JP3880392B2 - Image forming method - Google Patents

Description

【０１４１】
【発明の効果】
以上説明したように、特に低温低湿環境下で、トナー規制部材として弾性ブレードを用いた現像装置によって、トナーの現像量を低く抑えた低印字率現像動作を多数回繰り返した後、フィルム加熱定着方式で定着しても優れた定着性が得られる画像形成が可能である。
【図面の簡単な説明】
【図１】フィルム定着器の一例の概略図である。
【図２】フィルム定着器の一例の概略図である。
【符号の説明】
２ 加圧ローラ
１２ セラミックヒータ
１３ 定着フィルム
Ｎ 定着ニップ部
Ｐ 記録材
ｔ 未定着トナー[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a toner used in a recording method using an electrophotographic method, an electrostatic recording method, a toner jet method recording method, and the like, and an image forming method. More specifically, the present invention relates to an image forming method used for a copying machine, a printer, and a fax machine in which a toner image is formed on an electrostatic latent image carrier in advance and then transferred onto a transfer material and then fixed to form an image.
[0002]
[Prior art]
Conventionally, many methods are known as electrophotographic methods. In general, a photoconductive substance is used to form an electric latent image on the electrostatic latent image carrier by various means, and then the electrostatic latent image is developed with toner to form a visible image. After the toner image is transferred to a transfer material such as paper, the toner image is fixed on the transfer material by heat, pressure or the like to obtain a copy.
[0003]
In recent years, devices using electrophotography have been applied to devices such as printers and fax machines in addition to conventional copying machines. In particular, printers and fax machines are required to be smaller and save energy.
[0004]
On the other hand, as a developing method, a one-component developing method is often used. In the one-component development method, a one-component developer is used, and the toner particles are charged by the friction between the toner regulating member and the toner particles and the friction between the toner carrier and the toner particles. In this method, the latent image carrier is transported to a development area facing the latent image carrier, and the electrostatic latent image on the latent image carrier is developed to be visualized as a toner image.
[0005]
The one-component development method is roughly divided into a magnetic one-component development method using a magnetic toner containing a magnetic substance in the toner and a non-magnetic one-component development method not using a magnetic substance. An elastic blade is often used as the toner regulating member. This is because the toner is easily coated on the toner carrier in a thin layer and the toner is easily triboelectrically charged.
[0006]
Furthermore, a film heating method is often used as a fixing method for downsizing and energy saving of the apparatus. The film heating method has a smaller heat capacity of the heating device itself than the conventional heat roller heating method, which not only saves power, but also shortens the wait time and enables quick start. Can stop energization of the heating device, and further power saving is possible.
[0007]
On the other hand, the toner used in the one-component development method is required to have excellent fluidity for increasing the contact frequency with the member. To achieve this, it is known that various fine particles are added to the toner. It has been.
[0008]
As such fine particles, inorganic fine particles such as metal oxides are generally used, and among them, silica is widely used. The reason for this is that a very small primary particle size can be obtained at low cost, and excellent fluidity can be achieved by adding it to the toner, and the amount of charge is high and it is used regardless of the chargeability of the toner base. It is because it is possible.
[0009]
Since silica itself is a hydrophilic material, the toner to which it is added is easily affected by the humidity of the atmosphere, and the fluidity and chargeability are not stable. Therefore, in order to improve this point, the silica surface is generally used after being hydrophobized with silicone oil, silicone varnish, silane coupling agent, silylating agent or the like.
[0010]
However, as a result of examination by the present inventors, the toner development amount using an elastic blade as a toner regulating member was suppressed by using a toner added with hydrophobized silica, particularly in a low temperature and low humidity environment. When the low printing rate developing operation was repeated many times, it was confirmed that hydrophobic silica was buried in the toner surface due to the stress received from the elastic blade. Further, it has been found that when the toner is fixed by a film heat fixing method, the fixing property is deteriorated.
[0011]
[Problems to be solved by the invention]
An object of the present invention is to provide an image forming method that solves the above problems.
[0012]
That is, the object of the present invention is to repeat a low printing rate developing operation with a low toner development amount many times by a developing device using an elastic blade as a toner regulating member, particularly in a low temperature and low humidity environment, and then heating the film. It is an object of the present invention to provide an image forming method capable of obtaining excellent fixability even when fixing by a fixing method.
[0013]
[Means for Solving the Problems]
The above object is achieved by the present invention described below.
[0014]
That is, a fixing member and a pressure member that forms a fixing nip portion between the fixing film and a recording material carrying unfixed toner on the surface are nipped and conveyed to the fixing nip portion. In an image forming method for fixing by heating,
The toner has a hydrophobicity of 90% or more on colored particles containing at least a colorant and a binder resin, and a surface silanol amount A (pieces / piece). ( g · 10 ^-18 ) ) Further, the present invention relates to an image forming method, wherein hydrophobic silica having a carbon amount B (mass%) of A / B = 3 to 30 and B = 4 to 10 is added.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
As a result of intensive studies by the inventor, a recording material having a fixing film and a pressure member that forms a fixing nip portion between the fixing film and an unfixed toner carried on the surface, In the image forming method in which fixing is performed by heating while being held and conveyed in the fixing nip portion, the hydrophobicity of the colored particles containing at least the colorant and the binder resin is 90% or more, and the surface silanol amount A (pieces / piece). ( g · 10 ^-18 ) ) The present inventors have found that the above problem can be solved by using a toner to which hydrophobic silica having a carbon amount B (mass%) of A / B = 3 to 30 and B = 4 to 10 is added.
[0016]
Details will be described below.
