JPH087509B2 - Fixing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fixing device in an image forming apparatus such as a copying machine, a laser beam printer, a facsimile, a microfilm reader printer, an image display (display) device, and a recording machine. .

More specifically, a recording material (electrofax sheet, electrostatic recording sheet, transfer material sheet, transfer material sheet, etc.) is formed by using a toner made of a heat-meltable resin by an appropriate image forming process means such as electrophotography, electrostatic recording, magnetic recording, etc. An unfixed toner image corresponding to desired image information is formed and carried on a surface of a printing paper or the like by a direct method or an indirect (transfer) method, and the unfixed toner image is carried on a recording material surface carrying the image. In particular, the present invention relates to a fixing device in an image forming apparatus of a type in which heat fixing processing is performed as a permanently fixed image.

(Prior Art) Conventionally, a fixing device used in this type of image forming apparatus includes a heating roller maintained at a predetermined temperature and a pressing roller having an elastic layer and pressing against the heating roller. ,
A roller fixing method in which a recording material on which an unfixed toner image is formed is heated while being nipped and conveyed is often used.

A belt fixing system as disclosed in U.S. Pat. No. 3,578,797 is also known. This is because the toner image is brought into contact with the heating element web and is heated to its melting point to be melted, and after the melting, the toner is cooled to have a relatively high viscosity, and the toner adhesion tendency is weakened from the heating element web. It is a method of fixing without causing offset by going through the process of peeling.

(Problems to be Solved by the Invention) However, the conventional thermal roll fixing method as described above,
The belt fixing method has the following problems.

Heat roll fixing method It takes a long time to rise to a predetermined temperature,
During that time, the image forming operation is prohibited. That is, there is a so-called wait time.

 A large amount of electric power is required because a heat capacity is required.

A high heat-resistant roller bearing requires a heat-resistant special bearing.

The roller comes into direct contact with the hands, which is dangerous and requires a protective member.

The recording material is wrapped around the roller due to the constant temperature and the curvature of the roller, so that a jam problem of the recording material is easily observed.

Belt fixing method This method also has the same problems as those of the above-described heat roller fixing method, such as the wait time and large power consumption.

The present invention solves the problems that the above-described conventional device has, and makes it possible to reduce the heat capacity of the heating element without causing fixing failure or offset, and as a result, standby time or power consumption, and further An object of the present invention is to provide a fixing device having a small temperature rise in the machine and having other remarkable features.

(Means for Solving the Problems) The present invention has a heating body that generates heat when energized, and a film in which one surface slides on the heating body and the other surface contacts a recording material and moves together. In a fixing device that heats and fixes an unfixed image on a recording material by heat from the heating body through the film, when stopping the fixing operation, the power supply to the heating body is cut off while the film is moving, and then, A fixing device, characterized in that the movement of the film is stopped.

(Operation) (1) The recording material to be image-fixed, which is introduced between the fixing film and the pressure member, which is driven to run in the same direction at the same speed as the conveying direction of the recording material, is the unfixed toner on the fixing film surface. While the image-bearing surface is in close contact with the fixing film and the overlapping state with the fixing film, the pressure difference between the heating member and the pressing member (fixing nip portion) is applied while the surface pressure difference occurs between the heating member and the pressing member, and wrinkles occur. They do not get close to each other, and they pass over each other in close contact with each other.

In the heating step, the unfixed toner image on the surface of the recording material is heated and softened and melted by the heating body through the fixing film, and in particular, the surface layer portion thereof is much higher than the melting point of the toner and completely softened and melted. In this case, the heating element, fixing film, toner image,
The recording material is satisfactorily pressed and adhered by the pressing member, and heat is effectively transferred, so that the toner is sufficiently softened and melted by heating for a short time, and good fixing properties are obtained. On the other hand, the temperature rise of the recording material itself is practically small, and the waste of thermal energy is small. In other words, the recording material itself is not heated substantially, and only the toner is heated and softened and melted effectively, and the heat fixing of the toner image can be satisfactorily executed with low power.

A note will now be given regarding the softening / melting of the toner described in the present invention. The temperature that is conveniently expressed as the "melting point" of the toner means the minimum temperature required for the toner to be fixed. There is a case where the viscosity is reduced to such an extent. Therefore, even if it is expressed as melting when fixing, it may actually show a decrease in viscosity such as softening. The present invention also includes such a case. Similarly, even when it is expressed for convenience that the toner has been cooled and fixed, it may be more appropriate for some toners not to be solidified but to have higher viscosity. The present invention also includes such a case.

