JPH0544032B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an electrostatic image developing toner used for developing electrostatic latent images formed in electrophotography, electrostatic printing, electrostatic recording, etc. This invention relates to toner for developing electrostatic images. [Background of the Invention] For example, various electrophotographic methods are known (see US Pat. No. 2,297,691, etc.). Generally, an electrostatic latent image is formed by charging and exposing an electrostatic image carrier made of a photoconductive photoreceptor, and then this electrostatic latent image is transferred to a two-component developer made of toner and carrier or a magnetic material. The resulting toner image is usually transferred to an image support such as transfer paper,
This transferred toner image is then fixed by heating or pressure to form a visible image. Various methods have been used to fix toner images, and among them, a hot roller fixing method is preferred. This hot roller fixing method is a method in which the toner image is fixed on the image support by transporting the image support, such as paper, on which the toner image is carried so as to come into contact with a heated roller. This method is advantageous in terms of safety, and is also advantageous in terms of energy saving due to less heat loss. However, when a heat roller fixing method is adopted, the toner comes into contact with the surface of the heat roller in a molten state during heat roller fixation, but some of this molten toner transfers and adheres to the surface of the heat roller. However, there is a problem in that so-called offset development, in which this is transferred again to the next image support and stains the image, is likely to occur. Furthermore, in recent years, due to the demand for high-speed copying machines and miniaturization of copying machines, there has been a strong desire to develop toners that can be fixed at lower temperatures than conventional ones. That is, in a high-speed copying machine, when a large number of sheets are continuously copied, the heat of the heat roller is absorbed by the image support, and the heat cannot be replenished in time.As a result, the temperature of the heat roller decreases, which tends to cause fixing failure. In addition, in small-sized copying machines, it is necessary to reduce the capacity of the heater for heating the heat roller to make the machine more energy efficient and compact. As a result, the waiting time becomes long, or if continuous copying is performed, heat supply cannot be done in time, and as a result, the temperature of the heat roller decreases, which tends to cause fixing failure. As described above, toner for heat roller fixing is required to have (1) excellent low-temperature fixability and offset resistance in the fixing process, but in addition to these, the following conditions are also required. (2) The toner has high fluidity. This is a necessary condition to achieve good development in the development process. That is, when the fluidity of the toner is low, the adhesion of the toner to the electrostatic latent image on the latent image carrier becomes insufficient, and as a result, the density of the fixed image decreases and becomes unclear. (3) The toner has excellent filming resistance. This is a necessary condition for stably forming good images over many times. That is,
If the toner has poor filming resistance, as the image forming process is repeated, the toner material will gradually accumulate on the surface of the latent image carrier or carrier, resulting in damage to the latent image carrier or carrier. This impairs the characteristics and makes it difficult to perform a stable image forming process. [Prior Art] Conventionally, the following technical means are known. (b) Technical means of using a polymer formed by chemically linking a crystalline polymer with a melting point of 45 to 150°C and an amorphous polymer with a glass transition point of 0°C or less as a resin for toner (Unexamined Japanese Patent Publication No. (Refer to Publication No. 1987-87032). (b) As a toner resin, a thermoplastic containing in its molecules a crystalline polymer with a melting point of 45 to 90°C and an amorphous polymer with a glass transition point higher than the melting point of the crystalline polymer by 10°C or more. A technical means using a polymer in which the content of crystalline polymer in the polymer is 70 to 95% by weight (see JP-A-59-3446). (c) Technical means of forming a toner using a polyester resin containing 5% by weight or more of chloroform-insoluble matter and wax containing 20% by weight or more of an ester component and having a penetration of 4 or less (Patent Application No. 1983) −
See specification No. 38843. ). [Problems to be Solved by the Invention] However, the technical means (a) to (c) above have the following problems. Although the technical means (a) above has good low-temperature fixing properties, it has problems with poor offset resistance, crushability, and filming resistance. That is, the toner resin is a crystalline polymer that is soft at room temperature due to its melting point of 45 to 150°C, and a glass transition point of 0.
