JPH0251175B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developer used in electrophotography, electrostatic printing, etc., and particularly to a dry developer suitable for heat fixing. Conventionally, as an electrophotographic method, U.S. Patent No. 2297691
Specification of No. 42-23910 and Special Publication No. 1973
Although a number of methods are known, such as those described in Japanese Patent Application No. 24748, in general, a photoconductive substance is used to form an electrical latent image on a photoreceptor by various means, and then the latent image is The toner image is developed using toner, the toner image is transferred to a transfer material such as paper as required, and then fixed by heat or pressure to obtain a copy. Furthermore, various developing methods are known in which an electrical latent image is visualized using toner. For example, the magnetic brush method described in U.S. Pat. No. 2,874,063, the cascade development method described in U.S. Pat. Development methods such as the development method are known.
As toners used in these developing methods, fine powders in which dyes and pigments are dispersed in natural or synthetic resins have conventionally been used. Furthermore, the third
It is also known to use developing fine powders to which substances have been added for various purposes. The developed toner image is transferred and fixed onto a transfer material such as paper, if necessary. Methods for fixing toner images include heating and melting the toner using a heater or heated roller to fuse and solidify it to the support, softening or dissolving the binder resin of the toner with an organic solvent, and fixing it to the support, and applying pressure. A method of fixing toner on a support by using a method is known. Toner materials are selected to be suitable for each fixing method, and toners used for specific fixing methods generally cannot be used for other fixing methods. especially,
It is almost impossible to transfer the toner used in the conventionally widely used heat fusion fixing method using a heater to a hot roller fixing method, a solvent fixing method, a pressure fixing method, or the like. Therefore, toners suitable for each fixing method are being researched and developed. Various magnetic recording methods are also known in which a magnetic latent image is formed and developed with magnetic toner. Various methods and devices have been developed for the process of fixing toner images on paper, etc., but the most common method currently is the so-called hot roll fixing method, which applies heat and pressure at the same time. In this method, the toner image is fixed on the image-receiving sheet by bringing the image-receiving sheet carrying the toner image into contact with a heated roller. However, when such a fixing method is used, problems such as so-called offset occur with conventional toner. Offset is an undesirable development in which a portion of the toner carried on the image receiving sheet is transferred to the roller surface. As stated in the Special Publication No. 51-23354,
Such an offset phenomenon is likely to occur when a low molecular weight resin is used. Therefore, as stated in the same publication, it is thought that the offset phenomenon can be prevented to some extent by using a crosslinked resin, but of course, simply using a crosslinked resin will not cause the fixation As the temperature rises, the problem of low temperature offset occurs in the unfixed area. The roller that comes into contact with the toner image usually has at least a surface layer formed of silicone rubber or fluororesin, which has good releasability, to prevent offset and fatigue of the roller surface. For this reason, there is also a method of applying a mold release agent oil such as silicone oil. However, the method of applying oil has problems such as that the fixing device becomes complicated due to the provision of the oil application system and that the evaporation of the oil causes discomfort to the user. Therefore, it is not desirable to try to prevent offset by coating with oil, but rather the development of a toner with good offset resistance over a wide fixing temperature range is currently desired. Of course, in addition to fixing properties, toners also need to be excellent in blocking resistance, developing properties, transferability, cleaning properties, etc. However, conventional toners suffer from the following defects. He had one or more. That is, many toners that are easily melted by heating tend to cake or aggregate during storage or in a copying machine. Many toners lose their triboelectric properties and flowability due to environmental humidity changes. In addition, with many toners, the image density obtained changes due to mutual deterioration of the toner, carrier particles, and photosensitive plate due to collisions between toner particles and carrier particles and their contact with the photosensitive plate surface due to repeated development due to continuous use. , or the background density increases, reducing the quality of the copy. Therefore, there is a need for a toner that has excellent toner properties and is suitable for hot roller fixing. More recently, high-speed fixing has been sought to improve the efficiency of copying operations. In order to reduce the fixing speed in conventional heat fixing methods, attempts have been made to lower the softening point of the toner binder resin to facilitate heat fixing. Troubles such as agglomeration and blocking occur. In this way, it is suitable for faster heat roller fusing,
