) 4 parts Black fine powder was obtained in the same manner as in Production Example 1. A magnetic developer B was obtained in the same manner as in Production Example 1 by adding 1.8% by weight of hydrophobic silica fine powder (the same as in Production Example 1) to 100 parts of this black fine powder. The physical properties of the obtained developer B are shown in Table 3 below.

Developer Production Example 3 Developer Production Example 1 except that the magnetic substance c was 70 parts by weight as the magnetic substance and the amount of hydrophobic silica added was 0.6% by weight.
A magnetic developer C was obtained in the same manner as in. The physical properties of the resulting developer C are shown in Table 3 below.

Developer Production Example 4 Magnetic substance d 120 parts Polyester resin 100 parts Iron complex of monoazo dye (negative charge control agent) 2 parts Low molecular weight polyolefin (release agent) 2 parts 1.2% by weight of silica was 0.9% by weight of hydrophobic titanium oxide fine powder (dimethylsilane-treated BET specific surface area 50 m ² / g), and a magnetic developer was prepared in the same manner as in Developer Production Example 1 except that the above materials were used. I got D. The physical properties of the obtained magnetic developer D are shown in Table 3 below.

Developer Production Example 5 As a magnetic material, 140 parts of magnetic material e was used, and hydrophobic silica fine powder (hexamethyldisilazane treated BET specific surface area 38
Magnetic developer E was obtained in the same manner as in Developer Production Example 1 except that 1.5% by weight of 0 m ² / g) was added. The physical properties of the resulting magnetic developer E are shown in Table 3 below.

Developer Production Example 6 A magnetic developer F was obtained in the same manner as in Developer Production Example 5 except that the magnetic substance f was 120 parts as a magnetic substance and the amount of hydrophobic silica added was 1.4% by weight. It was Obtained magnetic developer F
The physical properties of are shown in Table 3 below. Developer Production Example 7 As a magnetic material, the weight of the magnetic material was 100 parts, and the amount of hydrophobic silica added was 1.
A magnetic developer G was obtained in the same manner as in Developer Production Example 1 except that the content was 0% by weight. The physical properties of the obtained magnetic developer G are shown in Table 2 below.

Comparative Developer Production Example 1 A magnetic developer H was obtained in the same manner as in Developer Production Example 1 except that 100 parts of the magnetic substance h was used as the magnetic substance. The physical properties of the resulting magnetic developer H are shown in Table 2 below. Comparative Developer Production Example 2 A magnetic developer I was obtained in the same manner as in Developer Production Example 1 except that 100 parts of untreated magnetic material i was used as the magnetic material. The physical properties of the resulting magnetic developer I are shown in Table 2 below.

Developer Production Example 8 100 parts of magnetic material a Styrene-n-butyl acrylate copolymer (copolymerization ratio 8: 2 Mw = 260,000) 100 parts Lubricant carrier particles a 1 part Iron complex of monoazo dye (negative Charge control agent) 2 parts Low molecular weight polyolefin (release agent) 2 parts A black fine powder was obtained in the same manner as in Production Example 1. A magnetic developer J was obtained in the same manner as in Production Example 1 by adding 1.2% by weight of hydrophobic silica fine powder (the same as in Production Example 1) to 100 parts of this black fine powder. The physical properties of Developer J thus obtained are shown in Table 3 below.

Developer Production Example 9 Magnetic substance i 100 parts Styrene-n-butyl acrylate copolymer (copolymerization ratio 8: 2 Mw = 260,000) 100 parts Lubricant carrier particles b 4 parts Iron complex of monoazo dye (negative Charge control agent) 2 parts Low molecular weight polyolefin (release agent) 2 parts

Using the same components as in Production Example 1, a black fine powder was obtained. To 100 parts of this black fine powder, 1.2% by weight of hydrophobic silica fine powder (the same as in Production Example 1) was added, and in the same manner as in Production Example 1, a magnetic developer K was obtained. The physical properties of the resulting developer K are shown in Table 3 below. Developer Production Example 10
To 16 lubricant carrier particles b instead of lubricant carrier particles a, respectively
To g, and developer L to R were obtained in the same manner as in Developer Production Example 8 except that the developer particle size and the addition amount of the organically treated inorganic fine powder were changed. Physical properties of the obtained developers L to R are shown in Table 3 below.

