JPH0232368A - Low temperature and light pressure fixing method - Google Patents

Abstract

PURPOSE:To improve the low heat fixing property and the offset resistance by fixing a specific capsule toner onto the surface of a transfer material by a fixing means in which a surface temperature of a fixing roller is 60-100 deg.C, and also, linear pressure is 5-15kg/cm. CONSTITUTION:A capsule toner which is covered with a core material containing a resin component whose glass transition temperature is <=60 deg.C and whose softening point is 60-130 deg.C is fixed onto the surface of a transfer material by a fixing means in which a surface temperature of a fixing roller is 60-100 deg.C, and also, linear pressure is 5-15kg/cm. In such a way, a satisfactory low heat fixing property and an offset resistance are attained by the core material, and simultaneously, general toner characteristics such as a coagulating property, a blocking property, a developing property, etc., can be attained by a shell material.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application to Which the Invention Pertains] The present invention' relates to a method for fixing microcapsule type toner used in electrophotography, electrostatic printing, magnetic recording, and the like.

[Description of prior art]

Usually, in electrostatic photography, electrostatic printing, or magnetic recording processes, copy images are created by developing an electrostatic latent image formed on a photoreceptor drum using a substance on powder ink called toner, and then transferring it. A method is used in which the image is transferred to a recording medium such as plain paper or OHP paper in a process, and then the transferred image is fixed to the surface of the recording medium in a fixing process. An unfixed image formed on a recording medium is retained but not fixed in a stable state, so generally a method is used to fix the image using the action of a solvent, pressure, heat, etc. .

Among these, in the heat fixing step, a method called a heat roll fixing method in which a constant pressure is applied between opposing rolls and at least one of them is heated is effective.

This heat roll fixing method is advantageous in terms of lower power consumption and higher speed than other flash fixing methods and oven fixing methods that do not use pressure contact or conveyance. It is the most commonly used because it is characterized by low risk. As the heating roll that constitutes the heat roll fixing device, the surface of the cylindrical core metal is coated with a heat-resistant resin such as fluororesin, and as the opposing roll, the surface of the cylindrical core metal is coated with heat resistant resin such as fluororesin so that an effective nip width is formed. Those coated with a heat-resistant elastic material such as silicone rubber or fluororubber are used. However, the heat-resistant resin generally has poor thermal conductivity, so when continuous copying is performed, a large amount of heat is rapidly lost from the surface of the heating roll, which tends to result in insufficient heat supply from the heat source. The surface temperature of the roll decreases, making it easy to cause fusing failure. Furthermore, the higher the speed of fixing, the more heating energy is required, and in particular, high-speed fixing is desired in order to improve the efficiency of copying operations using recent office automation equipment.

In order to increase the fixing speed with the conventional heat fixing method,
Attempts have been made to lower the softening point of the toner binder resin to facilitate heat fixing, but lowering the softening point of the resin causes problems such as agglomeration of toner particles and blocking during use. arise. Thus, there is a strong desire for a toner that is suitable for constant fixation on a hot roller at higher speeds, has no roller offset, and has excellent toner properties such as aggregation and blocking.

Furthermore, since the roll and the toner image come into contact during fixing, some of the toner is transferred onto the roll surface, resulting in staining of the roll surface and staining the trailing edge of the recording medium or the next fed medium. is likely to be re-transferred and fixed onto the backing material, a so-called offset phenomenon. As a countermeasure to this problem, a release agent such as silicone oil is regularly or intermittently supplied and applied to the surface of at least one roll, but this complicates the application equipment and increases the size of the roll.Furthermore, the release agent stains the paper. Or,
Problems such as mold release material spilling are occurring frequently.

On the other hand, as described in Japanese Patent Publication No. 51-23354, such an offset phenomenon tends 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
The fixing temperature increases and a low temperature offset problem occurs in the unfixed area.

In the case of a conventional simple pulverization method toner, it is difficult to balance the conflicting elements of high-speed fixing performance, toner blocking resistance, and caking resistance, and the current situation is that a certain compromise must be found.

As a method for solving many of the problems described above, a microcapsule type heat fixing toner has been proposed for the purpose of high speed heat fixing or low heat energy consumption.

This type of capsule toner uses a low melting point component that is more easily melted by heat as the core material, and a film material that has a high melting point.
In addition, it uses components that have characteristics such as chargeability and fluidity necessary for a toner.
Publication No. 8 includes examples of polystyrene capsules using wax as a core material or polystyrene capsules using an aqueous solution as a core material.

However, to date, a microcapsule toner in which the core particles, which are effective in low-temperature fixability and anti-offset effects, are sufficiently coated with a film material that contributes to development to a practical extent has not been put to practical use. One of the reasons for this is that a material that is easy to encapsulate the core particles does not necessarily provide good development suitability as a toner, particularly good charge controllability, and the range of material selection is extremely narrow.

