JPS63128359A - Capsule toner for heat roller fixing - Google Patents

Abstract

PURPOSE:To obtain excellent low-temp. fixability and offset resistance and to expand a practicable fixable temp. range by incorporating nonlinear polyester having a long chain aliphat. hydrocarbon unit at the main chain and/or side chain and wax into the titled toner. CONSTITUTION:This capsule toner has meltable core material particles and the shells consisting of a thermoplastic resin so provided as to coat the surface of the core material particles. The nonlinear polyester which is the nonlinear polyester obtd. by condensation polymn. of monomer components contg. a dihydric alcohol monomer and divalent carboxylic acid monomer and trihydric or higher alcohol monomer and/or trivalent or higher carboxylic acid monomer and has the long chain aliphat. hydrocarbon unit at the main chain and/or side chain thereof and the wax are incorporated into the meltable core material particles. The viscoelasticity of the toner when melted is, therefore, adjusted to an adequate size by the nonliearization, by which the transfer of the toner material to a heat roller of a heat roller fixing device is hardly generated and the excellent offset resistance is obtd.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a capsule toner used for developing electrostatic latent images formed in electrophotography, electrostatic printing, electrostatic recording, etc. This invention relates to a capsule toner for heat roller fixing.

[Background of the invention]

For example, in electrophotography, an electrostatic latent image is usually formed on an electrostatic latent image carrier made of a photoconductive photoreceptor by charging and exposure, and then this electrostatic latent image is transferred using toner, which is a colored particle. After development, the resulting toner image is transferred to an image support such as transfer paper, and then fixed by heat or pressure to form a visible image.

Conventional methods for fixing toner images include a method in which the toner is heated and melted in a non-contact state using a heater;
Some of the known methods include fixing by dissolving the toner with an organic solvent, fixing by pressurizing the toner, and so-called hot roller fixing method in which a heated roller is brought into direct contact with the toner to melt and press the toner to fix it. The hot roller fixing method is widely used because it has high thermal efficiency and enables high-speed fixing.

However, in recent years, efforts have been made to (a) suppress deterioration caused by overheating of copying machines, and (b) shorten the warm-up time required for the heat roller to rise to a temperature capable of fixing after the heat roller fixing device is activated. (c) To reduce the temperature drop of the heat roller due to the absorption of heat by an image support such as transfer paper, and to enable stable image formation over a number of consecutive times; and (d) copying. From the viewpoint of downsizing machines and improving safety, there is a strong demand to reduce the power consumption of the heater built into the fuser and to enable the fusing process while keeping the heat roller temperature lower. There is.

Therefore, toners are required to (1) be able to achieve good fixing at even lower temperatures, that is, have excellent low-temperature fixing properties, and basically meet the following conditions: is necessary.

(2) In the heat roller fixing method, which is preferred as a fixing method, there is an offset phenomenon, that is, a part of the toner that makes up the image is transferred to the surface of the heat roller during fixing, and this is transferred again to the transfer paper that is sent next. Since the phenomenon of smearing an image is likely to occur, toner should be provided with performance that prevents transfer to a hot roller, that is, offset resistance.

(3) It should be able to exist stably as a powder without agglomerating under the environmental conditions of use or storage, that is, it should have excellent blocking resistance.

(4) It has good triboelectric charging properties, and the development process, transfer process, and cleaning process can be carried out well, and a clear image without capri can be obtained.

(5) The so-called filming phenomenon in which toner substances adhere to the surface of a photoreceptor or carrier particles is suppressed, and images can be stably formed many times.

Conventionally, by using a capsule toner as a toner, the capsule toner is composed of core particles and an outer shell provided to cover the surface of the core particles.
Techniques for improving low-temperature fixability have been proposed. This type of capsule toner uses a low melting point compound or a material with a low glass transition point as core material particles in order to improve meltability at low temperatures. Specifically, the following techniques are disclosed.

■Technology in which core material particles are composed of wax
(Refer to Publication No.-1588).

(2) A technique in which the core particles are made of polyester crosslinked with a polyvalent metal compound (see Japanese Patent Laid-Open No. 174957/1983).

■Technology in which core material particles are composed of low-melting point polyester (
(See Japanese Unexamined Patent Publication No. 176642/1983).

■Technology in which the core material particles are made of a low molecular weight styrene-acrylic resin with a gel content of 20 to 70% (see JP-A-58-176643)
.

■Technology in which the core particles are made of amorphous polyester with a glass transition point of 60°C or lower (Japanese Patent Application Laid-Open No. 58-205161
(see publication).

(2) A technique in which the core material particles are composed of a crosslinked vinyl polymer having a glass transition point of 55°C or less and a gel content of 20% or more (see Japanese Patent Laid-Open No. 58-205161).

■The core material particles have a glass transition point of 60℃ or less and an acid value of 1.
Technology composed of amorphous polyester of 0 to 150 (
(See Japanese Patent Application Laid-Open No. 58-205163).

■Technology in which the core material particles are composed of amorphous polyester and a polyvalent metal compound (Japanese Unexamined Patent Publication No. 58-2051
(See Publication No. 64).

