JPH03289690A - Fixing device - Google Patents

Abstract

PURPOSE:To prevent toner from being offset to the surface of a fixing film by an easy and inexpensive means for a long period by providing a separating agent supply means which applies and supplies a separating agent to the surface of the fixing film on a recording material contacting side or cleaning means and constituting those means as rotary bodies. CONSTITUTION:An oil coating roller 13 as the separating agent supply means is provided while pressed against the surface of the fixing film so that the fixing film 7 is clamped between the roller 13 and a fixing film driving roller 8 at the position of the driving roller 8; and the oil coating roller 13 is driven as the fixing film 7 is rotated to form a thin film of the separating agent on the surface of the fixing film. Then when un unfixed toner image on the surface of a recording material sheet P is fixed, part of toner is transferred to the surface of the fixing film 7, but moved to the oil coating roller 13 as the fixing film 7 and offset toner on the surface of the fixing film 7 is removed to clean the fixing film surface. Consequently, the surface of the fixing film 7 is held in a clean surface state for a long period to prevent image quality from deteriorating and the life of the film from becoming short.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention involves bringing a recording material carrying a visible image (hereinafter referred to as a toner image) to be heat-fixed into close contact with a heating body through a film. The present invention relates to a film heating type fixing device that heats and fixes a toner image by applying thermal energy from a heating body to a recording material via a film.

This equipment includes copying machines, laser beam printers, facsimile machines, microfilm reader printers, and image display (
In an image forming apparatus such as a display device or a recording machine, a recording material as an image carrier is produced using a toner made of heat-meltable resin or the like by an appropriate image forming process means such as electrophotography, electrostatic recording, or magnetic recording. An unfixed toner image corresponding to the desired image information formed directly or indirectly (transfer) on the surface of (electrofax sheet, electrostatic recording sheet, transfer material sheet, printing paper, etc.) and carrying the image. It can be used as an image fixing device that heats and fixes a permanently fixed image on the surface of a recording material.

(Prior Art) Conventionally, in a heating type fixing device, an unfixed toner image is formed by a heating roller maintained at a predetermined temperature and a pressure roller having an elastic layer and in pressure contact with the heating roller. A heat roller fixing type fixing device that heats the recorded recording material while nipping and conveying it is often used.

However, this heat roller fixing type fixing device has the following problems:
A so-called wait time is required to raise the temperature to a predetermined temperature (time during which image formation is prohibited).Secondly, heat capacity is required, which requires a relatively large amount of electric power.Thirdly, rotation Since the roller temperature is high, special heat-resistant bearings are required.Fourthly, the rollers are in direct contact with the hands, which may be dangerous and require protective members.Fifthly, the roller fusing temperature is high. Also, due to the curvature, the recording material may become wrapped around the recording material, causing a jam.

Therefore, as a heating type fixing device that does not have the above-mentioned drawbacks, a film heating type fixing device as described above has recently attracted attention, and research and development for its practical use is progressing.

For example, Japanese Patent Application Laid-Open No. 63-3131 related to the applicant's previous proposal
The method, device, etc. disclosed in Publication No. 82 belongs to this category, and includes a thin heat-resistant film (sheet), a means for moving the film, and a device fixedly supported on one side of the film with the film inside. a heating member, and a pressure member disposed on the other side facing the heating member to bring 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 film; At least when performing image fixing, the film is moved at the same speed in the same direction as the recording material on which the image is to be fixed, which is conveyed and introduced between the film and the pressure member, and is heated with the heating body with the moving film in between. By passing through a fixing nip formed by pressure contact with a pressure member, the image-bearing surface of the recording material is heated by the heating body through the film, and the image (
Applying thermal energy to the unfixed toner image (unfixed toner image) to soften and melt it, and then separating the film and recording material.
/J This is a heating means and device that basically separates the film and recording material after the toner has cooled and solidified.

