JPH0812461B2 - Heat fixing method and capsule toner for fixing - Google Patents

Description

The present invention relates to a fixing method and a fixing method for fixing a visible image formed by a toner to a recording material in electrophotography, electrostatic printing, magnetic recording and the like. The present invention relates to a capsule toner used.

[Prior Art] Conventionally, as a method for fixing a visible image of toner on a recording material, unfixing is performed by a heating roller maintained at a predetermined temperature and a pressure roller having an elastic layer in pressure contact with the heating roller. The heat roll fixing method in which the recording material holding the toner image is heated while being nipped and conveyed is often used.

Further, a belt fixing method described in USP 3,578,797 is known.

[Problems to be Solved by the Invention] However, in the above-described thermal roll fixing which has been frequently used, there is (1) a time during which the image forming operation is prohibited before the heat roller reaches a predetermined temperature, that is, a so-called wait time.

(2) The heating roller is maintained at an optimum temperature in order to prevent improper fixing and toner transfer to the heating roller, which is a so-called offset phenomenon, due to the temperature of the heating roller fluctuating due to passage of a recording material or other external factors. Must be
For this purpose, the heat capacity of the heating roller or the heating element must be increased, which requires a large amount of electric power.

(3) Since the roller has a low temperature, when the recording material passes through the heating roller and is discharged, the recording material and the toner on the recording material are cooled slowly, so that the adhesiveness of the toner becomes high and In combination with the curvature, a paper jam may occur due to an offset or winding of a recording material.

(4) The high-temperature heating roller comes into direct contact with the hand, which may cause a safety problem or require a protective member. Further, in the belt fixing method described in USP 3,578,797, the problems (1) and (2) of the heat roll fixing described above have not been fundamentally solved.

The object of the present invention is to solve the above-mentioned problems by substantially no or extremely short wait time, low power consumption, no offset phenomenon, and good fixing of a toner image on a recording material. A novel heat fixing method is provided.

Further, an object of the present invention is to provide a heat fixing toner which is preferably used in the heat fixing method provided in the present invention.

Still another object of the present invention is to provide a heat fixing method which does not require a heat resistant special bearing by not using a high temperature rotating roller.

Still another object of the present invention is to provide a heat fixing method which is excellent in safety or does not require a protective member by having a fixing device structure which does not directly touch the high temperature body.

[Means and Actions for Solving the Problems] Specifically, the present invention uses an encapsulated toner in which core particles mainly composed of a resin and a coloring material are coated as a binder resin shell material. In the method of heating and fixing an image on a recording material, a) the binder resin of the shell material is obtained by reacting a polymer formed from at least one or more α, β-unsaturated ethylenic monomers with an organometallic compound. Using a capsulated toner containing the polymer composition prepared as described above, and b) a fixed heating member and a pressure member that is in pressure contact with the heating member and brings the recording material into close contact with the heating member via a fixing film. , the visualized image of the capsule toner and heat-fixing to the recording material, c) conditions the surface temperature T ₃ of the fixing film at a portion separated from the toner fixation surface has a temperature higher than the endothermic temperature T _D of the capsule toner In relates heat fixing method characterized by separating the fixing film from the toner fixation surface.

Further, the present invention provides a visible image of a capsule toner on a recording material by using a fixedly supported heating element and a pressing member which is in pressure contact with the heating element and brings the recording material into close contact with the heating element via a fixing film. heating fixing, under conditions where the surface temperature T ₃ of the fixing film at a portion separated from the toner fixation surface has a temperature higher than the endothermic temperature T _D of the capsule toner is peeled off the fixing film from the toner fixation surface A capsule toner used in a fixing method, the capsule toner comprising core particles mainly composed of a resin and a coloring material coated with a binder resin as a shell material, wherein the binder resin is at least α. , A fixing composition containing a polymer composition obtained by reacting a polymer produced from one or more β-unsaturated ethylenic monomers with an organometallic compound. On Serutona.

In Japanese Patent Application No. 62-147884 previously proposed by the applicant, the toner image is heated by a heat-resistant sheet which is moved by a heating element of low heat capacity which is energized and heated in a pulsed manner, and is fixed on a recording material. Depending on the apparatus, an image forming apparatus with a short wait time and low power consumption has been proposed. Similarly, in Japanese Patent Application No. 63-12069 previously proposed by the applicant, a heat-resistant sheet is separated from a heat-resistant layer in a fixing device that heat-fixes a visible image of a toner on a recording material through the heat-resistant sheet. A fixing device has been proposed which effectively prevents an offset phenomenon by having a mold layer or a low resistance layer.

