JPH09292735A - Toner, image forming method and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent offset when a film heating type fixing device is used, and to enable fixing under low pressure when a roller fixing device is used, and to decrease wrinkles in a paper sheet. SOLUTION: This toner is prepared as a capsule toner having a core-shell structure comprising a shell part of a sheet resin which is formed to be strong resin and a core part which includes at least a release agent and a material having large thermal expansion. In the image forming method, an image transferred to a recording material with a toner not fixed is fixed by adding <=1.5kg/cm<2> pressure to form a toner image on the recording material. In this method, the toner used is the capsule toner above described.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner used in an image forming method, and more specifically, when fixing an unfixed toner image on a recording material, good fixing without causing offset or paper wrinkles. The present invention relates to a toner, an image forming method, and an image forming apparatus. Further, in the present invention, in the multicolor image forming method, when the toner images of a plurality of colors are sequentially transferred from the image carrier to the intermediate transfer member and then collectively transferred and fixed from the intermediate transfer member to the transfer target material, The present invention relates to an image forming method and an image forming apparatus capable of excellent fixing without offset or paper wrinkles.

[0002]

2. Description of the Related Art As a method for fixing an unfixed toner image formed on a material to be transferred, there is a method using a so-called roller fixing device known in the art as shown in FIG. This roller fixing device is currently in the mainstream, and is composed of a fixing roller Rf having a release layer on the surface and a pressure roller Rp having an elastic layer, and at least one of the rollers has a predetermined surface temperature. Heater H to maintain the temperature
Are arranged. Further, the fixing roller Rf and the pressure roller Rp are in pressure contact with each other, and the transfer material P having the unfixed toner image Ta is nipped and conveyed between these rollers, whereby heat and pressure are applied. The toner image is fixed on the transfer material P by and.

The conventional roller fixing device as described above has an advantage that the structure is relatively simple, but has the following problems. (1) Since the heat capacity of the roller is large, it takes time to reach the temperature at which the toner can be fixed on the transfer material, and the warm-up time becomes long. (2) In addition to the fixing operation, for example, even in a standby state, the heating element inside the roller must be appropriately energized to generate heat to adjust the temperature. Contrary to energy conservation trends.

As a fixing device capable of attaining the fixing temperature in a relatively short time and achieving energy saving in order to solve such problems, it is required to have high heat resistance and high releasability as shown in FIG. There is a so-called film fixing device in which a heater 403, which is a heat source, heats toner via the film 401 included therein, and thereby fixes an unfixed toner image on the transfer material P, which is currently in practical use.

Another problem that occurs in the fixing step is the so-called toner offset phenomenon, in which molten toner adheres to the surface of the fixing roller (the film surface in the film fixing device described above). As a countermeasure against this toner offset phenomenon, in order to enhance the releasing property between the fixing roller surface (or film surface) and the toner, a proper amount of releasing agent such as silicone oil is supplied to the fixing roller surface or the like. It is common to provide the means. As the releasing agent supplying means, for example, as shown in FIG. 7, a releasing agent supplying means D for pumping the releasing agent from the releasing agent tank and applying the releasing agent to the surface of the fixing roller by the applying roller is used. A web W, which is a means for cleaning the surface of the fixing roller (or the surface of the film), is impregnated with silicone oil or the like in advance, and the like. However, these methods require a complicated and large-sized device configuration, replenishment of a release agent, treatment of waste oil, and the like, which causes an increase in service cost and the like.

In recent years, in order to obtain the releasing property between the surface of the fixing roller (or the film surface) and the toner, a releasing agent is contained in the toner, and the releasing agent is changed by the heat and pressure at the time of fixing the toner. With the function of eluting from the inside,
So-called capsule toners have been proposed. In the production of such a capsule toner, it is difficult to obtain by a pulverization method generally known as a toner production method.
It is produced by a suspension polymerization method proposed by Japanese Patent Publication No. 36-10231, emulsion polymerization, precipitation polymerization, dispersion polymerization, soap-free emulsion polymerization or seed polymerization.
For example, in the suspension polymerization method, a polymerizable monomer and a colorant which are toner materials, and if necessary, a polymerization initiator, a cross-linking agent, a charge control agent, a release agent, and other additives are uniformly added. After being dissolved or dispersed into a monomer composition, the monomer composition is treated with a continuous phase containing a dispersion stabilizer (for example,
It is dispersed in an aqueous phase) using a suitable stirrer, and at the same time, a polymerization reaction is carried out to obtain toner particles having a desired particle size.
Thereafter, if necessary, a dispersant removing step, a filter washing step, a drying step, and the like are performed, whereby a release agent is included in the inside (core) C of the toner particles as shown in FIG. The portion (shell) S is an encapsulated toner having a core / shell structure formed of a polymer or the like.

[0007]

However, in the encapsulated toner formed as described above, materials such as wax and silicone oil used as the release agent to be included in the core are not used in the developing device. However, there is a problem in that it easily elutes on the shell surface even at room temperature due to mechanical friction of the above. Then, the release agent eluted on the shell surface causes the following problems. (1) The charging characteristics of the toner are changed to cause image defects such as background fog and light density. (2) The individual particles of the toner are made to adhere to each other to form aggregates or deteriorate the fluidity. (3) Secondary adhesion to the surface of the photoconductor to change the photosensitivity or deteriorate transfer efficiency.

On the other hand, the problem of release agent release as described above can be improved by forming the shell portion firmly. However, when the unfixed toner image formed on the transfer paper by using the capsule toner having the shell portion strongly formed is fixed by the film fixing device as described above, the roller as shown in FIG. 7 is used. It was found that the offset of the toner on the film surface was increased compared to the fixing device. As a cause for this, as will be described below, it is conceivable that the pressure applied to the transfer paper is smaller in the film fixing device than in the roller fixing device.

First, in the film fixing device, as shown in FIG. 1, a heating body 403 as a heat source forms a linear electric heating layer 403b on, for example, an alumina substrate 403a, and a surface protection is provided on the upper surface thereof. By forming the layer 403c of heat-resistant glass, the heat capacity can be reduced, the fixing temperature can be reached in a relatively short time, and energy saving can be achieved.
However, the film fixing device having the above structure is
The mechanical strength due to the contact of the heating element 403 with the pressure roller 402 is extremely poor.

Further, since the heating element 403 thermally expands and contracts depending on the presence or absence of energization, if mechanical bending stress due to contact with the pressure roller 402 is added to this, in the worst case, the heating element This may cause an accident that 403 is broken and leaks. Therefore, in the film fixing device as shown in FIG. 1, the contact pressure (pressure) between the heating means 403 and the pressure roller 402 arranged on the back surface of the film 401 is
0.1-1.0 kg / cm ² , preferably 0.2-
It is set to 0.7 kg / cm ² or less. This value is a low value of half or less, while the pressure applied by a general roller fixing device is 1.5 kg / cm ² or more. The above pressing force is calculated by the following equation (1). [However, (transfer paper width x nip width) in the above formula (1)
Is the contact area between the fixing roller and the pressure roller. ]

Here, also in the conventional roller fixing device as shown in FIG. 7 described above, fixing the unfixed toner image by a low pressure can reduce the strength of the device,
It is possible to reduce the weight of the apparatus and reduce the cost of parts, and to reduce the stress distortion, so-called paper wrinkle, which is caused by the conveyance of the material to be transferred (paper). The paper wrinkles occur frequently especially when double-sided fixing is performed in which toner images are formed on both surfaces of the transfer material. However, the inventor of the present invention uses the conventional roller fixing device and applies a pressure of about 0.7 kg / cm ² which is almost the same as that of the film fixing device shown in FIG. When we conducted a fixing experiment,
It was found that the offset of the toner to the roller surface increased almost in the same way as in the case of the film fixing device.

As described above, it is considered that the increase in the fixing offset when the capsule toner is used is not due to the difference in the constitution of the fixing device but is due to the pressing force. That is, as described above, in order to prevent the release agent and the like in the core from elution before the fixing step, if the shell of the capsule toner is made to have a strong shell portion, the shell is appropriately broken during fixing. However, the release agent in the core cannot be eluted at the interface between the toner particles and the roller or film, and the release effect is considered to be reduced.

Therefore, an object of the present invention is to reach a temperature at which unfixed toner can be fixed on a transfer material in a short time, to enable quick start, and to perform standby temperature control in which the heating body is previously energized to generate heat. When using a film heating type fixing device that can realize energy saving without
An object of the present invention is to provide a toner, an image forming method, and an image forming apparatus that enable good fixing without causing offset. Further, an object of the present invention is that even when a general roller fixing device is used, no special releasing agent supply means is required, fixing can be performed with a low pressure without causing an offset, and a transfer target To provide a toner, an image forming method and an image forming apparatus capable of reducing paper wrinkles due to stress distortion in a nip portion between a fixing roller and a pressure roller of a material (paper).

