JP3067073B2 - Magnetic developer and image forming method using magnetic developer - Google Patents

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, many methods are known as electrophotography. In general, a photoconductive substance is used to form an electric latent image on a photoreceptor by various means. The latent image is developed with a developer to form 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, pressure, etc. and copied. Get things.

In recent years, devices using electrophotography have been increasing in number, such as printers and facsimile machines, in addition to conventional copying machines. Particularly, in a printer or a facsimile, a developing device using a one-component developer is often used because it is necessary to reduce the size of a copying device.

The one-component developing method does not require carrier particles such as glass beads and iron powder as in the two-component developing method, and therefore the developing device itself can be reduced in size and weight. Furthermore,
In the two-component developing method, since it is necessary to keep the toner concentration in the developer constant, a device for detecting the developer concentration and supplying a necessary amount of toner is required. Therefore, the developing device also becomes large and heavy here. In the one-component developing system, such a device is not required, and it is preferable because the device can be made small and light. As for the printing apparatus, LED and LBP printers have become mainstream in the recent market, and the direction of the technology is higher resolution, that is, the conventional 240 or 300 dpi.
Has become 400, 600 or 800 dpi. Accordingly, a higher definition has been required for the developing system.

[0005] Also, the functions of the copier have been advanced, and the digitalization has been proceeding. In this direction, the method of forming an electrostatic charge image with a laser is the main method, so it is also proceeding in the direction of high resolution, and here too, a high-resolution and high-definition development method is required similarly to a printer. And JP-A-1-112253 and JP-A-2
JP-A-284158 and the like propose a developer having a small particle size.

[0006] Further, in copiers, higher speed and more stable direction are always desired. In particular, in a medium-speed machine or a high-speed machine, a two-component developing system is mainly used. This is because such a large-sized machine is more important for stability for long-term use at high speed than for the size and weight of the developing device. Generally, the toner of a two-component developer is colored with carbon black or the like, and the other components are mostly made of a polymer.

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 particularly in high-speed development, and the lens, the original glass, the transport section, etc. In some cases, thereby deteriorating the stability of the image. Therefore, a one-component developer has been put to practical use in which a magnetic substance is contained in the toner, the developer is made heavy, and at the same time, the magnetic carrier particles are attached to the magnetic carrier particles by a magnetic force in addition to the electrostatic force, thereby preventing the toner from scattering. .

As described above, developers containing a magnetic material are becoming increasingly important. By the way, in the one-component magnetic developing method, the developer is developed in a chain form (generally called “spike”) at the time of development, so that the resolution in the horizontal direction of the image is worse than that in the vertical direction. easy. For example, the trailing phenomenon due to the protrusion of ears easily occurs in the non-image part in the latter half of the developed image,
Rough images tend to occur more easily than in the two-component development system.

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 means for reducing the amount of the magnetic substance in the developer,
Means or the like for strongly contact with the developer layer thickness regulating portion to the developer responsible lifting body it has been considered. However, for example, when the amount of the magnetic substance is reduced, the charge amount of the developer generally becomes excessively large, so-called a 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 intensity of magnetization of the magnetic developer and the shape of the ears is 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 intensity of magnetization is large, the spike formed by the magnetic developer becomes longer,
Density of bristles of the developer responsible lifting bodies each ear becomes coarse becomes thinner. Further, when the intensity of magnetization opposite to magnetic developer is small, the density of the bristles of the turn panicle shorter developer responsible lifting body becomes dense, for coupling between magnetic developer particles is not solved The individual ears are thick and short and clumped.

[0011] magnetic developer particles in this case is present inside the ears is a chance of contact with the developer in charge bearing member surface is reduced charging failure. Such poorly charged developer particles become fogged on the image and degrade the image quality. Further, when the developer is fine (typically 9μm or less), the charge-up phenomenon of the developer by the magnetic material loss is likely to occur, the developer developer and fine developer charge-up by the force of such reflection force responsible It adheres firmly to the carrier, causing a reduction in image density.

[0012] In the case of a developer layer thickness regulating member is strongly abutted against the developer responsible lifting body, not preferable because problems such as increase of wear and the driving load of the developer layer thickness regulating member. Further, in recent years, from the viewpoint of environmental protection, the primary charging and transfer process using a photoconductor contact member from the conventionally used primary charging and transfer process using corona discharge is becoming mainstream.

For example, the methods described in JP-A-63-149669 and JP-A-2-123385 have been proposed. These contact charging method is concerned with and contact transfer method, a conductive elastic roller to the electrostatic latent image charge of lifting member contact, latent electrostatic image in charge bearing member while applying a voltage to the conductive roller is uniformly charged and then after obtaining a developer image by the exposure and development processes, and passed through a transfer material therebetween while pressing the another conductive roller applying a voltage to the electrostatic latent image charge of lifting body , after transferring to the transfer material a developer image on the electrostatic latent image charge of lifting bodies, to obtain the copied image through the fixing step.

However, in such a roller transfer method that does not use corona discharge, the transfer member is brought into contact with the photosensitive member via the transfer member at the time of transfer, so that the developer image formed on the photosensitive member is transferred. When the developer image is transferred onto the material, the developer image is pressed against the material, which causes a problem of partial transfer failure called so-called “missing transfer”.

Furthermore, a roller charging method, physical and chemical action of the electrostatic latent image in charge bearing member surface by discharge generated between the charging roller and the electrostatic latent image charge of lifting body relative to the corona charging method In particular, in combination with organic photoreceptor / blade cleaning, there is a drawback that problems such as fusion of a developer on the photoreceptor and poor cleaning due to deterioration of the photoreceptor surface easily occur (roller The combination of charging / organic photoreceptor / one-component magnetic developing method / roller transfer / blade cleaning facilitates low cost and small size and light weight of the image forming apparatus. It is the mainstream system for machines, printers, and facsimile machines.)

Therefore, the developer used in such an image forming method is required to be excellent in releasability and lubricity. For that reason, Japanese Patent Publication No. 57-13868,
JP-A-54-58245, JP-A-59- 1970
No. 48, JP-A-2-3073, JP-A-3-6
No. 3,660, U.S. Pat. No. 4,517,272 discloses a method of incorporating a silicone compound. 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. There is a problem that the developing property is deteriorated by 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 generates a large amount of paper powder and filler powder, problems such as developer fusion and poor cleaning are as follows.
This is the direction that is encouraged by the use of recycled copy paper. These problems have to be improved by all means in order to obtain an image forming apparatus capable of obtaining a high-resolution and high-definition image at a small size, light weight, and low cost while clearing environmental problems.

[0018]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a magnetic developer and an image forming method which solve the above-mentioned problems of the prior art. That is, an object of the present invention is to provide a magnetic developer which is faithful to a document and faithful to a signal, that is, substantially fog faithful to a latent image, has high resolution and high definition reproducibility without developer tailing, and an image forming method. 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, do not cause omission during transfer even in a roller transfer method, or suppress these phenomena.

Still another object of the present invention is to provide a toner having excellent releasability and slipperiness and maintaining these functions for a long period of 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, either the charging abnormality and image defects due to contamination of a member pressed against the electrostatic latent image charge of lifting body does not occur, or provide a repressed magnetic developer and an image forming method of these symptoms Is to do.