Moreover, there is a strong desire for a toner that is free from roller offset and has excellent toner properties such as aggregation and blocking. Conventionally, it has been considered to make toner into a capsule type simply to increase the heat fixing speed, or to reduce the heat source energy while increasing the speed. Fusing toners have been proposed. This type of capsule toner uses a low melting point component that is more easily melted by heat as the core material, and a component that has a high melting point and has properties such as chargeability and fluidity required for a toner as the shell material. For example, in Japanese Patent Publication No. 49-1588, there are examples of polystyrene capsules using wax as a core material or polystyrene capsules using an aqueous solution as a core material. However, none of these methods takes into account the recent high-speed fixing with hot rolls, and therefore suffers from severe roller offset, and is therefore impractical. As described above, conventional heat-setting capsule toners cannot avoid the problem of roller offset. As a result of our research into materials that have good hot roll high-speed fixing properties and excellent offset resistance, we found that
It has been discovered that a combination of an amorphous polyester resin and an aliphatic amine or its derivative satisfies these requirements. The aliphatic amine mixed with the polyester causes some reaction with the polyester during processes such as kneading, which greatly changes the thermal properties of the polyester. This change resembles a crosslinking reaction of polyester,
Along with this, the offset resistance of polyester is improved without impairing its fixing properties. However, these characteristics of the mixture of polyester and amine are still insufficient to achieve both better low-temperature fixing and blocking, and there are still obstacles. Therefore, we have conducted extensive studies to take advantage of the characteristics of these resins and to overcome the toner blocking and caking that would occur if a conventional simple pulverization method toner was used for high-speed fixing. ,
We have found that it is essential to create a capsule structure using this type of material as the core material. In other words, low-temperature fixing properties and offset resistance are achieved through a mixed thermal reaction of amorphous polyester and aliphatic amine, and the slight drawback of this material's blocking properties is compensated by the capsule structure. High-speed roll fixing, offset resistance,
It has been found that various toner properties such as blocking resistance, caking resistance, developability, and durability can be satisfied, leading to the present invention. An object of the present invention is to provide a heat fixable toner that solves the above-mentioned problems. A further object of the present invention is to provide a toner for hot roller fixing that has particularly good fixing properties and offset resistance. A further object of the present invention is to provide a toner for hot roller fixing that has good chargeability and always exhibits stable chargeability during use, and provides clear and fog-free images. A further object of the present invention is to provide a toner for hot roller fixing that has excellent fluidity, does not cause aggregation, and has excellent impact resistance. A further object of the present invention is to provide a toner for thermal roller fixing that has less deposits on the surface of a toner holding member or photoreceptor. A further object of the present invention is to provide a magnetic toner which, when used as a magnetic developer, exhibits good and uniform magnetism and can be fixed by a hot roller. The above object of the present invention is achieved by providing a toner with a capsule structure in which the core material is a material having high-speed heat fixing properties and offset prevention properties. Specifically, the present invention relates to an electrostatic image developer used for heat fixing that contains a capsule toner in which the core particle surface of a heat fixable material whose main components are a binder resin and a colorant is coated with a thermoplastic resin. In the developer for
The binder resin has a glass transition temperature of 60°C or less, and a glass transition temperature of 50°C or less.
Amorphous polyester having a softening point of ~110°C and an acid value of 10 to 150, and 1/
500 to 1/5 weight of aliphatic amine or its derivative, and the thermoplastic resin contains 0.2 to 10 mol% of organic acid monomer, styrene or its derivative, acrylic ester, methacrylic ester, and maleic ester. A vinyl copolymer resin with two or more monomers selected from the group consisting of
Glass transition temperature over 100~150℃, softening point 15
The present invention relates to a developer for developing electrostatic images, which is a vinyl copolymer resin having an Mw of 10,000 or more and a Mw/Mn of 5 or more. In other words, the present invention is characterized by achieving high-speed heat fixing properties and offset resistance using a special core material.
At the same time, the shell material has a heat-fixable toner structure with a capsule structure that achieves general toner properties such as cohesiveness, blocking property, and developability. In the heat-fixable toner having a capsule structure related to the present invention, a core material that cannot be used alone due to its properties such as blocking and cohesive properties is used as a core material.