In addition, there are problems such as the wall material peeling off due to the impact force received during the development process, and there are many issues that need to be resolved in order to put microcapsule toner into practical use, such as the completeness of the coating and the durability of the coating. What remains is the current situation.

Conventionally, many manufacturing methods have been proposed to solve these problems. (Tasushi Kondo, "Microcapsules") For example, a spray dryer method, an electrostatic coalescence method, an in-liquid drying method, an interfacial polymerization method, a phase separation method, an in-5itu polymerization method, and a combination method thereof are disclosed.

In the encapsulation process, the core particles are dispersed in a solution in which the membrane material is dissolved or dispersed, and the dispersion liquid is discharged using a two-fluid nozzle or a disc atomizer, and the shell material is coated on the surface of the core particles. When a spraying method is employed, a capsule toner having a coarse particle size in which the particles coalesce may be obtained, or particles called free shells consisting only of film material may be produced as a by-product. When an interfacial polymerization method is used in the encapsulation process, the reaction generally takes a long time, resulting in a decrease in productivity. Furthermore, since the range of materials that can be used in the interfacial polymerization method is very narrow, it is extremely difficult to appropriately control the characteristics of the capsule toner obtained using the interfacial polymerization method, such as triboelectric charging characteristics. .

Furthermore, even when a phase separation method is used in the encapsulation process, there are various problems. The phase separation method described here shows sufficient solubility in membrane materials. By adding a non-solvent, which is substantially insoluble to the membrane material, to the so-called good solvent solubilized solvent, the shell material is added to the surface of the core particle which has been dispersed or solubilized in the good solvent. This is a method of coating the In this method, it is necessary that the binder constituting the core particles is not substantially dissolved in the good solvent during the process of dispersing the core particles in the good solvent. If a portion of the core material were to be solubilized, the core material would be mixed into the resulting acid film, resulting in destabilization of triboelectric charging characteristics and contamination of the sleeve. Furthermore, once the solubilized core material is precipitated by the action of a non-solvent, a capsule toner containing no colorant and having an extremely high tripodity is produced as a by-product, which is likely to cause problems such as burr and sleeve unevenness. Furthermore, in the phase separation method, selection of a good solvent and non-solvent for the membrane material is extremely important.

In other words, if the selection is incorrect, the membrane material will be deposited too quickly, resulting in poor product stability and reproducibility.On the other hand, if the deposition point is too late, the equipment will become thicker, leading to a decrease in productivity.

[Purpose of the invention]

An object of the present invention is to provide a method for fixing heat-fixable toner that solves the above-mentioned problems. A further object of the present invention is to provide a fixing method for low-temperature, light-pressure fixing that is particularly good in fixing and has good anti-offset properties.

A further object of the present invention is to provide a method for fixing a toner for low-temperature, light-pressure fixing, which has good chargeability and always exhibits stable chargeability during use, and provides clear, fog-free images.

Furthermore, the object of the present invention is to have excellent fluidity, not cause agglomeration,
The present invention provides a method for fixing toner for low temperature and light pressure fixing that has excellent impact resistance.

A further object of the present invention is to provide a method for fixing toner for low-temperature, light-pressure fixing in which less deposits adhere to the surface of a toner holding member or photoreceptor.

Another object of the present invention is to provide a method for fixing microcapsule toner that does not cause adhesion or agglomeration and has high coating integrity (and excellent functional separation).

[Summary of the Invention] The present invention is characterized by a capsule structure that achieves low heat fixing properties and anti-offset properties with the core material, and at the same time achieves some toner properties such as cohesiveness, blocking properties, and developability with the membrane material. It has a heat-fixable toner composition.

In the heat-fixable toner with a capsule structure related to the present invention, the core material is a material with a low Tg that could not be used alone due to its blocking properties, cohesive properties, etc., and also has good anti-offset properties. to share most of the functions of heat fixing properties, and to use a material that has toner properties such as developability and storage stability of dry toners as well as or better than conventional toners as a membrane material, making it a so-called function-separated type. Thus, the objects of the present invention were achieved.

Specifically, the present invention has a glass transition temperature (Tg of 606
A capsule toner coated with a core material containing a resin component having a softening point of 60 to 130 °C and a fixing roller surface temperature of 60 to 100 °C and a linear pressure of 5
The present invention relates to a low-temperature, light-pressure roller constant fixing method characterized in that fixing is carried out on the surface of a transfer material using a fixing means of ~15 kg/cm.