[0014]

The above object is achieved by the present invention described below. That is, the present invention is a capsule toner having a core / shell structure comprising a shell portion which is firmly formed of an outer shell resin and a core portion which contains at least a release agent material and a material having a large thermal expansion. Or a toner for fixing an unfixed toner image transferred onto a recording material by applying a pressure of 1.5 kg / cm ² or less to form a toner image on the recording material. In an image forming method having a fixing step, the toner is an encapsulated toner as described above, and an image carrier using a plurality of color toners suitable for using the encapsulated toner. A toner image is formed on the upper surface, and a heat-resistant film having a highly releasable surface is used as an intermediate transfer member. First, the toner image on the image carrier is electrostatically transferred onto the heat-resistant film. A copy to step sequentially superimposed and primarily transferred toner images of plural colors on the heat-resistant film by sequentially repeating for each color toner,
Next, in an image forming method in which a plurality of color toner images on the heat-resistant film are collectively secondarily transferred and fixed onto a recording material by heating means provided on the back surface of the heat-resistant film. The image forming method is characterized in that the pressure applied to the toner image on the recording material at the time of transfer and fixing is set to 1.5 kg / cm ² or less.

The toner of the present invention has a core / shell structure in which a shell portion is strongly formed of an outer shell resin, and at least a release agent material and a material having a large thermal expansion are included in the core portion. Since the shell part is strong by using the capsule toner, the release agent material in the core does not elute to the shell surface due to mechanical friction in the developing device, and the core part of the capsule toner does not elute. Since a material having a large thermal expansion is included in the core, the shell part formed by the expansion of the material in the core by heating at the time of fixing is easily broken, and the mold release included together is facilitated. The agent material is configured to be effectively pushed out of the shell at the time of fixing to solve the problems of the prior art. The toner of the present invention is
Especially, when the unfixed toner image is fixed, the pressure applied to the toner on the transfer material is 1.5 kg / cm ² in the fixing step.
It is useful when used in the following image forming method and image forming apparatus.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in detail with reference to preferred embodiments. The encapsulated toner of the present invention has a core / shell structure in which the shell portion is strongly formed of an outer shell resin, and the core portion contains at least a release agent material and a material having a large thermal expansion. Characterize. Hereinafter, first, the components constituting the core portion will be described. As the release agent which is the main component of the core part, a low softening point substance used in a conventional capsule toner, for example, a main body maximum peak value measured according to ASTM D3418-8 is 40 to 90 ° C. Compounds exhibiting are preferably used. Here, if the maximum peak of the release agent is less than 40 ° C., the self-aggregating force of the low softening point substance becomes weak, and as a result, the high temperature offset property becomes weak, which is not preferable. On the other hand, if the maximum peak exceeds 90 ° C., the fixing temperature must be increased, which is not preferable.

In particular, when the toner is obtained by the direct polymerization method as described above, since the granulation and the polymerization are carried out in an aqueous system, if the temperature of the maximum peak value is high, the softening point is mainly lowered during the granulation. It is not preferable because a substance is precipitated and inhibits the suspension system. For the temperature measurement of the maximum peak value of the present invention, for example, DSC-7 manufactured by Perkin Elmer Co. is used. The melting points of indium and zinc were used to correct the temperature of the device detection unit, and the heat of fusion of indium was used to correct the amount of heat. The sample was placed in an aluminum pan, an empty pan was set as a control, and the temperature rising rate was 10 ° C / min. The measurement was performed under the following conditions.

Specific examples of the releasing agent which is a constituent material of the core portion of the toner of the present invention include paraffin wax, polyolefin wax, Fischer-Tropsch wax, amide wax, higher fatty acid, ester wax and derivatives thereof. Or these graft / block compounds etc. are mentioned. The release agent selected from the low softening point substances as described above is contained in the toner in an amount of 5 to 30% by weight.
It is preferable to add in the range. The release agent content is
If the addition amount is less than 5% by weight, the offset becomes significantly worse,
On the other hand, if it exceeds 30% by weight, even in the production by the polymerization method, the toner particles are likely to coalesce with each other during granulation, and particles having a wide particle size distribution are likely to be produced, which is not preferable.

Further, the swelling agent, which is another material for forming the core portion of the toner of the present invention, is a component to be included in the core portion together with the above-mentioned releasing agent. For example, a volatile organic solvent or the like is preferably used. To be Specific examples thereof include conventionally known volatile organic solvents such as isobutane, pentane, petroleum ether, hexane, heptane, low-boiling halogenated hydrocarbons and methylsilane, or a mixture thereof. Further, the expanding agent as described above is preferably added to the toner in an amount of 2 to 20% by weight, more preferably 3 to 15% by weight. If the content of the expanding agent is less than 2% by weight, the expansion coefficient in the toner at the time of fixing is insufficient, and it is difficult to optimally disintegrate the capsule toner having a strong shell portion. When the content is more than weight%, the expansion coefficient inside the toner is too large and the toner image is disturbed, which is not preferable.

Examples of the outer shell resin which is the material for forming the shell portion which is the outer shell of the core portion of the toner of the present invention include the styrene- (meth) acrylic copolymer and polyester. Resin, epoxy resin, styrene-
Butadiene copolymers can be used, and in the case of a method of directly obtaining a toner by a polymerization method, those monomers are preferably used. Specifically, for example, styrene, o- (or m-, p-) methylstyrene, m-
(Or p-) ethyl styrene and other styrenic monomers;
Methyl (meth) acrylate, ethyl (meth) acrylate,
(Meth) propyl acrylate, butyl (meth) acrylate,
Octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, (meth) acrylic (Meth) acrylic acid ester type monomers such as diethylaminoethyl acid ester; butadiene, isoprene, cyclohexene,
Monomers having a reactive double bond such as (meth) acrylonitrile and acrylic acid amide are preferably used.

In the present invention, as the material used for the outer shell resin, the above-mentioned materials are used alone or generally, so that the shell portion of the capsule toner is firmly formed.
The above-mentioned monomers are appropriately used so that the theoretical glass transition temperature (T _g ) described in “Polymer Handbook, Second Edition III, pages 139 to 192 (manufactured by John Wiley & Sons)” is 40 to 75 ° C. It is preferable to use them as a mixture. When the theoretical glass transition temperature of the outer shell resin is lower than 40 ° C., problems occur in terms of storage stability of toner and durability stability of developer. That is, for example, the mold release agent in the core portion is likely to be eluted on the shell surface even at room temperature due to mechanical friction in the developing device, which may change the charging characteristics of the toner or contaminate the surface of the photoconductor to cause photosensitization. It deteriorates the photosensitivity of the body and the transfer efficiency of toner at the transfer portion. On the other hand, when the glass transition temperature of the outer shell resin exceeds 75 ° C., it becomes difficult to elute the release agent in the core portion, and it is difficult to optimally supply the release agent in the fixing step. Further, the fixing point of the toner is increased, and in the case of a full-color toner in particular, the color mixing of the color toners becomes insufficient, resulting in poor color reproducibility.
This is not preferable from the viewpoint of improving the image quality because it significantly reduces the transparency of the P image.

The molecular weight of the outer shell resin constituting the toner shell is measured by GPC (gel permeation chromatography). As a method for measuring GPC, for example, the toner is extracted in advance with a Soxhlet extractor for 20 hours with a toluene solvent, and then the toluene is distilled off with a rotary evaporator to dissolve the low softening point substance, but the outer shell is dissolved. After the resin is thoroughly washed by adding an insoluble organic solvent such as chloroform, T
A solution soluble in HF (tetrahydrofuran) is filtered through a solvent-resistant membrane filter having a pore size of 0.3 μm to obtain a measurement sample. As the measuring instrument, 150C manufactured by Waters Co. was used, and the column configuration was A- manufactured by Showa Denko.
801, 802, 803, 804, 805, 806, 8
07 is ligated and the molecular weight distribution is measured using a calibration curve of standard polystyrene resin. In the present invention, the number average molecular weight (Mn) of the resin component measured as described above is 5,
000 to 1,000,000 and the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (Mw / M
A resin in which n) is 2 to 100 is preferably used as the outer shell resin.

In the present invention, when a toner having a core / shell structure is manufactured, a release agent composed of a low softening point substance and volatilization as a swelling agent are contained in an outer shell resin composed of the above-mentioned material. In order to encapsulate the organic solvent,
It is particularly preferable to add a polar resin in addition to the material for forming the outer shell resin as described above. As the polar resin used in the present invention, a copolymer of styrene and (meth) acrylic acid, a maleic acid copolymer, a saturated polyester resin, an epoxy resin and the like are preferably used. It is particularly preferable that the polar resin does not contain an unsaturated group capable of reacting with the shell resin or the monomer in the molecule. If it contains a polar resin having an unsaturated group, it will undergo a crosslinking reaction with the monomer forming the outer shell resin layer, and in particular, it will have an extremely high molecular weight as a full-color toner. Is too strong, which is disadvantageous in mixing four-color toners, which is not preferable.