[0020]

The above objects are achieved by the present invention described below. That is, the present invention relates to 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%. A magnetic material formed of a metal oxide having a magnetization strength of 25 to 40 emu / g in k Oersted, and the liquid lubricant is a binder resin 1
0.1 to 7 parts by weight with respect to 00 parts by weight,
It said toner particles has the liquid lubricant in the vicinity of its surface or surfaces, and the weight average particle diameter of the magnetic developer is 4.0
A magnetic developer having a thickness of 10 to 10 μm; and an image forming method using the magnetic developer.

[0021]

The operation of the present invention is as follows.
Suitable electrostatic cohesion and individual particles of lubricity of the developer particles on the developer responsible lifting body, further in the developing area space by an appropriate magnetic binding force to the developer responsible lifting member in addition, the developer particles From the state of the ears, the shape becomes closer to individual developer particles, and the developer particles can fly faithfully to the electrostatic latent image. In the transfer portion 3's transfer material / magnetic developer / electrostatic latent image charge of bearing member are present, adhere to the electrostatic latent image in charge bearing member surface of the liquid lubricant, as well as good release with the developer particles sex, the developer particles can be uniformly shifted to the transfer material from the electrostatic latent image in charge bearing member surface.

[0022] Electrostatic to the cleaning blade / transfer residual developer / in the cleaning site where three parties are present in the electrostatic latent image in charge bearing member, the developer electrostatic cohesion between particles and the electrostatic latent image charge of lifting body adherence can be kept low, further coating to the electrostatic latent image charge of lifting member and the cleaning blade surfaces of the liquid lubricant, developed from an electrostatic latent image in charge bearing member surface at the results from the minor blade contact pressure agent and paper dust are removed, the developer anti-fusion bonding to the damaged electrostatic latent image in charge bearing member surface, and the cleaning of the electrostatic latent image in charge bearing member failure is suppressed by the discharge.

The coating of the electrostatic latent image charge of lifting member and the cleaning blade surfaces of the liquid lubricant, for even more satisfactory and lubricity electrostatic cohesive force is low between the magnetic developer particles, the developer particles of the cleaning blade It is easy to be dispersed into individual particles at the edge part, and the effect of uniformly polishing the photoreceptor surface with a lighter blade contact pressure is achieved, and image stains and scattering when using fine particle developer, which was a conventional problem , fog, at the same time high resolution and high definition of images that are substantially prevent reversal fog is obtained, it is suppressed cleaning failure and developer fusing, the life of the electrostatic latent image charge of lifting bodies achieved Is done.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to 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. As a method for producing these magnetic materials, for example, a method for reducing σs by using Mn or Zn instead of partially divalent Fe, a method for magnetizing the hematite surface, Examples include a method of adding a black pigment (for example, TiO) to the body, a method of controlling the axial ratio of the magnetic body to lower σs, and the like. Σs of the magnetic particles is 2 5~40emu / g under 1k oersted.

These magnetic particles are obtained by BE adsorption using a nitrogen adsorption method.
A magnetic material having a T specific surface area of preferably 1 to 20 m ² / g, particularly preferably 2.5 to 12 m ² / g, and a Mohs hardness of 5 to 7 is preferred. The amount of magnetic material in the magnetic developer is
It is preferably from 60 to 200 parts by weight, particularly preferably from 70 to 150 parts by weight, based on 100 parts by weight of the binder resin. If the amount is less than 60 parts by weight, the transportability of the developer is insufficient, and the developer layer on the developer carrier tends to be uneven, which tends to cause image unevenness. Tends to occur. On the other hand, if it exceeds 200 parts by weight, a problem tends to occur in the fixing property. The average particle size of the magnetic material is 0.05
To 1.0 μm, more preferably 0.1 to 0.1 μm.
6 μm, more preferably 0.1 to 0.4 μm. Further, these magnetic particles are preferably magnetic substances having a Mohs hardness of 5 to 7.

The liquid lubricant used in the present invention, adsorbed to the magnetic or responsible particles, granulation, agglomeration, is responsible lifting by means such as impregnation or inclusion, it is preferably contained in the toner particles. As a result, a uniform and appropriate amount of liquid lubricant can be present on or near the toner particle surface,
The releasability and lubricity of the toner particles can be stabilized.

As the liquid lubricant for imparting the releasing property 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 in view of its stability. Can be Synthetic lubricating oils include silicones such as dimethyl silicone, methyl phenyl silicone and various modified silicones, polyol esters such as pentaerythritol ester and trimethylol propane ester, polyethylene, polypropylene, polybutene,
Polyolefins such as poly-α-olefins, polyglycols such as polyethylene glycol and polypropylene glycol, silicates such as tetradecyl silicate and tetraoctyl silicate, diesters such as di-2-ethylhexyl sebacate and di-2-ethylhexyl adipate, and triesters Phosphoric acid esters such as cresyl phosphate and propyl phenyl phosphate, fluorinated hydrocarbon compounds such as polychlorotrifluoroethylene, polytetrafluoroethylene, polyvinylidene fluoride, and polyfluoroethylene; polyphenyl ethers, alkyl naphthenes, and alkyl aromatics. No. Among them, silicone and fluorinated hydrocarbon are preferred in terms of heat stability and oxidation stability.

Examples of silicone include reactive silicone such as amino-modified, epoxy-modified, carboxyl-modified, carbinol-modified, methacryl-modified, mercapto-modified, phenol-modified, and heterofunctional group-modified, and polyether-modified.
Non-reactive silicones such as methylstyryl modification, alkyl modification, fatty acid modification, alicoxy modification, and fluorine modification, and straight silicones such as dimethyl silicone, methylphenyl silicone, and methyl hydrogen silicone are used. In the present invention, since the liquid lubricant of the magnetic surface or collateral bearing member surface to exert its effect by the presence of the part free to toner particle surfaces, curable silicones is lessened its nature effect.

[0029] Further, the silicone having a reactive silicone or polar group, or adsorption becomes stronger in the liquid lubricant in charge carrying media, such as compatibility appears for the binder resin, the free volume is reduced depending on its degree, The effect may be poor.
Also, even with non-reactive silicone, depending on the structure of the side chain,
In some cases, compatibility with the binder resin appears and the effect is inferior. Therefore, dimethyl silicone, fluorine-modified silicone, fluorocarbon, and the like are preferably used because they have low reactivity and polarity, do not have strong adsorption, and have 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, particularly preferably 50 to 200,000 cSt.
70,000 cSt. If it is less than 10 cSt, problems in developability and storage stability are likely to occur due to an increase in low molecular weight components. On the other hand, if it exceeds 200,000 cSt, migration and dispersion in the toner particles become non-uniform, and problems such as developability, transferability, and stain resistance are likely to occur. The measurement of the viscosity of the liquid lubricant in the present invention is performed using a Visco Tester VT500.
(Manufactured by Haake). Some VT500
Arbitrarily select one of the viscosity sensors for measurement, put the measurement data in the cell for the sensor, and measure. The viscosity (pAs) displayed on the device is converted to cSt.

