JPH0812455B2 - 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. The present invention relates to a capsule 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 and Actions for Solving the Problems] Specifically, the present invention uses a capsule toner in which the surface of core particles mainly composed of a binder resin and a colorant is coated with a resin, and a visible image of the capsule toner is used. In the method of heating and fixing the recording medium onto a recording material, a) the binder resin binds a polymer produced from one or more monomers selected from aromatic vinyl monomers, acrylic acid ester monomers, and methacrylic acid ester monomers. It is contained as a resin, and the binder resin has a melt viscosity of 10 ^{3 at the} 50% outflow point measured by an elevated flow tester.
Physical property of ~ 10 ⁵ poise and absolute value of the slope of the graph at the 50% outflow point when the logarithm of melt viscosity (lnη ') is plotted against temperature (℃) is 1.0 ln (poise) / ℃ or less B) a fixedly supported heating body and a pressing member that is in pressure contact with the heating body and presses the recording material to the heating body through a fixing film. The image is heated and fixed on the recording material, and c) the surface temperature T ₃ of the fixing film at the portion separated from the toner fixing surface is higher than the endothermic temperature T _{D of the} capsule toner.
The present invention relates to a heat fixing method, which comprises peeling the fixing film from the toner fixing surface under the condition of having a high temperature of 30 ° C. or higher.

Further, according to the present invention, a visualized image of a capsule toner is applied to a recording material by a fixedly supported heating element and a pressing member that is in pressure contact with the heating element and brings the recording material into close contact with the heating element via a fixing film. When the surface temperature T ₃ of the fixing film in the portion which is heat-fixed and peels off from the toner fixing surface is 30 ° C. or more higher than the endothermic temperature T _D of the capsule toner, the fixing film is fixed on the toner fixing surface. A capsule toner used in a fixing method of peeling from a core, wherein the capsule toner is 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 the binder resin is an aromatic toner. A binder resin containing a polymer produced from one or more monomers selected from vinylic monomers, acrylic acid ester monomers and methacrylic acid ester monomers, By elevated type flow tester measurement
The melt viscosity at the 50% pour point was 10 ³ to 10 ⁵ poise, and when the logarithm (lnη ′) of the melt viscosity was plotted against the temperature (° C), the absolute value of the slope of the graph at the 50% pour point was 1.0. The present invention relates to a heat fixing capsule toner, which has a characteristic of not more than ln (poise) / ° C.

In Japanese Patent Application No. 62-147884 previously provided by the present applicant, a toner image is heated through a moving heat-resistant sheet by a heating element of low heat capacity that is energized and heated in a pulse shape, and is fixed on a recording material. By fixing device to fix,
An image forming apparatus having a short wait time and low power consumption has been proposed. Similarly, Japanese Patent Application No. 63-63 previously proposed by the applicant.
-12069, in a fixing device that heat-fixes a visible image of a toner on 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, so that the offset phenomenon is effective. A fixing device for preventing the above has been proposed.

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.

 Hereinafter, the present invention will be described in detail.

One of the structural features of the heat fixing method of the present invention is that the core binder resin is 50% as measured by an elevated flow tester.
When the melt viscosity at the pour point is 10 ³ to 10 ⁵ poise and the logarithm (lnη) of the melt viscosity is plotted against temperature, the absolute value of the slope of the graph at the 50% pour point is 1.0 ln.
(Poise) / ° C.

The melt viscosity in the present invention is measured by an elevated flow tester (Shimadzu CFT-500 as shown in FIG. 1).
Shape). 1.5g molded using a pressure molding machine
Apply a load of 10 kgf with a plunger at a constant temperature and push it out from a nozzle with a diameter of 1 mm and a length of 1 mm,
In this way, the plunger descent amount (flow rate) of the flow tester is measured.

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 the melt viscosity is high (10 ⁵ p
Oise or higher) causes less fixing due to less particle deformation during heat fixing and does not increase adhesiveness, and a large amount of energy is required to compensate for this. On the other hand, if it is low (10 ³ poise or more), bleeding on the transfer paper or
Penetration into the transfer paper is likely to occur. Also, if the “inclination” 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 latitude of the fixing temperature cannot be set sufficiently and fixing failure may occur. Penetration easily occurs. Furthermore, the fixing processing speed (mm / sec)
Dependency on. 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 toner used in the heat fixing method of the present invention is a capsule type toner in which the core particles having the above characteristics are coated with a resin. Since the core material can contain a low molecular weight component that is softened at a lower temperature because it is protected by the shell material, it is possible to substantially lower the fixing temperature while maintaining the blocking property and the storage property. Further, since it is covered with a uniform shell material, it has an advantage that it has excellent fluidity and chargeability.

