JP3265446B2 - Developer for developing electrostatic image and image forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a developer for developing an electrostatic image such as electrophotography and electrostatic printing, and an image forming method using the developer.

[0002]

2. Description of the Related Art Conventionally, electrophotography has been disclosed in U.S. Pat. No. 2,297,691, Japanese Patent Publication No. 42-23910.
Many methods are known as described in Japanese Patent Application Laid-Open Publication No. Sho. 43-24748, and the like. Generally, a photoconductive substance is used to form an electric latent image on a photoreceptor by various means. The latent image is developed with toner to form a visible image, and the toner image is transferred to a transfer material such as paper as necessary, and then the toner image is fixed on the transfer material by heat and pressure. To obtain a copy, and the remaining toner that has not been transferred onto the photoreceptor is cleaned by various methods, and the above-described steps are repeated.

In recent years, such a copying apparatus has been used not only as a copy machine for office work for simply copying an original manuscript, but also for copying a high-resolution image such as a digital printer or a graphic design as a computer output. Started to be used.

[0004] Therefore, higher reliability has been strictly pursued, and the required performance has become higher. Accordingly, if the performance improvement of the image forming method including the toner cannot be achieved, a more excellent machine will be established. It's gone.

The most important performance required for toner in digital printers and copying of high-definition images is fixing performance.

Various methods and apparatuses have been developed for the fixing step, but the most common method at present is a pressure heating method using a heat roller.

In the pressure heating method using a heating roller, fixing is performed by allowing the toner image surface of a sheet to be fixed to pass through the surface of a heat roller formed of a material having a releasing property with respect to the toner while contacting the surface under pressure. It is what you do. In this method, since the surface of the heat roller and the toner image of the sheet to be fixed come into contact with each other under pressure, the thermal efficiency at the time of fusing the toner image onto the sheet to be fixed is extremely good, and the fixing can be performed quickly. And is very effective in high speed electrophotographic copiers. However, in the above method, since the surface of the heat roller and the toner image come into contact with each other under pressure in a molten state, a part of the toner image adheres to and transfers to the surface of the fixing roller, thereby fouling the next sheet to be fixed ( Offset phenomenon). Preventing toner from adhering to the surface of the heat fixing roller is one of the essential conditions of the heat roller fixing method.

In recent years, a fixing device has been put into practical use which comprises a pressing member which is opposed to a heating roller and is in pressure contact with a heating member, and in which a recording material is brought into close contact with the heating member via a film. However, since the toner surface is melted, the offset phenomenon is more likely to occur, and it is necessary to prevent the offset phenomenon.

JP-A-52-3304, JP-A-52-3304
JP-A-3305, JP-A-57-52574, JP-A-61-138259, JP-A-56-8705.
No. 1, JP-A-63-188158, JP-A-6-188158
Japanese Patent Application Laid-Open No. 3-113558 discloses a technique in which a wax is contained in a toner.

[0010] Waxes are used for improving the anti-offset property of the toner and the fixing property at low temperatures. However, while improving these performances, the blocking resistance is deteriorated, the developability is deteriorated when exposed to heat due to the temperature rise of a copying machine, etc., and the developability is deteriorated due to the blooming of wax when left for a long period of time. Or worse.

Further, these waxes are hard to be uniformly dispersed in the toner, and the loose or unevenly distributed wax tends to adversely affect the developability and the like, and there is still room for improvement.

On the other hand, a corona discharger is known as a charging means in an electrophotographic apparatus or the like. However, the corona discharger needs to apply a high voltage, and thus has a problem that a large amount of ozone is generated.

Recently, the use of contact charging means without using a corona discharger has been studied. Specifically, a voltage is applied to a conductive roller serving as a charging member, and the roller is brought into contact with a photosensitive member serving as a member to be charged, thereby charging the surface of the photosensitive member to a predetermined potential. If such a contact charging unit is used, the voltage can be reduced as compared with a corona discharger, and the amount of ozone generated decreases.

For example, Japanese Patent Publication No. 50-13661 proposes charging a photosensitive paper by applying a low voltage to a photosensitive paper using a roller whose core is covered with a dielectric material made of nylon or polyurethane rubber. .

However, as described above, the toner whose fixing property is improved by the waxes is liable to undergo plastic deformation. Therefore, in the image forming process in which the toner is pressed against the photosensitive member by contact charging, Fusing and filming of the toner on the contact charging member and the photoconductor are likely to occur. In extreme cases, image defects are likely to occur.

As for the addition of resin fine particles to a developer, Japanese Patent Application Laid-Open No. Sho 60-186854 proposes to add a spherical or nearly spherical polymer particle smaller than a toner particle to a developer. I have.

When a developer was prepared and examined in the same manner as above, the effect of preventing fusion of the toner on the photoreceptor was small, and in a device using contact charging, the contact charging device was contaminated.
Charging unevenness was likely to occur.

On the other hand, in recent years, small and inexpensive personal use copying machines and laser printers have emerged. In these small machines, from the maintenance-free standpoint, a cartridge system in which a photosensitive member, a developing device, a cleaning device and the like are integrated. It is desirable to use a magnetic one-component developer because the structure of the developing device can be simplified as the developer.

In such a method using a magnetic one-component developer, it is necessary that the developer has a uniform chargeability in order to obtain an image of good quality. For that purpose, the thickness of the developer layer is regulated by pressing using a regulating blade formed of an elastic material such as silicone rubber,
A method of applying a developer on a developer carrier such as a developing sleeve may be used.

