JPH0544030B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention is a developer for developing electrostatic images formed in electrophotography, electrostatic printing, electrostatic recording, etc. The present invention relates to a heat roller fixing electrostatic image developing toner that is fixed by a roller. [Technical background] Various electrophotographic methods have been known in the past, including the method disclosed in U.S. Pat. An electrostatic latent image is formed, and this electrostatic latent image is developed with a two-component developer consisting of toner and carrier or a single-component developer consisting of toner containing a magnetic material, and the formed toner image is printed on a sheet such as paper. A method has been adopted in which the visible image is permanently fixed by heating, applying pressure, etc. Although various methods have been adopted for fixing toner images on sheets such as paper, a heat roller fixing method in which a toner image is fixed using a heat roller is particularly widely used. The heated roller fixing method is a method in which the sheet carrying the toner image is passed through contact with a heated roller, thereby fixing the toner image onto the sheet, resulting in low heat loss, safety, and energy saving. This is advantageous from the point of view. However, in such a heat roller fixing method, when conventional toner is used, the toner in the toner image becomes molten when it comes into contact with the heat roller surface, so a part of the toner image is on the fixing roller surface. There is a problem in that the so-called offset phenomenon occurs in which the toner adheres to and transfers to the fixing sheet, which is then transferred, and stains the image. Such an offset phenomenon is likely to occur when a low molecular weight resin is used as the binder resin of the toner, as described in Japanese Patent Publication No. 51-23354. As a countermeasure to this offset phenomenon, it is conceivable to use a resin with a high degree of polymerization and therefore a large molecular weight as a binder resin for the toner, but according to the studies of the present inventors, this alone does not necessarily provide good offset resistance. It has been found that in some cases, the result is only an increase in the fixing temperature. Therefore, as described in JP-A-50-134652, a constant molecular weight polymer and a high molecular weight polymer are blended to create a resin with an appropriate molecular weight distribution.
Attempts have been made to produce toners that prevent increases in fixing temperature and have good offset resistance by using this as a binder resin, but in this case, offset resistance cannot be sufficiently improved. Alternatively, if you try to lower the fixing temperature, the blocking resistance of the toner deteriorates, leading to toner agglomeration in the developing device, or toner filming, where toner components adhere to carrier particles and the surface of the photoreceptor. . Furthermore, as described in JP-A No. 51-23354, it is possible to use a crosslinked resin as a binder resin for toner; It has been found that using only a resin does not necessarily yield good results. In other words, increasing the degree of crosslinking of the binder resin is effective in preventing toner offset;
At the same time, the minimum fixing temperature required for fixing becomes high. On the other hand, if the degree of cross-linking of the binder resin is low, although the minimum fixing temperature of the toner can be maintained low, the offset resistance will be insufficient. It is not possible to obtain a wide fixable temperature range defined as the range, and furthermore, the blocking resistance of the toner deteriorates, making it impossible to obtain a good image. In addition, in order to prevent the occurrence of offset phenomenon,
For example, the roller surface is made of a material such as silicone rubber or fluororesin that has excellent releasability for toner, and the roller surface is also made of a material such as silicone oil to prevent offset and fatigue of the roller surface. Apply mold release oil to the surface of the roller,
