JPH0812458B2 - Heat fixing method and heat fixing capsule toner used in the method - 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. Regarding the toner used.

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

Also, a so-called 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 for which the image forming operation is prohibited until the heat roller reaches a predetermined temperature, that is, a so-called wait time.

(2) In order to prevent fixing failure and transfer of toner to the heating roller due to the temperature of the heating roller fluctuating due to passage of the recording material or other external factors, so-called offset phenomenon, the heating roller is set to an optimum temperature. It is necessary to maintain this, and for this purpose, the heat capacity of the heating roller or the heating body must be increased, which requires a large amount of electric power.

(3) Since the temperature of the roller is low, 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 toner has a high adhesiveness. In combination with the curvature of, the paper may be jammed due to the offset or winding of the recording material.

(4) Since the high-temperature heating roller is in direct contact with the hand, there is a problem in safety or a protective member is required. Also, 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.

An object of the present invention is to substantially eliminate the wait time for solving the above-mentioned problems, or an extremely short time,
Further, the present invention provides a novel heating and fixing method which has low power consumption, does not cause an offset phenomenon, and is excellent in fixing a toner image on a recording material.

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 that 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 in which the high temperature body is not directly touched.

[Means for Solving the Problem] In Japanese Patent Application No. 62-147884 previously proposed by the present applicant, a toner image is generated through a moving heat-resistant sheet by a low heat capacity heating element that is energized and heated in a pulse shape. An image forming apparatus having a short wait time and low power consumption has been proposed by a fixing device that heats an image and fixes it on a recording material. Similarly, Japanese Patent Application No. 63-1206 previously proposed by the applicant.
In 9, in the fixing device for heating and fixing the visible image of the toner on the recording material via the heat resistant sheet, the heat resistant sheet has a heat resistant layer and a release layer or a low resistance layer,
A fixing device has been proposed that effectively prevents the offset phenomenon.

However, in order to realize a fixing method that has a short wait time and low power consumption while achieving excellent fixability of a toner image on a recording material, prevention of offset, etc., the fixing device as described above is used. In addition, the characteristics of the toner largely depend.

The present invention that achieves the above-mentioned object is a method of heat-fixing a visible image of a toner onto a recording material by using a capsule toner in which the surface of core particles containing a binder resin and a colorant as a main component is coated with a resin. The binder resin comprises etherified bisphenols, aromatic dicarboxylic acids of 30 mole% or more in total acid components, alkenyl-substituted dicarboxylic acids and / or alkyl-substituted dicarboxylic acids of 5 to 40% by weight based on total acid amount. A polyester resin having an acid value of 5 to 60 obtained by co-condensing an acid with a polycarboxylic acid having a valency of 3 or more and / or a polyol having a valency of 3 or more, and 0.2 to 6% by weight based on the polyester resin.
Containing an organometallic compound containing a metal having a valence of more than 3, and the binder resin has a melt viscosity η'by an elevated flow tester of 10 ³ to 10 ⁵ poise at the 50% outflow point, and its melt viscosity When the natural logarithm lnη ′ is plotted against temperature, the absolute value of the slope of the graph is 1.0ln (pois
e) Using a capsule toner having a characteristic of not higher than / ° C., b) a fixedly supported heating body, and a pressing member that is in pressure contact with the heating body and that makes a recording material adhere to the heating body through a film. Heat-fixes the visible image of the capsule toner on the recording material, and the film is peeled from the toner-fixed surface at a temperature 30 ° C higher than the maximum value of the endothermic peak measured by the DSC of the toner. Regarding the method.

Further, a fixed image of the toner is heated and fixed on the recording material by a heating member fixedly supported and a pressing member which is in pressure contact with the heating member and brings the recording material into close contact with the heating member via a film. In a toner used in a heat fixing method of peeling a film from a toner fixing surface at a temperature higher than 30 ° C. higher than a maximum value of an endothermic peak measured by DSC, the toner mainly contains a binder resin and a colorant. Which is a capsulated toner in which the surface of core particles is coated with a resin, wherein the binder resin comprises etherified bisphenols, aromatic dicarboxylic acids of 30 mole% or more in the total acid component, and 5% of the total acid amount. Up to 40% by weight of alkenyl-substituted dicarboxylic acids and / or alkyl-substituted dicarboxylic acids and dicarboxylic acid having a valence of 3 or more and / or polyols having a valence of 3 or more The binder resin contains a stell resin and an organometallic compound containing 0.2 to 6% by weight of a metal having a valency of 2 or more with respect to the polyester resin, and the binder resin has a melt viscosity η ′ of 50% flowing out by an elevated flow tester. The characteristic is 10 ³ to 10 ⁵ poise at the point, and when the natural logarithm lnη ′ of the melt viscosity is plotted against temperature, the absolute value of the slope of the graph is 1.0 ln (poise) / ° C or less. And a heat-fixing capsule toner.