As a heating element, a horizontally long heat-resistant/insulating/low-heat-capacity heater substrate with the longitudinal direction of the film as its longitudinal direction is provided with a low-heat-capacity heater board in the form of a line or strip along the length of the film on the film-contacting surface side. A type equipped with a current-carrying heating resistor (heating element) is used, and when power is supplied between both ends of the heating element, the heating element generates heat, and the heater board is also heated, causing the entire heating element to heat up. The temperature rises rapidly, and the heat from the heating body is applied to the recording material through the film.

The temperature of the heating element is controlled to a predetermined fixing temperature by a temperature sensor provided on the heating element, a microcomputer in the main body of the image forming apparatus, and a heating element driving (heating by energization) circuit. Furthermore, although the heating element is at a high temperature, at least when the heating element generates heat, the film is moved and driven over the heating element at a predetermined speed, so local thermal deformation of the film does not occur and stable image fixation is achieved. is executed.

Such a film heating type fixing device has features such as a short wait time, and is a fixing device that meets the needs of the times.

(Problems to be Solved by the Invention) However, one of the problems with this fixing device is that some of the toner in the unfixed image is lost when the device is used for a long time.
Due to the environment, the material of the recording paper, etc., there have been cases where a phenomenon of transfer to the fixing film, that is, an offset occurs. When offset occurs, the fixing film gradually becomes dirty, and eventually the toner is offset again onto the surface of the recording material, producing a defective image and shortening the life of the fixing film.

Therefore, in order to remove the offset toner on the fixing film, there is a method in which a plate-shaped rubber blade is used to remove the offset toner from the fixing film surface, or a web method in which a nonwoven fabric is impregnated with silicone oil and brought into pressure contact with the fixing film to clean the toner. In either case, the cleaning member presses against the thin fixing film, causing the fixing film to shift and wrinkle, causing some fixing failures, and eventually the wrinkles progress and the film eventually breaks. This may result in damage.

Alternatively, scratches on the release layer coated on the surface of the fixing film and partial peeling of the release layer may cause permanent offset on the fixing film and the image.

The present invention solves the above problems and improves the durability and reliability of this type of fixing device by preventing toner offset with respect to the fixing film surface over a long period of time with a simple and inexpensive means configuration. The purpose is to

(Means for Solving the Problems) The present invention includes a running film, a heating body and a pressure member that press the film in between, and pressurizes the heating body and the pressure member with the film sandwiched therebetween. A recording material carrying an unfixed visible image is introduced between the film and the pressure member in the fixing nip formed by the heating element, and is moved through the fixing nip together with the running film. A fixing device that heats and fixes a visible image by applying thermal energy to a recording material, and has a release agent supply means or a cleaning means for applying and supplying a release agent to the surface of the fixing film that contacts the recording material; is a fixing device characterized by being a rotating body.

Further, in the above fixing device, the present invention provides that the rotating body serving as the release agent supplying means or the cleaning means has at least a heat-resistant felt layer impregnated with a release agent in its outer layer, and is in contact with the fixing film and rotates drivenly. The release agent application roller is a release agent application roller that is a release agent application roller, and the release agent application area on the fixing film surface by the release agent supplying means or cleaning means is shorter than the width of the fixing film in a direction perpendicular to the conveying direction of the recording material. This fixing device is characterized by the following.

(Function) By applying a release agent to the fixing film, the offset of the developer (toner) to the fixing film is reduced, and even if offset occurs, the offset developer is removed by the movement of the fixing film. When the release agent reaches the position of the release agent supplying means or cleaning means, it is removed from the fixing film surface by the means, and a new release agent is applied and supplied to the fixing film surface, so that the fixing film surface remains clean for a long time. This condition is maintained, and the progress of staining due to the adhesion and accumulation of offset developer on the film surface, deterioration of image quality due to re-offset to the recording material surface, and shortening of the film's lifespan are prevented.

Since the release agent supplying means or cleaning means for applying and supplying the release agent to the fixing film surface is a rotating body, there is no excessive load on the fixing film, and there is no wrinkle in the film or peeling of the release layer on the film surface. It is possible to prevent offset by stable oil application and cleaning without any problems.

