JPH07295291A - Electrostatic charge image developing toner - Google Patents

Abstract

PURPOSE:To produce a toner capable of low temp. fixing, wide in temp. range capable of fixing, hardly causes peeling at a bent part and low in environment dependence of static charge characteristic. CONSTITUTION:In an electrostatic charge image developing toner containing resin and a colorant, the resin has less than 10wt.% insoluble matter to tetrahydrofuran (THF) and its soluble matter to THF is composed of a low mol.wt. component having a maximum value at a mol.wt. of 5X10<3> to 5X10<4> in a GPC mo.wt. distribution and a high mol-wt. component having the maximum value at the mol.wt. of 1X10<6> to 5X10<6>, and a ratio of H/L of a larger component (H) than the mol.wt. of 2X10<5> and a smaller component (L) than that is 20/80 to 50/50.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic latent image developing toner used in electrophotography, electrostatic recording, electrostatic printing and the like.

[0002]

2. Description of the Related Art In electrophotography, an electrostatic latent image is usually formed on a latent electrostatic image bearing member composed of a photoconductive photosensitive member by charging and exposure, and then the electrostatic latent image is formed in a binder resin. The toner image obtained by incorporating a colorant and the like into fine particles is developed, and the obtained toner image is transferred and fixed on a support such as transfer paper to form a visible image. On the other hand, the photoconductor is subjected to charge removal after transfer, and then the toner remaining on the photoconductor without being transferred is cleaned and then used for forming the next image. The electrophotographic toner used for forming such a toner image is generally composed of a binder resin in which a colorant is dispersed and contained. As the colorant, carbon black is used for the toner used for forming a black image. Various chromatic dyes and pigments are used for the color toner used for forming a color image.

As the above-mentioned fixing method, a fixing method using a heat roller is adopted because of its simple device structure and easy handling. In the fixing method using a heat roller, the toner image on the sheet to be fixed is brought into contact with the surface of the heat roller, the surface of which is formed of a material having releasability for the toner, under pressure to fix the toner image. In this method, the surface of the heat roller and the toner image on the sheet to be fixed contact under pressure,
The thermal efficiency of fusing the toner image on the sheet to be fixed is extremely good, and the fixing can be carried out quickly, which is very effective.

However, in recent years, there has been a demand for energy saving in a copying machine, and a toner capable of fixing at a low temperature (hereinafter referred to as "low temperature fixing property") capable of reducing the set temperature of the heat roller and reducing power consumption is required. ing. In addition, in a copying machine that fixes at a higher speed, the heat supply to the heat roller cannot keep up even when a large number of copies are made, the temperature of the heat roller drops, and the fixability becomes insufficient, causing the toner image to bend. When it is rubbed or rubbed, there is a problem that it is peeled off at that portion (hereinafter referred to as "folding and fixing resistance").

In order to improve the fixing property of the toner, it is necessary to lower the viscosity at the time of dissolution and increase the adhesion area with the sheet to be fixed. It is known to lower the molecular weight and glass transition point of the binder resin used for this purpose.

On the other hand, when a toner having an improved fixing property is used, the surface of the heat roller and the toner image are in contact with each other under pressure in a molten state, so that part of the toner image adheres to and transfers to the surface of the fixing roller. The re-transfer to the next sheet to be fixed causes so-called offset development, which causes a problem that the sheet to be fixed is stained. Further, for example, in the case of continuously copying a sheet to be fixed having a small conveyance width, the heat roller draws heat from the sheet to be fixed to lower the temperature, but heat is stored in a portion which is not in contact with the sheet to be fixed. Temperature rises, and the temperature difference becomes very large. After that, when the sheet to be fixed having a large conveyance width is fixed, a part of the toner image adheres to and transfers to the surface of the fixing roller due to the temperature difference generated in the axial direction of the heat roller, which causes an offset phenomenon.

Therefore, a wide fixing temperature range (hereinafter referred to as "fixing region") is required in which the fixing property is good and the offset phenomenon does not occur, but toner is not attached to the surface of the fixing roller. For this purpose, it is effective to improve the viscoelasticity when the toner is melted, and for this purpose, it is necessary to increase the glass transition point and the molecular weight of the binder resin.