 Hereinafter, the present invention will be described in detail.

One feature of the constitution of the heat fixing method of the present invention is that the core binder resin has an etherified diphenol and an aromatic dicarboxylic acid as a basic skeleton, and trivalent or higher polycarboxylic acids and / or trivalent With the above polyols, the polymer skeleton is reticulated, and further an alkenyl-substituted dicarboxylic acid and / or an alkyl-substituted dicarboxylic acid is introduced as a soft segment into the polymer skeleton, and a polyester resin having an acid value of 5 to 60, and the resin. 0.2-6% by weight of 2
By containing at least an organometallic compound containing a metal having a valency or higher, the toner can be heated and fixed on the recording material with low power consumption.

When the soft segment is less than 5% by weight of the total acid content, the power consumption for heat fixing increases, and when it exceeds 40% by weight, the offset property during heat fixing may be poor. .

Polycarboxylic acids, which are reticulating components of the polymer skeleton, are preferably contained in the polyester in an amount of 5 to 30% by weight, and polyols are preferably contained in an amount not exceeding 5% by weight.

When the total amount of polycarboxylic acids and polyols is 40% by weight or more, the crushing cost in the toner manufacturing process increases, and naturally more energy is required to heat and fix the toner.

Conversely, when the total amount of polycarboxylic acids and polyols falls below 10% by weight in polyester, the toner tends to excessively melt in the heat fixing step, and when the amount is 5% by weight or less, the toner is completely immersed in the transfer paper. Defects such as image blurring due to penetration, set-off, and spread of molten toner become remarkable.

Further, as the main component acid component of the polyester of the present invention, 30 mole% or more of the total acid component, more preferably 40 mole
% Or more of aromatic dicarboxylic acids, and as an alcohol component, it is necessary that 80 mol% or more, more preferably 90 mol% or more, etherified bisphenols in all alcohol components are etherified bisphenols from the viewpoint of durability as a toner.

Further, by using the above-mentioned polyester resin as a binder resin and adding a small amount of an organometallic compound in the heat kneading step during the production of a toner, in the heat fixing method of the present invention, it is possible to effectively prevent excessive melting of the toner. Immersion in transfer paper,
It has been found that the set-off and the spread of the molten toner can effectively prevent defects such as image blurring.

According to the study by the present inventors, unlike the reticulated component in the constituent raw material of the polyester resin, the metal ion brings a “weak cross-linking structure” to the toner, and the increase in the power consumption required for fixing is extremely small. . However, the above-mentioned effects of the organometallic compound according to the present invention are as follows: the more aromatic components in the polyester resin, the smaller the acid value of the polyester resin is in the range of 5 to 60. It does not suffer from the drawback of increased power consumption.

Therefore, the addition amount of the metal compound in the present invention is preferably 0.2 to 6% by weight, more preferably 1 to 5% by weight, based on the polyester resin. If it is 0.2% or less, there is no substantial effect, and if it is 6% by weight or more, the power consumption at the time of fixing is increased due to the increase of the heat capacity of the toner itself as in the case of adding a large amount of the inorganic filler.

In the constitution of the heat fixing method of the present invention, yet another feature is that the above-mentioned specific polyester resin is used as a main binder resin, and the binder resin obtained by containing at least the above-mentioned organometallic compound is a thermally elevated type. The melt viscosity η ′ measured by the flow tester is 10 ³ to 10 ⁵ poise at the 50% outflow point, and the absolute logarithm of the slope of the graph is plotted when the natural logarithm lnη ′ of the melt viscosity in that temperature range is plotted. Value is 1.0l
When n (poise) / ° C. or less, the toner can be fixed on the recording material with lower power consumption without offsetting to the film.

