JPH0895294A - Toner for developing electrostatic charge image - Google Patents

Abstract

PURPOSE: To enable fixation at a low temp., to ensure satisfactory transferability and to form an image having high image quality by making a sticky resin from a styrene-acrylic copolymer contg. an acrylic monomer having a long chain alkyl group and a multifunctional acrylic monomer. CONSTITUTION: In this toner consisting essentially of a bonding resin and a colorant, the bonding resin is a styrene-acrylic copolymer contg. an acrylic monomer having a long chain alkyl group and a multifunctional acrylic monomer. Monomers forming the bonding resin may be selected from among styrenes such as styrene and o-methylstyrene, ethylenically unsatd. monoolefins such as ethylene and propylene, vinyl halides such as vinyl chloride and vinylidene chloride, vinyl esters such as vinyl acetate and vinyl propionate and d-methylene aliphatic monocarboxylic esters such as methyl acrylate and ethyl acrylate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner for developing an electrostatic charge image useful for developing an electrostatic charge image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method or the like, and more specifically, an electrostatic charge image developing toner. The present invention relates to a binder resin used for toner for toner.

[0002]

2. Description of the Related Art Generally, in electrophotography, electrostatic recording, etc., in order to develop an electrostatic latent image formed on a latent image carrier made of a photoconductive photoreceptor or a dielectric,
Need to develop using toner that is made into a thin layer on a toner supply roller such as a developing sleeve with a blade and is appropriately charged and finely powdered, or mixed with a carrier and appropriately charged and finely powdered. The toner image is transferred to a transfer material such as paper according to the above, and then fixed by heating pressure, solvent vapor or the like to obtain a copy. Although there are various toner fixing methods applied to these developing methods, the heat roller fixing method is widely used because of its high thermal efficiency and high-speed fixing capability. When high-speed fixing is performed by such a heat fixing method, the toner is required to have good low-temperature fixing property (or low fixing lower limit temperature). For this reason, when a low-softening resin is contained as the binder resin, a part of the toner image adheres to the surface of the heat roller during fixing, and this is transferred to the copy paper to cause scumming. A so-called hot offset phenomenon or a so-called winding phenomenon (especially when the temperature of the heat roller is low), which is a phenomenon in which the copy paper adheres to the surface of the heat roller and winds around, tends to occur. Therefore, as means for preventing these phenomena, JP-A-51-143333, JP-A-57-148752,
JP-A-58-97056, JP-A-60-247250
JP-A No. 2004-242242 proposes to add solid silicone varnish, higher fatty acid, various higher alcohol waxes, etc. as a release agent, but all of them have sufficient offset resistance and wrapping resistance while maintaining good low temperature fixing property. There is no known gender. Specifically, conventional polyolefin waxes such as low-molecular-weight polyethylene and low-molecular-weight polypropylene have good offset resistance, but their low-temperature fixability is not sufficient, and plant waxes such as carnauba wax and candelilla wax are offset-resistant. Property and low temperature fixability are good, but the wrapping resistance is not sufficient, and solid silicone varnish, solid silicone oil, amide wax, higher fatty acid, higher alcohol and montanic acid wax have good low temperature fixability, Offset resistance and winding resistance are not sufficient. Moreover, the conventional release materials have many so-called filming and spent in which the release agent is released from the toner and adheres to the photoconductor and the carrier during development, and it is difficult to form a high-quality image stably for a long period of time. there were. In addition, for the purpose of lowering the fixing temperature, at the same time, in many cases, the composition, thermal characteristics, molecular weight distribution, etc. are specified for the purpose of imparting offset resistance and blocking resistance. For example, JP-A-3-139663 (toner softening temperature), JP-A-3-152558 (molecular weight distribution), JP-A-3-145654 (binder resin crosslinking agent), JP-A-3-206465 (binder resin). Composition), JP-A-3-219262 (viscoelastic property), JP-A-3-188468 (polymer acid value / hydroxyl group value), JP-A-3-203748, JP-A-3-2292.
No. 64 (acid value of polyester), JP-A-3-23175.
7, JP-A-4-353866, JP-A-5-1004
77 (viscoelastic property), JP-A-4-20512, 4-23816, JP-A-4-23817, and JP-A-4-5.
No. 0216 (composition of styrene-acrylic block copolymer), JP-A-4-26858 and JP-A-4-817.
69, JP-A-4-81770 (composition of block or graft copolymer of crystalline polyester and vinyl copolymer), JP-A-4-81863 (peak of molecular weight distribution), JP-A-4-190242 (molecular weight). Combination of distribution and fixing method), JP-A-4-254863 (molecular weight of polyester and styrene / acrylic polymer), JP-A-4-264559, JP-A-4-264560, JP-A-4-274253, JP-A-5. -19531, JP-A-5-188638 (molecular weight distribution), JP-A-4-27
No. 7755 (composition of block copolymer), JP-A-4-3
No. 09962 (composition of ionomer) and the like are mentioned, but those disclosed therein are not yet sufficient. Further, a photo-disintegrating capsule of JP-A-60-31146, an exothermic amplifying material of JP-A-62-148969, a capsule toner having a thermotropic liquid crystal polymer shell of JP-A-63-281168, JP-A-1. -1490
No. 62 using volume expansion of capsules by light irradiation, crosslinked thermotropic liquid crystal polymer of JP-A-2-251971, toner containing heat-generating substance of JP-A-3-118550, cyclohexane derivative of JP-A-4-250460, Bisphenol F type epoxy resin described in JP-A-4-291355, near-infrared light absorbing dye and ethylenically unsaturated compound (cured by near-infrared light) disclosed in JP-A-4-329551, JP-A-4-100475 and JP-A-4-100475 4-1004
No. 76 shows a thermally decomposable resin using an azo high-molecular weight initiator, and JP-A No. 5-173364 shows a resin using a novel material such as a cyclohexanone type ketone resin, but these are not sufficient. Further, conventionally, the energy saving of the fixing process has been studied by the above-mentioned technology and the resin having a low softening temperature (polyester etc.), but in the future, low temperature toner fixing for further energy saving becomes important. For that purpose, it is not enough to use the conventional techniques together, and in recent years, energy saving of OA equipment has been sought and improvement of the fixing process, which accounts for most of the power consumption in copying machines and printers, has been demanded.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and enables low temperature fixing without causing an offset phenomenon or a winding phenomenon around a heat roller at the time of fixing, and developing It is an object of the present invention to provide a toner for an electrostatic image developer, which has less filming, exhibits good transferability, and can obtain a high-quality image.