However, in order to realize a fixing method with a short wait time and low power consumption while achieving excellent fixability of a toner image on a recording material, prevention of offset, etc., in addition to the above fixing device, It depends largely on the characteristics of.

 Hereinafter, the present invention will be described in detail.

The structural feature of the present invention is that the shell material resin of the capsule toner applied in the present invention contains a polymer produced from at least one or more α, β-unsaturated ethylenic monomers and an organometallic compound. It is to contain the polymer composition obtained by reacting. In such a toner, the binder resin reacts with the organometallic compound to be in a state of being crosslinked to some extent, and the offset resistance is remarkably improved. However, the fixing temperature is almost the same as that when the toner is prepared by using the corresponding unreacted polymer.

That is, by using a polymer composition having a slight cross-linking with an organometallic compound, offset resistance while overcoming the disadvantage that a large amount of energy is required for fixing when a polymer cross-linked with a cross-linking agent such as divinylbenzene is used. It becomes possible to improve. Further, the mechanical properties at room temperature are also improved, the impact resistance and toughness are excellent, and as a result, the charging characteristics are stabilized and the developing characteristics as a toner are improved.

Examples of the α, β-unsaturated ethylenic monomer constituting the shell material of the capsule toner applied to the present invention include:
Styrene, styrene such as α-methylstyrene, p-chlorostyrene and its substitution products, acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, actyl acrylate, phenyl acrylate, methacrylic acid, methacrylic acid Methyl acid, ethyl methacrylate, butyl methacrylate, octyl methacrylate,
A monocarboxylic acid having a double bond such as acrylonitrile, methacrylonitrile, acrylamide or the like, or a dicarboxylic acid having a double bond such as maleic acid, butyl maleate, methyl maleate or dimethyl maleate. And its substitution products, for example, vinyl esters such as vinyl chloride, vinyl acetate, vinyl benzoate, etc., vinyl ketones such as vinyl methyl ketone, vinyl excyl ketone, etc., such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl. Vinyl ethers such as ethers Vinyl monomers such as butadiene are used alone or in combination of two or more.

The polymer that reacts with the organometallic compound in the present invention generally includes a carboxyl group, a carbonyl group, an ether group, a thioether group, an amino group, an amide group, and the like.
Among these, the polymer containing a carboxyl group shows the best reactivity. Examples of the carboxyl group-containing monomer for synthesizing the vinyl polymer include acrylic acid,
Acrylic acid such as methacrylic acid, α-ethylacrylic acid and crotonic acid and its α- or β-alkyl derivative, unsaturated dicarboxylic acid such as fumaric acid, maleic acid and citraconic acid and its monoester derivative are available. A desired polymer can be prepared by copolymerizing these monomers, alone or in combination, with the other α, β-unsaturated ethylenic monomer. The ratio of the carboxyl group-containing monomer contained in the polymer is 0.1 to 3
0% by weight gives good results, and in the range of 0.5 to 20% by weight, particularly favorable results are obtained.

As the organometallic compound used in the present invention, those containing the following metal ions can be used, and the metal ions include metal ions having a valence of 1 or more. Suitable monovalent metal ions include Na ⁺ , Li ⁺ , Cs ⁺ , Ag ⁺ , Hg ⁺ , Cu ^+, etc. Suitable divalent metal ions are Be ²⁺ , Mg ²⁺ , Ca ²⁺ , Hg ^{2 +} ,
Sr ²⁺ , Pb ²⁺ , Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Zn ^2+, etc. In addition, suitable trivalent metal ions include Al ³⁺ , Sc ³⁺ , Fi ³⁺ , Co
³⁺ , Cr ³⁺ , Y ^3+, etc. Among the above metal ion compounds, the more decomposable ones give better results. This is presumably because the decomposable one more easily causes the metal ion in the compound to bond with the carboxyl group in the polymer.

The organometallic compound has excellent compatibility and dispersibility with the polymer, and since crosslinking by the metal ions proceeds more uniformly in the polymer, it gives more excellent results. Further, among the above-mentioned organometallic compounds, those containing an organic compound rich in vaporization and sublimation as a ligand or a counter ion are particularly useful. Among the organic compounds that form a coordination or counterion with a metal ion, those having the above-mentioned properties include, for example, salicylic acid, salicylamide, salicylamine, salicylaldehyde, salicylosalicylic acid, ditersialybutylsalicylic acid, and the like. Of salicylic acid and its derivatives, for example, β-diketones such as acetylacetone and propionacetone.