[Problem that the invention seeks to solve]

However, in the above technique (2), when a hot roller fixing method is applied as the fixing method, the offset resistance is considerably poor and the practicality is extremely low.

In addition, although it is recognized that the above technologies (1) to (2) have improved performance under the environmental conditions of normal temperature and normal pressure (e.g., temperature 20°C, relative humidity 60%), compared to the above technology (2), they still have no offset resistance. However, there is a problem in that the temperature range in which fixing can be performed without causing the occurrence of an offset phenomenon is narrow, and the practicality of the fixing method is still low.

Moreover, low temperature and low humidity (e.g. temperature 10℃, relative humidity 40%)
), the temperature of the image support such as transfer paper is low, so the toner tends to be insufficiently melted during fixing, resulting in poorly fixed toner adhering to the rollers that make up the fixing device. There is a problem in that the accumulation contaminates the roller, which causes conveyance failures such as paper jams, and shortens the useful life of the roller.

As described above, the reality is that, depending on the conventional capsule toner, a fully satisfactory capsule toner for heat roller fixation has not yet been obtained.

This is because conventional capsule toners are basically intended to be applied to pressure fixing methods. That is, the toner is designed to be suitable for the fixing method to which the toner is applied. For example, when a toner designed to be applied to the pressure fixing method is applied to the heat roller fixing method, problems such as offset phenomenon may occur. occurs, and it is not necessarily possible to form a sufficient copy image.

[Purpose of the invention]

The present invention has been made based on the above-mentioned circumstances, and an object thereof is to have excellent low-temperature fixing properties and offset resistance, and to have a wide practical fixing temperature range, and to have a low-temperature, low-humidity environmental condition. It maintains its excellent low-temperature fixing properties even under low temperatures, and it is possible to fix without staining the rollers that make up the fixing device.It also has excellent blocking resistance, frictional charging properties, and filming resistance. It is an object of the present invention to provide a capsule toner for hot roller fixing that can stably form fog-free and clear images many times.

[Means for solving problems]

The capsule toner for heat roller fixing of the present invention includes meltable core particles and an outer shell made of a thermoplastic resin provided to cover the surface of the core particles. The meltable core material particles contain a divalent alcohol monomer, a divalent carboxylic acid monomer, a trivalent or higher polyhydric alcohol monomer, and/or a trivalent or higher polyvalent carboxylic acid monomer. A non-linear polyester obtained by condensation polymerization of monomer components containing a non-linear polyester having a long-chain aliphatic hydrocarbon unit in its main chain and/or side chain, and a wax. It is characterized by becoming.

[Function and effect of the invention]

According to the capsule toner for hot roller fixing of the present invention, the resin contained in the core particles contains a divalent alcohol monomer, a divalent carboxylic acid monomer, and a polyhydric alcohol monomer having a valence of 3 or more. Since it is a non-linear polyester obtained by condensation polymerization of a monomer component containing a polycarboxylic acid monomer and/or a polycarboxylic acid monomer having a valence of 3 or more, the viscoelasticity of the toner when melted is moderate due to non-linearity. This size makes it difficult for the toner substance to transfer to the heat roller of the heat roller fixing device, resulting in excellent anti-offset properties, and the non-linearity makes the toner hard, improving the durability of the toner. Moreover, since the nonlinear polyester has long chain aliphatic hydrocarbon units in its main chain and/or side chain, the toner can be melted at a lower temperature due to the characteristics of the long chain aliphatic hydrocarbon units. In addition, the adhesion to image supports such as transfer paper is improved, and since the core material particles contain wax, this wax's property of melting efficiently at low temperatures is added. The low-temperature fixability of the toner becomes even better, and particularly excellent low-temperature fixability is exhibited under environmental conditions of low temperature and low humidity. In this way, toner can be fixed at a lower temperature without causing the offset phenomenon, so the fixable temperature range is sufficiently widened.
It is possible to obtain a toner which is excellent in practical use.

Since wax has the property of being hard at temperatures below its melting point, it greatly contributes to the hardening of the core material particles.
The toner has excellent durability, and since wax has excellent releasability in its molten state, the transfer of toner material to the heat roller is more reliably suppressed, and as a result, the heat of the heat roller fuser is suppressed. There is little dirt on the roller, and images can be formed successfully many times.

Since the core particles are covered with an outer shell made of thermoplastic resin, the outer shell provides excellent blocking resistance, good triboelectric charging properties, cleaning properties, and excellent anti-filming properties. .

[Specific structure of the invention]

Hereinafter, a specific configuration of the present invention will be explained.

In the present invention, basically, a divalent alcohol monomer and a divalent carboxylic acid monomer, and a trivalent or higher polyhydric alcohol monomer and/or a trivalent or higher polyvalent carboxylic acid monomer are used. A non-linear polyester obtained by condensation polymerization of monomer components including a non-linear polyester having long-chain aliphatic hydrocarbon units in its main chain and/or side chain (hereinafter referred to as "specific A capsule toner for heat roller fixation is constructed by covering the surface of core material particles containing polyester (also referred to as "polyester") and wax with an outer shell made of a thermoplastic resin.