The melt viscosity of the present invention was measured using an elevated flow tester (Shimadzu flow tester CFT-500 type) as shown in FIG. A 1.5 g sample molded using a pressure molding machine was applied with a load of 10 kgf with a plunger at a constant temperature so that it was pushed out from a nozzle with a diameter of 1 mm and a length of 1 mm. speed)
To measure.

This outflow rate is measured at each temperature (interval of 2.5 ° C), and the apparent viscosity η'can be obtained from this value by the following equation.

However, η ′: Apparent viscosity (poise) Tω ′: Apparent shear reaction of tube wall (dyne / cm ² ) Dω ′: Apparent shear rate of tube wall (1 / sec) Q: Outflow rate (cm ³ / sec = ml / sec) P: Extrusion pressure (dyne / cm ² ) [10kgf = 980 × 10 ⁴ dyn
e] R: Nozzle radius (cm) [0.1 cm] L: Nozzle length (cm) [0.1 cm] Plot the natural logarithm of the apparent viscosity η'obtained from the flow tester against temperature (° C) Then, the slope at the temperature of the 50% pour point was calculated. The 50% outflow point is
Performed by the flow tester, heating the sample at a temperature rising rate of 4 ° C / m
It is the temperature at the time when the load of 10 kgf is applied while heating at in, and the outflow amount from the nozzle becomes 50 wt%.

In the present invention, the “slope” of the viscosity at the 50% pour point means, as shown in FIG. 5, the measurement points (t _c and t _d ) of the melt viscosity that sandwich the temperature (t ₅₀ ) at the 50% pour point. Connect the plots at the outer measurement points (t _a and t _b ) with a straight line, It is calculated from the above, and this is approximated and used as the “slope” of the slope. (However lnη _'a represents a value obtained by taking the natural logarithm of the viscosity at _{t a (℃), lnη'} b denotes a value at t _b (° C.). The measurement was measured 5 ° C. intervals.) The present invention The "viscosity" and "inclination" of the binder resin in the heat fixing method of 1 are peculiar to each binder resin,
It shows the sensitivity of the viscosity of the binder resin to temperature, and is involved in the binder property and toner particle deformation during the formation of a fixed image. Particularly in the fixing method using a film, the correlation with the fixing process is great. When melt viscosity is high (10 ⁵
Poise or more) causes less particle deformation during heat fixing and does not increase adhesiveness, which causes fixing failure, and a large amount of energy is required to compensate for this. On the other hand, when it is low (10 ³ poise or less), bleeding on the transfer paper or penetration into the transfer paper is likely to occur. Also “tilt”
If the value becomes too large (1.0 ln (poise) / ° C or more), the particles are sensitive to temperature and exhibit a rapid change in viscosity, so the fixing temperature latitude cannot be sufficient and improper fixing and penetration occur. easy. Furthermore, the fixing processing speed (mm / se
Greater dependency on c). Further, this "tilt" is also involved in the viscosity change during cooling after melting of particles during fixing, and when the "tilt" is large, the offset phenomenon to the film increases.

The usable etherified diphenols, which are the constituent raw materials of the polyester resin as the binder resin applied to the present invention, are polyoxystyrene (6) -2.2-bis (4-hydroxyphenyl) propane, polyoxystyrene (6) -2. Hydroxybutylene (2) -2.2-bis (4-hydroxyphenyl) propane, polyoxyethylene (3) -2.2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3) -bis (4- Hydroxyphenyl) thioether, polyoxyethylene (2) -2,6-dichloro-4-hydroxyphenyl, 2 ', 3', 6'-trichloro4'-hydroxyphenylmethane, polyoxypropylene (3) -2-bromo -4-hydroxyphenyl, 4-hydroxyphenyl ether, polyoxyethylene (2,5) -p.p-bi Phenol, polyoxybutylene (4) bis (4-hydroxyphenyl) ketone,
Polyoxystyrene (7) -bis (4-hydroxyphenyl) ether, polyoxypentylene (3) -2.2
-Bis (2.6-diaiodo-4-hydroxyphenyl) propane and polyoxypropylene (2.2) 2
-2-bis (4-hydroxyphenyl) propane.