[0017]
As described above, especially in a low-temperature and low-humidity environment, a toner with hydrophobic silica added is used, and a developing device using an elastic blade as a toner regulating member, a low printing rate developing operation with a low toner development amount. Was repeated many times, it was confirmed that the hydrophobic silica was buried in the toner surface due to the stress received from the elastic blade, and further, it was found that the fixing property deteriorates when the toner is fixed by the film heating fixing method.
[0018]
When the toner was examined in more detail, hydrophobic silica was aggregated in a scaly manner and embedded in the toner surface. The scale-like hydrophobic silica aggregates were layered to cover the toner surface, and the toner was in a state of being densely coated with hydrophobic silica.
[0019]
When a fixing test was performed using this toner while changing the set temperature with a film fixing device, the toner had deteriorated compared with the fixing property of the toner before the low printing rate developing operation was repeated many times.
[0020]
On the other hand, when a similar fixing test was performed with a normal heat roll fixing device, no deterioration in fixing property was observed.
[0021]
In order to elucidate the difference in fixability due to the difference in the fixing device, the cross section of each fixed image of the toner covered with the hydrophobic silica aggregated in the form of scales on the film fixing device and the heat roll fixing device is observed with a TEM. As a result, in the heat roll fixing device, the individual toner melts to such an extent that it does not retain its original shape, and the scaly silica aggregates covering the toner surface are also encased in the toner binder resin, and the adjacent toners merge. In contrast, in the film fixing device, some of the individual toners remained as agglomerates, and a wall of hydrophobic silica aggregates was observed between adjacent toners.
[0022]
From this observation result, the present inventor has inferred the reason why the fixability of the toner covered with the flaky hydrophobic silica aggregate deteriorates in the film fixing device as follows.
[0023]
As mentioned above, since the film heating method uses a film with a small heat capacity, there are many advantages such as power saving and quick start compared to the conventional heat roller heating method, but the durability of the film and the film There is a demerit that the pressure of the fixing nip portion that applies heat to the toner on the recording material cannot be as large as that of the heat roller because of the occurrence of wrinkles, kinks and the strength of the heating element.
[0024]
When fixing the toner covered with scaly hydrophobic silica aggregates with a hot roll fixing device, the pressure at the fixing nip is high, so the toner is heated in a crushed state and is fixed well. On the other hand, in the film fixing device, scaly hydrophobic silica aggregates exist as walls, so even if individual toners melt, there are portions where the adjacent toners are insufficiently joined together, so the fixability deteriorates. It seems to be.
[0025]
Therefore, the relationship between the hydrophobicity of silica, the embedded state of hydrophobic silica in the toner surface in a developing device using an elastic blade, and the fixing property in a film fixing device was examined. / ( g · 10 ^-18 ) ) It was found that the fixability in a film fixing device can be improved by using hydrophobic silica having a carbon amount B (mass%) of A / B = 3 to 30 and B = 4 to 10. Here, the surface silanol amount A is caused by the amount of residual silanol on the silica surface after the hydrophobic treatment, and the carbon amount B is caused by the amount of the hydrophobic treatment agent.
[0026]
In a developing device that uses an elastic blade as a toner regulating member, it is difficult to physically avoid the embedding of hydrophobic silica on the toner surface that is particularly likely to occur when a low printing rate developing operation is repeated many times. However, surface silanol content A (pieces / ( g · 10 ^-18 ) ) In the case of hydrophobic silica having a carbon content B (mass%) in the above range, the toner surface is not covered with the scaly layers and is buried in the toner surface with almost the primary particle size. It was. That is, it is possible to prevent the silica from growing into scaly aggregates on the toner surface due to the shear stress from the elastic blade.
[0027]
Further, the amount of surface silanol A (pieces / ( g · 10 ^-18 ) ) When the cross section of the fixed image on the film fixing device of the toner in which the hydrophobic silica having the carbon content B (mass%) in the above range is embedded in the surface with almost the primary particle diameter is observed with a TEM, it is dissolved. The toner encapsulated the hydrophobic silica present in the primary particle size, and the toners in contact with each other were united.
[0028]
In addition, the measurement of the amount of surface silanols in this invention used the lithium aluminum hydride method. Moreover, the carbon amount was measured using an element analyzer EA-1108 (manufactured by Carlo Erba).
[0029]
The carbon amount B is preferably 4 to 10, and more preferably 5 to 8. When the carbon content B is less than 4, it is not preferable because the fixing film is damaged by silica. On the other hand, when the carbon content B exceeds 10, it is not preferable because it is easy to form the above-mentioned scaly aggregate and the fixability deteriorates.
[0030]
The ratio of the surface silanol amount A to the carbon amount B, A / B, is preferably 3 to 30, and more preferably 10 to 25. When A / B is less than 3, the amount of surface silanol that becomes a charge leak site is small, so that charge-up occurs in a low-temperature and low-humidity environment, so that developability deteriorates and image density decreases. On the other hand, when A / B exceeds 30, it is not preferable because aggregates are easily formed during the hydrophobization treatment and grow in a scale shape.
[0031]
In the present invention, the surface silanol amount A (pieces / ( g · 10 ^-18 ) ) The hydrophobizing agents used to bring the carbon content B (% by mass) into the above range are hexamethyldisilazane, trimethylchlorosilane, dimethyldichlorosilane, isobutyltrimethoxysilane, dimethyl silicone oil, methylphenyl Silicone oil, diphenyl silicone oil, methyl hydrogen silicone oil and the like are preferably used.
[0032]
In the present invention, the hydrophobic rate of hydrophobic silica is preferably 90% or more. When the hydrophobicity is less than 90%, silica is adsorbed to moisture in the atmosphere environment of the toner, particularly in a high humidity environment, and the triboelectric charge necessary for development is reduced, and fogging is not preferable.
