JPH0816804B2 - Heat fixing method and heat fixing toner used in the method - Google Patents

Description

The present invention relates to a heat fixing method for fixing a visible image formed by toner in electrophotography, electrostatic printing, magnetic recording and the like to a recording material, and a heat fixing method. Toner for heat fixing used [Prior art] Conventionally, as a method of fixing a visible image of the toner on a recording material, a heating roller maintained at a predetermined temperature and an elastic layer having a pressure contact with the heating roller. A heat roll fixing method is often used in which a recording material holding an unfixed toner image is heated while being nipped and conveyed by a pressure roller.

Further, a belt fixing method described in US Pat. No. 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, (1) a so-called wait time for which the image forming operation is prohibited until the heat roller reaches a predetermined temperature is required.

(2) Maintaining the heating roller at an optimum temperature in order to prevent improper fixing and transfer of toner to the heating roller, or so-called offset phenomenon, due to fluctuations in the temperature of the heating roller due to passage of recording material or other external factors. Therefore, it is necessary to increase the heat capacity of the heating roller or the heating body for this purpose, which requires a large amount of electric power.

(3) Since the roller has a constant 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 toner has a high adhesiveness. In combination with the curvature of, the paper may be jammed due to the offset or the 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.

Further, in the belt fixing method described in U.S. Pat. No. 3,578,797, the above-mentioned problem of heat roll quantification (1),
(2) has not been fundamentally solved.

Further, in Japanese Patent Application No. 62-147884 previously proposed by the applicant, a toner image is heated through a heat resistant sheet which is moved by a heating element of a low heat capacity which is energized and heated in a pulsed manner to record a recording material. There has been proposed an image forming apparatus which has a short wait time and low power consumption by a fixing device for fixing to.
Similarly, Japanese Patent Application No. 63-12069 previously proposed by the applicant.
In a fixing device for heating and fixing a visible image of a toner onto a recording material via a 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 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-described fixing device, It depends largely on the characteristics of the toner.

That is, an object of the present invention is to provide a toner for a recording material, which has substantially no wait time for solving the above-mentioned problems, or has an extremely short time, and has low power consumption and does not cause an offset phenomenon. An object of the present invention is to provide a heat-fixing method in which an image can be fixed well and a heat-fixing toner used in the method.

Another object of the present invention is to provide a heat-fixing method that does not require a heat-resistant special bearing and a heat-fixing toner used in the method by using no high-temperature rotating roller.

Further, the present invention provides a heat fixing method which is excellent in safety or does not require a protective member, and a heat fixing toner used in the method, which has a fixing device configuration in which the high temperature body is not directly touched. It is in.

[Means and Actions for Solving the Problems] The present invention relates to a heat fixing method for heating and fixing a visible image of a toner onto a recording medium, comprising: a) etherified bisphenols, divalent or higher carboxylic acids, their anhydrides, and A toner containing a polyester resin co-condensed with a carboxylic acid selected from the group consisting of the lower alkyl ester and a release agent, the toner comprising: (i) a thermal overhead flow tester of the polyester resin; The melt viscosity η'is 10 ³ to 10 ⁶ P (poise) at any temperature in the temperature range of 80 ° C to 120 ° C,
When the natural logarithm (lnη ′) of the melt viscosity at 0 ℃ was plotted against temperature, the absolute value of the slope of the graph was 0.50ln
An aromatic vinyl monomer and an unsaturated fatty acid or unsaturated, which has a physical property of (poise) / ° C. or less, and (ii) the release agent has a melt viscosity of 1 to 250 cp (centipoise) at 160 ° C. Polyolefin graft-modified with fatty acid ester, 0.1 to 2 relative to the total amount of binder resin
0% by weight of the toner is used, and b) a fixed and supported heating element, and a pressure member that is in pressure contact with the heating element and presses the recording element to the heating element through a fixing film. The visible image of the toner is heat-fixed on the recording medium, and c) the fixing film is peeled from the fixing surface of the toner at a temperature higher than the maximum value of the endothermic peak of the toner measured by DSC. And a heat fixing method.

