JPH09304965A - Toner for electrophotography, manufacture of toner for electrophotography, developer for electrophotography, and picture image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide toner for electrophotography which can reduce the use of mold releasing agent its adhesion on a picture image, can make a fixing device compact, provides excellent resistance against offset property, and can obtain high quality picture image. SOLUTION: Toner for electrophotography contains at least binding resin and coloring agent. As for the binding resin, its content of component having molecular weight of 10,000 or less is 45 weight % or less, and polyester resin of which dynamic viscous elasticity satisfies G'' (100 rad-sec)/1000>=30 contains G'' (shows a value of dynamic viscous elasticity in frequency 100 red/sec at a temperature at which (1 rad/sec) becomes 1×10<3> Pa.) Preferably, the temperature at which the G'' (1 rad/sec) becomes 1×10<3> Pa is 180 deg.C or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic toner used in an apparatus utilizing an electrophotographic process such as a copying machine, a printer and a facsimile, particularly a color copying machine (hereinafter, simply referred to as "toner"). A), a method for producing an electrophotographic toner, a developer for electrophotography (hereinafter sometimes simply referred to as “developer”), and an image forming method.

[0002]

2. Description of the Related Art As an electrophotographic process, Japanese Patent Publication No.
There are many known methods including the method described in Japanese Patent Publication No. 23910. In the electrophotographic process, a latent image is electrically formed on a photoreceptor using a photoconductive substance by various means, and the latent image is developed with toner,
After transferring the toner image on the transfer target such as paper with or without the toner latent image on the photosensitive member via the intermediate transfer member, the transferred image is heated, pressurized, heated and pressed, or by solvent vapor or the like. A fixed image is formed through a plurality of steps of fixing. If necessary, the toner remaining on the photoconductor is cleaned by various methods, and the plurality of steps are repeated. In recent years, in such an electrophotographic process, there has been a strict demand for downsizing, weight reduction, speedup, and high reliability of a device to be used. Especially, in the case of a color copying machine,
The formed image is required to have high image quality and high color development. In order to obtain an image with high image quality and high color development, the toner must be sufficiently melted and the surface of the image after fixing should be smooth from the viewpoint of translucency and gloss. Therefore, the fixing step in the electrophotographic process becomes particularly important, and various fixing methods and fixing devices have been developed.

Examples of the fixing method include a non-contact fixing method and a contact fixing method. The non-contact type fixing method is a method of fixing the toner to the transfer target with solvent vapor, heat, etc., and has an advantage that there is no problem such as offset described later. However, when solvent vapor is used, there is a problem in environmental safety, and when heat is used, there is a problem that it is not suitable for speeding up due to poor heat conduction. The contact-type fixing method includes a method using only pressure, a method using heat and pressure (hereinafter referred to as "thermocompression method"), and the like. In the case of the former, there are problems that the toner is not sufficiently deformed and the image surface is not smooth, and the fixing on the transfer target is not sufficient, so that it has hardly been put to practical use. On the other hand, the latter thermocompression bonding method does not have the problem of the former, and is currently most commonly used. In the case of the thermocompression bonding method, since the surface of the fixing member and the toner image on the transfer target come into contact with each other under pressure, the thermal efficiency is extremely good and the fixing can be performed quickly, especially in a high-speed electrophotographic copying machine. It is very effective. However, in the case of the thermocompression bonding method, the surface of the fixing member and the toner image are brought into pressure contact with each other in a heated and melted state, so that a part of the toner image is transferred while being attached to the surface of the fixing member. The phenomenon may occur. In particular, in the case of melting and mixing a plurality of color toners such as color toners, it is necessary to apply sufficient heat and pressure to the toners in order to improve the smoothness of the image after fixing. Conventional color toners are known as sharp melt toners and have a low molecular weight and are easily melted.Therefore, when multiple colors of such conventional toners are melt-mixed, an offset or wrapping phenomenon inevitably occurs. It will be easier. Therefore, in the thermocompression bonding method, prevention of these is the most important issue.

Therefore, conventionally, as a simple method for preventing the toner from adhering to the surface of the fixing member, the surface of the fixing member has been coated with oil such as silicone oil as a liquid for preventing offset. However, when the oil or the like is used, there is a problem that the oil or the like adheres to the transfer-receiving member and the image after fixing, and a tank for storing the oil or the like is required, so that the fixing device is downsized. However, there is a problem that cost reduction is restricted.
The amount of the oil or the like applied to a general transfer target in the past is as large as 8.0 × 10 ⁻² mg / cm ² . This means that 100,000 copies of A4 paper use 5 kg of the oil or the like.

For this reason, a method has been proposed in which the amount of oil or the like applied to the fixing member is reduced while preventing offset from both sides of the toner and the fixing device. As a method for imparting good fixing property and anti-offset property to the toner itself, for example, there are two peaks in the molecular weight distribution of the binder resin used in the toner, that is, in the high molecular weight region and the low molecular weight region. Method a using a resin having a peak (Japanese Unexamined Patent Publication No. 56-158340, etc.), Method b in which a release agent such as wax is added to a binder resin (Japanese Patent Publication No. 52-3304, Japanese Unexamined Patent Publication No. 4-3).
No. 62953), and a method c using a crystalline resin as a binder resin (Japanese Patent Publication No. 57-36586). However, in the case of the method a, not only the offset cannot be sufficiently prevented, but also
Since the high molecular weight component contained in the binder resin does not melt sufficiently, good smoothness of the image surface cannot be obtained, and the color developability deteriorates, which is not suitable for color image formation. In the case of the method b, addition of wax tends to deteriorate chargeability, toner powder fluidity, light transmittance, and the like. Sufficient releasability can be obtained with an addition amount that does not affect these characteristics. No
The use of release agents such as oil is essential. In the case of the method c, the toner adheres to the heat roller, the smoothness of the image surface suitable for a color image cannot be obtained, and the light emitting property is higher than that of the amorphous resin due to the scattering of light by the crystals. Will get worse. JP-A-3-152556 discloses a toner using a styrene-acrylic resin containing 5 to 50% by weight of a component having a molecular weight of 10,000 or less as a binder resin.
However, in the case of this toner, since the offset resistance is compensated by the method in which the above-described method a contains the polymer component, the smoothness of the image surface suitable for a color image cannot be obtained.

On the other hand, in order to prevent the offset by the fixing device, for example, a method d utilizing the strain of the elastic layer of the heating roller (Japanese Patent Laid-Open Nos. 1-312574 and 2-15).
6281, JP-A-2-156283, etc.),
Method e for increasing the curvature of the heating roller (Japanese Patent Laid-Open No. 60-2
No. 07170, etc.), a method f for separating a transfer target by bringing a peeling claw into contact with a heating roller, and a method g using a belt for a fixing member (Japanese Patent Laid-Open No. 59-68766, etc.) are known. There is. Among these, the method d is effective in peeling the toner by utilizing the strain of the elastic layer. However, with conventional color toners having insufficient releasability, a large amount of oil or the like must be applied to the fixing member even with this method d, and further, if the large strain generated in the thick elastic layer is not utilized, offset or It was not possible to prevent wrapping. Therefore, the heat capacity becomes large, it takes a long time to heat the fixing member, and fixing cannot be performed immediately after the power is turned on.

For the above reasons, higher image quality is required for the oilless suitability and instant start property (performance capable of fixing immediately after turning on the power) currently achieved in black and white copying machines. Achieving it with a color copying machine is difficult with conventional techniques, and under the present circumstances, there is a need for a toner that is newly excellent in releasability and capable of obtaining a high-quality color image.