In the present invention, most of the organometallic compounds do not react with the polymer. Therefore, the amount of the organometallic compound to be contained in the toner of the present invention is required to be excessive, and although it depends on the kind of the compound, the amount of the polymer 100 including the unreacted metal compound is almost 100%. It is preferably contained 0.01 to 20 parts by weight with respect to parts by weight, 0.
Particularly good results are obtained with 1 to 10 parts by weight.

The reaction between the vinyl polymer and the metal compound in the present invention is
There are a method of reacting the above metal compound when kneading with a reactive polymer in a roll mill, a method of adding the metal compound to a hot xylene solution of the reactive polymer and reacting. Taking the post-treatment step after the reaction into consideration, the reaction by the melt kneading method is most suitable for the present invention. A toner may be prepared together with other toner materials after preparing the polymer reaction product as a binder by the reaction, or by allowing the reaction itself to be carried out during the heat kneading of the toner material during the toner manufacturing process. Is also good.

Further, the toner of the present invention contains the above-mentioned polymer as a main resin component, and other polymers and resins can be mixed and used as necessary. Other resins that can be mixed and used include vinyl-based polymers composed of monomers that do not contain a carboxy group as a monomer component and those that do not contain vinyl monomers as a monomer component,
For example, polystyrene, poly-p-chlorostyrene, homopolymers of styrene such as polyvinyltoluene, and substituted products thereof; styrene-p-chlorostyrene copolymers, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene copolymers. , Styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene vinyl ethyl Styrene-based copolymers such as ether copolymers, styrene-vinyl methyl ketone copolymers, styrene-butadiene copolymers, styrene-isobrene copolymers, styrene-acrylonitrile-indene copolymers; polyethylene, polypropylene, polychlorinated vinyl Phenol resins, natural resin modified phenol resins, natural resin modified maleic acid resins, acrylic ester resins, methacrylic acid ester resins, polyvinyl acetate, silicone resins, polyester resins, polyurethane, polyamide resins, furan resins, epoxy resins,
Xylene resin, polyvinyl butyral, terpene resin,
Chloroindene resin, petroleum resin, etc. can be used.

The toner used in the heat fixing method of the present invention is a capsule type toner. Generally, the capsule-type toner has a form in which a core material containing a resin, a colorant and the like is coated with a shell material, and the uniform shell material coating has excellent fluidity and charging characteristics. In addition, because it is protected by shell material, blocking property,
It is possible to add a substance having excellent storage stability and softening at a lower temperature to the core material, thereby improving the fixing property and further lowering the substantial fixing temperature.

As the resin material used for the core material of the encapsulated toner of the present invention, various known resins can be used alone or mixed or reacted. For example, polystyrene and its substituted homopolymers: styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, Examples thereof include styrene-based copolymers such as styrene-acrylonitotyl-indene copolymers: acrylic resins, methacrylic resins, silicone resins, polyester resins, furan resins, epoxy resins, and the like.

Furthermore, waxes (beeswax, carnauba wax, microcrystalline wax, etc.), higher fatty acids (stearic acid sun, barmitic acid, lauric acid, etc.), higher fatty acid metal salts (aluminum stearate, lead stearate, barium stearate, stearic acid) Magnesium, zinc stearate, zinc barmitate, etc.), higher fatty acid derivatives (methyl hydroxystearate, glycerol monohydroxystearate, etc.), polyolefins (low molecular weight polyethylene, low molecular weight polypropylene, oxidized polyethylene, polyisobutylene, polytetrafluoroethylene) Etc.), olefin copolymer (ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, ethylene-methacrylic acid copolymer, ethylene-methacrylic acid ester copolymer Ethylene - vinyl chloride copolymers, ethylene - vinyl acetate copolymer, and ionomer resins), rubbers (isobutylene rubber, nitrile rubber,
Chlorinated rubber, etc.), polyvinylpyrrolidone, polyamide,
Coumaron-indene resin, methyl vinyl ether-maleic anhydride copolymer, maleic acid-modified phenol resin,
There are phenol-modified terpene resins and the like, and these can be used alone, mixed, or reacted.

Further, in the core material of the capsule toner of the present invention, in general,
Various dyes and pigments are included as colorants. Examples of such dyes and pigments include carbon black, nigrosine dye, lamp black, Sudan Black SM, First Yellow G, Benzidine Yellow, Pigment Yellow, India First Orange, Irgadine Red, Paranitroaniline. Red, Toluidine Red, Carmine FB, Permanent Bordeaux FFR, Pigment Orange R, Resor Red 2G, Lake Red C, Rhodamine FB, Rhodamine B Lake, Methyl Violet B Lake, Phthalocyanine Blue, Pigment Blue, Brilliant Red. Green B, Phthalocyanine Green, Oil Yellow GG, Suppon First Yellow CGG, Kayaset Y963, Kayaset YG, Sumiplast Yellow GG, Zapon First Orange RR, Oil Scarlet, Sumiplus Orange G, the colorant Orasol Brown B, The Pont Fast Scarlet CG, Aizenspilon Red, BEH, such as oil pink OP can be applied.