Further, according to the present invention, a visible image of toner is formed on the recording body by a fixedly supported heating body and a pressing member which is in pressure contact with the heating body and brings the recording body into close contact with the heating body via a fixing film. In the toner used in the heat fixing method in which the fixing film is peeled from the fixing surface of the toner at a temperature higher than the maximum value of the endothermic peak of the toner measured by DSC, the toner is ether. Bisphenols and carboxylic acids selected from the group consisting of divalent or higher carboxylic acids, their anhydrides and their lower alkyl esters,
A toner containing a copolycondensation-polymerized polyester resin and a release material, wherein the melt viscosity η'of the polyester resin measured by a hot overhead flow tester is at any temperature in the temperature range of 80 ° C to 120 ° C. Is 10 ³ to 10 ⁶ P (poise), and when the natural logarithm (lnη ′) of the melt viscosity at 80 ℃ and 120 ℃ is plotted against temperature, the absolute value of the slope of the graph is 0.50ln (poise). ) / ° C. or lower, and
(Ii) the release agent is an aromatic vinyl monomer having a melt viscosity of 1 to 250 cp (centipoise) at 160 ° C. and a polyolefin graft-modified with an unsaturated fatty acid or an unsaturated fatty acid ester, The present invention relates to a heat-fixing toner containing 0.1 to 20% by weight based on the amount of resin.

By using the above means, it is possible to heat and fix the toner on the recording material with extremely low power consumption and without offsetting to the film. Hereinafter, the present invention will be described in detail.

For the viscosity measurement according to the present invention, an elevated flow tester (Shimadzu flow tester CFT-500 type) shown in FIG. 1 is used,
First, 1.5 g of the sample 3 molded by using a pressure molding machine is applied with a load of 10 kgf by the plunger 1 at a constant temperature and the diameter φ1.
mm, 1 mm long nozzle 4 so that it can be pushed out, so that the plunger drop of the flow tester (outflow speed)
Was measured. This outflow rate was measured at each temperature (80 ° C to 120 ° C temperature range at 5 ° C intervals), and from this value the apparent viscosity η '
Can be calculated by the following equation.

However, η ′: Apparent viscosity (poise) TW ′: Apparent shear reaction of pipe wall (dyne / cm ² ) DW ′: Apparent shear velocity of pipe wall (l / sec) Q: Outflow velocity (cm ³ / sec = ml / sec) P: Extrusion pressure (dyne / cm ² ) [10 kgf = 980 × 10 ⁴ dyne] R: Nozzle radius (cm) L: Nozzle length (cm) Binder resin used in the toner of the present invention If the melt viscosity of the polyester at 80 ° C. to 120 ° C. exceeds 10 ⁶ poise, power consumption increases even in the heat fixing method of the present invention, and quick start becomes difficult.

On the other hand, if the melt viscosity at 80 ° C to 120 ° C is less than 10 ³ poise, defects such as penetration into the transfer paper due to excessive melting of toner, set-off and image bleeding due to spread of melted toner are noticeable. Become.

Further, the absolute value of the slope of the natural logarithm lnη ′ of the melt viscosity in the temperature range of 80 ° C. to 120 ° C. reflects the sensitivity of the polyester resin of the present invention to the temperature change, and 0.50 ln (poise) / ° C. If it exceeds the limit, the film is likely to be offset.

Further, as the alcohol component which is a constituent raw material of the polyester resin according to the present invention, etherified bisphenols are preferable, whereby the impact resistance as a toner,
Abrasion resistance is maintained, and electrophotographic characteristics other than fixability are not adversely affected.

In the present invention, the “slope” of the viscosity is, as shown in FIG. 2, connected by a straight line between the measurement point at t _a ° C and the measurement point at t _b ° C in the graph, Is a value obtained by calculating the “inclination” according to, and this is approximated and used as the “inclination” of the slope. (However, ln
eta _{a 'denotes} a value obtained by taking the natural logarithm of the viscosity at t _a ℃, lnη _b' indicates the value at t _b ° C.. ) As the etherified diphenol which is a constituent raw material of the polyester resin as the binder resin of the toner applied to the present invention, polyoxystyrene (6) -2 can be used.
-2-bis (4-hydroxyphenyl) 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'-hydroxyphenyl methane, 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-diaiodo-4-hydroxyphenyl) propane and polyoxypropylene (2.2)
It is 2,2-bis (4-hydroxyphenyl) propane.