In the present invention, the specific polyester constituting the core particles preferably has a glass transition point Tg of 40 to 70°C, particularly preferably 40 to 60°C. By selecting a material having a glass transition point Tg within such a range, even better low-temperature fixing properties, anti-offset properties, and durability can be obtained. That is, when the glass transition point Tg is too small, the core material particles become soft and the offset resistance and durability may be reduced, while when the glass transition point Tg is too large, the low-temperature fixing properties are reduced. Especially in low temperature and low humidity (e.g. temperature 10℃,
Sufficient low-temperature fixability may not be obtained under environmental conditions (relative humidity: 40%).

In the present invention, the glass transition point Tg refers to a baseline temperature below the glass transition point when measured using a differential scanning calorimeter [low temperature D'5CJ (manufactured by Rigaku Denki Co., Ltd.) at a heating rate of 10°C/111in]. The temperature at the intersection of the extension line and the tangent line showing the maximum slope from the rising part of the peak to the top of the peak.

In the present invention, the core material particles may contain other components in addition to the specific polyester and wax, and the specific polyester is contained in the core material particles in a proportion of at least 50% by weight or more. It is preferable that If this ratio is too small, the offset resistance and durability of the capsule toner may deteriorate.

In the present invention, monomer components used in the synthesis of the specific polyester constituting the core particles include the following (
Those shown in (a) to (c) can be mentioned, and other monomers may be used as necessary.

(a) Divalent alcohol monomers and divalent carboxylic acid monomers as components constituting the basic skeleton, that is, the main chain of polyester.

(b) Trivalent or higher polyhydric alcohol monomers and/or trivalent or higher polyvalent carboxylic acid monomers that participate in nonlinearization, that is, branching or network formation of polyester.

(c) Divalent or higher alcohol monomer having long chain aliphatic hydrocarbon units and/or long chain for introducing long chain aliphatic hydrocarbon units into the main chain and/or side chain of polyester A divalent or higher carboxylic acid monomer having an aliphatic hydrocarbon unit.

Incidentally, the long chain in the long chain aliphatic hydrocarbon unit refers to a straight chain having 3 or more carbon atoms, preferably 3 to 30 carbon atoms. Especially in terms of low temperature fixability, it is 5-2.
2 is preferred.

As the divalent alcohol monomer in (a) above,
Diols such as ethylene glycol, diethylene glycol, triethylene glycol, 1.2-7" propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butynediol; 1. Examples include 4-bis(hydroxymethyl)cyclohexane, bisphenol A1, hydrogenated bisphenol A1, etherified bisphenol, etc. Among these, etherified bisphenol is particularly preferred, and specific examples include, for example, polyoxypropylene (2,2 ) -2,2-bis(4-hydroxyphenyl)propane, polyoxyethylene (2)-2,
2-bis(4-hydroxyphenyl)propane, polyoxypropylene (6)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene (1,3)
-2,2-bis(4-hydroxyphenyl)propane and the like can be mentioned. The proportion of the divalent alcohol monomer used is preferably 10 to 90 mol% based on the total alcohol component.

As the divalent carboxylic acid monomer in (a) above,
For example, maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, malonic acid, anhydrides of these acids. , a dimer of lower alkyl ester and lyluic acid, and other divalent organic acid monomers. The proportion of the divalent carboxylic acid monomer used is preferably 10 to 90 mol%, particularly 20 to 6 mol%, based on the whole acid component.
0 mol% is preferred.

Examples of the trivalent or higher polyhydric alcohol monomer in (b) above include sorbitol, L2,3.6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, and sucrose. , 1,2,4-butanetriol, L2,5
-Pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3.5-trihydroxymethylbenzene, and the like. The proportion of the trivalent or higher polyhydric alcohol monomer used is preferably 5 to 50 mol%, particularly preferably 10 to 40 mol%, based on the entire alcohol component.

Examples of the trivalent or higher polycarboxylic acid monomer in (b) above include 1,2,4-benzenetricarboxylic acid,
1.2.5-benzenetricarboxylic acid, ■.

2,4-cyclohexanetricarboxylic acid, 2,5.7-
Naphthalenetricarboxylic acid, L2.4-naphthalenetricarboxylic acid, L2,4-butanetricarboxylic acid, 1.2
．． 5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxylpropane,
Tetra(methylenecarboxyl)methane, 1.2,7.
8-octane tetracarboxylic acid, empol trimer acid,
Examples include anhydrides of these acids. The proportion of the polycarboxylic acid monomer having a valence of 3 or more is preferably 1 to 30 mol % based on the entire acid component.