There is a method of coating the roller surface with the thin film. However, although this method is effective in preventing the offset phenomenon, it requires a device to supply mold release oil, making the fixing device complicated and causing the mold release oil to evaporate due to heating. This has problems such as giving off an unpleasant odor to the user. This method does not essentially solve the problem of offset phenomenon. Therefore, it is desired to develop a toner for developing electrostatic images which has characteristics that do not easily cause the offset phenomenon and which has a wide fixing temperature range. Particularly in recent years, due to demands for higher copying speeds and energy savings, there has been a strong desire to develop toners that can be fixed at lower temperatures than conventional ones. In other words, when a high-speed copying machine performs a large number of continuous copies, the heat of the heat roller is absorbed by the image-receiving sheet and the temperature of the heat roller decreases, which causes the temperature to drop below the minimum fixing temperature of the toner, resulting in defective fixing. . Additionally, if the capacity of the heater for heating the heat roller is reduced in order to save energy, the surface temperature of the heat roller will not be able to rise to the temperature required for fixing the toner, resulting in poor fixing. . As described above, recently, toners for developing electrostatic images must meet the difficult requirements of lowering the minimum fixing temperature and widening the fixable temperature range while maintaining offset resistance. Furthermore, in order to lower the fixing temperature of the resulting toner, when a binder resin with a low softening point is used, or when a resin whose softening point is lowered by adding a low molecular weight plasticizer is used, Not only does the toner's offset resistance deteriorate, but its glass transition temperature also decreases, so if the toner is left in a heated atmosphere inside a copying machine or at a relatively high temperature outside the machine, toner particles will be able to bond with each other. Blocking occurs when the toner adheres and aggregates, forming lumps, rendering it useless as a toner. In particular, in the case of toners made of styrene-acrylic copolymers, polyester resins, epoxy resins, etc., which are currently widely used as binder resins for toners, blocking occurs when the glass transition temperature is below 40°C. The occurrence becomes noticeable. Even when a resin whose softening point is simply lowered in this way is used, it is not possible to simultaneously satisfy the three properties of offset resistance, low temperature fixing property, and blocking resistance. Also, of course, toner has fixability,
In addition to offset resistance and blocking resistance, it is also necessary to have excellent developability, triboelectric charging properties, transferability, cleaning properties, fluidity, etc.
Conventional toners have at least one of the following defects:
It is pointed out that there are more than one. That is, in many cases, in order to obtain a toner with a low minimum fixing temperature, the softening point is lowered by adding a resin with a low softening point or a plasticizer having a melting point lower than the softening point of the resin. When a toner is used as a binder resin, the binder resin has a lowered glass transition point, resulting in poor toner offset resistance and blocking resistance, and poor triboelectric charging properties. Problems such as a decrease in image density and an increase in fog occur, and as a result, it becomes impossible to obtain a good image. Furthermore, in order to achieve fixing at low temperatures, when a resin plasticized with a plasticizer made of a soft, low molecular weight compound with a low melting point such as wax is used as a binder resin, the fluidity of the toner often deteriorates. This makes it difficult to supply toner within the electrophotographic copying machine, and developability deteriorates, making it impossible to obtain good images. In addition, when continuous copying is performed, a filming phenomenon occurs in which soft plasticizers and the like adhere to the carrier particles and the surface of the photoreceptor due to collision with carrier particles and contact with the photoreceptor, resulting in poor triboelectrification and developability. becomes defective and a good image cannot be obtained. [Object of the Invention] An object of the present invention is to provide an electrostatic image developing toner for heat roller fixation, which has a low minimum fixing temperature, good offset resistance, and good blocking resistance. Another object of the present invention is to provide an electrostatic image developing toner for hot roller fixation that has excellent fluidity, does not cause filming on carrier particles or the surface of a photoreceptor, and has excellent durability. Still another object of the present invention is to provide an electrostatic image developing toner for heat roller fixing, which provides a clear image with high image density and little fog. [Structure of the Invention] The object of the present invention is to (a) have a melting point of 50 to 95°C, a penetration of 5.0 or less, a weight average molecular weight of 3000 to 20000, and a number average molecular weight of 1000.