[0004]

The constitution of the toner for developing an electrostatic charge image of the present invention will be described below. The first invention of the present case relates to a toner for developing an electrostatic charge image containing a binder resin and a colorant as main components, wherein the binder resin is a styrene acrylic copolymer and an acrylic monomer having a long chain alkyl group and a polyfunctional acrylic resin. 2. A toner for developing an electrostatic charge image, comprising a series monomer, and the second invention is characterized in that the alkyl group of the acrylic monomer having a long chain alkyl group has 12 or more carbon atoms. The toner for developing an electrostatic charge image according to the third aspect, and the third invention, the toner for developing an electrostatic charge image according to claim 1, wherein the polyfunctional acrylic monomer is represented by the following general formula (I):

[0005]

[Chemical 1] (In the formula, n represents an integer of 4 to 10.)

A fourth invention is the toner for developing an electrostatic charge image according to claim 1, wherein the binder resin is polymerized by a dispersion polymerization method. A fifth invention is the toner for developing an electrostatic charge image according to claim 1, wherein the binder resin has a microphase-separated structure of 1 μm or less, and by using these toners, the present invention can be obtained. The purpose of can be achieved. There is a strong demand for low-temperature fixability as a toner property, and it is a necessary condition to improve this point in toner design. However, it has been very difficult to achieve both hot offset prevention and heat resistant storage stability for the fixing roller with the conventional styrene-acrylic copolymer. Therefore, recently, attempts have been made to solve the above problems by using a polyester resin instead of the above polymer, but it is still not sufficient. In the present invention, it is possible to prevent such problems of conventional toners from being wound around the fixing roller, and to achieve both hot offset prevention and heat resistant storage stability. Furthermore, the heat-resistant storage stability could be improved by using a polyfunctional monomer having a specific structure. Further, by using an acrylic monomer having a long-chain alkyl group having a specific structure (the number of carbon atoms of the alkyl group is preferably 12 or more, more preferably 18 or more), low temperature fixing property and prevention of wrapping around the fixing roller can be obtained. Could be improved. Further, by the dispersion polymerization method, it was possible to achieve both better low temperature fixing and prevention of hot offset.