Therefore, since the low temperature fixability and the offset resistance have the opposite sides, it is very difficult to satisfy these functions at the same time.

Further, since the durability of toner is greatly deteriorated when the electric resistance characteristic of the toner is greatly changed due to environmental changes, in particular, changes in humidity and temperature, it is required to suppress environmental dependence and form stable images at all times. To be

As a technique relating to the improvement of toner, Japanese Patent Laid-Open No. 1-219767 discloses that the binder resin of the toner contains 10 to 60% by weight of tetrahydrofuran insoluble matter and GP.
In the molecular weight distribution in C, Mw / Mn is 5 or more, 1 peak is in the molecular weight range of 2000 to 10,000, 15,000 to 10,000 peaks or shoulders, and 2.5 million or more peaks or shoulders. Toners having a specified size ratio have been proposed. However, in this technology, the amount of tetrahydrofuran insolubles is as high as 10 to 60% by weight, so the softening temperature of the toner becomes high, and the adhesive strength of the toner to the sheet to be fixed is low, so it is resistant to bending and fixing when it is bent or rubbed. However, there is room for improvement in environmental dependence.

Japanese Unexamined Patent Publication (Kokai) No. 3-138656 discloses a binder resin of 5
-50% is a styrene-acrylic acid methyl ester copolymer, and further the Mw, gel content and Tg of the copolymer are
A toner having a specified range has been proposed. According to this technique, since the Mw is large and the gel content is as high as 15 to 50%, the fixing region is good, but it cannot be said that the low temperature fixing property and the environmental dependency of the charge amount are sufficient.

In Japanese Patent Laid-Open No. 3-243958, GPC with a tetrahydrofuran content of 20% by weight or less and a soluble content of GPC
A toner having a specified molecular weight distribution and a glass transition temperature Tg of the toner has been proposed. According to this technique, the fixing region is good with a peak or shoulder in the region where the molecular weight exceeds 1,000,000, but the environmental dependence of the charging characteristics is insufficient, and there is the drawback that fogging and toner scattering occur. is there.

Japanese Unexamined Patent Publication (Kokai) No. 5-158280 proposes a toner using a styrene-based binder resin whose molecular weight distribution is specified by GPC. However, the charging characteristics are not sufficiently dependent on the environment, and the low temperature fixing property is not sufficient.

Japanese Patent Application Laid-Open No. 5-107803 proposes a toner containing a styrene-based resin, which is a styrene-based resin and has a GPC molecular weight distribution and melt viscosity specified. According to this technology, although the fixing area can be secured to some extent,
The low temperature fixing property and the charging property are not sufficiently dependent on the environment.

Japanese Unexamined Patent Publication (Kokai) No. 5-6031 proposes a toner having a vinyl-based binder resin whose molecular weight and acid value are determined by GPC. According to this technique, a toner excellent in the fixing area can be obtained, but there is a problem in the fixing property (low temperature fixing property and bending fixing property). Moreover, the environmental dependence of the charging characteristics is not satisfied.

Japanese Unexamined Patent Publication (Kokai) No. 58-86558 proposes a toner having a low molecular weight polymer and an insoluble and infusible high molecular weight polymer as main resin components, and a binder resin having a specified molecular weight distribution. This technique is also excellent in the fixing area, but has a problem in fixing property (low temperature fixing property and bending fixing property). Moreover, the environmental dependence of the charging characteristics is not satisfactory.

[0017]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned actual situation in the prior art to improve the situation. That is, the first object of the present invention is to
Secondly, to provide a toner capable of fixing at a relatively low temperature and having a wide fixing area, and particularly to provide a toner having a good bending and fixing property. Secondly, a toner having a small environmental dependence. In particular, it is to provide a toner in which the charging characteristics are less dependent on the environment.

[0018]

The above-mentioned objects of the present invention are as follows.
It is achieved by (1) or (2).