Because it is a copolymer chemically bonded with an amorphous polymer that is sticky and soft at room temperature due to the temperature below ℃, the toner has high stickiness and therefore does not have an oil supply mechanism. A hot roller fixing device has a problem in that an offset phenomenon tends to occur. Furthermore, since the toner has high tackiness, the toner tends to aggregate in the developing device, etc., resulting in a problem in that the fluidity of the developer is low and, as a result, the image becomes unclear. Furthermore, due to multiple copies, a so-called toner filming phenomenon occurs in which the soft toner resin is transferred and adhered to the surface of the photoreceptor or carrier particles, resulting in a problem of low density and unclear images. In addition, since the toner resin is soft, the toner tends to form lumps in the pulverizer when pulverized at room temperature during the pulverization process, which is one of the normal toner manufacturing processes, making it difficult to pulverize the desired product. However, there is a problem that a toner with a particle size of In addition, the technical means in (b) above is effective when applied to image formation using a transfer process using an intermediate transfer body, and is effective when applied to image formation using a fixing process using a heat roller fixing method. In this method, the elasticity of the toner is low when it is heated and melted by a heat roller, and therefore, a portion of the toner is transferred to the heat roller during fixing, which tends to cause an offset phenomenon. In other words, in forming the toner resin, an amorphous polymer with a high glass transition point is used, so in order to obtain sufficient low-temperature fixing properties, the proportion of crystalline polymer used must be as high as 70 to 95% by weight. As a result, the properties of the soft crystalline polymer, which has plastic deformability at room temperature, are reflected in the toner, and as a result, it is possible to fix the toner by heating it in a short time, such as with a heated roller fixing device that does not apply a large amount of oil. In this method, the fixing temperature becomes high and offset phenomenon tends to occur. Also, since the toner resin is soft,
There is a problem that the fluidity of the toner is low, resulting in an unclear image. Furthermore, when image formation is performed multiple times, a so-called toner filming phenomenon occurs in which the toner resin transfers and adheres to the surface of the photoreceptor or carrier particles, resulting in a problem of low density and unclear images. be. In addition, although the above technical means (c) can be said to have sufficient offset resistance, low-temperature fixing properties are still insufficient, resulting in poor fixing, especially when used as toner for high-speed copying machines or small-sized copying machines. There are some easy problems. As described above, when subjected to high-speed fixing, it fully satisfies low-temperature fixing properties and offset resistance, and also satisfies fluidity and filming resistance, and has good pulverization properties in the toner manufacturing process. The reality is that toner for hot roller fixing has not yet been obtained. [Object of the Invention] The present invention has been made based on the above-mentioned circumstances, and its objects are (1) to have excellent low-temperature fixing properties, (2) to have excellent offset resistance, (3) It must have high fluidity, (4) It must have excellent filming resistance, and (5) It must have good crushability and be able to obtain toner with a small diameter through a normal crushing process. An object of the present invention is to provide a satisfactory electrostatic image developing toner for heat roller fixing. [Means for Solving the Problems] The electrostatic image developing toner for heat roller fixing of the present invention contains (a) 40 to 90% by weight of a low melting point crystalline aliphatic polyester having a melting point of 50 to 100°C; (b) A resin consisting of a block copolymer or a graft copolymer formed by chemically bonding 10 to 60% by weight of at least two kinds of crystalline polyesters having a melting point of 170 to 230°C; 0.5 to 20 parts by weight of a mold release agent having a penetration of 4 or less per 100 parts by weight of the resin, and each of the two types of crystalline polyesters has a weight average molecular weight of 3000 to 50000, The number average molecular weight is
1000 to 20000, and the weight average molecular weight of the resin is 5000 to 100000,
The number average molecular weight is 2000 to 50000, the dynamic elastic modulus at 100℃ is 1.0×10 ⁴ dyne/cm ² or more, and the melt viscosity is
It is characterized by less than 5.0×10 ⁴ poise. [Operations and Effects of the Invention] According to the toner of the present invention, the copolymer contained is 40 to 90% by weight of a low melting point crystalline aliphatic polyester having a melting point of 50 to 100°C and a melting point of 170 to 230°C. Since it is a block copolymer or graft copolymer formed by chemically bonding at least two types of crystalline polyester with 10 to 60% by weight of a high melting point crystalline polyester, the copolymer has a high melting point. The toner has a structure in which the segment and the low melting point segment are connected, and the toner stably exhibits both the excellent properties based on the high melting point segment and the excellent properties based on the low melting point segment. In the fixing process, excellent low temperature fixing properties and excellent offset resistance are obtained. That is, during fixing, when the toner is heated to a temperature higher than the melting point of the low melting point segment and the low melting point segment melts, the toner particle is in a highly fluid state within the particle, but the high melting point segment causes the toner particle to melt. As a result, the toner particles do not flow suddenly and are kept in a highly elastic state.As a result, the transfer of the toner to the heated roller is suppressed, and the toner is fixed at a low temperature. will be done. While the copolymer described above has poor crushability due to the soft characteristics of crystalline polyester, the toner of the present invention has a penetration degree of 4.