The binder resin used in the toner of the present invention can be obtained by a polymerization method such as a suspension polymerization method, but it is preferable to use a resin polymerized by a dispersion polymerization method. It is considered that this is because the phase separation structure in the binder resin polymerized by the dispersion polymerization method is very small and the softening temperature can be sufficiently lowered. In particular, the microphase-separated structure in the binder resin of the present invention is preferably a domain structure of 1 μm or less, and the phase-separated structure of 1 μm or less can achieve very good low-temperature fixing. The toner particles for developing an electrostatic image used in the present invention can be produced by the method described below. First, a polymeric dispersant such as polyvinylpyrrolidone is completely dissolved in a hydrophilic organic solvent such as methanol, and then a styrene monomer, an acrylic monomer, stearyl acrylate, a chain transfer agent, and an acrylic monomer having a long-chain alkyl group. , Mix the polyfunctional acrylate,
Polymerization was initiated by adding a polymerization initiator (AIBN) at about 60 ° C., polymerized for 24 hours, washed with a water / methanol mixed solution, solid-liquid separated by suction filtration, and finally dried to obtain polymer particles. Is obtained. The toner of the present invention can be obtained by dyeing this with a dye.

Examples of the monomer forming the binder resin used in the present invention include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene and p-methylstyrene. n-butyl styrene, p-tert-butyl styrene, pn
-Hexyl styrene, pn-octyl styrene, p-
n-nonylstyrene, pn-decylstyrene, pn
-Styrenes such as dodecylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene; etc .; ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, isobutylene, chlorination Vinyl halides such as vinyl, vinylidene chloride, vinyl bromine and vinyl fluoride; vinyl acetates such as vinyl acetate, vinyl propionate and vinyl acetate, methyl acrylate, ethyl acrylate, -n-butyl acrylate, methacryl Α-Methylene aliphatic monocarboxylic acid esters such as methyl acidate and ethyl methacrylate, vinyl ethers such as vinyl methyl ether, vinyl ketones such as vinyl methyl ketone, N-vinylpyrrole, N-vinylcarbazole, N-vinyl Indole, N-vinylpyrrolid , It can be exemplified N- vinyl compounds such like. These monomers can be used alone or in combination of two or more kinds, and are not limited to the monomers shown here.

Further, conventionally known additives such as colorants and charge control agents can be added to the toner of the present invention. For example, metal chelate dyes such as oil black, nigrosine dyes, metal-containing dyes, aniline dyes, Calco oil blue,
Examples include chrome yellow, ultramarine blue, methylene blue chloride, phthalocyanine blue, rose bengal, and other dyes and pigments.

Further, a fluidizing agent may be added, and for example, known ones such as inorganic oxides such as SiO ₂ and TiO ₂ whose surfaces are hydrophobized, inorganic fine particles such as SiC, metallic soap of zinc stearate and the like are used. be able to.

[0011]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto.

Example 1 First, 30 ml of methanol was placed in a 500 ml three-necked flask equipped with a stirring blade and a condenser.
0 g and 30 g of ion-exchanged water were added, and 6.4 g of a polymer dispersant Gantret (copolymer of methyl vinyl ether and maleic anhydride: average molecular weight 40,000) was added little by little with stirring to completely dissolve it. Further, the following ingredients were added and completely dissolved. Styrene 25.6 g n-Butyl methacrylate 6.4 g Stearyl acrylate 3.0 g 2,2'-Azobisisobutyronitrile 0.2 g Dodecyl mercaptan 0.2 g Polyfunctional acrylic monomer represented by the following structural formula (A) 0.3 g

[0013]

[Chemical 2] (In the formula, n = 4)

