JPH03210587A - Fixing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a film heating method in which a recording material is brought into close contact with a heating body through a film, and thermal energy is applied from the heating body to the recording material through the film. The present invention relates to a fixing device.

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 recorder, a toner made of heat-meltable resin or the like is used as an image carrier 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 a recording material (electrofax sheet, electrostatic recording sheet, transfer material sheet, printing paper, etc.) is transferred to the surface of the recording material (electrofax sheet, electrostatic recording sheet, transfer material sheet, printing paper, etc.). It can be used as an image fixing device that heats and fixes an image as a permanently fixed image on the surface of the recording material.

Further, the present invention is not limited to an image fixing device, and can be widely used as a means/device for heat-treating an image carrier, such as a device that heats a recording material carrying an image to modify its surface properties.

(Prior Art) Film heating type fixing devices include other known heat roller type, hot plate type, and belt fixing type (U.S. Patent No. 3.
578.797 Specification) In comparison with thermal fixing devices such as flash fixing method and open fixing method, (1) A linear heating element with a low heat capacity can be used as a heating element (thermal heater), resulting in power saving and Wait time is shortened (quick start performance); ■Fixing point and separation point can be set separately, so offset is prevented;
It is effective and has the advantage of being able to overcome various drawbacks of other systems.

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 (
Heating means that basically applies heat energy to soften and melt the unfixed toner image (unfixed toner image) and then separates the film and recording material, or separates the film and recording material after the toner has cooled and solidified. It is a device.

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 and a heating element driving (current generation) circuit of the main body of the image forming apparatus. Furthermore, although the heating element is at a high temperature, at least when the heating element is generating heat, the film is moved and driven over the heating element at a predetermined speed, so that local thermal deformation of the film does not occur and stable images can be obtained. Fixation is performed.

(Problems to be Solved by the Invention) In this fixing device, when a phenomenon in which a part of the toner from an unfixed image is transferred to the fixing film during fixing, that is, offset occurs, the fixing film gradually gets dirty and eventually reaches the surface of the recording material. The toner will re-offset, resulting in a defective image and the fuser film will have a short lifespan.

Therefore, in order to remove the offset toner on the fixing film, there is a method of cleaning the offset toner from the fixing film surface with a plate-shaped rubber blade, or a web method of cleaning the toner by impregnating a non-woven fabric with silicone oil and pressing it against the fixing film. However, in both cases, the cleaning member presses against the thin fixing film, causing the fixing film to shift and wrinkle, causing some fixing failures. The result is as follows.

The occurrence of the above-mentioned shifting and wrinkles of the fixing film becomes more noticeable when there is an imbalance in the lengthwise direction of the cleaning member in the pressing state of the cleaning member against the fixing film.

An object of the present invention is to improve the durability and reliability of this type of fixing device by making it possible to remove offset toner transferred to the fixing film surface without the above-mentioned problems.

(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 fixing method in which a recording material is introduced between the film and the pressure member in the fixing nip formed by the film, and the recording material is moved through the fixing nip along with the running film, thereby applying thermal energy to the recording material from a heating element through the film. The fixing device is characterized in that it is provided with a release agent application member that applies a release agent to a pressure member.

Further, the present invention provides that the release agent application member of the fixing device has a heat-resistant felt layer as an outer layer, and the release agent application roller that rotates in contact with the pressure member contacts the pressure member. The fixing device is characterized in that it includes a pressure contact area that is formed.

(Function) ① A layer of release agent is formed on the surface of the pressure member by the release agent coating member, so that the recording material passes through the fixing nip and the film (fixing film) and the pressure member are separated. When a state of direct contact occurs, the offset toner on the fixing film surface side adheres and transfers to the release agent coated layer surface of the pressure member at the direct contact portion. That is, the pressure member coated with the release agent functions as a cleaning member to effectively remove the offset toner from the fixing film surface (cleaning the film surface).

■The toner that adheres and transfers from the fixing film side to the pressure member side reaches the pressure contact area between the pressure member and the release agent coating member as the pressure member moves, and is taken into the release agent coating member. and removed from the pressure member surface. That is, the release agent application member functions as a cleaning member to clean the surface of the pressure member, and the release agent application member also applies a new release agent to the surface of the pressure member. As the surface moves, the coated surface comes into pressure contact with the fixing film.

The pressure member surface may be cleaned by bringing a dedicated cleaning member into contact with the pressure member surface.

By repeating the operations described in ■ and ■ above, offset toner is removed from the fixing film surface and a clean surface is maintained for a long period of time, and dirt progresses due to offset toner adhesion and accumulation on the film surface and re-offset to the recording material surface. This prevents deterioration of image quality and shortening of film life.