[0033]
The hydrophobicity of silica was measured by the following method. Take 1 g of silica in a 200 ml separatory funnel and add 100 ml of ion-exchanged water. A separatory funnel is set in a turbula shaker T2C and dispersed at 90 rpm for 10 minutes. Thereafter, the mixture is allowed to stand for 10 minutes, and then 20 to 30 ml is extracted, and then taken into 10 mm cells. The turbidity of the water layer is measured with a spectrophotometer UV-210 (Shimadzu Corporation) using ion-exchanged water as a blank. The reading at a wavelength of 500 nm is defined as the hydrophobicity.
[0034]
In order to make the hydrophobicity of silica 90% or more, it is preferable to hydrophobize silica with silicone oil, silicone varnish, silane coupling agent, silylating agent, and the like.
[0035]
The treatment amount of the hydrophobic treatment agent is preferably 20 to 50% by mass of the treatment agent as the hydrophobic treatment silica.
As a method for the hydrophobization treatment, a vapor phase method or a solvent method is used, and a vapor phase method is preferable.
[0036]
The hydrophobic silica used in the present invention preferably has a primary average particle size of 25 nm or less. By setting the primary average particle size to 25 nm or less, the fluidity of the toner is improved, and the toner on the recording material before fixing is more densely packed, so that heat is efficiently transmitted and good fixability is obtained. .
[0037]
The addition amount of the hydrophobic silica of the present invention is preferably 0.2 to 3.5% by mass as the content in the toner, more preferably 0.3 to 2.5% by mass.
[0038]
Further, the toner of the present invention preferably has an average circularity of 0.950 to 0.990 by a flow type particle image analyzer. By setting the average circularity to 0.950 to 0.990, the toner on the recording material before fixing is more densely packed, so that heat is efficiently transmitted and good fixability is obtained.
[0039]
Furthermore, it is preferable that the standard deviation of circularity is 0.035 or less. The toner in the vicinity of the average circularity tends to be selectively consumed by the development, and the proportion of the toner near the irregular shape having a small average circularity increases in the developing device after the development operation is repeated many times. There is a tendency. When the standard deviation of the circularity is 0.035 or less, since the distribution of the circularity of the toner is sharp, there is an effect of suppressing an increase in the ratio of the toner having a small average circularity, which is preferable.
[0040]
In the present invention, the average circularity and the standard deviation of the circularity were measured with a flow type particle image analyzer FPIA-1000 manufactured by Toa Medical Electronics Co., Ltd.
[0041]
The measurement removes fine debris through a filter and results in 10 ^-3 cm ^Three A few drops of nonionic surfactant (Contaminone N, manufactured by Wako Pure Chemical Industries, Ltd.) were added to water having a measurement range (for example, an equivalent circle diameter of 0.60 μm or more and less than 159.21 μm) in water of 20 or less. Using a sample dispersion prepared by adding 5 mg of toner to 10 ml of an aqueous solution and performing dispersion treatment with UH-50 manufactured by STM as an ultrasonic disperser, it has an equivalent circle diameter of 0.60 μm or more and less than 159.21 μm. Measure the particle size distribution of the particles.
[0042]
The outline of the measurement is as follows.
[0043]
The sample dispersion is allowed to pass through a flow path (expanded along the flow direction) of a flat and flat transparent flow cell (thickness: about 200 μm). The strobe and the CCD camera are mounted so as to be opposite to each other with respect to the flow cell so as to form an optical path that passes across the thickness of the flow cell. While the sample dispersion is flowing, strobe light is irradiated at 1/30 second intervals to obtain an image of the particles flowing through the flow cell, so that each particle is a two-dimensional having a certain range parallel to the flow cell. Taken as an image. From the area of the two-dimensional image of each particle, the diameter of a circle having the same area is calculated as the equivalent circle diameter.
[0044]
In about 1 minute, the equivalent circle diameter of 1200 or more particles can be measured, and the number based on the equivalent circle diameter distribution and the ratio (number%) of particles having a prescribed equivalent circle diameter can be measured.
[0045]
The average circularity is obtained by calculating the circularity of particles measured using the flow type particle image analyzer FPIA-1000 from the following equation, and dividing the total circularity of all particles measured by the total number of particles. Defined as average circularity.
[0046]
Circularity = (perimeter of a circle with the same projected area as the particle image) / (perimeter of the projected image of the particle)
[0047]
The average circularity in the present invention is an index of the degree of unevenness of toner particles, and indicates 1.000 when the toner is a perfect sphere, and the average circularity becomes smaller as the toner shape becomes more complicated.
[0048]
The toner satisfying the circularity of the present invention preferably has a weight average particle diameter in the range of 4 to 10 μm.
[0049]
The weight average particle diameter of the toner was measured using Coulter Multisizer II (manufactured by Coulter). An interface for outputting number distribution and volume distribution (manufactured by Nikka) and a PC9801 personal computer (manufactured by NEC) are connected to Coulter Multisizer II, and a 1% NaCl aqueous solution is prepared using first-grade sodium chloride as the electrolyte. For example, ISOTON R-II (manufactured by Coulter Scientific Japan) can be used. As a measuring method, 0.1 to 5 ml of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added. The electrolyte in which the sample is suspended is dispersed for about 1 to 3 minutes with an ultrasonic disperser, and the volume and number of toners of 2 μm or more are measured using the Coulter Multisizer with a 100 μm aperture as the aperture. Distribution and number distribution were calculated. Then, the weight average particle diameter based on the weight based on the volume distribution according to the present invention (representing the representative value of each channel as the representative value for each channel) was obtained.