~15000, 5-40 for the entire binder resin
% by weight of crystalline polyester, and (b) from (1) styrenic monomers, (2) acrylic esters and/or methacrylic esters, and (3) aromatic vinyl compounds, acrylic esters, and methacrylic esters. A nonlinear styrene-acrylic system having a softening point of 100 to 150°C, a glass transition point of 40 to 80°C, and a penetration of 1.0 or less, obtained by polymerizing monomers having two or more selected vinyl groups. It contains a binder resin consisting of a copolymer and a polyolefin having a softening point of 110 to 150°C, wherein the melting point of the crystalline polyester (a) is equal to the softening point of the nonlinear styrene-acrylic copolymer (b). point, the crystalline polyester (a) and the nonlinear styrene-acrylic copolymer (b) are incompatible with each other, and the crystalline polyester (a) is lower than the nonlinear styrene-acrylic copolymer (b). This is achieved by an electrostatic image developing toner for heat roller fixing, which is characterized by being present as particles dispersed in a matrix in a system copolymer (b). Crystalline polyester used in the present invention
(a) has a melting point of 50 to 95°C, but more preferably has a melting point of 60 to 95°C, and the temperature of the melting point is a nonlinear styrene-acrylic copolymer (b)
It is preferable to have a softening point lower than that of . When the crystalline polyester (a) satisfies these conditions, the crystalline polyester (a) will melt at a lower temperature than the nonlinear styrene-acrylic copolymer (b) will soften, As a result, the entire toner can be softened at a low temperature, so the minimum fixing temperature of the toner can be lowered. When the melting point of the crystalline polyester (a) is higher than 95°C, the melting point is not much different from the softening point of the nonlinear styrene-acrylic copolymer (b), or on the contrary, it becomes higher. , the minimum fixing temperature cannot be lowered too low. crystalline polyester
If the melting point of (a) is less than 50°C, the minimum fixing temperature can be lowered, but the blocking resistance will deteriorate. Further, the crystalline polyester (a) is hard and has a penetration degree of 5.0 or less at a temperature of 25°C. When using a soft material with a penetration of more than 5.0,
The obtained toner begins to film on the carrier particles and the surface of the photoreceptor, and its fluidity deteriorates, resulting in a decrease in developability and a failure to obtain a good image. In addition, the crystalline polyester (a) has a weight average molecular weight Mw of 3000 to 20000 and a number average molecular weight Mn measured by gel permeation chromatography.
is between 1000 and 15000. Weight average molecular weight
If Mw is less than 3000 or number average molecular weight
When Mn is less than 1000, the toner has poor blocking resistance. Also weight average molecular weight
When Mw exceeds 20,000 or when the number average molecular weight Mn exceeds 15,000, the viscosity of the toner when melted becomes high, making it impossible to obtain good fixing properties. In addition, weight average molecular weight Mw and number average molecular weight Mn
The value of can be obtained by various methods, but
There may be slight differences due to differences in measurement methods, so
In the present invention, it is determined by the following measurement method. 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/20ml.
Inject 2 mg of tetrahydrofuran sample solution (sample weight) and perform measurement. 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 created 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. The content of such crystalline polyester (a) in the total binder resin is 5 to 40% by weight. If this content exceeds 40% by weight, the offset resistance or fluidity of the toner deteriorates, making it impossible to obtain a good image. Conversely, if the proportion is less than 5% by weight, the minimum fixing temperature will be high. The crystalline polyester (a) is present in the toner particles as particles dispersed in a matrix in the nonlinear styrene-acrylic copolymer (b), and it is necessary to ensure that such a state is achieved. The crystalline polyester (a) and the nonlinear styrene-acrylic copolymer (b) are considered to be incompatible with each other.
If these resins are compatible with each other, the glass transition point of the toner will be lowered, and the blocking resistance of the toner will be lowered. Here, "incompatibility" means that in a temperature range lower than the glass transition point of the nonlinear styrene-acrylic copolymer (b), at least a portion of the crystalline polyester (a) forms crystalline particles. It means that it shows a cloudy state. As described above, as a result of the crystalline polyester (a) being held as dispersed particles by the network structure of the non-linear styrene-acrylic copolymer (b), the crystalline polyester (a) is contained in the toner particles. This prevents the crystalline polymer from being released even when the toner particles come into contact with carrier particles or the surface of the photoreceptor, thus preventing filming and improving the fluidity of the toner. It is thought that this results in a good image quality and that a clear visible image can be formed after all. In the present invention, "crystalline polyester" means a polyester in which at least a portion thereof has a crystal structure, and a homopolymer or copolymer in which at least one component is crystalline, that is, a partially crystalline polyester. including. Such crystalline polyesters exhibit a sharp and distinct melting point, and at temperatures below the melting point, the crystallized portions cause clouding. The crystallinity of a polymer is e.g.
