JPS6349221B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new toner for developing electrostatic images in electrophotography, electrostatic printing, electrostatic recording, and the like.

The novel toner for developing electrostatic images of the present invention is a fine powder developer used in the so-called dry developing method, and is suitable for dry developing methods such as the cascade method, bristle brush method, magnetic brush method, impression method, powder kraut method, etc. It can be used in a developing system and is characterized by containing a low molecular weight polymer and an insoluble and infusible high molecular weight polymer as the main resin components.

As is well known, toners for developing electrostatic images are generally composed of a resin component, a colorant component such as a pigment or dye, and additive components such as a plasticizer and a charge control agent.The resin component may be natural or synthetic. Resins are used alone or in appropriate combinations. Many improvements have been proposed regarding the resin components of toners suitable for dry development methods, which have undergone rapid technological development in recent years. In particular, electrophotographic copying machines aimed at high-speed copying use a heated roller fixing method, in which a toner image obtained by development on an electrostatic recording medium (photosensitive drum) is first transferred to a transfer sheet such as paper. After the transfer, the transfer sheet is passed through a fixing roller that performs heat and pressure bonding to fuse the toner image to the sheet, thereby performing fixation. However, since the surface of the fixing roll and the toner image come into pressure contact in a heated and molten state, a part of the toner forming the image adheres to and is transferred to the fixing roll, and this is transferred again onto the next sheet to be fixed, resulting in so-called "offset development". ” and causes stains on the fixing sheet. Therefore, there has been a long-awaited demand for a resin component that prevents the toner from adhering to the surface of the fixing roller even in high-speed copying, and that allows for sufficient fixing.

Japanese Patent Publication No. 51-23354 discloses a resin component for a toner with excellent so-called "offset resistance" that does not cause such an offset phenomenon, with a ratio of 0.005 to the monomer.
The use of resin components containing ~20% by weight crosslinking agent has been proposed. In addition, Japanese Patent Publication No. 55-6895 uses a polystyrene resin with a weight average molecular weight/number average molecular weight of 3.5 to 4.0 as the main resin component to obtain a toner for developing electrostatic images with excellent fixing properties and offset resistance. This is disclosed.

However, in recent years, copying speeds have become faster and faster.
Moreover, as the tendency to desire clear and stable copying has become more pronounced, there has been a strong demand for toners that have even better fixing properties and offset resistance than those of the prior art described above. As a result of extensive research into resin components for toners that can meet these demands, the present inventor has finally invented a toner with better fixing properties and offset resistance than those of the prior art. I was able to complete it.

The electrostatic image developing toner of the present invention contains a low molecular weight polymer and an insoluble and infusible high molecular weight polymer as main resin components. In the present invention, the low molecular weight polymer has a number average molecular weight (hereinafter referred to as _N ) of 3000 to
50000 and weight average molecular weight (hereinafter referred to as _W )
and _N , that is, _W / _N , is less than 3.5, particularly preferably a polymer having _{an N} of 5,000 to 30,000 and _{a W} / _N of less than 3.5. If _N is too low (less than 3000), toner blocking (toner coagulation in the developing device) tends to occur, which is undesirable.
If it is too high, exceeding 50,000, fixing performance will deteriorate, which is not preferable. Further, if _W / _N is 3.5 or more, fixing performance deteriorates, which is not preferable. The "insoluble" of the insoluble and infusible high molecular weight polymer as used herein refers to both "insoluble" and "infusible", and in this case, "insoluble" means AFTM- 407-02
(United States of America, Automotive Paint Testing Methods)
When a press-molded test piece of resin is wrapped in a 300-mesh wire mesh and heated under reflux in acetone for 7 hours, the undissolved resin content is 90% or more, preferably 95% based on the initial weight.
On the other hand, "infusible" means that the acetone-insoluble resin component has a diameter of 0.5 x 1 m / The amount of melting from the nozzle m in the first minute is less than 1 mm.

The toner for developing electrostatic images of the present invention preferably contains 10 to 60% by weight of the low molecular weight polymer and 90 to 40% by weight of the insoluble high molecular weight polymer, particularly based on the total of the low molecular weight polymer and the insoluble and infusible high molecular weight polymer. Preferably 15-50% by weight of low molecular weight polymer and 85-50% by weight of insoluble high molecular weight polymer
50% by weight, most preferably low molecular weight polymers 23-45
The main resin component is 77-55% by weight of an insoluble high molecular weight polymer. Low molecular weight polymer
If the weight of the insoluble polymer is less than 10% by weight and the weight of the insoluble polymer is more than 90% by weight, the fixing properties will deteriorate, which is undesirable. If it is less than 40% by weight, the offset resistance will deteriorate, which is not preferable.