In the case where the above-mentioned method is used, in particular, the toner whose fixing property is improved by the above-mentioned waxes tends to be plastically deformed. May cause
It is likely to cause image defects such as image density unevenness and image white spots.

In Japanese Patent Application Laid-Open No. 4-274444,
Although it has been proposed to treat the resin fine particles with an oil, the present invention has a sufficient effect on omission during transfer, but has a sufficient fixing property and anti-offset property in a severe use environment, and has been applied to a developing sleeve and a regulating blade. It was difficult to satisfy all the effects of preventing toner fusion.

[0022]

SUMMARY OF THE INVENTION An object of the present invention is to provide a developer for developing an electrostatic image and an image forming method which solve the above-mentioned conventional problems.

That is, an object of the present invention is to provide a developer for developing an electrostatic image which can be fixed at a low temperature, and has excellent offset resistance and blocking resistance.

Further, an object of the present invention is to develop an electrostatic image holding member (photosensitive member), a developer carrying member (developing sleeve) and a developer regulating member (regulating blade) which does not cause toner fusion. An object of the present invention is to provide a developer and an image forming method.

[0025]

According to the present invention, there is provided an electrostatic charge composed of toner particles containing at least a binder resin, a hydrocarbon wax and a colorant, resin fine particles smaller than the toner particle size, and inorganic fine powder. An image developing developer, wherein the hydrocarbon wax has an onset temperature in a DSC curve at a temperature rise in a range of 65 to 105 ° C, a peak temperature in a range of 75 to 120 ° C, and the resin fine particles. Has been surface-treated with a silicone oil having a viscosity of 50 to 60,000 cSt, and has a Vickers hardness of 5.0 to 30.
0 kg / mm ² with an average particle size of 0.05 to 2.0 μm
m, which relates to a developer for developing an electrostatic image.

Further, according to the present invention, there is provided a charging step in which a charging member to which a voltage is applied from the outside is brought into contact with an electrostatic latent image holder to perform charging, and an electrostatic latent image is formed on the charged electrostatic latent image holder. An image forming method comprising the steps of: developing a latent image formed on the electrostatic latent image holding member; and regulating the developer on a developer carrier by a developer regulating member to develop the electrostatic latent image. The developer is an electrostatic charge image developing developer composed of toner particles containing at least a binder resin, a hydrocarbon wax and a colorant, resin fine particles smaller than the toner particle size, and inorganic fine powder; The onset temperature at the time of temperature rise in the DSC curve of the hydrocarbon wax is 65 to 65.
105 ° C., the peak temperature is in the range of 75 to 120 ° C., and the resin fine particles have a viscosity of 50 to 60,000 c.
The present invention relates to an image forming method which has been surface-treated with St silicone oil, has a Vickers hardness of 5.0 to 30.0 kg / mm ² and an average particle size of 0.05 to 2.0 μm.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION The wax used in the present invention has an onset temperature of 6 when the temperature is raised in a DSC curve of the wax.
It is characterized by being at 5 to 105 ° C. By using such a wax, a developer having excellent blocking resistance and fixability can be obtained.

When the onset temperature is lower than 65 ° C., the toner particles undergo plastic changes from a relatively low temperature, so that the blocking resistance is poor, and the developing property is liable to be degraded with increasing temperature. On the other hand, when the temperature exceeds 105 ° C., the rate of plastic change by heating becomes slow, and the low-temperature offset resistance and the fixing property become poor.

Further, the wax used in the present invention is characterized in that the endothermic peak temperature at the time of temperature rise in the DSC curve is in the range of 75 to 120 ° C., whereby good fixability and high-temperature offset resistance can be obtained. . However, when the endothermic peak temperature is lower than 75 ° C., the wax component is dissolved in the binder resin before the temperature becomes high, and it is difficult to obtain sufficient offset resistance at high temperatures. On the other hand, 120 ° C
When the ratio exceeds the above range, it is difficult to obtain a sufficient fixing property.

That is, since the binder resin for the developer used for the heat fixing enters a viscoelastic region where the fixing can be performed from about 100 ° C., the melting of the wax component in this temperature region causes the plastic effect on the resin. , The fixability is improved, the releasing effect can be sufficiently exhibited, and the offset resistance can be improved. Therefore, it does not wrap around the fixing roller or the film, and does not rely on the separation claw, so that it does not easily form a nail mark, does not stain the pressure roller, and does not wrap around the pressure roller.
As long as the above condition is satisfied, peaks may be present in other regions.

Further, the wax used in the present invention has a number average molecular weight (Mn) of 200 to 2500 and a weight average molecular weight (Mn).
More preferably, w) is 400 to 5000 and Mw / Mn is 3 or less.

By having the molecular weight in the above range, the developer can have preferable thermal characteristics. That is, when the molecular weight is smaller than the above range, the composition is susceptible to thermal effects excessively, and the blocking resistance and the developability are deteriorated. When the molecular weight is larger than the above range, heat from the outside cannot be used effectively, and it is difficult to obtain excellent fixing properties and offset resistance. When Mw / Mn is larger than 3, the melting behavior is not sharp due to heat because of a wide molecular weight distribution, and it is difficult to obtain a region satisfying both good fixing property and offset resistance.