While stirring these, the inside of the flask was purged with nitrogen gas and left for 1 hour. Next 60 ℃ ± 0.1 ℃
Polymerization was started while stirring at a stirring speed of 200 rpm in the constant temperature water bath. The liquid started to become cloudy after 15 minutes from heating, and was a cloudy and stable dispersion even after polymerization for 20 hours. The polymerization rate of the dispersion was 85%. When the dispersion obtained 24 hours after the initiation of polymerization was cooled and centrifuged at 2000 rpm with a centrifuge, the polymer particles were completely settled and the upper liquid was transparent. The supernatant was removed, 200 g of methanol was newly added, and the mixture was washed by stirring for 1 hour, then centrifuged and washed with methanol, and the mixture was filtered. The product separated by filtration was dried under reduced pressure at 50 ° C. for 24 hours to give a white powder of styrene / n with a yield of 98%.
-Butyl methacrylate-based copolymer particles were obtained. The volume average particle diameter Dv of the obtained polymer particles was 5.2 μm and the number average particle diameter Dp was 4.9 μm. When the cross section of the polymer particles was observed with a TEM, a microphase-separated structure of 0.1 μm was observed. Next, separate methanol 200g
1.0 g of Oil Black 803 (manufactured by Orient Chemical Co., Ltd.) was heated and dissolved therein, cooled, and then filtered with a 1 μm filter to prepare a dye solution. To the dye solution, 24 g of the polymer particles were added and dispersed, and the mixture was heated and stirred at 50 ° C. for 1 hour for dyeing, and then the dyed resin particle dispersion was cooled to room temperature and filtered to obtain fine colored resin particles. This at room temperature 24
After vacuum drying for an hour, it was mixed with 1.5 parts of silica to obtain a toner of the present invention. Next, 3 parts of the toner of the present invention and 97 parts of a ferrite carrier were mixed to prepare a developer, an image was formed on a commercially available electrophotographic copying machine (FT8200 manufactured by Ricoh Company), and fixing was carried out at 150 ° C. An image was obtained. The obtained images were of good quality not only at the beginning of copying but also after copying 100,000 sheets. Also, in a high temperature and high humidity environment (35 ° C, 90% RH), in a low temperature and low humidity environment (10 ° C, 1%
Even with 5% RH), an image similar to that copied in a room temperature and normal humidity environment could be obtained, and filming on the photoreceptor was not observed. In addition, the obtained image at 3
It was left for a day, but no blocking occurred.

Example 2 Colored resin fine particles were obtained in the same manner as in Example 1 except that the amount of the polyfunctional acrylic monomer represented by the structural formula (A) was changed to 0.5 g. It was The obtained particles have a volume average particle diameter Dv = 4.
It was 6 μm and the number average particle diameter Dp was 4.2 μm. When the cross section of the particles was observed by TEM, a microphase-separated structure of 0.2 μm was observed. This was vacuum dried at room temperature for 24 hours and then mixed with 1.5 parts of silica to obtain a toner of the present invention. Thereafter, a developer was prepared in the same manner as in Example 1, then an image was formed and fixing was carried out at 150 ° C., and a good image was obtained. The obtained images were of good quality not only at the beginning of copying but also after copying 100,000 sheets. Further, even under a high temperature and high humidity environment (35 ° C., 90% RH) and a low temperature and low humidity environment (10 ° C., 15% RH), it is possible to obtain an image similar to that copied in a normal temperature and normal humidity environment. No filming was found. Further, the obtained image was left at 50 ° C. for 3 days, but no blocking occurred.

Example 3 Colored resin fine particles were obtained by the same method as in Example 1 except that the monomer component of the copolymer, stearyl acrylate, was changed to behenyl acrylate. The obtained particles have a volume average particle diameter Dv =
The average particle diameter Dp was 5.9 μm and the number average particle diameter Dp was 5.7 μm.
In addition, when the cross section of the particle was observed by TEM, it was 0.34 μm.
The microphase-separated structure was observed. This was vacuum dried at room temperature for 24 hours and then mixed with 1.5 parts of silica to obtain a toner of the present invention. Thereafter, a developer was prepared in the same manner as in Example 1, then an image was formed and fixing was carried out at 150 ° C., and a good image was obtained. The obtained images were of good quality not only at the beginning of copying but also after copying 100,000 sheets. Further, even under a high temperature and high humidity environment (35 ° C., 90% RH) and a low temperature and low humidity environment (10 ° C., 15% RH), it is possible to obtain an image similar to that copied in a normal temperature and normal humidity environment. No filming was found. Further, the obtained image was left at 50 ° C. for 3 days, but no blocking occurred.