2 having a long chain aliphatic hydrocarbon unit in the above (c)
Among the alcohol monomers having a long chain aliphatic hydrocarbon unit in the main chain of the alcohol monomer, examples include propylene glycol, 1,4-butanediol, and 1,6-hexanediol. etc. can be mentioned. Furthermore, among the carboxylic acid monomers having a long chain aliphatic hydrocarbon unit in the above (c), those having a long chain aliphatic hydrocarbon unit in the main chain of the carboxylic acid monomer are , for example, glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid, sebacic acid and the like. Dihydric or higher alcohol monomers having long chain aliphatic hydrocarbon units in the main chain or
The carboxylic acid monomer having a value higher than or equal to that of the non-linear polyester has a long-chain aliphatic hydrocarbon unit present in the main chain of the non-linear polyester in an amount of 1 to 60 mol%, preferably 5 to 50 mol% of the constituent units of the main chain. It is preferable to use the proportions such that

2 having a long chain aliphatic hydrocarbon unit in the above (c)
Among alcohol monomers having a valence of 2 or more, those having a long-chain aliphatic hydrocarbon unit in the side chain of the alcohol monomer include alcohol monomers with a valence of 2 or more whose side chain is a long-chain aliphatic hydrocarbon unit. Examples include those substituted with groups.

As such divalent or higher alcohol monomers, those exemplified as alcohol monomers in (a) and (b) above can be used. Furthermore, among the carboxylic acid monomers having a long chain aliphatic hydrocarbon unit in the above (c), those having a long chain aliphatic hydrocarbon unit in the side chain of the carboxylic acid monomer are , carboxylic acid monomers having divalent or higher valences whose side chains are substituted with long-chain aliphatic hydrocarbon groups. As such divalent or higher carboxylic acid monomers, those exemplified as carboxylic acid monomers in (a) and (b) above can be used. Among these, particularly preferred are, for example, n-dodecenylsuccinic acid, iso-dodecenylsuccinic acid, n-dodecylsuccinic acid, iso-dodecylsuccinic acid, iso-octylsuccinic acid, n-octylsuccinic acid, and n-butylsuccinic acid. etc. can be mentioned. The proportion of divalent or higher alcohol monomers having long chain aliphatic hydrocarbon units in their side chains and/or divalent or higher carboxylic acid monomers having long chain aliphatic hydrocarbon units in their side chains should be The total amount is preferably 1 to 50 mol%, particularly preferably 10 to 30 mol%, based on the entire monomer component.

In the present invention, wax is contained as an essential component in the core material particles together with the specific polyester. Due to the presence of this wax, when the toner is fixed by the heat roller, the toner contacts the heat roller and melts quickly, and a thin film of wax is formed at the interface with the heat roller.
As a result, transfer and adhesion of toner material to the heat roller can be effectively prevented, and the service life of the heat roller can be further improved.

The wax is preferably one that melts sharply at its melting point Tmp and has a low melting point Tmp. In addition, in order to melt sharply and have a low viscosity, the melt viscosity at 120°C must be 5.0OOcp.
s or less, and the number average molecular weight Mn is preferably 10,000 or less.

The melting point Tmp of the wax is preferably 40 to 120°C, particularly preferably 50 to 110°C. When the melting point Tmp of the wax is too high, low-temperature fixing properties may deteriorate, while when the melting point Tmp is too low, anti-offset properties and durability may deteriorate.

Note that the melting point Tmp of wax is determined by differential scanning calorimetry (
DSC).

In other words, several mg of the sample was heated at a constant heating rate (10°C/w).
The melting peak value when heated at in) is defined as the melting point Tmp.

Examples of wax that can be used in the present invention include solid paraffin wax, microwax, rice wax, amide wax, fatty acid wax, fatty acid metal salt wax, fatty acid ester wax, partially saponified fatty acid ester wax, silicone varnish,
Examples include higher alcohols and carnauba wax.

The content ratio of wax in the core material particles is preferably 5 to 50% by weight, particularly preferably 5 to 45% by weight. If the wax content is too small, the low-temperature fixing properties may be reduced, while if the wax content is too large, the offset resistance may be reduced.

In the present invention, in addition to the above-mentioned specific polyester and wax, other resins may be mixed in the core material particles as necessary. Examples of such other resins include styrene-acrylic resins, polyester resins other than the above-mentioned specific polyesters, epoxy resins, polyurethane resins, and styrene-butadiene resins.

In the present invention, the surface of the core particle is covered with an outer shell made of a thermoplastic resin, and as such a thermoplastic resin, those conventionally used as resins for toners can be used. Specific examples include vinyl polymers, polyester resins, epoxy resins, and polyurethane resins. Among these, vinyl polymers and polyester resins are particularly preferred, and specific examples include styrene-n-butyl acrylate copolymer, styrene-methyl methacrylate-n-butyl methacrylate copolymer, and terephthalic acid-bisphenol A.
Examples include propylene oxide condensates.

The thermoplastic resin forming the outer shell has a glass transition point Tg
It is preferable that the temperature is 50°C or higher. Glass transition point Tg
When is too small, the blocking resistance of the capsule toner may deteriorate.

In addition, the thermoplastic resin forming the outer shell has a ratio Mw/Mn of the weight average molecular weight 1h to the number average molecular weight Mn of 7.
It is preferable that it is 0 or more. When the value of this ratio Mw/Mn is too small, the offset resistance of the capsule toner may deteriorate.

In addition, the values of weight average molecular weight and number average molecular weight Mn can be determined by various methods, and there are slight differences depending on the measurement method, but in the present invention, they are determined by the following measurement method. be.

