JPH087507B2 - Image heating fixing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to image heating incorporated 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. Regarding the fixing device.

More specifically, a recording material (electrofax sheet / electrostatic sheet) is used by using a developing material (hereinafter referred to as toner) made of a heat-meltable resin or the like by an appropriate image forming process means such as electrophotography, electrostatic recording, and magnetic recording. The unfixed visible image (hereinafter referred to as toner image) corresponding to the target image information is formed and carried on the surface of the recording sheet, the transfer material sheet, the printing paper, etc. by the direct method or the indirect (transfer) method, and the unfixed image is carried. The present invention relates to an image heating and fixing device in an image forming apparatus that heats and fixes the toner image as a permanently fixed image on the surface of a recording material carrying the image.

(Prior Art) Conventionally, as a heat fixing type image fixing device, an unfixed toner is composed of a heating roller maintained at a predetermined temperature and a pressure roller having an elastic layer in pressure contact with the heating roller. A roller fixing method in which a recording material on which an 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, each of the above-mentioned conventional fixing methods 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 an image heating and fixing device which has a small temperature rise in the machine and has other remarkable features.

(Means for Solving Problems) The present invention relates to a heating element, an endless fixing film in which one surface slides on the heating element and the other surface moves in contact with a recording material, and the fixing film. It has a suspension member around which the film is suspended, and a pressure member that forms a nip with the heating body through the fixing film, and sandwiches and conveys a recording material carrying an unfixed image at the nip, and through the fixing film. In the image heat fixing device for heating and fixing the unfixed image on the recording material by the heat from the heating body, the position of the suspending member is set so that the position in the direction orthogonal to the moving direction of the fixing film is within a predetermined range. An image heating and fixing device characterized in that it has a displacement means for changing the displacement means, and the displacement means operates when the pressure contact force between the heating body and the pressure member is released.

(Operation) (1) The recording material to be image-fixed, which is introduced between the fixing film and the pressing member, which is driven and driven in the same direction at the same speed as the conveyed recording material, is the unfixed toner (visible toner) on the surface of the fixing film. (Image material) The surface on the image bearing side is in close contact with the fixing film and overlaps with the fixing film. , Pass through in close contact with each other without wrinkling.

In the process of passing through this fixing nip portion, the unfixed toner image on the recording material surface is heated and softened by the heating body through the fixing film.
The toner is melted, and in particular, the surface layer portion thereof largely exceeds the melting point of the toner and is completely softened and melted (high temperature melting). In this case, the heating element, the fixing film, the toner image, and the recording material are satisfactorily pressed and adhered by the pressing member in the fixing nip portion, and the heat is effectively transferred, so that the toner is sufficiently softened and melted by heating for a short time. As a result, good fixability can be 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.

Then, the recording material and the fixing film which are in close contact with each other and have been heated by passing through the fixing nip portion are separated from each other by the recording material passing through the fixing nip portion and being heated and fixed. The recording material and the fixing film are separated from each other while the temperature is still higher than the glass transition point of the toner. Alternatively, after passing through the fixing nip part, the recording material is conveyed while being in close contact with the fixing film for a while, and the cooling process (natural cooling / forced cooling) is performed during that time.
As the toner image is cooled and solidified, the recording material and the fixing film are separated from each other.

In the case of, the toner still at a temperature higher than the glass transition point at the time of separation has an appropriate rubber property, so the toner image surface at the time of separation does not follow the surface of the fixing film and has an appropriate uneven surface property. Since the surface of the toner image is cooled and solidified while its surface property is maintained, excessive toner image gloss does not occur on the fixed toner image surface. Also, while the heat-fixed toner image is still at a temperature higher than the glass transition point, the bonding strength (adhesion) between the toner image surface and the fixing film surface in a close contact state is equal to or lower than the glass transition point when the toner image is adhered to the fixing film surface. It is smaller than the bonding force between the surface of the solidified toner image and the surface of the fixing film which have been cooled and solidified. Therefore, toner offset to the surface of the fixing film hardly occurs in the process of separating the recording material and the fixing film, and the recording material and the fixing film at the separating position have good separability. The risk of jamming and jamming is also eliminated.