It can be measured by the method of ASTM D-1248-65. The melting point Tm of the crystalline polyester (a) and the glass transition point Tg of the nonlinear styrene-acrylic copolymer (b) were determined as follows. <Melting point Tm> According to differential scanning calorimetry (DSC), the
The melting peak value when 10 mg is heated at a constant temperature increase rate (10°C/min) is the melting point Tm. <Glass transition point Tg> According to differential scanning calorimetry (DSC), the
Heating 10mg at a constant heating rate (10℃/min),
From the intersection of the baseline and the slope of the endothermic peak,
Obtain the glass transition point Tg. Penetration in the present invention is measured according to JIS K2235-1980. Specifically, the value is the penetration depth expressed in units of 0.1 mm when a needle having a conical tip with a diameter of about 1 mm and an apex angle of 9 degrees is penetrated into a sample under a constant load. The test conditions were a sample temperature of 25°C, a load of 100g, and a penetration time of 5 seconds. Specific examples of the crystalline polyester resin (a) in the present invention include polyethylene sebacate, polyethylene adipate, polyethylene suberate, polyethylene succinate, polyethylene-p-
(carbophenoxy) undecaate, polyethylene p-(carbophenoxy) butyrate, polyethylene p-phenylene diacetate, polyhexamethylene carbonate, polyhexamethylene p-(carbophenoxy) undecaate,
Polyhexamethylene oxalate, polyhexamethylene sebacate, polyhexamethylene decanedioate, polyoctamethylene dodecanedioate, polynonamethylene azelate, polynonamethylene terephthalate, polydecamethylene adipate, polydecamethylene azelate, poly Decamethylene oxalate, polydecamethylene sebacate, polydecamethylene succinate, polydecamethylene dodecanedioate, polydecamethylene octatedecanedioate, polytetramethylene sebacate, polytetramethylene-p-phenylene diacetate , polytrimethylene dodecanedioate, polytrimethylene octadecanedioate, polytrimethylene oxalate, poly-p-
Xylene adipate, poly-p-xylene sebacate, poly-4,4'-isopropylidene diphenylene adipate, poly-4,4'-isopropylidene phenylene malonate, polyhexamethylene-
Decamethylene sebacate, polydecamethylene sebacate terephthalate, polydecamethylene sebacate
2-methyl-1,3-propanediol-dodecanedioate and others can be mentioned. The above-mentioned crystalline polyester resin is obtained by a polycondensation reaction of alcohol and a carboxylic acid compound, and examples of the alcohol include ethylene glycol, diethylene glycol, 1,3
Propylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, nonamethylene glycol,
decamethylene glycol, 4,4'-isopropylidene biphenol, p-xylylene glycol,
Neopentyl glycol, cyclohexanedimethanol, polyoxyethylenated bisphenol A, polyoxypropylenated bisphenol A,
Others can be mentioned. In addition, carboxylic acid compounds include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid,
Suberic acid, glutaconic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, fumaric acid, mesaconic acid, citraconic acid,
Mention may be made of itaconic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, anhydrides and lower alkyl esters of these acids, and others. The nonlinear styrene-acrylic copolymer (b) used in the present invention is the above-mentioned crystalline polyester
(A) is strongly retained in the toner particles, and also functions to impart releasability to the fixing roller when melted during fixing. Such a non-linear styrene-acrylic copolymer (b) has a glass transition point Tg of 40 to 80°C, preferably
It is necessary that the toner has a temperature of 50 to 70°C, and if the glass transition point Tg of the nonlinear styrene-acrylic copolymer (b) used is less than 40°C, the toner tends to block and has poor offset resistance. tends to be low. Further, when the glass transition point Tg exceeds 80° C., the minimum fixing temperature of the toner becomes high. The nonlinear styrene-acrylic copolymer (b) has a softening point Tsp of 100 to 150°C, preferably 110 to 140°C. When the softening point is less than 100℃,