Further, in the toner of the present invention, an outermost shell resin layer may be further provided on the outer shell resin layer made of the above material. At this time, in order to further improve the blocking resistance, the glass transition temperature of the outermost shell resin layer is designed to be equal to or higher than the glass transition temperature of the outer shell resin layer, and further crosslinked so as not to impair the fixing property of the toner. It is preferable that or,
The outermost shell resin layer preferably contains a polar resin and a charge control agent in order to improve the charging property. The method for providing the outermost shell layer is not particularly limited, but for example, the following method may be mentioned. (1) After the second half or after the completion of the polymerization reaction for toner production, a monomer in which a polar resin, a charge control agent, a cross-linking agent, etc. are dissolved and dispersed is added to the reaction system, if necessary, and adsorbed on the polymer particles, A method of performing polymerization by adding a polymerization initiator. (2) If necessary, emulsion-polymerized particles made of a monomer containing a polar resin, a charge control agent, a cross-linking agent, or the like, or soap-free polymerized particles are added to the reaction system to agglomerate them on the surface of the polymerized particles. A method of fixing the toner particles onto the surface of the toner particles by heat or the like. (3) A method of mechanically adhering emulsion-polymerized particles or soap-free polymerized particles composed of a monomer containing a polar resin, a charge control agent, a cross-linking agent, etc., to the surface of the toner particles by a dry method, if necessary.

As the colorant used in the toner of the present invention, any conventionally known colorant can be used. Examples of the black colorant include carbon black, magnetic materials, and the like.
A color tone adjusted to black using the following yellow / magenta / cyan colorant is used. As the yellow colorant, compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds and allylamide compounds are used. Specifically, C.I. I. Pigment Yellow 12, 13, 1
4, 15, 17, 62, 74, 83, 93, 94, 9
5, 109, 110, 111, 128, 129, 14
7, 168 and the like are preferably used. As the magenta colorant, a condensed azo compound, a diketopyrrolopyrrole compound,
Anthraquinone, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds are used. Specifically, C.I. I. Pigment Red 2, 3,
5, 6, 7, 23, 48: 2, 48: 3, 48: 4,5
7: 1, 81: 1, 144, 146, 166, 169,
177, 184, 185, 202, 206, 220, 2
21, 254 and the like are preferably used. As the cyan colorant, a copper phthalocyanine compound and its derivative, an anthraquinone compound, a basic dye lake compound and the like are used. Specifically, C.I. I. Pigment Blue 1, 7, 1
5, 15: 1, 15: 2, 15: 3, 15: 4, 60,
62, 66 and the like are preferably used. These colorants are
They can be used alone or in a mixture, and can be used in the state of solid solution.

In the case of a color toner, the above-mentioned coloring agents used in the present invention are hue angle, saturation, lightness, weather resistance,
It is selected from the viewpoints of OHP transparency and dispersibility in the toner. The amount of the colorant added is preferably in the range of 1 to 20 parts by weight with respect to 100 parts by weight of the resin.
However, when a magnetic substance is used as the black colorant, unlike other colorants, it is 40 to 150 parts by weight with respect to 100 parts by weight of the resin.
Add in parts by weight.

Further, in the encapsulated toner of the present invention, by coating the surface of the toner with an external additive, the charging characteristics and fluidity of the toner can be controlled. The external additive used in the present invention has a particle diameter of 1/3 or less, preferably 1/10 or less of the weight average particle diameter of the toner particles from the viewpoint of durability when added to the toner. It is desirable to do. Here, the particle size of the additive means the average particle size thereof obtained by observing the surface of the toner particles with an electron microscope. Examples of the external additive include metal oxides such as aluminum oxide, titanium oxide, strontium titanate, cerium oxide, magnesium oxide, chromium oxide, tin oxide and zinc oxide, nitrides such as silicon nitride, and carbides such as silicon carbide. , Metal salts such as calcium sulfate, barium sulfate and calcium carbonate, fatty acid metal salts such as zinc stearate and calcium stearate, carbon black and silica. The amount of these external additives added is preferably 0.01 to 10 parts by weight, and more preferably 0.05 to 5 parts by weight, based on 100 parts by weight of the toner particles. These external additives may be used alone or in combination. Furthermore, it is preferable to use those that have been respectively subjected to a hydrophobic treatment.

As a method for producing the encapsulated toner of the present invention having the above-mentioned constitution, a molten mixture is atomized in the air using a disk or a multi-fluid nozzle described in Japanese Patent Publication No. 56-13945. A method of obtaining spherical toner,
JP-B-36-10231 and JP-A-59-5385.
No. 6 and JP-A-59-61842, a method of directly producing a toner by using a suspension polymerization method, or a method of being soluble in a monomer but insoluble in a resulting polymer A dispersion polymerization method in which a toner is directly produced using a water-based organic solvent, or an emulsion polymerization method typified by a soap-free polymerization method in which a toner is produced by directly polymerizing in the presence of a water-soluble polar polymerization initiator is used. It is possible. In the present invention, among the above, the particle size distribution of 4 is relatively easy.
It is particularly preferable to manufacture by a suspension polymerization method under normal pressure or under pressure, which gives a fine particle toner having a sharp particle size distribution of ˜8 μm.

Further, as a specific method of encapsulating the mold release agent and the expanding agent, which are the materials for forming the core portion, in the shell as described above, the polarity of the material in the aqueous medium is changed to the toner. The low-softening point substance is set smaller than the main monomer, and a small amount of a resin or monomer with a large polarity is added, so that the low-softening point substance is coated with an outer shell resin, the so-called core. A toner having a shell structure is obtained. Further, as a method for controlling the particle size distribution of the toner or controlling the particle size, a method of changing the kind or addition amount of a poorly water-soluble inorganic salt or a dispersant having a protective colloid action, mechanical device conditions, for example, rotor Stirring conditions such as peripheral speed, number of passes and stirring blade shape,
Controlling the shape of the container or the solid content concentration in the aqueous solution may be mentioned, and a toner having a predetermined particle diameter can be obtained by these methods.

In the capsule toner formed by the above-mentioned method, the releasing agent x and the expanding agent y in the core, and the expanding agent y in the releasing agent x as shown in FIG. It has a structure in which it is substantially evenly dispersed, or has a structure in which the release agent x contains the expanding agent y as shown in FIG. Since the toner of the present invention has these structures, the unfixed toner image is 1.
Even in the fixing step of fixing on the recording material with a relatively weak pressure of 5 kg / cm ² or less, the expansion agent y expands and the strong outer shell resin forming the shell easily breaks, effectively The release agent x can be discharged to the outside of the shell.
The encapsulated toner having a structure in which the releasing agent x contains the expanding agent y as shown in FIG. 2B has an advantage that the toner has excellent long-term storability.

A charge control agent may be added to the toner of the present invention, if necessary. As the charge control agent used at that time, any of conventionally known charge control agents can be used, but in the case of color toner, in particular, the toner is colorless and the charging speed of the toner is high, and a constant charge amount is stable. It is preferable to use a charge control agent that can be maintained as described above. Further, in the present invention, when the direct polymerization method is used as the method for producing the toner, it is particularly preferable to use a charge control agent which has no polymerization inhibitory property and has no solubilized product in the water system.

Specific compounds used as the charge control agent include, for example, negative compounds such as metal compounds of salicylic acid, naphthoic acid and dicarboxylic acid; polymeric compounds having sulfonic acid and carboxylic acid in the side chains. A boron compound,
Examples thereof include urea compounds, silicon compounds and currys arenes. Further, as a positive type, a quaternary ammonium salt,
Examples thereof include polymer type compounds having a quaternary ammonium salt in the side chain, guanidine compounds and imidazole compounds.
The addition amount of these charge control agents is preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the resin.
However, addition of the charge control agent is not essential in the toner of the present invention. That is, when the two-component developing method is used, triboelectrification with the carrier is used, and also when the nonmagnetic one-component blade coating developing method is used, triboelectrification with the blade member or the sleeve member is positively performed. By using the toner, it is not always necessary to include the charge control agent in the toner.

Further, as a polymerization initiator used when a direct polymerization method is used in producing the toner of the present invention, for example, 2,2'-azobis- (2,4-dimethylvaleronitrile) is used. 2,2'-azobisisobutyronitrile, 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-
Azo-based polymerization initiators such as dimethyl valeronitrile and azobisisobutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-
Examples thereof include peroxide type polymerization initiators such as dichlorobenzoyl peroxide and lauroyl peroxide. The addition amount of these polymerization initiators varies depending on the degree of polymerization of interest, but is generally 0.5 to
It is in the range of 20% by weight. The type of the initiator is slightly different depending on the polymerization method, but it may be used alone or in combination with reference to the 10-hour half-life temperature among the above-mentioned ones.
Further, in the present invention, in order to control the degree of polymerization, it is possible to further add and use a conventionally known crosslinking agent, chain transfer agent, polymerization inhibitor and the like.