That is, the weight average molecular weight h, number average molecular weight Mn, and peak molecular weight are measured by gel permutation chromatography (GPC) under the conditions described below. At a temperature of 40° C., a solvent (tetrahydrofuran) is flowed at a flow rate of 1.2 −/min, and a sample solution of 8 mg of tetrahydrofuran having a concentration of 0.4 gldl is injected to perform measurement. When measuring the molecular weight of a sample, select measurement conditions in which the molecular weight of the sample falls within a range where the logarithm of the molecular weight and the count number of the calibration curve prepared using several types of monodispersed polystyrene standard samples are linear. .

The reliability of the measurement results is based on the NB5706 polystyrene standard sample (weight average molecular weight M
w -28,8×10' + number average molecule 1Mn=13
．． 7XIO', Mw/Mn=2.11) ratio Mid
This is confirmed by checking that the value of /Mn is 2.11±0.10.

Moreover, any column may be used as the GPC column as long as it satisfies the above conditions. Specifically, for example, TSK-GEL, 0MH6 (manufactured by Toyo Soda Co., Ltd.), etc. can be used.

The capsule toner of the present invention may optionally contain a colorant,
So-called toner components such as a charge control agent and a fixing property improving aid may be added. These toner components may be contained in the core particles or in the outer shell.

Capsule toner also contains additives such as fluidity improvers, abrasives, and cleanability improvers, which are adhered to the outer shell or are held by being driven into the outer shell. Good too.

Examples of colorants include carbon black, nigrosine dye, aniline blue, calco oil blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green offsalate,
Mention may be made of lamp black, rose bengal, mixtures thereof, and others.

Examples of the charge control agent include metal complex dyes, nigrosine dyes, and ammonium salt compounds.

Examples of the fixing property improving aid include polyolefins such as polyethylene and polypropylene. Among these, the softening point Tsp according to the ring and ball method is 7
A polyolefin having a temperature of 0 to 150°C is preferable, and a polyolefin having a softening point Tsp of 120 to 150°C is more preferable.

Inorganic fine particles can be preferably used as the fluidity improver and abrasive. The primary particle diameter of the inorganic fine particles is preferably 5 mμ to 2 μm, particularly 5 mμ to 5 mμ to 2 μm.
Preferably, it is 500*p.

In addition, the specific surface area according to the BET method is 20 to 500 m2/
It is preferable that it is g. The proportion of the inorganic fine particles used is preferably 0.01 to 5% by weight, particularly preferably 0.01 to 2.0% by weight of the capsule toner. Specific examples of inorganic fine particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, and oxide. Examples include chromium, cerium oxide, red iron oxide, antimony dioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.

Particularly preferred is fine silica powder.

The silica fine powder is a fine powder having a 5t-0-3t bond, and may be manufactured by either a dry method or a wet method. In addition to anhydrous silicon dioxide, aluminum silicate, sodium silicate, potassium silicate, magnesium silicate, zinc silicate, etc. may be used, but those containing 5iO7 in an amount of 85% by weight or more are preferable. As specific examples of fine silica powder, there are various commercially available products, but those having a hydrophobic group on the surface of the fine particles are particularly preferred.For example, "Aerosil R-972J,""AerosilR-974,""Aerosil R- 805J, “Aerosil R, -812J (manufactured by Aerosil Co., Ltd.), [
Taranox 500J (manufactured by Talco) and the like can be preferably used. In addition to these, fine silica powder whose surface has been treated with a silane coupling agent, a titanium coupling agent, silicone oil, a silicone oil having an amine in its side chain, etc. can be used.

Examples of the cleaning performance improver include fatty acid metal salts such as zinc stearate, calcium stearate, and stearic acid, and polymer particles such as methyl methacrylate particles and styrene particles.

Further, in the case of producing a magnetic toner, fine particles of magnetic material may be contained in one or both of the core material particles and the outer shell.

Such magnetic materials include ferrite, magnetite, iron, nickel, cobalt, and other ferromagnetic metals or alloys, compounds containing these elements, and compounds that do not contain ferromagnetic elements but can be treated with appropriate heat treatment. Mention may be made of alloys which become ferromagnetic, such as alloys of the type called Heusler alloys containing manganese and copper, such as manganese-copper-aluminum, manganese-copper-tin, chromium dioxide, and the like. The magnetic material is preferably contained in a uniformly dispersed form of fine powder with an average particle size of 0.1 to 1 p. And the content ratio of magnetic material is
The amount is preferably 10 to 70 parts by weight, particularly preferably 20 to 50 parts by weight, based on 100 parts by weight of the capsule toner.

In the present invention, core material particles can be manufactured, for example, by the following method.

(1) The specific polyester and wax for forming the core material particles, other resins added as necessary, and toner components such as colorants used as necessary, for example. A method of melting and kneading with an extruder, cooling, pulverizing with a jet mill, etc., and classifying this to obtain core material particles of the desired particle size.

(2) For example, the specific polyester and wax for forming the core material particles, other resins added as necessary, and toner components such as colorants used as necessary, are A method of obtaining core material particles of a desired particle size by melting and kneading using a ruder and then spraying the molten state using a spray dryer or the like.