Developer Comparative Production Example 3 A developer S was obtained in the same manner as in Developer Production Example 8 except that the untreated particles i were used in place of the lubricant carrier particles a. The physical properties of the resulting developer S are shown in Table 3 below. Developer Comparative Production Example 4 A magnetic developer T was obtained in the same manner as in Developer Production Example 1 except that 100 parts of untreated magnetic material j was used as the magnetic material instead of magnetic material a. Physical properties of the resulting developer T are shown in Table 3 below.

Example 1 An image forming apparatus shown in FIG. 1 was used as the image forming apparatus. An OPC drum having a diameter of 30 mm is used as the electrostatic latent image carrier, and the dark potential Vd = -700 V and the light potential VL = -2.
It was set to 10V. The gap between the photosensitive drum and the developing sleeve is 3
A developing sleeve in which a resin layer having a layer thickness of about 7 μm and a JIS center line average roughness (Ra) of 2.2 μm having the following constitution as a developer carrying member is formed on an aluminum cylinder having a diameter of 16φ and a mirror surface. Using the developing magnetic pole 950
As a gauss and a developer regulating member, a urethane rubber blade having a thickness of 1.0 mm and a free length of 10 mm was brought into contact with the linear pressure of 15 g / cm.

Phenolic resin 100 parts Graphite (particle size of about 7 μm) 90 parts Carbon black 10 parts

Next, as a developing bias, a DC bias component Vdc = -500V and an AC bias component V to be superimposed.
pp = 1600V and f = 2000Hz were used. A transfer roller (made of ethylene-propylene rubber in which conductive carbon is dispersed, diameter 20 mm, contact pressure 50 g / cm) is set at the same speed as the peripheral speed of the photoconductor (48 mm / sec), and +2 KV is applied as a transfer bias to develop the developer. The magnetic developer A was used as the toner, and an image was printed in an environment of 23 ° C. and 65% RH.

As a result, as shown in Table 4 below, a good image having sufficient image density and high resolution without voids in the transfer was obtained. Further, the resolution of a 1-dot latent image of 80 μm was at a sufficiently good level. Further, no abnormalities such as fusion were observed on the surface of the photoreceptor even after printing 5000 sheets continuously.

Comparative Example 1 Developer T was used as a developer, and image formation was performed under the same apparatus and conditions as in Example 1. As a result, trailing was conspicuous on the image as shown in Table 4 below. Also, 80 μm
The resolution of the 1-dot latent image was also insufficient, and an image lacking sufficient sharpness was obtained. Further, fusion of the developer was recognized on the surface of the photoreceptor after continuous printing of 5000 sheets, and white spots were generated on the printed image.

Comparative Example 2 Using Developer I as a developer, image formation was carried out under the same apparatus and conditions as in Example 1. As a result, it was an image with a noticeable hollow in the line portion. Further, fusion of the developer was recognized on the surface of the photoreceptor after printing 5000 sheets continuously, and white spots were generated on the printed image.

Examples 2 to 7 Developers B to G were used as developers, and image formation was performed under the same apparatus and conditions as in Example 1. The results are shown in Table 4 below. Examples 8 to 16 Developers J to R were used as developers, and images were formed under the same apparatus and conditions as in Example 1. The results are shown in Table 4 below.

Comparative Example 3 Using the developer S as a developer, image formation was performed under the same apparatus and conditions as in Example 1. As a result, it was an image with a noticeable hollow in the line portion. Further, fusion of the developer was recognized on the surface of the photosensitive member after continuous printing of 5,000 sheets, and white spots were generated on the printed image. Comparative Example 4 Developer H was used as a developer, and image formation was performed using the same apparatus and conditions as in Example 1. As a result, the trailing was conspicuous on the image. In addition, an image lacking sufficient sharpness was also obtained in the resolution of a 1-dot latent image of 80 μm.

[0119]

[Table 1]

[0120]

[Table 2]

[0121]

[Table 3]

(Continued from Table 3)

[0123]

[Table 4]

Criteria for evaluation of voids: ◯: Very good Δ: Cavity is seen in some fine lines, but good ×: Fine lines cannot be resolved due to voids Trailing evaluation criteria: ◯: Very good Δ: Good × : 80 μm 1-dot reproducibility evaluation standard with noticeable tailing: ◯: Very good Δ: Good ×: No resolution and practically impossible Fusion evaluation standard: ◯: Very good Δ: Some fusion is recognized but practical Poor: Appears on the image and practically impossible. Image density: Measured with Macbeth densitometer RD914.