A material with low Tg and good offset resistance is used to share most of the functions of heat roller fixing, and as a shell material, it maintains toner characteristics such as developability and storage stability of dry toner as before. Alternatively, the objects of the present invention could be achieved by using a material having more than that number and making it a so-called functionally separated type. As the binder resin for the core particles used in the present invention, a specific polyester resin suitable for the purpose of the present invention is preferable. In other words, the glass transition temperature is 60℃ or less, and the softening point is 50℃.
~110℃ amorphous polyester resin as a binder for the core particles at least 50% by weight (more preferably 60% by weight)
(wt% or more) is desirable. The acid components of the polyester used in the core particles of the present invention include terephthalic acid, isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, trimellitic acid,
Aromatic polycarboxylic acids such as pyromellitic acid; P
- Aromatic oxycarboxylic acids such as (2-hydroxyethoxy)benzoic acid; aliphatic polycarboxylic acids such as maleic acid, fumaric acid, succinic acid, adipic acid, azelaic acid, and sebacic acid; 1,3-cyclohexanedicarboxylic acid, Examples include aliphatic polycarboxylic acids such as hexahydrophthalic acid and tetrahydrophthalic acid. In addition, alcohol components include ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, glycerin, trimethylolethane. , trimethylolpropane, pentaerythritol; aliphatic polyols such as 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol; ethylene oxide adducts of bisphenol A, propylene adducts of bisphenol A, etc. There are etherified diphenols. The acid component and alcohol component of the polyester used in the present invention can be arbitrarily selected as long as the combination satisfies the conditions for its amorphous glass transition temperature, but generally it has amorphous properties and a certain degree of low softening point. Therefore, it is necessary to include an asymmetric component. Furthermore, for the purpose of offset resistance, it is preferable to include trivalent or higher polycarboxylic acid and/or polyol as a component to give the polyester a suitable network structure. The polyester used in the present invention has a glass transition temperature of 60°C or less and a softening point of 50 to 110°C. If the glass transition temperature exceeds 60°C or the softening point exceeds 110°C, the softening point will become even higher when taking into account the thermal reaction with the aliphatic amine of the present invention, and excessive thermal energy will be required during heat fixing. As a result, high-speed heat fixing performance deteriorates. If the softening point is less than 50°C, offset resistance during fixing may be poor depending on the degree of reaction with aliphatic amines. Likewise, if the molecular weight is less than 2,000, the hot roller releasability will be poor and an offset phenomenon will easily occur, while if it exceeds 20,000, the softening point will increase and the heat fixing property will decrease. The aliphatic amine or its derivative used in combination with the polyester is one that can react with the terminal residue in the polyester, such as dibutylamine, tripropylamine, tributylamine, diamylamine, octadecyldimethylamine, hexadecyldimethylamine. , aliphatic amines such as beef tallow alkylpipropylene diamine, hardened tallow alkyldimethylamine, hardened beef tallow alkylpropylene diamine, or polyoxyethylene dodecylamine, polyoxyethylene octadecylamine, polyoxyethylene tallow alkylamine, polyoxyethylene tallow alkyl There are aliphatic amine derivatives such as propylene diamine. It is preferable that the toner has a high melting point and a high boiling point so that it does not volatilize during toner production or use. In the present invention, the mixing ratio of polyester and aliphatic amines is 99.8 to 80% by weight of polyester;
Aliphatic amines are 0.2 to 20% by weight, that is, the ratio of amines to polyester is 1/500 to 1/500.
5 weight ratio, more preferably 1/500 to 1/10. If the amount of amines is less than 1/500, the thermal reaction will be insufficient and the releasability of the toner from the heated roll will be poor and offset phenomenon will likely occur. If the content of amines exceeds 1/5, the thermal fluidity of the toner will be adversely affected, resulting in poor fixing such as increased fixing temperature. As the binder resin for the core particles, other known binder resins such as polyester resins, epoxy resins, styrene-acrylic resins, butyral resins, and ethylene-acrylic resins other than those of the present invention may be used as long as they do not impair the performance of the present invention.