One group of etherified diphenols are etherified bisphenols. A preferred group of etherified bisphenols are ethoxylated or propoxylated,
It has 2 to 3 moles of oxyethylene or oxypropylene per mole of bisphenol, and has 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
And 2-bis (4-hydroxy, 2.6-dichlorophenyl) propane (the number of oxyalkylene units is 2.1 to 2.5 per mol of bisphenol).

As the divalent or higher carboxylic acids that are the constituent raw materials of the polyester resin according to the present invention, any of aromatic carboxylic acids and other carboxylic acids can be used, and 95 mol% or more of the acid components are dicarboxylic acids. And is preferably 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, bezophenone-4,4'-dicarboxylic acid, 1.2-
Aromatic dicarboxylic acids such as diphenyloxyethane-p.p'-dicarboxylic acid can be used, and other acids include:
Use of maleic acid, fumaric acid, glital acid, cyclohexanecarboxylic acid, succinic acid, malonic acid, adipic acid, mesaconic acid, citraconic acid, sebacic acid and anhydrides of these acids and lower alkyl ester products of these acids. You can

Also, tricarboxylic or higher polycarboxylic acids can be used in a small amount, and examples thereof include trimellitic acid, pyromellitic acid, cyclohexanetricarboxylic acids, 2.5 / 7-naphthalenetricarboxylic acid, and 1.2-4-naphthalenetricarboxylic acid. Acid, 1,2-, 4-butanetricarboxylic 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, their anhydrides, and their lower alkyl ester compounds may be used in a small amount, and trivalent or higher valent polyols may be used in a small amount. 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, erythro-1,2.3-butanetriol , Threo-1,2,3-butanetriol, and the like.

One of the structural features of the heat fixing toner of the present invention is that it contains a releasable component (release agent),
The releasable component is a polyolefin graft-modified with an aromatic vinyl monomer and an unsaturated fatty acid or an unsaturated fatty acid ester, and the releasable component is 16
The melt viscosity at 0 ° C. is in the range of 1 to 250 cp (centipoise), and the content is 0.1 to 20% by weight based on the total amount of the binder resin.

The polyolefin is a homopolymer of α-olefin such as ethylene, propylene, 1-butene, 1-hexene, 1-decene, 4-methyl-1-pentene or a copolymer of two or more α-olefins. . Furthermore, polyolefin oxides are also included.

The unsaturated fatty acid ester used for synthesizing the graft-modified polyolefin includes methacrylic acid and methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, lauryl. Methacrylate, stearyl methacrylate, dothesyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, 2-hydroxyethyl methacrylate, 2,2,2
-Methacrylates such as trifluoroethyl methacrylate and glycidyl methacrylate, acrylic acid and methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-octyl acrylate, lauryl acrylate, stearyl acrylate, dodecyl acrylate, 2 -Ethylhexyl acrylate, phenyl acrylate, 2-chloroethyl acrylate, acrylic acid-
2-hydroxyethyl, cyclohexyl acrylate,
Acrylates such as dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dibutylaminoethyl acrylate, 2ethoxy acrylate, 1,4-butanediol diacrylate, maleic acid, fumaric acid, itaconic acid, citraconic acid and monoethyl maleate, Diethyl malate, monopropyl maleate, dipropyl maleate, monobutyl maleate, dibutyl maleate, di-2 ethylhexyl malate, monoethyl fumarate, diethyl fumarate, dibutyl fumarate, di-2 ethylhexyl fumarate, Examples thereof include unsaturated dibasic acid esters such as monoethyl itaconate, diethyl itaconate, monoethyl citraconic acid, and diethyl citraconic acid, and one or two of these may be used at the same time. .

As the aromatic vinyl monomer, styrene, o
-Methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, 2,4 dimethylstyrene,
p-ethylstyrene, pn-butylstyrene, p-te
rt-butyl styrene, pn-dodecyl styrene, p-
Phenyl styrene, p-chlorostyrene, etc. can be mentioned, and these 1 type (s) or 2 or more types can be used simultaneously.

As a method of graft modification, a conventionally known method can be used. For example, the polyolefin, the aromatic vinyl monomer, and the unsaturated fatty acid or unsaturated fatty acid ester are heated in a molten state, a solution state, or a molten state in the atmosphere, under pressure as necessary in the presence of a radical initiator. By carrying out the reaction, a graft-modified polyolefin is obtained. The grafting with the aromatic vinyl monomer and the unsaturated fatty acid or the unsaturated fatty acid ester may be carried out both at the same time or individually.