[0031] In the present invention, since the liquid lubricant is used in allowed responsible lifting the magnetic or lubricant carrier particles, simply excellent liquid lubricant dispersion than added as a liquid lubricant such as silicone. However, in the present invention and not for purposes simply improve the liquid lubricant dispersion, and at the same time and to liberate the liquid lubricant from the responsible particles, to exhibit its releasability and lubricity, suitable liquid It is necessary to provide the lubricant with a sufficient adsorption strength to prevent the liquid lubricant from being excessively released.

The amount of the liquid lubricant on the surface of the toner particles can be appropriately adjusted by holding the liquid lubricant on the surface of the carrier particles and causing the liquid lubricant to be present on or near the surface of the toner particles. In the present invention, the liquid lubricant is applied to the surface of the magnetic material.
As a specific method for responsible lifting wheel type kneading machine or kneader is used.

When a wheel-type kneader or mill is used, the liquid lubricant interposed between the magnetic particles is pressed against the surface of the magnetic particles by a compressing action, and is spread through the gaps between the particles. Increase the adhesion with
While extending the liquid lubricant by the shearing action, the position of the particles is changed by the shearing force to disperse the cohesion, and the liquid lubricant existing on the particle surface is evenly spread by the action of the spatula. by three actions are repeated with untangled the aggregation of the magnetic particles, especially preferred because it is responsible lifting liquid lubricant uniformly to individual particle surfaces with particles one by one loose state. still,
As the wheel-type kneader, a Simpson mix muller, a multi-mul, a Stott's mill, an Erich-mill and a backflow kneader are preferably used.

[0034] However, as a liquid lubricant with such mixer Henschel mixer or a ball mill, or or is diluted to collateral lifting directly mixed with magnetic particles in a solvent such as, directly sprayed on magnetic particles it is also known how or to responsible lifting Te, but these methods in the case of magnetic particles, or it is difficult to uniformly charge of lifting the small amount of liquid lubricant to the carrier particles, locally sheared When a force and heat are applied, the liquid lubricant is firmly adsorbed, and in the case of silicone or the like, seizure occurs, so that the liquid lubricant may not be effectively released from the carrier particles.

[0035] For responsible lifting amount of the liquid lubricant to the magnetic material, the amount of the liquid lubricant with respect to the binder resin in view of the effect is important. The optimum range, it added collateral is lifting the magnetic as a 0.1-7 parts by weight per 100 parts by weight of the binder resin as a liquid lubricant amount. More preferably, 0.
It is 2 to 5 parts by weight, particularly preferably 0.3 to 2 parts by weight. Lubricants carrier particles containing liquid lubricant used in the present invention, which microparticles of organic compounds or inorganic compounds granulation or by aggregating the liquid lubricant is used as a lubricant carrier 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 fluorine resin.

The inorganic compounds include SiO ₂ , Ge
_{O 2, TiO 2, SnO 2} , Al 2 O 3, B 2 O 3, oxides such as P ₂ O _5, silicates, borates, phosphates, borosilicates, aluminosilicates, Aruminohou acid Salts, metal oxide salts such as aluminoborosilicate, tungstate, molybdate, tellurate, and composite compounds thereof, silicon carbide, silicon nitride, amorphous carbon, and the like. These may be used alone or as a mixture. As the inorganic compound fine powder, an inorganic compound fine powder produced by a dry method and a wet method is used.

The dry method referred to here is a method for producing a fine inorganic compound powder produced by vapor phase oxidation of a halide. For example, the basic reaction formula in the method utilizing the thermal decomposition oxidation reaction of halide gas in oxygen and hydrogen is as follows. _{MX n + 1 / 2nH 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 , Ge
When Cl ₄ , SiCl ₄ , POCl ₃ , and BBr ₃ are used, Al ₂ O ₃ , TiO ₂ , GeO ₂ , SiO ₂ , P ₂ O ₅ , and B ₂
O ₃ is obtained. At this time, if a mixture of halides is used, a composite compound can be obtained. Alternatively, a fine powder can be obtained by a dry method by applying a manufacturing method such as thermal CVD or plasma CVD. Among them, SiO ₂ , Al ₂ O ₃ and Ti
O _{2 and the} like are preferably used.

On the other hand, as a method for producing the inorganic compound fine powder used in the present invention by a wet method, various conventionally known methods can be applied. For example, decomposition of sodium silicate by an acid as shown in the following formula: Na ₂ O.XSiO ₂ + HCl + H ₂ O → SiO ₂ .nH
₂ O + NaCl Decomposition of sodium silicate with ammonium salts or alkali salts, method of producing alkaline earth metal silicate from sodium silicate, and then decomposing with acid to form silicic acid, ion exchange of sodium silicate solution There are a method of using silicic acid with a resin, a method of using natural silicic acid or 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 + RO
H 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 metal alkoxides. Of these, inorganic compounds, particularly metal oxides, are preferred because they have an appropriate electric resistance value. In particular, Si, Al and T
An oxide or a composite oxide of i is preferred.

Further, a material whose surface has been previously hydrophobized with a coupling agent or the like may be used. However, some liquid lubricants tend to be excessively charged when they cover the surface of the toner particles. When a non-hydrophobic material is used as the carrier particles, it is possible to perform appropriate leakage of electric charges and maintain good developability. Therefore, the use of carrier particles that have not been subjected to a hydrophobic treatment is also one of the preferred embodiments. The particle size of the charge of fine particles, preferably 0.001～20Myuemu, especially 0.005~10μm good.

The specific surface area of the carrier particles by nitrogen adsorption measured by the BET method is 5 to 500 m ² / g, preferably 10 to 400 m ² / g, and more preferably 20 to ³ m ² / g.
50 m 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 size. The amount of the liquid lubricant in the lubricant carrier particles is 20 to 90% by weight, preferably 27 to 90% by weight.
-87% by weight, particularly preferably 40-80% by weight.

If the amount of the liquid lubricant is less than 20% by weight, good lubricity and releasability are not provided to the toner particles. For this reason, when a large amount of lubricant carrier particles is added to the toner, the developability is deteriorated. Easy to become unstable. If it exceeds 90% by weight, it is difficult to obtain lubricant carrier particles containing the liquid lubricant uniformly. Conventionally, methods of adsorbing silicone on SiO ₂ , Al ₂ O _3, TiO, or the like have been proposed. However, these methods are too strong in adsorption, so that the liquid lubricant hardly appears on the surface of the toner particles, and the toner particles are sufficiently absorbed. Lubricity and releasability cannot be imparted, and the lubricant carrier particles are not effective 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 liquid lubricant can be released while holding the liquid lubricant. It is also preferred that the components be larger than the particle size of the toner particles. Since these lubricant carrier particles contain a large amount of liquid lubricant and are brittle, a part thereof is broken during the production of the developer, and is uniformly dispersed in the toner particles. In addition, the liquid lubricant is released to lubricate the toner particles. And release properties. On the other hand, since the lubricant carrier particles are present in the toner particles while maintaining the ability to hold the liquid lubricant, the particle size in the toner particles is 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 are not deteriorated. On the other hand, even if the liquid lubricant is partially released from the surface of the toner particles, the lubricant can be replenished from the lubricant carrier particles, so that the releasability and lubricity of the toner particles can be maintained for a long period of time. These lubricants carrier particles, droplets of a solution such as diluted with a liquid lubricant, or any solvent in a mixer can be granulated by a method of adsorbing the charge of fine particles, the solvent is volatilized after granulation Furthermore, you may grind | pulverize as needed. Or in a liquid lubricant or a dilution thereof is added to the charge of particles using a kneader and kneaded, can be milled and granulated as necessary, the solvent is a method for subsequently volatilized used.