Ethyl acrylate resin, styrene-butadiene resin, etc. can be used in combination. As the thermoplastic resin used as the wall substance material used in the present invention, those conventionally used as binders for toners can basically be used, but these are limited to some extent due to constraints on the capsule structure of the present invention. . Within this range, for example, those that can be used as aqueous suspensions, those that can be used as alkali-soluble aqueous solutions, those that can form a coating layer on core particles by known microencapsulation methods, or those that can be used during encapsulation. There are some that can be formed by reaction. Water-based suspension resins must have a minimum film-forming temperature near the softening point of the core particles or preferably at least 30°C lower than that, and have good wettability and adhesion to the core particles. It is necessary to maintain the durability of the toner when forming the outer wall, it must be uniformly coated, not brittle, and not sticky, it must maintain image forming ability, it must have appropriate electrical resistance (insulation), triboelectrification, etc. characteristics are required. Such resin components include two or more monomers arbitrarily selected from monomers such as acrylic esters, methacrylic esters, styrene or its derivatives, vinyl acetate, maleic esters, etc. 0.2 to 10 mol% acrylic acid,
The main component is a copolymer resin obtained by emulsion polymerization of organic acid monomers such as methacrylic acid, maleic acid, itaconic acid, and crotonic acid, that is, 60 mol% of this copolymer component in the resin content. These include the above. In addition, two or more monomers arbitrarily selected from monomers such as styrene or its derivatives, acrylic esters, methacrylic esters, maleic esters, etc. can be used as an alkali-soluble aqueous solution. On the other hand, there are products in which organic acid monomers such as acrylic acid, maleic acid, itaconic acid, and crotonic acid are copolymerized in an amount that gives an acid value of about 40 to 200 after polymerization. These thermoplastic resins have a glass transition temperature of 55°C or higher and a softening point of 100 to 150°C. If the glass transition temperature is less than 55° C., the resulting toner will cause blocking during storage, rendering it impractical.
Furthermore, if the softening point is below 100°C, offset will easily occur during heat fixing. Furthermore, if the softening point exceeds 150°C, the heat fixability of the core material will be significantly impaired. The weight average molecular weight Mw needs to be 150,000 or more from the point of view of preventing thermal roller offset, and from the same point of view
It is desirable that Mw/Mn is 5 or more. When Mw is less than 150,000 and Mw/Mn is less than 5, the heat-molten vinyl polymer has poor offset resistance. In the capsule toner of the present invention, a charge control agent, a coloring agent, and a fluidity modifier may be added to one or both of the core material and the outer shell as necessary. The agent may be used by being mixed with the toner (externally added). Examples of this charge control agent include metal-containing dyes and nigrosine, and conventionally known dyes and pigments can be used as colorants.
Examples of fluidity modifiers include colloidal silica and fatty acid metal salts. Furthermore, if it is desired to obtain a magnetic toner, magnetic fine particles may be added to the toner. The magnetic substance may be any material that exhibits magnetism or can be magnetized, such as fine metal powders such as iron, manganese, nickel, cobalt, and chromium, various ferrites, alloys and compounds of manganese, and other ferromagnetic alloys. Conventionally known magnetic materials can be used. These magnetic fine particles may be added to either the core material or the shell material, but in the case of obtaining an insulating toner, it is preferable to add them to the core material. Furthermore, polyolefins such as low molecular weight polyethylene, low molecular weight polypropylene, etc. may be added to the core material and/or the shell material in order to improve the releasability from the heat fixing roll. In the present invention, the method for obtaining core particles is as follows:
A known dry toner manufacturing method can be applied as is.
For example, the most common method is to pre-mix polyester resin and other compounds into fine particles, homogeneously mix them by hot melt kneading, and then obtain core particles of a constant particle size using air jet pulverization, wind classifier, etc. be. Moreover, core particles of a constant particle size can also be obtained by preparing an organic solvent solution of a polyester resin, uniformly dispersing the compound, and then spray-drying and granulating it using a spray dryer. In the present invention, the spray drying method is preferred as the encapsulation method, but depending on the material used as the wall material, phase separation methods, air suspension coating methods, etc. can be used. EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but these are not intended to limit the present invention. Further, all parts in the examples are parts by weight.