Further, according to the present invention, the hydrocarbon wax is represented by the following formula (1), (2) or (3)

[0034]

Embedded image [Where x represents an average value and is 35 to 150]. ]

[0035]

Embedded image [In the formula, x represents an average value and is 35 to 150, z represents an average value and is 1 to 5, and R represents hydrogen or a carbon number of 1 to 1.
Indicates 0 alkyl groups. ]

[0036]

Embedded image [In the formula, y represents an average value and is 35 to 150. It is more preferable to use a long-chain hydrocarbon compound represented by the following formula:

The hydrocarbon wax having the above structure is obtained, for example, by polymerizing ethylene using a Ziegler catalyst, and after the polymerization is completed, oxidizing to form an alkoxide of the catalyst metal and polyethylene. Thereafter, hydrolysis is performed to obtain a hydrocarbon wax represented by the formula (1). The hydrocarbon wax was reacted with a substance having an epoxy group to obtain a hydrocarbon wax represented by the formula (2). The hydrocarbon wax of the formula (3) is obtained by oxidizing the hydrocarbon wax of the formula (1).

The hydrocarbon waxes thus obtained have a small number of branches and a sharp molecular weight distribution, and do not adversely affect images.

The hydrocarbon wax used in the present invention contains 30% by weight of a hydrocarbon compound having no functional group.
Less than (more preferably 25% by weight or less) may be mixed.

Further, in the present invention, it is more preferable to use the hydrocarbon wax of the above formula (1) which is excellent in dispersibility with the binder resin.

As described above, the toner particles of the present invention can satisfy the fixing performance and the offset resistance at a high level, but on the other hand, the toner particles exhibiting excellent fixing performance at a low temperature are easily affected by heat. Therefore, when a large number of printouts are performed in a high-temperature environment, a plastic change is likely to occur when the temperature around the developing device rises. When the toner particles in such a state are pressed between the developing sleeve and the regulating blade as described above, toner fusion occurs on the developing sleeve and the regulating blade, which causes a decrease in image density and white spots. .

Further, when the toner particles having excellent fixability at a low temperature as described above are used in the image forming method for charging the photosensitive member using the contact charging member, the toner is fused to the photosensitive member. Is more likely to occur.

On the other hand, in the toner of the present invention, it is an essential condition that inorganic fine powder is added as an additive. One of the purposes is to improve the fluidity of the developer by reducing the cohesive force between toner particles, maintain stable chargeability, and further improve the occurrence of toner bridging in the developing device. That's why.

Further, the inorganic fine powder used in the present invention includes:
It is preferable that the hydrophobic treatment is performed with a silicon compound.
By adding the hydrophobicized inorganic fine powder to the toner particles to form a developer, the charge of the developer is stabilized even in various environments, and a good image can be obtained.

However, when an inorganic fine powder is added as an additive, when a large number of printouts are performed, the developer is rubbed against a developer carrier (a so-called developing sleeve) or a regulating blade, so that the toner particle surface is Release of inorganic fine powder from the powder may increase.

Since the free inorganic fine powder has a small particle size and a high charge amount, it easily adheres to the developing sleeve.
In particular, in a developing method in which the regulating blade is in contact with the developing sleeve, it causes damage to the developing sleeve and the regulating blade, and causes toner fusion to the developing sleeve and the regulating blade.

Since the fine resin particles used in the present invention have a fixed viscosity on the surface and are treated with silicone oil, the above-mentioned free inorganic fine powder can be adsorbed on the surface. This has the effect of making it difficult for toner to fuse to the sleeve and the regulating blade.

Further, since a constant amount of silicone oil is constantly supplied from the surface of the resin fine particles to the developing sleeve and the regulating blade, it is possible to impart a releasing property between the developing sleeve and the regulating blade and the toner particles, and it is possible to provide wax. The effect of improving the fixability due to the effect is easy to cause a plastic change, and toner fusion is relatively easy to occur.-Even if toner particles are used, toner fusion to a developing sleeve or a regulating blade hardly occurs.

In addition, by regulating the viscosity of the silicone oil, the developing sleeve and the regulating blade are not excessively contaminated with the silicone oil, and a stable image can be maintained even when a large number of printouts are made. is there.

In the present invention, the resin fine particles treated with the silicone oil act as a spacer between the toner particles and the developing sleeve or the regulating blade, so that the toner particles do not come into contact with the developing sleeve or the regulating blade, or hardly come into contact therewith. Therefore, it is considered that the toner is hardly fused.

The silicone oil used in the present invention is
The viscosity is 50-60,000 cSt, more preferably 1,
Those having 200 to 30,000 cSt are used.

If the viscosity is less than 50 cSt, the viscosity of the silicone oil is too low and the ability to take in free inorganic fine powder is low. Also, because of low viscosity and good fluidity,
It is difficult to be carried on the surface of resin fine particles.

If it is larger than 60,000 cSt,
Since the viscosity is too high, the silicone oil does not disperse evenly and agglomerates adhere thereto, so that aggregates are easily generated in the developer.

The fine resin particles used in the present invention preferably have an average particle diameter of 0.05 to 2.0 μm, more preferably 0.1 to 1.5 μm.

When the average particle size is smaller than 0.05 μm,
The tribo of the developer is high, and the charge-up is easily performed, and the image density is easily reduced. In addition, the effect as a spacer is hardly obtained because the particle diameter is too small. When the average particle size is larger than 2.0 μm, the difference between the particle size of the toner particles and the toner particles is small, and the fine resin particles adhere to the surface of the toner particles. And the effect of preventing fusion of the toner to the developing sleeve, the regulating blade, and the photoconductor is small.