While the heat-fixed toner image is still at a temperature higher than the glass transition point, the heat-fixed toner image of the recording material separated from the surface of the fixing film has a glass transition point while the separated recording material is transported to the discharge portion. Then, it is cooled (natural cooling, or forced cooling means using air blowing, heat radiation fins, or the like may be used) to be solidified and output to the discharge part.

In the above case, the toner image is cooled and solidified by the cooling process before separation, so that the toner cohesive force becomes very large and the particles behave as a group, and the adhesiveness / adhesion force to the recording material side increases. On the other hand, that for the fixing film side is extremely decreased. For the recording material, the toner is pressed by the pressing member when it is heated and softened / melted in the fixing nip portion which is the heating step portion, so at least a part of the toner image penetrates into the recording material surface layer, The adhesive effect of the solidified toner on the recording material side is increased due to the anchoring effect of the solidified material by cooling and solidification. Therefore, at the time of separation of the recording material and the fixing film, the toner image has a sufficiently large adhesiveness / adhesion force to the recording material due to cooling and solidification, and that to the fixing film is extremely small.
The recording material portion on which the image has been fixed is easily and sequentially separated without causing toner offset with respect to the fixing film, and then output to the discharge portion.

In this way, a toner image that does not cause toner offset or recording material separation defects / wrapping with respect to the fixing film is used, and the toner image is heated and fixed with a simple configuration by supplying power to the heating element. The toner image can be efficiently heated by maintaining the heating body at a temperature sufficiently high for the temperature (melting point or softening point) at which the toner should be heated for fixing. As a result, it is possible to perform sufficiently good fixing without defective fixing with a small amount of energy, and as a result, it is possible to obtain an image forming apparatus that has a small standby time during use of the apparatus, power consumption, and a small temperature rise inside the apparatus.

(2) In the present invention, the fixing film is of the endless rotating belt type so that it can be repeatedly used for fixing processing over a long period of time.

However, one of the problems when the fixing film is made into an endless rotating belt type is that the endless fixing film is lengthened on the front side or the back side in the width direction due to the repeated rotation of the fixing film. It is easy to cause a phenomenon of moving naturally along the line.

If such deviation occurs excessively, the fixing film may be wrinkled or damaged, or the recording material may have a portion in direct contact with the heating element, causing the toner as the image material to be offset at high temperature on the heating element surface, As a result, the material may be burnt or the recording material may be skewed to cause blurring or bending of the fixed image.

In the present invention, since the endless rotating belt type fixing film is provided with the deviation control means for automatically correcting the deviation toward the front side or the back side in the width direction, the above problems can be solved.

If the deviation control means executes the deviation control when the recording material is passed through the apparatus, a shock of control ON causes image blurring in the image fixing unit or the image forming unit or both parts, or the sheet is passed. There is a risk that the recording material will skew as the film shift is controlled.

Also, when the fixing film is controlled in a state in which the heating member and the pressure member are in pressure contact with the fixing film sandwiched in the fixing nip portion with a strong pressing force required for fixing, when the deviation of the fixing film is controlled, the vibration / Distortion is concentrated on the fixing film due to impact, and the film is likely to be broken, resulting in damage such as wrinkles.

In the present invention, the deviation control by the deviation control means is performed when the fixing film is rotating and the recording material does not exist in the fixing nip portion and the pressure contact force between the heating body and the pressure member is caused by the releasing or reducing means. The fixing film is executed in a released or reduced state, whereby the problems as described above are solved, the fixing film is protected from damage, and the life can be extended.

In addition, by turning off the power supply to the heating element during the deviation control, the heating element abnormally rises due to the change in the heat radiation characteristic of the heating element due to the release or reduction of the pressure contact force between the heating element and the pressure roller. The temperature phenomenon can be prevented.

(Embodiment) FIG. 5 shows a schematic configuration of an example of an image forming apparatus incorporating the image heating and fixing device 11 according to the present invention. The image forming apparatus of this example is a reciprocating platen / rotating drum type / transfer type electrophotographic copying apparatus.

(1) Overall Schematic Configuration of Copying Device In FIG. 5, 100 is a machine casing, 1 is a reciprocating original document mount made of a transparent plate member such as a glass plate disposed on a top plate 100a of the machine casing. It is a stand, and is reciprocatingly driven on the machine casing top plate 100a to the right a and the left a'in the drawing at predetermined speeds.