Further, in the present invention, as the dispersant used when the toner is manufactured by utilizing the suspension polymerization, for example, as the inorganic oxide, tricalcium phosphate, magnesium phosphate, aluminum phosphate can be used. , Zinc phosphate,
Calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina, magnetic material, ferrite and the like can be mentioned. Examples thereof include polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, starch and the like. In addition, these dispersants are used by being dispersed in an aqueous phase.

The amount of these dispersants added is preferably 0.2 to 10.0 parts by weight based on 100 parts by weight of the polymerizable monomer. Further, as these dispersants, commercially available ones may be used as they are, but in order to obtain dispersed particles having a fine and uniform particle size, an inorganic compound as described above under high speed stirring in a dispersion medium is used. You may use what was manufactured. For example, in the case of tricalcium phosphate, a preferred dispersant for use in the suspension polymerization method can be obtained by mixing an aqueous sodium phosphate solution and an aqueous calcium chloride solution under high-speed stirring.

When the above dispersant is miniaturized, 0.0
You may use together 01-0.1 weight part surfactant. As the surfactant used in this case, specifically, commercially available nonionic, anionic, and cationic surfactants can be used. For example, sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, and sodium octyl sulfate can be used. , Sodium oleate, sodium laurate, potassium stearate, calcium oleate and the like are preferably used.

Specifically, the toner of the present invention can be manufactured by the following manufacturing method using a direct polymerization method. First, in a monomer, a release agent composed of a low-softening substance, a swelling agent, a colorant, a charge control agent, a polymerization initiator,
And other additives, a homogenizer, an ultrasonic disperser, etc., a monomer composition uniformly dissolved or dispersed, in the aqueous phase containing the dispersion stabilizer, a normal stirrer or homo Disperse with a mixer and homogenizer. At this time, preferably, the droplets of the monomer composition have a desired toner particle size,
Granulate by adjusting the stirring speed and time of a stirrer or the like. After that, by the action of the dispersion stabilizer, the particle state is maintained,
In addition, the stirring may be performed to such an extent that precipitation of particles is prevented.
The polymerization is performed at a polymerization temperature of 40 ° C. or higher, generally 50 to 90 ° C. Further, the temperature may be raised in the latter half of the polymerization reaction, and further, for the purpose of improving the durability characteristics of the toner when used in the image forming method of the present invention, unreacted polymerizable monomers and byproducts are removed. For removal, the aqueous medium may be partially distilled off in the latter half of the reaction or after the completion of the reaction. After completion of the reaction, the produced toner particles are collected by washing and filtration and then dried. In the suspension polymerization method, usually monomer system 1
300 to 3,000 as a dispersion medium for 100 parts by weight.
It is preferred to use parts by weight of water.

The average particle size and particle size distribution of the toner can be measured by various methods such as Coulter counter TA-II type or Coulter Multisizer (manufactured by Coulter Co.). In the present invention, Coulter counter TA is used.
-Type II (made by Coulter, Inc.), interface (made by Nikkaki) and PC9 for outputting number distribution and volume distribution
An 801 personal computer (manufactured by NEC) is connected, and a 1% NaCl aqueous solution is prepared using primary sodium chloride as the electrolyte aqueous solution. For example, ISOTO
NR-II (manufactured by Coulter Scientific Japan) can be used. As a measuring method, a surfactant, preferably 0.1 to 5 ml of an alkylbenzene sulfonate is added as a dispersant to 100 to 150 ml of the above aqueous electrolyte solution, and further 2 to 20 mg of a measurement sample is added. The electrolyte aqueous solution in which the sample is suspended is subjected to dispersion treatment by an ultrasonic disperser for about 1 to 3 minutes, and the volume and number of toner of 2 μm or more is measured by the Coulter Counter TA-II type using an aperture of 100 μm. Then, the volume distribution and the number distribution were calculated. then,
Volume-based volume average particle diameter (D _v : median value of each channel is a representative value of channels) and volume variation coefficient (S _v ) obtained from volume distribution, and number-based length average particle obtained from number distribution The diameter (D ₁ ) and the coefficient of variation of length (S ₁ ) and the weight-based coarse powder amount (8.00 μm or more) obtained from the volume distribution,
The number-based fine powder amount (5 μm or less) determined from the number distribution was determined.

Next, the image forming method and the image forming apparatus of the present invention in which the capsule toner of the present invention having the above-mentioned structure is preferably used will be described. FIG. 3 is a configuration diagram showing an example of an electrophotographic image forming apparatus capable of forming a good color image using the toner of the present invention.
Specifically, this image forming apparatus includes a printer unit 1 and a reader unit 2, and the printer unit 1 constitutes a recording material conveyance system I on the lower right side of the drawing and the recording material conveyance system I. The latent image forming section II provided near the transfer drum 110 rotatable in the direction of the arrow in the figure, and the developing means arranged in the latent image forming section II provided on the left side of the printer section 1. That is, the rotary developing device III and the printer unit 1
And a fixing device V on the upper right side of the.

First, the recording material conveying system I includes the printer unit 1
Recording material supply cassettes 101 and 102, which are detachable from the opening formed on the right side of the cassette, and paper feed rollers 103 and 104, which are arranged substantially directly above the cassettes 101 and 102, Rollers 103 and 104
Is disposed close to the paper feed roller 105 at both ends thereof.
Paper feed guides 107 and 108 provided with and 106, and further, around the transfer drum 110, a recording material contact roller 109, a gripper 111, and a recording target in order from the lower end to the upper end in the rotation direction. Charger 11 for material separation
4, a separation claw 115, a transfer charger 112 and a recording material separation charger 113, which are provided inside the transfer drum 110. In addition, the separation claw 115 described above
Conveying belt means 116 is provided above the paper feed guides 107 and 108 close to. Further, an image fixing device V including a fixing device 40 and a discharge tray 41 is arranged on the extension of the end portion of the conveying belt means 116 in the conveying direction, that is, on the upper right side of the printer unit 1.

The latent image forming section II is provided in the vicinity of the upper end of the transfer drum 110, and is arranged in contact with the transfer drum 110 and is rotatable in the direction of the arrow (photoconductor drum 20). The photoconductor drum 20 has a cleaning unit 22 provided from the upper end to the side end around the photoconductor drum 20, and a primary charger 21 provided on the photoconductor drum 20. Further, on the outer peripheral surface of the photoconductor drum 20, Is an image exposure means 24 for irradiating a laser beam E for forming an electrostatic latent image,
The image exposure reflection means 25 such as a polygon mirror is provided.

The rotary developing device III provided on the left side of the latent image forming section II includes a rotating body 3 composed of a rotatable casing.
At a position facing the outer peripheral surface of the photoconductor drum 20, the electrostatic latent image on the photoconductor drum is visualized, that is, mounted on the rotating body 3 configured to develop the electrostatic latent image with toner. Yellow developing device 3Y, magenta developing device 3
M, a cyan developing device 3C, and a black developing device 3Bk. In each of the developing units, for example, the capsule toner of the present invention is mounted together with a carrier that is magnetic particles in the form of a so-called two-component developer. As the developer, in addition to the above two-component developer, the toner of the present invention is used alone.
It is also possible to use it in the form of a so-called one-component developer.

In the image forming apparatus as described above, the photosensitive drum 20 rotates in the direction of the arrow shown in FIG. 3, and the photosensitive drum 20 is moved by the primary charger 21 to have a surface potential of −6.
When uniformly charged to 70 V, first, image exposure is performed by the laser light E PW-modulated according to the yellow image signal of the original, and an electrostatic latent image of the yellow image is formed on the photoconductor drum 20. Next, the electrostatic latent image of the yellow image is developed by the rotation of the rotating body 3 of the developing device III by the yellow developing device 3Y in which the yellow toner is mounted in advance at the developing position. At this time, as the developing bias applied to the developing sleeve of the yellow developing device 3Y, the alternating voltage value V _pp is 2 kV, and V _DC is superimposed on the rectangular wave alternating voltage having a frequency of about 2 kHz, and V _cont is 2.
_VDC to be superimposed so as to be about 60V is set to about -410V.

On the other hand, the paper feed guide 10 shown in FIG.
The recording material (not shown) conveyed through the sheet feeding roller 106, the sheet feeding roller 106, and the sheet feeding guide 108 is held by the gripper 111 at a predetermined timing, and the contact roller 10
It is wound around the transfer drum 110 electrostatically by 9 and the electrode facing this. The transfer drum 110 is rotating in the direction of the arrow in synchronization with the photosensitive drum 20,
The electrostatic latent image on the photoconductor drum 20 is the yellow developing device 3Y.
Is visualized in. The visualized yellow toner image is transferred onto the recording material by the transfer charger 112 at the portion of the transfer drum 110 that is in contact with the outer peripheral surface of the photoconductor drum 20.