Examples of the initiator used in the grafting reaction include benzoyl peroxide, cyclolbenzoyl peroxide, di-tert-butyl peroxide, lauroyl peroxide, tert-butyl perphenyl acetate, cumin perpivalate, and azobis-isobutyrate. Ronitrile, dimethylazoisobutyrate, dicumyl peroxide, etc. can be mentioned.

The proportion of the grafting agent with respect to the polyolefin is preferably 0.1 to 100 parts by weight, more preferably 1 to 50 parts by weight, based on 100 parts by weight of the polyolefin. If it is less than 0.1 part by weight, the effect of grafting is hardly exerted, and if it exceeds 100 parts by weight, the advantageous properties originally possessed by the polyolefin are lost.

The weight ratio of the aromatic vinyl monomer and the unsaturated fatty acid or unsaturated fatty acid ester is preferably 95: 5 to 5:95, more preferably 80:20 to 20:80. When the amount of unsaturated fatty acid or unsaturated fatty acid ester is large, the releasing effect of the polyolefin tends to decrease, and when the amount of aromatic vinyl monomer is large, the dispersibility of the polyolefin in the toner is not improved so much.

The addition amount of the graft-modified polyolefin used in the present invention is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the binder resin.
If the amount is less than 0.1 part by weight, a sufficient releasing effect cannot be exhibited, and if the amount is more than 20 parts by weight, the toner blocking property tends to be lowered.

The graft-modified polyolefin used in the present invention preferably has a melt viscosity at 160 ° C. in the range of 1 to 250 cp (centipoise). If it is less than 1 cp, toner blocking is likely to occur and 250 cp
If it exceeds the range, the modified polyolefin is less likely to seep out of the toner and the releasing effect is difficult to be exhibited. In the fixing method of the present invention, it is generally preferable to use a releasable component having a low melt viscosity when the fixing temperature is low.

The melt viscosity as referred to in the present invention uses the value measured by a B-type rotational viscometer.

Furthermore, in the toner used in the present invention, in addition to the polyester resin composed of the above-mentioned constituent materials, the melt viscosity η'by an elevated flow tester is 80% to 120% at a ratio of 30% by weight or less of the polyester resin. Do not deviate from 10 ³ to 10 ⁶ poise at any temperature in the temperature range of ° C, and 80
When the natural logarithm (lnη ′) of the melt viscosity at ℃ and 120 ℃ is plotted against temperature, the absolute value of the slope of the graph is 0.50.
In order not to exceed ln (poise) / ° C., for example, vinyl resin mainly containing 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.

When the toner to be used is used as a magnetic toner containing magnetic fine particles, the magnetic fine particles may be any material exhibiting magnetism or magnetizability, for example, metals such as iron, manganese, nickel, cobalt and chromium, magnetite. , Hematite, various ferrites, manganese alloys, other ferromagnetic alloys, etc., and have an average particle size of about 0.05 to 5
What was made into a fine powder of μm can be used. The amount of magnetic fine particles contained in the magnetic toner is 15 to 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, black iron, graphite, nigrosine,
Examples thereof include metal complexes of monoazo dyes, ultramarine blue, phthalocyanine blue, Hansa yellow, benzine yellow and various quinacridone lake pigments.

Alternatively, colloidal silica or the like as a fluidity improver may be contained in the toner in an amount of 10 to 40% by weight. Of course,
The fluidity improver may be mixed with the outside of the toner and used, and the addition amount at that time is 0.2 to 5% by weight (based on the weight of the toner).

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, the maximum value of the endothermic peak that appears first is from 40 ° C to 120 ° 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, it is preferable that the temperature T ₃ is peeled from the toner fixing surface of the fixing film 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 to 150 (° C.) It is preferable to peel under high conditions.

Since the binder resin of the toner is a polyester resin having a specific melt viscosity characteristic, it consumes less power during fixing, and quick start is possible. Further, the polyester resin of a specific graft-modified polyolefin used as a release agent is used. With good dispersibility and excellent releasability, the fixing film is peeled from the toner fixing surface in a state where the excellent releasability is sufficiently exhibited. The surface is easily peeled off. Further, when the surface temperature T ₃ of the fixing film is lower than the heat absorption temperature T _D of the toner, it becomes difficult to smoothly peel the fixing film from the toner fixing surface, so that the surface state of the toner fixing surface is uneven. In addition, the adhesion between the surface of the fixing film and the toner fixing surface is increased, and defective separation of the recording material from the fixing film is likely to occur.