[0008]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems in the prior art, and (1) eliminates or reduces the use of a release agent, and prevents the adherence of oil to a transferred material and an image after fixing. Reduction, downsizing and cost reduction of the fixing device can be achieved. (2) Good offset resistance, (3)
An object of the present invention is to provide an electrophotographic toner, a method for producing an electrophotographic toner, an electrophotographic developer, and an image forming method, which have high image surface smoothness after fixation and high image quality and high color development.

[0009]

The present invention is based on the following findings by the inventors of the present invention. That is, in the case of forming a color image in the electrophotographic process, if the smoothness of the image surface after fixing is low, light is scattered due to minute irregularities on the image surface, so that a bright image cannot be obtained. In order to obtain a clear color image, it is necessary to increase the smoothness of the image surface after fixing,
For that purpose, it is necessary that the binder resin in the fixing step is in a fluid state or a state close thereto in terms of viscoelasticity at the time of melting, and the binder resin in the fixing step is in a fluid state or a state close thereto. If the binder resin does not exist, the binder resin is not sufficiently deformed, or even if it is sufficiently deformed, the elasticity thereof causes recovery of the toner particle shape, and the smoothness of the image surface after fixing does not become high. Therefore, the dynamic viscoelasticity of the binder resin of the electrophotographic toner in the step of fixing the electrophotographic toner is extremely important. In order to obtain a vivid image, the fluidity of the binder resin upon melting is a physical property value indicating the flowability (viscosity) when the binder resin melts in terms of dynamic viscoelasticity (loss elastic modulus ( "G" below
Abbreviated as “)” in a specific range, and further, the molecular weight distribution of the binder resin needs to be in a specific range. Further, as such a binder resin, a polyester resin is preferable, instead of a styrene-acrylic resin which has been frequently used conventionally. In the case of a styrene-acrylic resin, sufficient releasability cannot be obtained even if the conditions of the specific viscoelastic properties and the content of the low molecular weight component in the present invention described below are satisfied. It is a finding that the presence of an ester bond in the main chain of the binder resin effectively acts on the adhesiveness to the fixing member and the ease of peeling deformation.

The electrophotographic toner, the method for producing the electrophotographic toner, the electrophotographic developer, and the image forming method of the present invention for achieving the above object are as follows. The electrophotographic toner of the present invention contains at least a binder resin and a colorant, and the binder resin contains 45% by weight or less of a component having a molecular weight of 10,000 or less, and has a dynamic viscoelasticity. Is G ″ (100 rad / sec) / 1000 ≧ 3
A polyester resin satisfying 0 (here, the G ″ (10
0 rad / sec) means that G ″ (1 rad / sec) is 1
Frequency of 100 rad / se at a temperature of × 10 ³ Pa
The value of dynamic viscoelasticity in c is shown. ). In the electrophotographic toner, the temperature at which the G ″ (1 rad / sec) becomes 1 × 10 ³ Pa is preferably 180 ° C. or lower.

The method for producing the electrophotographic toner of the present invention comprises:
A step of dispersing and dissolving a toner composition containing at least a binder resin and a colorant in a volatile solvent to prepare a dispersion solution,
A step of dispersing the dispersion solution in an aqueous medium, and a step of removing the volatile solvent from the aqueous medium,
The binder resin contains 45% by weight or less of components having a molecular weight of 10,000 or less, and has a dynamic viscoelasticity of G ″.
Polyester resin satisfying (100 rad / sec) / 1000 ≧ 30 (here, G ”(100 rad / s
ec) has G ″ (1 rad / sec) of 1 × 10 ³ Pa
Represents the value of dynamic viscoelasticity at a frequency of 100 rad / sec at a temperature of. ).
In the method for producing an electrophotographic toner, the toner composition is preferably a colored resin composition obtained by melting and kneading the toner composition.

The electrophotographic developer of the present invention is characterized by containing the electrophotographic toner of the present invention and a carrier. In the electrophotographic developer, the carrier is preferably a resin-coated carrier.

The image forming method of the present invention comprises the steps of forming a latent image on a latent image carrier, developing the latent image with an electrophotographic developer, and transferring the developed toner image onto a transfer body. And a fixing step of heating and pressing the toner image on the transfer body, wherein the electrophotographic developer is the electrophotographic developer of the present invention. In the image forming method, the thermocompression bonding has a coating amount of 8.0 × 10 ⁻³ on the fixing member on the side in contact with the toner image on the image support.
It is preferable that the thermocompression bonding is carried out while supplying the release agent so that the amount becomes less than or equal to mg / cm ^2, and the fixing member has an elastic layer having a thickness of 0.01 to 2.0 mm. A fixing member is preferable, and a fixing member having a fluororesin layer having a thickness of 0.005 to 0.2 mm on its surface is preferable.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The electrophotographic toner of the present invention contains at least a binder resin and a colorant. The photographic toner of the present invention further contains other components, if necessary.

The binder resin contains a specific polyester resin. The polyester resin has a dynamic viscoelasticity of G ″ (100 rad / sec) / 1000 ≧
30 (here, the G ”(100 rad
/ Sec), G ″ (1 rad / sec) is 1 × 10 ^3.
It represents the value of dynamic viscoelasticity at a frequency of 100 rad / sec at a temperature of Pa. ), G "(100 rad / s
ec) / 1000 ≧ 40 is preferable,
It is more preferable that G ″ (100 rad / sec) / 1000 ≧ 50 is satisfied. Further, as the dynamic viscoelasticity, the G ″ (100
rad / sec) / 1000 as a lower limit, a lower limit of any one of the lower limits of the numerical range, and any of the lower limits of the above-mentioned numerical ranges or the above-mentioned examples adopted in Examples described later. G "(100 rad / sec)
A numerical range in which any one of the values / 1000 is set as the upper limit value is also preferable.

G "(100 rad / sec) / 10
When the value of 00 is less than 30, the fluidity at the time of melting is poor, and the smoothness of the image surface after fixing may not be sufficient. On the other hand, when it is 30 or more, when heat and pressure are applied to the toner in the fixing step, a transition from a solid state to a fluidized state occurs rapidly, and as a result, the smoothness of the image surface after fixing becomes high. . This is because the value of G "(100 rad / sec) / 1000 is 40
When it is above, it is remarkable, when it is 50 or more, it is more remarkable, and the fixing can be performed at a low temperature. This means that different G "(100 rad / sec) / 100
It is also clear from FIG. 1 showing the relationship between the fixing temperature and the smoothness of the image surface after fixing at 0. Therefore, the larger the value of G ″ (100 rad / sec) / 1000, the higher the smoothness of the image surface, which is advantageous in that fixing can be performed at a lower temperature. The dynamic viscoelasticity of the resin to be coated is, for example, a rotary flat plate type rheometer (RDA2 manufactured by Rheometrics Co.,
RHIOS system ver. Measurement can be performed using 4.3).

The polyester resin has a content of a component having a molecular weight of 10,000 or less (hereinafter sometimes referred to as "low molecular weight component") with respect to the total weight thereof.
It is 45% by weight or less, preferably 40% by weight or less, and more preferably 35% by weight or less. Further, as the content of the low molecular weight component, a numerical range having any one of the values of the content of the low molecular weight component adopted in Examples described below as an upper limit value, and an upper limit of any one of the upper limit values of the numerical range. Also, a numerical range in which any one of the upper limit values of the numerical range or the content value of the low molecular weight component used in Examples described later is set as the lower limit value is also preferable.