After that, the transfer drum 110 continues to rotate while holding the recording material to prepare for the transfer of the next color (magenta in FIG. 3). On the other hand, the photosensitive drum 20
After being cleaned by the cleaning means 22,
It is charged again by the primary charger 21 and is subjected to image exposure according to the next magenta image signal. Further, the rotating body of the developing device III rotates while the electrostatic latent image according to the magenta image signal is formed on the photosensitive drum 20 by the image exposing means, and the magenta developing device 3M is moved to the developing position. After being fixedly placed, predetermined magenta development is performed, and the magenta toner image is transferred onto the recording material in the same manner as in the case of the yellow toner image described above.

Subsequently, the above-mentioned process is carried out respectively.
When the transfer of four colors onto the recording material is completed for cyan and black, the visible images of the four colors formed on the recording material are discharged by the charging devices 113 and 114. ,
The gripping of the recording material by the gripper 111 is released, and the recording material is transferred to the transfer drum 11 by the separating claw 115.
After being separated from 0, it is sent to the image fixing device 40 by the conveyor belt means 116, mixed and fixed by heat and pressure there, and discharged onto the discharge tray 41 to complete the full-color image formation.

Next, the fixing process using the capsule toner of the present invention, which is carried out by the fixing device 40 used in the image forming apparatus as described above, will be described with reference to FIG. FIG. 1 is a schematic configuration diagram of a film heating type heat fixing device using an endless belt type film material. In the figure, reference numeral 401 denotes an endless belt type thin film heat resistant film material (hereinafter referred to as an endless film or a film), and the details of the configuration of the film 401 will be described later. 402 is a pressure roller, 4
Reference numeral 03 is a heating element (thermal heater), 404 is a drive roller for driving the film, and 405 is a driven roller which also serves as a film tension roller. Drive roller 40
4, the driven roller 405 and the heating body 403 are arranged substantially parallel to each other, and the film 401 is suspended and stretched between these three members.

Driving roller 404 and driven roller 405
Are rotatably supported at their respective ends between bearing members (not shown). The heating element 403 is a stationary member fixedly supported by an immovable member (not shown). The drive roller 404 is rotationally driven counterclockwise in the drawing by a drive system (not shown), and the film 401 is rotated by the drive roller 404. The conveying force is given by the frictional force between the films, and the driving roller 404, while the inner surface of the film 401 slides on the heating surface of the heating body 403,
The driven roller 405 and the heating member 403 are rotationally driven in a counterclockwise direction indicated by an arrow a between the three members, and at a circumferential speed substantially the same as the transport speed of the transfer paper P as a heated material.

The pressure roller 402 is made of a heat-resistant rubber elastic material such as silicone rubber. Like a general pressure roller, a PFA,
A highly releasable skin layer such as PTFE is formed.
As such a pressure roller 402, for example, an outer diameter 30
10 mm on a 7 mm thick silicone rubber layer
Using a PFA tube with a thickness of about 0 μm,
This is arranged on the heating surface of the heating body 403 so as to sandwich the film 401. In the present invention, 1.5 kg / cm
² or less, preferably 0.1 to 1.5 kg / cm ² , and more preferably 0.4 to 0.6 kg / cm ^{2 with} a relatively weak contact force to the lower surface of the heating element. The pressure roller 402 having the above structure rotates in the forward direction of the rotational movement direction of the film 401 at the same speed as the film speed as the film 401 rotates. In the figure,
Reference numeral 406 denotes a felt pad for cleaning and supplying oil, which is brought into contact with the outer surface of the film material 401, and for example, a felt pad impregnated with a release agent such as silicone oil is used.

The heating element 403 is a linear heating element having a low heat capacity and having a longitudinal direction in the axial direction of the film 401 (that is, the direction orthogonal to the rotational movement direction a of the film, hereinafter referred to as the film width direction). is there. In this example, the heater substrate 4
03a and an energization heating element layer 403 formed in a strip shape or a linear shape along the longitudinal direction at a substantially central portion of the lower surface of the substrate.
b and the lower surface of the substrate including this energization heating element layer 403b is about 1
Heat-resistant glass 40 which is a surface protective layer coated with a thickness of 0 μm
3c and the temperature measuring element 40 provided on the upper surface of the substrate 403a.
3d and a heater support 403e for heat-insulating and supporting the substrate 403a.

The heater substrate 403a is a member having heat resistance, insulation and low heat capacity, and the energization heating element layer 403b is
For example, it is a coating layer made of an electric resistance material such as Ag / Pb (silver palladium) / Ta ₂ N and having a thickness of about 10 μm and a width of about 1 to 3 mm formed by screen printing or the like.
The temperature measuring element 403d is, for example, a resistance thermometer having a low heat capacity such as a Pt film coated on the upper surface of the substrate by screen printing or the like.
It is an NTC thermistor or the like having a low heat capacity, which is adhered to a substantially central portion of the upper surface of the substrate with a silicone adhesive or the like having good thermal conductivity.

The heater support 403e is the heating body 403.
Members 403a to 403d are heat-insulated and supported with respect to the fixing device and the entire copying device, and it is desirable that the forming material have heat insulating properties, high heat resistance, and rigidity.
Examples thereof include highly heat resistant resins such as polyphenylene sulfide, polyamide imide, polyimide, polyether ether ketone and liquid crystal polymer, and composite materials of these resins and ceramics, metal, glass and the like.

When the energization heating element layer 403b is energized, heat is generated and the temperature of the heater substrate 403a rises. The temperature of the heater substrate 403a is detected by the temperature detecting element 403d and fed back to a control circuit (not shown) to control the energization of the heating element layer 403b, so that the temperature of the heating element 403 is a predetermined fixing temperature (for example, 180 ° C)
Is controlled. Here, the energization is, for example, a pulsed waveform with a cycle of 20 ms of 100 V DC, and a pulse according to a desired temperature and energy release amount controlled by the temperature measuring element 403d is applied with its pulse width changed. The pulse width at this time is approximately 0.5 to 5 ms. Or AC1
An energization control circuit (not shown) including a triac depending on the heater substrate detection temperature of the temperature detecting element 403d at 00V.
The energizing power is controlled by controlling the phase angle of energizing by.

In FIG. 1, P is a recording material, and an unfixed toner image Ta is carried on the transfer material before being introduced into the fixing device on the left side of the drawing. The transferred material P is
From the image forming mechanism sections II and III, the film 401 is narrowed to enter the heat fixing section N ₁ (pressing contact section, fixing nip section) formed by the heating body 403 and the pressure roller 402, where unfixed. The toner image surface is brought into close contact with the outer surface of the film 401 which is rotationally moved in the same direction at substantially the same speed as the transfer speed of the transfer target paper P and overlaps with the film 401, so that the heat fixing section N ₁ is subjected to a narrow pressure. While passing through. As a result, the unfixed toner image Ta on the transfer material P is heated and pressed in the heat fixing section N ₁ to become the softened and fused toner image Tb. At this time, the material having a large thermal expansion contained in the toner of the present invention is heated and expanded to destroy the shell, and the release agent material contained together is effectively extruded to the surface of the film 401. A release agent is supplied.
As a result, the toner offset phenomenon on the surface of the film 401, which has been a problem in the film fixing device as described above, is effectively prevented.

In the heater support 403e, a steep angle (a bending angle θ of about 50) is formed at the separation portion S (edge portion) having a large curvature of about 2 mm in the heater support 403e.
The driving direction changes at (°). As a result, the film 401
The transferred paper P conveyed through the heat fixing section N ₁ in a state of being overlapped with is transferred to the film 4 at the separating section S.
Curvature separation is performed from 01, and the sheet is discharged and enters a fixing state Tc.

In the heating element 403 having the above structure, the heater substrate 403a, the heating element layer 403b, and the surface protection layer 40 are provided.
3c, the heat capacity of the temperature detecting element 403d is small, since this is insulated by a support 403e, heating fixing unit N ₁
The temperature of the heater substrate 403a at becomes the temperature at which the unfixed toner image can be fixed on the transfer paper P in a short time. Therefore, in the film fixing device having the above configuration,
A quick start is possible, and there is no need to perform standby temperature control in which the heating element 403 is previously energized to generate heat, energy can be saved, and the temperature inside the machine can be prevented.
In the example shown in FIG. 1, the film 401 has an endless belt shape. However, the film 401 is not limited to an endless belt shape, and may be a roller-wound endless long film, which is fed from the feeding shaft to the winding shaft. It is also possible to have a configuration in which the vehicle travels at a predetermined speed via a heating body.