Toner tends to block easily and has low offset resistance. When the softening point exceeds 150°C, the minimum fixing temperature of the toner becomes high. In the present invention, the softening point Tsp is measured using a flow tester (manufactured by Shimadzu Corporation) under a load of 20
Kg/cm ² , nozzle diameter 1mm, nozzle length 1mm,
Flow tester plunger drop amount vs. temperature obtained when preheating at 40℃ for 10 minutes at a heating rate of 6℃/min and measuring and recording a sample amount of 1cm ³ (weight expressed as intrinsic specific gravity x 1cm ³ ) When the height of the S-curve in the curve (softening flow curve) is h, the temperature is h/2. Furthermore, the non-linear styrene-acrylic copolymer (b) used is harder than the crystalline polyester (a) and has a penetration rate of 1.0 or less. By using the hard non-linear styrene-acrylic copolymer resin (b), it is possible to obtain the effect that the resulting toner has good fluidity and also has good triboelectric charging properties. Further, the gel content in this nonlinear styrene-acrylic copolymer resin (b) is preferably 50% by weight or less. The nonlinear styrene-acrylic copolymer (b) in the present invention includes (1) a styrene monomer, (2) an acrylic ester and/or a methacrylic ester monomer, and (3) an aromatic vinyl compound, an acrylic It is a copolymer of monomers having two or more vinyl groups selected from acid esters and methacrylic esters. Examples of the styrenic monomer for obtaining such a copolymer include styrene, o-methylstyrene, m-methylstyrene,
p-methylstyrene, α-methylstyrene, p-
Ethylstyrene, 2,4-dimethylstyrene, p
-n-butylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-
Decylstyrene, p-n-dodecylstyrene, p
-methoxystyrene, p-phenylstyrene, p
-Chlorstyrene, 3,4-dichlorostyrene, and the like. Specific examples of acrylic ester or methacrylic ester monomers include methyl acrylate, ethyl acrylate, and n-acrylic acid.
Butyl, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate , methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate,
Examples include n-octyl methacrylate, dodecyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, and diethylaminoethyl methacrylate. Furthermore, monomers having two or more vinyl groups for nonlinearization include, for example, divinylbenzene, divinylnaphthalene, derivatives thereof, other aromatic divinyl compounds; ethylene glycol diacrylate, ethylene glycol dimethacrylate, and divinyl divinyl compounds; Methylolpropane triacrylate, other acrylic esters or methacrylic esters having two or more double bonds,
Others can be mentioned. The amount of the monomer having two or more vinyl groups used is 0.01 to 20% by weight, preferably 0.1 to 10% by weight, and more preferably 0.1 to 5% by weight based on the total monomers. The toner of the present invention contains a polyolefin having a softening point of 110 to 150° C. as determined by the ring and ball method as a fixability improving agent. The toner of the present invention may also contain other resins such as polyester, polyamide, polyurethane, polyurea,
Although resins such as epoxy resins and phenol formalin resins may be contained, the proportion thereof is preferably in the range of 50% by weight or less of the resin. In the present invention, toner components such as a colorant, a charge control agent, magnetic particles, and other property improving agents may be dispersed and contained in the toner particles. Examples of colorants include carbon black,
Nigrosine dye, aniline blue, calco oil blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow,
Methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengal, mixtures thereof, and the like can be used. The amount of this colorant used is
It is preferable to use 1 to 20 parts by weight per 100 parts by weight of the binder resin. If this amount is too small, the coloring density and hiding power may be insufficient, while if it is too large, the tone of the image will become dark and the toner may become electrified. In some cases, unfavorable effects may appear on properties or physical properties during heat fixing. As the magnetic material, known materials can be used, such as metals exhibiting ferromagnetism such as cobalt, iron, and nickel, aluminum, cobalt, steel,