As used herein, the term "main resin component" refers to a resin component that accounts for at least 70% by weight of the resin components contained in the toner for developing electrostatic images.

The (meth)acrylic acid alkyl ester monomers used in the low molecular weight polymer and the insoluble and infusible high molecular weight polymer that constitute the main resin components of the electrostatic image developing toner of the present invention include methyl acrylate and ethyl acrylate. , n-butyl acrylate, isobutyl acrylate, n-octyl acrylate, ethylhexyl acrylate, chloroethyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-methacrylate
- Octyl, dodecyl methacrylate, stearyl methacrylate, etc.

The insoluble and infusible high molecular weight polymer constituting the main resin component of the electrostatic image developing toner of the present invention is
It contains a crosslinking agent as a component, and such crosslinking agents are mainly compounds having two or more polymerizable double bonds, such as aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene, ethylene glycol, and dimethacrylate. , diethylene carboxylic acid esters such as tetraethylene glycol, dimethacrylate, 1,3 butanediol, dimethacrylate, aryl, methacrylate, N,
Examples include N-divinylaniline, divinyl ether, and divinyl sulfide. Divinylbenzene and ethylene glycol dimethacrylate are preferably used.

The low molecular weight polymer used in the present invention is a styrene-(meth)acrylic acid alkyl ester polymer containing 50-100% by weight of styrene and 50-0% by weight of an alkyl (meth)acrylate as monomer units. A particularly preferred example is
70-90% by weight of styrene and 30% n-butyl acrylate
~10% by weight. In addition, the insoluble and infusible high molecular weight polymer is 50 to 100% by weight of styrene, 0 to 50% by weight of alkyl (meth)acrylate, and 0.01 to 2% by weight of crosslinking agent (the total of the three is 100% by weight). A particularly preferred example is a crosslinked styrene-(meth)acrylic acid alkyl ester copolymer containing styrene 70 as a monomer unit.
-90% by weight, 30-10% by weight of n-butyl acrylate and 0.01-2% by weight of crosslinker (the sum of the three being 100% by weight).

The method for producing the main resin component for the toner of the present invention includes low molecular weight polymers such as ionic polymers and radical polymers produced by bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc. A method in which insoluble and infusible high molecular weight polymers produced by bulk polymerization, suspension polymerization, emulsion polymerization, etc. are mixed in the form of a dispersion or solution and then dried, and a method in which the polymers are dried separately and then dried during toner production. A method of dry blending or a method of mixing using an extruder or the like is adopted. Preferably, the method of the present invention is carried out by dissolving a prepolymerized low molecular weight polymer in a monomer for an insoluble and infusible high molecular weight polymer, and then carrying out the polymerization to obtain an insoluble and infusible high molecular weight polymer. A main resin component is obtained, and in this main resin component, a low molecular weight polymer and an insoluble and infusible high molecular weight polymer are mutually dispersed extremely uniformly, so that it is possible to disperse additives such as carbon black during toner production. This process is extremely efficient, resulting in excellent toner productivity, charging characteristics, and storage stability.

The toner for developing an electrostatic image according to the present invention has the above-mentioned resin as the main resin component, but other polymers may be mixed as necessary in addition to the main resin component. I can do it. Other polymers that may be mixed and used in this manner include phenol formaldehyde resins, epoxy resins, polyurethane resins, cellulose resins, polyether resins, xylene resins, and the like.

Further, an appropriate pigment or dye is blended as a coloring agent in the toner for developing an electrostatic image according to the present invention. Examples of such pigments or dyes include carbon black, serco oil blue, Dupont oil red, phthalocyanine blue, aniline blue, nigrosine dye, ultramarine blue, quinoline yellow, malachite green oxalate, mixtures of rose bengal and the like. is added in the amount necessary for coloring the toner.