The following mold release agent is contained, and since the mold release agent has relatively hard physical properties, the presence of this mold release agent suppresses the development of the soft characteristics of crystalline polyester, and as a result, the production of toner In the crushing step, which is one of the steps, toner having a sufficiently small diameter can be easily obtained, and as a result, toner can be manufactured efficiently. In addition, the presence of the release agent suppresses the soft characteristics of the crystalline polyester and provides high slip properties, so the toner has high fluidity and can perform a good development process. Transfer and adhesion of the toner substance to the surface of the latent image carrier or transfer and adhesion to the carrier surface is less likely to occur, and excellent filming resistance can be obtained. [Specific Structure of the Invention] The present invention will be described in detail below. The electrostatic image developing toner for heat roller fixing of the present invention contains 40 to 90% by weight of a low melting point crystalline aliphatic polyester with a melting point of 50 to 100°C, and a high melting point polyester with a melting point of 170 to 230°C as essential components. Melting point of crystalline polyester 10
-60% by weight of a block copolymer or graft copolymer formed by chemically bonding at least two types of crystalline polyesters, and 0.5 to 20 parts by weight per 100 parts by weight of this resin. A mold release agent having a penetration degree of 4 or less is contained. The crystalline polyesters used to form the block copolymer or graft copolymer are at least two types having different melting points, and among them,
Low melting point crystalline aliphatic polyester has a low melting point.
Its melting point Tmp is 50-100°C, preferably 50-80°C. In addition, high melting point crystalline polyester has a melting point Tmp of 170 to 230℃.
and preferably 180 to 230°C, especially
The temperature is preferably 200 to 230°C. When the melting point Tmp of each crystalline polyester is too low, toner particles tend to aggregate and the fluidity as a powder decreases. On the other hand, when the melting point Tmp of each crystalline polyester is too high, low-temperature fixing properties may deteriorate. In addition, the melting point of low melting point crystalline aliphatic polyester
If the difference between Tmp and the melting point Tmp of the high melting point crystalline polyester is too small, that is, the difference in melting point Tmp between the crystalline polyesters used in forming the block copolymer or graft copolymer is too small. In some cases, it becomes difficult to obtain a toner that has both sufficient low-temperature fixability and sufficient offset resistance. i.e. melting point
When the difference in Tmp is small, the melting point of the crystalline polyester used will tend to be lower or higher overall, and as a result, even if the low temperature fixability is sufficient, the offset resistance will decrease, or Even if the offset resistance is sufficient, the low-temperature fixability may deteriorate. In the block copolymer or graft copolymer, the proportion of the low melting point crystalline aliphatic polyester in the crystalline polyester that is the constituent unit of the copolymer is 40 to 90% by weight, and 50 to 70% by weight. Preferably, it is % by weight. If the proportion of this low melting point crystalline aliphatic polyester is too small, the low temperature fixing properties may be insufficient, while if it is too large, the offset resistance may be insufficient. In addition, in the block copolymer or graft copolymer, the proportion of high melting point crystalline polyester in the copolymer is 10 to 60% by weight, and 30 to 50% by weight of the crystalline polyester that is the constituent unit of the block copolymer or graft copolymer. Preferably, it is % by weight. If the proportion of this high melting point crystalline polyester is too small, offset resistance may be insufficient, while if it is too large, low temperature fixing properties may be insufficient. The crystalline polyester used for forming the block copolymer or graft copolymer has a weight average molecular weight Mw of 3,000 to 50,000 and a number average molecular weight Mn of 1,000 to 20,000. By using a crystalline polyester having such a molecular weight, the toner has even better low-temperature fixability and offset resistance. The weight average molecular weight Mw of the block copolymer or graft copolymer is preferably 5,000 to 100,000, particularly preferably 10,000 to 50,000.