FIG. 4 shows a fixing film 4 used in the present invention.
It is a layer structure cross-sectional schematic diagram which shows an example of 01. In the figure, 40
Reference numeral 1a is a heat-resistant resin which is a base layer (base film) of the fixing film, and its material is, for example, polyester, PET (polyethylene terephthalate), PFA.
(Tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), PTFE (polytetrafluoroethylene), polyphenylene sulfide, polyamide imide, polyimide, polyether ether ketone, a film made of a high heat resistant resin such as a liquid crystal polymer, aluminum, Examples thereof include a metal sheet such as nickel, or a composite material of these and ceramics, metal, glass, or the like.

Reference numeral 401b in the figure denotes a high release layer having a heat resistance of about 5 μm, and the forming material thereof is, for example, a fluororesin such as PET, PFA, PTFE or a fluororubber as in the above-mentioned base layer. , Silicone resin and silicone rubber. In addition, the fixing film 401 made of the above materials has a surface resistance of these heat resistant sheets of 10 or less.
More preferably, it is a low resistance layer of ⁹ Ω or less. The total thickness of the fixing film is preferably 100 μm or less, more preferably 40 μm or less. For example, a polyimide film having a thickness of 20 μm was used as the base layer (base film) 40la of the fixing film, and the high release layer 401b was made to have a low resistance by carbon dispersion.
The one formed by applying a PFA layer having a thickness of μm is used.

In the above description, laser exposure was used as a means for forming an electrostatic latent image, but the present invention is not limited to this, and a digital latent image such as an LED array, a liquid crystal array, or ionography. Forming means and leader 2
It is also effective in a device using so-called analog latent image forming means, which directly forms an image signal as light on the photoconductor without using such image reading means. Further, although an example of application to a full-color image forming apparatus has been described above, it goes without saying that it can also be applied to a single-color image forming apparatus.

FIG. 7 is a diagram showing an image forming apparatus using a roller fixing device which has been generally used in the past. The toner of the present invention is used in a roller fixing device as shown in FIG. The image forming method of the present invention used in an apparatus in which the fixing roller Rf and the pressure roller Rp are arranged in contact with each other with a weak pressing force of 1.5 kg / cm ² or less will be described. That is, even when used in a roller fixing device, the transfer material on which an unfixed toner image is formed by using the encapsulated toner of the present invention containing a release agent material and a material having large thermal expansion. P is the fixing roller R
If the sheet is nipped and conveyed and fixed in a state in which the pressure is adjusted between f and the pressure roller Rp, the occurrence of paper wrinkles is reduced, and good image formation in which the offset phenomenon on the roller surface is prevented is achieved. It will be possible.

The roller fixing process when the capsule toner of the present invention is used will be described below. The recording material P carrying the unfixed capsule toner image Ta formed by the toner of the present invention containing the release agent material and the material having large thermal expansion is not shown in the arrow direction in FIG. It is conveyed by a device and passed by a drive device (not shown) between a fixing roller Rf and a pressure roller Rp which are rotated in the direction of the arrow in the figure, and a halogen heater H passes through the fixing roller Rf and the pressure roller Rp respectively. The unfixed toner image Ta is fixed on the recording material P by the heat and the pressure supplied as described above.

The image fixing device shown in FIG. 7 includes a fixing roller Rf, a pressure roller Rp facing the fixing roller Rf, and a releasing agent applying means D for applying silicone oil or the like as a releasing agent to the fixing roller Rf. A roller cleaning unit W for cleaning the surfaces of the fixing roller Rf and the pressure roller Rp is provided. The fixing roller Rf is composed of, for example, an outer die of about 40 mmφ in which a core metal made of aluminum is coated with a silicone rubber layer, which will be described in detail later.

The pressure roller Rp is, for example, an HTV (high temperature vulcanizing type) having a thickness of about 1 mm on an aluminum cored bar.
An outer die similar to the fixing roller having a silicone rubber layer and a fluororesin layer formed on the surface thereof has a diameter of about 40 mmφ. A halogen heater H as a heating source is provided in at least one of the core of the fixing roller Rf and the core of the pressure roller Rp, and the temperature of the pressure roller Rp is brought into contact with the thermistor. The surface temperature of the fixing roller Rf and the pressure roller Rp is kept constant at about 150 to 180 ° C. by detecting the temperature of the fixing roller Rf and the heater H by a temperature control device (not shown). .

The release agent applying means D is adapted to apply a release agent such as silicone oil to the silicone rubber layer of the fixing roller Rf, but the toner of the present invention contains the release agent. It is a capsulated toner, and is not necessarily required because it is configured to positively supply the release agent to the roller surface. The roller cleaning means W of the apparatus shown in FIG. 7 cleans the surface of the silicone rubber layer of the fixing roller Rf for toner resins, toner external additives such as silica and alumina, and adhered substances such as various components of paper. .

The fixing roller Rf and the pressure roller Rp of the apparatus shown in FIG. 7 are composed of a core metal made of aluminum or the like, and as a rubber layer, methyl type, methyl vinyl type, methyl phenyl type,
A nitrile type or fluor type silicone rubber layer provided with at least one layer is used. The rubber layer raw material is not limited to the above-mentioned silicone rubber, but fluororubber,
Heat-resistant, high-release rubber material such as fluorosilicone rubber,
Alternatively, those having a fluororesin layer provided on the surface thereof are used.

By applying the toner of the present invention to the image forming apparatus having the above-mentioned structure to form an image, good low pressure fixing can be achieved in a general roller fixing device which has been conventionally used. It will be possible. That is, as a result of the above configuration, paper wrinkles due to stress distortion in the nip portion of the fixing roller and the pressure roller with respect to the transfer material (paper) (especially during double-sided fixing in which toner images are formed on both surfaces of the transfer material (The frequency of occurrence was high), and the fixing offset can also be reduced.

FIG. 5 shows an image forming apparatus used in another example of the image forming method of the present invention, which will be described below. A toner image is formed on an image bearing member using a plurality of color toners, and the heat-resistant film having a highly releasable surface in the film type fixing device shown in FIG. 1 is used as an intermediate transfer member. First, the steps of electrostatically transferring the toner image on the image carrier onto the heat-resistant film are sequentially repeated for each color toner, so that the toner images of a plurality of colors are sequentially superposed on the heat-resistant film and primary transfer is performed. Then, by the heating means provided on the back surface of the heat-resistant film, the secondary transfer of thermally transferring and fixing the toner images of a plurality of colors on the heat-resistant film onto the recording material at once is performed. In this case, the image forming method is characterized in that the pressure applied to the toner image on the recording material at the time of transfer fixing is set to 1.5 kg / cm ² or less. That is, in the apparatus of FIG. 5, the heat resistant film in the film type fixing apparatus shown in FIG. 1 described above is used as the intermediate transfer member. Each drawing number in FIG. 5 is the same as that in FIG. A transfer bias of 1 to 2 kV is applied to the core metal of the drive roller 404, which is the transfer roller that is in contact with the photoconductor 1 via the film 401.
An image formed by the capsule toner of the present invention formed on the photoconductor 1 is primarily transferred onto the film 401 serving as an intermediate transfer body. After that, the capsule toner image transferred onto the film 401 is transferred to the pressure roller 402 and the heating member 403.
Is pressed through the film 401 at a pressure of 1.5 kg / cm ²
The material P to be transferred, which is conveyed to the secondary transfer portion which is abutted below, is conveyed at a timing matching the toner image.
It is fixed at the same time as the transfer. In the case of this example as well, similar to the other examples, even though the pressure at the time of fixing the unfixed toner is low, the release agent is effective from the capsule toner due to the expansion material contained in the toner. As a result, the toner offset to the film surface is effectively prevented.

[0068]

EXAMPLES Next, the present invention will be specifically described with reference to Examples and Comparative Examples. Example 1 First, in 710 g of ion-exchanged water, 0.1 M Na ₃ PO ₄ was added.
After adding 450 g of an aqueous solution and heating to 60 ° C., 12,000 was obtained using a TK homomixer (manufactured by Tokushu Kika Kogyo).
Stir at rpm. 68 g of 1.0 M-CaCl ₂ aqueous solution was gradually added to this to prepare an aqueous medium containing Ca ₃ (PO ₄ ) ₂ . On the other hand, a material having the following formulation was heated to 60 ° C. and uniformly dissolved and dispersed at 12,000 rpm using a TK homomixer (made by Tokushu Kika Kogyo).
10 g of a polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile) was dissolved in this to prepare a polymerizable monomer composition. (Monomer): Styrene 165 g n-Butyl acrylate 35 g (Colorant): C.I. I. Pigment Blue 15: 3 15 g (charge control agent): salicylic acid metal compound 3 g (polar resin): saturated polyester (acid value 14, peak molecular weight: 8000) 10 g (release agent): ester wax (melting point 70 ° C.) 50 g (expansion) Agent): Isobutane 40g

Next, the polymerizable monomer composition was added to the aqueous medium obtained above, and the mixture was mixed at 10 ° C. with a TK homomixer at 10,000 rpm at 60 ° C. under N ₂ atmosphere.
After stirring for a minute, the polymerizable monomer composition was granulated. afterwards,
While stirring with a paddle stirring blade, the temperature was raised to 80 ° C. and the reaction was performed for 10 hours. After completion of the polymerization reaction, residual monomers were distilled off under reduced pressure, and after cooling, hydrochloric acid was added to dissolve calcium phosphate, followed by filtration, washing with water, and drying. As a result, colored suspended particles having a sharp particle size distribution with a weight average particle size of about 7.5 μm were obtained.