Alloys of metals such as lead, magnesium, nickel, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium, etc., and mixtures thereof, aluminum oxide, iron oxide, copper oxide, nickel oxide , metal compounds containing metal oxides such as zinc oxide, titanium oxide, magnesium oxide, etc. can be used. These magnetic materials have an average particle size of 0.1~
Preferably, it is uniformly dispersed in the binder resin in the form of fine particles of 1 μm. When the finally obtained toner is used as a one-component developer, the content of the magnetic material is preferably 20 to 70 parts by weight, more preferably 40 to 70 parts by weight, per 100 parts by weight of the toner. As the charge control agent, conventionally known ones can be used. To give an example of a preferred method for manufacturing the toner of the present invention, first, a material resin for the binder resin or a toner component such as a colorant is added thereto as necessary is melt-kneaded using, for example, an ecrutruder;
After cooling, it is finely pulverized using a jet mill or the like, and then classified to obtain a toner having a desired particle size. Alternatively, a toner having a desired particle size can be obtained by melting and kneading the toner using an extruder and then spraying it in a molten state using a spray dryer or dispersing it in a liquid. [Effect] As described above, in the electrostatic image developing toner of the present invention, the crystalline polyester (a) with a low melting point is mixed in the nonlinear styrene-acrylic copolymer (b) with an appropriate glass transition point. It will be in a state where it is strongly held,
Therefore, due to the low softening point of the crystalline polyester (a), the minimum fixing temperature of the toner can be lowered, and the non-linear styrene-acrylic copolymer (b) has sufficient mold releasability. As a result, offset phenomena are less likely to occur, and toner blocking and filming are less likely to occur.As a result, good visible images can be formed even during high-speed continuous copying. [Examples] Examples of the present invention will be described below, but the present invention is not limited by these in any way.
Note that the numbers in the examples are parts by weight unless otherwise specified. Production of crystalline polyester [Production of crystalline polyester A] 230.0 g (1.0 mole) of dimethyl sebacate, 147.2 g (1.1 mole) of hexamethylene glycol, 2.0 g of lead monoxide, and 2.0 g of di-tert-butylhydroquinone.
was placed in a four-neck round-bottomed flask with a capacity of 1, equipped with a thermometer, a stirrer, a glass nitrogen inlet tube, and a flow-down condenser.The flask was then placed on an oil bath, and nitrogen gas was introduced through the nitrogen inlet tube. was introduced to maintain an inert atmosphere inside the reaction vessel, the reaction vessel was heated to a temperature of 160°C, and the methanol distilled out was removed. When no more methanol was distilled out, the temperature was raised to 200°C, and the pressure was gradually reduced to 0.05 mmHg. The progress of the reaction was followed by monitoring the melting point of the product, and when the melting point reached 65° C., the reaction was stopped and cooled to room temperature. In the manner described above, a cloudy crystalline polyester was obtained. This is called crystalline polyester A.
This crystalline polyester A had a melting point Tm of 65°C, a penetration rate of 4.0, a weight average molecular weight Mw of 6500, and a number average molecular weight Mn of 3400. [Production of crystalline polyester B] Using 146.0 g (1.0 mole) of dimethyl succinate, 149.0 g (2.4 mole) of ethylene glycol, 3.0 g of calcium acetate dihydrate, and 0.1 g of antimony trioxide, the above-mentioned The reaction was carried out in a manner similar to the method for producing crystalline polymer A. That is, the inside of the reaction vessel is kept in an inert atmosphere and heated to react at a temperature of 160°C, the methanol distilled out is removed, and once no more methanol is distilled out, the temperature is gradually raised to 200°C. , the ethylene glycol distilled out is removed, and when the amount of distilled water becomes small, the pressure is increased.
