JPH0812457B2 - 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 widely used in which a recording material holding a toner image of the deposited toner 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) The heating roller is set to an optimum temperature in order to prevent fixing failure and transfer of toner to the heating roller, which is so-called offset development, due to the temperature of the heating roller fluctuating due to passage of a recording material or other external factors. 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, the 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 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 in which the high temperature body is not directly touched.

[Means and Actions for Solving the Problems] In Japanese Patent Application No. 62-147884 previously proposed by the present applicant, a heat-resistant sheet that moves by a heating element of low heat capacity that is energized and heated in a pulsed manner is used. An image forming apparatus having a short wait time and low power consumption has been proposed as a fixing device that heats a toner 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 the toner to a recording material by using a capsule toner in which core particles containing a binder resin and a coloring material as a main component are coated with the resin. The binder resin of the core particles comprises etherified bisphenols, aromatic dicarboxylic acids of 30 mole% or more in the total acid component, and alkenyl-substituted dicarboxylic acids of 5 to 40% by weight based on the total acid amount. And / or an alkali-substituted dicarboxylic acid and a divalent or higher polycarboxylic acid and / or a trivalent or higher polyol are co-condensed as a binder resin, and the polyester resin contains an elevated flow tester. when the melt viscosity eta 'is 10 ³ to 10 ⁵ poise at 50% pour point, yet the natural logarithm lnη the melt viscosity' was plotted against the temperature and by, the graph An encapsulating toner having a characteristic that the absolute value of the inclination is 1.0 ln (poise) / ° C or less is used. B) A fixedly supported heating body, and a recording material that is in pressure contact with the heating body and has a film interposed therebetween. A heat-fixing member that brings the toner into close contact with the heating member to heat and fix the visible image of the toner on the recording material,
The present invention relates to a heat fixing method, which comprises peeling a film from a toner fixing surface at a temperature higher by 30 ° C. or more than a maximum value of an endothermic peak measured by DSC of toner.

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 30 ° C or more higher than a maximum value of an endothermic peak measured by DSC, the toner mainly contains a binder resin and a coloring material. Which is a capsulated toner having core particles coated with a resin, wherein the binder resin of the core particles is etherified bisphenols, aromatic dicarboxylic acids of 30 mole% or more in total acid component, and total acid The amount of the alkenyl-substituted dicarboxylic acids and / or alkali-substituted dicarboxylic acids and the polycondensation of trivalent or higher valent polycarboxylic acids and / or polyols of the trivalent or higher valences relative to the amount of the polycondensation The polyester resin contains a reester resin as a binder resin, and the polyester resin has a melt viscosity η ′ measured by an elevated flow tester of 10 ³ to 10 ⁵ poise at an outflow point of 50%, and a natural logarithm (lnηη) of the melt viscosity. ′)
And a temperature, the absolute value of the slope of the graph is 1.0 ln (poise) / ° C. or less.

 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 polymer skeleton is composed of an etherified diphenol and an aromatic dicarboxylic acid as a basic skeleton and a polycarboxylic acid having a valence of 3 or more and / or a polyol having a valence of 3 or more. The toner is recorded with lower power consumption by using a capsule toner in which polyester resin in which alkenyl-substituted dicarboxylic acids and / or alkyl-substituted dicarboxylic acids are introduced as a soft segment in the polymer skeleton is used as a core binder resin It can be heat-fixed to a material.

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

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 manufacturing process of the core material 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.

Still another feature in the constitution of the heat fixing method of the present invention is that the melt viscosity η'of the above-mentioned specific polyester resin by the thermal elevated flow tester is 10 ³ to 1 at a flow point of 50%.
0 ⁵ poise, and when the natural logarithm lnη ′ of the melt viscosity in the temperature range is plotted against temperature, the absolute value of the slope of the graph is 1.0 ln (poise) / ° C or less, The toner can be fixed on the recording material with low 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) R: Extrusion pressure (dyne / cm ² ) [10kgf = 980 × 10 ⁴ dyn
e] B: Nozzle radius (cm) [0.1 cm] L: Nozzle length (cm) [0.1 cm] Plot of natural logarithm of 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 If the melt viscosity of the polyester, which is the core binder resin used for the toner in Example 1, at the 50% pouring point measured by an elevated flow tester exceeds 10 ⁵ poise, power consumption increases even in the heat fixing method of the present invention, and fixing Defects such as defects and difficulty in quick start appear. When the total amount of the reticulating components in the polyester of the present invention is 35% by weight or more, the melt viscosity may exceed 10 ⁵ poise.