One group of etherified diphenols are etherified bisphenols. A preferred group of etherified bisphenols are ethoxylated or propoxylated, having 2-3 moles of oxyethylene or oxypropylene per mole of bisphenol and having R as propylene or sulfone groups. An example of this group is polyoxyethylene (2.5) -bis (2.6-dibromo-).
4-hydroxyphenyl) sulfone, polyoxypropylene (3) -2,2-bis (2.6-difluoro-4-)
Hydroxyphenyl) propane and polyoxyethylene (1.5) -polyoxypropylene (1.0) -bis (4-hydroxyphenyl) sulfone.

Another preferred group of etherified bisphenols falling into the group characterized by the above formula is polyoxypropylene 2.2 · 2′-bis (4-hydroxyphenyl) propane and polyoxyethylene or polyoxypropylene 2
And 2-bis (4-hydroxy, 2.6-dichlorophenyl) propane (the number of oxyalkylene units is 2.1 to 2.5 per mol of bisphenol).

Aromatic carboxylic acids that are constituent raw materials of the polyester resin of the present invention include terephthalic acid, isophthalic acid, phthalic acid, diphenyl-p.p'-dicarboxylic acid,
Naphthalene-2,7-dicarboxylic acid, naphthalene-2.
6-dicarboxylic acid, diphenylmethane-p · p′-dicarboxylic acid, benzophenone-4 · 4′-dicarboxylic acid,
1,2-diphenoxyethane-p.p'-dicarboxylic acid or the like can be used, and other acids include maleic acid, fumaric acid, glutaric acid, cyclohexanecarboxylic acid, succinic acid, malonic acid, adipic acid, mesaconic acid. , Citraconic acid, sebacic acid, and anhydrides of these acids.

Examples of the alkenyl-substituted dicarboxylic acid or alkyl-substituted dicarboxylic acid that is a constituent raw material of the polyester resin of the present invention include maleic acid, fumaric acid, adipic acid, and succinic acid substituted with an alkenyl group or an alkyl group having 6 to 18 carbon atoms. Examples thereof include acids, glutaric acid, sebacic acid, azelaic acid and their anhydrides and esterified products.

In particular, n-dodecenyl succinic acid, isododecenyl succinic acid, n-dodecyl succinic acid, iso-dodecyl succinic acid,
Iso-octyl succinic acid, n-octyl succinic acid, n-
Butyl succinic acid and the like are preferable.

The tricarboxylic or higher polycarboxylic acids which are the constituent raw materials of the polyester resin of the present invention include trimellitic acid, pyromellitic acid, cyclohexanetricarboxylic acids, 2.5.
-Naphthalene tricarboxylic acid, 1,2,4-naphthalene tricarboxylic acid, 1,2,4-butane tricarboxylic acid,
1,2.5-hexanetricarboxylic acid, 1.3-dicarboxyl-2-methylenecarboxylic propane, 1.3
-Dicarboxyl-2-methyl-2-methylenecarboxylic propane, tetra (methylenecarboxylic) methane, 1,2,7,8-octanetetracarboxylic acid and their anhydrides, esterified products and the like can be used. As trihydric or higher polyols, sorbitol, 1, 2, 3, 6
-Hexanthetol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1,2,4-mesitatriol,
Glycerin, 2-methylpropanetriol, 2-methyl-1,2.4-butanetriol, trimethylolethane, trimethylolpropane, 1,3.5-trihydroxymethylbenzene, erythro1.2,3-butanetriol, Examples include threo 1, 2, 3-butanetriol and the like.

The organometallic compound usable in the toner of the present invention is 2
Examples thereof include organic salts or complexes containing a metal having a valence of 3 or more. Effective metal species are Al, Ba, Ca, Cd, Co, Cr,
Examples include polyvalent compounds such as Cu, Fe, Hg, Mg, Mn, Ni, Pb, Sn, Sr, and Zn. As the organic metal compound, carboxylate salts, alkoxylates, organic metal complexes, and chelate compounds of the above metals are effective, and examples thereof include zinc acetate, magnesium acetate, calcium acetate, aluminum acetate, magnesium stearate, calcium stearate, stearin. Examples thereof include aluminum acid acid, aluminum isopropoxide, aluminum acetylacetate, iron (II) acetylacetonate, and 3,5 ditertiary butyl chromium stearate. Acetylacetone metal complexes and salicylic acid metal salts are particularly preferable.