In addition, the copolymer has a number average molecular weight Mn of
2000 to 50000, preferably 3000 to 15000. By selecting a copolymer having such a preferable molecular weight, the toner can have even better offset resistance and low-temperature fixing properties. The block copolymer or graft copolymer has a dynamic elastic modulus G' of 1.0× at a temperature of 100°C.
10 ⁴ dyn/cm ² or more, and the melt viscosity at a temperature of 100°C is 5.0×10 ⁴ poise or less. By using a copolymer having such a dynamic elastic modulus G' and melt viscosity, it is possible to further improve the offset resistance and low-temperature fixing properties of the toner. The block copolymer or graft copolymer preferably has a softening point Tsp of 80 to 130°C, particularly preferably 90 to 110°C.
By using a copolymer having such a preferable softening point Tsp, the offset resistance of the toner can be improved.
Low-temperature fixing properties and filming resistance become even more excellent. The crystalline polyester used to form the block copolymer or graft copolymer is a polymer in which at least a part of the crystalline polyester has a crystal structure, and at least one component in the homopolymer or copolymer is crystalline. In other words, it shows a sharp and clear melting point Tmp, even if it is partially crystalline.
In the solid state at the following temperatures, clouding occurs due to crystallized portions. The fact that it is a crystalline polyester can be confirmed, for example, by measuring the X-ray diffraction intensity. Specifically, in the X-ray diffraction intensity curve, the diffraction intensity of the crystalline portion decreases as the temperature rises, and the melting point Tmp It can be confirmed by disappearing nearby. In forming the block copolymer or graft copolymer, a low melting point crystalline aliphatic polyester with a melting point of 50 to 100°C and a melting point of 170 to 230°C are used.
with a high melting point crystalline polyester of at least 2
Although it is necessary to use a seed crystalline polyester, other crystalline polyesters having a melting point Tmp of 45° C. or higher may also be used if necessary. Therefore, the block copolymer or graft copolymer may be formed from three or more types of crystalline polyesters. The low melting point crystalline aliphatic polyester used to form the block copolymer or graft copolymer can be selected from aliphatic polyesters having a melting point of 50 to 100°C. Further, the high melting point crystalline polyester can be selected from, for example, aliphatic polyesters and aromatic polyesters having a melting point of 170 to 230°C. In addition, polyesters having reactive groups such as hydroxyl groups, amino groups, carboxyl groups, mercapto groups, halogens, etc. that can be chemically bonded to coupling agents at the terminals of these polyesters can also be preferably used. Polyesters can be block copolymerized or graft copolymerized using coupling agents. Specific examples of such crystalline polyesters include, but are not limited to, those listed below. Polydecamethylene adipate, polydecamethylene azelate, polydecamethylene oxalate,
Polydecamethylene sebacate, polydecamethylene succinate, polyethylene sebacate, polyethylene suberate, polyethylene succinate,
Polyhexamethylene sebacate, polyhexamethylene suberate, polyhexamethylene oxalate, polyhexamethylene succinate, poly-10
-Hydroxycaprylic acid, poly-6-hydroxycaproic acid, poly-3-hydroxypropionic acid. The copolymer contained in the toner of the present invention is a block copolymer or a graft copolymer formed by chemically bonding at least two or more specific crystalline polyesters. An example of a specific means for obtaining the copolymer is, for example, by coupling the terminal functional groups present in each crystalline polyester to each other directly in a head-to-tail manner to obtain the copolymer. I can do it. In another example, it can be bonded to the terminal functional group of each crystalline polyester using at least a difunctional coupling agent. Specifically, for example, a urethane bond formed by a reaction between a crystalline polyester whose terminal group is a hydroxyl group and a diisocyanate, and a urethane bond formed by a reaction between a crystalline polyester whose terminal group is a hydroxyl group and a dicarboxylic acid, for example. For example, an ester bond formed by the reaction of a crystalline polyester whose terminal group is a carboxyl group with a glycol; for example, a reaction between a crystalline polyester whose terminal group is a hydroxyl group and phosgene, dichlorodimethylsilane, etc. A copolymer can be obtained by a bond such as a bond formed by the above. Coupling agents that can be used to form such copolymers include, for example, polyfunctional isocyanates, polyfunctional amines, polyfunctional carboxylic acids,
