JPH02157880A - Image heat fixing device - Google Patents

Abstract

PURPOSE:To prevent the wrinkle or the breakage of a fixing film, to eliminate the blurring of an image and to perform excellent fixing by providing an offset control mechanism on the fixing film in a fixing device and performing the control of offset when paper is not allowed to pass. CONSTITUTION:On the front side and the back side of the fixing film 25 in the fixing device 11, film position detecting means 51 and 52 such as a photointerrupter, etc., are provided and the bearing 27a of a follower roller 27 is provided in X and Y directions so that it can horizontally move. When the detecting means 51 on the front side is actuated in a state where the film 25 is turned and the recording paper is not allowed to pass, the detection signal from the means 51 is inputted in a control mechanism 53, so that the bearing 27a is moved in the Y direction and the offset to the front side is corrected. When the offset to the back side occurs, the bearing 27a is moved in the X direction with the detection signal from the detecting means 52 in the same way. Therefore, the offset of the film 25 is prevented and the paper is kept from obliquely advancing, thereby performing the excellent fixing.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to an image heating system that is incorporated into image forming apparatuses such as copying machines, laser beam printers, facsimile machines, microfilm reader printers, image display devices, and recording machines. Regarding a fixing device.

More specifically, a recording material (electrofax sheet, electrostatic Direct method or indirect (transfer) to the surface of recording sheet, transfer material sheet, printing paper, etc.
A method is used to form and carry an unfixed visual image (hereinafter referred to as a toner image) corresponding to the target image information, and heat and fix the unfixed toner image as a permanently fixed image on the surface of the recording material carrying the image. The present invention relates to an image forming apparatus that processes images.

(Prior Art) Conventionally, a heat fixing type image fixing device uses a heating roller maintained at a predetermined temperature and a pressure roller having an elastic layer that presses against the heating roller to fix unfixed toner. A roller fixing method is often used in which a recording material on which an image is formed is heated while being nipped and conveyed.

Belt fusing systems are also known, such as those disclosed in U.S. Pat. No. 3,578,797. This is done by: (1) Bringing the toner image into contact with a heating body web and heating it to its melting point to melt it; (2) After melting, the toner is cooled to a relatively high viscosity; (2) The toner image is heated while reducing its tendency to stick. By peeling it off from the body web, it is fixed without causing any offset.

(Problems to be Solved by the Invention) However, all of the above conventional fixing systems have the following problems.

Heat roll fixing method ■It takes a considerable amount of time to reach a predetermined temperature, during which time image formation is prohibited. That is, there is a so-called wait time.

■Because it requires heat capacity, a large amount of electric power is required.

■A special heat-resistant bearing is required because the roller temperature is high for rotating rollers.

■The rollers are in direct contact with the hands, which may be dangerous and require protective materials.

■Due to the roller's constant temperature and curvature, the recording material wraps around the roller and the recording material jams. This makes it easy to see the trouble.

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

The present invention solves the above-mentioned problems of the conventional apparatus, and makes it possible to reduce the heat capacity of the heating element without causing fixing failure or offset, thereby reducing standby time, power consumption, and It is an object of the present invention to provide an image heat fixing device that causes a small temperature rise inside the machine and has other remarkable features.

(Means for Solving the Problems) The present invention provides an endless belt-like fixing film that is suspended between tension members and is rotationally driven, and a fixing film that is attached to one side of the fixing film with the fixing film inside. a heating member arranged on the other side, and a pressure member arranged opposite to the heating member on the other side and bringing the image bearing surface of the recording material to which the image is to be fixed into close contact with the heating member via the fixing film. At least when performing image fixing, the fixing film is rotatably run at the same speed in the forward direction as the recording material to which the image is to be fixed, which is conveyed and introduced between the fixing film and the pressure member. By passing the recording material and the recording material in close contact with each other through a fixing nip formed by pressure contact between the heating body and the pressure member, the image bearing surface of the recording material is transferred through the fixing film. The fixing film is heated by a heating body to heat and fix the visible image, and has a deviation control means for automatically correcting deviation of the rotatably driven endless belt-shaped fixing film toward the front side or the back side in the width direction. The image heat fixing device is characterized in that the shift control is executed when no recording material passes through the device.

Furthermore, during the pre-rotation period during which the image forming apparatus does not pass the recording material to the apparatus during the image forming cycle, the deviation control described above is performed.
The image heat fixing apparatus is characterized in that it is executed during a post-rotation period, during a gap between recording materials that are sequentially passed, or during a combination thereof.