[Detailed description of the invention]

The core material used in the present invention has a glass transition temperature (
It is desirable to have a Tg) of 60°C or less and a softening point of 60 to 130°C. If the Tg exceeds 60°C or the softening point exceeds 130°C, excessive thermal energy will be required during heat fixing.
High-speed heat fixing performance deteriorates. If the softening point is less than 60° C., the offset resistance during fixing will be poor. Specifically, polyethylene wax, polyethylene oxide, paraffin, higher fatty acid, higher fatty acid ester, higher fatty acid amide, higher fatty acid metal salt, higher alcohol, ethylene-vinyl acetate copolymer, silicone oil, fluorocarbon oil, polyester resin. , epoxy resin, styrene
Acrylic copolymers, styrene-butadiene copolymers, cyclized rubbers, etc. can be used alone or in combination of two or more, or by reacting them, as core material raw materials to provide these core materials.

The core particles used in the present invention can be manufactured by various manufacturing methods using the core material as described above. As a method for producing such core particles, for example, known dry and wet toner production methods can be used as they are. For example, in the dry manufacturing method, polyester resin, styrene resin, and other compounds are mixed in advance into fine particles, mixed uniformly by hot melt mixing, and then air jet pulverized, wind classifier, etc. are used to form cores of a constant particle size. A method for obtaining particles, an electrostatic atomization method using the method described in JP-A-58-216736 in which a DC voltage is applied and core material is discharged from a disk atomizer, and a special method in which core particles are formed using a two-fluid nozzle. Melt spray method described in JP-A-59-120263,
The suspension granulation method described in JP-A-59-127062, which involves granulation in an aqueous medium, is preferably used. The suspension granulation method is preferably a method in which the core material is granulated in an aqueous medium under normal pressure or under increased pressure to produce core particles, since the particle size distribution becomes sharp.

For example, when using a method of granulating core particles using a poorly water-soluble dispersant in an aqueous medium, the dispersant dissociates in the aqueous medium and induces a charge, and imparts cationic properties that induce an opposite charge. It is preferable to use a combination of compounds or anionicity-imparting compounds. When obtaining core particles in an aqueous medium in the presence of a poorly water-soluble dispersant, it is common to use a dispersant having a sufficiently small particle size relative to the core particles to be obtained.

In other words, when the particle size of the dispersant is very small, the surface of the dispersant particles is significantly activated energetically, which increases the selective adhesion of the dispersant particles onto the surface of the core particle.

In the present invention, when a polar solvent such as water is used as a dispersion medium for the core particles, it is advantageous to provide the dispersant with a highly polar functional group. By occupying, due to ionic ability interaction,
Furthermore, it becomes possible to make the core particles as desired. Furthermore, by making effective use of such functional groups, it is expected that, for example, the dispersant can be removed when it is not needed. In other words, if it is desired to obtain a desired particle size, it can be achieved by arbitrarily selecting the amount of the slightly water-soluble dispersant added.

However, simply using a dispersant selected in this way does not necessarily ensure that the dispersant adheres selectively and uniformly only to the surface of the core particle, and may not be sufficient to obtain uniform particles. There is. In order to uniformly adhere the dispersant to the surface of the core particles, it is necessary to add a cationic material that induces a charge opposite to the charge induced by dissociation of the dispersant in the aqueous medium in the core material to be atomized. It is preferable to combine a compound imparting anionic properties or a compound imparting anionic properties.

For example, typical examples of dispersants that can be dissociated as anions in water include silica, bentonite, etc., and hydrophobic amines are generally used as compounds imparting cationic properties to these dispersants. Particularly preferably, as a highly cationic compound that is sufficiently compatible with other components contained in the core substance,
These include long-chain aliphatic amines or grafting compounds made from polyethylene and monomers containing amine groups. Specifically, after heating and dissolving Duomin T (Lion Armor Co., Ltd.) and polyethylene wax, an aprotic polar solvent containing an amino group-containing vinyl monomer and a radical initiator is added, and the mixture is heated again. There are the obtained amino-modified waxes and the like.

On the other hand, examples of dispersants that can be dissociated as cations in water include aluminum oxide. Compounds imparting anionic properties include hydrophobic long-chain aliphatic carboxylic acids such as stearic acid and oleic acid. Further, there are long-chain aliphatic dicarboxylic acids, carboxylic anhydrides, such as reaction products of C8α-olefin and maleic anhydride, or half esters thereof.

In the present invention, when a magnetic substance is contained in the core material, iron or cobalt is used as the magnetic substance.

Ferromagnetic elements such as nickel or manganese, and alloys and compounds such as magnetite and ferrite containing these elements can be used. This magnetic substance may also be used as (all or part of) a coloring agent. Furthermore, the magnetic substance particles may be treated with various hydrophobizing agents (for example, silane coupling agents, titanium coupling agents), surfactants, and the like. The content of this magnetic substance is preferably 15 to 180 parts by weight (more preferably 50 to 150 parts by weight) based on 100 parts by weight of all the resins in the core material.