Further, in order to use the toner as a magnetic toner, magnetic powder may be contained in the core material. As such magnetic powder, a substance that is magnetized when placed in a magnetic field is used, and is a powder of a ferromagnetic metal such as iron, cobalt, or nickel.
Alternatively, there are alloys and compounds such as magnetite, hematite, and ferrite. The content of the magnetic powder is preferably from 15 to 70% by weight based on the weight of the toner. If desired, either or both of the core material and the shell material of the capsule toner of the present invention may contain a release agent. For example, polyfluorinated ethylene, fluororesin, fluorinated carbon oil, silicone oil, low molecular weight polyethylene, low molecular weight polypropylene, etc. can be used. The addition amount varies depending on either (or both) the core material or the shell material, but it is usually preferable to use 0.1 to 50% by weight, more preferably 0.5 to 20% by weight based on the toner. it can.

The core material of the encapsulated toner of the present invention is obtained by melt-kneading the above components with, for example, a low mill, pulverizing with a jet mill or the like, and classifying with a wind classifier if necessary.

Furthermore, after melt-kneading, the particles are granulated by a spray method, a suspension granulation method, an electrostatic atomization method, or the like, and classified as needed, whereby fine particles having a volume average particle diameter of 20 μm or less are prepared.

As a method for encapsulating these core particles, a known encapsulation technique can be used. For example, a dry capsule method, a spray drying method, a coacervation method, a phase separation method, and the like, in which a shell material is immobilized on the surface of a core material by utilizing mechanical impact force, can be suitably used, in-situ polymerization method, and US patent No. 3,338,991, No. 3,326,848,
The method described in the above-mentioned 3,502,582 specification can also be used.

In some cases, the encapsulated toner of the present invention can be used as a developer after being mixed with a fluidity improver such as colloidal silica, or a lubricant, an abrasive, a charge adjusting agent and the like.

When used as a two-component developer, it is used as a developer after being mixed with an iron powder carrier, a ferrite carrier, a carrier obtained by coating these with a silicone resin, an acrylic resin or the like, or a carrier having a magnetic material dispersed in a resin. .

 Next, the fixing method of the present invention will be described.

First, a schematic structure of an example of the image forming apparatus of the present invention will be described below.
Describing based on the drawings, reference numeral 1 denotes an original placing table made of a transparent member such as glass, which reciprocates in the direction of arrow a to scan the original. A short-focus small-diameter image-forming element array 2 is arranged immediately below the document placing table, and an image of the document placed on the document placing table is illuminated by an illumination lamp 3, and a reflected light image thereof is sensed by the array 2 by the photosensitive drum. 4 is slit exposed. The photosensitive drum 4 rotates in the direction of arrow b. Reference numeral 5 denotes a charger, which uniformly charges the photosensitive drum 4 covered with, for example, a zinc oxide photosensitive layer or an organic semiconductor photosensitive layer. Drum 4 uniformly charged by this charger 5
The element array 2 forms an electrostatic image subjected to image exposure. This electrostatic latent image is visualized by the developing device 6 by using a toner made of a resin or the like which is softened and melted by heating. On the other hand, the sheets P stored in the cassette S
Is fed onto the drum 4 by a pair of conveying rollers 8 which are rotated in pressure contact with each other in the vertical direction at a timing synchronized with the feeding roller 7 and the image on the photosensitive drum 4.
Then, the transfer discharger 9 transfers the toner image formed on the photosensitive drum 4 onto the sheet P. After that, the sheet P separated from the drum 4 by the known separating means is guided to the fixing device 11 by the conveyance guide 10 and subjected to heat fixing processing, and then discharged onto the tray 12. In addition,
After transferring the toner image, the residual toner on the drum 4 is removed by the cleaner 13.

 FIG. 2 shows an enlarged view of the fixing device 11 of this embodiment.