Conversely, if the melt viscosity at the 50% outflow point is less than 10 ³ poise, defects due to excessive melting of the toner (set-off, blurring, etc.)
Becomes noticeable.

If the total amount of the reticulating components in the polyester of the present invention is less than 5% by weight, the melt viscosity may be less than 10 ³ poise. In addition, the absolute value of the slope of the natural logarithm lnη ′ of the melt viscosity η ′ at the 50% outflow point with respect to temperature reflects the sensitivity of the polyester resin of the present invention to temperature changes,
If the rate of change is 1.0 ln (poise) / ° C or more in absolute value, it tends to be offset to the film, and the gloss of the fixed image is too high and the image quality is degraded.

Further, the absolute value of this rate of change depends on the amount of the network component in the polyester resin in the present invention, the amount of the soft segment and the ratio thereof, and the fixability and the offset at the respective amounts used within the scope of the claims of the present invention. Property, image property and the like are satisfactorily achieved in the heat fixing method of the present invention.

Polyoxystyrene (6) -2.2-bis (4-hydroxy) can be used as the etherified diphenol which is a constituent raw material of the polyester resin as the core binder resin of the capsule toner applied to the present invention. Phenyl) propane, polyhydroxybutylene (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'-trichloro 4'-hydroxyphenylmethane, polyoxypropylene (3) -2-bromo-
4-hydroxyphenyl, 4-hydroxyphenyl ether, polyoxyethylene (2,5) -PP-bisphenol, polyoxybutylene (4) bis (4-hydroxyphenyl) ketone, polyoxystyrene (7) -bis ( 4-hydroxyphenyl) ether, polyoxypentylene (3) -2,2-bis (2.6-diaiod-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 those that are ethoxylated or propoxylated, having 2-3 moles of oxyethylene or oxypyropyrene per mole of bisphenol and having R as a propylene or sulfone group. 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
2-bis ((4-hydroxy, 2.6-dichlorophenyl) propane (the number of oxyalkylene units is 2.1 to 2.5 per mol of bisphenol).

Aromatic dicarboxylic acids which 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 and the like can be used, and other acids include maleic acid, fumaric acid, glital acid, cyclohexanecarboxylic acid, succinic acid, malonic acid, adipic acid, mesacon. Examples thereof include acids, citraconic acid, sebacic acid, and anhydrides of these acids.

Examples of the alkenyl-substituted dicarboxylic acid or alkyl-substituted dicarboxylic acid which 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. , Glutaric acid, sebacic acid, azelaic acid and their anhydrides, ester compounds and the like.

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.

Trivalent or higher polycarboxylic acids that are constituent raw materials of the polyester resin of the present invention include trimellitic acid, pyromellitic acid, cyclohexanetricarboxylic acids, and 2.5.
* 7-naphthalene tricarboxylic acid, 1.2 * 4-naphthalene tricarboxylic acid, 1.2 * 4-butane tricarboxylic acid, 1.2 * 5-hexane tricarboxylic acid, 1.3 dicarboxyl-2-methylene carboxylic propane, 1・
3-dicarboxyl-2-methyl-2-methylenecarboxylic propane, tetra (methylenecarboxylic) methane, 1,2,7,8-octanetetracarboxylic acid and their anhydrides, esterified products, etc. can be used, and trivalent or more Polyols of sorbitol, 1, 2, 3, 6-
Hexanthetol, 1.4 sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1.2.4-mesitatriol, glycerin, 2-methylpropanetriol, 2-methyl-
Examples include 1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene, erythro1,2,3-butanetriol, threo1,2,3-butanetriol. To be

In the core material particles used in the present invention, in addition to the polyester resin composed of the above-mentioned constituent materials, when the content is less than the content of the polyester resin and the melt viscosity η ′ by the elevated flow tester is 50% at the outflow point 10 ³ ~ 10 ⁵ Poise and the natural logarithm of its melt viscosity (lnη ')
Is plotted against temperature so that the absolute value of the slope of the graph does not exceed 1.0 ln (poise) / ° C or less, for example, 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, phenolic resin,
An aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc. may be contained.