Furthermore, the toner for developing electrostatic images according to the present invention may further contain a release agent, if necessary. Such compounds include, for example, Cd of stearic acid,
Ba, Ni, Co, St, Cu, Mg, Ca salt, Zn, Mn, Fe, Co, Cu, Pb, Mg salt of oleic acid, Zn, Co, Cu, Mg, Sl, Ca salt of palmitic acid, linoleic acid Zn, Co, Ca salts of acids, Zn of ricinoleic acid, or
Metal salts of higher fatty acids such as Cd salts, Pb salts of caprylic acid, Pb salts of caproic acid, natural and synthetic paraffins and fatty acid esters, or partially saponified products thereof;
There are alkylene bis fatty acid amides and the like, and one or more of these compounds may be mixed as appropriate in the toner of the present invention.

Further, the toner for developing an electrostatic image according to the present invention may further contain other types of toner additives such as a charge control agent and a plasticizer, if necessary.

Therefore, the toner for developing electrostatic images according to the present invention has excellent fixing properties and excellent properties in high-speed electrophotographic copying by containing a low molecular weight polymer and an insoluble and infusible high molecular weight polymer as main resin components. Although it has both offset resistance and excellent blocking resistance, it has been surprisingly found that the present invention also has the completely unexpected effect of having excellent pulverizability during toner production. Ivy. Toner is made into a final product by cooling a molten mixture and then finely pulverizing it with a jet mill, etc. Conventionally, the yield of a product with the desired particle size distribution was about 50% per pass. However, in the present invention,
Final products with a particle size distribution of 10-15μ can be obtained with yields as high as about 70%.

The present invention will be explained in detail below using examples.

Example 1 6.4 kg of styrene, 1.6 kg of butyl acrylate, and 130 g of 2-mercaptoethanol were charged into a polymerization machine of 50 mm, and the inside of the polymerization machine was heated while blowing air at 2/min from a blowing pipe with an inner diameter of 2 m/m. 90℃
The polymerization reaction was carried out for 10 hours.

Next, 1.6 kg of styrene and 400 kg of butyl acrylate.
g, divinylbenzene 16 g, benzene peroxide 16
After adding a mixed solution of 60g of benzoyl peroxide to the above reaction product, 20kg of an aqueous solution of deionized water in which 10g of polyvinyl alcohol (Gohsenol KM-17) was dissolved was added, and the inside of the polymerization machine was heated to 80℃ with stirring for 12 hours.
The polymerization reaction was completed after a period of time. The obtained polymer slurry was subjected to usual post-treatments such as dehydration, washing and drying to obtain 9.9 kg of bead-shaped resin.

When the obtained resin was extracted with THF using a Soxhlet extractor, the extraction reached a constant weight in 40 hours, and the insoluble components (insoluble and infusible high molecular weight polymer) were 55% by weight.
The soluble component (low molecular weight polymer) was divided into 45% by weight. _N of low molecular weight polymer is 8000, _W / _N is 2.1
and the insoluble and infusible high molecular weight polymer is AFTM
In the test of -407-02, the insoluble content was 98%, and the amount of melting was 0.5 mm in the Koka type flow tester test.

After mixing 100 parts of the above resin and 10 parts of carbon black (Diamond Black SH), heat roll at 140℃
Mix well for 20 minutes. After cooling, it is coarsely crushed to a powder of approximately 300μ, and then finely pulverized with a jet mill (IDS-2 type) at an air pressure of 5Kg/cm ² and a feed rate of 4Kg/Hr to obtain an average particle size.
A fine powder of 15μ was obtained and used as a toner.

When we conducted a copying test using the above toner on a commercially available copying machine (Fuji Xerox Model 3500 copying machine), images could be fixed from 125°C, and even at 250°C there was no staining due to toner offset to the heat roll. Even after copying multiple sheets, clear images were obtained that did not smudge.

Example 2 4.0 kg of styrene, 1.0 kg of butyl acrylate, and 80 g of 2-mercaptoethanol were charged into a polymerization machine of 50 mm, and the inside of the polymerization machine was heated to 90°C while blowing air at 2/min from a blowing pipe with an inner diameter of 2 m/m. The polymerization reaction was carried out for 10 hours. Next, 4.0 kg of styrene, 1.0 kg of butyl acrylate, 20 g of divinylbenzene,
After adding a mixed solution of 70 g of benzoyl peroxide to the above reaction product, 20 kg of an aqueous solution of deionized water in which 10 g of Gohsenol KM-7 was dissolved was added and heated to 80°C with stirring.
The polymerization reaction was completed by holding for 12 hours. The rest of the procedure was the same as in Example 1, and the resulting resin contained 76% by weight of the insoluble component (insoluble and infusible high molecular weight polymer), 24% by weight of the soluble component (low molecular weight polymer), and 24% by weight of the low molecular weight polymer. _N was 8500 _W / _N was 2.5, and the AFTM test value of the insoluble and infusible high molecular weight polymer was 97% insoluble content, and the high pressure flow tester test value was 0.4 mm.