Reference numeral 20 denotes a low-heat-capacity linear heating element that is fixedly supported by the apparatus, and as an example, an alumina substrate 21 having a thickness of 1.0 mm, a width of 10 mm, and a longitudinal length of 240 mm is coated with a resistance material 22 in a width of 1.0 mm. Power is applied from both ends. Energization is a pulsed waveform with a cycle of 20 msec of DC 100 V and is given by varying the pulse width according to a desired temperature and energy release amount controlled by the temperature measuring element 23. Approximate pulse width is 0.5 msec to 5 ms
It becomes ec. When the temperature detected by the temperature measuring element 23 in the low heat capacity linear heating element 20 is T ₁ , the surface temperature T ₂ of the film 24 facing the resistance material 22 is about 10 to 30 ° C. lower than T ₁ . The film surface temperature T _{3 at} the portion where the film 24 is peeled off from the toner fixing surface is substantially equal to the temperature T ₂ .

In this manner, the fixing film 24 moves in the direction of the arrow in the drawing, which is in contact with the heating body 20 whose energy and temperature are controlled. As an example of this fixing film, a heat-resistant film having a thickness of 20 μm, for example, polyimide, polyetherimide, PES, PFA is coated with a release layer made of a fluororesin such as PTFE or PAF to which a conductive material is added at least 10 μm on at least the image contact surface side. It is an endless file. The total thickness is more than 100μ, preferably less than 40μ. The film drive is driven roller 25 and driven roller 26
It moves without wrinkles in the direction of the arrow by the drive and tension.

Reference numeral 27 denotes a pressure roller having a rubber elastic layer having a good releasability such as silicon rubber, which presses a heating body through the film at a total pressure of 4 to 20 kg to rotate in pressure contact with the film.

The unfixed toner 29 on the transfer material 28 is guided to the fixing portion by the entrance guide 30 and obtains a fixed image by the above-mentioned heating.

Although the endless belt has been described above, as shown in FIG. 2B, the sheet feeding shaft 31 and the winding shaft 32 may be used, and the fixing film may be the end film 24.

Image forming devices include copiers, printers and fax machines.
This is applicable to all fixing devices that form an image using toner such as.

The toner used in the heat fixing method of the present invention is
As a result of measuring with DSC in the measuring range from 10 ° C to 200 ° C,
A toner having a maximum value of the endothermic peak that appears first at 40 ° C. to 120 ° C. is preferable, and a toner having characteristics at 55 ° C. to 100 ° C. is particularly preferable.

Furthermore, it is preferable that the fixing film temperature T ₃ at which the peeling from the toner fixing surface at a temperature higher than the endothermic temperature T _D, 30 ° C. or higher than more preferably the endothermic temperature T _D (more preferably 40 It is preferable to peel under high conditions.

In the capsule toner formed of the polymer composition in which the shell material of the capsule toner is crosslinked with the organometallic compound, the crosslinking reaction further progresses by heat during heat fixing. In particular, the capsule toner present on the surface layer of the toner fixing surface is more likely to undergo a crosslinking reaction than the capsule toner of the lower layer, so that the toner fixing surface is easily separated from the fixing film. Further, when the surface temperature T ₃ of the fixing film is lower than the heat absorption temperature T _D of the capsule toner, it becomes difficult for the fixing film to be peeled from the toner fixing surface smoothly, so that the surface state of the toner fixing surface becomes unsatisfactory. It tends to be uniform, and the adhesion force between the surface of the fixing film and the toner fixing surface increases, so that defective separation of the recording material from the fixing film easily occurs.

The maximum value of the endothermic peak in the present invention is calculated according to ASTM D-3418-82. Specifically, 10 to 15 mg of the toner is sampled, heated from room temperature to 200 ° C under a nitrogen atmosphere at a temperature rising rate of 10 ° C / min, held at 200 ° C for 10 minutes, and then rapidly cooled to remove the toner in advance. After the treatment, hold it again at 10 ° C for 10 minutes and heat it to 200 ° C at a heating rate of 10 ° C / min to measure. Generally, the data shown in FIG. 4 is obtained, and the maximum value of the endothermic peak that appears first is defined as the endothermic temperature (T _D ) in the present invention.

The polymer that reacts with the organometallic compound in the present invention is a solution of one or more α, β-unsaturated ethylenic monomers containing at least a monomer containing a carboxyl group, a carbonyl group, an ether group, an amino group, and an amide group. Polymerization method,
It is obtained by polymerization by a polymerization method such as an emulsion polymerization method, a suspension polymerization method or a bulk polymerization method.