In the core material of the present invention, a coloring agent can be used in combination with a magnetic material or alone. Examples of such colorants include various types of carbon black.

Examples include aniline black, naphthol yellow, molybdenum orange, rhodamine lake, alizarin lake, methyl violet lake, phthalocyanine blue, nigrosine methylene blue, rose bengal, and quinoline yellow.

The amount of colorant added is based on 100 parts of the binder resin of the core particles.
0.1 to 20 parts is preferred.

Furthermore, the molten mixture of the core material consisting of the binder resin of the core material and the magnetic material (coloring agent if necessary) is heated at 120°C.
The apparent viscosity measured at a shear rate of 10 sec-' is preferably 175 or less of the apparent viscosity measured at a shear rate of 0.5 sec-' from the viewpoint of toner fixability and manufacturing method.

The fact that the apparent viscosity decreases as the shear rate increases is generally referred to as thixotropy, and this highly thixotropic core material promotes toner deformation due to shear during fixing, improving fixing performance. let

Alternatively, as described later, this core material is melt-kneaded, then poured into an aqueous medium, and granulated by applying strong shearing force using a homomixer or the like in the presence of a dispersant, emulsifier, etc. During shearing, the apparent viscosity of the core substance decreases, which improves granulation properties, while after shearing, the apparent viscosity increases, causing coalescence of particles and coloring inside the particles. Aggregation and deviation of agents, magnetic materials, etc. are suppressed.

In addition, resins with good fixing properties generally have a relatively low melt viscosity, so during melt-kneading, shearing force between pigments such as colorants and magnetic substances and the binder resin does not work, and this Therefore, the pigment tends to be insufficiently dispersed in the binder resin. As a result, particles with no coloring material present inside the toner particles,
Alternatively, a large number of particles in which the coloring material in the toner particles is unevenly distributed is generated, which tends to deteriorate the performance as a toner and, in turn, adversely affect the image quality, durability, stability, etc. of the toner.

Therefore, it is desirable to disperse the pigment particles (used to include magnetic particles) in the toner particles so that the particle size is 5 μm or less, preferably 2 μm or less. For this reason, compared to the two-roll, twin-screw extruder kneader, etc. that were conventionally used for melting and dispersing toner components,
It is desirable to melt and mix and disperse for a sufficiently long time using an attritor, ball mill, or sand mill using media.

In order to check the degree of dispersion of pigment substances, you can find out by dispersing the toner in an embedding resin such as epoxy resin, curing it, cutting it into ultrathin sections using a microtome, etc., and observing it using a transmission electron microscope. can. Also, particle size gauge (e.g. grind gauge, type ■ manufactured by Yoshimitsu Seiki Co., Ltd.)
The dispersibility of pigment substances can also be determined by using

Above, the core material used in the microcapsule toner manufacturing method of the present invention has been mainly explained.

The membrane material used in the present invention must have a number average molecular weight of 3,000 to 3,000 in order to have sufficient solubility in the solvent used in the phase separation method and good film-forming properties when the solvent is removed.
A polymer compound that does not have about 30,000 cross-linkages is generally used. Specific examples include resins such as homopolymer copolymers comprising the following monomers.

Styrene (sB, p-chlorostyrene, p-dimethylaminose styrene, and other styrenes and their substituted products; methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate (MMA), ethyl methacrylate, butyl methacrylate ( BMA), methacrylic acid N, N-dimethylaminoethyl ester (DM), acrylic acid N,
N-dimethylaminoethyl ester, methacrylic acid N,
N'-diethylaminoethyl ester (DE), acrylic acid N, N-diethylaminoethyl ester, methacrylic acid 2-piperidinoethyl ester, acrylic acid 2-
Esters or ester derivatives of acrylic acid or methacrylic acid, such as piperidinoethyl ester, 2-methylamino-2-methyl-1-propanol methacrylate, 2-methylamino-2-methyl-1-propanol acrylate, etc. ;Maleic anhydride or half ester, half amide or diesterimide of maleic anhydride, vinylpyridine, vinylcarbazole,
5-ethyl-2-vinylpyridine, 2methyl-5-vinylpyridine, N,N-divinylaniline, trans-1
, 2-bis(2-pyridyl)ethylene, 2-vinylquinoline, 2-(N,N-dimethylamino)-4-vinylbilimicin, 4-vinylpyrimidine, 3-cinnamoylpyridine, 4-methacryloxybenzylideneaniline , diallylmelamine, 2,4-dimethyl-6-vinyl-
Nitrogen-containing vinyls such as triazine, 4,6-diami2-vinyltriazine, and N-vinylimidazole; Vinyl acetals such as vinyl formal and vinyl butyral; Vinyl heptamers such as vinyl chloride, acrylonitrile, and vinyl acetate; Vinylidene chloride and vinylidene fluoride vinylidene monomers such as olefin monomers such as ethylene and propylene. Also, polyester, polycarbonate, polysulfonate, polyamide, polyurethane, polyurea, epoxy resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, melamine resin, polyphenylene oxide Homopolymers, copolymers, or mixtures of polyether resins such as, thioether resins, etc. can be used.