The maximum value of the endothermic peak in the present invention is calculated according to ASTM D-3418-82. In particular,
Pre-treat the toner in advance by collecting 10 to 5 mg of toner and heating it from room temperature to 200 ° C under nitrogen atmosphere at a heating rate of 10 ° C / min, holding it at 200 ° C for 10 minutes, and then rapidly cooling it. After that, hold again at 10 ° C for 10 minutes, and heat up to 200 ° C at a temperature rising rate of 10 ° C / min to measure. Generally, the data shown in FIG. 3 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.

In the present invention, the heating element has a smaller heat capacity than the conventional heat roll and has a linear heating portion, and the maximum temperature of the heating portion is preferably 100 to 300 ° C.

Also, the film located between the heating element and the pressure member,
It is preferable that the heat-resistant sheet has a thickness of 1 to 10 μm. As these heat-resistant sheets, polyester, PET (polyethylene terephthalate), PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) having high heat resistance, In addition to polymer sheets of PTFE (polytetrafluoroethylene), polyimide, polyamide, etc., metal sheets of aluminum etc. and laminate sheets composed of metal sheets and polymer sheets are used.

A more preferable film structure is that these heat resistant sheets have a release layer and / or a low resistance layer.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited thereto.

FIG. 4A shows a structural diagram of the fixing device of this embodiment.

Reference numeral 11 denotes a low-heat-capacity linear heating element that is fixedly supported by the apparatus, and as an example, a resistance material 13 is applied to an alumina substrate 12 having a thickness of 1.0 mm, a width of 10 mm, and a longitudinal length of 240 mm to have a width of 1.0 mm. Power is supplied from both ends in the direction. Energization is DC 100V cycle 20msec
A pulse corresponding to a desired temperature and the amount of energy released controlled by the temperature measuring element 14 with a pulse-like waveform is given by changing its pulse width. Approximate pulse width is 0.5 msec to 5
It becomes msec. The fixing film 15 moves in the direction of the arrow in the drawing by coming into contact with the heating body 11 whose energy and temperature are controlled in this way. An example of this fixing film is a heat-resistant film having a thickness of 20 μm, such as polyimide, polyetherimide, PE
It is an endless film obtained by coating S, PFA with a release layer of 10 μm on at least the image contact surface side, which is obtained by adding a conductive material to a fluororesin such as PTFE or PFA. Generally, the total thickness is 100 μm, more preferably less than 40 μm, and the film drive is a variable roller.
Driven by 16 and driven roller 17 and tension, it moves in the direction of the arrow without wrinkles.

Reference numeral 18 denotes a pressure roller having a rubber elastic layer having a good releasability such as silicone 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 20 on the transfer material 19 is guided to the fixing portion by the entrance guide 21, and the fixed image is obtained by the above-mentioned heating.

The endless belt has been described above, but as shown in FIG. 4 (b), the sheet feeding shaft 24 and the winding shaft 27 may be used, and the fixing film may be an end film.

The image forming apparatus is applicable to all fixing devices such as copying machines, printers, fax machines, etc. that form an image using toner.

When the temperature detected by the temperature measuring element 14 in the low heat capacity linear heating element 11 is T ₁ , the surface temperature T ₂ of the film 15 facing the resistance material 13 is substantially equal to T ₁ . In addition, the film surface temperature T _{3 at} the portion where the film 15 peels from the toner fixing surface
Is a temperature substantially equal to the temperatures T ₁ and T ₂ .

[Examples] Hereinafter, production examples of the polyester resin used in Examples and Comparative Examples of the present invention and production examples of toners using the resin as a binder resin will be described, but the present invention is not limited thereto. . Table 1 below shows examples of the graft-modified polyolefin used in the examples of the present invention.

Example 1 A total of 1500 g of the above constituent raw materials was placed in a 2-volume four-necked round bottom flask equipped with a thermometer, a stainless steel stirrer, a glass nitrogen introduction tube, and a flow-down condenser. Then, the flask was placed in a mantle heater, and nitrogen gas was introduced through a glass introduction tube to maintain the inside of the reactor in an inert atmosphere and raise the temperature. Thereafter, 0.10 g of dibutyltin oxide was added, and the mixture was co-condensed at 210 ° C. for 12 hours to obtain a polyester resin A.