(1) In a toner containing at least a binder resin and a colorant, the binder resin has a tetrahydrofuran-insoluble content of less than 10% by weight, and the tetrahydrofuran-soluble component has a molecular weight by gel permeation chromatography. In the distribution, a low molecular weight component having a maximum value in the molecular weight of 5 × 10 ^{3 to} 5 × 10 ⁴ and a high molecular weight component having a maximum value in the 1 × 10 ^{6 to} 5 × 10 ⁶ are used, and a molecular weight of 2 × 10 ⁵ A toner for electrostatic development, characterized in that the ratio H / L of the higher molecular weight component (H) and the lower low molecular weight component (L) is 20/80 to 50/50.

(2) A binder resin comprising 5 to 40% by weight of tetrahydrofuran insoluble matter and 95 to 60% by weight of tetrahydrofuran soluble matter, wherein the tetrahydrofuran insoluble matter and gel permeation A high molecular weight component having a molecular weight of more than 2 × 10 ⁵ in a molecular weight distribution by chromatography contains 70 to 100% by weight of a styrene-based monomer component as a constituent, and a gel of the tetrahydrofuran-soluble component of the binder resin. The molecular weight in the molecular weight distribution by permeation chromatography is 2 × 10
^A low molecular weight component smaller than ⁵ contains 40 to 70% by weight of a styrenic monomer component as a constituent and 60 to 30% by weight of a monomer component represented by the following general formula [1] or [2]. The toner for electrostatic development according to (1) above, which is manufactured by using a resin.

[0021]

[Chemical 2]

The present invention will be described in detail below.

In the toner of the present invention, a low molecular weight component having a maximum value in the molecular weight of 5 × 10 ^{3 to} 5 × 10 ⁴ is fixed in the molecular weight distribution by GPC of tetrahydrofuran (THF) soluble component of the binder resin in the toner. Improve sex. Molecular weight 5 ×
If the maximum value is less than 10 ^3, the viscoelastic property during melting becomes too low, and the toner fixing area becomes narrow. In addition, since the component having a small molecular weight has low mechanical strength, the toner is excessively pulverized by stirring in the developing machine and adheres to the carrier surface,
This may reduce the charging performance of the carrier and cause fog and toner scattering. In addition, since the THF-soluble component has a maximum value in the molecular weight distribution by GPC of 1 × 10 ^{6 to} 5 × 10 ⁶ , the offset resistance is improved by this component, and the molecular weight of 2 × 10 ⁵ By setting the ratio H / L of the large high molecular weight component (H) and the low molecular weight component (L) smaller than 2 × 10 ^{5 to} 20/80 to 50/50, the low temperature fixability and offset resistance of the toner can be improved. Balance is achieved.

The THF-insoluble matter was added to the flask so that the concentration of the binder resin or the toner was 5% by weight, and the mixture was stirred with a stirrer for one day and night.
The insoluble matter and the soluble matter are separated, THF is removed by an evaporator, a vacuum dryer or the like, and the weight is measured to calculate the THF insoluble matter amount. In the case of toner, the amount of the binder resin contained in the toner is obtained and compared.

The toner of the present invention requires that the binder resin in the toner has a THF insoluble content of less than 10% by weight.
When the THF insoluble content is 10% by weight or more, the softening temperature of the toner becomes high, the adhesive force of the toner to the transfer paper becomes weak, and the low temperature fixability deteriorates. TH of binder resin in toner
The F insoluble content may be less than 10% by weight by controlling the toner kneading conditions. A roll mill, a kneader, an extruder or the like can be used for melt-kneading the toner.

The maximum molecular weight and the ratio H / L of the high molecular weight component (H) and the low molecular weight component (L) in the molecular weight distribution of the binder resin in the present invention are measured by gel permeation chromatography (GPC). can do. The molecular weight distribution by GPC is measured under the following conditions.