In the binder resin used in the present invention, in addition to the polyester resin composed of the above-mentioned constituent materials, the melt viscosity η'by the overhead flow tester is 10% at the outflow point in a proportion smaller than the content of the polyester resin. ^It does not deviate from ³ to 10 ⁵ poise, and the natural logarithm of its melt viscosity (ln
η ′) is plotted against temperature so that the absolute value of the slope of the graph does not exceed 1.0 ln (poise) / ° C., for example, a vinyl resin mainly composed of styrene, styrene-
Butadiene resin, silicone resin, polyurethane resin,
Polyamide resin, epoxy resin, polyvinyl butyral resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc. may be contained. .

If desired, the core material of the capsule toner of the present invention may contain various release agents. For example, polyfluorinated ethylene, fluororesin, fluorinated carbon oil, silicone oil,
Low molecular weight polyethylene, low molecular weight polypropylene and the like are used in an amount of 0.1 to 10% by weight based on the toner.

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 FRR, 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, Zapon First Yellow CGG, Kayaset Y963, Kayaset YG, Sumiplast Yellow GG, Zapon First Orange RR, Oil Scarlet, Sumipras 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.

The core material of the encapsulated toner of the present invention can be obtained by melt-kneading the above components with, for example, a roll mill, pulverizing with a jet mill or the like, and, if necessary, classifying with an air classifier. Furthermore, after the particles are melt-kneaded, they are granulated by a spray method, a suspension granulation method, an electrostatic atomization method, or the like, and classified as necessary, 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, spray drying method, coacervation method, phase separation method and the like can be preferably used, in-situ polymerization method, U.S. Pat.
No. 8,991, No. 3,326,848, No. 3,502,58
The method described in the specification No. 2 and the like can also be used.

A known resin can be used as the shell material. For example, there are resins composed of the following monomers. Styrene such as styrene, P-chlorostyrene, and P-dimethylamino-styrene and substituted products thereof; methyl acrylate,
Ester of acrylic acid or methacrylic acid such as ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, methacrylic acid N, N-dimethylaminoethyl ester; maleic anhydride or malefic acid harfester, Half amide or diester imide, vinyl pyridine, N
-Nitrogen-containing vinyl such as vinyl imidazole; vinyl acetals such as vinyl formal and vinyl butyral; vinyl monomers such as vinyl chloride, acrylonitrile, vinyl acetate; vinylidene monomers such as vinylidene chloride and vinylidene fluoride; olefin monomers such as ethylene and propylene. is there. Also, polyester, polycarbonate, polysulfonate, polyamide, polyurethane, polyurea, epoxy resin, rosin, modified rosin,
Homopolymers or copolymers of terpene resins, phenol resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, melamine resins, polyether resins such as polyphenylene oxide or thioether resins, or copolymers, and further Mixtures thereof can be used.

The encapsulated toner of the present invention can also be used as a developer after optionally mixing a fluidity improver such as colloidal silica, or a lubricant, an abrasive, a charge control agent and the like.

When used as a two-component developer, an iron powder carrier, a ferrite carrier, or a carrier obtained by coating these with a silicon resin, an acrylic resin, or the like, or a carrier in which a magnetic material is dispersed in a resin, or the like is mixed with the developer. Used as.

 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 rotates in the direction of arrow b. Reference numeral 5 denotes a charger, which uniformly charges the photosensitive drum 4 coated with, for example, a zinc oxide photosensitive layer or an organic semiconductor photosensitive layer. The drum 4 uniformly charged by the charger 5 is
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 are
It 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. afterwards,
The sheet P separated from the drum 4 by a known separation unit is guided to the fixing device 11 by the conveyance guide 10 and is heated and fixed, and then discharged onto the tray 12. After the toner image is transferred, the residual toner on the drum 4 is removed by the cleaner 13.