Cooling process Sequentially passes through the mutual pressure contact area between the heating element and the pressure member in close contact with the fixing film surface.The recording material part that has been softened / melted by the toner image remains in close contact with the fixing film surface after passing through the pressure contact area. Is continuously continued for a while, and a cooling step is performed during this period to radiate heat of the toner softened and melted in the heating step to cool and fix the toner. Due to this cooling and solidification, the cohesive force of the toner becomes very large, and the toner behaves as a group, and the adhesiveness / fixing force to the recording material side increases, while that to the fixing film side extremely decreases. When the recording material is heated and softened and melted in the heating step, the toner is pressed by the pressure member, so at least a part of the toner image penetrates into the surface layer of the recording material, and the solidified portion is cooled and solidified. Due to the anchor effect, the adhesion and fixing force of the cooled and solidified toner to the recording material side increases.

Separation (Separation) Step After the toner image is cooled and solidified by the cooling step, the recording material is sequentially separated from the fixing film surface.
At the time of this separation, the toner image is cooled and solidified to have a sufficiently large adhesion / adhesion force to the recording material and an extremely small amount to the fixing film, so that the recording material portion on which the image is fixed causes toner offset to the fixing film. It can be easily and sequentially separated.

In this way, the recording material to be image-fixed is run in close contact with the fixing film at the same speed so that the unfixed toner image bearing surface faces the surface of the running fixing film, and the toner image is heated and melted by the heating body through the fixing film. At the very least, since the recording material and the fixing film are separated from each other after the toner image is cooled and fixed, the toner offset does not occur on the fixing film and the heating element having a small heat capacity is used, and the power is supplied to the heating element. It becomes possible to carry out with a simple structure, and by maintaining a heating body of a sufficiently high temperature with respect to the temperature (melting point or softening point) at which the toner should be heated for fixing, toner image efficiency can be improved. It is possible to heat the target effectively, and it is possible to perform sufficiently good fixing without defective fixing with a small amount of energy. As a result,
It is possible to obtain an image forming apparatus having a small standby time when the apparatus is used, power consumption, and a small temperature rise in the machine.

Of the three steps of heating, cooling, and separation, if the toner is sufficiently melted at a high temperature (if the viscosity of the toner when heated and melted is sufficiently high), the toner is sufficiently melted at a high temperature in the heating step. Immediately (when the toner temperature is equal to or higher than the melting point), the recording material may be separated from the surface of the fixing film, and the cooling step after the heating step may be eliminated, and it belongs to the category of the present invention.

(2) In order to move and move the fixing film without causing wrinkles, it is necessary to always apply tension.
However, if the fixing film is held at a high temperature and under tension for a long time, it may be deformed (heat-damaged) due to a creep phenomenon or the like. Since the heating time per unit area received by the heating element when the fixing film is running is short, the fixing film causes a temperature gradient in the thickness direction, and the temperature of the surface of the fixing film that contacts the toner rises only to a temperature lower than that of the heating element. Although the degree of heat damage is low, if the fixing film is pressed against the heating body for a long time without moving the fixing film, that is, in the state where the traveling is stopped, the fixing film portion pressed against the heating body is intensively heated. The film portion overheats to the surface side in contact with the toner to a temperature substantially the same as that of the heating body, causing thermal damage. When the fixing film is a composite layer type fixing film having a surface layer on the side in contact with the toner, the fixing film is susceptible to thermal damage such as deformation of the surface layer or peeling of the surface layer.

According to the present invention, as described above, the fixing film is drive-controlled so as not to stop traveling when the heating body is heated, that is, when the heating body is heated, the fixing film is drive-controlled so as to always be in a traveling movement state. It prevents the occurrence of local overheating, and minimizes the heat damage to the fixing film to improve the durability of the fixing film. (Embodiment) The apparatus of this embodiment is a reciprocating type / rotating drum type / transfer type electrophotographic copying apparatus.

(1) Overall schematic configuration of the apparatus (FIG. 1) In FIG. 1, 100 is a machine casing of the apparatus, 1 is a reciprocating motion made of a transparent plate member such as a glass plate disposed on a top plate 100a of the machine casing. This is a type document placing table, and is reciprocatingly driven on the machine casing upper surface plate 100a at a predetermined speed to the right a and the left a'in the drawing.

G is an original, which is placed on the upper surface of the original placing table 1 with the image surface side to be copied facing downward according to a predetermined placing reference,
The original pressure plate 1a is placed on top of it and pressed down to set it.