The lubricant carrier particles as described above are used as binder resin 1
It is preferably contained in an amount of 0.01 to 50 parts by weight, more preferably 0.05 to 50 parts by weight, particularly preferably 0.1 to 20 parts by weight with respect to 00 parts by weight. If the amount is less than 0.01 part by weight, lubrication and release effects cannot be obtained, and if it exceeds 50 parts by weight, problems tend to occur in charging stability and productivity.
As the lubricant carrier particles in the present invention, those obtained by impregnating or enclosing a liquid lubricant in a porous powder can be used.
Examples of the porous powder used in the present invention include molecular minerals represented by zeolite, clay minerals such as bentonite, aluminum oxide, titanium oxide, zinc oxide, and resin gel. The particle size of a porous powder, such as a resin gel, which does not disintegrate in the kneading step during toner production, is not limited.

On the other hand, the particle size of the porous powder that is difficult to disintegrate is preferably 15 μm or less as the primary particle size. 15 μm
When the ratio is more than 1, the dispersion in the toner particles tends to be uneven. Also, the BE of the porous powder before impregnation with the liquid lubricant is used.
Specific surface area by nitrogen adsorption measured by T method is 10 to 50 m
It is preferably ² / g. If it is less than 10 m ² / g, it is difficult to hold a large amount of liquid lubricant, and if it exceeds 50 m ² / g, the pore diameter is too small and the pores cannot be sufficiently impregnated with the liquid lubricant.

As a method for impregnating the porous powder with the liquid lubricant, the porous powder can be produced by subjecting the porous powder to a reduced pressure treatment and immersing the porous powder in the liquid lubricant. The amount of the porous powder impregnated with the liquid lubricant was 0.1 to 100 parts by weight of the binder resin.
It is preferable to mix in the range of 1 to 20% by weight. 0.1
When the amount is less than 20% by weight, the lubricity and the releasability are not improved. On the other hand, when the amount is more than 20% by weight, a problem is likely to occur in the charge stability of the developer. In addition, other than these, the liquid lubricant is dispersed in capsule-type lubricant carrier particles containing the liquid lubricant and the inside,
Included, swollen or impregnated resin particles are also used.

In the present invention, it is necessary to disperse the liquid lubricant as the lubricant carrier particles in the toner particles. However, since the lubricant carrier particles and their disintegration products 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 used by adsorbing it on various carrier particles, and the above method is superior in uniform dispersibility as compared with a method of simply adding silicone or the like directly.

However, the purpose of the present invention is not to simply improve the dispersibility, but it is necessary to release the liquid lubricant from the carrier particles to effectively exert the lubricating effect and the releasing effect. It is important that the liquid lubricant has a sufficient holding strength to prevent excessive release of the liquid lubricant. It is preferable to use a lubricant carrier particles in the present invention in order that the lubricant carrier particles is responsible lifting various carrier particles a liquid lubricant is used. The presence of the magnetic substance or other fine particles on or near the surface of the toner particles makes it possible to appropriately adjust the amount of the liquid lubricant on the surface of the toner particles.

The liquid lubricant is released from the lubricant carrier particles and migrates to the surface of the toner particles. However, if the holding power of the carrier particles is strong, the liquid lubricant is hardly released, and therefore the migration to the surface of the toner particles is prevented. Therefore, good lubricity and releasability of the toner particles cannot be obtained. Conversely, if the holding power of the carrier particles with respect to the liquid lubricant is weak, the liquid lubricant is easily released, and therefore excessively migrates to the surface of the toner particles, so that the chargeability of the developer becomes unstable and the developability becomes poor. Cause problems.
Further, the fluidity of the developer deteriorates, and problems such as uneven image density tend to occur. Further, if the liquid lubricant is released from the carrier particles, the lubricating and releasing effects of the developer are lost.

In the present invention, the liquid lubricant is appropriately released from the carrier particles because the liquid lubricant retaining force of the lubricant carrier particles is appropriate. Therefore, even if the liquid lubricant separates from the surface of the toner particles, the liquid lubricant is gradually removed. Since the toner particles are replenished, the lubricity and the releasability of the toner particles are maintained. In addition, the presence of carrier particles such as magnetic substances and fine particles on or near the surface of the toner particles makes it possible to re-adsorb the liquid lubricant that has migrated to the surface of the toner particles, thereby preventing excessive seepage of the liquid lubricant. I can do it. Therefore, the presence of the carrier particles on or near the surface of the toner particles is important for maintaining an appropriate amount of the liquid lubricant on the surface of the toner particles. That is, although the excess liquid lubricant is absorbed, the consumed liquid lubricant can assist the function of being quickly replenished.

As described above, the effects of the lubricity and the releasability of the developer of the present invention reach an equilibrium state 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 the liquid lubricant does not excessively come out on the surface of the toner particles because the liquid lubricant is in an equilibrium state with the adsorption by the carrier particles. On the other hand, 30
By giving a heat history of up to 45 ° C., it is preferable since the developer can exhibit the maximum effect in a stable state by shortening the period. Further, since the state is equilibrium depending on the heat history, a certain effect is maintained and no adverse effect is caused. The heat history is added at any time after the production of the toner particles, and after the pulverization in the case of the pulverization method.

[0054] As the liquid lubricant amount Ru important that the addition of magnetic material or lubricant carrier particles as a 0.1-7 parts by weight per 100 parts by weight of the binder resin. The content is more preferably 0.2 to 5 parts by weight, and particularly preferably 0.3 to 2 parts by weight. The weight average particle size of the developer of the present invention is 4 to
It is preferable that the thickness be 10 μm in order to obtain good image quality.
When the weight average particle diameter is less than 4 μm, the aggregation of the developer becomes remarkable, and there is a problem in productivity (for example, a filling step) and handling of the developer. If it exceeds 10 μm, 100 μm
The reproduction of a dot latent image or a fine line smaller than m is not sufficient.

Examples of the type of the binder resin used in the present invention include a homopolymer of styrene such as polystyrene, poly-p-chlorostyrene and polyvinyltoluene and a substituted product thereof; styrene-p-chlorostyrene copolymer. Copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylate copolymer, styrene-methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene- Acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile- Styrene copolymers such as indene copolymers Coalescence: polyvinyl chloride, phenolic resin, natural modified phenolic 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 Resin, polyvinyl butyral resin, terpene resin, coumarone indene resin, petroleum resin, and the like.

Further, a crosslinked styrene resin is also a preferable binder resin. As a comonomer for the styrene monomer of the styrene copolymer, for example, 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 or a substituted product thereof; for example, maleic acid, butyl maleate, methyl maleate, dimethyl maleate, etc. Dicarboxylic acids having the same double bond and substituted products thereof; for example, vinyl chloride,
Vinyl esters such as vinyl acetate and vinyl benzoate; for example, ethylene-based olefins such as ethylene, propylene, butylene; vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone; Ether, vinyl ethyl ether,
Vinyl ethers such as vinyl isobutyl ether;
Are used alone or in combination.