The content of the low molecular weight component is 45% by weight.
When it exceeds the above range, the adhesive force of the fused toner to the fixing member is increased when the toner is fused, and peeling defects such as offset, winding, and image unevenness are likely to occur. Even if offset or winding does not occur, the fused toner is less likely to be peeled off from the fixing member, and the smoothness of the image surface after fixing is impaired, so that sufficient color developability may not be obtained. It is considered that such a phenomenon occurs because the component having a molecular weight of 10,000 or less functions as a tackifier during the fixing step.
On the other hand, when the content of the low molecular weight component is 45% by weight or less, such a situation does not occur, and offset, winding, image streaking and the like can be prevented, and when it is 40% by weight or less, the effect is obtained. The effect is more remarkable when it is 35% by weight or less, and it is advantageous in that the offset and the like can be effectively prevented even when fixing is performed at a low temperature. This has a molecular weight of 10,000
It is apparent from FIG. 2 showing the relationship between the fixing temperature and the smoothness of the image surface after fixing in the three cases in which the contents of components of 0 or less are different. Therefore, molecular weight 1
The smaller the content of the component of 10,000 or less, the more advantageous it is that offset, wrapping, image streaking and the like can be effectively prevented, and fixing can be performed at a low temperature.

The above-mentioned molecular weight and molecular weight distribution can be measured by a method known per se, but it is generally measured by gel permeation chromatography (hereinafter abbreviated as "GPC"). For GPC measurement, for example, as a GPC device, manufactured by TOYOSODA: HLC-8
02A, oven temperature 40 ℃, column flow rate 1 per minute
ml, sample injection volume 0.1 ml, sample concentration is 0.5%, Wako Pure Chemical Industries: GPC
It can be carried out using special THF. The calibration curve can be created, for example, using a standard polystyrene sample manufactured by TOYO SODA. The molecular weight and the molecular weight distribution in the present invention are measured as described above.

The content of the component having a molecular weight of 10,000 or less can be measured, for example, as follows. First, the portion of the chart obtained by GPC measurement having a molecular weight of 10,000 or less is cut out and weighed. This is defined as Wa. Next, the portion having a molecular weight of 10,000 or more is cut out and weighed. This is Wb. The value calculated from the formula of Wa / (Wa + Wb) × 100 (%) from each weight can be defined as the content of the component having a molecular weight of 10,000 or less. The molecular weight 1 in the present invention
The content of the components of 10,000 or less is measured as described above. The content of the component having a molecular weight of 10,000 or less is not limited to GPC, but the sample may be subjected to some method such as batch fractionation or column elution fractionation in some narrow molecular weight ranges, at least 25. Sort into more than one category, eg ultracentrifugation, osmotic pressure, Spencer
The molecular weight can be measured by a method or a turbidity measuring method, and the distribution can be obtained from the measured values of the weight and molecular weight of each category.

As the polyester resin, G ″ at a frequency of 1 rad / sec is 1 × 1 in dynamic viscoelasticity.
The temperature at which the pressure reaches 0 ³ Pa is preferably 180 ° C or lower. The temperature is related to the fixing temperature, and the temperature is 1
If it exceeds 80 ° C., problems such as increased power consumption and exceeding the heat resistant temperature limit of the fixing member may occur. Although the fixing temperature is low, there is no problem, but the lower limit value is determined by the restriction of the glass transition temperature of the resin as described later.

The glass transition temperature (hereinafter sometimes abbreviated as "Tg") is preferably 50 to 100 ° C, and 6
0-80 degreeC is more preferable. If Tg is less than 50 ° C., the blocking property during storage of the toner may be deteriorated and fusion may occur during pulverization of the toner. If Tg exceeds 100 ° C., the fixing temperature must be increased. This is also not preferable. Tg is measured by using, for example, a differential scanning calorimeter (manufactured by Mac Science Co .: DSC3110, thermal analysis system 001) (hereinafter abbreviated as “DSC”),
The temperature can be measured under the condition of a temperature rising rate of 5 ° C./min, and the temperature of the shoulder on the low temperature side of the endothermic point corresponding to Tg of the obtained chart can be taken as Tg. The Tg in the present invention is measured as described above.

The polyester resin is preferably an amorphous polyester resin. The amorphous polyester resin is advantageous in that, unlike the crystalline polyester resin, the resin itself does not become cloudy due to light scattering by crystals. In the present invention, the amorphous polyester resin means a polyester resin which does not show an endothermic peak corresponding to a crystal melting point in addition to an endothermic point corresponding to Tg in a DSC chart.

The polyester resin is obtained, for example, by reacting a divalent or trivalent or higher carboxylic acid, which is a monomer component, with a divalent or trivalent or higher alcohol. In the present invention, a commercially available product may be used as the polyester resin, or an appropriately synthesized product may be used.

Examples of the divalent carboxylic acid include succinic acid, glutaric acid, adipic acid, speric acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid and naphthalene. Dibasic acids such as -2,7-dicarboxylic acid, cyclohexanedicarboxylic acid, malonic acid and mesaconinic acid, and their anhydrides and their lower alkyl esters, aliphatic acids such as maleic acid, fumaric acid, itaconic acid and citraconic acid An unsaturated dicarboxylic acid etc. are mentioned. Examples of the trivalent or higher carboxylic acid include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,
2,4-naphthalene tricarboxylic acid, etc., their anhydrides, their lower alkyl esters, etc. are mentioned. These may be used alone or in combination of two or more.

Examples of the dihydric alcohol include bisphenol A, hydrogenated bisphenol A, ethylene oxide or (and) propylene oxide adduct of bisphenol A, 1,4-cyclohexanediol, 1,4
-Cyclohexanedimethanol, ethylene glycol,
Diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-
Butanediol, 1,5-pentanediol, 1,6-
Hexanediol, neopentyl glycol and the like can be mentioned. Examples of trihydric or higher alcohols include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. These may be used alone or in combination of two or more. If necessary, a monovalent acid such as acetic acid or benzoic acid, or a monovalent alcohol such as cyclohexanol or benzyl alcohol may be used for the purpose of adjusting the acid value or the hydroxyl value.

The polyester resin may be any combination of these monomer components, for example, polycondensation (chemical coterie), polymer experiment (polycondensation and polyaddition: Kyoritsu Publishing), polyester resin handbook (Nikkan Kogyo). It can be synthesized using a conventionally known method described in, for example,
The transesterification method and the direct polycondensation method can be used alone or in combination. In particular, in order to synthesize a polyester with a high degree of polymerization, it is necessary to increase the purity of the monomer, increase the degree of vacuum for removing reaction by-products, optimize the reaction temperature, optimize the reaction catalyst, etc. It needs to be noted. Further, a polyester resin having a low degree of polymerization can be made to have a high degree of polymerization by using a diisocyanate-containing compound or the like. When the content of the low molecular weight component in the polyester resin produced in this manner is not less than 45% by weight based on the total weight of the polyester resin, it is as shown in the general theory of polymer experiment (Kyoritsu Shuppan). A polyester resin having a low molecular weight component content of 45% by weight or less based on the total weight of the polyester resin can be obtained by treatment according to known fractionation methods such as simple column fractionation method and reprecipitation method, and purification methods.
In the present invention, the polyester resin may be an appropriately synthesized product or a commercially available product.

The criteria for selecting the polyester resin satisfying the conditions of the dynamic viscoelasticity and the content of the low molecular weight component specified in the present invention are as follows. That is, the weight average molecular weight (Mw) is 15,000 to 10
It is preferably 50,000, and preferably from 15,000 to 50,000 in consideration of low-temperature fixability and manufacturability. This is because if the Mw is too large, the heating temperature of the resin during the fixing step becomes too high, and if the Mw is too small, sufficient offset resistance may not be obtained. The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is preferably 10 or less, more preferably 7 or less from the viewpoint of the effect,
It is more preferably 5 or less. The ratio (Mw / M
If n) is too large, the transition from the solid state of the binder resin to the fluid state during melting does not take place rapidly during the fixing step, and as a result, it becomes a factor that reduces the smoothness of the image surface after fixing. Because there is.