(Function) (1) The recording material to which the image is to be fixed is introduced between the fixing film and the pressure member, which are driven to run in the same direction at the same speed as the conveyed recording material. (Art materials) When the image-bearing side is in close contact with the fixing film and is overlapped with the fixing film, the mutual pressure contact area (fixing nip area) between the heating body and the pressure member is subjected to squeezing pressure, and the surfaces may become misaligned due to the speed difference. , they overlap and pass together in close contact with each other without wrinkles.

During this process of passing through the fixing nip, the unfixed toner image on the surface of the recording material is heated and softened and melted by the heating body via the fixing film, and in particular, the surface layer exceeds the toner melting point and is completely softened and melted (high temperature melting). do. In this case, the heating body, fixing film, toner image, and recording material are pressed tightly together by the pressure member in the fixing nip and heat is transferred effectively, so that the toner is sufficiently softened and melted by heating for a short time. to obtain good fixing properties. On the other hand, the temperature rise of the recording material itself is actually extremely small and there is little waste of thermal energy. In other words, the recording material itself is not heated substantially, only the toner is effectively heated to soften and melt, and the toner image can be successfully heat-fixed with low power.

Separation of the recording material and fixing film, which are in close contact with each other and heated after passing through the fixing nip, is as follows: The recording material and the fixing film are separated from each other while the temperature of the painting material is still higher than the glass transition point of the toner. Alternatively, the recording material is conveyed while remaining in close contact with the fixing film for a while after passing through the fixing nip, and the toner image is cooled and solidified during the cooling process (natural cooling/forced cooling). and the fixing film are separated from each other.

In the case of (2), the toner, which is still at a temperature higher than the glass transition point at the time of separation, has appropriate rubber characteristics, so the toner image surface at the time of separation does not follow the surface of the fixing film and has an appropriate unevenness. Since the toner is cooled and solidified while its surface properties are maintained, excessive image gloss does not occur on the fixed toner image surface. Furthermore, while the heat-fixed toner image is still at a temperature higher than the glass transition point, the bonding force (adhesive force) between the toner image surface and the fixing film surface in close contact with the fixing film surface is below the glass transition point. This is smaller than the bonding force between the surface of the solidified toner image and the surface of the fixing film that has been cooled to a solidified state. Therefore, toner offset to the fixing film surface does not occur during the mutual separation process of the recording material and the fixing film, and the separation of the recording material and the fixing film at the separation position is also good. There is also no possibility of the recording material becoming entangled and causing a jam problem.

While the heat-fixed toner image is still at a temperature higher than the glass transition point, the heat-fixed toner image on the recording material separated from the fixing film surface reaches the glass transition point while the separated recording material is transported to the discharge section. Thereafter, it is cooled (natural cooling, or forced cooling means such as air blowing or heat radiation fins may be used) to solidify and output to the discharge section.

In the case of (2) above, the cohesive force of the toner becomes extremely large due to the cooling and solidification of the toner image caused by the cooling process of the bait to be separated, and the toner behaves as a group. As it increases, it becomes extremely lower on the fixing film side. For the recording material, when the toner is heated and softened and melted in the fixing nip section, which is the heating process section, it is pressed by a pressure member, so at least a part of the toner image penetrates into the surface layer of the recording material. The anchoring effect caused by the cooling and solidification of the permeation valve increases the adhesion and adhesion of the cooled assimilated toner to the recording material side. Therefore, at the time when the recording material and fixing film are separated, the toner image is cooled and solidified, and the adhesion and adhesion force to the recording material is sufficiently large, but the adhesion and adhesion force to the fixing film is extremely small, so the part of the recording material where the image has been fixed is fixed. It is easily separated in sequence without causing toner offset to the film, and then output to the discharge section.

In this way, toner images can be heated and fixed without causing toner offset with respect to the fixing film, poor separation or wrapping of the recording material, and by using a heating element with a small heat capacity and with a simple configuration for power supply to the heating element. By maintaining a heating element at a temperature sufficiently high compared to the temperature (melting point or softening point) at which the toner should be heated in order to fix it, it is possible to efficiently heat the toner image. Therefore, sufficiently good fixing without defective fixing is possible with less energy, and as a result, it is possible to obtain an image forming apparatus with less standby time during use, less power consumption, and less internal temperature rise.