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 leading edge of the image forming portion reaches the portion of the transfer discharger 8, the leading edge of the transfer material sheet P also reaches the position between the transfer discharger 8 and the photosensitive drum 3 and is timed and synchronized so as to coincide with each other. Be delivered. Then, the transfer discharger 8 is attached to the surface of the fed sheet.
Thus, the toner images on the photosensitive drum 3 side are sequentially transferred.

The sheet to which the toner image has been transferred in the transfer unit is sequentially separated from the surface of the photosensitive drum 3 by a separation unit (not shown),
The unfixed toner image carried to the fixing device 11 to be described later by 10 is subjected to heat fixing processing, and passes through the guide 35 and the discharge roller 36 as an image-formed product (copy) and is discharged onto the discharge tray 12 outside the machine. Is discharged to.

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 11 FIG. 1 is an enlarged view of the fixing device 11 portion.

Reference numeral 25 denotes an endless belt-shaped fixing film, which has a left driving roller 26, a right driven roller 27, and a low heat capacity linear member as a heating member fixedly supported below both rollers 26 and 27. The heating member 20 and the guide roller 26a disposed below the driving roller 26, the four members 26.2 parallel to each other.
Suspended between 7/20 / 26a.

The driven roller 27 is an endless belt-shaped fixing film 25.
The fixing film
A transfer material sheet P 25 has a predetermined peripheral speed in the clockwise direction with the clockwise rotation of the driving roller 26, that is, an unfixed toner image Ta conveyed from the image forming portion 8 side, which is carried on the upper surface.
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 with good releasability, such as silicon rubber, as a pressure member, and sandwiches the film portion on the descending side of the endless belt-shaped fixing film 25 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 25 driven to rotate
Since the toner is repeatedly used for heat fixing of the toner image, it has excellent heat resistance, releasability and durability, and is generally 100 μm or less, preferably 50 μm or less. For example, a single-layer film of a heat-resistant resin such as polyimide, polyetherimide, PES, or PFA (tetrafluoroethylene-perfluoroalkylvinyl ether copolymer resin) or a composite layer film, for example, at least the image contact surface side of a 20 μm thick film And a 10 μm-thick release coating layer obtained by adding a conductive material to a fluororesin such as PTFE (tetrafluoroethylene resin) and PAF.

The low-heat-capacity linear heating element 20 as a heating element according to the present example has a horizontally long rigidity, high heat resistance, and heat insulating property whose longitudinal direction is the transverse direction of the fixing film (the direction perpendicular to the running direction of the fixing film 25). A heater support 24, and a heating element 22 which is integrally attached to and held on the lower surface side of the support along the length of the lower surface.
It comprises a heater substrate 21 having a temperature measuring element 23 and the like.

The heater support 24 secures the overall strength of the heating body 20, and is, for example, PPS (polyphenylene sulfide), PAI
(Polyamideimide), PI (polyimide), PEEK (polyether ether ketone), high heat resistant resin such as liquid crystal polymer, or a composite material of these resins and ceramic metal, glass or the like.

The heater substrate 21 has a thickness of 1.0 mm, a width of 10 mm, and a length of 2 as an example.
It is a 40 mm alumina substrate, and the heating element 22 is a substrate as an example.
A linear or belt-like low-heat-capacity current-generating heating element formed by applying an electric resistance material such as Ta ₂ N to a width of 1.0 mm (screen printing or the like) along the length substantially in the center of the lower surface of 21. The temperature measuring element 23 is, for example, an upper surface of the substrate 21 (a heating element).
This is a low-heat-capacity resistance thermometer, such as a Pt film, provided by coating (screen printing, etc.) along the length substantially at the center of the surface opposite to the side where 22 is provided.