Preferably, a styrene-acrylic acid ester derivative or a styrene-methacrylic acid ester derivative exhibiting sufficient solubility in the solvent used in the phase separation method, good film-forming properties, and stable characteristics against changes in humidity and temperature. Copolymers consisting of vinylidene derivatives and polymers consisting of vinylidene derivatives are particularly preferred.

As mentioned above, it is generally preferable that core particles used for pressure fixing be produced in an aqueous system. The production of the core particles of the present invention is not limited to aqueous systems, but can be carried out by melting, kneading, or
It is also possible to manufacture the product through pulverization (in the atmosphere) and, if necessary, a classification process.

The core material for the heat fixable toner may be one showing rubber elasticity such as styrene-butadiene resin, a polyester resin having a trifunctional or higher functional group, or a resin containing a carboxylic acid group cross-linked with a metal. Products with a three-dimensional network structure, such as those created by mixing crosslinking monomers and creating crosslinks between the main chains, are resistant to thermal offset and have low resistance to heat offset when using a heat roll fuser. By widening the molecular weight distribution by mixing appropriate amounts of molecular weight components, it is possible to keep the fixing temperature relatively low, while also improving thermal offset properties.

As the encapsulation method used in the present invention, a phase separation method is employed. The phase separation method consists of the following steps. That is, a dispersion liquid is prepared by uniformly dispersing solid core particles that are insoluble in the solvent in a solution in which a high molecular weight polymer forming the shell film of the capsule toner is dissolved in a solvent, and the high molecular weight polymer, A non-solvent that has no solubility for the core particles and is freely miscible with the solvent is gradually added to the dispersion and mixed uniformly, thereby enriching the high molecular weight polymer in a good solvent. Minute oil droplets are deposited. The mixing enthalpy of both solvents required for precipitation at this time is 5 K Ca I / m
o 1 or less, and it is necessary to control the precipitation temperature to be below the melting point of the non-solvent. The generated oil droplets gradually gather on the surface of the core particle, resulting in the formation of a liquid phase coating, which is further solidified and then the resulting capsule toner is produced by separating it. The mixing enthalpy of the good solvent and non-solvent in which the shell material was dissolved when the membrane material was precipitated was calculated as follows.

The chemical potential of the system when the membrane material is precipitated by adding a non-solvent to a solution containing the membrane material is expressed as equation (1).

μ=μo+RTI! nX, ・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・ (1) On the other hand,
The mole fraction (X, ) of the nonsolvent is expressed as (2).

To x ・・・・・・・・・・・・・・・
・・・・・・・・・(2) nl +n2 +n3 If we partially differentiate equation (1) with respect to temperature and rearrange the equation, we get (3)
The formula is obtained.

The enthalpy of mixing can be obtained by integrating equation (3), plotting the relationship between l nX H and 1/T, and finding its slope. Specifically, 2.5% of membrane material is used for 10cc of good solvent.
g The solubilized homogeneous solvent is controlled in advance at a constant temperature. The point at which the cloudiness does not disappear by gradually adding a non-solvent to this is called the precipitation point, and the temperature of each solution is -5.
, -10, -20, -30, and -350C were plotted against the temperature and mole fraction of the nonsolvent at the precipitation point, and good linearity was obtained. From the slope, it was possible to determine the temperature when the membrane material was precipitated. The mixing enthalpy of the good solvent and non-solvent in which the membrane material was dissolved was calculated. The results are shown in Table 1. When the mixing enthalpy at the time of precipitation is 5 K Ca 1 / m o 1 or more, the membrane material dissolved in a good solvent is difficult to precipitate even if a large amount of non-solvent is added, and the temperature dependence of precipitation is low. Due to its large size, temperature control is difficult, which is extremely disadvantageous in terms of manufacturing. Preferably, when the membrane material is precipitated, the mixing enthalpy of the good solvent in which the shell material is dissolved and the non-solvent is 0.01 to
A system of 4 K Ca I/mol is effective.

The mixing enthalpy of precipitation is 0, OI K Cal
/ m o less than 1, the membrane material dissolved in a good solvent will precipitate with a small amount of nonsolvent added, making it difficult to control the speed of nonsolvent addition, which is extremely disadvantageous for the reproducibility and stability of encapsulation. be.