The fine resin particles used in the present invention preferably have a surface area and a sphericity of 0.50 to 0.90, and when compared with a true sphere, as shown schematically in FIG. As a result, the force for holding the silicone oil on the surface of the resin fine particles is increased, and even under severe conditions where the generation of free inorganic fine powder is extremely large, it is possible to improve the fusion of the toner to the developing sleeve and the regulating blade. .

If the sphericity of the surface area is greater than 0.90, a large amount of silicone oil cannot be carried on the surface due to the small specific surface area of the resin fine particles. In some cases, a sufficient effect for preventing fusion of the toner cannot be obtained. 0.50
If it is smaller, the resin fine particles have many irregularities on the surface, so that the convexities on the surface of the resin fine particles are easily chipped during mixing with the toner particles or during the developing process, and there are many fragments of the resin fine particles in the developer. This may cause image defects and the like.

The Vickers hardness of the fine resin particles used in the present invention is preferably 5.0 to 30.0 kg / mm ² . If the Vickers hardness is higher than 30.0 kg / mm ² , the resin fine particles have high hardness, and the resin fine particles themselves may damage the developing sleeve and the charging member. In some cases, it is difficult to take the toner into the inside of the fine particles, and the effect of preventing fusion of the toner to the developing sleeve or the regulating blade is small. Vickers hardness is 5.0 kg / mm ²
If it is smaller, the hardness of the resin fine particles is too low, and the deformation between the developing sleeve and the regulating blade or between the contact charging member and the photoreceptor is large. It may not be possible, the ability to take in the inorganic fine particles in a free state is reduced, and the effect may be small.

The resin fine particles used in the present invention are produced by a soap-free polymerization method, an emulsion polymerization method or the like. Preferably, resin fine particles obtained by polymerizing monomers such as styrene, acrylic acid, methyl methacrylate, butyl acrylate, and 2-ethylhexyl acrylate alone or in combination of two or more thereof exhibit a good effect. Further, it may be crosslinked with divinylbenzene or the like.

The particle size of the resin fine particles in the present invention can be measured by various methods. In the present invention, the measurement was performed using an electron micrograph. That is, the electron microscope S-
800 (Hitachi, Ltd.) at a magnification of 10,000 to 20,000 times, and randomly select 1
00 to 200 pieces were extracted, the diameters of the respective convex portions were measured using an instrument such as a caliper, and the average was defined as the particle size of the resin fine particles.

The silicone oil which can be used for treating the resin fine particles used in the present invention is generally represented by the following formula:

[0062]

Embedded image R: a C _1-3 alkyl group R ′: a silicone oil-modified group such as alkyl, halogen-modified alkyl, phenyl, modified phenyl R ″: a C _1-3 alkyl group or alkoxy group

Examples include dimethyl silicone oil, alkyl-modified silicone oil, α-methylstyrene-modified silicone oil, chlorophenyl silicone oil, and fluorine-modified silicone oil. The silicone oil preferably has a viscosity at 25 ° C. of about 50 to 60,000 cSt.

A known technique is used for the method of treating the silicone oil. For example, the resin fine particles and the silicone oil may be directly mixed using a mixer such as a Henschel mixer, or the silicone oil may be sprayed on the resin fine particles. Depending on the method.

When the viscosity of the silicone oil is high, the silicone oil is finely dispersed or dissolved in a dispersant such as ethanol or a solvent using a dispersing machine such as a homogenizer, and then the above-described known technique is used. And then drying at a temperature equal to or lower than the Tg of the resin fine particles.

The treatment amount of the silicone oil is preferably 1 to 40% by weight, more preferably 3 to 25% by weight, based on the resin fine particles.

The measurement of the Vickers hardness (Hv) of the resin fine particles is performed as follows.

First, about 0.3 g of resin fine particles were weighed and molded using a tablet molding machine under a pressure of 400 (kg / cm ² ) for 5 minutes to obtain a diameter of 10 to 15 mm and a thickness of 2 to 2.5 mm.
The resin fine particles are molded. The Vickers hardness (Hv) of the molded resin fine particles is measured using a micro hardness meter (manufactured by Akashi Seisakusho) under the conditions of a load of 25 g and a holding time of 20 seconds.

The molded resin fine particles are allowed to stand for 24 hours in an environment at room temperature of 25 ° C. and a humidity of 60% RH, and then measured under the same environment.

The sphericity (Ψ) of the surface area of the resin fine particles is defined as follows.

[0071]

(Equation 1)

The actual measurement of the BET specific surface area is performed, for example, by using QUAN
When the specific surface area meter Autosorb 1 manufactured by TACHROME is used, examples of the measuring method include the following.

About 0.3 g of resin fine particles are weighed in a cell,
Deaeration is performed at a temperature of 40 ° C. and a degree of vacuum of 1.0 × 10 ⁻³ mmHg for 1 hour or more. Thereafter, nitrogen gas is adsorbed in a state of being cooled by liquid nitrogen, and a value is obtained by a multipoint method.

The surface area assuming that the fine resin particles are true spheres is, for example, an electron micrograph (× 1000) of the fine resin particles.
From 0), 100 resin fine particle images are randomly selected, their major diameters are measured, and the average diameter value is defined as the diameter when the resin fine particles are assumed to be true spheres. Based on this diameter, the radius γ of the resin fine particles is determined, and further, the surface area (4πγ ² ) of the resin fine particles is determined. In addition, the volume of resin particles

[0075]

(Equation 2) And the weight of the resin fine particles is determined from the density of the resin fine particles and the volume. From the obtained surface area and the weight, the surface area (m ² / g) assuming that the resin fine particles are spherical is determined.