Further, the core material particles used in the present invention may contain various release agents, if necessary. For example, polyfluorinated ethylene, fluororesin, fluorinated carbon oil, silicone oil, low molecular weight polyethylene, low molecular weight polypropylene and the like is 0.1 to 20% by weight, preferably 0.5 to 10% by weight relative to the core material particles.
It is used in the addition amount of weight%.

When the toner to be used is used as a magnetic toner containing magnetic fine particles, the magnetic fine particles may be magnetic or magnetizable materials such as iron and manganese.
There are metals such as nickel, cobalt and chromium, magnetite, hematite, various ferrites, manganese alloys, other ferromagnetic alloys, etc.
The amount of the magnetic fine particles contained in the magnetic toner that can be used as the fine powder of 5μ is 15 of the total weight of the magnetic toner.
~ 70 wt% (more preferably 25-45 wt% is good.

Further, various substances can be added to the toner used in the present invention for the purpose of controlling coloring and charge. For example, carbon black, iron black, graphite, nigrosine, metal complex of monoazo dye, ultramarine blue, phthalocyanine blue,
Examples include Hansa Yellow, Benzene Yellow, and various quinacridone lake pigments.

As a method of encapsulating these 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 No. 2 specification 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, styrene such as P-chlorostyrene, P-dimethylamino-styrene and the like, 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, N, N-dimethylaminoethyl methacrylate ester; , Half amide or diester imide, vinyl pyridine, N
-Nitrogen-containing vinyl such as vinylimidazole; vinylacetal such as vinylformal and vinylbutyral; vinyl monomers such as vinyl chloride, acrylotolyl, 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, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, melamine resin, polyether resin such as polyphenylene oxide or thioether resin, etc. Polymers, copolymers, and mixtures thereof can be used.

In some cases, the capsule toner of the present invention is used as a developer after mixing with 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, it is used as a developer after being mixed with an iron powder carrier, a ferrite carrier, or a carrier coated with a silicone resin, an allyl resin or the like.

 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 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 toilet 12. In addition,
After transferring the toner image, the residual toner on the drum 4 is cleaned.
Removed by 13.

FIG. 3 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 device, and as an example, an alumina substrate 21 having a thickness of 1.0 mm, a width of 10 mm, and a 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 the desired temperature and the amount of energy released controlled by the temperature measuring element 23. Approximate pulse width is 0.5 msec to 5 msec
Becomes 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 lower than T ₁ by about 10 to 30 ° C. 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
With less than film drive, drive roller 25 and driven roller
Driven by 26 and tension, it moves in the direction of the arrow without wrinkles.

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.

The endless belt has been described above, but as shown in FIG. 3 (b), a sheet feeding shaft 31 and a winding shaft 32 are used,
The fixing film may be an endless 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 heating rate of 10 ° C / min to 200 ° C for 10 minutes, and then rapidly cooling the toner to pretreat it in advance, then holding it again at 10 ° C for 10 minutes, then 10 ° C. / m
Measure up to 200 ℃ at a heating rate of in. In general,
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, structural examples of the polyester resin used in Examples and Comparative Examples of the present invention and production examples of capsule toner using the resin as a core binder resin will be described, but the present invention is not limited thereto. Not a thing. The number of parts means parts by weight.

(Production Example of Polyester Resin a) A total of 1500 g 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. Next, the flask was placed in a mantle heater, and nitrogen gas was introduced from a glass inlet tube to keep the inside of the reactor under an inert atmosphere and heated. Thereafter, 0.10 g of dibutyltin oxide was added and the temperature was kept at 210 ° C. to carry out a cocondensation reaction for 12 hours to obtain a polyester resin a.

The apparent viscosity η'at 50% outflow point of this polyester resin a by the elevated flow tester shown in Fig. 1 is 1.6.
× 10 ⁴ Poise, and the absolute value of the slope of the natural logarithm lnη ′ of viscosity η ′ with respect to temperature within this temperature range is 0.098 ±
It was 0.01 ln (poise) / ° C.

(Sample A) 100 parts of polyester resin a and 60 parts of magnetic powder (magnetic iron oxide) according to the above-mentioned production example are melt-kneaded by a twin-screw kneading extruder, cooled, crushed by an airflow crusher, and classified by an air classifier. Then, core material particles having an average particle diameter of 12 μm 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.

For 100 parts of this capsule toner, colloidal silk
0.5 part was externally mixed and used as sample A.