To 100 parts by weight of the particles obtained above, hydrophobic silica having a specific surface area of 200 m ² / g according to the BET method was externally added, and the suspension-polymerized toner A as the capsule toner of the present invention was added. Obtained. Next, with respect to 5 parts by weight of this toner A, an acrylic-coated ferrite carrier 95 was used.
Two parts by weight were mixed to prepare a two-component developer A. Using this developer A, a toner image fixing experiment was carried out by the film fixing device shown in FIG. 1, and a good image was obtained and there was no fixing offset to the film.

Example 2 First, in 710 g of ion-exchanged water, 0.1 M Na ₃ PO ₄ was added.
After adding 450 g of an aqueous solution and heating to 60 ° C., 12,000 was obtained using a TK homomixer (manufactured by Tokushu Kika Kogyo).
Stir at rpm. 68 g of 1.0 M-CaCl ₂ aqueous solution was gradually added to this to prepare an aqueous medium containing Ca ₃ (PO ₄ ) ₂ . On the other hand, a material having the following formulation was heated to 60 ° C. and uniformly dissolved and dispersed at 12,000 rpm using a TK homomixer (made by Tokushu Kika Kogyo).
10 g of a polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile) was dissolved in this to prepare a polymerizable monomer composition. (Monomer): Styrene 165 g: n-butyl acrylate 35 g (Colorant): Carbon black 15 g (Charge control agent): Salicylic acid metal compound 5 g (Polar resin): Saturated polyester (acid value 14, peak molecular weight: 8000) 10 g (release) Molding agent): Paraffin wax (melting point 60 ° C.) 30 g (expanding agent): Isobutane 15 g

Next, the polymerizable monomer composition was charged into the aqueous medium obtained above, and the mixture was added to a TK homomixer at 60 rpm and 20 rpm at 20 rpm under N ₂ atmosphere.
After stirring for a minute, the polymerizable monomer composition was granulated. afterwards,
While stirring with a paddle stirring blade, the temperature was raised to 80 ° C. and the reaction was performed for 10 hours. After completion of the polymerization reaction, residual monomers were distilled off under reduced pressure in the same manner as in Example 1, and after cooling, hydrochloric acid was added to dissolve calcium phosphate, followed by filtration, washing with water, and drying. As a result, colored suspended particles having a sharp particle size distribution with a weight average particle size of about 7.2 μm were obtained.

To 100 parts by weight of the particles obtained above, hydrophobic silica having a specific surface area according to the BET method of 200 m ² / g was externally added to obtain a suspension-polymerized toner B which is a capsule toner of the present invention. Obtained. Next, with respect to 5 parts by weight of this toner B, acryl-coated ferrite carrier 95
By mixing parts by weight, a two-component developer B was obtained. Using this developer B, a toner image fixing experiment was conducted with the film-type fixing device shown in FIG. 1, and a good image was obtained and there was no fixing offset to the film.

Example 3 First, in 710 g of ion-exchanged water, 0.1 M Na ₃ PO ₄ was added.
After adding 450 g of an aqueous solution and heating to 60 ° C., 12,000 was obtained using a TK homomixer (manufactured by Tokushu Kika Kogyo).
Stir at rpm. 68 g of 1.0 M-CaCl ₂ aqueous solution was gradually added to this to prepare an aqueous medium containing Ca ₃ (PO ₄ ) ₂ . On the other hand, a material having the following formulation was heated to 60 ° C. and uniformly dissolved and dispersed at 12,000 rpm using a TK homomixer (made by Tokushu Kika Kogyo).
10 g of a polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile) was dissolved in this to prepare a polymerizable monomer composition. (Monomer): Styrene 165 g n-Butyl acrylate 35 g (Colorant): C.I. I. Pigment Blue 15: 3 15 g (charge control agent): metal salicylate compound 3 g (polar resin): saturated polyester (acid value 14, peak molecular weight: 8000) 10 g (release agent): ester wax (melting point 70 ° C.) 50 g (expansion) Agent): Pentane 35g

Next, the polymerizable monomer composition was put into the aqueous medium obtained above, and the mixture was mixed at 10 ° C. with a TK homomixer at 10,000 rpm at 60 ° C. under N ₂ atmosphere.
After stirring for a minute, the polymerizable monomer composition was granulated. afterwards,
While stirring with a paddle stirring blade, the temperature was raised to 80 ° C. and the reaction was performed for 10 hours. After completion of the polymerization reaction, residual monomers were distilled off under reduced pressure in the same manner as in Example 1, and after cooling, hydrochloric acid was added to dissolve calcium phosphate, followed by filtration, washing with water, and drying. As a result, colored suspended particles having a sharp particle size distribution with a weight average particle size of about 7.5 μm were obtained.

To 100 parts by weight of the particles obtained above, hydrophobic silica having a specific surface area according to the BET method of 200 m ² / g was externally added to obtain a suspension-polymerized toner C which is a capsule toner of the present invention. Obtained. Next, with respect to 5 parts by weight of this toner C, an acrylic-coated ferrite carrier 95 is used.
By mixing parts by weight, a two-component developer C was obtained. Using this developer C, a toner image fixing experiment was conducted with the film type fixing device shown in FIG. 1, and a good image was obtained and there was no fixing offset to the film.

Comparative Example 1 First, 710 g of ion-exchanged water was added to 0.1 M Na ₃ PO ₄
After adding 450 g of an aqueous solution and heating to 60 ° C., 12,000 was obtained using a TK homomixer (manufactured by Tokushu Kika Kogyo).
Stir at rpm. 68 g of 1.0 M-CaCl ₂ aqueous solution was gradually added to this to prepare an aqueous medium containing Ca ₃ (PO ₄ ) ₂ . On the other hand, a material having the following formulation was heated to 60 ° C. and uniformly dissolved and dispersed at 12,000 rpm using a TK homomixer (made by Tokushu Kika Kogyo).
A polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile) (10 g) was dissolved therein to prepare a polymerizable monomer composition. (Monomer): Styrene 165 g n-Butyl acrylate 35 g (Colorant): C.I. I. Pigment Blue 15: 3 15 g (charge control agent): metal salicylate compound 3 g (polar resin): saturated polyester (acid value 14, peak molecular weight: 8000) 10 g (release agent): ester wax (melting point 70 ° C.) 50 g

Then, the polymerizable monomer composition was charged into the aqueous medium obtained above, and the mixture was mixed at 10 ° C. with a TK homomixer at 10,000 rpm at 60 ° C. under N ₂ atmosphere.
After stirring for a minute, the polymerizable monomer composition was granulated. afterwards,
While stirring with a paddle stirring blade, the temperature was raised to 80 ° C. and the reaction was performed for 10 hours. After completion of the polymerization reaction, residual monomers were distilled off under reduced pressure in the same manner as in Example 1, and after cooling, hydrochloric acid was added to dissolve calcium phosphate, followed by filtration, washing with water, and drying. As a result, colored suspended particles having a sharp particle size distribution with a weight average particle size of about 7.5 μm were obtained.

To 100 parts by weight of the particles obtained above, hydrophobic silica having a specific surface area of 200 m ² / g by the BET method was externally added, and the expanding agent of the comparative example of the present invention was not included. A suspension polymerization toner D which is a capsule toner is obtained. Next, 95 parts by weight of an acrylic-coated ferrite carrier is mixed with 5 parts by weight of this toner D,
A two-component developer D was used. Using this developer D, a toner image fixing experiment was carried out by the film type fixing device shown in FIG. 1. As a result, toner offset was found on the film surface from the initial stage, and the cleaning / oil contacting the film surface was made. The felt pad for supply was significantly soiled.
Further, when the experiment was repeated, the toner to be transferred was contaminated by the offset toner.

Example 4 In Examples 1 to 3 described above, the developer containing the toners of the developers A to C using the capsule toner of the present invention was used, and the film type fixing shown in FIG. A toner image fixing experiment was carried out by the apparatus, but in the present embodiment, the toner images are fixed by using the above-described roller fixing apparatus shown in FIG. 7 using the developers A to C, respectively. An experiment was conducted. At this time, the fixing roller Rf and the pressure roller Rp are
An unfixed toner image was fixed through the recording material during this period by using a member arranged in contact with a low pressure of 0.7 kg / cm ² . As a result, when any of the developers A to C was used, a good image without paper wrinkles was obtained and there was no fixing offset to the film.