At a temperature of 40 ° C., the solvent (THF) is added every minute.
Flow at a flow rate of 1.2 ml, and inject 3 mg of a THF sample solution having a concentration of 0.2 g / 20 ml as a sample weight to perform measurement. When measuring the molecular weight of a sample, select the measurement conditions that fall within the range in which the logarithm of the molecular weight of the calibration curve and the count number are linear, using the monodisperse polystyrene standard samples of which the sample has several molecular weights. . The maximum molecular weight is calculated from the count number of the obtained GPC chromatogram using the calibration curve. Further, the ratio H / L of the high molecular weight component (H) and the low molecular weight component (L) is calculated from the area ratio of the portion having a molecular weight larger than 2 × 10 ⁵ and the portion having a small molecular weight.

The reliability of the measurement results is confirmed by the weight average molecular weight Mw = 28.8 × 10 ^{4 and the} number average molecular weight Mw = 13.7 × 10 ^{4 of} the NBS 706 polystyrene standard sample obtained under the above measurement conditions. be able to.

As the GPC column, any column may be adopted as long as it satisfies the above conditions. Specifically, for example, TSK-GEL, GMH (manufactured by Tosoh Corporation) or the like can be used. The solvent and measurement temperature are not limited to the described conditions, and may be changed to other appropriate conditions.

The toner of the present invention uses a binder resin made of vinyl resin. As the vinyl-based binder resin, the performance is improved by using a certain proportion of a styrene-based monomer and a specific acrylic acid ester-based monomer or vinyl ester-based monomer. That is, a THF-insoluble matter and a high-molecular-weight component having a molecular weight larger than 2 × 10 ⁵ in the molecular weight distribution by GPC have a styrene-based monomer content of 70-100.
It is preferable to use the composition in an amount of 10% by weight, and this improves the offset resistance of the toner, changes the characteristics little with respect to changes in temperature and humidity, and particularly reduces the environmental dependence of the charging property.

The THF-insoluble matter is formed by adding a polyfunctional compound such as divinylbenzene, divinylnaphthalene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, triallyl cyanurate to a styrene monomer and other vinyl monomers. By adding a monomer (crosslinking agent) and polymerizing, a crosslinked structure is introduced into the molecular structure to make it insoluble. The polyfunctional monomer is used in an amount of 3 to 25% by weight of the monomer for forming the insoluble matter. If it is less than 3%, the insoluble content is small and the offset resistance is not improved. On the other hand, 25% by weight
If it exceeds, the crosslinking reaction proceeds too much, the softening temperature of the toner rises, and the low-temperature fixability deteriorates.

As other vinyl-based monomers, it is preferable to use acrylic acid ester-based monomers, methacrylic acid ester-based monomers, and vinyl ester-based monomers,
When the monomer represented by the general formula [1] or [2] is used, the balance between the fixability and the offset resistance can be achieved.

In the invention according to claim 2, the binder resin used in the production of the toner contains 40 to 70% by weight of a styrene-based monomer as a constituent of a low molecular weight component of the THF-soluble component, The acrylic acid ester-based monomer represented by the formula [1] or the vinyl ester-based monomer represented by the general formula [2] contains 60 to 30% by weight as a monomer unit. Since these monomers have a small alkyl group in the ester portion, the affinity between the carbonyl group and the hydroxyl group in cellulose or the ester group in the polyethylene terephthalate film, which is a component of paper, becomes high, and these fixed sheets It has the effect of improving the adhesiveness with. Further, since the above-mentioned resin as the binder resin has a high ester group concentration, the cohesive force of the toner becomes high, whereby the fixability is kept good even under more severe conditions such as bending and peeling. The ratio of the THF insoluble matter and the THF soluble matter of the above resin is 5 to 40% by weight of the THF insoluble matter and the THF soluble matter.
95-60% by weight, if the ratio is in this range,
Colorants and other additives do not become non-uniform, which facilitates control of manufacturing conditions for obtaining a desired toner.
The THF insoluble content of 5 to 40% by weight in the resin is less than 10% by weight of THF in the produced toner due to the molecular chain breaking by melt-kneading in the toner production process.