In addition, each physical property of the resin was measured by the following method. Glass transition temperature - heating rate 16 by differential scanning calorimeter (PerkinElmer Model DSC-1B)
Measured in °C/min. Softening point - Based on JIS K2531 return ball softening point test. Number average molecular weight (weight average molecular weight) - Measured by GPC measurement based on polystyrene standards. Production Example 1 Put 700 parts of polyethylene oxide adduct of bisphenol A and 7 parts of glycerin into a four-necked flask, set a stirrer, condenser, thermometer, and gas inlet tube, and place it in a mantle heater. After purging the inside of the reaction vessel with nitrogen gas and bringing the temperature of the contents to 50 to 60°C, 270 parts of fumaric acid and 0.4 parts of hydroquinone are added, and the mixture is stirred and heated to 210°C. After about 5 hours have passed while continuously removing the reaction water, the reaction is monitored by measuring the acid value every hour to check the end point of the reaction. After continuing the reaction until the oxidation is approximately 25, the resin is cooled to room temperature. The resin thus obtained had a Tg of 52°C, a softening point of 110°C, and an acid value of 45. Production example 2 Put 650% terephthanic acid, 200% sebacic acid, 140% isophthalic acid, 650% ethylene glycol, and 350% neopentyl glycol into a flask and heat at 180 to 220℃.
The reaction was carried out for an additional 230 hr, and then the system was depressurized for an additional 230 hr.
The reaction was carried out at ℃ for 1 hour. The resulting resin has a Tg30
℃, the softening point was 100℃, and the acid value was 73. Production Example 3 After charging 490 parts of terephthanic acid, 180 parts of trimellitic acid, 640 parts of propylene glycol, 220 parts of neopentyl glycol, and 25 parts of trimethylolpropane into a flask and carrying out an esterification reaction at 210°C to 230°C for 5 hours. , add 266 parts of isophthalic acid,
The reaction was carried out for 6 hours at 230°C in a nitrogen stream. The obtained polyester has a Tg of 46℃, a softening point of 57℃, and an acid value.
It was 140. Production example 4 Fill a flask with 500% terephthanic acid, 100% ethylene glycol, 420% neopentyl glycol, 50% trimethylolpropane, and 270% isophthalic acid.
Heat and stir to ℃. Then dibutyltin oxide
Add 0.6 and heat to 220°C to react for about 6 hours. The obtained polyester has a Tg of 50℃ and a softening point of 86.
℃, and the acid value was 96. Production Example 5 According to the same method as Production Example 1, terephthalic acid
400 parts, isophthalic acid 100 parts, ethylene glycol
Put 280 parts and 120 parts of neopentyl glycol into a flask, and heat and stir at 60°C. Next, the mixture is heated to about 220°C and the reaction is carried out for about 6 hours. The Tg of the polyester obtained by cooling after the reaction is 65℃, and the softening point is
It was 135℃. Production example 6 580 parts of dimethyl terephthalate, 300 parts of 1,2 propanediol, 4 parts of trimethylolpropane,
into the flask. After heating the mixture to about 80 °C and adding 1.5 parts of tetrabutyl titanate,
Gradually heat to about 200°C over about 6 hours.
After reducing the pressure of the system and removing the distillate, the system was further heated under reduced pressure for 6 hrs.
The reaction is completed by heating for a certain period of time. The resulting polyester had a Tg of about 80°C and a softening point of about 95°C. Example 1 100 parts of polyester (Production Example 1), 2 parts of hardened beef tallow alkylpropylene diamine, 70 parts of magnetic powder (Magnetite EPH-1000 manufactured by Toda Industries), low molecular weight polypropylene (Viscol manufactured by Sanyo Chemical Industries)
A mixture consisting of 660 parts (P) was heated and kneaded with a roll. During heating and kneading, it was confirmed that the viscosity of the kneaded product gradually increased. After cooling this, 1-2
mm coarsely crushed material, further finely pulverized with a jet mill and classified with a wind classifier, and the average
Core material particles of around 12μ were obtained. Separately, a styrene/butyl methacrylate/butyl acrylate/acrylic acid copolymer emulsion (acrylic acid 3 mol %, solid content 40) was prepared. The glass transition temperature of the constituent resin of this emulsion is 70
℃, the softening point was 140℃, Mw was 230,000, and Mw/Mn was 6.3. 58 parts of the core material for 20 parts of this emulsion.