[0050]
The method for producing the toner of the present invention is not particularly limited, but in order to obtain an average circularity of 0.950 to 0.990, it is produced by a suspension polymerization method, a mechanical pulverization method, a spheronization treatment, or the like. The suspension polymerization method is particularly preferable.
[0051]
Hereinafter, a method for producing the toner of the present invention in the suspension polymerization method will be described.
[0052]
First, a low softening point substance, a polar resin, a colorant, a charge control agent, a polymerization initiator, and other additives were added to the polymerizable monomer and dissolved or dispersed uniformly by a homogenizer, an ultrasonic disperser, or the like. The monomer system is dispersed in an aqueous phase containing a dispersion stabilizer by a usual stirrer, homogenizer, homomixer or the like. At this time, granulation is preferably performed while adjusting the stirring speed and time so that the monomer droplets have a desired developer particle size. Thereafter, stirring may be performed to such an extent that the particle state is maintained and the settling of the particles is prevented by the action of the dispersion stabilizer. The polymerization temperature is preferably set to 40 ° C. or higher, generally 50 ° C. to 90 ° C. In addition, the temperature may be raised in the latter half of the polymerization reaction, and further, in order to remove unreacted polymerizable monomers and by-products that cause odors when fixing the developer, the latter half of the reaction or at the end of the reaction. A part of the aqueous medium may be distilled off. After completion of the reaction, the produced developer particles are washed, collected by filtration and dried. In the suspension polymerization method, it is usually preferable to use 300 parts by mass to 3000 parts by mass of water as a dispersion medium with respect to 100 parts by mass of the monomer system.
[0053]
Toner particle size distribution control and particle size control can be done by adjusting the pH of the system during granulation, changing the type and addition amount of a sparingly water-soluble inorganic salt and protective colloid, mechanical equipment conditions, For example, it can be achieved by controlling the stirring conditions such as the peripheral speed of the rotor, the number of passes, the shape of the stirring blade, the shape of the container or the solid content in the aqueous solution, and the like.
[0054]
Examples of the polymerizable monomer used in the present invention include styrene monomers such as styrene, o- (m-, p-) methylstyrene, m- (p-) ethylenestyrene; methyl (meth) acrylate, Propyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, 2-ethylhexyl (meth) acrylate (Meth) acrylate monomers such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate; monomers such as butadiene, isoprene, cyclohexane, (meth) acrylonitrile, and acrylamide Preferably used.
[0055]
Moreover, as a polar resin added at the time of superposition | polymerization, the copolymer of a styrene (meth) acrylic acid, a maleic acid copolymer, a polyester resin, and an epoxy resin are used preferably.
[0056]
Further, as the low softening point substance used in the present invention, paraffin wax, polyolefin wax, Fischer-Tropsch wax, amide wax, higher fatty acid, ester wax and derivatives thereof, or graft / block compounds thereof are preferably used. It is done.
[0057]
As the charge control agent used in the present invention, known ones can be used, but a charge control agent having no polymerization inhibition and no solubilized product in an aqueous system is particularly preferable. Specific examples of negative compounds include salicylic acid, naphthoic acid, dicarboxylic acid, metal compounds of their derivatives, polymer compounds having sulfonic acid in the side chain, boron compounds, urea compounds, silicon compounds, calixarene, etc. As the positive system, a quaternary ammonium salt, a polymer compound having the quaternary ammonium salt in the side chain, a guanidine compound, an imidazole compound, or the like is preferably used. The charge control agent is preferably 0.2 to 10 parts by mass with respect to 100 parts by mass of the polymerizable monomer.
[0058]
Examples of the polymerization initiator used in the present invention include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1). -Carbonitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azo-based polymerization initiators such as azobisisobutylnitrile; benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroxy peroxide, A peroxide polymerization initiator such as 2,4-dichlorobenzoyl peroxide or lauroyl peroxide is used.
[0059]
The addition amount of the polymerization initiator varies depending on the desired degree of polymerization, but generally 0.5 to 20% by mass is added to the monomer. The kind of the polymerization initiator is slightly different depending on the polymerization method, but may be used alone or mixed with reference to the 10-hour half-life temperature.
[0060]
Examples of the dispersant used when using suspension polymerization include inorganic calcium oxides such as tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, and hydroxide. Examples thereof include magnesium, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina, magnetic substance, and ferrite. As the organic compound, for example, polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, starch and the like are used dispersed in an aqueous phase.
[0061]
These dispersants are preferably used in an amount of 0.2 to 2.0 parts by mass with respect to 100 parts by mass of the polymerizable monomer.
[0062]
These commercially available dispersants may be used as they are, but in order to obtain dispersed particles having a fine and uniform particle size, they can also be obtained by producing the inorganic compound in a dispersion medium under high-speed stirring. . For example, in the case of calcium phosphate, a dispersant preferable for the suspension polymerization method can be obtained by mixing an aqueous sodium phosphate solution and an aqueous calcium chloride solution under high-speed stirring.
[0063]
Moreover, you may use 0.001-0.1 mass part surfactant together for refinement | miniaturization of these dispersing agents. Specifically, commercially available nonionic, anionic and cationic surfactants can be used, such as sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, Calcium oleate is preferably used.
[0064]
Next, a toner manufacturing method in the pulverization method will be described.
[0065]
Examples of the binder resin used in the pulverized toner of the present invention include polystyrene, poly-α-methylstyrene, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, and styrene-vinyl acetate. Copolymers, styrene-acrylic acid ester copolymers, styrene-methacrylic acid acrylic copolymers, vinyl chloride resins, polyester resins, epoxy resins, phenol resins, polyurethane resins, etc. can be used alone or in combination. -Acrylic, styrene-methacrylic copolymer resin and polyester resin are preferred.