(3) For example, the specific polyester and wax for forming the core material particles, other resins added as necessary, and toner components such as colorants used as necessary, are A method of obtaining core material particles of a desired particle size by melt-kneading using a ruder and dispersing the molten state in a liquid.

In addition, in the present invention, as a method for providing an outer shell on the surface of the core particle, a coating solution in which a thermoplastic resin for forming the outer shell is dissolved or dispersed in a solvent is applied, for example, by a dipping method.
By methods such as spray drying method and fluidized bed method,
A method can be used in which the coating layer is formed by coating the surface of the core material particles, heating and drying to volatilize the solvent, and curing the coating layer during or after drying. For example, when forming a coating layer by a fluidized bed method, the core particles are raised to an equilibrium height by a rising pressurized gas flow in a fluidized bed device, and then the core particles fall again. The coating solution can be applied by spraying and this spraying can be repeated to form the shell.

The capsule toner of the present invention may be combined with a carrier to form a two-component developer, or may be used as a magnetic capsule toner containing a magnetic substance to form a one-component developer consisting only of the magnetic capsule toner. It may be something that does.

The capsule toner of the present invention is a capsule toner for heat roller fixation, and is used to form an image, for example, in the following manner. That is, in electrophotography, an electrostatic latent image formed on a photoreceptor, which is a latent image carrier, is developed with a two-component developer or a one-component developer configured using the capsule toner of the present invention, The obtained toner image is electrostatically transferred, for example, to a support made of paper or the like, and then the transferred toner is fixed by a hot roller fixing method, thereby forming a fixed image.

A heat roller fixing device used in a heat roller fixing method is usually composed of a heat roller, a pressure roller disposed in opposition to the heat roller, and a heat source.

Further, a cleaning roller is disposed opposite to the heat roller as necessary. While maintaining the temperature of the heat roller within a certain range using a heating source, the toner is brought into direct contact with the heat roller by passing the toner-transferred support between the heat roller and the pressure roller. is heat-fixed to the support.

Further, the material of the heat roller is preferably a fluorine-based material or a silicone-based material, and the durability of the heat roller can be significantly improved due to the synergistic effect with the capsule toner according to the present invention.

[Specific examples]

Hereinafter, specific examples of the present invention will be described, but the present invention is not limited to these examples.

Production of resin A> (for the present invention) 162 parts by weight of sebacic acid, 19 parts by weight of trimellitic anhydride, and 344 parts by weight of polyoxypropylene (2,2)-2,2-bis(4-hydroxyphenyl)propane. part and diisopropyl orthotitanate (esterification catalyst) 0
．． 5 parts by weight in a flask and heated to a temperature of 160 to 180.
The reaction was carried out at .degree. C. under an inert atmosphere, and the water produced was distilled off. When no water was produced, the temperature was raised to 200° C., and the reaction was further carried out under reduced pressure to obtain a nonlinear polyester having a long chain aliphatic hydrocarbon unit in the main chain. This will be referred to as "Resin A". Note that the glass transition point 'rg of this resin A is 51°C.

<Production of resin B> (for the present invention) 46 parts by weight of fumaric acid, 105 parts by weight of n-dodecenylsuccinic anhydride, 38 parts by weight of trimellitic anhydride, polyoxypropylene (2,2) -2,2 -Bis(4-
344 parts by weight of (hydroxyphenyl)propane and 0.5 parts by weight of diisopropyl orthotitanate (esterification catalyst) are placed in a flask and reacted in the same manner as in the production of resin A, thereby carbonizing the side chains with long-chain aliphatics. A non-linear polyester having hydrogen units was obtained. This will be referred to as "Resin B". Note that the glass transition point Tg of this resin B is 48°C.

<Production of resin a> (for comparison) Polyoxypropylene (2,2)-2,2-bis(4-
482 g of hydroxyphenyl) propane, 190 g of polyoxyethylene (2)-2,2-bis(4-hydroxyphenyl) propane, and 120 g of terephthal fi.
Diisopropyl orthotitanate (esterification catalyst) 0.
8 g of the resin were placed in a flask and reacted in the same manner as in the production of Resin A to obtain a comparative non-linear polyester having no long-chain aliphatic hydrocarbon units. This is called "resin a"
”. In addition, the glass transition point Tg of this resin a is 65
It is ℃.

<Example 1> (1) Production of core material particles 100 parts by weight of the above resin A, 10 parts by weight of carbon black [Mogul Lj (manufactured by Cabot), and paraffin wax "Sasol Wax H1" (melting point Tm
p: 10B℃, manufactured by Sasol Corporation) in a V-type blender, melt-kneaded with two rolls, cooled, coarsely crushed with a hammer mill, and further finely crushed with a jet mill. It was classified using an air classifier to obtain core particles having a particle size of 1 to 30 nm. This is referred to as "core material particle 1."

