JPH04281462A - Capsule toner - Google Patents

Abstract

PURPOSE:To provide the microcapsule toner which has excellent fixability and can be fixed with a small-sized fixing device without deteriorating the properties of an org. photosensitive body. CONSTITUTION:The core material of the electrophotographic capsule toner consisting of a core material and a shell material coating this core material contains at least coloring materials, drying oil and polymer and this polymer dissolves or swells in the drying oil.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer used in an electrophotographic apparatus, and more particularly to a capsule toner developer suitable for a device that uses pressure as a fixing method.

0002

[Prior Art] Various capsule toners consisting of a core material and a shell material have been proposed. For example, in Japanese Patent Application Laid-open No. 132838/1983, a soft solid is used as a core material in an organic solvent. Dissolved or dispersed capsule toners are described, and JP-A-58-145964 and JP-A-60-83958 disclose capsule toners in which the core material contains at least a high boiling point solvent and a polymer. Further, Japanese Patent Application Laid-Open No. 163373/1983 discloses an invention in which a specific chlorinated paraffin is used as a high boiling point solvent in the core material.

0003

[Problems to be Solved by the Invention] However, the capsule toners proposed in the past have not yet been fully satisfactory. For example, in the cases described in JP-A-58-145964 and JP-A-60-83958, the high boiling point solvent used is a so-called plasticizer, which has a large dissolving power for resin, and therefore is suitable for use as a photoreceptor. It has been found that when an organic photoreceptor is used, the photoreceptor is deteriorated due to damage to the capsule, high-boiling solvent that oozes out of the thin-shelled capsule, or evaporates. Furthermore, in the case described in JP-A No. 63-163373, chlorinated paraffin used as a high-boiling solvent essentially has a dissolving power for general-purpose resins such as acrylic resin, polycarbonate resin, and polyester resin. Therefore, there is a problem that the organic photoreceptor is altered in quality. As an alternative to this, it is known to use a saturated aliphatic hydrocarbon solvent as the solvent, but for example, in the case described in JP-A-51-132828, the polymer used is a long acrylic acid. Chain alkyl ester polymers or petroleum resins are used, which have a relatively low Tg and are brittle, so the fixed image has problems such as the image easily smearing due to finger rubbing, etc., making the characters illegible. . Therefore, in order to firmly fix the paper by pressure fixing, it is necessary to apply strong pressure (e.g. 200 to 300 kg).
/cm2). Therefore, there is a problem that the fixing device becomes large and heavy. The present invention aims to solve the above-mentioned problems with conventional capsule toners. That is, an object of the present invention is to provide a microcapsule toner that does not alter the quality of an organic photoreceptor, has excellent fixing properties, and can be fixed using a small fixing device.

0004

[Means for Solving the Problems] The present invention provides an electrophotographic capsule toner comprising a core material and a shell material covering the core material, wherein the core material contains at least a colorant, a drying oil, and a polymer. , the polymer is characterized in that it dissolves or swells in drying oil.

The present invention will be explained in detail below. In the capsule toner of the present invention, the core substance is composed of at least a colorant, a drying oil, and a polymer. Examples of drying oils include linseed oil and boiled oil. These are composed of glycerides such as linolenic acid, linoleic acid, and oleic acid, but any glycerides of carboxylic acids having unsaturated bonds can be used. However, linseed oil is most preferred in terms of price, availability, etc.

Colorants include inorganic pigments such as carbon black, red iron, navy blue, and titanium oxide, azo pigments such as fast yellow, disazo yellow, pyrazolone red, chelate red, brilliant carmine, and para brown, copper phthalocyanine, and metal-free phthalocyanine. Examples include phthalocyanine pigments such as, flavanthrone yellow, dibromoanthrone orange, perylene red, quinacridone red, dioxazine violet, and other condensed polycyclic pigments. Further, disperse dyes, oil-soluble dyes, etc. can also be used. Furthermore, when used as a magnetic one-component toner, all or part of the black colorant can be replaced with magnetic powder. As the magnetic powder, magnetite, ferrite, or a metal carrier such as cobalt, iron, or nickel, or an alloy thereof can be used.

In the present invention, the polymer used for the core material must be soluble or swellable in the drying oil. This is because, if the polymer does not dissolve or swell in the drying oil, the polymer alone will exist on the transfer paper during fixing, resulting in significantly poor fixing. Examples of the polymer used in the present invention include polymer compounds represented by the following general formula.

(In the formula, R represents a hydrogen atom or a methyl group, and n is 7 to
(representing an integer of 17) generally has a weight average molecular weight of 10.0
00-300,000, preferably 10,000-10
A range of 0,000 can be used.