[0066]
Further, when the pulverized toner of the present invention is controlled to be positively charged, a modified product of a fatty acid metal salt or the like; 4 such as tributylbenzidyl ammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, etc. Onium salts such as quaternary ammonium salts and their analogs such as phosphonium salts; amine and polyamine compounds; metal salts of higher fatty acids; acetylacetone metal complexes; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide Diorgano tin borate such as dibutyl tin borate, dioctyl tin borate, dicyclohexyl tin borate and the like are added. Moreover, when controlling to negative chargeability, an organometallic complex and a chelate compound are effective, and a monoazo metal complex, an acetylacetone metal complex, an aromatic hydroxycarboxylic acid, and an aromatic dicarboxylic acid metal complex can be used. The amount used is 0.1 to 15 parts by mass, preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the binder resin.
[0067]
A release agent can be added to the pulverized toner of the present invention as necessary. For example, aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, paraffin wax, and Fischer-Tropsch wax or oxides thereof; waxes mainly composed of aliphatic esters such as carnauba wax and montanic acid ester wax; And those obtained by deoxidizing some or all of them. In addition, saturated linear fatty acids such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids such as brassic acid, eleostearic acid, and valinalic acid; stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauvir alcohol, and seryl alcohol , Saturated alcohols such as melyl alcohol; polyhydric alcohols such as sorbitol; fatty acid amides such as linoleic acid amide; saturated fatty acid bisamides such as methylene bis stearic acid amide; unsaturated fatty acid amides such as ethylene bisoleic acid amide Aromatic bisamides such as N, N′-distearylisophthalic acid amide; fatty acid metal salts such as zinc stearate; waxes grafted to a hydrocarbon hydrocarbon wax using a vinyl monomer such as styrene; Be A partially esterified product of a fatty acid such as henic acid monoglyceride and a polyhydric alcohol; a methyl esterified product having a hydroxyl group obtained by hydrogenation of vegetable oil or the like can also be used. The addition amount is 0.1 to 20 parts by mass, preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the binder resin.
[0068]
Next, these binder resins, mold release agents, charge control agents, colorants, etc. are sufficiently mixed by a mixer such as a Henschel mixer or a ball mill, and then a heat kneader such as a heating roll, a kneader or an extruder is used. Dissolve or dissolve the charge control agent and colorant while melting and kneading the resins together. After cooling and solidifying, mechanically pulverize to the desired particle size, and further sharpen the particle size distribution by classification. To do. Alternatively, after cooling and solidification, a finely pulverized product obtained by colliding with a target under a jet stream is spheroidized by heat or mechanical impact force.
[0069]
Furthermore, in the present invention, the following inorganic powder can be further added to improve developability and durability. Metal oxides such as magnesium, zinc, aluminum, titanium, cerium, cobalt, iron, zirconium, chromium, manganese, strontium, tin, antimony; complex metal oxides such as calcium titanate, magnesium titanate, strontium titanate; sulfuric acid Metal salts such as barium, calcium carbonate, magnesium carbonate, and aluminum carbonate; clay minerals such as kaolin; phosphate compounds such as apatite; silicon compounds such as silicon carbide and silicon nitride; and carbon powders such as carbon black and graphite.
[0070]
For the same purpose, the following organic particles and composite particles may be added. Resin particles such as polyamide resin particles, silicone resin particles, silicone rubber particles, urethane particles, melamine-formaldehyde particles, acrylic particles; rubbers, waxes, fatty acid compounds, resins, etc. and metals, metal oxides, salts, carbon black, etc. Composite particles composed of inorganic particles; Fluorine resins such as polyfluorinated ethylene and polyvinylidene fluoride; Fluorine compounds such as carbon fluoride; Fatty acid metal salts such as zinc stearate; Fatty acid derivatives such as fatty acids and fatty acid esters; Molybdenum sulfide And amino acids and amino acid derivatives.
[0071]
Next, the image forming method of the present invention will be described.
[0072]
The fixing device used in the image forming method of the present invention has a fixing film and a pressure member for forming a fixing nip portion between the fixing film, and a recording material on which unfixed toner is carried on the surface Is fixed by heating while being nipped and conveyed to the fixing nip portion.
[0073]
FIG. 1 is a schematic view of an example of a film heating type fixing device. A fixing nip portion N is formed by sandwiching a heat resistant film 13 between a ceramic heater 12 as a heating body fixedly supported by the heater holder 11 and a pressure roller 2 as a pressure member. The recording material P carrying the unfixed toner t is introduced between the heat resistant film 13 and the pressure roller 2 with the image surface side being the film side, and the fixing nip portion N is formed together with the heat resistant film 13. By nipping and conveying, the heat of the ceramic heater 12 is applied to the recording material P via the heat-resistant film 13 and heated to heat-fix the image.
[0074]
The ceramic heater 12 includes a heater substrate 12a made of alumina or the like, an energized heating element pattern 12b such as Ag / Pd (silver palladium) formed on the surface side of the substrate, and a heater substrate 12a on which the energized heating element pattern 12b is formed. A line having a low heat capacity is composed of a surface protection layer 12c such as a glass layer formed by covering the surface, a temperature detection element 12d such as a thermistor provided on the back side of the heater substrate 12a, a safety element 12e such as a temperature fuse, and the like. When the energization heating element pattern 12b is energized, the temperature is quickly raised, and the temperature is adjusted to a predetermined temperature by an energization control circuit including the temperature detection element 12d.