However, the molecular weight and the molecular weight distribution obtained from GPC and the like are only one index indicating the length of the polymer, and for example, even resins having the same Mw have a sharp molecular weight distribution, a broad one, and a low molecular weight distribution. There are various types such as one tailed on the molecule side, one tailed on the polymer side, and one having a plurality of peaks. Therefore, it is difficult to show the polyester resin satisfying the conditions of the dynamic viscoelasticity and the content of the low molecular weight component defined in the present invention only by the numerical value of the molecular weight, and the Mw and the ratio (Mw / M
n) is just a guide. The THF-insoluble component in the binder resin, which cannot be measured by GPC, is effective in improving the cleaning property and the offset resistance, but on the other hand, it often reduces the smoothness of the image surface after fixing. In the present invention, a THF insoluble matter may be contained in the binder resin as long as the dynamic viscoelasticity is satisfied.

It is preferable that all of the binder resin is the polyester resin, but for the purpose of improving other electrophotographic characteristics without significantly impairing the effects of the present invention, the content of the polyester resin is May be reduced to about 80% by weight to contain other resins. Examples of the other resin include polystyrene resin, styrene-acrylic copolymer resin, epoxy resin, silicone resin, polyamide resin, polyurethane resin and the like. When the binder resin contains these, effects such as control of adhesion to paper and improvement of charging performance can be obtained. These may be used alone or in combination of two or more, or may be appropriately synthesized,
It may be a commercially available product.

As the polyester resin, a resin having a bond other than an ester bond, a polyester-acrylate resin, a polyester-polyamide resin, etc. may be used for the purpose of improving charging performance without significantly impairing the effects of the present invention. Copolymer resins can also be used.

The colorant is not particularly limited and may be a colorant known per se, which can be appropriately selected according to the purpose. Examples of the colorant include carbon black, lamp black, aniline blue, ultramarine blue, calcoil blue, methylene blue chloride, copper phthalocyanine, quinoline yellow, chrome yellow, DuPont oil red, orient oil red, rose bengal, malachite green. Oxalate, nigrosine dye, C.I. I. Pigment Red 48: 1, C.I. I. Pigment Red 57:
1, C.I. I. Pigment Red 81: 1, C.I. I. Pigment Red 122, C.I. I. Pigment Yellow 9
7, C.I. I. Pigment Yellow 12, C.I. I. Pigment Yellow 17, C.I. I. Pigment Blue 15:
1, C.I. I. Pigment Blue 15: 3 and the like.

The content of the colorant in the electrophotographic toner is 1 to 100 parts by weight of the binder resin.
30 parts by weight is preferable, but it is preferably as large as possible within the range where the smoothness of the image surface after fixing is not impaired. Increasing the content of the colorant is advantageous in that the thickness of the image can be reduced when an image having the same density is obtained, which is effective in preventing offset. Incidentally, yellow toner, magenta toner, cyan toner, black toner and the like can be obtained depending on the kind of the colorant.

The other components are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include various known additives such as inorganic fine particles, organic fine particles, charge control agents and release agents. Can be mentioned.

Examples of the inorganic fine particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth. , Cerium chloride, red iron oxide, chromium oxide, cerium oxide, antimony trioxide, magnesium oxide, zirconium oxide, silicon carbide, silicon nitride and the like. Among these, silica fine particles are preferable, and silica fine particles subjected to hydrophobic treatment are particularly preferable. The inorganic fine particles are generally used for the purpose of improving fluidity. The primary particle diameter of the inorganic fine particles is 1 to 1
000 nm is preferable, and the addition amount thereof is toner 1
0.01 to 20 parts by weight is preferable with respect to 00 parts by weight.

Examples of the organic fine particles include polystyrene, polymethylmethacrylate, and polyvinylidene fluoride. The organic fine particles are generally used for the purpose of improving cleaning property and transfer property. Examples of the charge control agent include salicylic acid metal salts, metal-containing azo compounds, nigrosine and quaternary ammonium salts. The charge control agent is generally used for the purpose of improving chargeability. Examples of the release agent include paraffin wax such as low molecular weight polypropylene and low molecular weight polyethylene, silicone resin, rosins, and rice wax. The release agent is generally used for the purpose of improving releasability.

The electrophotographic toner of the present invention can be manufactured by a manufacturing method known per se. The manufacturing method is not particularly limited and may be appropriately determined depending on the intended purpose. For example, a kneading pulverizing method, a kneading freeze pulverizing method, an in-liquid drying method, and a shear stirring of a molten toner in an insoluble liquid. And a method of dispersing the binder resin and the colorant in a solvent and atomizing them by jet spraying. When the content of the low molecular weight component of the binder resin becomes small, the binder resin becomes hard, and it becomes difficult to pulverize by the various pulverizing methods. In this case, the pulverizability can be improved by increasing the flow rate of jet pulverization or changing the collision plate to a high-strength one such as titanium. Further, organic or inorganic fine particles such as silica, titania, polystyrene and polymethylmethacrylate can be added to the electrophotographic toner as a grinding aid within a range that does not impair the effects of the present invention. If the pulverization is still difficult, the in-liquid drying method can be preferably used.

Among the above-mentioned manufacturing methods, the hardness of the binder resin is not limited, and the electrophotographic toner can be easily manufactured even when a binder resin that is difficult to pulverize is used. The drying method is preferred. The in-liquid drying method is described in, for example, JP-A-63-25664, and a dispersion solution is prepared by dispersing and dissolving a toner composition containing at least the binder resin and the colorant in a volatile solvent. Is a method of preparing the above, a second step of dispersing the dispersion solution in an aqueous medium, and a third step of removing the volatile solvent from the aqueous medium.

In the first step, the toner composition contains at least the binder resin and the colorant, and, if necessary, further contains the other components. The volatile solvent is not particularly limited as long as it can dissolve and disperse the toner composition, and examples thereof include ester solvents such as methyl acetate, ethyl acetate and propyl acetate, ether solvents such as diethyl ether, and methyl ethyl ketone. Examples thereof include ketone solvents such as methyl isopropyl ketone and methyl isobutyl ketone, hydrocarbon solvents such as toluene and cyclohexane, halogenated hydrocarbon solvents such as dichloromethane, chloroform and trichloroethylene. Among these, safety in industrialization,
Cyclohexane and ethyl acetate are particularly preferable in terms of cost and productivity. The volatile solvent preferably has a water-soluble ratio of about 0 to 30% by weight.

The aqueous medium in the second step may be, for example, one in which an inorganic dispersant is dispersed in water and a polymer dispersant is uniformly dissolved. The inorganic dispersant is preferably hydrophilic, and examples thereof include silica, alumina, titania, calcium carbonate, magnesium carbonate, tricalcium phosphate, clay, diatomaceous earth, and bentonite. Of these, calcium carbonate is preferred. The surface of the inorganic dispersant is preferably covered with a polymer having a carboxyl group. Examples of the polymer having a carboxyl group include acrylic acid resins, methacrylic acid resins, fumaric acid resins, and maleic acid resins. In addition, in the present invention, in addition to the polymer, a homopolymer of acrylic acid, methacrylic acid, fumaric acid, maleic acid or the like which is a constituent monomer of the polymer, and a copolymer of these with another vinyl monomer. May be used.
The carboxyl group is, for example, sodium salt,
Metal salts such as potassium salts and magnesium salts may be used. The average particle size of the inorganic dispersant is usually 1 to 100.
0 nm. The inorganic dispersant can be dispersed in the water by using a media-containing disperser such as a ball mill or an ultrasonic disperser.