When this product was made into toner using the same method as in Example 1, the processing capacity of the jet mill was 2.5Kg/Hr.
(average 13μ), and the fixation in the copying test was 130
The offset phenomenon did not occur even at 250°C, and clear, clean images were obtained even after 20,000 copies were made.

Example 3 5.6 kg of styrene, 1.4 kg of butyl acrylate, and 110 g of 2-mercaptoethanol were charged into a polymerization machine of 50 mm, and the inside of the polymerization machine was heated to 90°C while blowing air at 2/min from a blowing tube with an inner diameter of 2 m/m. The polymerization reaction was carried out for 10 hours.

Next, 2.4 kg of styrene and 600 kg of butyl acrylate.
g, divinylbenzene 17 g, benzoyl peroxide 65
g of the mixed solution was added to the above reaction product, 20 kg of an aqueous solution of deionized water in which 10 g of Gohsenol KH-17 was dissolved was added, and the inside of the polymerization machine was heated to 80°C with stirring for 12 hours.
The polymerization reaction was completed after a period of time.

The rest of the procedure was the same as in Example 1, and the resulting resin contained 62% by weight of the insoluble component (insoluble and infusible high molecular weight polymer), 38% by weight of the soluble component (low molecular weight polymer), and 38% by weight of the low molecular weight polymer. _N is 8200 _W / _N is 2.3, and the AFTM test value of the insoluble and infusible high molecular weight polymer is 97% insoluble content, and the Koka flow tester test value is 0.6
It was warm in mm.

When this material was made into a toner using the same method as in Example 1, the throughput of the jet mill was 3Kg/Hr (average 15μ), and the fixing rate in the copying test was 125°C.
The offset phenomenon did not occur even at 250°C, and clear, clean images were obtained even after 20,000 copies were made.

Example 4 5.6 kg of styrene, 2.4 kg of butyl acrylate, and 260 g of 2-mercaptoethanol were charged into a polymerization machine of 50 mm, and the inside of the polymerization machine was heated while blowing air at 2/min from a blowing pipe with an inner diameter of 2 m/m. 90℃
The polymerization reaction was carried out for 10 hours. Next, 1.4Kg of styrene,
Butyl acrylate 600g, divinylbenzene 32g,
After adding a mixed solution of 60 g of benzoyl peroxide to the above reaction product, 10 g of Gohsenol KH-17 was dissolved and 20 kg of an aqueous solution of deionized water was added, and the mixture was stirred for 80 minutes.
The polymerization reaction was completed by keeping at ℃ for 12 hours. The rest of the procedure was the same as in Example 1, and the resulting resin contained 55% by weight of the insoluble component (insoluble and infusible high molecular weight polymer), 45% by weight of the soluble component (low molecular weight polymer), and 45% by weight of the soluble component (low molecular weight polymer). _N is 5000 _W / _N is 2.8, and the AFTM test value of insoluble and infusible high molecular weight polymer is
At 96%, the Koka type flow tester test value was 0.9 mm.

When this material was made into toner in the same manner as in Example 1, the processing capacity of the jet mill was 4 kg/Hr (average
12μ), and fixing in the copying test was possible from 120°C, and no offset phenomenon occurred even at 250°C, and clear images with little staining were obtained even after 20,000 copies were made.

Example 5 7.0 kg of styrene, 3.0 kg of butyl acrylate, and 300 g of benzoyl peroxide were charged into a polymerization machine of 50 mm, mixed and dissolved, and then 20 kg of an aqueous solution of deionized water in which 10 g of Gohsenol KH-17 was dissolved was added and polymerized with stirring. The inside of the machine was heated to 80°C and a polymerization reaction was carried out for 12 hours to obtain a soluble resin with M _N of 20,000 and _W / _N of 2.3.