[0075]
The heat resistant film 13 is a single layer or composite layer film material such as polyimide, polyamide, and PTFE having a thickness of 100 μm or less, preferably 20 to 40 μm, and having heat resistance, releasability, strength, and durability.
[0076]
Further, FIG. 2 is a schematic view of another example of a film heating type fixing device.
[0077]
Reference numeral 21 denotes an exciting coil unit which is a magnetic field generating means. Reference numeral 22 denotes an endless belt-like film (magnetic film) of electromagnetic induction heat generation, and 23 and 24 denote a driving roller and a tension roller for the film 22. The magnetic film 22 is a film material in which a silicone rubber layer is coated on the outer peripheral surface of an endless belt-like film base layer made of a nickel material which is a magnetic material.
[0078]
A pressure roller 25 is formed by forming a silicone rubber layer on a magnetic metal core. The pressure roller 25 is bearing-supported between pressure support plates 26 that are free to swing around a support shaft 26a on the front side and the back side of the device side plate. By pressing and energizing 26 with a pressure spring 27, the pressure roller 25 is pressed against the lower surface of the exciting coil unit 21 with a predetermined pressing force with the magnetic film 22 interposed therebetween, thereby forming a fixing nip portion N. I'm allowed.
[0079]
An alternating magnetic field generated by a high frequency current flowing from an excitation circuit (not shown) connected to the excitation coil unit mainly acts on the magnetic film 22 at the nip portion N, and the magnetic film 22 generates heat by electromagnetic induction. To do. In this state, the recording material P carrying the unfixed toner t is introduced between the magnetic film 22 in the nip portion N and the pressure roller 25 with the image surface side of the magnetic film 22 side. By nipping and conveying the nip portion N together with the film 22, the toner image on the surface of the recording material P is thermally fixed by the heat of the magnetic film 22 and the pressure roller 25 that generate electromagnetic induction heat.
[0080]
In any film fixing device, the weight of the fixing nip portion is 2.94 to 11.8 N / weight as the weight per unit length in the fixing device longitudinal direction because of the durability of the film, the wrinkle of the film, and the twist. cm (0.3 to 1.2 Kg / cm) is preferable.
[0081]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. “Parts” means all parts by mass.
[0082]
<Example 1>
In a 2-liter four-necked flask equipped with a high-speed stirring device CLEARMIX (M-Technics), 630 parts of ion-exchanged water and 0.1 mol / liter of Na _Three PO _Four 485 parts of an aqueous solution was added, and the number of rotations of CLEARMIX was adjusted to 14000 rpm and heated to 63 ° C. Here, 1.0 mol / liter CaCl ₂ Gradually add 65 parts of an aqueous solution, and then add 10% hydrochloric acid dropwise to add a minute water-insoluble dispersant Ca _Three (PO _Four ) ₂ An aqueous medium having a pH of 5.8 was prepared.
[0083]
On the other hand, the dispersoid system is
・ 155 parts of styrene monomer
・ 45 parts of butyl acrylate monomer
・ 20 parts of carbon black
・ 0.9 parts of salicylic acid metal compound
Was dispersed using an attritor for 5 hours, and then the following components were added to the above mixture and further dispersed for 2 hours to prepare a dispersoid system.
-15 parts of saturated polyester (acid value 9.3 mg KOH / g, peak molecular weight 11000)
・ Ester wax 20 parts
[0084]
Next, after adding 5 parts of a polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile) to the dispersoid system, the dispersion was put into the dispersion medium, and the nitrogen temperature was 67 ° C. Granulated at 17000 rpm for 15 minutes. Thereafter, the stirrer was replaced with a propeller stirrer, and polymerization was performed for 5 hours while maintaining at 70 ° C. while stirring at 50 rpm, and the internal temperature was raised to 77 ° C. and polymerization was performed for 5 hours. After the polymerization was completed, the slurry was cooled and diluted hydrochloric acid was added to remove the dispersant. Further, it was washed with water, dried and classified to obtain colored particles.
[0085]
On the other hand, 100 parts of untreated silica having a primary particle size of about 7 nm is placed in a closed high-speed stirrer and stirred while purging with nitrogen. A treatment agent obtained by diluting 40 parts of dimethyl silicone oil 5.5 times with THF is sprayed into a stirrer. After spraying the entire amount of the treatment agent, the temperature in the stirrer was raised to 365 ° C. while stirring and stirred for 3 hours. The temperature in the stirrer was returned to room temperature while stirring and then crushed with a pin mill, and the hydrophobicity was 99.3%, A / B = 19.5, B = 7.0, and the primary particle size was about 7 nm. Of hydrophobic silica was obtained.
[0086]
A toner was obtained by adding 1.5 parts of the hydrophobic silica to 100 parts of the colored particles by a Henschel mixer FM10B.
[0087]
The toner had a weight average diameter of 6.6 μm, an average circularity by a flow type particle image analyzer of 0.986, and a standard deviation of the circularity of 0.015.
[0088]
The toner was subjected to a print test using a commercially available color laser printer LBP2160 (manufactured by Canon Inc.) at a printing ratio of 2%. The toner regulating member of the printer is an elastic blade, and the test was performed by continuously printing 5000 sheets in a 15 ° C./5% RH environment. Remove the printer fixing device at the 10th and 5000th sheets during continuous printing, and the toner coat amount on paper 0.5 mg / cm ² The solid image was sampled in an unfixed state.
[0089]
Further, in the film fixing device shown in FIG. 2, the film speed = 90 mm / s, the fixing nip portion load = 7.8 N / cm (0.8 Kg / cm), and the fixing temperature = 175 ° C. Fixed the ringtone image.