Reference numeral 100b denotes a slit opening serving as a document illuminating section which is opened on the surface of the machine housing upper surface plate 100a with a direction perpendicular to the reciprocating direction of the document placing table 1 (direction perpendicular to the paper surface) as a longitudinal direction. The downward image surface of the document G placed and set on the document placing table 1 sequentially passes through the position of the slit opening 100b from the right side to the left side in the process of reciprocating to the right a of the document placing table 1. In the course of the passage, the light L of the lamp 7 is received through the slit opening 100b and the transparent document placing table 1 to be illuminated and scanned. The light reflected from the document surface of the illumination scanning light is image-wise exposed on the surface of the photosensitive drum 3 by the short-focus small-diameter image-forming element array 2.

The photosensitive drum 3 is coated with a photosensitive layer such as a zinc oxide photosensitive layer or an organic semiconductor photosensitive layer, and is driven to rotate clockwise as indicated by an arrow b at a predetermined peripheral speed around a center support shaft 3a. The charger 4 was subjected to a uniform charging process of positive or negative polarity, and the uniformly charged surface was subjected to the image forming exposure (slit exposure) of the original image to form an image on the surface of the photosensitive drum 3. An electrostatic latent image corresponding to a document image is sequentially formed.

The electrostatic latent image is sequentially visualized by the developing device 5 with toner made of resin or the like which is softened and melted by heating, and the toner image as the visualized image is transferred to a portion where the transfer discharger 8 as a transfer portion is provided. I will do it.

Reference numeral S denotes a cassette in which transfer material sheets P as recording materials are stacked and housed, the sheets in the cassette are fed out and fed one by one by the rotation of the feeding roller 6, and then the toner on the drum 3 is fed by the registration roller 9. When the front end of the image forming portion reaches the portion of the transfer discharger 8, the front end of the transfer material sheet P also reaches the position between the transfer discharger 8 and the photosensitive drum 3 and is timed so that they coincide with each other. Delivered synchronously. Then, the toner image on the photosensitive drum 3 side is sequentially transferred to the surface of the sheet by the transfer discharger 8.

The sheet to which the toner image has been transferred at the transfer portion is sequentially separated from the surface of the photosensitive drum 3 by separation means (not shown), and is guided to a fixing device 11 described later by a conveyance guide 10 to heat an unfixed toner image carried on the sheet. After undergoing the fixing process, the image is discharged onto the discharge tray 12 outside the machine as an image formed product (copy).

On the other hand, the surface of the photosensitive drum 3 after the transfer of the toner image is repeatedly used for image formation after the adhering contaminants such as the transfer residual toner are removed by the cleaning device 13.

(2) Fixing device (FIGS. 1 and 2) 24 is an endless belt-shaped fixing film, and includes a left driving roller 25, a right driven roller 26, and a driving roller.
25 between the separating roller 27 arranged below the driving roller 25 and the driven roller 26, and between the four members 25, 26, 27, 20 parallel to each other of the low heating capacity linear heating body 20 as a heating body arranged below It is suspended around.

The driven roller 26 is an endless belt-shaped fixing film 24.
The fixing film that doubles as the tension roller
Reference numeral 24 denotes a transfer material sheet P having an unfixed toner image Ta, which is conveyed from the image forming portion 8 side, on the upper surface thereof at a predetermined peripheral speed in the clockwise direction as the driving roller 25 is rotated clockwise.
It is driven to rotate without wrinkling, meandering, or speed delay at the same peripheral speed as the transport speed of.

Reference numeral 28 denotes a pressure roller having a rubber elastic layer having a good releasability such as silicon rubber as a pressure member, and sandwiching the film portion on the descending side of the endless belt-shaped fixing film 24 of the heating body 20. The lower surface is brought into counter-pressure contact with an urging means (not shown) with a total pressure of 4 to 7 kg, and rotates counterclockwise in the forward direction of the transfer material sheet P conveyance direction.

Endless belt-shaped fixing film 24 driven to rotate
Is repeatedly used for heat-fixing toner images, so it has excellent heat resistance, releasability, and durability, and is generally 100 μm or less.
It is preferable to use a thin film having a thickness of 50 μm or less. For example, a single layer film of a heat-resistant resin such as polyimide / polyetherimide / PEA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin) or a composite layer film, for example, a 20 μm thick film at least on the side of the image contact surface with PTFE ( For example, a release coat layer having a conductive material added to a tetrafluoroethylene resin) is applied to a thickness of 10 μm.