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

One of the problems when using an endless rotating belt type fixing film is that due to repeated rotation, the endless fixing film is stretched on the 1111 side or the back side in the width direction. A phenomenon in which the member naturally shifts along the length of the member tends to occur.

If such shifting occurs excessively, it may cause wrinkles or damage to the fixing film, or a portion of the recording material may come into direct contact with the heating element, causing high-temperature offset of the toner, which is the developing material, on the surface of the heating element, or recording This results in scorching of the material or skewing of the recording material.

In the present invention, since the endless fibrillation belt type fixing film is provided with a shift control means for automatically correcting the shift toward the front side or the back side in the width direction, the above-mentioned problem can be solved.

If the offset control by the offset control means is executed when the recording material is passed through the device, the shock of turning on the control may cause image blurring in the image fixing section, the image forming section, or both, or the paper may be unsteady as the paper passes through the device. There is a possibility that the recording material may be skewed due to the film shift control.

In the present invention, the shift control by the shift control means is performed when the recording material is not passing through the apparatus, for example, during the pre-rotation period or the post-rotation period of the image forming cycle, or when the recording material and the recording material are sequentially passed. The execution is performed during the period between the two or a combination of these, thereby solving the above-mentioned problems.

By controlling the shift when paper is not passing in this way, the fixing film is prevented from shifting, and wrinkles and
Damage is prevented, toner does not adhere to the heater, image blurring and paper skewing are also prevented, and good image fixation can be achieved.

(Embodiment) FIG. 8 shows a schematic configuration of an example of an image forming apparatus incorporating an image heat fixing device 11 according to the present invention. The image forming apparatus of this example is an electrophotographic copying apparatus of a reciprocating document table type, a rotating tram type, and a transfer type.

(1) Overall schematic structure of the copying machine On the right side of FIG. This is a document mounting table, and is driven to reciprocate at a predetermined speed on the top plate 100a of the machine casing in the right direction a and the left direction a in the drawing, respectively.

G is an original, and it is placed on the original mounting table IQ) and lz surface according to a predetermined placement standard with the image surface fil to be copied facing downward, and the original pressing plate 1a is placed on top of it and pressed down. Set.

Reference numeral 100b denotes a slit opening as a document illumination section, which is opened on the surface of the top plate 1008 of the machine casing, with its length extending in a direction perpendicular to the direction of reciprocating movement of the document table 1 (direction perpendicular to the plane of the paper). The downward image surface of the document G set on the document platform 1 passes through the position of the slit opening 100b sequentially from the right side to the left side during the forward movement of the document platform 1 to the right side a. In the process of passing through, the light of lamp 7 enters the slit opening! 00b, the document is received through the transparent document table 1 and scanned by illumination. The light reflected from the document surface of the illumination scanning light is imaged and exposed on the surface of the photosensitive drum 3 by the short focus and small diameter imaging element array 2.

The photosensitive drum 3 is coated with a photosensitive layer such as an oxide (81) photosensitive layer or an organic semiconductor photosensitive layer, and is driven to rotate clockwise as shown by an arrow around a central support shaft 3a at a predetermined circumferential speed. The photosensitive drum 3 is charged with positive or negative polarity by the charger 4, and the charged surface is subjected to imaging exposure (slit exposure) of the N-striped image.
Electrostatic latent images corresponding to the image-formed and exposed original image are sequentially formed on the surface.

This electrostatic latent image is sequentially visualized by a developing device 5 using toner made of a resin or the like that softens and melts when heated, and the developed toner image is transferred to a location where a transfer discharger 8 is provided as a transfer section. I will do it.

S is a cassette loaded with transfer material sheets P as recording materials, and the sheets in the cassette are fed one by one by the rotation of the feeding roller 6, and then the toner on the drum 3 is transferred by the registration roller 9. The timing is set so that when the leading edge of the image forming section reaches the position of the transfer discharger 8, the leading edge of the transfer material sheet P also reaches the open position of the transfer discharger 8 and the photosensitive tram 3, so that they are aligned. Feeds synchronously. Then, the toner image on the photosensitive drum 3 side is sequentially transferred onto the surface of the fed sheet by the transfer discharger 8.

The sheet to which the toner image has been transferred in the transfer section is sequentially separated from the three surfaces of the photosensitive drum by a separating means (not shown) and transferred to the conveying device 1.
0, the unfixed toner image carried thereon is guided to a fixing device 11 (described later) to be heated and fixed, and then passed through a guide 35 and an ejection roller 36 as an image-formed product (copy) onto a paper ejection tray 12 outside the machine. is discharged.