The onset temperature and peak temperature in the DSC curve of the hydrocarbon wax used in the present invention are as follows:
It can be obtained from a DSC curve measured by a differential scanning calorimeter. For example, DSC-7 manufactured by PerkinElmer can be used as the measuring device.

The measuring method is ASTM D3418-82.
Perform according to. The DSC curve used in the present invention is obtained by taking a pre-history by raising the temperature once, and then measuring the temperature by 10 ° C./min.
After the temperature is lowered in the range of 0 to 200 ° C., a DSC curve measured when the temperature is raised is used. The definition of each temperature is defined as follows.

(Onset temperature at the time of raising the temperature of the wax) See FIG. 2. The lowest temperature at which the curve differential value becomes maximum (the peak temperature at the time of raising the temperature of the wax).

The content of these hydrocarbon waxes is within 20 parts by weight based on 100 parts by weight of the binder resin.
It is effective to use it in an amount of 0.5 to 10 parts by weight, and it may be used in combination with other waxes as long as the wax is not adversely affected.

The molecular weight of the hydrocarbon wax used in the present invention can be measured by the following method.

(GPC Measurement Conditions) Apparatus: GPC-150C (Waters) Column: GMH-HT 30 cm double (manufactured by Tosoh Corporation) Temperature: 135 ° C. Solvent: o-dichlorobenzene (0.1% ionol added) Flow rate: 1. 0 ml / min sample: 0.4 ml of 0.15% sample is injected

Measurement is performed under the above conditions, and the molecular weight of the sample is calculated using a molecular weight calibration curve prepared from a monodispersed polyester standard sample. In addition, Mark-Hou
It is calculated by converting to polyethylene using a conversion formula derived from the wink viscosity formula.

Particularly preferred among the inorganic fine powders used in the present invention are those produced from so-called dry method or fumed silica produced by vapor phase oxidation of a silicon halide compound, dry silica, and water glass. Both so-called wet silicas that can be used can be used. Among them, fewer silanol groups on the inner surface and the silica fine powder, also Na ₂ O, who dry silica without producing residue of SO ₃ ^2-like. In the case of fumed silica, a composite fine powder of silica and another metal oxide can be obtained by using another metal halide such as aluminum chloride or titanium chloride together with a silicon halide in the production process. In the present invention, the inorganic fine powder also includes them.

The average particle size of the inorganic fine powder is preferably in the range of 0.001 to 2 μm,
Particularly preferably, fine silica powder in the range of 0.002 to 0.2 μm is used.

The inorganic fine powder used in the present invention is preferably hydrophobic.

For the hydrophobizing treatment, conventionally known hydrophobizing agents and methods such as a silane coupling agent are used. As a more preferable hydrophobizing agent, a silicon compound having an organosiloxane unit such as silicone oil or silicone varnish can be used.

The developer of the present invention is preferably a one-component developer having a magnetic toner containing a magnetic material in toner particles. In this case, the magnetic material also serves as a colorant. Examples of the magnetic substance contained in the magnetic toner include iron oxides such as magnetite, hematite, and ferrite; metals such as iron, cobalt, and nickel; or these metals and aluminum, cobalt, copper, lead, magnesium, tin, and the like.
Examples include alloys with metals such as zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium and mixtures thereof.

[0088] magnetic material preferably has a BET specific surface area by the nitrogen adsorption method 1-20 m ² / g, especially 2.5~12m ² /
g is good. Further, magnetic powder having a Mohs hardness of 5 to 7 is preferable. The content of the magnetic powder is 10 to 7 with respect to the weight of the toner.
0% by weight is good.

These magnetic materials have an average particle size of 0.1 to 2
μm, preferably 0.1 to 0.5 μm, and the amount contained in the toner is 20 to 200 parts by weight, particularly preferably 40 to 100 parts by weight, per 100 parts by weight of the resin component. 150 parts by weight is even better.

Other colorants that can be used in the developer include any suitable pigments or dyes.

Examples of the pigment include carbon black, aniline black, acetylene black, naphthol yellow, hansa yellow, rhodamine lake, alizarin lake, bengara, phthalocyanine blue, indanthrene blue and the like. These are used in an amount sufficient to maintain the optical density of the fixed image. It is preferable to use 0.1 to 20 parts by weight, preferably 1 to 10 parts by weight of the pigment based on 100 parts by weight of the resin. A dye is further used for the same purpose. For example, there are azo dyes, anthraquinone dyes, xanthene dyes, methine dyes,
It is preferable to use 0.1 to 20 parts by weight, preferably 0.3 to 10 parts by weight of the dye based on 100 parts by weight of the resin.

As the binder resin used in the developer of the present invention, the following binder resins can be used.

For example, homopolymers of styrene such as polystyrene, poly-p-chlorostyrene and polyvinyltoluene and their substituted products; styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene Copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, 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 Copolymers: 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, polyamide resin, furan resin, epoxy resin , Xylene resin, polyvinyl butyral, terpene resin, cumarone indene resin, petroleum resin and the like can be used. Preferred binders include styrene copolymers or polyester resins.