Part, metal complex salt (Orient Chemical, Bontron E
-81) Add 0.4 parts and 240 parts of water, mix and disperse well while avoiding foaming, and then spray dry with a spray dryer at an inlet temperature of 160°C and an outlet temperature of 90°C. A crosslinked resin coating layer mainly composed of the emulsion-constituting copolymer was provided around the core material particles. Colloidal silica (Aerosil R-972) was added to the capsule toner thus obtained.
When a copying test was carried out by adding the above-mentioned material to an electrophotographic copying machine (manufactured by Canon, NP-400RE) using a one-component development method, sufficient image density and development durability were obtained. In addition, in order to examine the thermal fixability in detail, we prepared a separate fixing unit for the copying machine and used this separate fixing unit to fix an unfixed image on a separately prepared transfer paper, and no offset phenomenon occurred over a wide temperature range. The fixing properties were also excellent. Furthermore, when this capsule toner was left in an atmosphere of 50℃ for a long time,
No blotting or caking was observed. Example 2 Another example of the polyester of Example 1 (Production Example 2)
Next, a capsule toner was obtained in the same manner as in Example 1 except that the amine still used was replaced with polyoxyethylene dodecylamine. Its performance was as shown in Table 1. Example 3 A capsule toner was obtained in the same manner as in Example 1, except that 100 parts of polyester, Production Example 3, and 1 part of polyoxyethylene dodecylamine were used as the amine. Its performance was as shown in Table 1. Comparative Example 1 A capsule toner was obtained in the same manner as in Example 1 except that the polyester of Production Example 5 was used and the amine was polyoxyethylene dodecylamine. This product had a high fixing point as shown in Table 1, and poor fixing occurred. Comparative Example 2 A mixture consisting of 100 parts of the polyester of Production Example 2, 0.5 parts of polyoxyethylene dodecylamine, 70 parts of magnetic powder (Magnetite EPT-1000 manufactured by Toda Industries), and 5 parts of low molecular weight polyethylene was heated and kneaded with a roll, and after cooling. After pulverizing with a speed mill and a jet mill, the powder was classified to obtain a magnetic toner having an average size of about 12 μm. Colloidal silica (Aerosil R-
972) and supplied to a one-component development type electrophotographic copying machine (Canon NP-201 modified).
When a copying test was carried out, satisfactory images were obtained. Further, the results of tests using a separately prepared hot roll fixing tester showed that no offset phenomenon occurred over a wide temperature range, and the fixing properties were excellent. However, when this toner was left in an atmosphere at 45°C, it easily caused blocking. Comparative Example 3 A magnetic toner was obtained in the same manner as in Comparative Example 2 using a mixture consisting of 100 parts of the polyester of Production Example 2, 70 parts of magnetic powder (Magnetite EPT-1000 manufactured by Toda Kogyo), and 5 parts of low molecular weight polyethylene. When colloidal silica was added to this product and it was subjected to one-component development, the developability was sufficient. However, during the heat roll fixing process, offset is severe and there is no temperature range in which fixing and non-offset are compatible. Additionally, this toner easily caused blocking during a 45°C storage test. Example 4 A capsule toner was obtained in the same manner as in Example 1 except that the polyester of Production Example 4 and hexadecylamine were used as the amine. Its performance was as shown in Table 1. Comparative Example 4 Comparative Example 2 except for using the polyester of Production Example 4 and hexadecylmethylamine as the amine.