FIG. 3 shows an enlarged view of the fixing device 11 of the present invention. Reference numeral 20 denotes a low-heat-capacity linear heating element fixedly supported by the apparatus, and as an example, an alumina substrate having a thickness of 1.0 mm, a width of 10 mm, and a longitudinal length of 240 mm.
Resistance material 22 is applied to 21 to have a width of 1.0 mm, and electricity is applied from both ends in the longitudinal direction. 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 the desired temperature and the amount of energy released controlled by the temperature measuring element 23. The approximate pulse width is 0.5 msec to 5 msec. When the temperature detected by the temperature measuring element 23 in the low heat capacity linear heating element 20 is T ₁ , a film facing the resistance material 22.
The surface temperature T _{2 of} 24 is about 10-30 ° 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 way, the fixing film 24 moves in the direction of the arrow in the drawing by coming into contact with the heating body 20 whose energy and temperature are controlled. As an example of this fixing film, a heat-resistant film with a thickness of 20 μm,
For example, it is an endless film obtained by coating a release layer of polyimide, polyetherimide, PES, PFA with a conductive material added to a fluororesin such as PTFE, PAF or the like on at least the image contact surface side to a thickness of 10 μm. Generally, the total thickness is 100μ, preferably 40μ
Less than, 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 is 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. 3 (b), a sheet feeding shaft 31 and a winding shaft 32 may be used, and the fixing film may be an 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.

In the heat fixing method of the present invention, the toner used has a maximum value of the endothermic peak first appearing from 40 ° C. to 120 ° C. as a result of measurement by DSC in a measuring range from 10 ° C. to 200 ° C.
A toner having a temperature of 55 ° C. is preferable, and a toner having a characteristic of 55 ° C. to 100 ° C. is particularly preferable.

Further, the temperature at the time of peeling the film from the toner fixing surface is 30 ° C. or more (more preferably 40
It is better to peel under high conditions.

The maximum value of the endothermic peak in the present invention is calculated according to ASTM D-3418-82. In particular,
10 to 15 mg of toner is sampled from room temperature to 200 ° C under a nitrogen atmosphere.
After heating at a temperature rising rate of 10 ° C / min to 200 ° C for 10 minutes, and then rapidly cooling the toner to pretreat it in advance, and then hold it again at 10 ° C for 10 minutes, then 10 ° C / min. min
Measure at a heating rate of up to 200 ℃. 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.

[Examples] Hereinafter, the production examples of the polyester resin used in the examples and comparative examples of the present invention and the production examples of the capsule toner using the resin as the core binder resin will be described, but the present invention is not limited thereto. Not something to do. The number of parts means parts by weight.

(Production Example of Polyester Resin a) A total of 1500 kg of the above constituent raw materials was placed in a 2-liter four-neck round bottom flask equipped with a thermometer, a stainless steel stirrer, a glass nitrogen introducing tube, and a downflow condenser. Then place the flask in the mantle heater,
Nitrogen gas was introduced through the glass introduction tube to maintain the inside of the reactor in an inert atmosphere and raise the temperature.

Thereafter, 0.01 g of dibutyltin oxide was added and the temperature was maintained at 210 ° C. to obtain a polyester resin a which was subjected to a cocondensation reaction for 12 hours.

100 parts of the above polyester resin and 2 parts of an organometallic compound (chromium complex of 3,5 ditertiarybutylsalicylate) are mixed and melt-kneaded by a twin-screw kneading extractor (kneading temperature 160 ° C.)
Then, a polyester resin a was obtained. The viscosity of this resin measured by an elevated flow tester at a 50% outflow point is 1.3 × 10 ⁴ poise, and the slope of the natural logarithm of the viscosity with respect to temperature is 0.11n.
(Poise) / ° C.

(Production Example of Polyester Resin b) A polyester resin was obtained in the same manner as the above polyester resin except that the above constituent materials were used. The acid value of this resin was 21.5.

Next, 100 parts of this polyester resin and 3 parts of an organometallic compound (acetylacetone iron) were mixed and melt-kneaded (kneading temperature 160 ° C.) with a biaxial kneading extruder to obtain a polyester resin b. The viscosity of this resin measured by an elevated flow tester at a 50% outflow point was 8.8 × 10 ³ poise, and the slope of the natural logarithm of the viscosity with respect to temperature was 0.12 ln (poise) / ° C.

(Sample A) 100 parts of the polyester resin a and 60 parts of the magnetic material according to the above-described production example were melt-kneaded, pulverized and classified to obtain core material particles having an average particle diameter of 10.8 μm.

 The core material particles were encapsulated by the following method.

The core material particles were dispersed in a 3% aqueous solution of gelatin and stirred for 5 minutes to form a gelatin shell material having a thickness of 0.8 μm. Next, an insoluble layer was passed through this portion, washed with ethanol and dried to obtain an intermediate layer around the core material.
100 parts of the obtained particles were dispersed in a solution having the following composition.