Examples of comonomers for the styrene monomer of the styrene copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, and the like.
Duplex such as dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, etc. A monocarboxylic acid having a bond or a substituted product thereof;
For example, dicarboxylic acids having a double bond such as maleic acid, butyl maleate, methyl maleate, dimethyl maleate and the like, and substituted products thereof;
Vinyl esters such as vinyl acetate and vinyl benzoate; ethylene-based olefins such as ethylene, propylene and butylene; vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone; vinyl methyl ether and vinyl Vinyl monomers such as ethyl ether, vinyl isobutyl ether and the like; vinyl monomers such as one or two or more are used.

The styrene-based polymer or styrene-based copolymer may be crosslinked, or may be a resin mixture thereof.

Among the charge control agents used in the developer of the present invention, examples of the negative charge control agent include azo metal complexes represented by the following general formula (I).

[0097]

Embedded image

Next, specific examples of the complex will be shown.

[0099]

Embedded image

[0100]

Embedded image

On the other hand, as the positive charge control agent, there are the following substances.

Modified products of nigrosine and fatty acid metal salts; quaternary ammonium acids such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate;
And onium salts such as phosphonium salts, which are analogs thereof, and their lake pigments, triphenylmethane dyes and these lake pigments. (As the lakening agent, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannin 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 Diorganotin borates; guanidine compounds, imidazole compounds. These can be used alone or in combination of two or more. Among these, a triphenylmethane compound and a quaternary ammonium salt whose counter ion is not halogen are preferably used. The general formula (1)

[0103]

Embedded image [R ₁ : H, CH ₃ R ₂ , R ₃ : a substituted or unsubstituted alkyl group (preferably C _{1 to} C ₄ )] monomer homopolymer: styrene, acrylate, A copolymer with a polymerizable monomer such as methacrylate can be used as a positive charge control agent. In this case, these charge control agents also act as (all or part of) the binder resin.

Further, a compound represented by the following general formula (2) can be used in the constitution of the present invention.

[0105]

Embedded image [Wherein, R ¹ , R ² , R ^3, R ⁴ , R ⁵ , and R ⁶ may be the same or different hydrogen atoms, substituted or unsubstituted alkyl groups, or substituted or unsubstituted aryl groups. Represents a group. R ⁷ , R ⁸ and R ⁹ each represent a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group which may be the same or different from each other. A ^- is an anion such as sulfate ion, nitrate ion, borate ion, phosphate ion, hydroxyl ion, organic sulfate ion, organic sulfonate ion, organic phosphate ion, arbonate ion, organic borate ion, and tetrafluoroborate. Show. ]

An external additive may be added to the developer of the present invention, if necessary.

For example, a charge auxiliary agent, a conductivity-imparting agent, a fluidity-imparting agent, an anti-caking agent, a release agent for fixing a hot roll,
These are inorganic fine particles that function as a lubricant, an abrasive, and the like.

For example, lubricants such as Teflon, zinc stearate and polyvinylidene fluoride are preferable, and polyvinylidene fluoride is particularly preferable. Alternatively, a polishing agent such as cerium oxide, silicon carbide, and strontium titanate, among which strontium titanate is preferable. Alternatively, for example, a fluidity-imparting agent such as titanium oxide or aluminum oxide, particularly a hydrophobic agent is preferable. A small amount of a caking preventing agent, a conductivity imparting agent such as carbon black, zinc oxide, antimony oxide, tin oxide and the like, and white and black fine particles of opposite polarity can also be used as a developing improver.

[0109]

Although the basic configuration and features of the present invention have been described above, the present invention will be specifically described below based on the embodiments. However, this does not limit the embodiment of the present invention at all. Parts in the examples are parts by weight.

Table 1 shows the physical properties of the resin fine particles used in Examples and Comparative Examples, and Table 2 shows the physical properties of the wax.

[0111]

[Table 1]

[0112]

[Table 2]

Example 1 100 parts of styrene-butyl acrylate-monobutyl maleate copolymer (copolymerization ratio 75/20/5, 2 peaks P ₁ / P ₂ = 10,000 / 1,000,000, Mw / Mn = 50) 100 parts of magnetic fine powder (BET 7.5 m ² / g) ² parts of negative charge control agent (monoazo iron complex) 4 parts of hydrocarbon wax A

After premixing the above materials, melt kneading was performed by a twin screw kneading extruder set at 130 ° C.
After cooling, the kneaded product was coarsely pulverized, finely pulverized by a pulverizer using a jet stream, and further classified using an air classifier to obtain toner particles having a weight average particle size of 6.5 μm. 100 parts of the toner particles and 1.0 negatively charged hydrophobic silica fine powder
Was mixed with a silicone oil-treated resin fine particle a0.2 part by a Henschel mixer to obtain a developer.

(Preparation of Developing Sleeve-1) 70 parts of graphite (manufactured by Nippon Graphite Co., major axis diameter 80 μm) 30 parts of carbon black (Conductex 900, manufactured by Columbia Chemical Co., oil absorption 120 cc / 100 g) Resol type phenol resin 100 parts ・ Hardened spherical resol type phenol resin particles 4 parts (Positive chargeability, particle size 4 μm)

The above coating material was added to 76 parts of butyl alcohol, mixed, and then dispersed for 10 hours in a ball mill containing 200 μm diameter balls as media particles. Thereafter, the balls were separated using a 64 mesh screen to obtain a stock solution (solid content: 24% by weight).

60 parts of butyl alcohol was added to the stock solution to prepare a coating solution (solid content: 15% by weight). This coating liquid was formed into a 10 μm film on an Al carrier substrate (aluminum cylinder) having a diameter of 20 mm by a dipping method, and then cured by heating at 150 ° C. for 30 minutes in a hot air drying furnace to prepare a developing sleeve.