After dissolving 4 kg of the above resin in a mixed solution of 4.8 kg of styrene, 1.2 kg of butyl acrylate, 120 g of ethylene glycol dimethacrylate, and 60 g of benzoyl peroxide, 20 kg of an aqueous solution of deionized water in which 10 g of Gohsenol KH-17 was dissolved was added. The polymerization machine was heated to 80°C while stirring.
The polymerization reaction was carried out for 12 hours. The obtained resin had an insoluble component (insoluble and infusible high molecular weight polymer) of 57% by weight, a soluble component (low molecular weight polymer) of 43% by weight, and _{the N} of the low molecular weight polymer was 21000 _W / _N was 2.5. In addition, the AFTM test value of insoluble and infusible high molecular weight polymers is
The Koka type flow tester value was 0.3 mm at 98%.

When this material was made into a toner using the same method as in Example 1, the throughput of the jet mill was 2.5Kg/Hr (average 14μ), and the fixing rate in the copying test was 130°C.
The offset phenomenon did not occur even at 250°C, and clear, clean images were obtained even after 20,000 copies were made.

Example 6 After 8.0 kg of styrene, 2.0 kg of butyl acrylate, and 800 g of benzoyl peroxide were mixed and dissolved in a polymerization machine of 50, 20 kg of an aqueous solution of deionized water in which 10 g of Gohsenol KH-17 had been dissolved was added and polymerized with stirring. The inside of the machine was heated to 85°C and a polymerization reaction was carried out for 12 hours to obtain a soluble resin (A) (low molecular weight polymer) with _N of 8000 _W / _N of 2.3.

Separately, 8.0 kg of styrene, 2.0 kg of butyl acrylate, 50 g of divinylbenzene, and 100 g of benzoyl peroxide were mixed and dissolved in a polymerization machine of 50. After that, 20 kg of an aqueous solution of deionized water in which 10 g of Gohsenol KH-17 was dissolved was added and stirred. The interior of the polymerization machine was heated to 80℃ and the polymerization reaction was carried out for 12 hours, and the insoluble content was 98% according to the AFTM test value and the Koka flow tester test value.
0.5m/m insoluble and infusible high molecular weight polymer resin (B)
I got it.

After mixing 40 parts of the above resin (A) and 60 parts of resin (B) (10 parts of carbon black (diamond black SH)), coarsely pulverizing the mixture using a Nara-type pulverizer, and then thoroughly kneading the mixture using heated rolls at 140°C for 100 minutes. When the same pulverization operation as in Example 1 was performed, the processing capacity of the jet mill was 2 kg/
Hr (average 13μ), and the fixation in the copying test is
This was possible from 125°C, and even at 250°C, no offset phenomenon occurred and clear images with little dirt were obtained even after 20,000 copies were made.

Comparative Example 1 After mixing and dissolving 6.4 kg of styrene, 1.6 kg of butyl acrylate, 130 g of 2-mercaptoethanol, and 9 g of azobisisovaleronitrile into a polymerization machine of 150, the interior of the polymerization machine was heated to 90°C and heated for 10 hours. A polymerization reaction was carried out. Next, a mixed solution of 1.6 kg of styrene, 400 g of butyl acrylate, 16 g of divinylbenzene, and 60 g of benzoyl peroxide was added to the above reaction product, and then 20 kg of an aqueous solution of deionized water in which 10 g of Gohsenol KH-17 was dissolved was added for polymerization. The inside of the machine was kept at 80°C for 12 hours with stirring to complete the polymerization reaction.

The rest of the procedure was the same as in Example 1, and the resulting resin contained 25% by weight of the insoluble component (low molecular weight polymer), 75% by weight of the soluble component (insoluble and infusible high molecular weight polymer), and 75% by weight of the soluble component (insoluble and infusible high molecular weight polymer). _N is 9000 _W / _N is 3.0,
The AFTM test value of the insoluble and infusible high molecular weight polymer was 98%, and the Koka type flow tester test value was 0.4 mm.

When this material was made into a toner using the same method as in Example 1, the crushing capacity of the jet mill was 4 kg/hr, and in the copying test, fixing was possible from 120°C, and no offset phenomenon was observed even at 200°C, making it possible to print approximately 10,000 copies. Even when copying, clear images with little staining were obtained.

Comparative Example 2 500 g of butyl acrylate and 40 g of thioglycolic acid were placed in the flask of 1, and the inside of the flask was heated to 90°C while blowing air at 200 c.c./min from a blowing pipe with an inner diameter of 0.5 m/m. The polymerization reaction was carried out for 10 hours.