The polymer dispersant is preferably hydrophilic, particularly preferably has a carboxyl group, and more preferably does not have a lipophilic group such as hydroxypropoxyl group or methoxyl group. Examples of the polymer dispersant include carboxymethyl cellulose and carboxyethyl cellulose. Among these, carboxymethyl cellulose is particularly preferable.
The polymer dispersant has an aqueous medium viscosity of 20 ° C.
It is dissolved in the water so as to be 10,000 mPa · s. The polymer dispersant can be uniformly dissolved in the water by using an appropriately selected means, method, or the like.

The above-mentioned second step can impart a strong shearing force, and can be carried out using an apparatus which is generally commercially available as an emulsifying machine or a dispersing machine. As the device, for example,
Homogenizers (made by IKA), polytrons (made by Kinematica), batch type emulsifiers such as TK auto homomiser (made by Tokushu Kika Kogyo Co., Ltd.), Ebara Milder (made by Ebara Corporation), TK pipeline homomixer (made to special machine) Industrial Co., Ltd., colloid mill (Shinko Pantech Co., Ltd.), slasher, trigonal wet mill (Mitsui Miike Kakoki Co., Ltd.), Cavitron (Eurotec Co., Ltd.), Fine Flow Mill (Pacific Machine Co., Ltd.), etc. High-pressure emulsifiers such as emulsifiers, microfluidizers (manufactured by Mizuho Industry Co., Ltd.), nanomizer E (manufactured by Nanomizer Co., Ltd.), APV gourins (manufactured by Gourin Co., Ltd.), membrane emulsifiers such as membrane emulsifiers (manufactured by Refrigeration Co., Ltd.), vibro Examples include a vibrating emulsifier such as a mixer (made by Cryogenic Industry Co., Ltd.) and an ultrasonic emulsifier such as an ultrasonic homogenizer (made by Branson). It is.

In the third step, the volatile solvent in the aqueous medium is removed by heating and, if necessary, reducing the pressure. The heating temperature is a temperature that does not exceed the glass transition temperature of the binder resin. After removing the volatile solvent, the aqueous medium is removed, washed, dehydrated and the like to obtain electrophotographic toner particles. In the case of performing the washing, dehydration, etc., the aqueous medium may be subjected to an acid treatment, and in some cases, after the acid treatment, an alkali treatment may be performed to dissolve the inorganic dispersant, followed by washing with water, dehydration and the like. .

In the case of the in-liquid drying method, the share of the binder resin may be smaller than that in a pulverizing method such as a kneading pulverizing method, and the dispersibility of the colorant and the other components may be deteriorated. It is particularly preferable to melt-knead the toner composition in advance to obtain a colored resin composition, and dissolve the resin composition in the volatile solvent. According to the in-liquid drying method,
Unlike the above-mentioned various pulverization methods, in which irregular-shaped particles of electrophotographic toner are obtained by pulverization, spherical-shaped particles of electrophotographic toner are obtained. The electrophotographic toner of spherical particles obtained by the in-liquid drying method is more advantageous than the electrophotographic toner of irregular particles obtained by the various pulverizing methods in the following points.

The electrophotographic toner of the present invention is capable of rapidly transferring from a solid state to a melt flow state and has excellent offset resistance. Therefore, when an image is formed using the electrophotographic toner of the present invention, Almost no release agent such as oil is required, the smoothness is high, and it is possible to easily obtain a clear color image with high image quality and high color development. The toner for electrophotography of the present invention exhibits excellent effects other than the above. For example, since the amount of low-molecular weight components is small, improvement in heat storability, improvement in powder fluidity, reduction in the amount of electrophotographic toner dyed onto the transfer material during fixing, and the like are achieved. Also,
By improving the strength of the binder resin, the image strength after fixing is improved, the external additive is prevented from being embedded in the electrophotographic toner, and the electrophotographic toner is strongly conveyed in the developing device or the electrophotographic toner is rubbed by rubbing. It is possible to improve the maintainability of the charging property by preventing crushing, and to stabilize the charging property uniformly by enabling frictional charging under strong stress. Further, by reducing the adhesive force of the binder resin, it is possible to prevent filming on the photoconductor, improve cleaning properties, improve transfer properties, and reduce the amount of external additives used. In particular, these effects are remarkable in the case of the electrophotographic toner having spherical particles obtained by the in-liquid drying method. The electrophotographic toner of the present invention can be preferably used as a toner in an electrophotographic developer.

The electrophotographic developer of the present invention comprises the electrophotographic toner of the present invention. The electrophotographic developer of the present invention may be a one-component electrophotographic developer or a two-component electrophotographic developer containing a carrier, but preferably two components. It is a developer for electrophotography. In the case of the two-component type electrophotographic developer, the carrier is not particularly limited, and a carrier known per se, such as a resin-coated carrier, is preferably exemplified. The resin-coated carrier is obtained by coating the surface of a core material with a resin. Examples of the core material include magnetic powder such as iron powder, ferrite powder, and nickel powder. Examples of the resin include fluororesin, vinyl resin, silicone resin, and the like. The electrophotographic developer of the present invention may contain additives and the like appropriately selected according to the purpose. For example, for the purpose of obtaining magnetism, iron, ferrite, magnets and other irons, metals exhibiting ferromagnetism such as nickel and cobalt, alloys or compounds containing these metals, magnetic materials, magnetizable materials are included. May be.

Since the electrophotographic developer of the present invention contains the electrophotographic toner of the present invention, the advantages of the electrophotographic toner of the present invention can be directly used as the advantages of the electrophotographic developer of the present invention. You can Therefore, when an image is formed using the electrophotographic developer of the present invention, a clear color image having high smoothness, high image quality and high color development can be obtained. The electrophotographic developer of the present invention can be suitably used in various image forming methods.

In the image forming method of the present invention, the electrophotographic developer of the present invention is used as the electrophotographic developer.
The image forming method of the present invention comprises an image forming step known per se, for example, a step of forming a latent image on a latent image carrier, a step of developing the latent image with a developer for electrophotography, a developed toner. It includes a step of transferring the image onto the transfer body, a step of fixing the toner image on the transfer body, and the like. Examples of the fixing include non-contact type fixing and contact type fixing. Among these, contact type fixing is preferable. Examples of the contact-type fixing include fixing using only pressure, thermocompression bonding using heat and pressure, and among these, thermocompression bonding is preferable.

The apparatus for performing the thermocompression bonding is not particularly limited, and a conventionally known apparatus such as the thermocompression bonding apparatus shown in FIG. 3 can be used. The thermocompression bonding apparatus shown in FIG. 3 is an apparatus in which the fixing member has a roller shape, and includes a heat roller 1, a pressure bonding roller 2 arranged to face the heat roller 1, a heat source 10 for heating the heat roller 1, and a heat roller. The roller 1 has a release agent supply device 9 for supplying a release agent 11 to the surface thereof. The thermocompression bonding apparatus shown in FIG.
Even if it has a cleaning member 12 for removing the toner adhering to the surface of the heat roller 1, a heating source 10 for heating the pressure roller 2, a claw (finger) for separating the recording material from the heat roller 1, and the like. Good. The heating source 10 in the thermocompression bonding apparatus shown in FIG. 3 is controlled by a temperature controller (not shown). In the thermocompression bonding apparatus, the combination of rollers and rollers as shown in FIG. 3 may be replaced with the combination of rollers and belts or the combination of belts and belts.

In the thermocompression bonding, a large amount of release agent is usually supplied to the fixing member in order to prevent offset or the like, but an image is formed using the electrophotographic developer of the present invention. In this case, since the offset resistance of the electrophotographic toner of the present invention is extremely excellent, the amount of the release agent supplied to the fixing member can be extremely reduced. In the image forming method of the present invention, in the thermocompression bonding,
The amount of the release agent supplied to the fixing member is 0 mg.
/ Cm ² and the upper limit is 8.0 × 10 ^-3 mg / c
m ² or less (corresponding to 5 mg or less per piece of A4 paper) is preferable, 4.8 × 10 ⁻³ mg / cm ² or less is more preferable, and 1.6 × 10 ⁻³ mg / cm ² or less is further preferable.