The surface roughness (Ra) of the coating layer formed on the aluminum substrate was 2.5 μm.

Next, the prepared developer was evaluated by the following method.

As an electrophotographic apparatus, as shown in FIG. 3, a commercially available LBP-A309GII made by Canon was used after improving the printing speed to 1.5 times. For the cartridge, the Canon EP-B cartridge was modified to a structure that can supply toner, and the developing sleeve was prepared.
Replace with the one obtained in step 1 and print out 15,000 sheets in a high temperature and high humidity environment (30.0 ° C./80% RH) while replenishing the developer. The state of fusion of the toner to the body and the image density were evaluated. Table 3 shows the evaluation results.

(1) Developability Evaluation was made by maintaining the image density at the end of printing out 15,000 sheets on ordinary plain paper for copying machines (75 g / m ² ).
The image density was measured by using a "Macbeth reflection densitometer" (manufactured by Macbeth Co., Ltd.) with respect to a printout image of a white background portion having a document density of 0.00.

○: 1.40 or more Δ: 1.30 or more and less than 1.40 ×: less than 1.30

(2) Fusion of Developing Sleeve After completion of the printout test, the occurrence of scratches on the surface of the developing sleeve, the state of fusion of the toner, and the effect on the printout image were visually evaluated.

◎: Very good (not generated) 良好: Good (almost no occurrence) Δ: Practical (there is fusion but there is little effect on the image) ×: Practical not possible (a lot of fusion and image Causes unevenness)

(3) Fusion of toner on the regulating blade After the printout was completed, scratches on the surface of the regulating blade and the state of fusion of the toner were visually checked.

◎: very good 良好: good (almost no occurrence) △: practicable (there is fusion of the toner, but there is no effect on the image) ×: not possible (image defect)

(4) Photoreceptor Fusing The occurrence of scratches on the photoreceptor drum surface and toner fusing and the effect on printout images were visually evaluated.

：: Good (not generated) Δ: Practical (fused or flawed, but has little effect on image) ×: Impossible (many fused, causing vertical streak-like image defects)

(5) Fixing Property The fixing property was evaluated by applying a load of 50 g / cm ² , rubbing the fixed image with a soft thin paper, and decreasing the image density before and after rubbing (%).

（(Good): less than 10% Δ (acceptable): 10% or more, less than 20% × (impossible): 20% or more

(6) Offset Resistance The offset resistance was evaluated by printing out a sample image having an image area ratio of about 5% and evaluating the degree of stain on the image after 3000 sheets.

：: good Δ: practicable ×: practicable

(7) Blocking test Approximately 20 g of the developer was placed in a 100 cc plastic
After leaving it at 3 ° C. for 3 days, it was visually evaluated.

○: No aggregate was observed. Δ: Aggregates are observed but easily collapse. X: Aggregates can be grasped and do not easily collapse.

In the same manner, the following Examples 2 to 7 and Comparative Example 1
The same evaluation as in Example 1 was performed for the developers shown in Nos. 1 to 4. Table 3 shows the evaluation results.

Example 2 A developer was prepared in the same manner as in Example 1 except that wax B was used instead of wax A, and fine resin particles c were used instead of fine resin particles a.

Example 3 A developer was prepared in the same manner as in Example 1 except that fine resin particles b were used instead of fine resin particles a.

Example 4 A developer was prepared in the same manner as in Example 1 except that wax C was used instead of wax A.

Example 5 A developer was prepared in the same manner as in Example 1 except that wax D was used instead of wax A.

Example 6 A developer was prepared in the same manner as in Example 1 except that wax B was used instead of wax A, and fine resin particles d were used instead of fine resin particles a.

Example 7 A developer was prepared in the same manner as in Example 1 except that wax E was used instead of wax A.

Comparative Example 1 A developer was prepared in the same manner as in Example 1 except that resin fine particles e were used instead of resin fine particles a.

Comparative Example 2 A developer was prepared in the same manner as in Example 1 except that wax F was used instead of wax A and resin fine particles f were used instead of resin fine particles a.

Comparative Example 3 A developer was prepared in the same manner as in Example 1 except that wax G was used instead of wax A, and no fine resin particles were added.

Comparative Example 4 A developer was prepared in the same manner as in Example 1 except that wax H was used instead of wax A and resin fine particles g were used instead of resin fine particles a.

[0146]

[Table 3]

[0147]

According to the present invention, the use of the above-mentioned hydrocarbon wax and fine resin particles provides excellent fixing properties, anti-offset properties, anti-blocking properties and developability. It is possible to provide a developer for developing an electrostatic image, which does not cause the toner to fuse to the member and the electrostatic latent image holding member.

[Brief description of the drawings]

FIG. 1 shows an example of the appearance of resin fine particles used in the present invention.

FIG. 2 is a schematic explanatory diagram of a DSC curve when the temperature of a hydrocarbon wax used in the present invention is raised.