[0090]
<Example 2>
Hydrophobic silica having a hydrophobicity of 91.2%, A / B = 20.5, B = 4.7, and primary particle size of about 7 nm, except that the amount of dimethyl silicone oil was 25 parts. Got.
[0091]
To 100 parts of the colored particles used in Example 1, 1.5 parts of the hydrophobic silica was externally added with a Henschel mixer FM10B to obtain a toner.
[0092]
The toner had a weight average diameter of 6.6 μm, an average circularity by a flow type particle image analyzer of 0.986, and a standard deviation of the circularity of 0.015.
[0093]
The toner was evaluated in the same manner as in Example 1.
[0094]
<Example 3>
Except that the amount of dimethyl silicone oil was 50 parts, the dilution solvent was hexane, and the dilution ratio was 6 times, the hydrophobicity was 99.4%, A / B = 12.2, B = 8.5, hydrophobic silica with a primary particle size of about 7 nm was obtained.
[0095]
To 100 parts of the colored particles used in Example 1, 1.5 parts of the hydrophobic silica was externally added with a Henschel mixer FM10B to obtain a toner.
[0096]
The toner had a weight average diameter of 6.6 μm, an average circularity by a flow type particle image analyzer of 0.986, and a standard deviation of the circularity of 0.015.
[0097]
The toner was evaluated in the same manner as in Example 1.
[0098]
<Example 4>
A non-treated silica having a primary particle size of 14 nm was used in the same manner as in Example 1 except that the amount of dimethyl silicone oil was 30 parts and the treatment temperature was 290 ° C. = 5.8, B = 4.8, hydrophobic silica having a primary particle size of about 14 nm was obtained.
[0099]
To 100 parts of the colored particles used in Example 1, 1.5 parts of the hydrophobic silica was externally added with a Henschel mixer FM10B to obtain a toner.
[0100]
The toner had a weight average diameter of 6.6 μm, an average circularity by a flow type particle image analyzer of 0.986, and a standard deviation of the circularity of 0.015.
[0101]
The toner was evaluated in the same manner as in Example 1.
[0102]
<Example 5>
The hydrophobicity was 94.8%, A / B = 25.2, B except that the amount of dimethyl silicone oil was 28 parts, the treatment temperature was 250 ° C. and the treatment time was 1.5 hours. = 5.8, hydrophobic silica having a primary particle size of about 14 nm was obtained.
[0103]
To 100 parts of the colored particles used in Example 1, 1.5 parts of the hydrophobic silica was externally added with a Henschel mixer FM10B to obtain a toner.
[0104]
The toner had a weight average diameter of 6.6 μm, an average circularity by a flow type particle image analyzer of 0.986, and a standard deviation of the circularity of 0.015.
[0105]
The toner was evaluated in the same manner as in Example 1.
[0106]
<Example 6>
Hydrophobic rate was 98.5%, A / B = 7.9, B except that untreated silica having a primary particle size of 35 nm was used and the amount of dimethyl silicone oil was 15 parts. = 6.2, hydrophobic silica having a primary particle size of about 35 nm was obtained.
[0107]
To 100 parts of the colored particles used in Example 1, 1.2 parts of the hydrophobic silica was externally added with a Henschel mixer FM10B to obtain a toner.
[0108]
The toner had a weight average diameter of 6.6 μm, an average circularity by a flow type particle image analyzer of 0.986, and a standard deviation of the circularity of 0.015.
[0109]
The toner was evaluated in the same manner as in Example 1.
[0110]
<Example 7>
・ Styrene-acrylic resin 100 parts
(Styrene-butyl acrylate copolymer ratio = 70: 30)
・ 8 parts of carbon black
・ 0.7 parts of salicylic acid metal compound
・ 2 parts of paraffin wax
The above was mixed using a Henschel mixer, melt-kneaded with a biaxial extrusion kneader, coarsely pulverized with a hammer mill, finely pulverized with a jet mill, and classified to obtain colored particles.
[0111]
To 100 parts of the above colored particles, 1.5 parts of hydrophobic silica used in Example 1 was externally added using a Henschel mixer FM10B to obtain a toner.
[0112]
The toner had a weight average diameter of 6.9 μm, an average circularity of 0.941 by a flow type particle image analyzer, and a standard deviation of the circularity of 0.021.
[0113]
The toner was evaluated in the same manner as in Example 1.
[0114]
<Example 8>
In Example 7, colored particles were obtained in the same manner as in Example 7 except that Kryptron (manufactured by Kawasaki Heavy Industries) was used as a pulverizer.
[0115]
To 100 parts of the above colored particles, 1.5 parts of hydrophobic silica used in Example 1 was externally added using a Henschel mixer FM10B to obtain a toner.
[0116]
The toner had a weight average diameter of 7.1 μm, an average circularity by a flow type particle image analyzer of 0.972, and a standard deviation of the circularity of 0.039.
[0117]
The toner was evaluated in the same manner as in Example 1.
[0118]
<Comparative Example 1>
100 parts of untreated silica having a primary particle size of about 7 nm are placed in a closed high speed stirrer and stirred while purging with nitrogen. A treatment agent obtained by diluting 12 parts of trimethylchlorosilane with hexane four times is sprayed into a stirrer. After spraying the whole amount of the treatment agent, the temperature inside the stirrer was raised to 300 ° C. while stirring and stirred for 90 minutes. The temperature in the stirrer was returned to room temperature while stirring and then crushed by a pin mill, and the hydrophobicity was 88.0%, A / B = 45.8, B = 2.5, and the primary particle size was about 7 nm. Of hydrophobic silica was obtained.
[0119]
To 100 parts of the colored particles used in Example 1, 1.5 parts of the silica was externally added with a Henschel mixer FM10B to obtain a toner.