Comparative Example 2 In the same manner as in Example 4, using the developer D of Comparative Example, a toner image fixing experiment was conducted with the roller fixing device shown in FIG.
At this time, the fixing roller Rf and the pressure roller Rp are the same as those in the fourth embodiment.
The toner image was fixed through the recording material by using the same apparatus arranged in abutment with a low applied pressure of 0.7 kg / cm ² . As a result, when the developer D was used, an offset phenomenon occurred on the paper as the recording material, and a good image could not be obtained.

Comparative Example 3 In the same manner as in Example 4, using the developer D of Comparative Example, a toner image fixing experiment was conducted with the roller fixing device shown in FIG.
At this time, the fixing roller Rf and the pressure roller Rp are 2.0
Use the one that is placed in contact with the pressure of kg / cm ² .
During this period, the toner image was fixed through the recording material.
As a result, when the developer D of the comparative example was used, wrinkles were generated on the recording medium, and a good image could not be obtained.

Embodiment 5 In this embodiment, as in Embodiment 4, the developers A to C are used, respectively, and the toner images of a plurality of colors shown in FIG. And a heat-resistant film including a heat-resistant film having a highly releasable surface, on which a toner image is electrostatically superposed and sequentially transferred onto the heat-resistant film. Using a so-called simultaneous transfer and fixing type image forming apparatus, which is provided with a secondary transfer portion that transfers and fixes the heat-resistant film to the transfer material collectively by a heating means provided on the back surface of the Image formation was performed. As a result, the heat-resistant film is used as an intermediate transfer member, the primary transfer is performed on the intermediate transfer member, and the secondary transfer of fixing the primary transfer material onto the transfer material at the same time is also performed.
There was no fixing offset to the film, and a good color image was obtained.

Comparative Example 4 In the same manner as in Example 5, the developer D of Comparative Example was used and a so-called simultaneous transfer fixing type image forming apparatus shown in FIG. Secondary transfer was performed to fix the image at the same time as the transfer. As a result, when the developer D was used, an offset to the film occurred, and a good image could not be obtained.

[0085]

As described above, according to the present invention, the toner is a capsule in which, in addition to the release agent material, the material having a large thermal expansion is encapsulated in the strongly formed outer shell resin. Since it is composed of toner, when the toner is heated during fixing, the material with large thermal expansion contained in the capsule toner expands, destroying the strong outer shell resin, and the release agent contained together. Since it is effectively pushed out, problems such as paper wrinkles and offset in image formation are effectively prevented.

In particular, according to the present invention, the pressure applied to the toner is as low as 1.5 kg / cm ² or less in the fixing step of fixing the toner image on the transfer material, and it is applied to the toner transfer material in a short time. It occurred when using a film heating type fixing device that has a quick start property that reaches the fixing possible temperature and does not need standby temperature control to heat and heat the heating element in advance, and can realize energy saving. The problem of fixing offset can be effectively prevented.

Further, according to the present invention, the low pressure fixing (1.5 k
g / cm ² or less), and paper wrinkles due to stress distortion in the nip portion of the fixing roller and pressure roller of the transfer material (paper) (especially when double-sided fixing where toner images are formed on both surfaces of the transfer material) The frequency is high) and good image formation can be achieved.

Further, according to the present invention, an image carrier on which toner images of a plurality of colors are sequentially formed and a heat resistant film having a highly releasable surface are included, and the toner images are statically formed on the heat resistant film. The primary transfer portion that sequentially and electrically transfers the toner images, and the toner images that are primarily transferred by the heating means provided on the back surface of the heat-resistant film, are thermally transferred from the heat-resistant film to the transfer target material all at once. In the so-called simultaneous transfer and fixing type image forming apparatus including a secondary transfer unit that
The problem of fixing offset can be effectively prevented.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a film heating type fixing device used in the present invention.

FIG. 2 is a schematic cross-sectional configuration diagram of the encapsulated toner of the present invention.

FIG. 3 is a schematic configuration diagram showing an embodiment of an image forming apparatus of the present invention.

FIG. 4 is an enlarged sectional view of a film used in a film heating type fixing device used in the present invention.

FIG. 5 is a schematic configuration diagram showing another embodiment of the image forming apparatus of the present invention.

FIG. 6 is a schematic cross-sectional configuration diagram of a conventional capsule toner.

FIG. 7 is a schematic configuration diagram of a roller fixing device used in the present invention.

[Explanation of symbols]

1: Printer part 2: Reader part 3: Rotating body 3Y: Yellow developing device 3M: Magenta developing device 3C: Cyan developing device 3Bk: Black developing device 40: Fixing device 41: Ejection tray 20: Photosensitive drum 21: Primary charging Container 22: Cleaning Unit 24: Image Exposure Unit 25: Image Exposure Reflecting Unit 101, 102: Recording Material Supply Cassette 103, 104: Paper Feed Roller 105, 106: Paper Feed Roller 107, 108: Paper Feed Guide 109: Recording Material contact roller 110: Transfer drum 111: Gripper 112: Transfer charger 114: Recording material separation charger 115: Separation claw 116: Conveyor belt means 401: Film 401a: Base layer (base film) of fixing film 401b: High Release layer 402: Pressure roller 403: Heating body 403a: Heater substrate 403b: Electric power generation Thermal body layer 403c: Surface protection layer 403d: Temperature detecting element 403e: Heater support 404: Driving roller 405: Driven roller 406: Cleaning member Ta: Toner image on transfer material Tb: Softened fused toner image Tc: Toner image in fixed state P: Transfer paper O: Original E: Laser beam S: Surface layer of toner particles (shell) C: Inside of toner particles (core) D: Release agent applying means Rp: Fixing roller Rf: Pressure roller W: Roller cleaning Means H: Heater N ₁ : Heat fixing unit I: Recording material conveying system II: Latent image forming unit III: Rotary developing device V: Fixing device

Claims (10)

[Claims] 1. A capsule toner having a core / shell structure comprising a shell portion which is firmly formed of an outer shell resin, and a core portion which contains at least a release agent material and a material having a large thermal expansion. Toner characterized by. 2. The toner according to claim 1, wherein the release agent material is a low softening point substance, and the material having a large thermal expansion is a volatile organic solvent. 3. A toner fixing step of forming a toner image on a recording material by fixing the unfixed toner image transferred on the recording material by applying a pressure of 1.5 kg / cm ² or less. An image forming method, wherein the toner is the toner according to claim 1. 4. The toner fixing step has a heating means and a pressure roller which are disposed on the back side of the heat resistant film having a highly releasable surface, and the heating means and the pressure roller. The heat-resistant film and the unfixed toner image are transferred between
4. The image forming method according to claim 3, which is a step of nipping and conveying the carried recording material at a pressure of 1.5 kg / cm ² or less to fix an unfixed toner image on the recording material. 5. A toner image is formed on an image bearing member by using toners of a plurality of colors, and a heat resistant film having a highly releasable surface is used as an intermediate transfer member. First, an image is formed on the heat resistant film. By repeating the process of electrostatically transferring the toner image on the carrier for each color toner, the toner images of a plurality of colors are sequentially superimposed and primary-transferred onto the heat-resistant film. An image forming method in which a plurality of color toner images on a heat-resistant film are collectively thermally secondary-transfer-fixed onto a recording material by a heating means provided on the back surface. An image forming method characterized in that a pressure applied to a toner image on a material is set to 1.5 kg / cm ² or less. 6. The image forming method according to claim 5, wherein the toner is the toner according to claim 1. 7. A toner fixing means for fixing an unfixed toner image transferred on a recording material by applying a pressure of 1.5 kg / cm ² or less to form a toner image on the recording material. An image forming apparatus, wherein the toner according to claim 1 or 2 is mounted. 8. The toner fixing means has a heating means and a pressure roller arranged on the back side of a heat resistant film having a highly releasable surface, and the heating means and the pressure roller are combined. Between the heat-resistant film and the recording material on which the unfixed toner image is transferred and carried, a pressure of 1.5 kg / cm ²
The image forming apparatus according to claim 7, which is a unit for nipping and conveying the image to fix an unfixed toner image on a recording material. 9. A heat-resistant film having a highly releasable surface is used as an intermediate transfer member to form a toner image on the image carrier by using toners of a plurality of colors, and the image-bearing member is formed on the heat-resistant film. Means for performing primary transfer by sequentially superposing toner images of a plurality of colors on a heat-resistant film by sequentially repeating the step of electrostatically transferring the above toner image for each color toner; and the back surface of the heat-resistant film. An image forming apparatus having means for collectively thermally transferring and fixing toner images of a plurality of colors from a heat-resistant film onto a recording material by a heating means provided in An image forming apparatus characterized in that a pressure applied to a toner image on a material is 1.5 kg / cm ² or less. 10. The image forming apparatus according to claim 9, wherein the toner is the toner according to claim 1.