In the present invention, it is preferable to contain a petroleum resin or a rosin resin in addition to the above polymer. Particularly when the above polymer alone has fluidity, it is effective to use a petroleum resin or a rosin resin in combination, thereby improving the fixing speed and fixing strength. Petroleum resins include aliphatic resins, aromatic resins, copolymer resins, alicyclic hydrogenated petroleum resins, alkyl phenol resins, and coumaron indene resins. Among these, aromatic petroleum resins are particularly preferred in terms of compatibility with the polymer. Examples of the rosin resin include rosin, modified rosin, glycerin ester of the rosin, and pentaerythritol ester of the rosin.

In the capsule toner of the present invention, in addition to the above-mentioned polymers and resins, wax may also be contained as a component of the core material for the purpose of preventing offset. Examples of the wax include natural waxes such as paraffin wax, microcrystalline wax, montan wax, carnauba wax, candelilla wax, and beeswax, and synthetic waxes such as polyethylene wax, modified wax, cetyl alcohol, and stearic acid.

On the other hand, the outer shell is composed of a resin component, and any resin component known for encapsulation can be used. For example, polyurea resins, polyurethane resins, polyamide resins, polyester resins, epoxy resins, epoxyurea resins, and epoxyurethane resins are preferred, and among these, polyurea resins or polyurethane resins alone, or a mixture of both, or epoxyurea resins or It is more preferable to use an epoxy urethane resin alone or a mixture of both. Further, the surface of the outer shell may be grafted, for example, by graft polymerization with a vinyl monomer such as an acrylic ester or a methacrylic ester. The thickness of the outer shell is desirably different depending on whether it is intended for pressure fixing or heat fixing, and the types or composition ratios of the constituent components may also be varied.

When producing the capsule toner of the present invention,
There are no particular restrictions on the encapsulation method, and any known method can be used; however, considering the completeness of the coating and the mechanical strength of the outer shell, an encapsulation method using interfacial polymerization is superior. . Capsules can be manufactured by interfacial polymerization using known methods (for example, Japanese Patent Application Laid-open Nos. 179860/1986, 66948/1983, and 59/1982).
-148066 and 59-162562)
. When manufacturing capsules for pressure fixing,
As the core material, a core material mainly consisting of a component having pressure fixing properties is used, and when heat fixing is intended, a core material mainly containing a component having heat fixing properties is used.

[0013] The above polymer is used as one component in the core material,
The method for incorporating it into the capsule is to prepare it in advance in the form of a polymer together with other core material components, a low boiling point solvent, and an outer shell forming component, and to form the outer shell through interfacial polymerization, or at the same time, or after the outer shell has been formed. There are two methods: one is to expel the low-boiling point solvent out of the system to form a core material, and the other is to charge it as a monomer, form an outer shell through interfacial polymerization, and then polymerize the monomer to form a core material. Either may be used.

External additives may be added to the capsule toner of the present invention. External additives include long chain fatty acids and esters such as stearic acid, amides, metal salts, molybdenum dioxide, boron nitride,
Examples include fine powders of silica, aluminum oxide, titanium dioxide, zinc oxide, etc., fine powders of fluororesins, polycyclic aromatic compounds, waxy substances, crosslinked or non-crosslinked fat fine powders, etc., and usually have a low surface. solid particles with energy or a smooth surface with a low coefficient of friction, or non-adhesive;
Fine particles having some abrasive properties are preferably used.

[0015]

[Examples] The present invention will be explained below with reference to Examples. Example 1 (Preparation of capsule particles) Polylauryl methacrylate (
Mw = 5 x 104) 50g and petroleum resin (FTR
6125: manufactured by Mitsui Oil Chemicals Co., Ltd.) 15g, linseed oil 25g
and 30 g of ethyl acetate. Magnetic powder (EPT-1000: manufactured by Toda Kogyo Co., Ltd.) 55
g was added and subjected to dispersion treatment in a ball mill for 20 hours. Next, 15 g of isocyanate (Sumidur L, manufactured by Sumitomo Bayer Urethane) and 15 g of ethyl acetate were added to 100 g of this dispersion and thoroughly mixed (this liquid is referred to as liquid A). On the other hand, 10 g of hydroxypropyl methylcellulose (Metrose 65H50, manufactured by Shin-Etsu Chemical Co., Ltd.) was dissolved in 200 g of ion-exchanged water and cooled to 5° C. (this solution is referred to as Solution B).

Solution B was stirred using an emulsifier (auto homo mixer: manufactured by Tokushu Kika Kogyo Co., Ltd.), and solution A was slowly added thereto for emulsification. In this way, an O/W emulsion in which the average particle size of oil droplets in the emulsion was about 12 μm was obtained. Next, in place of the emulsifier, a stirrer equipped with propeller-type stirring blades (Three-One Motor: manufactured by Shinto Kagakusha) was used.
Stirred at 00 revolutions/min. After 10 minutes, 100 g of a 5% diethylenetriamine aqueous solution was added dropwise thereto. After dropping, heat to 60°C and add 3 ml of ethyl acetate while degassing the ethyl acetate.
A time encapsulation reaction was performed. After the reaction was completed, the mixture was poured into 2 liters of ion-exchanged water, thoroughly stirred, and allowed to stand still. After the capsule particles had settled, the supernatant was removed. This operation was repeated seven more times to wash the capsule particles. In this way, capsule particles of the present invention were obtained. Ion-exchanged water was added to the capsule particles to prepare a suspension with a solid content concentration of 40%.