Examples include polyfunctional alcohols and polyfunctional acid chlorides. As this coupling agent,
It is preferable to select a coupling agent that reacts with the crystalline polyester but does not react with itself. Specific examples of such coupling agents include hexamethylene diisocyanate, diphenylmethane diisocyanate, tolylene diisocyanate, toridine diisocyanate, naphthylene diisocyanate, isophorone diisocyanate,
Difunctional isocyanates such as xylylene diisocyanate; difunctional amines such as ethylene diamine, hexamethylene diamine, phenylene diamine; difunctional amines such as oxalic acid, succinic acid, adipic acid, sebacic acid, terephthalic acid, isophthalic acid, etc. Carboxylic acids; e.g. ethylene glycol, propylene glycol, hexanediol,
Difunctional alcohols such as cyclohexanedimethanol and p-xylylene glycol; difunctional acid chlorides such as terephthalic chloride, isophthalic chloride, adipic chloride, and sebacic chloride; such as diisothiocyanate, bisketene, bis Other difunctional coupling agents such as carbodiimides; e.g. triphenylmethane triisocyanate, 1,3,6-hexathimethylene triisocyanate, 1,6,11-undecane triisocyanate, tris(isocyanate phenyl) thiophosulfate; tri- or higher-functional polyfunctional isocyanates such as ate; for example, triaminobenzene,
Tri- or higher-functional polyfunctional amines such as triaminotoluene and triaminotriphenylmethane; for example, 1,2,4-benzenetricarboxylic acid, 1,2,
5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2, 5-hexanetricarboxylic acid, 1,
3-dicarboxyl-2-methyl-2-methylenecarboxylpropane, tetra(methylenecarboxyl)methane, 1,2,7,8-octanetetracarboxylic acid, Empol trimer acid, and acid anhydrides thereof, etc. Functional or higher polyfunctional carboxylic acids; for example, sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1,2,4- Butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethyl Trifunctional or higher polyfunctional alcohols such as benzene; etc. can be mentioned. These coupling agents can be used alone or in combination of two or more. In addition, when using a combination of a bifunctional coupling agent and a trifunctional or higher functional coupling agent,
A coupling agent containing a trifunctional or more functional coupling agent in an amount of 0 to 30 mol % based on the total coupling agent is preferred. The ratio of the copolymer to the toner is 70 to 95
% by weight, especially 80-90% by weight
It is preferable that If the content of the copolymer is too small, low-temperature fixing properties and offset resistance may deteriorate. In the present invention, melting point Tmp, glass transition point
Tg, weight average molecular weight Mw and number average molecular weight
Mn, dynamic elastic modulus G', melt viscosity, and softening point Tsp are each defined as values measured as follows. <Melting point Tmp> According to differential scanning calorimetry (DSC), the number of samples
The melting point is the intersection of the slope of the melting peak and the baseline when the sample is heated at a constant temperature increase rate (10°C/min). <Glass transition point Tg> It can be measured according to differential scanning calorimetry (DSC) using, for example, "DSC-20" (manufactured by Seiko Electronics Co., Ltd.); specifically, approximately 10 mg of sample
is heated at a constant temperature increase rate (10°C/min), and the glass transition point Tg is obtained from the intersection of the baseline and the slope of the endothermic peak. <Weight-average molecular weight Mw and number-average molecular weight Mn> The values of weight-average molecular weight Mw and number-average molecular weight Mn can be determined by various methods, and there are slight differences depending on the measurement method. , it is defined as that determined according to the measurement method below. That is, the weight average molecular weight Mw and number average molecular weight Mn are measured by gel permeation chromatography (GPC) under the conditions described below. At a temperature of 40℃, the solvent (tetrahydrofuran) was flowed at a flow rate of 1.2ml per minute, and the concentration was 0.2g/min.