The reaction was completed by gradually reducing the pressure to 0.05 mmHg, and then cooled to room temperature to obtain a cloudy crystalline polyester. This will be referred to as crystalline polyester B. The melting point Tm of this crystalline polyester B is 95℃,
The penetration was 1.0, the weight average molecular weight Mw was 8000, and the number average molecular weight Mn was 3300. [Production of crystalline polyester C] Using 174.0 g (1.0 mole) of dimethyl adipate, 191.7 g (1.1 mole) of decamethylene glycol, 2.0 g of lead monoxide, and 2.0 g of di-tert-butylhydroquinone, A reaction was carried out in the same manner as in the production of polyester A to obtain a crystalline polyester. This is designated as crystalline polyester C. The melting point Tm of this crystalline polyester C is 78℃,
The penetration was 2.0, the weight average molecular weight Mw was 8300, and the number average molecular weight Mn was 3400. [Manufacture of crystalline polyester D] Using 174.0 g (1.0 mole) of dimethyl adipate, 149.0 g (2.4 mole) of ethylene glycol, 3.0 g of calcium acetate dihydrate, and 0.1 g of antimony trioxide, A reaction was carried out in the same manner as in the production of polyester B to obtain a crystalline polyester. This is designated as crystalline polyester D. The melting point Tm of this crystalline polyester D is 47℃,
The penetration was 6.0, the weight average molecular weight Mw was 4600, and the number average molecular weight Mn was 2100. [Production of crystalline polyester E] 194.0 g (1.0 mole) of dimethyl terephthalate, 114.5 g (1.1 mole) of pentamethyl glycol, 2.0 g of lead monoxide, and 2.0 g of di-tert-butylhydroquinone.
was reacted in the same manner as in the production of crystalline polyester A to obtain a crystalline polyester. This is called crystalline polyester E. The melting point Tm of this crystalline polyester E is 134℃,
The penetration was 1.0, the weight average molecular weight Mw was 6800, and the number average molecular weight Mn was 2700. Production of non-linear styrene-acrylic copolymer [Production of non-linear styrene-acrylic copolymer A] Styrene 83.5 parts n-butyl acrylate 15 parts Divinylbenzene 1.5 parts Benzoyl peroxide 5 parts Stirrer, thermometer and 2% by weight tricalcium phosphate in a four-necked flask equipped with a nitrogen inlet tube.
Add 600 ml of water containing 0.2% by weight of sodium dodecylbenzenesulfonate, create a nitrogen gas atmosphere in the reaction vessel via a nitrogen introduction tube, and add 200 g of the above composition under stirring at room temperature to suspend it. ,
Next, the temperature was raised to 80°C and the reaction was allowed to proceed for about 8 hours. After the reaction, the system is cooled, hydrochloric acid is added, filtration and washing are repeated to remove tricalcium phosphate and sodium dodecylbenzenesulfonate, and then dried to obtain non-linear styrene.
An acrylic copolymer was obtained. This is referred to as nonlinear styrene-acrylic copolymer A. This nonlinear styrene-acrylic copolymer A had a softening point Tsp of 131°C, a glass transition point Tg of 65°C, and a penetration degree of 1.0 or less. [Manufacture of non-linear styrene-acrylic copolymer B] Styrene 73.5 parts n-butyl acrylate 25 parts divinylbenzene 1.5 parts Benzoyl peroxide 5 parts Non-linear styrene-acrylic copolymer except the one using the above composition In the same manner as in combination A, non-linear styrene
An acrylic copolymer was obtained. This is referred to as nonlinear styrene-acrylic copolymer B. This nonlinear styrene-acrylic copolymer B had a softening point Tsp of 97°C and a glass transition point Tg of 39°C. [Manufacture of non-linear styrene-acrylic copolymer C] Styrene 93.5 parts n-butyl acrylate 5 parts divinylbenzene 1.5 parts Benzoyl peroxide 5 parts Non-linear styrene-acrylic copolymer except that using the above composition In the same manner as in combination A, non-linear styrene
An acrylic copolymer was obtained. This is referred to as nonlinear styrene-acrylic copolymer C. This nonlinear styrene-acrylic copolymer C had a softening point Tsp of 153°C and a glass transition point Tg of 81°C. [Production of non-linear styrene-acrylic copolymer D] Styrene 68.0 parts Methyl methacrylate 10 parts n-butyl acrylate 20 parts Divinylbenzene 0.3 parts Non-linear styrene-acrylic copolymers using the above composition Similarly to A, non-linear styrene
An acrylic copolymer was obtained. This is referred to as nonlinear styrene-acrylic copolymer D. This nonlinear styrene-acrylic copolymer D had a softening point Tsp of 123°C and a glass transition point Tg of 57°C. Manufacture of toner The composition shown in Table 1 was heated and kneaded in an extruder, cooled, and then coarsely pulverized, further finely pulverized in a supersonic jet mill, and classified in an air classifier to obtain colored particles. 100 parts by weight of the colored particles and 0.6 parts by weight of silica fine powder "R-972" (manufactured by Nippon Aerosil Co., Ltd.) were mixed in a V-type mixer,
Toners 1 to 4 of the present invention and comparative toners 1 to 4
Comparative toner 7 was obtained. In Table 1, carbon black "Mogull L" (manufactured by Kabot Corporation) was used as the "coloring agent".