In the case of the present example, the linear or belt-like heating element 22 is energized from both longitudinal ends thereof to generate heat over the entire length. Energization is a pulsed waveform with a cycle of 20 msec of DC 100 V, a desired temperature controlled by the temperature measuring element 23, and a pulse width corresponding to the amount of energy released is given to the energization control circuit configuration, and the pulse width is The heating element 22 is controlled within a range of approximately 0.5 to 5 msec, and the temperature of the heating element 22 is instantly raised to around 200 to 300 ° C. each time a pulse is input. Further, in this example, a sheet front and rear end detection sensor (not shown) is provided on the upstream side of the fixing device 11 in the transfer material sheet conveying direction, and the sheet detection signal of the sensor is used to energize the heating element 22. The period is controlled only to the required period in which the sheet P is passing through the fixing device 11.

(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 above-mentioned sensor (not shown) arranged nearer, rotation (or running) of the fixing film 25 is started,
The transfer material sheet P is guided by the guide 29, and the fixing sheet 25 at the pressure contact portion N (fixing nip portion) between the heating body 20 and the pressure roller 28.
Between the pressure roller 28 and the pressure roller 28, and the unfixed toner image surface comes into close contact with the lower surface of the fixing film 25 which is in the surface moving state in the same direction at the same speed as the conveyance speed of the sheet P to cause surface deviation or wrinkling. Without passing through the fixing film 24, the fixing film 24 passes through the fixing nip portion N between the heating body 20 and the pressure roller 28 while receiving a nipping pressure.

w is the width dimension of the heating element 22 provided on the lower surface of the heating element, and the heating element 22 is in the mutual pressure contact width area between the lower surface of the pressure element 20 and the upper surface of the pressure roller 28, that is, the fixing nip portion N. It exists in the width area.

The toner image bearing surface of the sheet P is a heating element in the process of passing through the fixing nip portion N while being pressed and closely attached to the fixing film surface.
The heat of 22 is received through the fixing film 24, and the toner image is melted at a high temperature and softened and adhered to the surface of the sheet P Tb.

In the case of the apparatus of this example, a recording material sheet P and a fixing film
The sheet P is separated from the sheet 24 when the sheet P passes through the fixing nip portion N and exits.

At the time of this separation, the temperature of the toner Tb is still higher than the glass transition point of the toner, and therefore the bonding force (adhesive force) between the sheet P and the fixing film 25 at the time of this separation.
Since the sheet P is small, the sheet P hardly causes toner offset to the surface of the fixing film 25, and the sheet P is always smoothly separated without being wound and jammed while being adhered to the surface of the fixing film 25 due to separation failure. Go.

And, since the toner Tb in a state of a temperature higher than the glass transition point has an appropriate rubber property, the toner image surface at the time of separation has an appropriate uneven surface property without following the fixing film surface, and this surface property is improved. Since the toner image is maintained and cooled and solidified, a proper image gloss is not generated on the fixed toner image surface, and high quality image is obtained.

The sheet P separated from the fixing film 25 is guided by the guide 35 and reaches the discharge roller pair 36. The temperature of the toner Tb higher than the glass transition point naturally lowers (natural cooling), and the temperature is lower than the glass transition point. Then, the solidified Tc is reached, and the sheet P on which the image has been fixed is output onto the tray 12.

In the present embodiment, since the linear heating element 22 of the heating element 20 is instantaneously heated to a sufficiently high temperature relative to the melting point (or fixable temperature) of the toner by energization, it is not necessary to preheat the heating element. The heat transfer to the pressure roller 28 during non-fixing is small. Also during fixing, fixing film, toner image,
Since the sheet is interposed in the fixing nip portion N between the heating body 20 and the pressure roller 28 and the heat generation time is short, a sharp temperature gradient is generated. The temperature is maintained below the melting point of the toner even when continuous image formation is performed to the extent required. In the apparatus of this embodiment having such a structure, 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 25, and in particular, the surface layer portion thereof is completely melted. It softens and melts. At this time, the heating roller, the fixing film, the toner image, and the sheet are in good contact with each other by the pressure roller 28, and the heat is efficiently transferred. As a result, 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 saving can be achieved by limiting the heating time for energization.

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

(4) Fixing Film Deflection Control Means 51 and 52 in FIG. 1 and FIG. 2 are first and second film position detecting means arranged at two positions on the front side and the back side of the fixing film in the width direction. For example, it is a photo interrupter / photo reflector or the like.