Measurement is performed by injecting 20 ml of tetrahydrofuran sample solution to a sample weight of 3 mg. When measuring the molecular weight of a sample, the measurement conditions are such that the molecular weight of the sample falls within the range where the logarithm of the molecular weight and the count number of a calibration curve prepared using several types of monodisperse polystyrene standard samples are linear. select. The reliability of the measurement results can be confirmed by the fact that the weight average molecular weight Mw = 28.8 x 10 ⁴ and the number average molecular weight Mn = 13.7 x 10 ⁴ for the NBS706 polystyrene standard sample measured under the above measurement conditions. Moreover, any column may be used as the GPC column as long as it satisfies the above conditions. Specifically, for example, TSK-
GEL, GMH ₆ (manufactured by Toyo Soda Co., Ltd.), etc. can be used. Note that the solvent and measurement temperature are not limited to the conditions described, and may be changed to appropriate conditions. <Dynamic elastic modulus G', melt viscosity> Melt the sample at a certain temperature, apply sinusoidal vibration to the sample in the molten state, and obtain the dynamic elastic modulus and melt viscosity from the torsion amplitude ratio and phase difference. . <Softening point Tsp> Using a flow tester "CFT-500" (manufactured by Shimadzu Corporation), the measurement conditions were: load 20Kg/cm ² , nozzle diameter 1mm, nozzle length 1mm, preheating time 50℃
for 10 minutes at a heating rate of 6°C/min, and the sample amount
When measuring and recording 1.0 cm ³ (weight expressed as true specific gravity x 1 cm ³ ), when the height of the S-curve in the plunger drop-temperature curve (softening flow curve) of the flow tester is h, h/2 The temperature at which this occurs is defined as the softening point TSP. In addition to the block copolymer or graft copolymer, the toner of the present invention contains a release agent having a penetration of 4 or less as a second essential component. In the present invention, the penetration degree of a mold release agent is defined as a value measured as follows. <Penetration> Penetration is measured in accordance with the test method specified in JIS K2235-1980. Specifically, the sample was heated and melted, placed in a sample container, left to cool, and then kept at a constant temperature of 25°C in a constant temperature water bath, and the total mass was calculated.
Insert a needle weighing 100 g vertically into the sample for 5 seconds, measure the depth of penetration to the nearest 0.1 mm, and multiply this by 10 to determine the degree of penetration. The penetration degree of the release agent must be 4 or less, and when the penetration degree exceeds 4, the release agent is soft, so the fluidity and filming resistance of the toner decrease, Furthermore, in the toner manufacturing process, the crushability deteriorates, making it difficult to obtain toner with a small diameter. Furthermore, the mold release agent has a melting point Tmp of 50 to 120.