Separately, 50 polymerization machines had 6 kg of styrene, 2 kg of n-butyl methacrylate, and 2 kg of lauryl methacrylate.
Kg, divinylbenzene 20g, benzoyl peroxide
After mixing and dissolving 400 g of the above reaction product and 500 g of the above reaction product, 20 kg of an aqueous solution of deionized water in which 10 g of Gohsenol KH-17 was dissolved was added, and the inside of the polymerization machine was heated to 80°C with stirring and kept for 12 hours to complete the polymerization reaction. I let it happen.

The rest of the procedure was the same as in Example 1, and the resulting resin had 95% by weight of the insoluble component (insoluble and infusible high molecular weight polymer) separated, 5% by weight of the soluble component (low molecular weight polymer), and 5% by weight of the soluble component (low molecular weight polymer). Combined _N is 800, _W / _N is
1.7, and that of insoluble and infusible high molecular weight polymers.
The AFTM test value was 93%, and the Koka type flow tester test value was 0.1 mm.

When this material was made into toner using the same method as in Example 1, the crushing capacity of the jet mill was 1.5Kg/Hr.
(average 18μ), and the fixation in the copying test was 145
℃, and no offset phenomenon appeared even at 250℃. In addition, clear images with few stains were obtained even after making approximately 20,000 copies.

Comparative Example 3 6.4 kg of styrene, 1.6 kg of butyl acrylate, and 520 g of 2-mercaptoethanol were charged into a polymerization machine of 3.50 mm, and the inside of the polymerization machine was heated while blowing air at 2/min from a blowing pipe with an inner diameter of 2 m/m. 90℃
The polymerization reaction was carried out for 10 hours. Next, 1.6Kg of styrene,
Butyl acrylate 400g, divinylbenzene 16g,
After adding 60 g of a mixed solution of benzoyl peroxide to the above reaction product, 20 kg of an aqueous solution of deionized water in which 10 g of Gohsenol KH-17 was dissolved was added, and the interior of the polymerization machine was kept at 80°C for 12 hours with stirring to complete the polymerization. The reaction was completed. The rest of the procedure was the same as in Example 1, and the insoluble component (insoluble and infusible high molecular weight polymer) of the obtained resin was 52%, the soluble component (low molecular weight polymer) was 48% by weight, and the low molecular weight Polymer _N is 2500 _W /
M _N was 3.2. The AFTM test value of the insoluble and infusible high molecular weight polymer was 93%, and the Koka type flow tester test value was 0.8 mm.

When this material was made into a toner using the same method as in Example 1, the crushing capacity of the jet mill was 6 kg/Hr (average 14μ), and fixing in the copying test was possible from 120°C, and no offset phenomenon was found up to 200°C. Ta. In addition, even after copying about 10,000 sheets, clear images with few stains were obtained.

Comparative Example 4 7 kg of styrene, 2 kg of butyl acrylate, 1 kg of stearyl methacrylate, and 100 g of benzoyl peroxide were charged into a polymerization machine of 4. When the inside of the polymerization machine was heated to 80℃ with stirring and the polymerization reaction was carried out for 12 hours, _N was
70000, a soluble resin with _W / _N of 2.3 was obtained.

After dissolving 4 kg of the above resin in a mixed solution of 4.8 kg of styrene, 1.2 kg of butyl acrylate, and 120 g of ethylene glycol dimethacrylate,
Aqueous solution of deionized water containing 10g of KH-17
20 kg was added and the inside of the polymerization machine was heated to 80°C while stirring to complete the polymerization reaction. After that, the same post-treatment operation as in Example 1 was performed, and the insoluble component (insoluble and infusible high molecular weight polymer) of the obtained resin was 56% by weight, the soluble component (low molecular weight polymer) was 44% by weight, _{The N} of the low molecular weight polymer was 73,000 _W / _N was 2.4. In addition, the AFTM test value of insoluble and infusible high molecular weight polymers is 95%.
The test value of Koka type flow tester was 0.6mm.

When this product was made into a toner in the same manner as in Example 1, the crushing capacity of the jet mill was 4 kg/hr, and in a copying test, fixing was possible from 140°C, and no offset development was found up to 200°C. Furthermore, even after copying about 10,000 sheets, clear images with few stains were obtained.