When the film 25 moves toward the front side as a whole along the length of the driving roller 26, the driven roller 27, the heating body 20, and the guide roller 26a, which are suspension tension members, and the deviation exceeds the allowance, the film 25 The edge portion 25a on the front side of is detected by the first film position detecting means 51 and is input to the control circuit. On the other hand, when the film 25 is excessively shifted to the back side B, the back side edge portion 25b of the film is detected by the second film position detection means 52 and is input to the control circuit.

Reference numeral 53 is a deviation control mechanism of the fixing film 25. The mechanism of this embodiment is a mechanism for horizontally moving the bearing 27a on the front side of the driven roller 27 in the left and right directions, ie, the direction X closer to the drive roller 26 and the direction Y away from it.

That is, in general, the belt-like material has a property of moving toward a narrow direction between the shafts around which the suspension is stretched, and the deviation control mechanism of this example uses this, and the bearing on the front side of the driven roller 27 is used.
When 27a is moved in the direction X closer to the drive roller 26, the fixing film 25 moves toward the front side A as a whole, and when it is moved away from the drive roller 26 in the direction Y, the fixing film 25a is moved.
25 moves B toward the back as a whole.

When the film detection signal of the first film position detecting means 51 is input to the control circuit, the deviation control mechanism controls the movement of the bearing 27a on the front side of the driven roller 27 in the Y direction, thereby fixing the film 25. When the film shift signal of the second film position detection means 52 is input to the control circuit by correcting the deviation toward the front side of the fixing film 25, the bearing 27a is controlled to move in the X direction, and The bias toward the side is corrected.

The deviation control mechanism 53 is always kept in the deviation control prohibited state. Reference numeral 60 denotes a means mechanism for releasing or reducing the pressure contact force between the heating body 20 and the pressure roller 28. The mechanism 60 of this example operates according to a control signal to move the pressure roller 28 to the heating body 20.
On the other hand, an unillustrated urging means that presses with a strong pressing force necessary for fixing is pulled away from the heating body 20 against the urging force to move the pressing force to a released state or a reduced state. , For example, an electromagnetic solenoid.

FIG. 3 is a sequence flow diagram of a deviation control example. That is, the image forming apparatus detects the pre-rotation, the paper interval, and the post-rotation in the image forming operation cycle by a paper feed sensor, a paper ejection sensor, and the like (not shown), and only at that time, the control prohibition of the deviation control mechanism is released to shift the deviation. Put in controllable state. The leaning control may be prohibited by software such as a microcomputer or mechanically.

When the shift control is started and the shift of the film is detected, the pressure of the pressure roller 28 is first released, and then the shift control is performed to perform the re-pressing. Then, the image forming process or the image forming apparatus stopping process is started.

By controlling in this manner, a good image can be obtained and damage to the fixing film can be reduced, so that the life of the fixing device or the image forming apparatus can be remarkably extended.

In the above-described embodiment, the pressure release is performed after the deviation of the fixing film 25 is detected. However, the pressure release is immediately performed after the absence of the sheet P in the fixing nip portion N is detected, and the deviation control is performed thereafter. May be.

By directly releasing the pressure, the pressure contact time of the fixing film 25 to the heating body 20 is shortened, so that the amount of wear of the fixing film 25 and the heating body 20 can be reduced, and the effect of extending the life can be achieved. is there.

Further, in the above-described embodiment, the temperature control of the heating body 20 is continued even when the pressure is released, but it is also preferable to turn off the power supply to the heating body 20. The sequence flow in that case is shown in FIG. After the deviation is detected and before the pressure is released, the power supply to the heating body 20 is turned off, and the pressure release, the deviation control, the re-pressurization, and the reheating are continued.

By turning off the power supply to the heating body 20 when the pressure is released, it is possible to prevent the abnormal temperature rise of the heating body 20 due to the change in the heat radiation characteristics of the heating body 20 due to the release of the pressure member 28 due to the release of the pressure. preferable.

(5) Others The deviation control mechanism 53 moves both ends of the front end and the rear end of the driven roller 27 in a direction approaching the drive roller 26 and a direction separating from the drive roller 26, respectively. The fixing film by making the front side and the back side of the roller different.
25 offset control can be performed or driven roller
The front end and the rear end of 27 are arranged in the vertical direction C / D (first
It is also possible to control the deviation of the fixing film by moving the fixing film to the position shown in FIG. For example, by setting the back side to a relatively high position, the fixing film 25 starts to move toward the back side. Other shift control mechanisms such as moving the driven roller 27 to the twisted position may be adopted.