On the other hand, after the toner image has been transferred, the photosensitive drum 3 is subjected to a cleaning device 13 to remove adhered stains such as residual toner after transfer, and is used repeatedly for image formation.

(2) Fixing device 11 FIG. 1 is an enlarged view of the fixing device 11 portion.

Reference numeral 25 designates an endless belt-shaped fixing film, which includes a driving roller 26 on the left side, a driven roller 27 on the right side, and a low heat capacity linear film as a heating element fixedly supported and disposed below between both rollers 26 and 27. Heating body 20, drive roller 26
The guide roller 26a is disposed below the guide roller 26a, and is suspended between the four members 26, 27, 20, and 26a that are parallel to each other.

The driven roller 27 is an endless belt-shaped fixing film 2.
The fixing film 25 is fixed clockwise at a predetermined circumferential speed as the drive roller 26 rotates in the clockwise direction, that is, the unfixed toner image Ta conveyed from the image forming section 8 side. wrinkles, meandering, etc. at the same peripheral speed as the conveyance speed of the transfer material sheet P carrying the
Rotation is driven without speed delay.

A pressure roller 28 serves as a pressure member and has a rubber elastic layer such as silicone rubber with good mold releasability. The lower surface is pressed against the lower surface by a biasing means (not shown) after applying a total pressure of, for example, 4 to 7 kg, and is rotated counterclockwise in the forward direction in the conveyance direction of the transfer material sheet P.

Endless belt-shaped fixing film 25 that is rotatably driven
Because it is used repeatedly to heat and fix toner images, it has excellent heat resistance, releasability, and durability, and has a thin wall of 100 μm or less, preferably 50 μm or less. For example, polyimide, polyetherimide, PES-PF
A (tetrafluoroethylene-perfluoroalkyl vinyl ether combination resin) or other heat-resistant resin single-layer film or composite layer film, such as a 20 μm thick film, at least on the image contacting side of PTFE (tetrafluoroethylene resin). ) - A releasable coating layer made of a fluororesin such as PAF with a conductive material added to a thickness of 0 μm.

The low heat capacity linear heating element 20 as a heating element in this example has rigidity, high heat resistance, and heat insulation properties in a horizontally long direction in which the longitudinal direction is the transverse direction of the fixing film (direction perpendicular to the running direction of the fixing film 25). The heater support body 24 has a heater support body 24, and a heater base plate 21, which is integrally attached to the lower surface of the support body along the length of the lower surface and is equipped with 11 heating elements 22, temperature measuring elements 23, etc. .

The heater support 24 ensures the overall strength of the heating body 20, and is made of highly heat-resistant material such as pps (polyphenylene sulfide), pAr (polyamideimide), PI (polyimide), PEEK (polyetheretherketone), liquid crystal polymer, etc. It can be composed of synthetic resins or composite materials of these resins and ceramics, metals, glass, etc.

As an example, the heater board 21 has a thickness of 1.0 mm and a width of 10 m.
It is an alumina substrate with a length of 240 mm, and a heating element 22.
As an example, an electrically resistive material such as Ta7N is placed approximately at the center of the lower surface of the substrate 21 along its length to a width of 1.0 mm.
It is a linear or strip-shaped current-carrying heating element with a low heat capacity that is coated (screen printing, etc.) on the substrate 21. It is a low heat capacity temperature measuring resistor such as a PT film, which is coated (by screen printing, etc.) along the longitudinal direction of the substantially central part of the surface.

In the case of this example, electricity is applied to the linear or band-shaped heating element 22 from both ends of its length to cause the heating element 22 to generate heat over its entire length. Power supply is DClooV cycle 20m
The energization control circuit is configured to give a pulse corresponding to the desired temperature and energy release amount controlled by the temperature detection element 23 by changing the pulse [1] with a pulse-like waveform of s e c, and the pulse width is approximately 0. The heating element 22 is controlled in the range of .5 to 5 m5ec, and the temperature of the heating element 22 is instantly raised to 200 to 300°C every time a pulse is applied manually. Further, in this example, the transfer material sheet conveyance direction flow 0-1 is lower than that of the fixing device 11.
A sensor (not shown) for detecting the leading and trailing edges of the sheet is provided near the fixing device of the sheet P, and the sheet detection signal from the sensor determines the period of electricity supply to the heating element 22 as long as the required period for the sheet P to pass through the fixing device 11. is controlled.