It is preferable that it is ℃. By selecting a mold release agent having such a preferable melting point Tmp,
The toner has better low-temperature fixing properties, offset resistance, filming resistance, and fluidity. If the melting point Tmp is too small, the toner's offset resistance, filming resistance, and fluidity may be reduced, while if it is too large, the toner's low-temperature fixability may be reduced. Furthermore, the proportion of the release agent is 0.5 to 20% by weight, preferably 1 to 10% by weight, based on the toner. By setting such a preferable ratio, the effect of the mold release agent can be fully exhibited without inhibiting the development of the excellent properties of the block copolymer or graft copolymer. If the proportion of the release agent is too small, the offset resistance and low-temperature fixing properties of the toner may be reduced, and the pulverization properties may be deteriorated in the toner manufacturing process. On the other hand, if the ratio is excessive, the filming resistance and fluidity of the toner may deteriorate. Specific examples of the mold release agent include, for example, No. 1 below.
Examples include, but are not limited to, those shown in the table.

【table】

[Specific examples]

Hereinafter, specific examples and comparative examples of the present invention will be described, but the present invention is not limited to these examples. The specific compositions of the crystalline polyesters used in the following Examples and Comparative Examples are as shown in Table 2 below, and in each Example and Comparative Examples, the combinations of crystalline polyesters shown in Table 3 below were used. and a copolymer synthesized at a blending ratio and a mold release agent shown in Table 4 below. <Examples 1 to 9 and Comparative Examples 1 to 6> In each of the Examples and Comparative Examples, a resin, a mold release agent, and a mold release agent were used in the combinations and proportions shown in Table 5 below.
After mixing with the coloring agent and pre-dispersing it, it is melt-kneaded using heating rolls, and after cooling, it is subjected to a jet mill (pressure:
6.5Kg/cm ² ) and then classified to obtain a toner having a weight average particle size of 11 μm. The toners obtained in Examples 1 to 9 and Comparative Examples 1 to 6 are referred to as "Toner 1" to "Toner 9" and "Comparative Toner 1" to "Comparative Toner 6," respectively. The crushability of each toner obtained as described above is also shown in Table 6 below. The crushability was evaluated as follows. Grindability Calculate the yield of the obtained toner with respect to the toner raw materials input into the grinding process. If the yield is 95% or more, it is marked "○", and if the yield is less than 95% but 85% or more, it is marked "△". ", and cases where the yield was less than 85% were marked "×". <Actual photo test> Next, 5 parts by weight of each of Toners 1 to 9 and Comparative Toners 1 to 6 were mixed with 95% of a resin-coated carrier coated with styrene-acrylic resin and having an average particle diameter of 80 μm.
A total of 15 types of developers were prepared by mixing parts by weight. Using these developers, an electrostatic latent image was formed and developed using an electrophotographic copying machine "U-Bix 1600" (manufactured by Konishiroku Photo Industries Co., Ltd.), and the resulting toner image was transferred onto transfer paper. A live copying test was conducted in which a copy image was formed by fixing with a heat roller fixing device, and the minimum fixing temperature (the lowest temperature of the heat roller that can be fixed) and offset occurrence temperature (the lowest temperature at which offset development occurs) were measured using the following method. . Minimum fixing temperature After creating an unfixed image with a copying machine, a 30φ heat roller whose surface layer is made of Teflon (polytetrafluoroethylene manufactured by Dupont) and a silicone rubber surface layer "KE-1300RTV" (Shin-Etsu Chemical Co., Ltd.) are used. A toner image made of the sample toner was transferred onto a 64 g/ ^m2 transfer paper using a heat roller fixing device consisting of a pressure roller (manufactured by
Fusing operation at 70mm/sec, linear pressure 0.8Kg/cm, nip width 4.9mm, heat roller set temperature 80-230.
The fixed image formed by increasing the temperature in steps of 5°C and repeating it at each temperature within the range of 5°C.