A low heat capacity linear heating element as a heating element has, for example, a thickness of 1.
Along the length, an electrical resistance material such as Ta ₂ N is formed along the length of the lower surface of the alumina substrate 21 having a width of 0 mm, a width of 10 mm, and a length of 240 mm.
It is provided with a linear or band-shaped heating element 22 coated on 1.0 mm. In the case of this example, the linear or strip heating element 22 is energized from both longitudinal end portions thereof to heat the heating element 22 over the entire length. Electricity is DC100V odor
With a 20 msec pulse-shaped waveform, the desired temperature controlled by the temperature detection thermistor 23 pressed against the back side of the substrate,
It has an energization control circuit configuration that gives a pulse according to the amount of energy released by changing its pulse width.
The heating element 22 is controlled within a range of 0.5 to 5 msec, and the temperature of the heating element 22 is instantly raised to about 200 to 300 ° C each time a pulse is input.

In this example, the temperature of the heater composed of the substrate 21 and the heating element 22, that is, the temperature of the heating element, is measured by the thermistor 23, and the measured value is input to the control circuit 30 (Fig. 5) for calculation in the control circuit. Based on the control of the energizing circuit 31 for the heating element 22, the temperature of the heating element is adjusted to 200 °.

The fixing film 24 is not limited to the endless belt shape,
As shown in the figure, the end fixing film 24 wound around the delivery shaft 30 in a roll winding is locked between the heating body 20 and the pressure roller 28 and under the separation roller 27 and the winding shaft 31. The transfer material sheet P may be moved from the delivery shaft 30 side to the winding shaft 31 side at the same speed as the conveyance speed of the transfer material sheet P.

(3) Fixing Execution Operation The image forming start signal of the apparatus causes the apparatus to perform the image forming operation, and the leading end of the transfer material sheet P having the unfixed toner image Ta carried on the upper surface is conveyed to the fixing apparatus 11 from the fixing apparatus. When it is detected by the sheet sensor 32 (FIGS. 2 and 3) arranged nearer, the drive control roller 33 starts the rotational movement (travel movement) with the fixing film 24. This start time t ₁
Time point t ₂ when a predetermined timer time has elapsed from (Fig. 6) (0.
After 5 seconds), the energization of the heating element 22 of the heating element 20 is started, and the heating element is heated and temperature controlled.

The transfer material sheet P is guided by the guide 29 and the fixing film 24 and the pressure roller at the pressure contact portion N between the heating body 20 and the pressure roller 28.
22 and the unfixed toner image surface adheres to the lower surface of the fixing film 24 in the state of surface movement in the same direction at the same speed as the conveyance speed of the sheet P without causing surface deviation or wrinkling. In the overlapping state with the film 24, the heating body 20 and the pressure roller 28 pass between the mutual pressure contact portions N while receiving a sandwiching pressure. The toner image is heated and softened and melted as described in the item (1)-of the above-mentioned (action) as a heating step in the process of passing through the mutual pressing portion. As described above, the heating step in this embodiment is performed by providing the heating element 20 with the linear heating element 22 and
This is performed by a heating body 21 configured to repeatedly generate heat by energizing the heating element 22 having a low heat capacity integrally formed with the above in a pulsed manner. In other words, the toner image Ta on the sheet P conveyed at the predetermined conveying speed, together with the fixing film 24 on which the sheet P is conveyed, is a linear heating unit which is sequentially determined according to the width of the heating element 22 of the heating element 20. After being fed into the effective width W and receiving heat, it becomes a softened / melted image Tb.

The sheet portion that has passed through the mutual pressure contact portion N between the heating body 20 and the pressure roller 28 is stretched between the heating body 20 and the separation roller 27 until it reaches the position of the separation roller 27. The film is continuously conveyed while being in close contact with it.

This transportation process is referred to as the cooling process in (1) of (Operation) above.
As described in the section, the heat of the softened / melted toner Tb is radiated to cool and solidify the toner Tc.

When the fixing film 24 reaches the position of the separation roller pair 27, the traveling direction of the fixing film 24 is turned along the surface of the separation roller 27 having a large curvature in a direction away from the surface of the sheet P, and the fixing film 24 and the sheet P are separated from each other ( After separation, the sheet P is discharged to the discharge tray 11. By the time of the separation, the toner is sufficiently cooled and solidified, and the above (action) (1)-
As described in the section, the adhesion and fixing force of the toner to the sheet P is sufficiently large, and the adhesion to the fixing film 24 is extremely small. Therefore, the separation between the fixing film 24 and the sheet P substantially causes the toner offset to the fixing film 24. It can be easily and sequentially performed without accidentally occurring.