(2) By using a mold release agent that has good affinity with the surface material of the pressure member, transfer to the fixing film surface can be prevented.

■While the recording material is passing through the constant S nip, the pressure member coated with a release agent comes into contact with the back surface of the recording material, but the release agent only needs to be applied in a very small amount and in a thin layer to the pressure member. Adhesion of the release agent to the back surface of the recording material is hardly caused. Even if there is adhesion, the amount is extremely small and does not cause mold release agent ooze.

(2) Cleaning the film surface by causing a release agent coating member to act on the pressure member that is in pressure contact with the heating body with the fixing film sandwiched therebetween so that the pressure member functions as a cleaning member for the film surface. Therefore, 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 blade or a web member directly against the film surface.

■The release agent applied to the surface of the pressure member is applied to the fixing nip to reduce the friction between the fixing film and the pressure member, and if wrinkles are about to form on the film, the slipping effect will cause the wrinkles to extend. be.

(Example) (1) Example construction of the fixing device (Figs. 1 to 3) a) Device configuration Fig. 1 is a side view of an example of the fixing device M50 according to the present invention, and Fig. 2 shows the construction of the heating body, pressure roller, FIG. 3 is a front view of the oil application roller portion, and a schematic diagram of the layer structure of the soil-wearing film shown in Figure 3.

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 body 1 as a heating body placed below 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 transfer material sheet P, which is a recording material, carrying on its upper surface an unfixed toner image Ta conveyed from the image forming section (34) side at a predetermined circumferential speed in the clockwise direction as the driving roller 8 is rotated in the clockwise direction. It is rotated at the same circumferential speed as the conveyance speed without wrinkling, meandering, or speed lag.

Reference numeral 10 denotes a pressure roller having a rubber elastic layer 12 having good releasability, such as silicone rubber, as a pressure member. are brought into opposing pressure contact with the lower surface of the transfer material sheet P with a total pressure of, for example, 4 to 7 kg by a biasing means (not shown), and rotated about the shaft 11 in a forward and counterclockwise direction in the conveyance direction of the transfer material sheet P. .

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

The heater support 2 has heat insulation properties, high heat resistance, and rigidity to thermally support the heating body 1 to the fixing device M50 and the entire image forming apparatus, and is made of, for example, pps (polyphenylene sulfide), PAI (polyamideimide), PI ( It can be composed of highly heat-resistant resins such as polyimide (polyimide), PEE (polyetheretherketone), and liquid crystal polymer, as well as composite materials of these resins and ceramics, metals, glass, etc.

The heater board 3 is a heat-resistant, insulating, and low heat capacity member, and has a thickness of 1.0 mm, a width of 10 mm, and a length of 240 mm, for example.
■■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 approximately 10 μm along the length 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 is coated with heat-resistant glass 6 to a thickness of about 10 .mu.m 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 current 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 according to the temperature detected by the temperature measuring element 5.

As the fixing film 7, a single layer or composite layer film having heat resistance, releasability, durability, etc. and generally having a total thickness of 100 μm or less, preferably 40 μm or less can be used.

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 serving as a 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, for example, polyimide, polyetheretherketone (PEEK), polyethersulfone (PES).
), polyetherimide (PEI) polyparabanic acid (P
PA), etc., and Ni-5US.
- Metals with excellent strength and heat resistance, such as metals such as A11, can be used.

The release layer 7b is preferably made of, for example, a 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 7b. 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, and 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 for applying silicone oil as a mold release agent, for example, to the outer surface of the pressure roller 10, and is composed of a rotating shaft 16 and a silicone sponge layer 15 and a felt layer 14 sequentially formed on the outer periphery of the rotating shaft 16. Reference numeral 17 denotes a coil spring that always presses the oil application roller 13 against the pressure roller with an appropriate pressure. The silicone sponge layer 15 of the roller 13 has elasticity to create a sufficient pressure nip between the pressure roller 10 and the oil application roller 13. The felt layer 14 is pre-impregnated with silicone oil as a mold release agent.

The oil application roller 13 rotates in accordance with the rotation of the pressure roller 10 to coat and supply silicone oil as a mold release agent to the outer peripheral surface of the pressure roller 10.

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 unfixed toner image surface enters between the fixing film 7 and the pressure roller 10 at the pressure contact portion N (fixing nip portion) between the heating body 1 and the pressure roller 10, and the unfixed toner image surface is transferred to the sheet P.
The heating body 1 and the pressure roller 10 are in close contact with the lower surface of the fixing film 7 which is rotating in the same direction at the same speed as the conveying speed of It passes through the mutual pressure contact part N with the other while being subjected to a clamping force.