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

In the bulk polymerization method, a polymer having a low molecular weight can be obtained by increasing the termination reaction rate by polymerizing at a high temperature, but there is a problem that the reaction is difficult to control. 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 compound in the resin composition used.

As the solvent used in the solution polymerization, xylene, toluene, cumene, cellosolve acetate, isopropyl alcohol, benzene or the like is used. In the case of a styrene monomer mixture, xylene, toluene or cumene is 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.
It is good to carry out at ° C. In the solution polymerization, it is preferable to perform the polymerization at 30 parts by weight to 400 parts by weight with respect to 100 parts by weight of the solvent. Further, it is also preferable to mix another polymer in the solution at the end of the polymerization, and several types of polymers can be well mixed.

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 almost insoluble in water is dispersed in an aqueous phase as small particles with an emulsifier, and the polymerization is carried out using a water-soluble polymerization initiator. In this method, the reaction heat can be easily controlled, and the termination reaction rate is low because the phase in which the polymerization is performed (the oil phase composed of the polymer and the monomer) and the aqueous phase are different. As a result, the polymerization rate is high. , With a high degree of polymerization. Furthermore, 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. This is advantageous as compared with other methods as a method for producing a binder resin for a toner. However, the resulting polymer tends to be impure due to the added emulsifier, and an operation such as salting out is required to remove the polymer. Therefore, suspension polymerization is a simple method.

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). As a dispersant that can be used, polyvinyl alcohol, partially saponified polyvinyl alcohol, calcium phosphate, or the like is used, and is an appropriate amount in terms of the amount of a monomer with respect to an aqueous solvent, but generally 0.05 to 100 parts by weight of an aqueous solvent. Used in 1 part by weight. The polymerization temperature is suitably from 50 to 95 ° C, but should be appropriately selected depending on the initiator used and the intended polymer. In addition, any initiator can be used as long as it is insoluble or hardly soluble in water.

As the initiator to be used, t-butyl
Oxy-2-ethylhexanoate, cumyl perpivalate, t-butyl peroxy laurate, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, di-t-butyl peroxide, t
-Butylcumyl 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-butyl peroxyazelate,
2,5-dimethyl-2,5-di (t-butylperoxy) hexane, diethylene glycol bis (t-butylperoxycarbonate), di-t-butylperoxytrimethyl adipate, tris (t-butylperoxy) triazine And vinyltris (t-butylperoxy) silane and the like, and these are used alone or in combination. The amount used is 0.05 parts by weight or more (preferably 0.1 to 1.5 parts by weight) with respect to 100 parts by weight of the monomer.

The composition of the polyester resin used in the present invention is as follows. Examples of the dihydric alcohol component include 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-1,3 hexanediol, hydrogenated bisphenol A,
A bisphenol represented by the following formula (A) and a derivative thereof;

[0064]

Embedded image

Diols represented by the formula (B):

Embedded image Is mentioned.

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

It is preferable to use a tri- or higher valent alcohol component serving as a crosslinking component together with a tri- or higher valent acid component. Examples of the trihydric or higher polyhydric alcohol component include, for example,
Sorbitol, 1,2,3,6-hexanetetrol,
1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,2
4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2
-Methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxybenzene and the like.

The trivalent or higher polycarboxylic acid component in the present invention includes, for example, trimellitic acid, pyromellitic acid, 1,2,4-benzenetricarboxylic acid,
2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,2
5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8-
Octanetetracarboxylic acid, embolic trimer acid, and their anhydrides or lower alkyl esters;

The following equation

Embedded image And polycarboxylic acids such as anhydrides or lower alkyl esters thereof and derivatives thereof.

The alcohol component used in the present invention is 40 to 60 mol%, preferably 45 to 55 mol%.
%, 60 to 40 mol% as an acid component, preferably 5%
5 to 45 mol%. Further, the content of the trivalent or higher polyvalent component is preferably 5 to 60 mol% of all the components.

From the viewpoints of developability, fixability, durability and cleaning properties, styrene-unsaturated carboxylic acid derivative copolymers, polyester resins and their block copolymers,
A grafted product, more preferably, a mixture of a styrene copolymer and a polyester resin is preferred. Further, as a binder resin for a developer used for pressure fixing, low-molecular-weight polyethylene, low-molecular-weight polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, higher fatty acid, polyamide resin, A polyester resin is exemplified. These are preferably used alone or as a mixture.

From the viewpoint of improving the releasability from the fixing member at the time of fixing and improving the fixing property, it is also preferable to include the following waxes in the developer. 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. These derivatives include oxides and block copolymers with vinyl monomers. Includes polymer or graft-modified product. In addition, alcohols, fatty acids, acid amides, esters, ketones, hydrogenated castor oil and derivatives thereof, vegetable waxes, animal waxes, mineral waxes, petrolactam and the like can also be used. The magnetic developer of the present invention is preferably used because a charge control agent can be mixed (internally added) to the developer particles or mixed (externally added) with the developer particles.

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

The following substances are exemplified as those which are controlled to be positively charged. Modified products such as nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate, and onium salts such as phosphonium salts which are analogs thereof And these lake pigments, triphenylmethane dyes and these lake pigments (as the lake-forming agent, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide) 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 charge control agents described above are preferably used in the form of fine particles. In this case, the number average particle size of these charge control agents is particularly preferably 4 μm or less, more preferably 3 μm or less. When these charge control agents are internally added to the developer, it is preferable to use 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 coloring materials that can be further added to the developer of the present invention include conventionally known carbon black and copper phthalocyanine.

The magnetic developer of the present invention has environmental stability,
A magnetic developer characterized by the present invention is obtained by stirring and mixing an organic-treated inorganic fine powder with a mixer such as a Henschel mixer in order to improve charge stability, developability, fluidity or storage stability. Can 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 are preferable, and fine silica powder is particularly preferable. For example, as the silica fine powder, both a so-called dry method produced by vapor phase oxidation of a silicon halide or a so-called wet silica produced from water glass or the like and dry silica called fumed silica can be used. However, dry silica having less silanol groups on the surface and in the interior of the silica fine powder and having less production residues such as Na ₂ O and SO ₃ ^2- is preferred.

In the case of dry silica, a fine composite powder of silica and another metal oxide is obtained by using another metal halide such as aluminum chloride or titanium chloride together with a silicon halide in the manufacturing process. It is also possible and encompasses them. In the present invention,
It is characterized by using inorganic fine powder that has been subjected to organic treatment.
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 that reacts or physically adsorbs with the inorganic fine powder, a treatment with a silane coupling agent, or a treatment with a silane coupling agent. A method of treating with a ring agent and treating with an organosilicon compound such as silicone oil at the same time.

Examples of the silane coupling agent used for the organic treatment include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, and allylphenyl. Dichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane,
Chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilyl acrylate, vinyldimethylacetoxysilane, dimethyldiethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyl Disiloxane, 1,3-diphenyltetramethyldisiloxane and dimethylpolysiloxane having from 2 to 12 siloxane units per molecule, each of the terminal units containing hydroxyl groups bonded to one silicon atom at each terminal unit And the like.