The release agent applied to the surface of the fixing film reduces the friction between the fixing film and the pressure member at the fixing nip, and has the effect of smoothing out wrinkles due to the sliding effect when wrinkles are likely to occur in the film.

Even if a jam of the recording material occurs in the fixing nip, cleaning can be performed without offset to the pressure member or the like.

While the recording material is passing through the fixing nip, the surface of the fixing film coated with a release agent comes into contact with the recording material surface. There is almost no adhesion of the release agent to the surface.

Even if there is adhesion, the amount is extremely small and does not cause any release agent smear on the surface of the recording material.

(Embodiment) (1) Example construction of a fixing device (Figs. 1 to 3) a) Device configuration Fig. 1 is a side view of an example of a fixing device 50 according to the present invention, Fig. 2 is a rear view, and Fig. 3 is a side view of an example of a fixing device 50 according to the present invention. The figure is a schematic diagram of the layer structure of the fixing film.

7 is an endless belt-shaped fixing film, which includes a driving roller 8 on the left side, a driven roller 9 on the right side, and both rollers 8.
- A low heat capacity linear heating element 1 as a heating element placed below between the three members 8, 9, and 1 is suspended and stretched between the three members 8, 9, and 1.

The driven roller 9 also serves as a tension roller for the endless belt-shaped fixing film 7.
is a predetermined circumferential speed in the clockwise direction as the driving roller 8 is rotated in the clockwise direction, that is, the same circumferential speed as the conveyance speed of the recording material P carrying the unfixed toner image Ta on the upper surface conveyed from the image forming section side. It is rotated without wrinkling, meandering, or speed lag.

Reference numeral 10 denotes a pressure roller having a rubber elastic layer 12 of silicone rubber or the like having good mold releasability as a pressure member. The lower surface of the recording material P is pressed against the lower surface thereof with a total contact pressure of, for example, 4 to 7 kg by a biasing means (not shown), and rotates about the shaft 11 in a forward counterclockwise direction in the conveying direction of the recording material P. .

The heating element 1 is a low heat capacity linear heating element whose length is in the direction (width direction of the film) that intersects the plane movement direction of the film 7, and includes a heater substrate 3, a current-carrying heating resistor (heating element) 4, and a temperature measuring element 5. etc., and is attached to the heater support 2 for fixed support.

The heater support 2 has heat insulation properties, high heat resistance, and rigidity to thermally support the heating body 1 with respect to the fixing device 50 and the image forming device, and is made of, for example, PP5 (polyphenylene sulfide), FAI (polyamideimide), PI (polyimide). )
- It can be composed of highly heat-resistant resins such as PEEK (polyetheretherketone) and liquid crystal polymers, and composite materials of these resins and ceramics, metals, glass, etc.

The heater board 3 is made of a heat-resistant, insulating, and low heat capacity material, and has, for example, a thickness of 1.0 mm, a width of 16 mm, and a length of 340 mm.
mm alumina substrate.

The heating element 4 is made of an electrically resistive material such as Ag/Pd (silver palladium) or Ta2N with a thickness of about 10 μm along a long plane approximately at the center of the lower surface of the substrate 3 (the side facing the film 7).
It is coated to a width of 1 to 3 mm by screen printing or the like, and then a heat-resistant glass 6 of about 10 μm is coated thereon as a surface protective layer.

The temperature measuring element 5 is, for example, a temperature measuring element with a low heat capacity such as a PT film coated on the upper surface of the substrate 3 (the surface opposite to the surface on which the heating element 4 is provided) approximately at the center by screen printing or the like. It is a resistor. As the temperature measuring element, a thermistor having a low heat capacity or the like may be arranged in contact with the substrate 3.

In the case of the heating element 1 of this example, the heating element 4 is linear or strip-shaped.
The heating element 4 is energized from both ends in the longitudinal direction to generate heat over substantially the entire length of the heating element 4.