The amount of the release agent supplied is preferably small, but when the amount of the release agent supplied is 0 mg / cm ² , the fixing member comes into contact with the transfer target such as paper during the fixing step. At this time, the amount of wear of the fixing member increases, and the durability of the fixing member deteriorates. Therefore, it is practically preferable that a small amount of the release agent is supplied to the fixing member. on the other hand,
When the amount of the release agent supplied exceeds 8.0 × 10 ⁻³ mg / cm ² , the image quality is deteriorated due to the release agent adhering to the image surface after fixing, particularly in the case of OHP. When the transmitted light is used, it appears remarkably. Further, the release agent is remarkably attached to the transferred material, and stickiness occurs. Furthermore, the larger the amount of the release agent supplied, the larger the capacity of the tank for storing the release agent, and the larger the fixing device. Therefore, this case is not preferable in the above points.

The release agent is not particularly limited,
Examples thereof include liquid release agents such as dimethyl silicone oil, fluorine oil, modified oils such as fluorosilicone oil and amino-modified silicone oil. Among these, in order to form a uniform release agent layer by adsorbing on the surface of the fixing member, a modified oil such as amino-modified silicone oil, and for forming a uniform release agent layer because of good wettability to the fixing member. Fluorine oil and fluorosilicone oil, which are ideal, are preferable. The use of fluorine oil and fluorosilicone oil as the release agent is not practical in terms of cost because the amount of the release agent supplied cannot be reduced in the case of the conventional image forming method, In the case of the image forming method of the present invention, since the amount of the release agent supplied can be drastically reduced, there is no practical problem in terms of cost.

The method of supplying the releasing agent to the surface of the heat roller in the thermocompression bonding apparatus is not particularly limited, and examples thereof include a pad method, a web method, a roller method and a non-contact type method in which a liquid releasing agent is impregnated. Shower method (spray method) and the like. Among these, the web method and the roller method are preferable. These methods are advantageous in that the release agent can be uniformly supplied and the supply amount can be easily controlled. In order to uniformly supply the release agent to the entire fixing member by the shower method, it is necessary to use a separate blade or the like.

The amount of the release agent supplied is measured as follows. That is, when plain paper used in a general copying machine (typically, copy paper manufactured by Fuji Xerox Co., trade name J paper) is passed through the fixing member having a release agent supplied on the surface, it is separated onto the plain paper. Mold agent adheres. The release agent on this plain paper is extracted using a Soxhlet extractor. Hexane is used as the solvent. The amount of the releasing agent contained in the hexane is quantified by an atomic absorption spectrophotometer to quantify the amount of the releasing agent attached to the plain paper. This amount is defined as the amount of the release agent supplied to the fixing member.

The fixing member is made of an elastic material such as resin or rubber,
It can be formed by using one kind of various materials known per se such as metal, or by using two or more kinds in combination. The fixing member may contain various additives and the like depending on the purpose, and for example, may contain carbon black, a metal oxide or the like for the purpose of improving wear resistance, controlling resistance value, and the like. In the case of a belt-type fixing member designed to be peeled off after the toner has cooled sufficiently to a solid state, a resin such as fluororesin or the like having excellent releasability in a resin such as polyamide or polyimide is used. It may be formed by mixing, and the releasability may be improved by sacrificing heat resistance to some extent. For the base material (core) of the fixing member, a material having excellent heat resistance, high strength against deformation, and good thermal conductivity is selected. In the case of a roll type fixing device, for example, aluminum, iron, copper, etc. Is selected, and in the case of a belt type fixing device, for example, a polyimide film, a stainless belt, or the like is selected.

The fixing member preferably has a single-layer or laminated elastic layer. When the fixing member has the elastic layer, it is advantageous in that the fixing member is deformed following the unevenness of the toner image on the transfer target, and the smoothness of the image surface after fixing can be improved. . The thickness of the elastic layer is preferably 0.01 to 2 mm, and 0.0
5 to 2 mm is more preferable. The thickness of the elastic layer is 2 mm
If it is too thick, the heat capacity of the fixing member becomes large, it takes a long time to heat the fixing member, and the energy consumption thereof increases, which is not preferable.
Further, if the thickness of the elastic layer is less than 0.01 mm and too thin, the deformation of the fixing member cannot follow the unevenness of the toner image, uneven melting occurs, and distortion of the elastic layer effective for peeling is obtained. It is not preferable because it is not possible.

The material for the elastic layer is not particularly limited and may be appropriately selected depending on the intended purpose. Preferred examples include rubber such as silicone rubber and fluororubber. The thickness of the elastic layer is 0.01 to 2.0 mm
Is preferred.

From the viewpoint of offset resistance and the like, it is preferable that the fixing member has a surface layer having a contact angle with water of 90 ° or more by a droplet method. The surface layer can be provided on the elastic layer as necessary. Preferable examples of the material of the surface layer include resins or rubbers such as fluorine and silicone. Among these, the fluororesin is preferable because it is also excellent in abrasion resistance, and the PFA resin is particularly preferable because it is also excellent in processability among the fluororesins. The thickness of the surface layer is 0.005
0.2 mm is preferable, and 0.01 to 0.1 mm is more preferable. When the thickness of the surface layer exceeds 0.2 mm, the deformation of the fixing member cannot follow the irregularity of the toner image, and the smoothness of the image surface after fixing may be deteriorated, which is not preferable.

Examples of the transferred material (recording material) used in the image forming method of the present invention include plain paper and OHP sheets used in electrophotographic copying machines, printers and the like. In order to further improve the smoothness of the image surface after fixing, it is preferable that the surface of the transferred material is as smooth as possible. For example, coated paper obtained by coating the surface of plain paper with a resin or the like, art paper for printing. And the like can be suitably used as the transferred material.

According to the image forming method of the present invention using the electrophotographic toner and the electrophotographic developer of the present invention, the strength of the image after fixing is high and the release agent hardly adheres to the transferred material. Therefore, it is also possible to produce a seal or a sticker on which a high-quality and high-concentration image is formed by forming an image using a transfer-receiving material such as a sticker or a tape having adhesiveness on the back side. .

[0061]

EXAMPLES Examples and comparative examples of the present invention will be described below, but the present invention is not limited thereto.

(Synthesis of Binder Resin) -Synthesis of Binder Resins A2 (Example) and A1 (Comparative Example) -0.05 mol of the acid component and alcohol component having the compositions shown in Table 1 and the acid component % Dibutyltin oxide was placed in a four-necked flask equipped with a thermometer, a stainless steel stirrer, a nitrogen inlet tube and a condenser,
After introducing nitrogen gas into this flask and maintaining the temperature in an inert atmosphere to raise the temperature, a copolycondensation reaction was carried out at 150 to 230 ° C for about 12 hours, and the pressure was gradually reduced at 210 to 250 ° C to obtain an amorphous structure. Binder resin A1 which is a polyester resin was synthesized.
The characteristics of the binder resin A1 are shown in Table 1. A low molecular weight component was reduced from the binder resin A1 by the following method to obtain a binder resin A2 which was an amorphous polyester resin. That is, while stirring, in a beaker at 25 ° C., completely dissolve 400 g of the binder resin A1 in 2000 g of methylene chloride, and then gradually add 1320 g of isopropyl alcohol,
After stirring for 30 minutes, the mixture was allowed to stand and separated into two layers. The upper layer containing a large amount of low molecular weight components and the lower layer containing a large amount of high molecular weight components were separated. The solvent in the lower layer was evaporated and vacuum dried to obtain Binder Resin A2 which was an amorphous polyester resin.
The characteristics of the binder resin A2 are shown in Table 1. -Binder resins B2 and B3 (example) and C (comparative example)
Synthesis of Binder Resins B1 and C, which are amorphous polyester resins, were synthesized in the same manner as the binder resin A1. In the same manner as in obtaining the binder resin A2, the low molecular weight component and the high molecular weight component were reduced to obtain binder resins B2 and B3 which are amorphous polyester resins from the binder resin B1. The characteristics of the binder resins B1, B2 and C are shown in Table 1. -Synthesis of Binder Resin D (Comparative Example) -90% by weight of styrene and 10% by weight of butyl acrylate
Were polymerized under a cumene reflux (146 to 156 ° C.) in a reactor to synthesize a binder resin D which was a styrene butyl acrylate copolymer. The characteristics of the binder resin D are shown in Table 1.