(2) Production of outer shell Styrene-methyl methacrylate-acrylic acid-n-butyl acrylate copolymer (copolymerization weight ratio - 65:15
:5:15) emulsified dispersion (solid content: 10% by weight) 50
After adding 300 parts by weight of the above core material particles 1 to 0 parts by weight and sufficiently dispersing them, spray drying was performed at an inlet temperature of 180°C and an outlet temperature of 60°C to coat the surface of the core material particles with the above copolymer. A capsule toner powder was obtained.

To 50 parts by weight of this capsule toner powder, 0.4 parts by weight of hydrophobic silica fine powder "Aerosil R-972J (manufactured by Nippon Aerosil Co., Ltd.) was added and mixed to obtain a capsule toner according to the present invention. Let it be "toner 1".

(3) Preparation of developer 950 is a resin-coated carrier obtained by coating the surface of copper-zinc ferrite particles with the above weight part of toner 1 and a styrene-methyl methacrylate copolymer (copolymerization weight ratio = 70:30). A developer was prepared by mixing parts by weight.

This will be referred to as "Developer 1".

(4) Actual photocopying test Using the above developer 1, an electrophotographic copying machine rU-Bix
1600j (manufactured by Konishiroku Photo Industry Co., Ltd.) to form and develop an electrostatic latent image, and conduct a live copying test in which the resulting toner image was transferred onto transfer paper and then fixed by a heated roller fixing device to form a copy image. The following items were evaluated.

■Minimum fixing temperature After creating an unfixed image using the above copying machine, a heat roller with a diameter of 30φ whose surface layer is made of Teflon (polytetrafluoroethylene manufactured by DuPont) and a silicone rubber surface layer rKE-1300RTVJ (Shin-Etsu Chemical A toner image of the sample toner was transferred onto a 64 g/m'' transfer paper using a heat roller fixing device consisting of a pressure roller (manufactured by Kogyo Co., Ltd.) at a linear speed of 70 mm/sec and a linear pressure of 0.
．． The fixing operation at 8 kg/cm and a nip width of 4.9 mm is repeated at each temperature by increasing the set temperature of the heat roller in steps of 5 degrees Celsius within the range of 100 to 240 degrees Celsius. Apply Kimwipe rubbing against the
The lowest set temperature for a fixed image exhibiting sufficient abrasion resistance was defined as the lowest fixing temperature. Note that the heat roller fixing device used here does not have a silicone oil supply mechanism. The environmental conditions were normal temperature and pressure (temperature 20°C, relative humidity 60%) and low temperature and low humidity (temperature 10°C).

The relative humidity was 40%).

■Offset occurrence temperature Offset occurrence temperature is measured in accordance with the above minimum fixing temperature measurement, but after creating an unfixed image with the above copier,
The toner image is transferred and fixed using the heat roller fixing device described above, and then a blank transfer paper is sent to the heat roller fixing device under the same conditions and visually observed to see if toner stains occur on it. The operation was repeated while the set temperature of the heat roller of the heat roller fixing device was successively increased, and the lowest set temperature at which toner staining occurred was taken as the offset generation temperature. In addition, the environmental conditions are normal temperature and normal pressure (temperature 20
℃, relative humidity 60%) and low temperature and low humidity (temperature 10℃, relative humidity 40%).

(2) Fixable Temperature Range The difference between the offset generation temperature and the minimum fixing temperature measured as described above was defined as the fixable temperature range.

■Blocking resistance The blocking resistance test was conducted at a temperature of 55℃ and a relative humidity of 6.
The toner was left under 0% environmental conditions for one day and judged based on whether or not agglomerates were formed in the toner. If no agglomerates were observed, it was marked "○", and if agglomerates were observed, it was marked "x". And so.

■Environmental conditions are low temperature and low humidity (temperature 10℃, relative humidity 40%)
Durability of the fuser under low temperature and low humidity (temperature 10°C, relative humidity 40%)
Set the temperature of the fixing device 10℃ higher than the above minimum fixing temperature.
We conducted many live-action tests with high temperature settings, and found that the heat roller was dirty, the cleaning roller for the heat roller was dirty, the pressure roller was dirty, offset occurred, paper jam occurred, and the back side of the transfer paper was dirty. The durability of the fixing device was evaluated.

■Fog “Sakura Densitometer” (manufactured by Konishiroku Photo Industry Co., Ltd.)
The determination was made by measuring the relative density of a white background portion with a document density of 0.0 with respect to the developed image. Note that the white background reflection density was set to 0.0. For evaluation, if the relative concentration is less than 0.01, it is marked as "○", and if it is 0.01 or more and less than 0.03, it is marked as "○".
Cases of 0.03 or more were marked as "x".

(2) Image Quality A live copying test was conducted 30,000 times continuously using the above-mentioned copying machine, and the sharpness of the copied image at the initial stage of image formation and at the final stage of image formation was examined. The evaluation was rated "○" if it was good, "△" if it was not good but still at a practical level, and "x" if it was inferior and had problems in practical use.

■Cleanability A live copying test was conducted 30,000 times using the above-mentioned copying machine, and each time the number of copies reached 5,000, the surface of the photoreceptor was visually observed after being cleaned by the cleaning blade. Judgment was made based on the presence or absence of deposits. The evaluation was rated "○" if it was good, "△" if it was not good but still at a practical level, and "x" if it was inferior and had problems in practical use.