The power is supplied by AClooV, and the power to be supplied is controlled by controlling the phase angle of the current by a power supply control circuit (not shown) including a triac in accordance with the temperature detected by the temperature measuring element 5.

The fixing film 7 can be a single layer or composite layer film that has heat resistance, mold releasability, durability, etc. and generally has a total thickness of 100 μm or less, preferably 40 μm or less.

FIG. 3 is a schematic diagram of the layer structure of an example of a composite layer film,
This example is a two-layer film. 7b is a heat-resistant layer as a base layer (base film) of the fixing film, and 7a is a release layer laminated on the outer surface (the surface facing the toner image) of the heat-resistant layer 7b.

The heat-resistant layer 7b is made of polyimide, polyether ether ketone (PEEK), polyether sulfone (PE), for example.
S), polyetherimide (PEI) polyparabanic acid (
Highly heat-resistant resin films such as PPA), Ni-5U
Materials with excellent strength and heat resistance, such as metals such as S-A1, can be used.

The release layer 7a is preferably made of, for example, fluororesin such as PTFE (polytetrafluoroethylene)/PFA-FEP, silicone resin, etc. (PTFE is used in this example). The surface resistance value of the fixing film 7 can also be lowered by mixing a conductive agent such as carbon black, graphite, or conductive whiskers into the release layer 7a. Thereby, charging of the toner contacting surface of the fixing film 7 can be prevented.

The release layer 7a is laminated on the heat-resistant layer 7b by adhesive lamination of the release layer film, by lamination of the release layer material by electrostatic coating, vapor deposition, CVD, or other film-forming techniques, or by the heat-resistant layer material and the release layer. This can be done by forming a two-layer film by coextruding materials.

Reference numeral 13 denotes an oil application roller serving as a release agent supply means for applying and supplying a release agent to the fixing film 7. This roller will be described in detail in section C) below.

b) Fixing Execution Operation An image forming device (not shown) performs an image forming operation in response to an image forming start signal, and the recording material sheet P carrying an unfixed toner image Ta on its upper surface, which is conveyed to the fixing device 50, is moved to the guide 18. The fixing film 7 and the pressure roller 1 are guided to a pressure contact portion (fixing nip portion) between the heating body 1 and the pressure roller 10.
0, and the unfixed toner image surface comes into close contact with the lower surface of the fixing film 7, which is rotating in the same direction at the same speed as the conveyance speed of the sheet P, causing surface misalignment, wrinkles, and deviation. The fixing film 7 passes through the mutual pressure contact portion of the heating body 1 and the pressure roller 10 while being subjected to a squeezing force while being overlapped with the fixing film 7.

The heating body 1 is energized and heated at a predetermined timing in response to an image formation start signal, so that the toner image Ta is heated at the pressure contact portion and becomes a softened and melted image Tb.

The running direction of the fixing film 7 is turned at an acute angle (bending angle θ of approximately 45°) at an edge portion S of the heater support 2 having a large curvature (the radius of curvature is approximately 2 mm). Therefore,
The sheet P, which is conveyed through the pressure contact portion while overlapping the fixing film 7, is transferred to the fixing film 7 at the edge portion S.
The paper is separated by the curvature from the paper and is ejected to the paper ejection tray. By the time the sheet is ejected, the toner has been sufficiently cooled and solidified and is completely fixed on the sheet P (toner image Tc).

Furthermore, in this example, among the heating elements 1, the heating element 4 and the substrate 3
Since the heat capacity of the toner is small and these are supported by the support member 2 insulatingly, the surface temperature of the heating member 1 at the pressure contact portion becomes sufficient for the melting point of the toner (or the temperature at which it can be fixed on the sheet P) in a short period of time. There is no need to raise the temperature of the heating element 1 in advance (so-called standby temperature control) before raising the temperature to a high temperature, and energy saving can be realized, and temperature rise inside the machine can also be prevented.