What is the binder resin contained in the toner of the present invention as long as it has the maximum molecular weight and the ratio H / L of the high molecular weight component (H) and the low molecular weight component (L)? It may be obtained by a manufacturing method. Specific examples thereof include a bulk polymerization method, a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, and the like, and two or more kinds of polymerization methods may be combined for synthesis.
Among the above-mentioned polymerization methods, the solution polymerization, suspension polymerization method and emulsion polymerization method are particularly preferable from the viewpoint of easy control of the THF insoluble content and the molecular weight distribution.

The vinyl resin used as the binder resin in the present invention, a molecular weight of 2 × 10 ⁵ greater than the high molecular weight component in the molecular weight distribution by THF-insoluble matter and GPC, the 2 × 10 ⁵ less than the low molecular weight component separately First, a polymer is prepared by mixing and mixing with the first polymer
It is obtained by carrying out the second-stage polymerization by carrying out the second-stage polymerization, then dissolving it in the other monomer that gives the polymer.

The glass transition point Tg of vinyl resin is 40-80.
C., preferably 50 to 70.degree. The glass transition point can be measured by a differential scanning calorimeter (DSC). Specifically, 0 ℃
To 100 ° C., the temperature is increased to 10 ° C./min, the temperature is left for 3 minutes, and the temperature is decreased to 10 ° C./min. Then, the sample was heated again to 100 ° C at a heating rate of 10 ° C / min, and the intersection of the extension line of the baseline at that time and the tangent line showing the maximum slope from the rising part of the endothermic peak to the peak was found. The glass transition point.

The softening point Tsp of the vinyl resin is preferably 100 to 160 ° C, particularly preferably 120 to 150 ° C. The softening point is measured by a high-performance flow tester "CFT-500C" (manufactured by Shimadzu Corporation). Specifically, the diameter of the pores of the die is 1 mm,
When the length of 1 mm, the load of 20 kg / cm ² , and the heating rate of 6 ° C / min, 1 cm ³ of the sample is melted and flown out, the temperature corresponding to 1/2 of the outflow start point to the outflow end point is the softening point. And

The colorant that can be used in the toner of the present invention includes any appropriate pigment or dye. Examples of the colorant include carbon black, nigrosine dye, aniline blue, calcoil blue, chrome yellow, ultramarine blue, quinoline yellow, DuPont oil red, methylene blue chloride, phthalocyanine blue, malachite green, lamp black, rose bengal, magnetite and the like. And mixtures of these can also be used. The content of these colorants is 0 in the toner.
5 to 20% by weight is preferable.

The toner of the present invention may contain toner components such as a releasing agent, a magnetic material, a charge control agent, a fluidizing agent, and a lubricant, if necessary. As the release agent, all those conventionally used can be used. Specific examples include low molecular weight polypropylene, low molecular weight polyethylene, olefins such as ethylene-propylene copolymer, microcrystalline wax, carnauba wax, sazol wax, paraffin wax, and the like. You may use together. The addition amount of these is preferably 1 to 10% by weight in the toner. As the magnetic powder, any of those conventionally used can be used. Specifically, it is a ferromagnetic element or an alloy or compound containing them, and a compound such as magnetite, maghemite, or ferrite, a metal such as iron, cobalt, nickel, manganese, or an alloy thereof may be used. You may use magnetic powder together. The content of the magnetic powder may be 20 to 60% by weight in the toner. Examples of the charge control agent include salicylic acid derivatives and azo metal complexes. The addition amount of these is 0.01 in the toner.
It is preferable to add -10% by weight. Examples of the fluidizing agent include inorganic fine particles such as silica, titania, and alumina. Further, these inorganic fine particles are preferably hydrophobized with a silane coupling agent, a titanium coupling agent, or the like. These inorganic fine particles preferably have a number average primary particle diameter of 5 to 100 nm. The amount added is in the toner
It is preferable to add 0.01 to 10% by weight. Examples of the lubricant include metal soaps such as zinc stearate, aluminum stearate, iron stearate and copper stearate. The addition amount of these is preferably 0.01 to 10% by weight in the toner.