In addition, the fixing properties improvers “PP-A” and “PP-
B” is polypropylene “viscol” respectively.
660P” (softening point 135℃, manufactured by Sanyo Kasei Kogyo Co., Ltd.) and polypropylene “Viscol 550P” (softening point
145℃, manufactured by Sanyo Chemical Industries, Ltd.), "PE-A" is polyethylene wax "Mitsui Hiwax 400P"
(Softening point: 132°C, manufactured by Mitsui Petrochemicals). The softening point of the fixability improver is a value measured according to the ring and ball method JIS K2531. The fluidity of each of the toners obtained as described above was visually determined, and the temperature
The sample was left in an environment of 60% relative humidity and 60% Celsius for one day, and the presence or absence of blocking (aggregation) was examined. Furthermore, a developer was prepared by mixing 4 parts of each of the above toners with 96 parts of a spherical iron powder carrier coated with a styrene-methyl methacrylate copolymer (composition ratio 3:7), and using this developer, An image formation test was conducted in which copied images were continuously formed 30,000 times using an electrophotographic copying machine "U-Bix1600" (manufactured by Konishiroku Photo Industry Co., Ltd.) with the line speed of the fuser set at 70 mm/sec. The resulting copied images were evaluated for the presence or absence of fog and the image quality at the initial and final stages of the test, and the presence or absence of filming on the photoreceptor of the electrophotographic copying machine was also examined. In addition, by forming an unfixed image using the above electrophotographic copying machine and fixing it by changing the fixing temperature using a separately prepared fixing tester, we determined the lowest fixing temperature and the lowest temperature at which an offset phenomenon occurs for each toner (offset occurrence temperature). ) was sought. Specifically, the minimum fixing temperature is the minimum temperature at which no stains occur when the copied image is rubbed with a JK wiper, and the offset generation temperature is the minimum temperature at which stains do not appear on subsequent sheets of paper fed to the fuser. The lowest temperature at which this occurs was determined. The above results are shown in Table 2. As is clear from the results in this table, the toner of the present invention has a low minimum fixing temperature, good offset resistance, good blocking resistance, and excellent fluidity, filming resistance, and durability. It is possible to form clear visible images with high image density and little fog.

【table】

【table】

Claims (1)

[Claims] 1 (a) A melting point of 50 to 95°C, a penetration of 5.0 or less, a weight average molecular weight of 3,000 to 20,000, and a number average molecular weight of
1000-15000, 5 for the entire binder resin
~40% by weight of crystalline polyester, and (b) (1) styrenic monomer, (2) acrylic ester and/or methacrylic ester, and (3) aromatic vinyl compounds, acrylic ester and methacrylic ester Non-linear styrene having a softening point of 100 to 150°C, a glass transition point of 40 to 80°C, and a penetration of 1.0 or less, obtained by polymerizing a monomer having two or more vinyl groups selected from the following. It contains a binder resin made of an acrylic copolymer and a polyolefin having a softening point of 110 to 150°C, and the melting point of the crystalline polyester (a) is lower than that of the nonlinear styrene-acrylic copolymer (b). The crystalline polyester (a) and the non-linear styrene-acrylic copolymer (b) are incompatible with each other, and the crystalline polyester (a) is lower than the softening point of the non-linear styrene-acrylic copolymer (b). - A toner for electrostatic image development for heat roller fixation, characterized in that particles are dispersed in a matrix in an acrylic copolymer (b).