Apparent viscosity eta _{a 'and} t _b at t _a = 80 ° C. by elevated type flow tester shown in FIG. 1 of the polyester resin A
= Apparent viscosity η _b ′ at 120 ℃ is 7.9 × 10 ⁵ poi
se, 8.5 × 10 ² poise, and the absolute value of the slope of the natural logarithm lnη ′ of this melt viscosity with respect to temperature is 0.17 ln (pois
e) / ° C.

100 parts by weight of the polyester resin A, 6 parts by weight of copper phthalocyanine pigment, 2 parts by weight of a negative charge control agent, and graft-modified polyolefin (No. 1 in Table 1) are melt-kneaded by a twin-screw kneading extruder, then cooled, and then air flow type It was crushed by a crusher and classified by an air classifier to obtain a blue fine powder having an average particle size of 12.5 μm. Toner 100 was obtained by adding 0.5 part by weight of hydrophobic silica powder to 100 parts by weight of this blue fine powder and mixing. Further, the T _{D of} this toner A was 56 ° C. Next, 100 parts by weight of a coating ferrite carrier (coating agent is a fluorine-acryl-styrene copolymer) was mixed with 8 parts by weight of this toner A to obtain a developer A.

In the heat fixing device of the present invention shown in FIG. 4 (a), the temperature detecting element surface temperature T ₁ of the heating body 11 is 110 ° C., the power consumption of the resistance material of the heating portion is 150 W, and the space between the heating body 11 and the pressure roller 18 is The total pressure was set to 5 kg, the nip between the pressure roller and the film was set to 3 mm, and the rotation speed of the fixing film 15 was set to 50 mm / sec.

As the heat-resistant sheet, a 20 μm-thick polyimide film having a low-resistance release layer in which a conductive material is dispersed in PTFE is used on the contact surface with the recording material. At this time, it took about 1 time until the temperature T _{1 of the} temperature sensing element of the heating element reached 110 ° C.
It was seconds. Furthermore, the temperature T ₂ is 108 ° C. and the temperature T ₃ is 1
It was 07 ° C.

As a method of evaluation, a commercially available copying machine NP-6650 manufactured by Canon, which was modified to remove the fixing device, was used, and the developer A was put in the color developing device for image formation to obtain an unfixed image of the toner A. As the recording material, 54 g / m ² of commercially available copier paper Canon New Dry Paper (Canon Sales Company) was used.
The unfixed image of the obtained toner A was obtained as a fixed image by the above fixing device.

In the fixing test of the fixed image, 200 unfixed images are continuously fed to obtain a fixed image, and the 1,10,50,100,200th sheet is rubbed with a symbol paper with a load of 50 g / cm ² before and after rubbing. The image density reduction rate (%) was expressed. In the offset resistance test, an unfixed image having a solid black color was continuously fixed, and the number of fixings was used to evaluate how the fixed image or the fixing film was stained.

As a result, the fixability was almost constant at the beginning of the 200th sheet and at the 200th sheet and was as good as 0 to 1%. As for the offset resistance, almost no toner adhesion was observed on the surfaces of the fixing film 15 and the pressure roller 18 even after passing 10,000 sheets. Further, the obtained image was good without bleeding or set-off.

Comparative Example 1 In place of the release agent (graft-modified polyolefin, No1) of Toner A shown in Example 1, non-graft-modified polyethylene (η ′ = 10 cp, at 160 ° C.) was used.
A toner was manufactured in the same manner as in Example 1 and evaluated in the same manner as in Example 1. As a result, the fixability is as early as 200 sheets and 2
It was 2 to 5% at the 00th sheet. Further, after passing 10,000 sheets, the toner hardly adhered to the surface of the fixing film 15 and the pressure roller 18, but after passing 20,000 sheets, a slight offset was observed on the fixing film 15.

Example 2 Same as Example 1 except that a graft-modified polyolefin (No. 8 in Table 1, No. 8) was used as a release agent instead of the release agent (graft-modified polyolefin, No1) of Toner A shown in Example 1. The toner B manufactured as described above was evaluated in the same manner as in Example 1. As a result, the fixability is as early as 200 sheets and 2
It was almost constant even on the 00th sheet and was as good as 0 to 1%. Regarding the offset resistance, adhesion of toner to the surface of the fixing film 15 and the pressure roller 18 was not observed even with 20,000 sheets of passing paper. Further, the obtained image was good without bleeding or set-off.