At the time point t ₃ when the discharge of the fixed sheet P is detected by the sheet trailing edge passage detection sensor 34 (FIG. 1), the power supply to the heating element 22 of the heating element 20 is cut off, and from that time point t _{3 a} predetermined time is reached. The driving of the fixing film 24 is stopped at the time point t ₄ (0.5 seconds later in this example) when the timer time elapses.

In the present embodiment, the linear heating element 22 of the heating element 20 is instantly heated to a sufficiently high temperature with respect to the melting point (or fixing temperature) of the toner by energization, so that preheating of the heating element is unnecessary. There is little heat transfer to the pressure roller 28 during non-fixing. Also, at the time of fixing, a fixing film, a toner image, and a sheet are interposed between the heating body 20 and the pressure roller 28, and a sharp temperature gradient occurs due to a short heat generation time.
It is difficult for the pressure roller 28 to raise its temperature, and the temperature is maintained below the melting point of the toner even when continuous image formation is carried out to the extent practically required. In the apparatus of this embodiment having such a configuration, the toner image formed of the heat-fusible toner on the sheet P is first heated and melted by the heating body 20 via the fixing film 24, and particularly, the surface portion thereof is completely removed. Softens and melts.
At this time, a heating roller, a fixing film,
The toner image and the sheet are in good contact with each other, and heat is efficiently transferred. Accordingly, the heating of the sheet P itself can be suppressed as much as possible, and the toner image can be efficiently heated and melted,
In particular, energy can be saved by limiting the heating time for energization.

Since the heating body is small enough, the heat capacity is small, and it is not necessary to raise the temperature of the heating body in advance. Therefore, the power consumption during non-image formation can be reduced, and the temperature rise in the apparatus can be prevented. .

In the present embodiment, since the temperature of the pressure roller 28 is maintained lower than the melting point of the toner as described above, it is possible to promote the heat radiation of the toner image in the cooling step following the toner image heating step. . Therefore, the time required for cooling is short and the device can be downsized.

As in the operation sequence shown in FIG. 6, the start of fixing starts driving (rotation or traveling movement) of the fixing film 24, then the heating body 20 is electrically heated to perform fixing, and the fixing is completed by the heating body. By turning off the power supply to the fixing film and then stopping the driving of the fixing film, the fixing film always moves when the heating body is heated, and the fixing film is not locally heated and the film is not damaged by heat. It is possible to improve durability with almost no.

In an image forming apparatus in which the image forming apparatus operates almost accurately without error, driving of the fixing film and heating of the heating body may be started at the same time and stopped at the same time.

Further, in the apparatus of the present embodiment, even when the apparatus is stopped due to some trouble such as poor transfer sheet transfer,
As shown by the broken line in the figure, the heating of the heating body is prohibited from the starting time t _A of the emergency signal A, and then a predetermined time elapses t _a (0.
After 5 seconds, the fixing film drive is stopped.

When the fixing film is not driven t ₄ (t _a ) after the heating body has been de-energized t ₃ (A), it is detected that the heating body has been sufficiently cooled (for example, 100 ° C or less) due to the de-energization of the heating body. If it is detected by the thermistor 23, it is also effective to perform the operation according to it.

That is, when the fixing process is continued for a long time, the heating element may store heat, and the temperature may not be lowered immediately after stopping the energization. As described above, the above configuration can prevent thermal damage caused by the fixing film being stopped and press-contacted with the heating body that has not sufficiently lowered the temperature, and the durability can be further improved.

(5) Others When the end film is used as the fixing film 24 as shown in FIG. 3, a new roll winding film is used when the fixing film on the shaft side is fed out and almost all is wound on the winding shaft side and used. It is also possible to use a method of exchanging with (winding exchange type).

In the case of such a take-up exchange type, the thickness can be reduced regardless of the durability of the fixing film, and the power consumption can be reduced. For example, an inexpensive base material such as a PET (polyester) film or the like may be used as the fixing film, and a heat-treated thin film having a thickness of about 12.5 μm or less may be used.

Or, since the toner offset to the fixing film surface does not substantially occur as described above, if the thermal deformation or deterioration accompanying the use of the fixing film is small, the used sheet wound on the take-up shaft side can be removed in a timely manner. And rewinding control to the shaft side,
Alternatively, it can be used a plurality of times by reversing the winding shaft side and the sending shaft side, etc. (rewinding repetitive use type).