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 N and becomes a softened and melted image Tb.

The fixing film 7 is formed at a steep angle (bending angle θ
The direction of travel is changed at approximately 45 degrees). Therefore, the sheet P, which is conveyed through the pressure contact part N while overlapping with the fixing film 7, reaches the edge part S and is separated from the fixing film 7 by the white ratio, and is discharged to the paper discharge tray.

By the time the sheet is ejected, the toner has sufficiently cooled and solidified, and the sheet P
The toner image is completely fixed (toner image Tc).

Further, in this example, among the heating elements 1, the heating element 4 and the substrate 3
have a small heat capacity and are adiabatically supported by the support 2, so that the surface temperature of the heating element 1 at the pressure contact part N becomes lower than the melting point of the toner (or the temperature at which it can be fixed to the sheet P) in a short period of time. Since the temperature will be raised to a sufficiently high temperature, the temperature of the heating element 1 must be raised in advance (so-called standby temperature control).
There is no need for this, energy savings can be achieved, and temperature rise inside the machine can also be prevented.

C) Operation and Effect of Oil Application Roller 13 As described above, the unfixed toner image at the pressure contact portion N is heated and melted by the heating element 4 of the heating element 1 via the fixing film 7, and is 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). This transferred toner remains attached to the fixing film 7 and comes into contact with the sheet P again as the film rotates.

Since there is only a small amount of toner and its adhesion to the film is relatively strong, some of the toner is re-transferred to the second surface of the sheet (re-offset of the toner) and other toner remains on the 7th surface of the fixing film. 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.

This problem can be solved by applying and supplying a release agent to the pressure roller 10.

The oil application roller 13 has an outer diameter of φ18 (mm) and a length of 3.
It is 30mm. And the rotating shaft 16 which is the core metal
The intermediate layer, that is, the elastic layer, is composed of a silicone sponge layer 15 with a thickness of 4 mm, and the surface layer is a heat-resistant felt layer 14 made of heat-resistant felt with a thickness of 1.5 mm and a density of 0.3 g7cal. 14 is almost uniformly impregnated with about 7 to 15 g of silicone oil having a viscosity of 10,000 cs.

This oil application roller 13 is applied to the surface of the pressure roller 10.
are in pressure contact with each other with a pressure of 100 to 500 g and are driven to rotate, whereby silicone oil as a mold release agent is applied and supplied to form a thin layer of oil. The felt layer 14 for oil supply also has an oil absorption effect, and since it is in contact with the pressure roller 10, excess oil is not supplied to the surface of the pressure roller 10, and a substantially constant amount of oil is always maintained. A thin coating layer is formed.

When the sheet P passes through the pressure contact portion N, the pressure roller 10 directly contacts the outer surface of the fixing film 7 at the pressure contact portion N, and pressurizes the transferred toner present on the outer surface of the film 7 so that a thin layer of oil is formed. It adheres to the surface of the roller 10 and the film surface is cleaned. That is, the pressure roller 10
functions as a cleaning member for the cleaning surface 7.

The silicone oil serving as the release agent layer on the surface of the pressure roller has extremely good affinity with the silicone rubber layer 12 of the pressure roller 10 and is unlikely to transfer to the surface of the fixing film 7.

The toner transferred from the side of the fixing film 7 to the silicone oil layer on the surface of the pressure roller 10 reaches the pressure contact area between the pressure roller 10 and the oil application roller 13 as the pressure roller 10 rotates, and is transferred to the pressure contact area. Due to the elastic force of the silicone sponge layer 15 of the right roller 13 and the oil absorption effect of the felt layer 14, the oil is transferred to the oil application roller 13 side. That is, the oil application roller 13 functions as a cleaning member for the pressure roller 10.

New oil is applied and supplied as a thin layer to the surface of the pressure roller 10 by the oil application roller 13, and reaches the pressure contact portion N as the pressure roller 10 rotates.

By repeating the above operations, the offset toner is removed from the surface of the fixing film 7, and the surface remains clean for a long period of time. As a result, stains progress due to the accumulation of offset toner on the surface of the film 7, and the image is re-offset to the surface of the recording material. Degradation of quality, shortening of film life, etc. are prevented.

While the sheet P passes through the pressure contact part N, a thin layer of oil on the outer surface of the pressure roller 10 comes into contact with the back surface of the sheet P, but since the amount of oil is extremely small, it hardly ever adheres to the sheet P. Since the amount is extremely small, it will not cause oil stains.