Example 3 A polyester resin B was obtained in the same manner as the polyester resin A described in Example 1 except that the above constituent materials were used.
The apparent viscosity at t _a = 80 ° C. by elevated type flow tester shown in Figure 1 of the polyester resin B eta _{a 'and} t _b =
The apparent viscosity n _b ′ at 120 ℃ is 4.0 × 10 ⁵ poise,
2.2 × 10 ² poise, and the natural logarithm of this melt viscosity l
The absolute value of the slope of nη 'with respect to temperature is 0.19ln (poise) /
° C.

Polyester resin B was used instead of polyester resin A, and graft-modified polyolefin was used as a release agent in Table 1.
Toner C was obtained in the same manner as in Example 1 except that No. 9 was used instead of No. 1. The T _D of Toner C was 55 ° C.

The temperature measuring element surface temperature T ₁ of the heating element 11 in Example 1 15
A fixing test and an offset resistance test were performed in the same manner as in Example 1 except that the rotation speed of the fixing film was set to 0 mm and the rotation speed of the fixing film was 150 mm / sec. Even 20,000 sheets were good.

Further, the wait time of the fixing device was about 1 second, which was the same as in Example 1. At this time, the temperature T ₂ was 148 ° C and the temperature T ₃ was 146 ° C.

Further, the obtained image was good without bleeding or set-off.

Comparative Example 2 The following test was attempted in order to compare the present heat fixing device with a conventional heat roll fixing device. An external fixing device for heat roll fixing was prepared. The hot roll 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 in the center thereof, and silicon is used for the lower roller.
Furthermore, the nip width is 3 mm. The total pressure between the rollers was 7 kg.

A heater with a power consumption of 150 W was attached to the center of the heat roll, and when the temperature was raised while the roll was rotating, the surface temperature was 150 ° C.
It took as long as 4 minutes to reach. Moreover, in this state, when the paper was passed at a paper feeding speed of 150 mm / s, the surface temperature dropped sharply after 3 to 5 sheets were continuously fed, and it became impossible to adjust the temperature.

Therefore, when the heater was changed to 700W, the time for the roller surface temperature to reach 150 ° C was 48 seconds, and although it took some time to adjust the temperature even if the paper was continuously fed, the roller surface temperature remained steady. Could be maintained.

With this setting, an unfixed image of toner C similar to that in Example 3 was used to perform a fixing test at a fixing processing speed of 150 mm / s.

As a result, the fixability is the same as in Example 3, and the density decrease rate is 2 to 2.
Although it was as good as 4%, some contamination due to offset of toner began to be observed on the surface of the fixing roller after 3,000 sheets were passed, and the contamination was transferred to the lower roller when 8,000 sheets were passed.

Example 4 The above was melt-kneaded by a twin-screw kneading extruder, cooled, crushed by an airflow crusher, and classified by an air classifier to obtain a black fine powder having an average particle size of 12.0 μm. Toner 100 was obtained by adding 0.4 parts by weight of hydrophobic silica powder to 100 parts by weight of this black fine powder and mixing. The T _D of Toner D was 57 ° C.

Using a modified machine obtained by removing the fixing device of the commercially available Canon copier NP-6650, the toner D was put in a black developing device and an image was formed to obtain an unfixed image of the toner D. When the following evaluation is performed under the same conditions as in Example 3, the fixability is 2
It was as good as ~ 4%, and the offset resistance was good up to the 20,000th sheet.

[Effects of the Invention] As described above, according to the heat fixing method of the present invention and the heat fixing toner used in the method, the toner image is fixed well on the recording material, and the toner for the fixing film is fixed. There is no offset phenomenon, there is no penetration of toner into the recording material, there is no set-off, and a sharp image without bleeding is obtained,
Moreover, the power consumption is low and the wait time is extremely short.