Regarding the heating element 20, the substrate 21 can be made of heat-resistant glass, heat-resistant resin such as PI / PPS, or the like in addition to alumina. As the heating element 22, other than Ta ₂ N, a resistor such as nichrome, RuO ₂ , Ag / Pd or the like can be used. As the temperature detecting element 23, a bead thermistor having a resistance capacity can be used in addition to a temperature measuring resistor such as a Pt film. It is preferable to provide a sliding protective film layer such as a thin heat-resistant glass layer on the lower surface of the heating body on which the fixing film 25 slides and travels. The heating element 22 is disposed on the upper surface side of the substrate 21 (the surface of the substrate 21 opposite to the fixing film facing surface), and the temperature measuring element 23
May be disposed on the lower surface side of the substrate 21 (the surface facing the fixing film of the substrate 21), or both the heating element 22 and the temperature measuring element 23 may be disposed on the lower surface side of the substrate 21. Heating element
The energization to 22 may be normal AC energization control instead of pulse energization.

A felt pad is provided for cleaning the film surface, and a slight release agent, for example, silicone oil is impregnated to bring the pad into contact with the film surface to further clean the film surface and further improve the releasability. You may 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, conductive powder fibers such as carbon black are added to the fluororesin,
One measure is to prevent the image disturbance due to the static electricity described above. 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.

The fixing film can be easily attached and detached to a predetermined portion of the fixing device 11 to facilitate replacement of the fixing film.

As described above, the fixing device of the present invention is not limited to the transfer type electrophotographic device illustrated in FIG. 5, and the image forming process / means is a direct type in which a toner image is directly formed and carried on electrofax paper, electrostatic recording paper, or the like. Copiers, laser beam printers, facsimiles, microfilm reader printers that use a magnetic recording image forming system or other suitable image forming process / means to form an image with heat-melting toner on a recording material and heat-fix it. The present invention can be effectively applied as an image heating and fixing device in various image forming apparatuses such as a display device and a recording machine.

(Effects of the Invention) As described above, the image heating and fixing device of the present invention uses a small and simple heating means having a small heat capacity to heat an image with good heat efficiency and with a small amount of energy, fixing failure, offset, and jamming jamming of recording material. The image can be fixed well enough without causing problems such as standby time and power consumption when using the device, and the temperature rise inside the machine is small.By properly controlling the film deviation, the deviation of the fixing film can be prevented. It is possible to prevent wrinkles and breakage of the fixing film to extend the life of the film, and to prevent toner from adhering to the heating element, and to prevent blurring of the image and skew of the paper, and to achieve a good fixed image. Can be output, and is practical as an image heating and fixing device that does not have the above-mentioned problems of the conventional device, and the intended purpose can be achieved well.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a fixing device according to a first embodiment, FIG. 2 is a plan view thereof, FIGS. 3 and 4 are sequence control flow charts of film deviation control, respectively, and FIG. 5 shows the fixing device. FIG. 3 is a schematic configuration diagram of an example of an incorporated image forming apparatus. 11 is the whole number of the fixing device, 20 is a heating element, 25 is a fixing film, 28 is a pressure roller, P is a sheet, Ta is an unfixed toner,
Tb is a heat-softened / melted toner, Tc is a solidified toner, N is a fixing nip portion, and 51/52/53 are film deviation control means mechanisms.

Claims (1)

[Claims] 1. A heating member, an endless fixing film having one surface sliding on the heating member and the other surface contacting a recording material and moving together, and a suspending member around which the fixing film is suspended. And a pressure member that forms a nip with a heating body via a fixing film, and the recording material carrying an unfixed image is nipped and conveyed in the nip, and unfixed by heat from the heating body via the fixing film. An image heating and fixing device for heating and fixing an image on a recording material has a displacement means for changing the position of the suspension member so that the position in the direction orthogonal to the moving direction of the fixing film is within a predetermined range. The image heating fixing device is characterized in that the means operates when the pressure contact force between the heating member and the pressure member is released.