The toner of the present invention is mixed with a carrier and used as a two-component developer, or when it is a magnetic toner, it is used as a one-component developer only with the magnetic toner. As the carrier constituting the two-component developer, either an uncoated carrier composed only of magnetic material particles such as iron, ferrite, or magnetite, or a resin-coated carrier in which magnetic material particle surfaces are coated with a resin or the like is used. Good. The volume average particle diameter of the carrier is preferably 30 to 150 μm.

In the fixing of the toner of the present invention, the heating roller fixing device comprises a heating roller and a pressure roller, the linear pressure is 1 to 3 kg / cm, the nip width is 3 to 10 mm, and the line of the heating roller is Used at speeds of 100-400 mm / sec. Further, it is better not to have a mechanism for applying a release agent such as silicone oil, so that the structure of the fixing device can be made more compact, and oil does not stain the inside of the machine or deteriorate image quality.
When the surface layer of the heating roller is covered with a fluororesin such as polytetrafluoroethylene or perfluoroalkyl vinyl ether copolymer, the releasability becomes good.
The pressure roller is preferably made of a silicone rubber whose surface layer is coated with a perfluoroalkyl vinyl ether copolymer, or the like, from the viewpoint of fixability and image quality.

[0042]

EXAMPLES Next, the present invention will be described more specifically by way of examples.

Example 1 (1) Synthesis of Resin-Vinyl Resin-1 A separable flask of 15 liters was charged with 70 parts by weight of styrene, 30 parts by weight of methyl acrylate and 4.0 parts by weight of benzoyl peroxide, and the mixture was refluxed with toluene for 2 times. The polymerization reaction was carried out for a time. Toluene was distilled off, and the maximum molecular weight of the obtained polymer was 13,000.
Met. It is charged into a reaction vessel equipped with a distillation column, a stirrer and a thermometer, stirred at a stirring speed of 100 rpm, and distilled water 80
A solution prepared by dissolving 6.4 parts by weight of polyvinyl alcohol and 8 parts by weight of sodium sulfate in 0 parts by weight was added. Next, 210 parts by weight of the above polymer was dissolved in 75 parts by weight of styrene, 25 parts by weight of butyl methacrylate, and 5 parts by weight of divinylbenzene and charged into a reaction vessel. The stirring speed was 300 rpm, and the temperature in the vessel was 40 ° C. After stirring and mixing for an hour, 0.15 parts by weight of benzoyl peroxide was added and the temperature inside the container was raised to 90 ° C.
Suspension polymerization was carried out for 3 hours. After that, attach the Liebig cooling pipe, add the silicone antifoaming agent, and increase the temperature inside the container to 10
The temperature was raised to 0 ° C. to remove the residual monomer. Thereafter, the temperature inside the container was cooled to 90 ° C., 16 parts by weight of caustic soda was charged into the container, and the container was kept for about 30 minutes. After cooling to room temperature, the resin was taken out and dried at 50 ° C. for 24 hours in a vacuum constant temperature dryer to obtain vinyl resin-1. The obtained resin had a THF insoluble content of 35%, a softening point of 145 ° C, and a glass transition point of 65 ° C.

Vinyl resins-2 to 6 Vinyl resins-2 to 6 were obtained in the same manner as the vinyl resin-1 with the monomer composition shown in Table 1.

[0045]

[Table 1]

(2) Manufacture of toner 100 parts by weight of vinyl resin 10 parts by weight of carbon black 3 parts by weight of low molecular weight polypropylene 3 parts by weight of alkylenebis fatty acid amide 3 parts by weight The above materials are put in a V-type mixer and mixed for 20 minutes, and then mixed with a twin screw. Cylinder temperature is set to C1 = 50 ° C, C2 = 130 ° C, C3 = 1 by the automatic extruder PCM-30 (made by Ikegai Steel Works).
Melt kneading was performed at 30 ° C., CH = 130 ° C., screw rotation speed 200 rpm, and feeder rotation speed 10 rpm. After cooling, coarsely pulverize with a Wiley mill to obtain a 2 mm mesh pass product, further finely pulverize with a supersonic jet mill, and then remove fine powder with a particle size of 5 μm or less by an air classifier to obtain a volume average particle size of 9
μm colored particles were obtained.