Station c) Ill type and supply means As mentioned above, the unfixed toner image on the surface of the recording material sheet 11 introduced into the fixing device 50 is transferred to the fixing film and the pressure roller 1.
By passing through the fixing nip, which is a pressure contact area with the fixing film 7, the fixing film 7 is heated by the heating element 4 of the heating element 1, and is melted and fixed onto the sheet P. At this time, a small portion of the toner is transferred to the surface of the fixing film 7 (toner offset). If no treatment is performed, this transferred toner remains attached to the fixing film 7 and comes into contact with the sheet P again as the film rotates. Since the amount of toner is small and its adhesion to the film is relatively strong, some of the toner is transferred again to the surface of the sheet 11 (toner re-offset), while other toner remains on the surface of the fixing film 7. Due to this toner offset/re-offset, the surface of the fixing film 7 gradually becomes dirty, causing problems such as shortened service life and lowered image quality as described above.

Therefore, in this embodiment, the fixing film 7 is sandwiched between the fixing film drive roller 8 and the fixing film drive roller 8, and an oil application roller 13 as a releasing agent supply means is provided in pressure contact with the fixing film surface.

The oil application roller 13 has a rotating shaft 16 as a core metal, a silicone sponge layer 15 with a thickness t=4 mm as an intermediate layer, that is, an elastic layer, and a heat-resistant felt force as a surface layer with a thickness of 1.5 mm and a density of 0. , 3 g/cm3, and the felt layer 14 is almost uniformly impregnated with about 7 to 15 g of silicone oil having a viscosity of 10,000 cs as a mold release agent.

The oil application roller 13 is parallel to the fixing film drive roller 8, and is pressed against the surface of the fixing film with a pressure of 100 to 500 g, with the fixing film 7 sandwiched between the drive roller 8 and the drive roller 8 by its own weight or by the pressing force of the pressing spring 17. kept in condition. The silicone sponge layer 15 as an intermediate elastic layer of the roller 13 has elasticity that allows the roller 13 to come into pressure contact with the driving roller 8 with the fixing film 7 interposed therebetween to create a sufficient nip.

As the oil application roller 13 rotates as the fixing film 7 rotates, silicone oil as a release agent is applied and supplied to the surface of the fixing film, forming a thin layer of oil. . The felt layer 14 for supplying oil also has an oil-absorbing effect, so that no excess oil is supplied to the surface of the fixing film 7, and a thin layer coated with oil is always formed with a substantially constant amount of oil.

The unfixed toner image on the surface of the recording material sheet 11 introduced into the fixing device 50 is heated by the heating element 4 of the heating element 1 at the fixing nip portion via the fixing film 7 on which a thin layer of silicone oil is formed. It is melted and fixed on the surface of the sheet 11. At that time, a small portion of the toner is transferred to the surface of the fixing film 7 on which a thin layer of oil is formed (offset). This transferred toner will be fixed by 2g/7.
With the rotation of the fixing film 7, the oil application roller 13 is moved again via the fixing film 7 to the position of the oil application roller 13, which is in pressure contact with the drive roller 8 while remaining attached to the surface, and the oil application roller 13 and the drive roller 8 are brought into pressure contact. The offset toner on the surface of the fixing film 7 is removed and the surface of the fixing film is cleaned, and a new thin oil layer is formed on the surface of the fixing film 7. The operation cycle of rotating and moving is repeated.

By repeating the above operations, the surface of the fixing film 7 is maintained in a clean state for a long period of time, leading to progress of staining due to the accumulation of offset toner on the surface of the film, deterioration of image quality due to re-offset to the surface of the recording material, and shortening of the film's lifespan. This prevents damage, etc.

While the sheet P is passing through the fixing nip, a thin layer of oil on the surface of the fixing film 7 comes into contact with the surface of the sheet P, but since the amount of oil is extremely small, it is almost never attached to the sheet P, and even if it is, it is extremely rare. Since it is a small amount, it will not cause oil stains.

As shown in FIG. 2, the neutral 2 in the longitudinal direction of the oil supply of the oil application roller 13 is smaller than the width of the fixing film 7 in the longitudinal direction.

That is, it is set so that 2□<dan.