This dispersion was encapsulated using a spray dryer (inlet temperature 150 ° C., outlet temperature 100 ° C., air volume 10 m / min, 2-fluid nozzle type). This obtained capsule toner 100
0.6 part of colloidal silica is externally added and mixed to the sample
I got

(Sample B) 100 parts of the polyester resin b according to the above-described production example and 60 parts of the magnetic material were melt-kneaded, pulverized and classified to obtain core material particles having an average particle diameter of 11.0 μm.

The core material particles were encapsulated in the same manner as in Sample A.
0.5 part of colloidal silica was externally added to and mixed with 100 parts of the obtained capsule toner.

 This is sample B.

(Sample C) 100 parts of polyester resin a and 4 parts of Pigment Blue were kneaded, pulverized and classified in the same manner as in Sample A to obtain an average particle size of 1
1.2 μm core material particles were obtained.

 The core material particles were encapsulated by the following method.

A core material particle dispersion liquid containing the above components was prepared. A 28% aqueous ammonia solution was gradually added dropwise to this dispersion until the pH of the system became alkaline, and encapsulation was performed. At this time, the temperature inside the tank was 15 ° C. and the rotation speed was 4000 rpm (auto homomixer).

 Then, it was dried over and dried to obtain a capsule toner.

Colloidal silica for 100 parts of this capsule toner
Sample C was prepared by externally mixing 0.5 parts.

100 parts of resin-coated ferrite carrier was mixed with 10 parts of sample C to prepare a two-component developer.

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

<Embodiment 1> In this fixing device, the surface temperature of the heating element is 170 ° C., the power consumption of the resistance material in the heating portion is 150 W, the total pressure of the pressure roller is 7 kg, the nipple between the pressure roller and the film is 3 mm, and the fixing process is performed. The speed (ps) was set to 100 mm / sec. As the heat-resistant sheet, a polyimide film having a thickness of 20 μm having a low-resistance release layer in which a conductive material was added to PTFE was used on the contact surface with the recording material.

At this time, the time required until the surface temperature of the heating body reached 170 ° C. was about 1.5 sec.

Sample A was applied to an improved machine of the commercial copying machine Canon NP-1215 (manufactured by Canon Inc.) from which the fixing device was removed to obtain an unfixed image.

This unfixed image was subjected to a fixing test under the above conditions using an external fixing device as shown in FIG. 3 (a).

A commercially available Canon New Dry Paper (manufactured by Canon Sales Co.) 54 g / m ² was used as the transfer material.

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 fixability was as good as 2 to 5% (average 3.1%) at the initial stage and after passing 200 sheets. Further, the offset resistance was such that, even after passing 10,000 unfixed images, neither stain on the transfer paper nor stain on the back side of the transfer paper was observed at all. 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, 10 g of this toner was placed in a polypropylene 100 cc cup in an oven with a tank temperature of 45 ° C (constant).
When the toner containing the toner was left for 1 day and the blocking property was observed, no toner lumps were generated and 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 a heater with power consumption of 150 W was attached to the center of the heat roller and the temperature was raised while rotating the roll, the surface temperature rose to 150 ° C. even after 4 minutes, and the fixing test could not be performed. Therefore, the heater was changed to 900W so that the surface temperature of the fixing roller could be maintained at 170 ℃ or higher. At this time, the time required for the surface temperature of the heat roller to rise from room temperature to 170 ° C. was 23 seconds, and it took some time to maintain the temperature at a constant temperature by adjusting the temperature. In other words, the heat roll requires extremely large power consumption, and the wait time cannot be removed.

The fixing test was performed using a heat roll external fixing tester equipped with a 900 W heater, with the oil applying mechanism and the cleaning mechanism of the fixing roller being removed. The fixing processing speed was 100 mm / sec, which was the same as in Example 1.

As a result, the fixability was slightly inferior to that in Example 1 as the density reduction rate was 3 to 7% (average 4.8%) at the initial stage and after 200 sheets, and when 200 sheets were passed, the image was already developed by offset development. The paper was seen to be missing, and the backside was smeared at 3,500 sheets. 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 130 mm / sec. However, the surface temperature of the heating element is 190 ℃
It was set to become. At this time, the surface temperature of the heating element is 19
The time required to reach 0 ° C was about 1.7 sec. The results of the fixing test are shown in Table 1. Good results were shown as 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 130 mm / se for comparison with Example 2.
It was changed to c and the roller surface temperature was set to 190 ° C.
At this time, the time required for the roller surface temperature to reach 190 ° C. was about 30 seconds.