To 100 parts by weight of the colored particles, 0.9 parts by weight of hydrophobic silica fine particles having a primary particle diameter of 13 nm and 0.05 parts by weight of zinc stearate were added, and these were mixed by a V-type mixer to prepare toner 1 of the present invention. 4 and comparative toner 1
Got 2.

(3) Preparation of Developer Each toner described above is mixed with a carrier having a volume average particle diameter of 80 μm in which magnetic particles of steel-zinc ferrite are coated with a fluororesin, and the toner concentration is 5% by weight. Each two-component developer was prepared.

(4) Evaluation Toner-insoluble matter The THF-insoluble matter was placed in a flask so that the toner concentration was 5% by weight, stirred with a stirrer for one day, and then stirred with a centrifuge for THF-insoluble matter and soluble matter. Were separated, THF was removed by an evaporator, a vacuum dryer, etc., and the weight was measured, and the amount of resin contained in the toner was determined and compared to calculate the amount of THF insoluble matter. The results are shown in Table 2.

The maximum values of the low-molecular weight component and high-molecular weight component of the THF-soluble component and the THF-soluble component were extracted from the H / L toner and measured by GPC. The measurement results are shown in Table 2.

[0051]

[Table 2]

Low-temperature fixing property of toner Electrophotographic copying machine equipped with a latent image carrier made of an organic photoconductor, a developing device for two-component developer and a heating roller fixing device, and modified so that the set temperature of the heating roller can be variably adjusted. The linear velocity of the heating roller is set to 230 mm / sec (35 cpm) with a modified machine "U-Bix 3035" (manufactured by Konica Corporation).

By changing the set temperature of the heating roller in the range of 100 to 240 ° C. in steps of 5 ° C., a solid toner chart with an original density of 1.3 is used with the above-mentioned developer, and the fixed toner image is normally adjusted so that the copy density becomes 1.3 or more. Form on paper. At this time, keep the pressure roller at 30 ° C or lower before passing the paper,
At the time of fixing, pressure is applied to form a fixed image. The end portion of the obtained fixed toner image was strongly bent with a finger, and this portion was rubbed by a rubbing tester under a constant load (100 g load) for 10 reciprocations, and then the residual rate of the image at the end portion was measured with a microdensitometer. Was measured, and the minimum set temperature (minimum fixing temperature) showing a residual rate of 80% or more was determined. The results are shown in Table 3.

Toner fixing area A fixed toner image was formed in the same manner as above except that the pressure roller was pressed against the heating roller and kept at a temperature close to the set temperature of the heating roller. Under the same conditions, send the recording material to the heating roller and visually observe whether or not toner stains occur at each set temperature of the heating roller. I asked. This temperature is shown in the column of "HO non-generated temperature" in Table 3, and the difference between this temperature and the minimum fixing temperature is shown in Table 3 as the fixing area.

The heating roller fixing device has a heating roller having a surface layer of 40 mm in diameter made of perfluoroalkyl vinyl ether copolymer and a surface layer of 40 mm in diameter made of silicone rubber coated with perfluoroalkyl vinyl ether copolymer. It has a pressure roller and
It has a linear pressure of 1.61 kg / cm, a nip width of 4.5 mm, and is not equipped with a release agent application mechanism such as silicone oil.

Dependence of toner charge amount on environment-Difference in charge amount under high temperature and high humidity and low temperature and low humidity (ΔQ / M _HL ) In a 20 ml sample tube, 1 g of each toner and magnetic particles made of copper-zinc ferrite 19g of carrier with a volume average particle size of 80μm coated with fluororesin is placed in 33 ℃, 80% RH
2 under high temperature and high humidity and under low temperature and low humidity of 10 ℃ and 20% RH
After leaving for a while, use a shaker New-Ys (manufactured by Yayoi Co., Ltd.) for 2
The mixture was mixed for 0 minutes at 200 strokes / minute, and the charge amount was measured by the blow-off method.