[0125]

In a magnetic developer obtained by externally mixing magnetic toner particles containing at least a binder resin, a liquid lubricant and a magnetic substance, and an organically treated inorganic fine powder, the magnetic substance has a magnetic field of 1 K Oersted. The strength of magnetization at
It is a magnetic material formed of a metal oxide of 50 emu / g, has a liquid lubricant on or near the surface of the toner particles, and has a weight average particle diameter of 4.0 to 4.0.
The magnetic developer having an average particle size of 10 μm and the image forming method using the magnetic developer do not cause fusion of the developer to the photoreceptor, cleaning failure, dropout during transfer, and tailing, and a high image density. It has become possible to obtain an image with high resolution and high resolution.

[0126]

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an example of an image forming apparatus used in the present invention.

FIG. 2 is an explanatory diagram of a developing device as an example of an image forming apparatus used in the present invention.

FIG. 3 is an explanatory diagram of a triboelectric charge amount measuring method of the developer of the present invention.

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Claims (11)

[Claims] 1. A magnetic developer obtained by externally mixing magnetic toner particles containing at least a binder resin, a liquid lubricant and a magnetic substance, and an organically treated inorganic fine powder, wherein the magnetic substance has a magnetic field of 1 K Oersted. The strength of magnetization at
The toner is a magnetic material formed of a metal oxide having a content of 50 emu / g, the toner particles have a liquid lubricant on the surface or in the vicinity of the surface, and the weight average particle diameter of the magnetic developer is 4.0. A magnetic developer having a thickness of 10 μm. 2. The magnetic developer according to claim 1, wherein the liquid lubricant is carried on a magnetic body by a stirring action, a compression action, a shearing action, a spatula action or the like. 3. The toner particles according to claim 1, wherein the liquid lubricant is contained in the toner particles in the form of lubricant carrier particles containing 20 to 90% by weight of the liquid lubricant with respect to the total weight of the carrier particles.
The magnetic developer according to 1. 4. The viscosity of the liquid lubricant at 25 ° C. is 10
The magnetic developer according to claim 1, which has a viscosity of 200,000 cSt. 5. A visible image obtained by forming an electrostatic latent image on at least an electrostatic latent image carrier by charging and exposure, and developing the electrostatic latent image with a developer, onto a transfer material. In an image forming method of transferring and thereafter cleaning the surface of the electrostatic latent image carrier with a cleaning member, at least one of the charging step, the developing step, the transfer step and the cleaning step is performed by a member contacting the electrostatic latent image carrier under pressure. A magnetic developer which is in two steps, wherein the developer is an externally added mixture of magnetic toner particles containing at least a binder resin, a liquid lubricant and a magnetic substance, and an organically treated inorganic fine powder, The magnetic material is magnetic field 1
The strength of magnetization in K Oersted is 10 to 50 emu
/ G of a metal oxide formed of a metal oxide, the toner particles have a liquid lubricant on the surface or in the vicinity of the surface, and the weight average particle diameter of the magnetic developer is 4.0 to 4.0. 10
An image forming method, which is a magnetic developer of μm. 6. An electrostatic latent image carrier and a developer carrier are arranged in a developing section with a constant gap, and a magnetic developer is provided on the developer carrier with a thickness smaller than the gap. 6. The image forming method according to claim 5, wherein the latent image on the electrostatic latent image carrier is developed by applying the alternating electric field in the developing unit after transporting to the developing unit. 7. The image forming method according to claim 5, wherein the member for regulating the developer on the developer carrier is in contact with the developer carrier via the developer. 8. The image forming method according to claim 5, wherein the developer carrier is coated with a resin layer containing conductive fine particles. 9. The image forming method according to claim 5, wherein the electrostatic latent image carrier is an organic photoconductor. 10. The image forming method according to claim 5, wherein the transfer member is brought into contact with the electrostatic latent image carrier via the transfer material during transfer. 11. The image forming method according to claim 5, wherein a charging member that charges the electrostatic latent image carrier is in contact with the electrostatic latent image carrier.