In the method of obtaining a capsule toner by the phase separation method, which is a feature of the present invention, it is necessary to control the temperature at which the membrane material is precipitated to be below the melting point of the nonsolvent. If encapsulation is carried out at a temperature above the melting point of the non-solvent, the core material will be solubilized when the core particles are dispersed in a good solvent in advance, and when the non-solvent is added in the next step, the core particles will be free of colorant. The so-called free shell, which does not contain core particles, occurs because encapsulated toner with core particles is produced as a by-product, and the solubilized core material destabilizes minute oil droplets that are generated in the initial stage of precipitation of the film material. Easily generates particles.

Furthermore, in the present invention, it is preferable to control the dispersion rate of the nonsolvent as a good solvent core particle.

Here, A: Concentration of shell material in good solvent (g/ (1), B
: Good solvent amount (I), C: Non-solvent addition rate (mj!/
(minutes), which greatly reduces production efficiency.

This makes it difficult to control the temperature of the dispersion liquid, and also causes coalescence of capsule toners and free shells, which is undesirable.

In the encapsulation process using the phase separation method of the present invention,
It is also possible to use a dispersant and a dispersion aid together in a good solvent in which the membrane material is dissolved. Specific examples include styrene-maleic anhydride copolymer, aliphatic α-olefin
Examples include maleic anhydride copolymers, organic acids, and organic amines.

It is also possible to add or mix various dyes and pigments, hydrophobic colloidal silica, etc. to the capsule toner produced by the production method of the present invention for the purpose of charge control, imparting fluidity, coloring, etc. The volume average particle diameter of the capsule toner is preferably 3 to 20 μm.

More preferably, 8 to 15 μm is effective. The toner preferably contains 1 to 30% by weight of a coloring dye and pigment.
A soft solid core containing ~15% by weight is surrounded by a hard material.
．． The coating has a thickness of 0.01 to 2 μm, preferably 0.1 to 0.6 μm.

The present invention will be explained in more detail by showing specific examples below.

(Example 1) Polypropylene oxide adduct of bisphenol A 56
Put 0 part into a Yotsuro flask, add a stirrer, a condenser,
Set the thermometer and gas inlet tube and place it inside the mantle heater. After replacing the inside of the reaction vessel with nitrogen gas, the contents are 50~
When the temperature reached 60°C, 190 parts of fumaric acid and 0.4 parts of hydroquinone were added, and the mixture was heated to 210°C with stirring.

After about 5 hours have elapsed while continuously removing the reaction water, check the end point of the reaction (the reaction is monitored by measuring the acid value every hour). When the acid value reaches about 50, 0. After adding 3 parts of sorbitol and continuing the reaction until the acid number is approximately 25, the resin is cooled to room temperature.The resin thus obtained had a Tg of 55°C and a softening point of 95°C. .

100 parts by weight of the obtained polyester, 70 parts by weight of magnetic powder (Magnetite EPT-1000 manufactured by Toda Industries), low molecular weight polypropylene (Hiscol 660P manufactured by Sanyo Chemical Industries)
) A mixture consisting of 5 parts was heated and kneaded with a roll. After cooling it, it was crushed to a size of 1 to 2 mm, and then finely pulverized using a jet mill and classified using a wind classifier to obtain a particle size distribution (measured using a Coulter counter).
Number average particle size 9.1μm, volume average particle size 10.5μm1
9 core particles with a volume average particle diameter variation coefficient of 18.7%
Obtained with a yield of 5%. After drying the obtained core particles, use a homomixer in an If flask to sufficiently disperse the following at a solution temperature of -25°C, and then add 1.5 ml of water for 11 minutes while maintaining the temperature in the dispersion. It was dripped gradually. The enthalpy of mixing at this time is 0.4 KCal
/mol. The particle size distribution of the obtained capsule toner was as follows: number average particle size: 9.9 μm 1 volume average particle size: 11.5 μm
It was m.

Further, the variation coefficient of the volume average particle diameter was 18.0%.

This particle size distribution suggests encapsulation with less free shell and less coalescence. In addition, the amount of triboelectric charge of this capsule toner was determined according to U.S. Patent No. 43022.
When measured by the method described in the specification of No. 01, +17
．． It was 0 μcoul/g. From this, it can be understood that the membrane material sufficiently covers the core particles.

Image quality of the obtained toner was evaluated using Canon NP-3525, which is a copying machine capable of multicolor multiplexing using an OPC photoreceptor.

In the NP-3525, during the development process where the electrostatic latent image on the OPC photosensitive drum is turned into a visible image, excess toner adheres to the bright areas of the photosensitive drum (the areas that are exposed to light), causing fog development. In order to prevent this, a constant DC bias Voc higher than the bright area potential VL of the photosensitive drum is applied to the developing sleeve. Further, in order to erase images in designated categories for multiplex/multicolor copying, etc., strong light is applied to the photoreceptor using an LED, a fuse lamp, etc. to prevent the drum potential from decreasing any further, and a bright area potential VSt is applied to the photoreceptor.