Decrease in charge amount after leaving in high temperature and high humidity (ΔQ /
_MH ) Into a 20 ml sample tube, 1 g of each of the above toners and 19 g of a carrier having a volume average particle diameter of 80 μm in which magnetic particles of copper-zinc ferrite are coated with a fluororesin are put, and the temperature is 33 ° C. and 80% RH
Shake machine New-Ys after left for 2 hours under high temperature and high humidity
(Manufactured by Yayoi Co., Ltd.) and the charge amount was measured by the blow-off method. Further, the charge amount after leaving this developer for 1 week in this environment was measured in the same manner, and the difference in charge amount (ΔQ / _MH ) immediately after mixing and after 1 week was determined.

The test results are shown in Table 3.

[0059]

[Table 3]

Actual copying test Using the above developer, a modified electrophotographic copying machine "U-Bix3035" (manufactured by Konica Co., Ltd.) in which the setting temperature of the fixing device is 150 ° C., the temperature is 20 ° C. and the humidity is 60% RH. 2 copy images under environmental conditions
Perform a live-action test that is repeated ten thousand times, then 33
℃, 80% RH under high temperature and high humidity 20,000 times, 10 ℃, 20% RH
Was subjected to a live-copy test of repeatedly forming 20,000 times under low temperature and low humidity, and the following items were evaluated.

The white area of the fog copy image is measured with a Macbeth densitometer,
Fog density 0.001 or less is "○", 0.001 to 0.01 is "△",
The case where it exceeds 0.01 was marked as "x".

Toner Scattering Visual observation of stains inside the machine after the actual shooting test (60,000 times) indicates that toner scatter is not recognized and is good, and “○” indicates that toner scatter is large and there is a practical problem. Was designated as "x".

Image quality The copied image was visually judged.

The test results are shown in Table 4.

[0065]

[Table 4]

It can be seen from Table 3 that the toner of the present invention is excellent in low-temperature fixability, environmental stability of fixing area and charging characteristic, and from Table 4 that the toner of the present invention has fog, toner scattering and image quality. Is also excellent.

[0067]

According to the present invention, fixing is possible at a relatively low temperature, and the fixing temperature range is wide. In particular, the adhesiveness between the fixed toner and the paper is good, and the toner at the bent portion is fixed. A toner is provided that is less likely to peel off, has less environmental dependence of charging characteristics, and has excellent fog, toner scattering, and image quality.

Claims (2)

[Claims] 1. A toner containing at least a binder resin and a colorant, wherein the binder resin has a tetrahydrofuran insoluble content of less than 10% by weight, and a tetrahydrofuran-soluble component has a molecular weight distribution by gel permeation chromatography. in the low molecular weight component having a maximum value in the molecular weight ^{5 × 10 3 ~5 × 10 4} , consists of a high molecular weight component having a maximum value at ^{1 × 10 6 ~5 × 10 6} , and from the molecular weight 2 × 10 ⁵ Large high molecular weight component (H) and small low molecular weight component (L)
And a ratio H / L of 20/80 to 50/50. 2. Tetrahydrofuran insoluble matter 5 to 40% by weight
And a tetrahydrofuran-soluble content of 95 to 60% by weight, wherein the binder resin has a tetrahydrofuran-insoluble content and a molecular weight in the molecular weight distribution by gel permeation chromatography of greater than 2 × 10 ^5. The high-molecular weight component contains 70 to 100% by weight of a styrene-based monomer component as a constituent, and the tetrahydrofuran-soluble component of the binder resin has a molecular weight of 2 × in the molecular weight distribution by gel permeation chromatography. 10 ⁵
A binder in which a smaller low molecular weight component contains 40 to 70% by weight of a styrene-based monomer component as a constituent and 60 to 30% by weight of a monomer component represented by the following general formula [1] or [2]. The toner for electrostatic development according to claim 1, which is manufactured using a resin. [Chemical 1]