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 shown in ble.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 C, a fixing test was performed in the same manner as in Comparative Example 1. Test conditions and test results
It is shown in ble.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

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an elevated flow tester for measuring the melt viscosity of a toner or a binder resin, and FIG. 2 is an image forming apparatus equipped with a fixing device for carrying out the fixing method of the present invention. FIG. 3 (a) is a schematic sectional view of the fixing device for carrying out the fixing method of the present invention, and FIG. 3 (b) is a fixing method of another embodiment of the present invention. FIG. 3 shows a schematic cross-sectional view of a fixing device for carrying out the above. FIG. 4 is a graph showing the endothermic peak of the toner, and FIG. 5 is a graph showing the slope of the natural logarithm of the viscosity of the toner or the binder resin with respect to temperature.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number in the agency FI Technical indication location G03G 13/20 15/20 101 (72) Inventor Satoshi Matsunaga 3-30-2 Shimomaruko, Ota-ku, Tokyo No. Canon Inc. (56) Reference JP-A-59-68766 (JP, A) JP-A-59-157678 (JP, A) JP-A 61-278861 (JP, A) JP-A 59-9669 (JP, A) JP 61-215558 (JP, A) JP 61-215557 (JP, A) JP 63-58356 (JP, A)

Claims (2)

[Claims] 1. A method of heat-fixing a visible image of the toner to a recording material by using a capsule toner in which the surface of core particles containing a binder resin and a colorant as a main component is coated with a resin, and a) the binder resin. However, (a) etherified bisphenols, (b) 30 mole% or more of aromatic dicarboxylic acids in the total acid component, and (c) 5 to 40% by weight of alkenyl-substituted dicarboxylic acids and / or alkyls based on the total acid amount. A polyester resin having an acid value of 5 to 60, which is obtained by co-condensing a substituted dicarboxylic acid with (d) a polycarboxylic acid having a valence of 3 or more and / or a polyol having a valence of 3 or more, and 0.2 to 6% by weight of the polyester resin. An organic metal compound containing a metal having a valence of 2 or more is contained, and the binder resin is
The melt viscosity η ′ measured by an elevated flow tester is 10 ³ to 10 ⁵ poise at the 50% outflow point, and the natural logarithm lnη ′ of the melt viscosity is plotted against temperature. Using a capsulated toner having a value of 1.0 ln (poise) / ° C or less, b) a fixed and supported heating element, and a recording material that is in pressure contact with the heating element and is in close contact with the heating element via a film. The pressing member heats and fixes the visible image of the encapsulated toner on the recording material, and peels the film from the toner-fixed surface at a temperature 30 ° C or more higher than the maximum value of the endothermic peak measured by the DSC of the toner. Characteristic heat fixing method. 2. A toner image is heat-fixed on a recording material by 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 film. However, in the toner used in the heat fixing method of peeling the film from the toner fixing surface at a temperature higher than the maximum value of the endothermic peak measured by DSC of the toner by 30 ° C. or more, the toner contains a binder resin and a colorant. A capsule toner in which the surface of core particles as a main component is coated with a resin, wherein the binder resin is (a) etherified bisphenols, and (b) 30 mol% or more aromatic dicarboxylic acids in all acid components, (C) 5 to 40% by weight of the total acid content of alkenyl-substituted dicarboxylic acids and / or alkyl-substituted dicarboxylic acids and (D) trivalent or higher polycarboxylic acids and / or trivalent or higher polyols And containing an organometallic compound containing a divalent or higher valent metal 0.2 to 6% by weight relative to the polyester resin and the polyester resin having an acid value of 5 to 60, and the binder resin,
The melt viscosity η ′ measured by an elevated flow tester is 10 ³ to 10 ⁵ poise at the 50% outflow point, and the natural logarithm lnη ′ of the melt viscosity is plotted against temperature. A heat-fixing capsule toner having a characteristic that the value is 1.0 ln (poise) / ° C. or less.