This means that if the width C2 in the longitudinal direction of the oil supply of the oil application roller 13 is longer than the width Il of the fixing film 7, the oil application roller 13
Because it comes into direct contact with the drive roller 8 without going through the fixing film 7, oil adheres to the drive roller 8, and the oil gets around between the drive roller 8 and the fixing film 7, reducing the driving force of the fixing film 7. This is to prevent slippage from occurring.

On the other hand, the middle angle of the fixing film 7 in the longitudinal direction is made wider than the peak angle 3 of the heating element 4 in the longitudinal direction.

That is, the fixing film 7 is also a heat absorbing means, and if the film 7 is not in the area of the heating element 4, the heating element in that area will locally cause an abnormal temperature rise, leading to destruction of the heating element 1. It is.

Further, the middle angle in the longitudinal direction of the pressure roller 10 is made shorter than the middle angle in the longitudinal direction of the fixing film 7.

This is because if the pressure roller 10 comes into contact with the heating element 1 without intervening the film 7, the rotational force of the pressure roller 10 will gradually wear out the contact area of the heating element 1, eventually causing the heating element 1 to break. This is because it leads to

In this embodiment, (1) the oil application roller 13, which is a rotating body serving as an S-shape supplying means, is driven to rotate as the fixing film 7 is moved, so that no undue load is applied to the fixing film 7; Toner offset can be prevented by stable oil application and cleaning without wrinkles or peeling of the release layer 7a.

(2) Even if a jam such as a paper jam occurs at the fixing nip, cleaning can be performed without offset to the pressure roller 1o or the like.

(2) Since the oil application roller 13 is not in contact with the heating element 1, it receives heat only during the image forming operation from the fixing film 7 heated by the heating element 1 and the drive roller 8 accumulated via the fixing film. Since the impregnated oil as a mold release agent swells, the life of the oil application roller 13, which releases excess oil, can be extended.

(2) It is possible to prevent the film from shifting or wrinkling, which is a problem when the film surface is cleaned by pressing a cleaning plate or a web member against the film surface.

(2) The oil applied to the surface of the fixing film reduces the friction between the fixing film 7 and the pressure roller 1o at the fixing nip, and when wrinkles are about to appear on the film, the wrinkles are smoothed out due to the sliding effect.

(2) Fixing device example II (Fig. 4) In this example, the oil application roller 13 is placed at the position of the fixing film driven roller 9, and the fixing film 7 is sandwiched between the driven roller 9 and the fixing film surface by its own weight. Alternatively, it is arranged such that it is maintained in a pressed state with a pressing force of 100 to 500 g by the pressing spring 17. The other configurations are the same as those of the above-described fixing device example I, and have the same functions and effects.

(3) Fixing device example m (FIG. 5) In this example, the oil application roller 13 is applied to the surface of the fixing film at approximately the midpoint of the fixing film portion between the fixing film drive roller 8 and the driven roller 9. The pressure contact is maintained by light pressure by the force of the pressure spring 17 or by the pressure force of the pressure spring 17. The other configurations are the same as those of the fixing device example described above, and have the same functions and effects.

In addition, this embodiment also has the following unique effects.

(2) By increasing the contact area between the fixing film 7 and the oil application roller 13, the oil application effect and cleaning effect are improved.

(2) Even if the fixing film 7 elongates due to long-term use, the oil application roller 13 functions as a tension roller and the elongation is absorbed by its tension effect.

The effects shown in (1) and (2) make it possible to further extend the life of the fixing film.

(4) Image device example (Figure 6) Figure 6 shows the fixing device 50 of the example in Figure 1 (fixing device example ■) described above.
1 shows a schematic configuration of an example of an image forming apparatus using the image forming apparatus.

The image forming apparatus of this example is an electrophotographic copying apparatus of a fixed document table/moving optical system type, a rotating drum type, and a transfer type.

Place the original 19 as required on the fixed original table glass 20,
After setting the required copying conditions, when the copy start key is pressed, the photosensitive tram 39 is rotated clockwise as indicated by the arrow at a predetermined circumferential speed.