For example, in a positively or negatively charged toner, a component that behaves in an opposite polarity is added to the bright area potential vL on the photosensitive drum, and further to the VL area on the photosensitive drum.
It tends to fly to the St part, causing fog. In addition, this anti-polar component increases VDC(!:VSL(7) due to fogging.
) This reduces the possible range (IvDC-vsLl) and narrows the appropriate development area.

As for the machine used for image printing, the fixing unit of this NP-3525 was removed and a new external fixing unit was installed.

This external fixing device has the same configuration as the fixing device of PC-30 (manufactured by Canon), but is improved so that it can heat a part of the surface of the pressure roller. When using the NP-3525, which has an improved fuser configuration like this, and setting the fixing roller surface temperature to 70°C and linear pressure to 7 Kg/Cm, we obtained a clear image with no fog. The solid density was 1.36, and both fixability and offset were sufficient.

Also, there is no reverse fog in the VSL section, (l Voc-V
, SL l ) 220v, and a wide appropriate development area was obtained. In addition, after 10,000 copies were repeatedly made, the variation in solid density was stable at ±0.07, and the reverse fog in the VSt and area was the same as the initial time (no at all, and (l Voc-VSL
l ) (7) The value also remained almost unchanged at 200V.

Furthermore, when the environmental conditions were changed to 35° C. 185% and 15° C. 210%, good images were obtained in both cases, similar to those at normal temperature and normal humidity, and no major changes were observed with durability.

Furthermore, although this capsule toner was left in an atmosphere at 45° C. for a long time, no blocking, caking, etc. were observed.

(Example 2) 2 kg of commercially available carnauba wax (manufactured by Noda Wax Co., Ltd.)
The mixture was placed in a four-bottle flask, and the pressure inside the container was reduced to 1 to 2 mm Hg in a nitrogen atmosphere. While maintaining this reduced pressure state, the inside of the container was heated to 250°C and reacted for 8 hours. The acid value of the carnauba wax obtained at this time was 0.
It was 5.

This carnauba wax (Vickers hardness Hv3.6) 4
00g, Polywax 655 (manufactured by Vetrolite Co., Ltd.: critical surface tension cuff c=31dyne/cm), and 200g, and further 5PO145 (manufactured by Nippon Seiro Co., Ltd., compressive elastic modulus E=1
5Kg/mrd) 400g and 21! After charging into a four-hole flask, n-butyl-4,4-bis-tert
Adding butyl peroxyvalerate (Barhexa V manufactured by Nippon Oil & Fats Co., Ltd., half-life of 10 hours, temperature 105°C) Ig,
The inside of the container was heated to 150°C and heat treated for 2 hours.

Further, the mixture of the above formulation was kneaded at 120'C using an attritor and 20Orpm for 3 hours to obtain a core material.

The kneaded material (core material) had a rubbing speed of 10 at 120°C.
The apparent viscosity of sec-' is 600 cps, and the shear rate is 0.
．． The apparent viscosity at 5 sec was 6500 cps.

In addition, the particle size of magnetite particles in the kneaded material is at most 1.5
It was μm.

On the other hand, in a 201 Ajihomo mixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), water 181 and hydrophilic silica (Aeroseal #200, manufactured by Nippon Aerosil Co., Ltd.) which is negatively ionized in water 2 were placed in advance.
0g was sampled and heated to 90°C to use as a dispersion medium. In the dispersion medium thus obtained, the above kneaded material (core material) IK
g, and the circumferential speed of the above Ajihomo mixer was 20 m/sec.
c. Granulation was performed for 1 hour under the conditions of 6.9 passes/min. After the granulation was completed, the dispersion was cooled to 30° C. using a heat exchanger, and then 50 g of sodium hydroxide was added to the dispersion, and stirring was continued for 5 hours to obtain core particles.

When the obtained spherical core particles were analyzed by fluorescent X-ray analysis, no residual silica was observed.

Furthermore, the core particles are filtered using a centrifuge and washed with water.
Core particles were obtained in which the particle size distribution (measured using a Coulter counter) was 9.1 μm in number average particle size, 10.5 μm in volume average particle size, and 18.7% in the volume average particle size variation coefficient.

Using the above formulation, 100 g of core particles were dispersed in a solution containing the above membrane material at a solution temperature of -25°C or lower in the same manner as in Example 1, and then water was added into the dispersion while maintaining the temperature. It was gradually dropped at a rate of 2.0 mA/min. The mixing enthalpy at this time was 0.6 KCal/mo+. The particle size distribution of the obtained capsule toner (as measured using a Coulter counter) had a number average particle size of 10.1.
μm, and the volume average particle diameter was 11.6 μm. Furthermore, when the amount of triboelectric charge of the capsule toner was measured in the same manner as in Example 1, it was found to be +18.5 μcoul/g. A clear image without fogging was obtained at a density of 1.40, and sufficient fixing performance was obtained at 80° C. and 10 kg/cm, with slight offset. This toner
A blocking test was conducted in an atmosphere at 5°C, but no caking was observed.