Comparative Example 5 5 kg of toluene, 5 kg of n-butyl acetate, and 10 g of hydroquinone were charged into a 50-sized polymerization machine, and the inside of the polymerization machine was heated to 90°C. This stuff contains 8 kg of styrene.
Butyl acrylate 2kg, benzoyl peroxide 150g
A mixed solution of
The polymerization reaction was continued for hours. The obtained polymer solution
Gohsenol KH-17 was reprecipitated in 100 g of methanol and separated as a flaky resin, and 4 kg of it was dissolved in a mixed solution of 4.8 kg of styrene, 1.2 kg of butyl acrylate, 16 g of divinylbenzene, and 60 g of benzoyl peroxide. 20 kg of an aqueous solution of deionized water in which 10 g of the deionized water had been dissolved was added and charged into a 50 polymerization machine, and the interior of the polymerization machine was heated to 80°C with stirring to carry out a polymerization reaction for 12 hours. The resulting resin contained 57% by weight of insoluble components (insoluble and infusible high molecular weight polymer), 43% by weight of soluble components (low molecular weight polymer), and _N of the low molecular weight polymer.
35000 _W / _N was 4.8. The AFTM test value of the insoluble and infusible high molecular weight polymer was 95%, and the Koka flow tester test value was 0.6 mm.

When this material was made into toner using the same method as in Example 1, the crushing capacity of the jet mill was 1.5 Kg/Hr, and fixing in the copying test was possible from 140°C.
No offset development was found even at 200°C. Also, even after making approximately 10,000 copies, clear images with little dirt were obtained.

Comparative Example 6 5.6 kg of styrene, 1.4 kg of butyl acrylate, and 110 g of 2-mercaptoethanol were charged into a polymerization machine of 6.50, and the inside of the polymerization machine was heated to 90°C while blowing air at 2/min from a blowing pipe with an inner diameter of 2 m/m. The polymerization reaction was carried out for 10 hours.

Next, 2.4 kg of styrene and 600 kg of butyl acrylate.
g, 650 g of ethylene glycol dimethacrylate,
After adding a mixed solution of 200 g of carbon tetrachloride and 65 g of benzoyl peroxide to the above reaction product,
Aqueous solution of deionized water containing 10g of KH-17
20 kg was added and the inside of the polymerization machine was maintained at 80°C for 12 hours with stirring to complete the polymerization reaction.

The rest of the procedure was the same as in Example 1, and the resulting resin contained 61% of the insoluble component (insoluble and infusible high molecular weight polymer).
Weight%, soluble components (low molecular weight polymer) 39% by weight,
_{The N} of the low molecular weight polymer was 8300 and _{the W} / _N was 2.5, but the AFTM test value of the insoluble and infusible high molecular weight polymer was 85% insoluble content, and the Koka type flow tester test value was 5 mm. This was outside the definition of infusible according to the present invention.

When this material was made into a toner using the same method as in Example 1, the throughput of the jet mill was 1.5Kg/Hr (average 10μ), and the fixing rate in the copying test was 145°C.
It was discovered that images became smeared due to the offset phenomenon at 180°C, and that the smearing became noticeable after about 5,000 copies were made.

Comparative Example 7 8.0 kg of styrene, 2.0 kg of butyl acrylate, and 800 g of benzoyl peroxide were charged into a polymerization machine of 7 50, mixed and dissolved, and then 20 kg of an aqueous solution of deionized water in which 10 g of Gohsenol KH-17 was dissolved was added and polymerized with stirring. The inside of the machine was heated to 85°C and a polymerization reaction was carried out for 12 hours to obtain a soluble resin (A) (low molecular weight polymer) with _N of 8000 _W / _N of 2.3.

Separately, 50 polymerization machines contain 8.0 kg of styrene, 2.0 kg of butyl acrylate, 50 g of divinylbenzene, 50 g of n-lauryl mercaptan, and 100 kg of benzoyl peroxide.
After mixing and dissolving g, add Gohsenol KH.
-20Kg of deionized water solution containing 10g of 17
was added, the inside of the polymerization machine was heated to 80℃ with stirring, and the polymerization reaction was carried out for 12 hours, and the insoluble content was 70% according to the AFTM test value.
Resin (B) (insoluble and infusible high molecular weight polymer) having a test value of 6 mm using a Koka type flow tester was obtained.

After mixing 25 parts of the above resin (A), 75 parts of resin (B), and 10 parts of carbon black (Diamond Black SH), the mixture was coarsely crushed and finely crushed in the same manner as in Example 1 to form a toner. Grinding capacity is 1.5
Kg/Hr (average 15μ), fixation in copying tests was possible from 145°C, and image staining due to offset phenomenon was observed at 190°C, and it was discovered that the image became significantly stained after about 5000 copies were made.