In addition, the light source 21 (22 is a reflective shade) and the first mirror 23 move along the lower surface of the document table glass 20 from the home position on the left side of the glass to the right side of the glass at a predetermined speed V, and the second and third mirrors move forward at a predetermined speed V. By moving the mirrors 24 and 25 in the same direction at a speed of V/2, the original 1 placed on the R platen glass 20-E is
The downward image plane of 9 is illuminated and scanned from the left side to the right side,
The reflected light from the document surface of the illumination scanning light is image-formed and exposed (slit exposure) onto the surface of the rotary photoreceptor tram 39 via the imaging lens 29 and the fixed fourth to sixth mirrors 26, 27, and 28.

The surface of the rotary photoreceptor tram 39 is uniformly charged to a predetermined positive or negative potential by the primary charger 30 before this exposure, and by exposing this charged surface to the above-mentioned light, the drum Electrostatic latent images in a pattern corresponding to the original image are sequentially formed on the 39th surface. The electrostatic latent image formed on the surface of the photosensitive drum 39 is developed as a toner image by a developing roller 32 of a developing device 31.

On the other hand, a transfer material sheet P as a recording material is fed by a paper feeding means (not shown), passes through a guide 33, is introduced into a transfer section between a drum 39 and a transfer charger 34 at a predetermined timing, and is transferred into a transfer corona. The toner image on the surface of the drum 39 which is in contact with the drum 39 is sequentially transferred onto the surface of the sheet 11.

The sheet P that has passed through the image transfer section is transferred to the drum 3 by an unillustrated separating means (for example, a separating belt disposed at the end of the tram).
It is sequentially separated from the nine sides, undergoes charge removal from the back side by the charge removal needle 35, and is transferred to the fixing device 50 by the conveyance section 38 and guide 18.
As described above, the toner is introduced into the machine, where the toner is fixed, and is discharged outside the machine as an image-formed product.

After the transfer, the surface of the drum 39 is cleaned by removing dirt such as residual toner with a cleaning blade 37 of a cleaning device 36, and is repeatedly used for image formation.

[Brief explanation of drawings]

FIG. 1 is a side view of the fixing device of the first embodiment. Figure 2 is a rear view. FIG. 3 is a schematic diagram of an example of the layer structure (two layers) of the fixing film. FIG. 4 is a side view of the fixing device of the second embodiment. FIG. 5 is a side view of the fixing device of the third embodiment. FIG. 6 is a schematic configuration diagram of an example of an image forming apparatus. (Effects of the Invention) As described above, the present invention can remove offset toner transferred to the fixing film surface of a film heating type fixing device without the above-mentioned problems. It is possible to improve durability and reliability, and the intended purpose is well achieved. / 1 is a heating element, 3 is a heater board, 4 is a heating element (current-carrying heating resistor), 5 is a temperature measuring element, 7 is a fixing film, 10 is a pressure roller, and 13 is an oil (AM-shaped coating roller).

Claims (3)

[Claims] (1) It has a running film, a heating body and a pressure member that sandwich and press it, and the film and the fixing nip formed by the pressure between the heating body and the pressure member sandwich the film. A recording material carrying an unfixed visible image is introduced between the pressure member and the running film moves through the fixing nip section, and thermal energy is applied to the recording material from the heating element through the film to heat the visible image. A fixing device that performs fixing, the fixing device having a release agent supply means or a cleaning means for applying and supplying a release agent to the recording material contacting side of the fixing film, and the means being a rotating body. . (2) The rotating body serving as the release agent supply means or the cleaning means is a release agent application roller that has at least a heat-resistant felt layer impregnated with a release agent in its outer layer and rotates in contact with the fixing film. The fixing device according to claim 1, characterized in that: (3) The area to which the release agent is applied on the surface of the fixing film by the release agent supplying means or the cleaning means is shorter than the width of the fixing film in a direction perpendicular to the conveyance direction of the recording material. The fixing device described in 2.