(Production Example of Polyester Resin b) A polyester resin b was obtained in the same manner as the polyester resin a except that the above constituent materials were used. The apparent viscosity η'at the 50% outflow point of this polyester resin by the elevated flow tester shown in FIG. 1 is 6.0 × 10 ³ poise, and the slope of the viscosity η'in this temperature range with respect to the natural logarithm lnη ' The absolute value was 0.17 ± 0.01 ln (poise) / ° C.

(Sample B) A sample B was obtained in the same manner as the sample A except that 100 parts of the above polyester resin b was used instead of the polyester resin a.

(Sample C) The above components were treated in the same manner as in Sample A, and the average diameter was 10.6 μm.
Core particles were obtained.

 The above core 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 gelatin grains having a film thickness of 0.8 μm. Next, this dispersion was filtered, 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
Sample C by externally mixing 0.6 parts of colloidal silica
I got

110 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 body 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 nip 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, and as the heat-resistant sheet, a polyimide film having a thickness of 20 μm having a low-resistance release layer in which a conductive substance 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-150Z (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 machine 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 fixing property was as good as 2 to 5% (average 3.3%) 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. Furthermore, when the film of the fixing device and the surface of the facing roller were observed after continuous paper passage, almost no adhesion of toner was found.

Furthermore, when 10 g of this toner was placed in a polypropylene cc 100 cc cup in an oven with a tank temperature of 45 ° C. (constant) and left for 1 day, and the blocking property was observed, no toner soul was found. ,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 a power consumption of 150 w was attached to the center of the heat roller and the temperature was raised while the roll was rotating, the surface temperature rose to 150 ° C. even after 4 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 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 4 to 7% (average 5.5%) at the initial stage and after 200 sheets, and when 200 sheets were passed, the image on the image due to the offset phenomenon was already present. It was observed that the transfer paper was missing, and the back side of the transfer paper was smeared at 4,500 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

[Advantages of the Invention] As described above, according to the heat fixing method of the present invention, an image having good fixability can be obtained with less power consumption, no offset.

[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 59-68766 (JP, A) JP 59-157678 (JP, A) JP 61-278861 (JP, A) JP 61-284772 (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 core particles mainly composed of a binder resin and a coloring material are coated with a resin, wherein a) the binding of the core particles The resin is (a) etherified bisphenols, (b) 30 mol% or more of aromatic dicarboxylic acids in the total acid component, and (c) 5 to 40% by weight of alkenyl-substituted dicarboxylic acids based on the total acid amount. And / or an alkyl-substituted dicarboxylic acid and (d) a polyester resin obtained by co-condensing a polycarboxylic acid having a valence of 3 or more and / or a polyol having a valence of 3 or more are contained as a binder resin, and the polyester resin is elevated. The melt viscosity η'at the 50% outflow point by the equation flow tester is 10 ³ to 10 ⁵ poise, and the slope of the graph is plotted when plotted against the natural logarithm lnη'of the melt viscosity and the temperature. Using an encapsulating toner having an absolute value of 1.0 ln (poise) / ° C. or less, and b) a fixedly supported heating body, and a recording material that is in pressure contact with the heating body and has a film interposed therebetween. A heat-fixing member that brings the toner into close contact with the heating member to heat and fix the visible image of the toner on the recording material,
A heat fixing method, which comprises peeling a film from a toner fixing surface at a temperature of 30 ° C. or more higher than a maximum value of an endothermic peak measured by a toner DSC. 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. 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 coloring material. A capsule toner having core particles as a main component coated with a resin, wherein the binder resin of the core particles comprises (a) etherified bisphenols and (b) 30 mole% or more of aromatic dicarboxylic acid in all acid components. (C) 5-40% by weight of alkenyl-substituted dicarboxylic acids and / or alkyl-substituted dicarboxylic acids with respect to the total amount of acids, and (d) trivalent or higher polycarboxylic acids and / or trivalent or higher polycarboxylic acids. Containing the class co condensed polyester resin as a binder resin, and the polyester resin is the melt viscosity due to elevated type flow tester eta 'is 10 ³ to 10 ⁵ poise at 50% pour point, yet the molten Natural logarithm of viscosity (lnη ′)
And a temperature plotted against temperature, the absolute value of the slope of the graph is 1.0 ln (poise) / ° C. or less.