In the same manner as above, a non-capsule magnetic toner containing only core particles was obtained. Although this product had good developability and fixability, it was not practical due to blocking when left unused. Reference Example 1 Core material particles were prepared in the same manner as in Example 1 except that hardened beef tallow alkylpropylene diamine was not used. The viscosity of the kneaded product did not substantially increase during heating and kneading of the core material. Further, a coating layer was provided around the core material particles in the same manner as in Example 1 to prepare a capsule toner. Example 1 Using the prepared capsule toner
A copying test was carried out in the same manner as in Example 1, and a heat fixation test was also carried out in the same manner as in Example 1. The heat fixation start temperature was the same as that of the capsule toner of Example 1, but the high temperature offset temperature was The temperature was about 15° C. lower than that of the capsule toner of Example 1. Reference Example 2 Core material particles were prepared in the same manner as in Example 1, except that 0.1 part of hardened tallow alkylpropylene diamine was used. During heating and kneading of the core material, the viscosity of the kneaded material increased slightly. Furthermore, a coating layer was provided around the core material particles in the same manner as in Example 1 to prepare a capsule toner. Using the prepared capsule toner, a copying test was conducted in the same manner as in Example 1, and a heat fixability test was also conducted in the same manner as in Example 1. However, the high temperature offset temperature was about 14° C. lower than that of the capsule toner of Example 1. Reference Example 3 Core material particles were prepared in the same manner as in Example 1, except for using 30 parts of hardened tallow alkylpropylene diamine. During heating and kneading of the core material, the viscosity of the kneaded material increased significantly. Furthermore, a coating layer was provided around the core material particles in the same manner as in Example 1 to prepare a capsule toner. Using the prepared capsule toner, a copying test was conducted in the same manner as in Example 1, and a heat fixability test was also conducted in the same manner as in Example 1.
The temperature increased by 10° C. or more, and the heat fixability of the capsule toner of Reference Example 3 was decreased. Example 5 100 parts of polyester (Production Example 2), 1 part of hardened beef tallow alkylpropylene diamine, 70 parts of magnetic powder (Magnetite EPT-1000 manufactured by Toda Industries), low molecular weight polypropylene (viscol manufactured by Sanyo Chemical Industries)
A mixture consisting of 5 parts of 660P) was heated and kneaded with a roll. After allowing this to cool, it was crushed to a size of 1 to 2 mm, and further finely pulverized using a jet mill and classified using an air classifier to obtain core material particles with an average size of about 12 μm. Separately, a styrene/butyl methacrylate/ethyl acrylate/2-ethylhexyl acrylate/itaconic acid copolymer emulsion (2 mol% itaconic acid, 42% solid content) was prepared. The glass transition temperature of the constituent resin of this emulsion is 65℃, and the softening point is 135.
℃, Mw 280,000, and Mw/Mn 8.5. Further, an acrylic copolymer resin (Seiko Kagaku, Hylos X-316, Oxidation 60) was dissolved in ammonia alkaline water to make a 25% aqueous solution. 8 parts of the above resin aqueous solution are mixed with 20 parts of the above emulsion, and 50 parts of the above core material particles and water are mixed.
After adding 200 parts and thoroughly mixing and dispersing, spray drying was performed using a spray dryer at an inlet temperature of 160°C and an outlet temperature of 80°C to coat the emulsion-constituting copolymer and alkali-soluble resin around the core material particles. A resin coating layer was provided as the main body. Colloidal silica (Aerosil R-972) was added to the capsule toner thus obtained, and a copying test was conducted in the same manner as in Example 1. The results were as shown in Table 1. Example 6 A capsule toner was obtained in the same manner as in Example 5 except that the polyester of Production Example 2 was used and hexadecyldimethylamine was used as the amine. Its performance was as shown in Table 1. 【table】

Claims (1)

[Scope of Claims] 1. A developer for developing an electrostatic image used for heat fixing, containing a capsule toner in which the surface of the core particle of a heat fixable material containing a binder resin and a colorant as main components is coated with a thermoplastic resin. In the agent, the binder resin contains 60
Glass transition temperature below ℃, softening point between 50-110℃,
The thermoplastic resin contains an amorphous polyester having an acid value of 10 to 150 and an aliphatic amine or a derivative thereof in an amount of 1/500 to 1/5 of the weight of the polyester, and the thermoplastic resin has an organic acid monomer content of 0.2 to 10 mol%. and two or more monomers selected from the group consisting of styrene or its derivatives, acrylic esters, methacrylic esters, and maleic esters, and is
Glass transition temperature over 100~150℃, softening point 15
A developer for electrostatic image development, characterized in that it is a vinyl copolymer resin having Mw of 10,000 or more and Mw/Mn of 5 or more.