[Brief description of drawings]

FIG. 1 shows a schematic sectional view of an elevated flow tester for measuring the melt viscosity of a toner or a binder resin. FIG. 2 is a diagram showing a graph relating to the slope of the natural logarithm of the viscosity of the toner or the binder resin with respect to temperature. FIG. 3 is a graph showing the endothermic peak of the toner. FIG. 4 (a) is a schematic cross-sectional view of a fixing device for carrying out the fixing method of the present invention, and FIG. 4 (b) is for carrying out the fixing method of another embodiment of the present invention. FIG. 3 shows a schematic sectional view of a fixing device. 1 …… Piston (plunger) 2 …… Cylinder 3 …… Sample 4 …… Die (nozzle) 5 …… Die (nozzle) retainer 11 …… Heating body 12 …… Alumina substrate 13 …… Resistance material 14 …… Temperature Element 15 …… Fixing film 16 …… Drive roller 17 …… Following roller 18 …… Pressing roller 19 …… Recording material 20 …… Unfixed toner 21 …… Inlet guide 24 …… Sheet feeding shaft 27 …… Sheet winding axis

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Satoshi Matsunaga 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yasuhide Goseki 3-30-2 Shimomaruko, Ota-ku, Tokyo Kya Non-Incorporated (72) Inventor Kasuya Valuable 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masuo Yamazaki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-60-254151 (JP, A) JP-A-61-84657 (JP, A) JP-A-63-75755 (JP, A) JP-A-63-128363 (JP, A) Open Sho 58-100139 (JP, A)

Claims (4)

[Claims] 1. A heat-fixing method for heat-fixing a visible image of a toner on a recording medium, which is selected from the group consisting of a) etherified bisphenols, divalent or higher carboxylic acids, their anhydrides and their lower alkyl esters. A toner containing a polyester resin and a release agent that are copolycondensed with a carboxylic acid to be produced, wherein (i) the melt viscosity η'of the polyester resin measured by a thermal overhead flow tester is 80 ° C to 120 ° C. 10 ³ to 10 ⁶ P (poise) at any temperature in the temperature range of 80 ° C, 12
When the natural logarithm (lnη ′) of the melt viscosity at 0 ℃ was plotted against temperature, the absolute value of the slope of the graph was 0.50ln (po
ise) / ° C. or less, and (ii) the release agent has a melt viscosity of 1 to 250 cp (centipoise) at 160 ° C. and an aromatic vinyl monomer and an unsaturated resin acid or unsaturated resin acid. A toner, which is a polyolefin graft-modified with a saturated fatty acid ester and is contained in an amount of 0.1 to 20% by weight based on the total amount of the binder resin, is used. And a heat-fixing member for bringing the recording material into close contact with the heating element via a fixing film, and fixing the developed image of the toner on the recording element by heating. C) The maximum value of the endothermic peak of the toner measured by DSC. A heat fixing method, characterized in that the adhesive film is peeled off from the fixing surface of the toner at a higher temperature. 2. The heat fixing method according to claim 1, wherein the fixing film is a heat resistant film having a release agent 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 by applying a pulsed waveform to the resistance element while detecting the temperature by the temperature measuring element. The heat fixing method according to claim 1, wherein the heating body is heated. 4. A toner image is formed on the recording body by a fixedly supported heating body and a pressing member which is in pressure contact with the heating body and presses the recording body to the heating body through a fixing film. In a toner used in a heat fixing method in which the fixing film is peeled off from the fixing surface of the toner at a temperature higher than the maximum value of the endothermic peak of the toner measured by DSC, the toner is etherified. A toner containing a polyester resin and a release agent obtained by copolycondensation of a bisphenol and a carboxylic acid selected from the group consisting of divalent or higher carboxylic acids, their anhydrides and their lower alkyl esters. (I) The melt viscosity η ′ of the polyester resin by a hot overhead flow tester is 10 ³ to 10 ⁶ P (poise) at any temperature in the temperature range of 80 ° C. to 120 ° C., and 80 ° C., 120 ° C. When the natural logarithm (lnη ′) of the melt viscosity at ℃ is plotted against temperature, it has the physical property that the absolute value of the slope of the graph is 0.50 ln (poise) / ℃ or less, and
(Ii) the release agent is an aromatic vinyl monomer having a melt viscosity of 1 to 250 cp (centipoise) at 160 ° C. and a polyolefin graft-modified with an unsaturated fatty acid or an unsaturated fatty acid ester, A heat-fixing toner containing 0.1 to 20% by weight based on the amount of resin.