(Example 3) In the step of encapsulating by the method described in Example 2,
2.0mj of water while maintaining the temperature during precipitation at -5℃!
A capsule toner was obtained by gradually dropping the powder at a rate of 1/min.

The particle size distribution of the obtained capsule toner was 1 in number average particle size.
The particle diameter was 0.8 μm, and the volume average particle diameter was 12.5 μm. The amount of triboelectric charge of this capsule toner is +16.
It was 5 μcoul/g. When image printing was performed using NP3525 with a modified fixing device in the same manner as in Example 1, a clear image without fog was obtained with a solid density of 1.37, and 80°C and 10K g/cm were sufficient. It exhibited good fixing properties, and both offset and blocking were good.

(Example 4) In the step of encapsulating by the method described in Example 2,
While maintaining the temperature during precipitation at -10°C, water was poured in at 2.0 m, 7
A capsule toner was obtained by gradually dropping the mixture over 77 minutes.

The particle size distribution of the obtained capsule toner was 1 in number average particle size.
The particle diameter was 0.5 μm, and the volume average particle diameter was 12.1 μm. The amount of triboelectric charge of this capsule toner is +16.
It was 9 μcoul/g. Similar to Example 1, NP3
The result of image rendering using 525 is a solid density of 1.3
9.Fog rank is also good, and at 90℃, 8.
The fixing property of K g/cm, offset and blocking were all good.

(Example 5) In the step of encapsulating by the method described in Example 2,
A good solvent is acetone, and the temperature during precipitation is maintained at -25°C while adding 2.0 mI of water! A capsule toner was obtained by gradually dropping the powder at a rate of 1/min. The enthalpy of mixing at this time is 1, 2 K
Ca 1/m o 1. The particle size distribution of the obtained capsule toner was 11.3 μm in number average particle size and 12.6 μm in volume average particle size, and the triboelectric charge amount of the toner was +17
．． It was 4 μcoul/g. Furthermore, when an image was produced in the same manner as in Example 1, a fog-free image was obtained with a solid density of 1.30, and the fixability, offset, and blocking at 80° C. and 10 kg/cm were both good. Ta.

(Comparative Example 1) The core particles used in Example 1 were sufficiently dispersed in a shell material solution which had been previously solubilized in a tetrahydrofuran solvent using a homomixer, and the amount supplied was 10 mj! /min, inlet temperature 1
Spray drying was carried out under conditions of 30° C. and outlet attitude of 85° C. to obtain a microcapsule toner. The particle size distribution of the obtained capsule toner has a number average particle size of 7.8 μm and a volume average particle size of 1 μm.
It was 5.3 μm, and many free shell and toner compounds were co-produced. When the obtained toner was imaged, a decrease in image density was observed with repeated image formation, and
Toner blocking was observed in an atmosphere of 5°C.

(Comparative Example 2) In the encapsulation process according to the method described in Example 2,
A good solvent was DMF, and water was gradually added dropwise while maintaining the precipitation temperature at 10° C. to obtain a capsule toner. The mixing enthalpy at this time was 0.6 KCal/mo+. The particle size distribution of the obtained capsule toner was 12 in number average particle size.
．． The average particle size per volume of 5 μm was 16.5 μm, and as a result of observation under an electron microscope, it was confirmed that many of the toners coalesced. In addition, the amount of triboelectric charge was as low as +8.0 μcoul/g, and although images were printed using the method used in Example 1, the image density decreased significantly due to continuous copying, so a blocking test was conducted in an atmosphere at 45°C. However, caking of the toner was observed.

(Comparative Example 3) Capsule toner was manufactured in the same manner as in Example 1, but for image formation, the surface temperature of the pressure roller in the fixing unit was set to 180°01, and the linear pressure was set to 12 kg/cm.
When I tried setting it to , the resulting image had severe offset and the toner had soaked into the back side of the paper.

(Comparative Example 4) Using the capsule toner described in Example 1, image formation was carried out by setting the pressure roller surface temperature of the fixing unit to 70° C. and the linear pressure to 3 K g/cm. When I tried it, I found that it was thin with a solid density of 0.75, and its fixing properties were insufficient as it peeled off when I rubbed it with my fingers.

Claims (1)

[Claims] (1) A capsule toner coated with a core material containing a resin component having a glass transition temperature (Tg) of 60°C or less and a softening point of 60 to 130°C is coated with a fixing roller surface temperature of 60 to 100°C. , and the linear pressure is 5 to 15 Kg/cm
A low-temperature, light-pressure roller fixing method characterized by fixing onto the surface of a transfer material using a fixing means.