[0063]

[Table 1]

(Production of Electrophotographic Toner) -Production of Electrophotographic Toners A2, B2 and B3 (Examples) and A1, B1, C and D (Comparative Examples) (kneading and pulverization method) -Synthesis as described above Binder resin A1, A2, B1, B2, B3,
96% by weight of C and D and cyan pigment (cyanine blue 49
33M; 4% by weight of Dainichiseika Co., Ltd. was melt-kneaded with a Banbury type kneader, cooled and coarsely pulverized, and further, with a jet type fine pulverizer, a toner having an average particle diameter of about 7 μm was produced. . 3% by weight of hydrophobic silica powder (R972; manufactured by Nippon Aerosil Co., Ltd.) was added to this toner to manufacture an electrophotographic toner. —Production of Electrophotographic Toner A2 (Liquid Drying Method) — 84% by weight of the synthesized polyester resin A2 and a cyan pigment (cyanine blue 4933M; Dainichiseika Seiki Co., Ltd.)
16% by weight of the product) was melt-kneaded with a Banbury type kneader to obtain a high-concentration colored resin composition. 25% by weight of this colored resin composition and 75 w of the polyester resin A2
t% and 200% by weight of ethyl acetate were dispersed and dissolved to prepare a dispersion solution of cyan pigment weight: polyester resin A2 weight = 4: 96. Carboxymethyl cellulose (serogen BSH; Daiichi Kogyo Seiyaku Co., Ltd.)
Made) and calcium carbonate (luminous (average particle size 0.03μ
m); added to a mixed solution of Maruo Calcium Co., Ltd.) and water, and using a mixer (Cooking Mixer MX915C: manufactured by Matsushita Electric Industrial Co., Ltd.) at 10,000 rpm.
It was stirred at high speed for a minute and dispersed to obtain an emulsion. This emulsion was transferred to a beaker, about 5 times the amount of water was added, and the mixture was kept under stirring in a warm bath of 45 ° C. for 10 hours to evaporate the ethyl acetate. The calcium carbonate was dissolved in hydrochloric acid, and washing with water was repeated to obtain a mixture of water and toner. Finally, water was evaporated in a vacuum dryer at 45 ° C. to prepare a toner. The toner was spherical particles having an average particle size of about 7 microns. 3% by weight of hydrophobic silica powder (R972; manufactured by Nippon Aerosil Co., Ltd.) was added to this toner to manufacture an electrophotographic toner.

(Preparation of Electrophotographic Developer) Electrophotographic Toners A2, B2 and B3 (Examples) and A
7% by weight of each of 1, B1, C and D (comparative example) and 93% by weight of a carrier are mixed to obtain toners A2, B for electrophotography.
2 and B3 (Example), and A1, B1, C and D
An electrophotographic developer corresponding to (Comparative Example) was produced. Regarding the electrophotographic developer A2, two types are used: one using the electrophotographic toner A2 obtained by the in-liquid drying method and one using the electrophotographic toner A2 obtained by the kneading and pulverizing method. It was made. The carrier is a resin-coated carrier, and is a ferrite core coated with a mixture of an amino group-containing vinyl polymer and a fluoroalkyl group-containing vinyl polymer.

(Image formation) The electrophotographic developer A2,
Image formation was performed using B2 and B3 (Examples) and A1, B1, C and D (Comparative Examples), and the following evaluations were performed.

<Evaluation> (1) Fixing Performance Test The electrophotographic developers A2, B2 and B3 (Examples),
Further, using A1, B1, C and D (Comparative Example), an image was formed by an Acolor full-color copying machine manufactured by Fuji Xerox Co., Ltd. with a modified fixing device, and the fixing performance of the electrophotographic toner was evaluated. As the fixing device, the fixing device A shown in FIG. 4 and the fixing device B shown in FIG. 5 were used. The fixing device A is a heat roll fixing device as shown in FIG. In the fixing device A, an elastic layer 4 made of silicone rubber having a thickness of 2.0 mm and a rubber hardness of 40 ° is provided around an aluminum core 3, and the outermost surface of the elastic layer 4 has a thickness of 0.
A heat roller 1 having an outer diameter of 40 mm, which is formed by covering a fluororesin tube of 025 mm with a fluororesin layer 5a, and an elastic layer 4 made of a silicone rubber having a thickness of 1.5 mm and a rubber hardness of 40 ° around an aluminum core 3. And a pressure-applying roller 2 having an outer diameter of 40 mm in which the outermost surface of the elastic layer 4 is covered with a fluororesin tube having a thickness of 0.025 mm and a fluororesin layer 5a is provided. The contact angle of the fluororesin tube forming the fluororesin layer 5a with water was 114 °. The conditions of the fixing performance test are shown below. Toner image → Solid image, toner amount 1 mg / cm ² paper → Fuji Xerox color paper (J paper) OHP → Fuji Xerox transport speed → Paper 120 mm / sec OHP 40 mm / sec Silicone oil application amount → No coating The smoothness of the image surface after fixing is measured by gloss meter G
Using M-26D (manufactured by Murakami Color Research Laboratory Co., Ltd.), the sample fixed on the paper was subjected to the condition that the incident light angle to the sample was 75 °. Table 2 shows the results of the fixing performance test when the fixing device A was used.

[0068]

[Table 2]

The following is clear from Table 2. The electrophotographic toner of the present invention, due to its excellent releasability, can be peeled off even when it is fixed in a highly smooth state, and the electrophotographic toner of the present invention containing the electrophotographic toner of the present invention is included. When images were formed using a developer, it was possible to obtain a color-fixed image with vivid color development. The color developability was satisfied when the gloss value exceeded 40 and the image surface became smooth after fixing. Among them, G "(100 rad / s
ec) / 1000 is 60 or more, the electrophotographic toner A2 has a melting property that facilitates flow and has a lower content of low molecular weight components, and exhibits high smoothness, and is effective in color developability, temperature latitude, and OHP projectability. Was high. On the other hand, the electrophotographic developers A1 and B1 respectively containing the electrophotographic toners A1 and B1 have a large amount of low-molecular weight components and thus have poor releasability and have a high fixing temperature at which smoothness that satisfies color development is achieved. At a temperature lower than the temperature that reached, the peeling failure occurred, and it was wound around the heating roll or offset. The electrophotographic developer C containing the electrophotographic toner C is G ″ (100 rad / sec) / 10.
Since 00 is less than 30, high smoothness was not obtained. The electrophotographic developer D containing the electrophotographic toner D made of a styrene-acrylic copolymer has a releasability in spite of satisfying the dynamic viscoelasticity and the content of the low molecular weight component defined in the present invention. Due to the insufficient property, the electrophotographic developer of the present invention containing the electrophotographic toner of the present invention could not be peeled off in a fixed state with high smoothness.

Next, the toner heat blocking performance was evaluated as follows. That is, first, 5 g of toner was
It was left in a chamber with a humidity of 50% for 24 hours. Then, the temperature was returned to room temperature, and 2 g of the toner was put into a mesh having an opening of 45 μm and vibrated under a constant condition. The weight of the blocking toner remaining on the mesh was measured. Table 3 shows the results.