Further, aminopropyltrimethoxysilane, aminopropyltriethoxysilane having a nitrogen atom,
Dimethylaminopropyltrimethoxysilane, diethylaminopropyltrimethoxysilane, dipropylaminopropyltrimethoxysilane, dibutylaminopropyltrimethoxysilane, monobutylaminopropyltrimethoxysilane, dioctylaminopropyldimethoxysilane, dibutylaminopropyldimethoxysilane, dibutylamino Propylmonomethoxysilane, dimethylaminophenyltriethoxysilane, trimethoxysilyl-
γ-propylphenylamine, trimethoxysilyl-γ
A silane coupling agent such as -propylbenzylamine is also used alone or in combination. As a preferred silane coupling agent, hexamethyldisilazane (HMD)
S).

As the organosilicon compound, silicone oil can be used. Preferred silicone oils are those having a viscosity at 25 ° C of 0.5 to 10,000, preferably 1 to 1,000 centistokes. For example, dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene-modified Particularly preferred are silicone oil, chlorophenyl silicone oil, fluorine-modified silicone oil and the like.

As a method of treating the silicone oil, for example, the silica fine powder treated with the silane coupling agent and the silicone oil may be directly mixed using a mixer such as a Henschel mixer, or the silica A method of spraying silicone oil on fine powder may be used. Alternatively, a method of dissolving or dispersing the silicone oil in an appropriate solvent, adding a silica fine powder, mixing and removing the solvent may be employed.

The organically treated inorganic fine powder used in the present invention has a specific surface area by nitrogen adsorption of 3 as measured by the BET method.
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 from 01 to 8 parts by weight, preferably from 0.1 to 5 parts by weight, particularly preferably from 0.2 to 3 parts by weight. When the amount is less than 0.01 part by weight, the effect of improving toner aggregation is poor, and when the amount is more than 8 parts by weight, problems such as toner scattering between fine lines, contamination inside the apparatus, scratches and abrasion of the photoconductor tend to occur. is there.

In the magnetic developer of the present invention, other additives such as lubricant powders such as Teflon powder, zinc stearate powder and polyvinylidene fluoride powder, or cerium oxide powder may be used as long as they do not have a substantial adverse effect. Abrasives such as silicon carbide powder and strontium titanate powder, or fluidity-imparting agents such as titanium oxide powder and aluminum oxide powder, anti-caking agents, or carbon black powder, zinc oxide powder, tin oxide powder, etc. , And a small amount of organic fine particles and inorganic fine particles of opposite polarity 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. In the case where the absolute value of the charge amount of the developer exceeds 40μc / g, in the cleaning part, electrostatic cohesive force and electrostatic adhesion to the electrostatic latent image in charge bearing member surface of the developer particles is increased, There is a tendency for poor cleaning or developer fusion to occur.

The method of measuring the charge amount of the developer in the present invention is described below with reference to FIG. Under an environment of 23 ° C. and a relative humidity of 60%, EFV200 / 300 (manufactured by Powdertech) was used as a carrier, and 9.5 g of the carrier was used for the developer 0.5%.
g of the mixture is placed in a 50-100 ml polyethylene bottle and shaken by hand 50 times. Then add 50 to the bottom
1.0 to 1.2 g of the mixture is placed in a metal measuring container 2 having a 0-mesh screen 3 and a metal lid 4 is closed.

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

A known method can be used to prepare the magnetic developer of the present invention.
Metal salts or metal complexes, pigments or dyes as colorants,
The magnetic material and, if necessary, the charge control agent and other additives are sufficiently mixed by a mixer such as a Henschel mixer or a ball mill, and then melt-kneaded using a heat kneader such as a heating roll, kneader or extruder. A metal compound, a pigment, a dye, and a magnetic substance are dispersed or dissolved in a resin mixed with each other, and after cooling and solidifying, pulverization and classification are performed to obtain the developer of the present invention.

The weight average particle diameter (D4) of the developer can be measured by various methods, but in the present invention, the measurement was performed using a Coulter counter. That is, a Coulter Counter TA-II type (manufactured by Coulter) was used as a measuring device, and an interface (manufactured by Nikkaki) for outputting a number distribution and a volume distribution and a PC9801 personal computer (manufactured by NEC) were connected. Adjust 1% NaCl aqueous solution using graded sodium chloride.

The measuring method is as follows.
0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersing agent to 150 ml, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample was suspended was subjected to a dispersion treatment for about 1 to 3 minutes using an ultrasonic disperser, and the particle size distribution of particles of 2 to 40 μm based on the number was measured using the Coulter Counter TA-II with an aperture of 100 μm. Is measured, and
The volume distribution and the number distribution of the 40 μm particles were calculated, and the weight-based weight average particle diameter (D4: the median value of each channel was taken as the representative value of the channel) was determined from the volume distribution.

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

[0091] developer responsible bearing member for carrying the magnetic developer of the present invention is preferably covered with a resin layer containing conductive fine particles. Further, 0.2 in the surface roughness of the developer responsible lifting bodies for use in the present invention JIS center line average roughness (Ra)
It is preferably in the range of 3.0 μm. Ra is 0.2
If it is less than μm, the charge amount on the developer carrying member becomes high, and developability becomes insufficient. If Ra exceeds 3.0 μm, the developer coat layer on the developer carrier becomes uneven, resulting in uneven density on the image.

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

[0093]

Next, the present invention will be described in more detail with reference to Production Examples, Examples and Comparative Examples, which do 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 attached.
0, a transfer charging roller 114, a cleaner 116, a register roller 124, and the like. The photosensitive drum 100 is moved to −700 by the primary charging roller 117.
V (applied voltage is AC voltage -2.0 kVp
p, DC voltage -700 Vdc).

Then, the photosensitive drum 100 is exposed by irradiating the photosensitive drum 100 with a laser beam 123 by the laser generator 121. The electrostatic latent image on the photosensitive drum 100 is developed by a developing device 140 with a one-component magnetic developer, and is transferred onto a transfer material by a transfer roller 114. The transfer material on which the developer image is placed is transferred to the fixing device 12 by a transport belt 125 or the like.
6 and is fixed on the transfer material. The developer remaining on the electrostatic latent image bearing member is partially cleaned by the cleaning unit 116.

[0095] developing unit 140, in proximity to the photosensitive drum 100 as shown in FIG. 2 aluminum (hereinafter referred to as developing sleeve) nonmagnetic metals-made cylindrical developer responsible bearing member 102 of stainless steel or the like 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) or the like.

The magnet roller 1 is set 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 figure. S1 affects development, N1 regulates the amount of developer coating, S2 affects developer take-in / transport, and N2 affects developer blowing prevention. .

The elastic blade 10 serves as a member for regulating the amount of the magnetic developer adhered to and conveyed to the developing sleeve 102.
3, the developing sleeve 10 of the elastic blade 103 is provided.
The amount of the developer conveyed to the developing area is controlled by the contact pressure with respect to 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.