FIG. 3 is a schematic explanatory view of an image forming apparatus used in an embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 developing device 2 developer container 3 latent image carrier 4 transfer means 5 laser light or analog light 6 developing sleeve 7 cleaning blade 8 regulating blade 11 charging means 12 bias applying means 13 developer 14 cleaning means 15 magnetic field generating means 20 heating element 21 Fixing roller 22 Pressure roller

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Shunji Suzuki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-4-146553 (JP, A) JP-A-4 -274444 (JP, A) JP-A-2-134648 (JP, A) JP-A-61-59352 (JP, A) JP-A-61-59455 (JP, A) JP-A-4-204543 (JP, A) JP-A-5-80582 (JP, A) JP-A-4-274442 (JP, A) JP-A-4-284476 (JP, A) JP-A-3-200986 (JP, A) JP-A-7- 56435 (JP, A) JP-A-7-160039 (JP, A) JP-A-7-77830 (JP, A) JP-A-6-118699 (JP, A) JP-A-6-250438 (JP, A) JP-A-7-13417 (JP, A) JP-A-59-67554 (JP, A) JP-A-6-332228 (JP, A) A) JP-A-6-123994 (JP, A) JP-A-7-36210 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/08

Claims (15)

(57) [Claims] 1. A least a binder resin, toner particles containing a hydrocarbon wax and a colorant, a developer for developing an electrostatic image formed by a small resin particles and inorganic fine powder than the particle size of the toner particles The hydrocarbon wax has an on-set temperature in a DSC curve at a temperature rise of 65 to 105 ° C., a peak temperature of 75 to 120 ° C., and the resin fine particles have a viscosity of 50 to 60,000 cSt. Surface treated with oil , Vickers hardness is
5.0 to 30.0 kg / mm ² and an average particle size of 0.
Electrostatic image developer which is a 05~2.0μ m. 2. The resin fine particles have a viscosity of 1200 to 300.
The developer for developing an electrostatic image according to claim 1, wherein the developer is resin fine particles treated with a silicone oil of 00 cSt. 3. The hydrocarbon wax has a number average molecular weight (Mn) of 200 to 2500 and a weight average molecular weight (Mw).
Is 400-5000, and its molecular weight distribution Mw /
The developer for developing an electrostatic image according to claim 1, wherein Mn is 3 or less. 4. The hydrocarbon wax according to the following formula (1), (2) or (3): [Where x represents an average value and is 35 to 150]. ] [In the formula, x represents an average value and is 35 to 150, z represents an average value and is 1 to 5, and R represents hydrogen or a carbon number of 1 to 1.
Indicates 0 alkyl groups. ] [In the formula, y represents an average value and is 35 to 150. The developer for developing an electrostatic image according to any one of claims 1 to 3, wherein the developer is a long-chain hydrocarbon compound represented by the formula: 5. The resin fine particles having a particle size of 0.1 to 1.5 μm.
5. The developer for developing an electrostatic image according to claim 1, wherein m is m. 6. A surface area sphericity (微粒子) of the resin fine particles.
The electrostatic image developer according to any one of claims 1 to 5 but wherein the 0.5 to 0.9 der Rukoto. 7. The method according to claim 1, wherein the inorganic fine powder is a silica fine powder subjected to a hydrophobic treatment with a silicon compound.
7. The developer for developing an electrostatic image according to any one of items 1 to 6. 8. A charging step in which a charging member to which an external voltage is applied is brought into contact with the electrostatic latent image holding member to perform charging, a step of forming an electrostatic latent image on the charged electrostatic latent image holding member,
And an image forming method having a step of developing the electrostatic latent image formed on the electrostatic latent image holding member on a developer carrying member by regulating the developer with a developer regulating member. Is a developer for developing an electrostatic charge image comprising toner particles containing at least a binder resin, a hydrocarbon wax and a colorant, resin fine particles smaller than the particle size of the toner particles, and inorganic fine powder. The onset temperature at the time of temperature rise in the DSC curve of the system wax is in the range of 65 to 105 ° C, the peak temperature is in the range of 75 to 120 ° C, and the resin fine particles are surface-treated with silicone oil having a viscosity of 50 to 60,000 cSt And the Vickers hardness is
5.0 to 30.0 kg / mm ² , with an average particle size of 0.
Image forming method which is a 05~2.0μ m. 9. The developer carrier and the developer regulating member are in contact with each other, and the developer carrier is made of graphite, carbon black or a mixture of graphite and carbon black, and has a number average particle size of 0.03 to 30 μm. And spherical particles of
The image forming method according to claim 8, wherein the image forming method is coated with a coating agent containing a binder resin. 10. The resin fine particles have a viscosity of 1200 to 30.
The image forming method according to claim 8, wherein the resin fine particles are treated with 000 cSt silicone oil. 11. The hydrocarbon wax has a number average molecular weight (Mn) of 200 to 2500 and a weight average molecular weight (Mw).
Is 400-5000, and its molecular weight distribution Mw /
11. Mn is 3 or less, wherein Mn is 3 or less.
The image forming method according to any one of the above. 12. The hydrocarbon wax according to the following formula (1), (2) or (3): [Where x represents an average value and is 35 to 150]. ] [In the formula, x represents an average value and is 35 to 150, z represents an average value and is 1 to 5, and R represents hydrogen or a carbon number of 1 to 1.
Indicates 0 alkyl groups. ] [In the formula, y represents an average value and is 35 to 150. The image forming method according to any one of claims 8 to 11, wherein the compound is a long-chain hydrocarbon compound represented by the formula: 13. The resin fine particles having a particle size of 0.1 to 1.5.
The image forming method according to claim 8, wherein the thickness is μm. 14. The image forming method according to any one of claims 8 to 13 surface shape sphericity of the resin particle ([psi) is characterized 0.5-0.9 der Rukoto. 15. The image forming method according to claim 8, wherein the inorganic fine powder is a silica fine powder subjected to a hydrophobic treatment with a silicon compound.