Next, the method of immobilization will be described. In the toner, it is preferable that the crushed pieces of the core material and the wall material are not liberated, and that the wall material that has been attached at one end is re-released even in a small amount, so that it is reliably fixed. It is important to modify the configuration of the crusher to extend the residence time of the powder in this crushing process, and to control the impact force in the range where the core material is not crushed and the temperature in the range where fusion does not occur. Is. As an example, a crusher that impacts between a rotating blade or hammer and a liner and has a recycling mechanism (see FIG. 3-1) is effective. The peripheral speed of the tip of the blade or hammer is 30 to 130 m / sec,
Immobilization is preferably performed at 30 to 100 m / sec, and the temperature varies depending on the physical properties of the core material and the wall material, but is 10 ° C to 100 ° C, preferably 20 ° C.
~ 90 ° C, more preferably 30 ° C to 70 ° C. The residence time of the portion to be impacted is preferably 0.2 seconds to 12 seconds. In the case of a pin mill, it is necessary to increase the powder concentration, but
-In the type of machine shown in Fig.-1, the latitude is wide because the powder processed by centrifugal force is collected near the liner.

The device shown in FIGS. 3-1 and 3-2 has a rotary shaft 30.
1, rotor 302, dispersion blade 303, rotating piece (blade) 30
4, partition disk 305, casing 306, liner 307, impact part
308, inlet chamber 309, outlet chamber 310, return passage 311, product extraction valve 312, raw material input valve 313, blower 314, and jacket 3
It consists of fifteen.

 The details will be described with reference to FIG.

The core material particles having wall material particles are introduced from the introduction port 312, pass through the inlet chamber 309, pass through the impact portion 308 between the blade 304 and the liner 307 rotating along the rotating dispersion vane 303, and pass through the outlet chamber 310. Street, return road 311 and blower 314
The circuit is circulated again through.

In FIG. 3-2, the gap a between the rotating piece (blade) 304 and the liner 307 is the minimum gap, and the width b of the rotating piece 304.
The space corresponding to is the impact part.

The gap between the pin mills or between the blade or hammer and the liner is preferably about 0.5 to 5 mm, more preferably 1 mm to 3 mm. In the pin mill, good results can be obtained by setting the minimum gap between the pins to 5 to 10 mm or less, preferably 5 mm or less.

In the toner obtained as described above, a small amount of agglomerates of the wall material particles and fine particles of 5 μm or less and deposits of the wall material are generated. Therefore, in some cases, these may cause fog or white streaks in the image or may cause reduction in the image density during the endurance of a large number of sheets, and may not be allowed depending on the matching with the photoconductor or the copying machine.

If a classification step is further performed after the immobilization to remove fine powder and coarse powder, better image quality can be obtained. Although any of various methods is effective as this classification step, a centrifugal force classifier type machine or a fixed wall type centrifugal force classifier using a rotating blade having a dispersing ability can be used. In particular, a classifier with a Coanda block using the Coanda effect (US
A favorable effect can be obtained with Patent No. 4,132,634).

[Examples] The present invention will be described in more detail with reference to specific examples below.
The present invention is not restricted by this embodiment.
The number of parts means parts by weight.

<Production Example 1 of resin material for shell material> Styrene-maleic acid-divinylbenzene copolymer (Mw = 6.4 × 10 ⁴ copolymerization ratio 95: 5: 0.5) 100 parts Chromium (III) salt of salicylic acid 2 parts The mixture was melt-kneaded using a roll mill, cooled and then pulverized to obtain a shell resin fine powder having an average particle size of 1.0 μm using an air classifier.

<Production Example 2 of resin powder for shell material> Styrene-butyl methacrylate-methacrylic acid-divinylbenzene copolymer (Mw = 1.810 ⁵ copolymerization ratio 75: 22.5: 2: 0.5) 100 parts Nigrosine dye 3 parts Acetylayaton iron III 1 part From the above mixture, fine shell resin powder having an average particle size of 1.0 μm was obtained in the same manner as in Production Example 1 of shell fat powder.

<Sample A> 50 parts of polyethylene, 30 parts of polypropylene, 60 parts of magnetic material The above mixture was melt-kneaded, cooled, and coarsely pulverized with a cutter mill. After further pulverizing with an I-type jet mill, classification with an elbow jet classifier was performed to obtain an average particle size of 10
Core material particles of 5 μm were obtained.

Next, after mixing 40 parts of the shell resin powder with 100 parts of the core material in a Henschel mixer, a dry capsule device shown in FIG. 3-1 was used to circulate for 6 minutes and the peripheral speed of the stirring blade was 60 m / m. The core material particles were encapsulated with the shell resin powder 1 under the conditions of sec, ambient temperature 35 ° C. and shortest gap 2.5 mm.

Colloidal silica 0.5 is added to 100 parts of the obtained capsule toner.
A part was added externally to obtain a sample A.

<Sample B> In the same manner as in Sample A, the core material particles used in Sample A were encapsulated with shell material resin powder 2.