[0120]
The toner had a weight average diameter of 6.6 μm, an average circularity by a flow type particle image analyzer of 0.986, and a standard deviation of the circularity of 0.015.
[0121]
The toner was evaluated in the same manner as in Example 1.
[0126]
<Comparative Example 3>
100 parts of untreated silica having a primary particle size of about 12 nm are placed in a closed high-speed stirrer and stirred while purging with nitrogen. A treatment agent obtained by diluting 12 parts of dimethyl silicone oil with hexane three times is sprayed into a stirrer. After spraying the entire amount of the treatment agent, the temperature in the stirrer was raised to 270 ° C. while stirring and stirred for 1 hour. The temperature in the stirrer was returned to room temperature while stirring and then crushed with a pin mill, and the hydrophobicity was 98.1%, A / B = 30.5, B = 5.8, and the primary particle size was about 12 nm. Of hydrophobic silica was obtained.
[0127]
To 100 parts of the colored particles used in Example 1, 1.5 parts of the silica was externally added with a Henschel mixer FM10B to obtain a toner.
[0128]
The toner had a weight average diameter of 6.6 μm, an average circularity by a flow type particle image analyzer of 0.986, and a standard deviation of the circularity of 0.015.
[0129]
The toner was evaluated in the same manner as in Example 1.
[0130]
<Comparative example 4>
100 parts of untreated silica having a primary particle size of about 12 nm are placed in a closed high-speed stirrer and stirred while purging with nitrogen. A treating agent obtained by diluting 16 parts of dimethyldichlorosilane with hexane four times is sprayed into a stirrer. After spraying the whole amount of the treatment agent, the temperature inside the stirrer was raised to 300 ° C. while stirring and stirred for 90 minutes. The temperature in the stirrer was returned to room temperature while stirring and then crushed by a pin mill, and the hydrophobicity was 92.4%, A / B = 66.3, B = 1.0, and the primary particle size was about 12 nm. Of hydrophobic silica was obtained.
[0131]
To 100 parts of the colored particles used in Example 1, 1.5 parts of the silica was externally added with a Henschel mixer FM10B to obtain a toner.
[0132]
The toner had a weight average diameter of 6.6 μm, an average circularity by a flow type particle image analyzer of 0.986, and a standard deviation of the circularity of 0.015.
[0133]
The toner was evaluated in the same manner as in Example 1.
[0134]
<Comparative Example 5>
100 parts of untreated silica having a primary particle size of about 12 nm are placed in a closed high speed stirrer and stirred while purging with nitrogen. A treatment agent obtained by diluting 50 parts of dimethyl silicone oil with hexane four times is sprayed into a stirrer. After spraying the whole amount of the treatment agent, the temperature inside the stirrer was raised to 300 ° C. while stirring and stirred for 1 hour. The temperature in the stirrer was returned to room temperature while stirring and then crushed by a pin mill, and the hydrophobicity was 98.1%, A / B = 7.1, B = 10.5, and the primary particle size was about 12 nm. Of hydrophobic silica was obtained.
[0135]
A toner was obtained by externally adding 1.5 parts of the silica to 100 parts of the colored particles used in Example 1 using a Henschel mixer FM10B.
[0136]
The toner had a weight average diameter of 6.6 μm, an average circularity by a flow type particle image analyzer of 0.986, and a standard deviation of the circularity of 0.015.
[0137]
The toner was evaluated in the same manner as in Example 1.
[0138]
[Evaluation methods]
The fixability is 9.8 kPa (100 g / cm) for the fixed image. ² ) And rubbed with Sylbon paper (Lenz Cleaning Paper “dasper” Ozu Paper Co. Ltd.), and evaluated by the density reduction rate before and after rubbing. The larger the density reduction rate, the worse the fixability. The density was measured with a reflection densitometer RD918 (manufactured by Macbeth).
[0139]
The evaluation results are shown in Table 1.
[0140]
[Table 1]

[0141]
【The invention's effect】
As described above, the film heating and fixing method is carried out after repeating a low printing rate developing operation with a low toner development amount many times by a developing device using an elastic blade as a toner regulating member, particularly in a low temperature and low humidity environment, after many times. Thus, it is possible to form an image with excellent fixability even when fixing with.
[Brief description of the drawings]
FIG. 1 is a schematic view of an example of a film fixing device.
FIG. 2 is a schematic view of an example of a film fixing device.
[Explanation of symbols]
2 Pressure roller
12 Ceramic heater
13 Fixing film
N Fixing nip
P Recording material
t Unfixed toner

Claims (4)

A fixing member and a pressure member that forms a fixing nip portion between the fixing film and a recording material carrying unfixed toner on the surface are heated while being nipped and conveyed to the fixing nip portion. In the image forming method for fixing by
The toner has at least 90% hydrophobicity in colored particles containing at least a colorant and a binder resin, and has a surface silanol content A (number / ( g · 10 ⁻¹⁸ ) ) and carbon content B (mass%). However, the hydrophobic silica which is A / B = 3-30 and B = 4-10 is added, The image forming method characterized by the above-mentioned.   2. The image forming method according to claim 1, wherein the hydrophobic silica has a carbon amount B of 5 to 8. The surface silanol amount A (pieces / ( g · 10 ^-18 ) ) and carbon amount B (mass%) of the hydrophobic silica are A / B = 10 to 25 according to claim 1 or 2. The image forming method described. The toner has an average circularity using a flow-type particle image analyzer is from .950 to .990, any one of claims 1 to 3 standard deviations of the roundness is equal to or 0.035 or less The image forming method described in 1.

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