Example 4 Colored resin fine particles were obtained by polymerizing in the same manner as in Example 1 except that the polyfunctional acrylic monomer was replaced by a monomer represented by the following structural formula (B).

[Chemical 3] (In the formula, n = 6) The obtained particles had a volume average particle diameter Dv = 4.9 μm and a number average particle diameter Dp = 4.7 μm. When the cross section of the obtained particles was observed by TEM, a microphase-separated structure of 0.14 μm was observed. After vacuum drying this at room temperature for 24 hours,
The toner of the present invention was obtained by mixing with 1.5 parts of silica. Thereafter, a developer was prepared in the same manner as in Example 1, then an image was formed and fixing was carried out at 150 ° C., and a good image was obtained. The obtained images were of good quality not only at the beginning of copying but also after copying 100,000 sheets. Also, under high temperature and high humidity environment (35 ° C, 90% RH), under low temperature and low humidity environment (1
Even at 0 ° C. and 15% RH), it was possible to obtain the same image as that copied in a normal temperature and normal humidity environment, and filming on the photoreceptor was not observed. In addition, the obtained image is 5
No blocking occurred when left at 0 ° C for 3 days.

[Comparative Example 1] The same procedure as in Example 1 was carried out except that stearyl acrylate and the polyfunctional acrylate-based monomer represented by the structural formula (A) were not used in Example 1 to obtain resin particles for comparison. It was The obtained particles were post-treated and washed in the same manner as in Example 1. The material separated by filtration was dried under reduced pressure at 50 ° C. for 24 hours to obtain white powder of styrene / n-butyl methacrylate copolymer particles in a yield of 93%. The obtained particles have a volume average particle diameter Dv =
The particle size was 5.0 μm and the number average particle diameter Dp was 4.7 μm.
Next, the particles were colored in the same manner as in Example 1, and the cross section of the obtained colored particles was observed by TEM, but no phase-separated structure was observed. Next, a developer was prepared in the same manner as in Example 1 to form an image having a solid portion at the tip and the image was fixed at 150 ° C. When the fixing roller was wound.

[0019]

According to the present invention, it is possible to prevent winding around the fixing roller while satisfying the excellent low-temperature fixability and to achieve both hot offset prevention and heat resistant storage stability. Furthermore, the heat-resistant storage stability could be improved by using a polyfunctional monomer having a specific structure. Further, by using an acrylic monomer having a long-chain alkyl group having a specific structure (the number of carbon atoms of the alkyl group is preferably 12 or more, more preferably 18 or more), low temperature fixing property and prevention of wrapping around the fixing roller can be obtained. Could be improved. Further, by the dispersion polymerization method, it was possible to achieve both better low temperature fixing and prevention of hot offset.

Claims (5)

[Claims] 1. A toner for developing an electrostatic charge image comprising a binder resin and a colorant as main components, wherein the binder resin is a styrene acrylic copolymer, an acrylic monomer having a long-chain alkyl group and a polyfunctional acrylic A toner for developing an electrostatic charge image, which comprises a monomer. 2. The toner for developing an electrostatic charge image according to claim 1, wherein the alkyl group of the acrylic monomer having a long chain alkyl group has 12 or more carbon atoms. 3. The toner for developing an electrostatic charge image according to claim 1, wherein the polyfunctional acrylic monomer is represented by the following general formula (I). [Chemical 1] (In the formula, n represents an integer of 4 to 10.) 4. The toner for developing an electrostatic charge image according to claim 1, wherein the binder resin is polymerized by a dispersion polymerization method. 5. The toner for developing an electrostatic charge image according to claim 1, wherein the binder resin has a micro phase separation structure of 1 μm or less.