Colloidal silica 0.5 is added to 100 parts of the obtained capsule toner.
The parts were externally mixed and used as sample B.

<Sample C> Polyethylene 100 parts Carbon black 5 parts The above mixture was melt-kneaded using a roll mill, cooled, coarsely pulverized by a cutter mill, and further finely pulverized by a jet mill. Next, this fine powder was classified using an air classifier to obtain core material particles having an average particle size of 10.5 μm.

In the same manner as in Sample A, the upper core material particles were encapsulated with the shell resin powder 1. Obtained Capsule Toner 10
0.5 part of colloidal silica was externally added to 0 part of the mixture to prepare sample C.
And

Sample A on 100 parts of acrylic coated ferrite carrier
10 parts were mixed to obtain a two-component developer.

Next, a fixing test was conducted using the heat fixing devices shown in Samples A to C and FIG. 2 (a). Further, a blocking property test was also conducted.

<Embodiment 1> In this fixing device, the surface temperature of the heating element is 175 ° C., the power consumption of the resistance material in the heating portion is 150 W, and the total pressure of the pressure roller is
7kg, nip between pressure roller and film is set to 3mm, fixing processing speed (ps) is set to 100mm / sec. As a heat resistant sheet, a low resistance release layer with conductive material added to PTFE on the contact surface with the recording material. A 20 μm thick polyimide film having

At this time, the time required to reach the surface temperature of the heating element of 175 ° C was about 1.6 seconds.

Sample-A was applied to a commercial copying machine Canon NP150Z (manufactured by Canon Inc.), which was an improved machine without the fixing machine, to obtain an unfixed image.

This unfixed image was subjected to a fixing test under the above conditions using an external fixing machine as shown in FIG. 2 (a).

As the transfer material, commercially available Canon New Dry Paper (manufactured by Canon Sales Company) 54 g / m ² was used.

In the fixing test, a solid black portion of 20 mmφ in the obtained fixed image was rubbed with a sillbon paper applied with a load of 50 g / cm ² , and the image density reduction rate (%) before and after the rubbing was expressed. A Macbeth reflection densitometer was used to measure the image density. Further, the unfixed image taken out from the modified machine is continuously passed through the external fixing tester in order to check the offset resistance, and the fixing film and the opposing roller are stained, the image is removed by the offset, and the transfer material is transferred onto the image. Judgment was made by observing dirt and dirt on the back side of the transfer material.

As a result, the fixing property was as good as 1 to 8% (average 2.5%) at the initial stage and after passing 200 sheets. As for the offset resistance, neither stains on the transfer paper nor stains on the back side of the transfer paper were observed at all even after passing 10,000 unfixed images. Further, when the film of the fixing device and the surface of the facing roller were observed after continuous paper passing, almost no toner adhered.

Furthermore, when 10 g of this toner was placed in a 100 cc cup made of polypropylene in an oven at a tank temperature of 45 ° C. (constant), the mixture was allowed to stand for 1 day and the blocking property was confirmed. It was good.

Comparative Example 1 The following test was attempted in order to compare the present heat fixing device with the heating roller fixing device. An external fixing device for fixing with a heat roller was prepared. The heat roller fixing device is composed of two rolls, an upper roller and a lower roller, the surface of the upper roller is Teflon, a heater is arranged at the center thereof, and the lower roller is made of silicon rubber. Furthermore, the nip width is 3 mm. The total pressure between the rollers was 7 kg.

When the temperature was raised at the center of the heat roller while rotating a roller with a heater having a power consumption of 150 W, the surface temperature rose to 160 ° C. even after 5 minutes and the fixing test could not be carried out. Therefore, the heater was changed to 900W so that the surface temperature of the fixing roller could be maintained at 175 ℃ or higher. At this time, it took 25 seconds for the temperature of the heat roller surface to rise from room temperature to 175 ° C., and it took some time to keep the temperature at a constant temperature by temperature control. That is, the heat roll fixing requires extremely large power consumption, and the wait time cannot be eliminated.

The fixing test was carried out using the heat roller external fixing tester equipped with this 900 W heater, with the fixing roller oil application mechanism and cleaning mechanism removed.
The fixing processing speed was 100 μm / sec, which was the same as in Example 1.

As a result, the fixability was 2 in the initial stage and after 200 sheets, the density decrease
-10% (4.5% on average), which is slightly inferior to that of Example 1. When 200 sheets were passed, a dropout on the image was already seen due to the offset phenomenon, and after 2400 sheets, the backside was smeared on the transfer sheet. did. Further, when the roller surface was observed after continuous paper passing, a considerable amount of toner had adhered.