[0098] <Production Example of liquid lubricant responsible lifting magnetic> Magnetic iron oxide (BET value 5.5m ² /g,σs=38.5
(emu / g) 100 parts, a predetermined amount of a liquid lubricant was put into a Simpson mix muller (MPVU-2, manufactured by Matsumoto Casting Co., Ltd.), operated at room temperature for 30 minutes, and further loosened with a hammer mill. adding a liquid lubricant to obtain a responsible lifting the magnetic body (a) to. Similarly, the various liquid lubricant is responsible lifting various magnetic material. The resulting liquid lubricant shown in the following Table 1 The physical properties of the magnetic body a~h was responsible di. Also, a magnetic material a
The untreated product was designated as untreated magnetic material i, and the untreated product of magnetic material h was designated as untreated magnetic material j.

[0099] with stirring responsible fine particles to responsible lifting the <Liquid lubricant responsible production example of lifting the lubricating particles> liquid lubricant in a Henschel mixer, added dropwise which was diluted liquid lubricant in n- hexane. After completion of the dropwise addition with stirring under reduced pressure to remove the n- hexane and then to obtain a lubricating particulate a~h was responsible equity was triturated in a hammer mill liquid lubricant. The resulting liquid lubricant shown in the following Table 2 the physical properties of charge of lifting the lubricant carrier particles a~h a. The untreated silica used in the production of the lubricant carrier particles a was designated as particles i.

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

<Development example 2> 100 parts of styrene-2 ethylhexyl acrylate-n-butyl maleate half ester copolymer (copolymerization ratio 7: 2: 1, Mw = 220,000) -Negative charge control agent (monoazo dye-based chromium complex) 0.8 part-Ethylene-propylene copolymer (Mw = 6000) 4 parts A black fine powder was obtained in the same manner as in Production Example 1 using the above components. 1.8 parts by weight of hydrophobic silica fine powder (the same as in Production Example 1) was added to 100 parts of the black fine powder, and a magnetic developer B was obtained in the same manner as in Production Example 1. The physical properties of the obtained developer B are shown in Table 3 below.

<Developer comparative production example 1 > Developer production example 1 except that the magnetic substance c was used as a magnetic substance in an amount of 70 parts by weight and the amount of hydrophobic silica added was 0.6% by weight.
In the same manner as in the above, magnetic developer C was obtained. Table 3 below shows the physical properties of the obtained developer C.

<Developer Production Example 3 > Magnetic material d 120 parts Polyester resin 100 parts Monoazo dye iron complex (negative charge control agent) 2 parts Low molecular weight polyolefin (release agent) 2 parts In developer production example 1, Hydrophobic silica (1.2% by weight) was made into hydrophobic titanium oxide fine powder (dimethylsilane treated BET specific surface area: 50 m ² / g) 0.9% by weight, and magnetic materials were prepared in the same manner as in developer production example 1 except that the above materials were used. Developer D was obtained. The physical properties of Magnetic Developer D thus obtained are shown in Table 3 below.

<Developer Production Example 4 > Hydrophobic silica fine powder (hexamethyldisilazane-treated BET specific surface area 38
0 m ² / g) was added in the same manner as in Developer Production Example 1, except that 1.5% by weight of the magnetic developer E was obtained. Table 3 below shows the physical properties of the obtained magnetic developer E.

<Developer Production Example 5 > A magnetic developer F was prepared in the same manner as the developer production example 4 except that the magnetic material f was 120 parts as a magnetic material and the amount of the hydrophobic silica was 1.4% by weight. I got Magnetic developer F obtained
The physical properties of are shown in Table 3 below.

<Developer Comparative Production Example 2 > Developer production example 1 except that the weight of the magnetic material was 100 parts and the amount of hydrophobic silica added was 1.0% by weight.
In the same manner as in the above, magnetic developer G was obtained. Table 2 below shows the physical properties of the obtained magnetic developer G.

<Developer Comparative Production Example 3 > A magnetic developer H was obtained in the same manner as in the developer production example 1 except that 100 parts of the magnetic material h was used as the magnetic material. Table 2 below shows the physical properties of the obtained magnetic developer H.

<Developer Comparative Production Example 4 > A magnetic developer I was obtained in the same manner as in Developer Production Example 1, except that 100 parts of untreated magnetic substance i was used as the magnetic substance. Table 2 below shows the physical properties of the obtained magnetic developer I.

<Developer Production Example 6 > 100 parts of magnetic substance a 100 parts of styrene-n-butyl acrylate copolymer (copolymerization ratio 8: 2 Mw = 260,000) 1 part of lubricant carrier particles a 1 monoazo 2 parts of iron complex of dye (negative charge control agent) 2 parts of low molecular weight polyolefin (release agent) A black fine powder was obtained in the same manner as in Production Example 1. 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 a magnetic developer J was obtained in the same manner as in Production Example 1. Table 3 below shows the physical properties of the obtained developer J.

<Developer Production Example 7 > 100 parts of magnetic substance i 100 parts of styrene-n-butyl acrylate copolymer (copolymerization ratio 8: 2 Mw = 260,000) 4 parts of lubricant carrier particles b 4 monoazo 2 parts of iron complex of dye (negative charge control agent) 2 parts of low molecular weight polyolefin (release agent) A black fine powder was obtained in the same manner as in Production Example 1. 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 a magnetic developer K was obtained in the same manner as in Production Example 1. Table 3 below shows the physical properties of the obtained developer K.

<Developer Production Examples 8 to 13 and Developer Comparative Product
Production Example 5 > Same as developer production example 6 except that lubricant carrier particles b to h are used instead of lubricant carrier particles a, and the developer particle size and the amount of organically treated inorganic fine powder added are changed. Thus, developers L to R were obtained. The physical properties of the obtained developers L to R are shown in Table 3 below.

<Developer Comparative Production Example 6 > A developer S was obtained in the same manner as in the developer production example 7 , except that untreated particles i were used instead of the lubricant carrier particles b . The physical properties of the obtained developer S are shown in Table 3 below.

<Development Comparative Production Example 7 > Untreated magnetic material j was replaced by 1 in place of magnetic material a as the magnetic material.
A magnetic developer T was obtained in the same manner as in Developer Production Example 1 except that 00 parts were used. Table 3 below shows the physical properties of the obtained developer T.

Example 1 As an image forming apparatus, an apparatus shown in FIG. 1 was used. The electrostatic latent image charge of lifting body dark potential using OPC drum having a diameter of 30mm as Vd = -700 V, light potential VL = -2
10V. Make the gap between the photosensitive drum and the developing sleeve 3
A developing sleeve in which a resin layer having a thickness of about 7 μm and a JIS center line average roughness (Ra) of 2.2 μm having the following structure as a developer carrier is formed on a 16 mm diameter aluminum cylinder having a mirror-finished surface. Using the developing magnetic pole 950
A Gaussian urethane rubber blade having a thickness of 1.0 mm and a free length of 10 mm as a developer regulating member was contacted with a linear pressure of 15 g / cm.・ 100 parts of phenolic resin ・ 90 parts of graphite (particle size: about 7 μm) ・ 10 parts of carbon black

Next, the DC bias component Vdc = -500 V as the developing bias and the superposed AC bias component V
pp = 1600 V and f = 2000 Hz were used. The transfer roller (made of ethylene-propylene rubber in which conductive carbon is dispersed, diameter: 20 mm, contact pressure: 50 g / cm) is set at a constant speed with the peripheral speed of the photoreceptor (48 mm / sec), and +2 kV is applied as a transfer bias to the developer. Was used under the conditions 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 any omission during transfer was obtained. Also, 8
The resolution of a 1-dot latent image of 0 μm was also at a sufficiently good level. Furthermore, no abnormalities such as fusion were observed on the surface of the photoreceptor even after continuous printing of 5000 sheets.