Comparative Example 8 (Additional test of Example 1 of Japanese Patent Publication No. 51-23354) 7 kg of styrene and n of methacrylic acid were added to a polymerization machine of 50.
- After mixing and dissolving 3 kg of butyl, 98 g of ethylene glycol dimethacrylate, 91 g of n-lauryl mercaptan, and 200 g of azobisisobutyronitrile, add 20 kg of an aqueous solution of deionized water in which 10 g of Gohsenol KH-17 was dissolved and add to the polymerization machine. The interior was kept at 80°C for 12 hours with stirring to carry out the polymerization reaction. After that, the same post-treatment operation as in Example 1 was carried out, and the obtained resin was subjected to Soxhlet extraction with THF.
A constant extraction weight was reached within hours, and 63% by weight of insoluble components were separated. The AFTM test value of the insoluble component was 50%, the Koka flow tester test value was 8 mm, and the soluble component _N was 25000 and _W / _N was 2.3.

When this material was made into toner using the same method as in Example 1, the crushing capacity of the jet mill was 1.2Kg/Hr.
(average 17μ), and the fixation in the copying test was 160℃.
Although the offset phenomenon was not detected up to 220°C, conspicuous staining of the images appeared after about 10,000 copies were made.

Comparative Example 9 (Additional test of Example 8 of Japanese Patent Publication No. 55-6895) 20 kg of toluene was charged into a polymerization machine of 50, and the temperature was heated to 110°C.
400g of t-butyl pivalate peroxide,
10.8 kg of a styrene solution in which 400 g of benzoyl peroxide was mixed and dissolved was added into the polymerization machine over 4 hours. The polymerization reaction was further continued at the same temperature for 2 hours, and then cooled to 50°C. The resulting polymer solution was reprecipitated in 100 ml of methanol to separate the flaky soluble resin (A). _N of this thing is 8500, _W / _N is 4.5
It was hot.

Separately, use styrene instead of the styrene solution above.
8.2Kg, n-butyl methacrylate 1.8Kg, t-butyl pivalate peroxide 400g, benzoyl peroxide 400g
The same polymerization and post-treatment operations were performed except that 10.8 kg of the mixed solution was used, and _N was 8200 _W /
A soluble resin (B) with _N of 4.3 was obtained.

A mixture of 50 parts of the above resin (A) and 50 parts of resin (B)
When Soxhlet extraction was performed using THF, insoluble components were not separated, and the mixture itself was
When subjected to the AFTM test, it was 2%, and when subjected to the Koka type flow tester test, it was 15 mm.

When this material was made into a toner using the same method as in Example 1, the crushing capacity of the jet mill was 2 kg/hr, and in the copying test fixing was possible from 145°C, but offset development was observed at 170°C, and 5000 copies were made. The image was noticeably smudged.

Claims (1)

[Scope of Claims] 1. A toner for developing electrostatic images containing a low molecular weight polymer and an insoluble and infusible high molecular weight polymer as main resin components, wherein the low molecular weight polymer has a number average molecular weight of 3000 to 50000. and is a styrene-(meth)acrylic acid alkyl ester copolymer having a weight average molecular weight/number average molecular weight of less than 3.5, and is crosslinked with the insoluble and infusible high molecular weight polymer.
It is an acrylic acid alkyl ester copolymer,
A toner for developing an electrostatic image, wherein the low molecular weight polymer is 23 to 45% by weight and the insoluble high molecular weight polymer is 77 to 55% by weight based on the total of the low molecular weight polymer and the insoluble high molecular weight polymer. . 2 Styrene (meth) which is the low molecular weight polymer
In the acrylic acid alkyl ester copolymer,
The toner according to claim 1, wherein the styrene content is 50 to 100% by weight, and the (meth)acrylic acid alkyl ester is 0 to 50% by weight. 3. In the crosslinked styrene-(meth)acrylic acid alkyl ester copolymer which is the insoluble and infusible high molecular weight polymer, styrene is 50 to 100% by weight,
3. The toner according to claim 1, wherein the (meth)acrylic acid alkyl ester is 0 to 50% by weight and the crosslinking agent is 0.01 to 2% by weight. 4. The toner according to any one of claims 1 to 3, wherein the crosslinking agent is divinylbenzene. 5 The (meth)acrylic acid alkyl ester is n
-Claim 1 which is butyl acrylate
The toner according to any one of items 1 to 4.