<Example 2> In Example 1, a fixing test was conducted by changing the fixing processing speed to 150 mm / sec. However, the surface temperature of the heating element is 180 ° C
It was set to become. At this time, the surface temperature of the heating
The time required to reach 0 ° C was about 1.6 seconds. The results of the fixing test are shown in Table 1. The good results are shown in Table 1.

<Comparative Example 2> The external fixing tester using the hot roll used in Comparative Example 1 was used, and the fixing processing speed was 150 mm / se for comparison with Example 2.
c, and the roller surface temperature was set to 180 ° C.
At this time, the time required for the roller surface temperature to reach 180 ° C. was about 27 seconds plus a little time.

The results are shown in Table 1. As shown in Table 1, the results are inferior in fixing property and offset property.

<Example 3> Using toner sample B, a fixing test and a toner blocking test were performed in the same manner as in Example 1. Table 1 summarizes the test conditions and test results.

Comparative Example 3 Using toner sample B, a fixing test was performed in the same manner as in Comparative Example 1. Test conditions and test results
It is summarized in Table 1.

<Example 4> Using toner sample C, a fixing test and a toner blocking test were performed in the same manner as in Example 1. Table 1 summarizes the test conditions and test results.

<Comparative Example 4> Using toner sample B, a fixing test was performed in the same manner as in Comparative Example 1. Test conditions and test results
It is summarized in Table 1.

Table 2 shows the endothermic temperature (T _D ) by DSC, the heating body temperature (T ₁ ), the film surface temperature (T ₂ ), and the film surface temperature at the time of peeling (T ₃ ) of the toner sample shown in the examples of the present invention.
Shown in

[Advantages of the Invention] As described above, according to the heat fixing method of the present invention, an image having good fixability with less offset and less power consumption was obtained.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an image forming apparatus having a fixing device that carries out the fixing method of the present invention, and FIG. 2 (a) shows a fixing device for carrying out the fixing method of the present invention. FIG. 2 (b) shows a schematic sectional view of a fixing device for carrying out the fixing method of another embodiment of the present invention.
FIG. 3-1 is a diagram schematically showing an example of an apparatus for immobilizing particles on core particles, and FIG. 3-2 is a partially enlarged view of the apparatus of FIG. 3-1. FIG. 4 is a graph showing the endothermic peak of the toner.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location G03G 15/20 101 (72) Inventor Satoshi Matsunaga 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (56) References JP 59-68766 (JP, A) JP 59-157678 (JP, A) JP 57-178249 (JP, A) JP 57-178251 (JP, A) JP-A-57-178250 (JP, A) JP-A-62-295072 (JP, A)

Claims (4)

[Claims] 1. A capsule toner comprising core particles mainly composed of a resin and a coloring material coated as a binder resin shell material,
In a method of heating and fixing a visible image of the capsule toner on a recording material, a) a polymer in which the binder resin of the shell material is formed from at least one or more α, β-unsaturated ethylenic monomers, and an organometallic compound. Using a capsulated toner containing the polymer composition obtained by reacting b) with a fixed heating body, and a recording material is brought into close contact with the heating body through pressure contact with the heating body and a fixing film. The pressing member heats and fixes the visible image of the encapsulated toner on the recording material, and c) the surface temperature T ₃ of the fixing film at the portion separated from the toner fixing surface is higher than the endothermic temperature T _{D of the} encapsulated toner. A heating and fixing method, characterized in that the fixing film is peeled off from the toner fixing surface under the conditions. 2. The heat fixing method according to claim 1, wherein the fixing film is a heat resistant film having a release layer on the toner fixing surface side. 3. The heating element is a linear heating element having a temperature measuring element and a resistance material in the length direction, and while the temperature is detected by the temperature measuring element, energization in a pulsed waveform is applied to the resistance material to heat the heating element. The heat fixing method according to claim 1, wherein the body is heated. 4. A visible image of a capsule toner is recorded on a recording material by a fixedly supported heating element and a pressing member that is in pressure contact with the heating element and presses the recording material to the heating element through a fixing film. heating fixing, under conditions where the surface temperature T ₃ of the fixing film at a portion separated from the toner fixation surface has a temperature higher than the endothermic temperature T _D of the capsule toner is peeled off the fixing film from the toner fixation surface A capsule toner used in a fixing method, the capsule toner comprising core particles mainly composed of a resin and a coloring material coated with a binder resin as a shell material, wherein the binder resin is at least α. , A heat-fixing capsule containing a polymer composition obtained by reacting a polymer produced from one or more β-unsaturated ethylenic monomers with an organometallic compound. Toner.