Rubbing was performed using the same paper as the transfer paper using a hardness tester, and the lowest set temperature for a fixed image that showed sufficient scratch resistance was defined as the lowest fixing temperature. Note that the heat roller fixing device used here does not have a silicone oil supply mechanism. Offset Occurrence Temperature The offset occurrence temperature is measured in accordance with the above-mentioned minimum fixing temperature measurement, but after creating an unfixed image with a copying machine, the toner image is transferred and fixed using the above-mentioned heat roller fixing device. Next, a blank transfer paper is sent to the heat roller fixing device under the same conditions, and visually observing whether or not toner stains occur on it is carried out by sequentially increasing the set temperature of the heat roller of the heat roller fixing device. The temperature was repeated in this state, and the lowest set temperature at which toner staining occurred was taken as the offset occurrence temperature. The above results are also shown in Table 6 below. Further, the blocking resistance and filming resistance of each toner and the fluidity of each developer were measured as follows. Blocking Resistance The toner is left under the environmental conditions of 50°C and 33% relative humidity for 2 hours, and judged by whether or not agglomerates form in the toner. If no agglomerates are observed, it is evaluated as "``○'', cases in which some aggregates were observed were rated ``△'', and cases in which a considerable amount of aggregates were observed were rated "x". Filming resistance After 20,000 live-action tests, the photoconductor surface and carrier particle surface were observed and judged based on the presence or absence of deposits on the surfaces.If no deposits were observed, it was marked as "○". A case where a slight amount of deposits was observed was marked as "△", and a case where a considerable amount of deposits was observed was marked as "x". Fluidity of developer The developer in the developing device was visually observed during the initial stage of image formation and after 20,000 times of image formation, and those with good fluidity were marked as "○", and although it could not be said to be good, it was at a practical level. Items with a certain value were marked with a ``△'', and items with practical problems were marked with an ``x''. The above results are also shown in Table 6. Further, for the copied images obtained using each developer, the image density at the initial stage of copying and the image density after 20,000 times of copying were measured as follows. Image Density Using a "Sakura Densitometer" (manufactured by Konishiroku Photo Industry Co., Ltd.), the density of the copied image was measured with respect to the original image's density of 1.30, and the average value of the 10 copied images was taken as the image density. The above results are also shown in Table 6.

【table】

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[Table] As understood from the results in Table 6, toners 1 to 9 of the present invention all have (1) excellent low-temperature fixing properties, and (2) excellent offset resistance. (3) have high fluidity; (4) have excellent filming resistance; and (5) have good crushability and can obtain small-diameter toner through a normal crushing process. It satisfies the following conditions. On the other hand, according to Comparative Toners 1 and 4, since they do not contain a release agent, they have poor crushability and low toner production efficiency, and also have poor low-temperature fixing properties.
The offset resistance and filming resistance were poor, and after 20,000 times of printing, the fluidity of the developer was significantly reduced, and the resulting copied images were unclear with low image density. According to Comparative Toners 2, 3, 5, and 6, the penetration degree of the release agent exceeds 4, so the crushability is poor and the toner production efficiency is low, and the fluidity of the developer is poor. The resulting copied image had a low image density from the initial stage of image formation, and after 20,000 times of image formation, the image density further decreased significantly and the filming resistance was also poor.

Claims (1)

[Scope of Claims] 1. (a) 40 to 90% by weight of a low melting point crystalline aliphatic polyester having a melting point of 50 to 100°C, and (b) 10 to 60% by weight of a high melting point crystalline polyester having a melting point of 170 to 230°C. % by weight of a block copolymer or graft copolymer formed by chemically bonding at least two types of crystalline polyesters, and a resin having a penetration of 0.5 to 20 parts by weight per 100 parts by weight of this resin. 4 or less, and each of the two types of crystalline polyesters has a weight average molecular weight of 3,000 to 50,000 and a number average molecular weight of
1000 to 20000, and the weight average molecular weight of the resin is 5000 to 100000,
The number average molecular weight is 2000 to 50000, the dynamic elastic modulus at 100℃ is 1.0×10 ⁴ dyne/cm ² or more, and the melt viscosity is
An electrostatic image developing toner for heat roller fixing, characterized by having a toner of 5.0×10 ⁴ poise or less.