125 g of the prepared capsule particle suspension (
(equivalent to 50g of capsule particles), 125g of ion exchange water
was added and stirred at 200 rpm using a stirrer equipped with a propeller-type stirring blade (Three-One Motor: manufactured by Shinto Kagakusha). After adding 5 g of IN nitric acid and 4 g of 100% cerium sulfate aqueous solution to this, 0.5 g of ethylene glycol dimethacrylate was added, and the reaction was carried out at 15° C. for 3 hours. After the reaction was completed, the mixture was poured into 1 liter of ion-exchanged water, thoroughly stirred, and allowed to stand still. After the capsule particles had settled, the supernatant was removed. This operation was repeated two more times to wash the capsule particles. In this way, capsule particles in which ethylene glycol dimethacrylate was graft-polymerized on the surface of the capsule shell were obtained. Resuspend this in ion-exchanged water again,
Stirring was carried out at 200 revolutions/min using a stirrer equipped with a propeller-type stirring blade (Three-One Motor: manufactured by Shinto Kagakusha Co., Ltd.). Next, 0.4 g of potassium persulfate, 1 g of trifluoroethyl methacrylate, and 0.16 g of sodium bisulfite were sequentially added to the mixture, and the reaction was carried out at 25° C. for 3 hours. After the reaction was completed, the mixture was poured into 2 liters of ion-exchanged water, thoroughly stirred, and allowed to stand still. After the capsule particles had settled, the supernatant was removed. This operation was repeated four more times to wash the capsule particles. In this way, a capsule toner in which trifluoroethyl methacrylate was graft-polymerized on the surface of the capsule shell was obtained. The obtained capsule suspension was poured into a stainless steel vat and dried in a dryer (manufactured by Yamato Kagaku Co., Ltd.) for 6 hours.
It was dried at 0°C for 10 hours. Next, this capsule toner 1
To 00 parts, 0.7 parts of hydrophobic silica (R972: manufactured by Nippon Aerosil Co., Ltd.) was added, and after thorough mixing, capsule toner A was obtained.

As a comparative example, capsule toner B was obtained by performing encapsulation in the same manner as above using dioctyl adipate instead of linseed oil. These capsule toners were manufactured using a Fuji Xerox 4105 printer modified for capsule toner (developing unit, fixing unit (pressure 1
00kg/cm2))), and a print test was performed. The results are shown in Table 1.

[0019]

[Table 1]

As is clear from the above results, the capsule toner of the present invention eliminates the deterioration of the organophotoreceptor, which has been a problem in the past, and stably fixes due to the hardening of linseed oil, so it is easy to use when rubbed with fingers, etc. It can be seen from the test that a product exhibiting good fixing properties without image smearing can be obtained.

Example 2 Except for using boiled oil in place of linseed oil in Example 1,
Capsule toner C was produced in the same manner as in Example 1 (capsule toner C). This capsule toner C was prepared in Example 1.
As a result of testing with a modified Fuji Xerox 4105 printer used in , clear printed images and stable fixed images were obtained. Further, as a result of repeated printing tests, even after 50,000 prints, the performance remained unchanged and the organic photoreceptor did not crack.

Example 3 Capsule toner A was prepared in Examples 1 and 2 by using the modified Fuji Xerox 4105 printer fixing device used in Example 1 and setting the pressure at 50 kg/cm 2 and the temperature at 60° C. B and C were tested. As a result, in the case of Capsule Toners A and C, the image did not run in the finger rubbing test immediately after fixing, and showed stable fixing performance, but in the case of Capsule Toner B, the image slightly remained fixed regardless of the standing time. flowed.

[0023]

Effects of the Invention In the capsule toner of the present invention, since the core substance contains a drying oil and a polymer that dissolves or swells in the drying oil, the core substance flows out onto the transfer paper due to pressure during fixing. After soaking, the drying oil contained in the core material hardens,
It becomes possible to impart sufficient strength to the fixed image and improve fixing performance. Furthermore, since the drying oil does not alter the quality of the organic photoreceptor, even when the capsule toner of the present invention is cleaned using a blade cleaner, for example, some of the capsule toner is destroyed, but some of the capsule toner oozes out. Depending on the vapor of the drying oil, the organophotoreceptor may be altered (
(for example, cracks, etc.).

Claims (2)

[Claims] Claim 1: A capsule toner comprising a core material and a shell material covering the core material, wherein the core material contains at least a colorant, a drying oil, and a polymer, and the polymer is dissolved or swollen in the drying oil. A capsule toner for electrophotography, which is characterized by: 2. The capsule toner according to claim 1, wherein the drying oil is linseed oil.