In the rewinding and reusing type, for example, as a fixing film, a polyimide resin film having a thickness of 25 μm is used as a base material having excellent heat resistance and mechanical strength, and a release layer made of fluorine resin or the like having a high releasing property on its surface. The composite layer film provided with can be used, and it is preferable that the pressure release mechanism is automatically controlled during the backward rewinding and the pressure contact between the heating body and the pressure roller is maintained in the released state.

In the case of multiple use such as a rewinding repetitive use type or an endless belt type, a felt pad is provided for cleaning the film surface, and a slight release agent, for example, silicon oil is impregnated to contact the pad with the film surface. For example, the film surface may be cleaned and the releasability may be further improved. When the fixing film is an insulative fluororesin-treated product, static electricity that disturbs the toner image is easily generated in the film. Therefore, it is also possible to remove the static electricity with a grounded static elimination brush. A bias voltage may be applied to the brush without being grounded to charge the film within a range that does not disturb the toner image. Further, it is one measure to add conductive powder fibers, for example, carbon black or the like, to the fluororesin to prevent the above-mentioned image disturbance due to static electricity. In addition, depressurization and conductivity of the pressure roller can be performed by the same means. Further, an antistatic agent or the like may be applied or added.

Fixing film is endless belt type, rewindable type,
Regardless of the rewinding and reusing type, the fixing film can be easily replaced at a predetermined portion of the fixing device 11 so that the fixing film can be easily replaced.

The structure of the heating element 20 and the control of energization to the heating element 22 are not limited to those of the embodiment, the heating element 20 may be a heat roller type, and the heating element 22 has a thick film resistor or a PTC characteristic. It may be a ceramic chip array or the like, and the energization control may not be given in a pulsed manner, but may be normal AC energization.

The cooling and solidification of the toner heated and melted in the heating step may be performed by natural heat radiation, or may be performed by forced cooling by arranging a blowing means, a heat radiation fin, or the like.

If the toner is sufficiently melted at a high temperature, as shown in FIG. 7, if the toner is melted at a sufficiently high temperature in a heating step (fixing nip portion), the recording material (transfer material) is immediately transferred without a cooling step after the heating step. The sheet P may be separated from the fixing film 24 surface.

The apparatus of the above embodiment is a transfer type electronic copying apparatus,
Image forming process and means are electrofax paper
An image is formed on the recording material by a heat-meltable toner by a direct method in which a toner image is directly formed and carried on an electrostatic recording paper or the like, a magnetic recording image forming method, or other appropriate image forming process / means, and the image is heated. The present invention can be effectively applied to various image forming apparatuses such as a fixing type copying machine, a laser beam printer, a facsimile, a microfilm reader printer, a display device, and a recording machine.

(Effects of the Invention) As described above, according to the present invention, in the toner image heating and fixing device, it is possible to reduce the heat capacity of the heating member, which is the heating means, without causing the fixing failure or the offset, the standby time and the power consumption, Further, it is possible to realize an image forming apparatus capable of constantly and stably outputting an image formed article having a good fixed image quality with a small temperature rise inside the apparatus. Further, the fixing film can be repeatedly used for a long period of time without any problem of wrinkling and without any problem.

Further, the fixing film is prevented from being locally overheated and suffered from heat damage, and the durability is improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing a schematic configuration of an apparatus of one embodiment, FIG. 2 is an enlarged view of a fixing device portion, FIG. 3 is a schematic view of another configuration example of the fixing device, and FIG. Cross-sectional model diagram, FIG. 5 is a block diagram of the control system, FIG. 6 is an operation sequence, and FIG.
The figure is a schematic view of another configuration example of the fixing device. Reference numeral 3 denotes a drum-type rotating photoconductor, 11 denotes a fixing device, 24 denotes a fixing film, 20 denotes a heating member, 28 denotes a pressure roller, and P denotes a transfer material sheet.

 ─────────────────────────────────────────────────── (72) Inventor Kensaku Soka Kensaku Soka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hiroyuki Adachi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Co., Ltd. (56) References JP-A-59-157678 (JP, A)

Claims (1)

[Claims] 1. A heating body having a heating body that generates heat when energized, and a film having one surface sliding on the heating body and the other surface in contact with a recording material and moving together with the heating body. In a fixing device that heats and fixes an unfixed image on a recording material by heat from a recording medium, when stopping the fixing operation, the heating body may be de-energized during the movement of the film, and then the movement of the film may be stopped. Characterizing fixing device.