Examples of the monomer constituting the main component of the binder resin of the toner applied to the present invention include styrene such as styrene, α-methylstyrene, p-chlorostyrene and its substitution products, acrylic acid, methyl acrylate, and acrylic. Two such as ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, etc. A monocarboxylic acid having a heavy bond or a substituted product thereof, for example, a dicarboxylic acid having a double bond such as maleic acid, butyl maleate, methyl maleate, dimethyl maleate and the like, and a substituted product thereof, for example, vinyl chloride, vinyl acetate,
Vinyl esters such as vinyl benzoate, vinyl ketones such as vinyl methyl ketone, vinyl excyl ketone, etc. Vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, butadiene, etc. Vinyl monomers may be used alone or in combination of two or more.

In addition to the binder resin component, the core particles used in the present invention may contain the following compounds in a proportion smaller than the content of the binder resin component. For example, silicone resin, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc. Is.

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%.

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 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 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 half ester of maleic anhydride , 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 covered with, for example, a zinc oxide photosensitive layer or an organic semiconductor photosensitive layer. Drum 4 uniformly charged by this charger 5
The element array 2 forms an electrostatic image subjected to image exposure. This electrostatic latent image is visualized by the developing device 6 by using a toner made of a resin or the like which is softened and melted by heating. On the other hand, the sheets P stored in the cassette S
Is fed onto the drum 4 by a pair of conveying rollers 8 which are rotated in pressure contact with each other in the vertical direction at a timing synchronized with the feeding roller 7 and the image on the photosensitive drum 4.
Then, the transfer discharger 9 transfers the toner image formed on the photosensitive drum 4 onto the sheet P. After that, the sheet P separated from the drum 4 by the known separating means is guided to the fixing device 11 by the conveyance guide 10 and subjected to heat fixing processing, and then discharged onto the tray 12. In addition,
After transferring the toner image, the residual toner on the drum 4 is 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 apparatus, and as an example, an alumina substrate 21 having a thickness of 1.0 mm, a width of 10 mm and a longitudinal length of 240 mm is coated with a resistance material 22 in a width of 1.0 mm. Power is applied from both ends. Energization is a pulsed waveform with a cycle of 20 msec of DC 100 V and is given by varying the pulse width according to a desired temperature and energy release amount controlled by the temperature measuring element 23. The approximate pulse width is 0.5 msec to 5 msec. Further, when the temperature detected by the temperature detecting 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 by about 10 to 30 ° C. 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
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.

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 preferably higher than the endothermic temperature, more preferably 30 ° C. or more (more preferably 40 to 150 ° C.) higher than the endothermic temperature. It is preferable to peel under the conditions.

When the surface temperature T ₃ of the fixing film is lower than the endothermic temperature T _D + 30 ° C. of the capsule toner, it becomes difficult to peel the fixing film from the toner fixing surface smoothly, and therefore the surface condition of the toner fixing surface is The non-uniformity is likely to occur, and the adhesion between the surface of the fixing film and the toner fixing surface is increased, so that 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,
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.

Example An example of manufacturing a toner sample is shown below. All parts are parts by weight.

(Sample A) The above components were melt-kneaded by a twin-screw kneading extruder, cooled, crushed by an airflow crusher, and classified by an air classifier to obtain core material particles having an average particle size of 10.6 μm.

 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 a gelatin shell material having a 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 is spray-dried (inlet temperature 150 ° C,
Encapsulation was performed using an outlet temperature of 100 ° C. and an air flow rate of 10 m / min, a two-fluid nozzle type). This obtained capsule toner 10
Sample A by externally mixing 0.6 parts of colloidal silica with 0 part
I got

(Sample B) The above components were treated in the same manner as in Sample A to obtain Capsule Toner Sample B.

(Sample C) The above components were treated in the same manner as in Sample A to obtain Capsule Toner Sample C.

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.

Example 1 In this fixing device, the surface temperature of the heating element is 160 ° C., the power consumption of the resistance material in the heating part is 150 W, the total pressure of the heating roller is 7 kg, the nip between the pressure roller and the film is 3 mm, and the fixing processing speed (ps ) 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 is added to PTFE is used on the contact surface with the recording material.