(3) Fixing execution operation The device performs an image forming operation in response to an image forming start signal, and the leading edge of the transfer material sheet P carrying the unfixed toner image Ta on its upper surface is conveyed from the transfer section 8 to the fixing device 11. When detected by the above-mentioned sensor (not shown) disposed near the fixing film 25, rotation (or running) of the fixing film 25 is started, and the transfer material sheet P is guided by the kite 29 and heated by the heating body 2.
The unfixed toner image surface enters between the fixing sheet 25 and the pressure roller 28 at the pressure contact part N (fixing nip) between the pressure roller 28 and the pressure roller 28, and the unfixed toner image surface is conveyed at the same speed and in the same direction as the sheet P. The pressing force is applied to the fixing nip N between the heating body 20 and the pressure roller 28 while the fixing film 24 is in close contact with the lower surface of the fixing film 25 which is in a surface-shifting state, and is overlapped with the fixing film 24 without causing surface displacement or wrinkles. I will pass while receiving it.

W is the middle dimension of the heating element 22 provided on the lower surface of the heating element, and the heating element 22 is within the area where the lower surface of the heating element 20 and the upper surface of the pressure roller 28 are in mutual pressure contact, that is, the width of the fixing nip N. Exists within the area.

The toner image bearing surface of the sheet P passes through the fixing nip N while being in tight contact with the fixing film surface.
2 through the fixing film 24, the toner image is melted at a high temperature and is softened and adhered to the surface of the sheet 82 Tb.

In the case of this example device, the sheet P which is the recording material and the fixing film 2
Separation from the sheet 4 is performed when the sheet P passes through the fixing nip N and comes out.

At this time of 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 this time of separation is small, so that the sheet P is attached to the fixing film 25. The toner offset to the 25th surface hardly occurs, and the sheet P is always smoothly separated without being stuck on the 25th surface of the fixing film due to poor separation and jammed.

Since the toner Tb at a temperature higher than the glass transition point has appropriate rubber characteristics, the toner image surface upon separation does not follow the fixing film surface but has an appropriate uneven surface. Since the toner is maintained and cooled to solidify, the fixed toner image surface does not have appropriate image gloss, resulting in high quality images.

While the sheet P separated from the fixing film 25 is guided by a guide 35 and reaches a pair of discharge rollers 36, the temperature of the toner Tb, which is higher than the glass transition point, naturally cools down (natural cooling) to a temperature below the glass transition point. and solidified Tc.
The sheet P on which the image has been fixed is output onto the tray 12.

In this embodiment, the linear heating element 22 of the heating element 20 is heated instantaneously to a high enough temperature relative to the melting point (or fixing temperature) of the toner when energized, so there is no need to preheat the heating element. , heat transfer to the pressure roller 28 during non-fixing is small. Also, during fixing, the fixing film, toner image, and sheet are present in the fixing nip N between the heating body 20 and the pressure roller 28, and a steep temperature gradient occurs due to the short heat generation time. The temperature of the pressure roller 28 does not easily rise, and its temperature is maintained below the melting point of the toner even when continuous image formation is performed to the extent required for practical use. In the apparatus of this embodiment having such a configuration, the toner image made of heated hostile toner on the sheet P is first transferred to the fixing film 2.
5 and is heated and melted by the heating body 20, and in particular, the surface layer portion thereof is completely softened and melted. At this time, 5 pressure roller 2
8, the heating body, fixing film, toner image, and sheet are brought into close contact with each other, and heat is efficiently transferred. Thereby, the heating of the sheet P itself can be suppressed as much as possible, and the toner image can be efficiently heated and melted, and in particular, energy saving can be achieved by limiting the time for energization and heat generation.

A small heating element is sufficient, so the heat capacity is small, and there is no need to raise the temperature of the heating element, so power consumption during non-image formation can be reduced, and temperature rise inside the machine can be prevented. become.

(4) Fixing film deviation control means In Figs. 1 and 2, 51 and 52 indicate the fixing film [IJ
First and second film position detection means are arranged at two positions, one on the direction hand ttFr side and the other on the back side. For example, it is a photo interrupter, a photo reflector, etc.