■ Filming resistance After carrying out 30,000 continuous tests using the copying machine mentioned above, the surface of the carrier particles, the surface of the photoreceptor, and the cleaning blade were each observed using an electron microscope or visually, and the presence or absence of adhesion was determined by I judged it. When no deposits were observed, it was marked as "○", when some deposits were observed, it was marked as "△", and when a considerable amount of deposits were observed, it was marked as "x".

The above results are shown in Table 1 below.

<Example 2> (1) Production of core material particles 100 parts by weight of the above resin B, 10 parts by weight of carbon blank "Mogull LJ (manufactured by Cabo Soto)," and fatty acid ester wax "Hoechstwax E" (melting point T
mp: 85°C, 10 parts by weight of Hoechst) and polypropylene [Viscol 660PJ (softening point Ts
p: 130°C, manufactured by Sanyo Chemical Industries, Ltd.) were treated in the same manner as in Example 1 to obtain core material particles. This will be referred to as "core material particle 2."

(2) Production of outer shell Capsule toner powder was obtained in the same manner as in Example 1, except that the core particles 2 described above were used.

A capsule toner according to the present invention was obtained in the same manner as in Example 1 except that this capsule toner powder was used. this"
"Toner 2".

(3) Preparation of developer A developer was prepared in the same manner as in Example 1, except that the above Toner 2 was used. This will be referred to as "Developer 2".

(4) Photo-photography test A photo-photography test was conducted in the same manner as in Example 1, except that the developer 2 described above was used and the number of image formations was 50,000 times, and each item was evaluated. The results are also shown in Table 1 below.

<Comparative Example 1> A developer was prepared in the same manner as in Example 1, except that core material particles 1 obtained in the same manner as in Example 1 were used as a toner (hereinafter referred to as "Comparative Toner 1"). Using this developer, a photographic test was conducted in the same manner as in Example 1, and each item was evaluated. The results are also shown in Table 1 below.

Comparative Example 2> 100 parts by weight of comparative resin a and carbon black
10 parts by weight of Mogul LJ (manufactured by Cabo Soto) were treated in the same manner as in Example 1 to obtain core material particles for comparison.

A comparative capsule toner (hereinafter referred to as "comparative toner 2") was produced in the same manner as in Example 1 except that these core particles were used.

) was obtained.

A developer was prepared using this comparative toner 2 in the same manner as in Example 1, and a photographic test was conducted using this developer in the same manner as in Example 1, and each item was evaluated. The results are also shown in Table 1 below.

As understood from the results in Table 1, toner 1 of the present invention
and 2, both have excellent low-temperature fixing properties, particularly sufficient low-temperature fixing properties even under low-temperature, low-humidity environmental conditions, and have excellent anti-offset properties within the fixable temperature range. is wide, ranging from 110 to 115°C. In addition, the anti-blocking property is good, and clear copied images without fogging can be obtained even after 30,000 copy tests, and the cleaning property and filming resistance are also good. Furthermore, even under low temperature and low humidity environmental conditions, there is no dirt on the heated roller, and the image forming process can be carried out smoothly without problems such as paper jams. The heat roller does not become stained even after rotation, and the durability of the heat roller fixing device can be significantly improved. Further, by performing fixing using a heat roller made of fluororesin, the durability of the heat roller fixing device can be further improved.

On the other hand, Comparative Toner 1 does not have an outer shell, so it has sufficient low-temperature fixing properties, but its anti-blocking properties are poor, resulting in poor triboelectric charging properties with the carrier. The copied image becomes foggy and unclear. In addition, the cleaning properties and filming resistance are poor, and the durability is low. In addition, under low temperature and low humidity environmental conditions, heat roller stains occur significantly.
As a result, paper jams occur and it is difficult to perform the image forming process smoothly.

Claims (1)

[Scope of Claims] 1) A capsule toner for heat roller fixing comprising meltable core particles and an outer shell made of a thermoplastic resin provided to cover the surface of the core particles, comprising: Monomers in which the particles contain a divalent alcohol monomer, a divalent carboxylic acid monomer, and a trivalent or higher polyhydric alcohol monomer and/or a trivalent or higher polyvalent carboxylic acid monomer A non-linear polyester obtained by condensation polymerization of body components, characterized by containing a non-linear polyester having a long-chain aliphatic hydrocarbon unit in its main chain and/or side chain, and wax. Capsule toner for heat roller fixing. 2) Glass transition point Tg of non-linear polyester is 40-7
The capsule toner for heat roller fixing according to claim 1, wherein the temperature is 0°C. 3) The capsule toner for heat roller fixing according to claim 1 or 2, wherein the proportion of the non-linear polyester in the meltable core material particles is 50% by weight or more. 4) The capsule toner for heat roller fixing according to any one of claims 1 to 3, wherein the wax has a melting point Tmp of 40 to 120°C. 5) Claim 1, characterized in that the thermoplastic resin forming the outer shell has a glass transition point Tg of 50°C or higher.
The capsule toner for heat roller fixing according to any one of items 1 to 4.