[0071]

[Table 3]

From Table 3, the following is clear. The spherical toner A2 obtained by the in-liquid drying method exhibits the best heat blocking resistance, and the amorphous toner A2 obtained by the kneading and pulverizing method.
Better than 2. The spherical toner obtained by the in-liquid drying method has a smaller contact area with the adjacent toner than the amorphous toner obtained by the kneading and pulverization method, and thus is presumed to be advantageous for blocking.

The fixing device B is a belt type fixing device as shown in FIG. The fixing device B is provided on the metal belt 6,
An elastic layer 4 made of silicone rubber having a thickness of 0.08 mm and a rubber hardness of 30 ° is provided, and the outermost surface has a thickness of 0.02 mm.
Heating belt 7 provided with a fluororubber layer 5b made of fluororubber, a pressure belt 8 provided with a fluororubber layer 5b made of fluororubber having a thickness of 0.02 mm on the metal belt 6, and a silicone oil as a micro oil supply device. And an impregnating roll (release agent supply device) 9. The contact angle between the surface material of the heating belt and water was 105 °. The conditions of the fixing performance test are shown below. Toner image → Solid image (20 cm × 5 cm: Paper tip) Toner amount 1 mg / cm ² Paper → Fuji Xerox color paper (J paper) OHP → Fuji Xerox transport speed → Paper 180 mm / sec OHP 40 mm / Sec Silicone oil coating amount → 1.6 × 10 ⁻³ mg / cm ² The results of the fixing performance test using the fixing device B are shown in Table 3.
It was shown to.

[0074]

[Table 4]

The following can be seen from the results of Table 4. When the fixing device B is used, the result is almost the same as when the fixing device A is used. When an image was formed using the electrophotographic developer of the present invention containing the electrophotographic toner of the present invention, a color-fixed image with high surface smoothness and clear color development could be obtained.

Next, the electrophotographic toner A2 (cyan
Toner) and the binder resin A2 and magenta
Pigment (Seika Fast Carmine 1476T-7; Dainichi
Seika Co., Ltd., yellow pigment (Seika Fastye)
Rho 2400; Dainichi Seika Co., Ltd.) or carbon bra
(Carbon Black # 25; manufactured by Mitsubishi Kasei Co., Ltd.)
From magenta toner, black toner, and yellow toner, respectively.
A Lautner was prepared. With these toners,
Used as a micro oil supply device in combination with cyan toner
Silicone oil impregnated roll (amount of silicone oil applied
→ 1.6 × 10 ^-Fourmg / cm^Two) The fuser A having
Axor made by Fuji Xerox Co., Ltd.
Full-color copy on 100,000 A4 paper with full-color copier
The fixing device performance maintenance test (image density
Degree: 50% on paper, the fixing device A
No defects were found in.

[0077]

According to the electrophotographic toner, the electrophotographic developer and the image forming method of the present invention, the releasing property from the surface of the fixing device is excellent. It is possible to obtain a color image of high quality that can be reduced to 1/10 or less, that offset does not occur, that the release agent is hardly attached to the transfer target, and that the smoothness is high and the color is vivid. You can In addition, even if a fixing device having a thinner elastic layer of the fixing member than the conventional one is used, offset does not occur, the release agent is hardly adhered to the transfer target, and the smoothness is high. A vivid high-quality color image can be obtained. Further, since the amount of the release agent used is extremely small, the cost and size of the fixing device can be reduced, and the thickness of the elastic layer of the fixing member can be reduced, so that the power consumption can be reduced. On the other hand, according to the method for producing an electrophotographic toner of the present invention, the hardness of the binder resin is not limited, and the electrophotographic toner can be easily produced even when a binder resin that is difficult to pulverize is used.

[Brief description of drawings]

FIG. 1 shows different G ”(100 rad / sec).
6 is an explanatory diagram showing the relationship between the fixing temperature and the smoothness of the image surface after fixing at / 1000. FIG.

FIG. 2 is an explanatory diagram showing the relationship between the fixing temperature and the smoothness of the image surface after fixing in three cases in which the contents of components having a molecular weight of 10,000 or less are different.

FIG. 3 is a schematic explanatory view for explaining an example of a thermocompression bonding apparatus.

FIG. 4 is a schematic explanatory diagram for explaining a fixing device A.

FIG. 5 is a schematic explanatory view for explaining a fixing device B.

[Explanation of symbols]

1 ... Heat roller, 2 ... Pressure roller, 3 ... Core, 4 ... Elastic layer, 5 ... Surface layer, 5a ... Fluororesin layer, 5b ... Fluorine rubber layer, 6 ... Metal belt, 7 ... Heating belt, 8 ... Pressure belt, 9 ...
・ Silicone oil impregnated roll (release agent supply device),
10 ... Heating source, 11 ... Release agent, 12 ... Cleaning member, 21 ... Transferred material such as paper, 22 ...
Unfixed toner

Claims (10)

[Claims] 1. An electrophotographic toner comprising at least a binder resin and a colorant, wherein the binder resin contains 45% by weight or less of a component having a molecular weight of 10,000 or less and a dynamic viscosity. Elasticity is G "(100 rad / se
c) / a polyester resin satisfying 1000 ≧ 30 (here, G ″ (100 rad / sec) is G ″ (1r
It represents the value of dynamic viscoelasticity at a frequency of 100 rad / sec at a temperature at which (ad / sec) becomes 1 × 10 ³ Pa. ) Is contained in the toner for electrophotography. 2. The G ″ (1 rad / sec) is 1 × 1.
The electrophotographic toner according to claim 1, wherein the temperature at which the toner reaches 0 ³ Pa is 180 ° C or lower. 3. A step of dispersing and dissolving a toner composition containing at least a binder resin and a colorant in a volatile solvent to prepare a dispersion solution, a step of dispersing the dispersion solution in an aqueous medium, and the aqueous medium. In the method for producing an electrophotographic toner, including a step of removing the volatile solvent from the inside, the binder resin contains 45% by weight or less of a component having a molecular weight of 10,000 or less, and has a dynamic viscoelasticity. But G ”(1
Polyester resin satisfying 00 rad / sec) / 1000 ≧ 30 (here, G ”(100 rad / se)
(c) represents a value of dynamic viscoelasticity at a frequency of 100 rad / sec at a temperature at which G ″ (1 rad / sec) becomes 1 × 10 ³ Pa). Production method. 4. The method for producing an electrophotographic toner according to claim 3, wherein the toner composition is a colored resin composition obtained by melting and kneading the toner composition. 5. The electrophotographic toner according to claim 1,
A developer for electrophotography, which comprises a carrier. 6. The electrophotographic developer according to claim 5, wherein the carrier is a resin-coated carrier. 7. A step of forming a latent image on a latent image carrier, a step of developing the latent image with an electrophotographic developer, a step of transferring the developed toner image onto a transfer body, and a transfer body. An image forming method including a fixing step of heating and pressing the above toner image, wherein the electrophotographic developer is the electrophotographic developer according to claim 5. 8. The coating amount of the fixing member on the side in contact with the toner image in the thermocompression bonding is 8.0 × 10 ^−3.
8. The image forming method according to claim 7, which is thermocompression bonding performed while supplying a release agent so as to be less than or equal to mg / cm ² . 9. The fixing member has a thickness of 0.01-2.
The image forming method according to claim 8, which is a fixing member having an elastic layer of 0 mm. 10. The fixing member has a thickness of 0.005 to 0.005.
The image forming method according to claim 8 or 9, which is a fixing member having a surface of a fluororesin layer having a thickness of 0.2 mm.