When the film 25 moves toward the front side as a whole along the lengths of the driving roller 26, driven roller 27, heating body 20, and guide roller 26a, which are suspended tension members, and the deviation exceeds the allowable value, the film 25 The edge 25a of 1 front 0!1 is detected by the first film position detection means 51, and this is manually input to the control circuit. On the other hand, when the film 25 moves excessively toward the back side, the edge 25b on the back side of the film
is detected by the second film position detecting means 52 and inputted to the control circuit.

53 is a shift control mechanism for the fixing film 25. The mechanism of this example is a means mechanism for horizontally moving the front bearing 27a of the driven roller 27 in the left and right directions in the direction X toward the drive roller 26 and the direction Y away from the drive roller 26.

In other words, belt-like objects generally have a tendency to shift in a narrow direction between the shafts around which they are suspended, and the shift control mechanism of this example takes advantage of this, by moving the bearing 27a on the front side of the driven roller 27. When the fixing film 25 is moved in the direction X toward the drive roller 26, the entire fixing film 25 moves toward the front side,
When the fixing film 25 is moved in the direction Y away from the drive roller 26, the entire fixing film 25 moves toward the back side B.

When the film detection signal of the first film position detection means 51 is inputted manually to the control circuit, the front bearing 27a of the driven roller 27 is controlled to move in the Y direction by the shift control mechanism, so that the fixing film 25 is controlled to move in the Y direction. When the film detection No. 171 of the second film position detection stage 1 52 is manually applied to the trlJ control circuit, the bearing 27a is controlled to move in the X direction to fix the film. This corrects the excessive deviation of the film 25 to the back side.

FIGS. 3 and 4 are timing charts and control sequences of examples of shifting control of the fixing film 25. FIG. That is, when an image forming signal is input manually, the main motor starts rotating, and at the same time or after that, the drive roller 26 is rotated and the heating element 20 is started.
(22) is energized and heated. After the main motor starts rotating, the first or second position detection means 51/5
2 detects the offset position of the fixing film 25, and when excessive offset is detected, the mechanism 53 immediately controls the offset in accordance with the detection signal.

After this control is completed, the transfer material sheet P enters the fixing device 11 and a fixing operation is performed.

Since the shift control is performed before the transfer material sheet P enters the fixing device 11, the vibration vibration of the fixing film 25 caused by the shift control operation is not transmitted to the transfer material sheet P, and the fixing film 25 is fixed. Since it is placed at a predetermined position during operation, a good image can be obtained.

When the fixing film 25 is in the proper position, the shift control is not performed and the fixing operation is directly started.

By carrying out the above control, the fixing film 25 is correctly held during the fixing operation, so that a good fixed image is obtained, and at the same time, the occurrence of wrinkles or the like in the fixing film due to deviation of the fixing film 25 is prevented.

In the above example, the shift control sequence was performed during the pre-rotation period of the image forming cycle, but it may of course be performed during the post-rotation period when paper is not being passed. A timing chart in such a case is shown in FIG. When controlling deviation during rear rotation, it is possible to shorten the front rotation time,
This has the effect of shortening the time for forming the first image.

Furthermore, when forming images on a plurality of sheets, control may be performed between sheets. A timing chart in such a case is shown in FIG. By performing one control between sheets, the fixing film shift control can be performed more frequently than when controlling during surface rotation or post-rotation, so it is possible to suppress the shift amount of the fixing film 25 to a small value, which is preferable.

Furthermore, as shown in Fig. 7, by combining surface rotation and paper spacing, or paper spacing and post-rotation, image formation can always be within a certain amount of displacement, whether in single mode or multi-sheet mode. This is more preferable since it can be suppressed.

In the above embodiments, a mechanism for changing the distance between the axes is adopted as the deviation control mechanism 53, but it is also possible to use other means for moving the five driven rollers 27 to the twisted position.

Further, it is preferable that the deviation is detected at the deviation control surface, but it may be performed either when paper is passing or when no paper is passing.

(5) Other heating elements 20 For the substrate 21, other than alumina, heat-resistant glass, heat-resistant resin such as PI-PPS, etc. can be used. The heating element 22 is made of nichrome/Ru in addition to Ta2N.
A resistor such as O2.Ag/Pd or the like may be used. As the temperature measuring element 23, in addition to a temperature measuring resistor such as a PT film, a resistive capacitor beat thermistor or the like can be used. The lower surface of the heating element on which the fixing film 25 slides is preferably provided with a sliding protective film layer such as a thin heat-resistant glass layer. heating element 2
2 is a configuration in which the temperature measuring element 23 is arranged on the upper surface side of the substrate 21 (on the side opposite to the side facing the fixing film of the substrate 21), and the temperature measuring element 23 is arranged on the lower surface side of the substrate 21 (on the side facing the fixing film of the substrate 2). Alternatively, both the heating element 22 and the temperature measuring element 23 may be arranged on the lower surface side of the substrate 21. heating element 22
The energization may also be carried out by normal AC energization control instead of pulse energization.