Comparative Example 1 Using the developer T as a developer, an image was formed under the same apparatus and conditions as in Example 1. As a result, tailing was conspicuous on the image as shown in Table 4 below. Also, 80 μm
The resolution of the one-dot latent image was insufficient and an image lacking sharpness was obtained. After continuous printing of 5000 sheets, fusion of the developer was observed on the photoreceptor surface, and white spots appeared on the printed image.

Comparative Example 2 An image was formed using the same developer and conditions as in Example 1 except that the developer I was used as the developer. As a result, the image was conspicuous with a hollow portion in the line portion. Further, fusion of the developer was observed on the surface of the photoreceptor after continuous printing of 5000 sheets, and white spots appeared on the printed image.

[Examples 2 to 5 and Comparative Examples 3 and 4 ] Using developers B to G as developers, image formation was performed under the same apparatus and conditions as in Example 1. The results are shown in Table 4 below.

[Examples 6 to 13 and Comparative Example 5 ] Using developers J to R as developers, image formation was performed under the same apparatus and conditions as in Example 1. The results are shown in Table 4 below.

Comparative Example 6 An image was formed using the same developer and conditions as in Example 1 except that the developer S was used as the developer. As a result, the image was conspicuous with a hollow portion in the line portion. Further, fusion of the developer was observed on the surface of the photoreceptor after continuous printing of 5,000 sheets, and white spots appeared on the printed image.

Comparative Example 7 An image was formed using the developer H as the developer under the same apparatus and conditions as in Example 1. As a result, tailing was conspicuous on the image. In addition, an image lacking in sharpness with insufficient resolution of a one-dot latent image of 80 μm was obtained.

[0122]

[Table 1]

[0123]

[Table 2]

[0124]

[Table 3]

[0125]

[Table 4]

[0126]

[Table 5]

Criteria for evaluation of hollow spots: 極 め て: extremely good Δ: good hollows are observed in some thin lines, but good ×: fine lines cannot be resolved due to the hollow spots Evaluation criteria for tailing: ○: extremely good △: good × : Remarkable tailing 80 μm 1 dot reproducibility evaluation criteria: ○: extremely good △: good ×: no resolution and practically unusable Fusion evaluation criteria: ○: extremely good △: slight fusion is recognized but practical Acceptable ×: Appears on the image and is impractical Image density: Measured by Macbeth densitometer RD914

[0128]

According to the present invention, there is provided a magnetic developer obtained by externally adding 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 magnetization intensity of 25 ~
A magnetic material formed of a metal oxide having a mass of 40 emu / g, and the liquid lubricant is based on 100 parts by weight of the binder resin.
0.1-7 are contained parts, the toner particles has the liquid lubricant in the vicinity of its surface or surfaces, and the weight average particle diameter of the magnetic developer is a 4.0~10μm By using a magnetic developer and an image forming method using the same, there is no fusion of the developer to the photoreceptor, poor cleaning, missing during transfer, and no trailing, high resolution having good image density, and It has become possible to obtain images with high definition reproducibility.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating 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 method for measuring a triboelectric charge amount of a developer according to the present invention.

Continuation of the front page (51) Int.Cl. ⁷ identification code FI G03G 15/08 504 G03G 15/08 504A 21/10 9/08 302 21/00 310 (56) References A) JP-A-4-73659 (JP, A) JP-A-4-162049 (JP, A) JP-A-3-50562 (JP, A) JP-A-4-274444 (JP, A) JP-A-61 -279865 (JP, A) JP-A-3-63660 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/083

Claims (11)

(57) [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. The strength of magnetization in Oersted is
A magnetic material formed of a metal oxide having a particle diameter of 25 to 40 emu / g, and the liquid lubricant is used in an amount of 100 parts by weight of the binder resin.
To 0.1-7 are contained parts, the toner particles has the liquid lubricant in the vicinity of its surface or surfaces, and the weight average particle diameter of the magnetic developer 4.0~10μm A magnetic developer, characterized in that: 2. A liquid lubricant, stirring action, compression action, magnetic developer according to claim 1 which is responsible lifting more magnetic for work in a shearing action or spatula. 3. A 2 to the liquid lubricant, responsible body particle child Weight
2. The magnetic developer according to claim 1, wherein the magnetic developer is contained in the toner particles in the form of lubricant carrier particles containing 0 to 90% by weight of a liquid lubricant . 4. A liquid lubricant having a viscosity at 25 ° C. of 10
The magnetic developer according to any one of claims 1 to 3 , wherein the magnetic developer is ２０200,000 cSt. 5. A form an electrostatic latent image by charging and exposing at least an electrostatic latent image charge of lifting member, the electrostatic latent image a visible image obtained by developing with a developer on the transfer material transferred, in the image forming method of cleaning by the cleaning member thereafter the electrostatic latent image in charge bearing member surface, the charging process member in pressure contact with the electrostatic latent image charge of lifting body, at least one of the developing step, a transfer step and a cleaning step In two steps, the developer is a magnetic developer obtained by externally adding and mixing at least a binder resin, a magnetic toner particle containing a liquid lubricant and a magnetic substance, and an organically treated inorganic fine powder, The magnetic material has a magnetic field of 1
The magnetization intensity in k Oersted is 25 to 40 emu
A / g a magnetic body formed of a metal oxide, said liquid
Body lubricant 0.1 to 7 parts per 100 parts by weight of binder resin
Are contained amount unit, the toner particles has the liquid lubricant in the vicinity of its surface or surfaces, and that the weight average particle diameter of the magnetic developer is a magnetic developer 4.0~10μm An image forming method comprising: 6. An electrostatic latent image bearing member and the developer responsible lifting body is arranged with a fixed gap at the developing portion, a magnetic developer thinner than the gap in the developer responsible lifting body on thickness the image forming method according to claim 5 regulations and is conveyed to the developing unit, develops the latent image on the electrostatic latent image charge of lifting member by applying an alternating electric field in the developing unit. 7. The image forming method according to claim 5 or 6 member for regulating the developer on the developer responsible lifting member is in contact with the developer responsible lifting member via the developer. 8. The image forming method according to any one of claims 5-7 in which the developer responsible lifting body is covered with a resin layer containing conductive fine particles. 9. The image forming method according to any one of claims 5-8 electrostatic latent image charge of lifting body is an organic photoconductor. 10. The image forming method according to any one <br/> of claims 5-9 in which the transfer member is brought into contact with the electrostatic latent image charge of lifting member via the transfer material at the time of transfer. 11. The method of claim charging member for charging the electrostatic latent image in charge bearing member is in contact with the electrostatic latent image charge of lifting bodies 5-10 noise
2. The image forming method according to claim 1.