At this time, the time required to reach the surface temperature of the heating body of 160 ° C. was about 1.5 sec.

Sample A was applied to an improved machine of a commercially available copying machine Canon NP150Z (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 Silvol 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 3.2%) 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 the roll was rotating, the surface temperature rose to 140 ° 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 kept above 160 ℃. At this time, the time required for the surface temperature of the heat roller to rise from room temperature to 160 ° C. was 20 seconds, and it took some time to be kept at a constant temperature by temperature control. 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 is 200 at the initial stage and after 200 sheets, and the density reduction rate is 2 to 6% (3.5% on average), which is almost the same as in Example 1.
At the time of sheet passing, a gap on the image due to the offset phenomenon was already observed, and at the time of 4000 sheets, the back side stain was generated on the transfer sheet. 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 180 ° C
It was set to become. At this time, the surface temperature of the heating
The time required to reach 0 ° C was about 1.6 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.
c, and the roller surface temperature was set to 180 ° C.
At this time, the time required for the roller surface temperature to reach 180 ° C. was about 27 seconds.

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 conducted 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 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 4 Using toner sample C, a fixing test was conducted 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 within the agency FI Technical display location G03G 13/20 15/20 101 G03G 9/08 (72) Inventor Satoshi Matsunaga 3 Shimomaruko Ota-ku, Tokyo Canon No. 30-2 Canon Inc. (56) Reference JP 59-68766 (JP, A) JP 59-157678 (JP, A) JP 63-128361 (JP, A) JP Sho 63-128357 (JP, A) JP 61-215558 (JP, A) JP 61-215557 (JP, A) JP 63-58358 (JP, A)

Claims (4)

[Claims] 1. A method of heat-fixing a visible image of a capsule toner to a recording material using a capsule toner having a core particle surface containing a binder resin and a colorant as a main component coated with a resin, comprising: a) the binder The resin contains a polymer produced from one or more kinds of monomers selected from aromatic vinyl monomers, acrylic acid ester monomers, and methacrylic acid ester monomers as a binder resin, and the binder resin is an elevated flow tester measurement. Has a melt viscosity of 10 ^{3 at} 50% pour point
Physical property of ~ 10 ⁵ poise and absolute value of the slope of the graph at the 50% outflow point when the logarithm of melt viscosity (lnη ') is plotted against temperature (℃) is 1.0 ln (poise) / ℃ or less B) a fixedly supported heating element and a pressing member that is in pressure contact with the heating element and presses the recording material to the heating element through a fixing film. The image is heated and fixed on the recording material, and c) the surface temperature T ₃ of the fixing film at the portion separated from the toner fixing surface is higher than the endothermic temperature T _{D of the} capsule toner.
A heating and fixing method, characterized in that the fixing film is peeled from the toner fixing surface under the condition of having a high temperature of 30 ° C. or higher. 2. The heat fixing method according to claim 1, wherein the fixing film is a heat resistant film having a release layer on the toner fixing surface side. 3. The heating element is a linear heating element having a temperature measuring element and a resistance material in the length direction, and while heating the temperature by the temperature measuring element, energization of a pulse waveform is applied to the resistance material to heat the heating element. The heat fixing method according to claim 1, wherein the body is heated. 4. A visible image of capsule toner is heated on a recording material by a fixedly supported heating element and a pressing member that is in pressure contact with the heating element and presses the recording material in close contact with the heating element via a fixing film. In the state where the surface temperature T ₃ of the fixing film in the portion which is fixed and peeled off from the toner fixing surface is higher than the endothermic temperature T _D of the capsule toner by 30 ° C. or more,
A capsule toner used in a fixing method of peeling the fixing film from a toner fixing surface, wherein the capsule toner is a capsule toner in which a core particle surface containing a binder resin and a colorant as a main component is coated with a resin, The binder resin contains, as a binder resin, a polymer produced from one or more monomers selected from aromatic vinyl monomers, acrylic acid ester monomers and methacrylic acid ester monomers, and the binder resin is elevated. 50% measured by a flow tester
When the melt viscosity at the pour point is 10 ³ to 10 ⁵ poise and the logarithm of the melt viscosity (lnη ′) is plotted against the temperature (° C), the absolute value of the slope of the graph at the 50% pour point is 1.
A heat fixing capsule toner having a characteristic of 0 ln (poise) / ° C. or less.