In addition to providing a felt bat for cleaning the film, the bat is impregnated with a slight release agent, such as silicone oil, and brought into contact with the film surface to further improve the cleaning of the film surface and the patternability. You may also do so. When the fixing film is treated with an insulating fluororesin, static electricity that disturbs the toner image is likely to be generated on the film, so it is a good idea to remove the static electricity using a grounded static eliminator brush. The film may be charged within a range that does not disturb the toner image by applying a bias voltage to the brush without being grounded. Furthermore, one measure is to add conductive powder fibers, such as carbon black, to the fluororesin to prevent the above-mentioned image disturbance caused by static electricity. Furthermore, the charge removal and conductivity of the pressure roller can be carried out by the same means. Furthermore, an antistatic agent or the like may be applied or added.

By configuring the fixing film as a cartridge that can be attached to and removed from a predetermined portion of the fixing device 11, replacement of the fixing film can be facilitated.

Hereinafter, the fixing device of the present invention is not limited to the transfer type electrophotographic device illustrated in FIG. Copying machines, laser beam printers, facsimile machines, and microfilm reader printers that form an image using heat-fusible toner on a recording material using a magnetic recording image forming method or other appropriate image forming process or means, and then heat and fix the image. - It can be effectively applied as an image heat fixing device in various image forming apparatuses such as display devices and recording machines.

(Effects of the Invention) As described above, the image heat fixing device of the present invention heats images thermally efficiently using a small and simple heating means with a small heat capacity, and can solve problems such as defective fixing, offset, and recording material jamming with less energy. It is possible to fix a sufficiently good image without causing problems such as the standby time and power consumption when the device is in use, and the temperature rise inside the machine is small.By controlling the shift when paper is not passing, the fixing film is prevented from shifting. is,
It has features such as preventing wrinkles and damage to the fixing film, preventing toner from adhering to the heating element, and outputting good fixed images without image blur or skewed paper. It is practical as an image heat fixing device that does not have the problem of redundancy as in conventional devices, and the intended purpose can be achieved well.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of the fixing device of the first embodiment, FIG. 2 is a plan view thereof, FIGS. 3 and 4 are timing charts and sequence control flow diagrams of an example of film deviation control, and FIGS. 5 to 7. The figures are other examples of timing charts, and FIG. 8 is a schematic diagram of an example of an image forming apparatus incorporating the fixing device. 11 is the overall code of the fixing device, 20 is the heating element, 25 is the fixing film, 28 is the pressure roller, P is the sheet, Ta is the unfixed toner, Tb is the heat-softened/melted toner, Tc is the solidified toner, N is the fixing nip 51, 52, and 53 are film shift control means mechanisms. N

Claims (2)

[Claims] (1) An endless belt-shaped fixing film that is suspended between tension members and driven to rotate, a heating body placed on one side of the fixing film with the fixing film inside, and a heating body placed on the other side of the fixing film. A pressure member is disposed opposite to the heating body and brings the image bearing surface of the recording material to which the image is to be fixed into close contact with the heating body through the fixing film, and the fixing film at least performs image fixing. At this time, the traveling fixing film and the introduced recording material are brought into close contact with each other by being rotated in the forward direction at the same speed as the recording material to which the image is to be fixed, which is conveyed and introduced between the fixing film and the pressure member. The image-bearing surface of the recording material is heated by the heating element through the fixing film by passing through a fixing nip formed by pressure contact between the heating element and the pressure member, thereby fixing the image by heating. The apparatus includes a shift control means for automatically correcting the shift of the rotatably driven endless belt-shaped fixing film toward the front side or the back side in the width direction. An image heating fixing device characterized in that the image heating fixing device is operated at times. (2) The deviation control described above is performed during the pre-rotation period or post-rotation period in which the recording material is not passed through the image forming apparatus during the image forming cycle, or during the recording material and the recording material that are sequentially passed. 2. The image heat fixing apparatus according to claim 1, wherein the image heating fixing apparatus is carried out during a paper interval between the two or a combination thereof.