As shown in FIG. 2, the width 12 in the longitudinal direction of the oil supply roller 13 is equal to the width 12 in the longitudinal direction of the pressure contact portion N formed by the fixing film 7 and the pressure roller 10. bigger. That is, 1゜>j2. It is set so that it is. This is because if some parts of the pressure contact area N formed by the fixing film 7 and the pressure roller 10 have oil and some parts do not, the fixing film may wrinkle due to frictional force occurring at each pressure contact part N. This is because misalignment may occur, leading to damage to the fixing film 7.

On the other hand, the width of the fixing film 7 in the longitudinal direction is 1. is made wider than the longitudinal width It4 of the heating element 4.

That is, the fixing film 7 is also a heat absorbing means, and if the film 7 is not present 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.

Further, the width f in the longitudinal direction of the pressure roller 10 is made shorter than the width It3 in the longitudinal direction of the fixing film 7.

This is because if there is a part of the pressure roller 10 that 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 part of the heating element 1 that it contacts, eventually causing the heating element 1 to break. This is because it connects with

As described above, the oil application roller 13 as a release agent application member is applied to the pressure roller 10 as a pressure member that is in pressure contact with the heating body 1 with the fixing film sandwiched therebetween. By cleaning the 7th side of the film by using it as a cleaning member for the 7th film side, it is possible to eliminate the deviation and wrinkles of the film, which are problems when the cleaning blade or web member is pressed against the 7th side of the film to clean the film side. Occurrence can be prevented.

Also, the oil on the pressure roller 10 surface is in the fixing nip NeJ3.
This also has the effect of reducing the friction between the fixing film and the pressure roller 10, so that if wrinkles or the like are likely to occur on the film, the wrinkles will be extended due to the sliding effect.

(2) Example of a fixing device ■ (FIG. 4) The means for applying and supplying oil as a release agent to the pressure roller 1o as a pressure member is not limited to the roller body.

In this embodiment, a pad body 40 is used as in the example shown in FIG.

41 is a heat-resistant felt layer with a thickness of 10 mm and a density of 0.
4g7cm” with a viscosity of 6000cs as a mold release agent.
The entire surface is uniformly impregnated with 10 to 30 g of silicone oil.

42 is a holder that supports the felt 41, and is made of heat-resistant plastic, such as PBT (polybutylene terephthalate).
It is made of.

This oil application pad 40 is pressed once with a pressing member such as a spring 17.
It is pressed against the pressure roller 1o with a pressing force of 00 to 400 g.

This oil application pad 40 also has the same effect as the case where the oil application roller 13 of the above-mentioned example is used. The unique advantages of this oil application pad 40 are that it has a simple structure, is inexpensive, and has excellent replaceability.

(3) Fixing device example m (FIG. 5) The device of this example includes a driving roller 8, a driven roller 9, a heating element 1, and a separation stay 43 disposed downstream of the heating element 1 in the film running direction. The four members 8 and 9 parallel to each other
・An endless belt-like fixing film was hung and stretched between 1 and 43.

Reference numeral 44 denotes a lower separation roller disposed facing the separation stay 43 with the fixing film 7 placed therein below the separation stay 43, and 46 a lower separation roller suspended between the pressure roller 10 for the heating element 1 and the lower separation roller 44. This is a tensioned endless belt-like recording material conveying belt, which rotates as the fixing film 7 rotates.

At the belt hanging portion of the pressure roller 10, the oil application roller 13 is brought into pressure contact with the outer surface of the belt 46 in the same way as the pressure roller 10 of the device example described above, and as the belt 46 rotates, the oil application roller 13 is pressed against the outer surface of the belt 46. As the belt 46 rotates, a thin layer of silicone oil as a mold release agent is applied and supplied to the outer surface of the belt 46 .

After the recording sheet P is introduced into the fixing nip N and is heated, it is conveyed as it is to the separation stay 43 and the lower separation roller 44 by the conveyor belt 46 while maintaining close contact with the surface of the fixing film 7. The fixing film is cooled and solidified, and the fixing film is successively separated by curvature from the 7th surface at the position of the separation stay 43.

In this way, the unfixed toner on the sheet P is heated and melted at the fixing nip N to be fixed, and then the fixing film 7
The toner is kept in close contact with the surface, sufficiently cooled and solidified, and separated from the fixing film surface at the separation stay 43, making it difficult for the toner to transfer (offset) to the fixing film 7 surface.
Toner offset can be reduced.

Even if offset occurs, the conveyor belt 46 coated with oil functions as a cleaning member to remove the offset toner from the surface of the fixing film 7, as in the case of the pressure roller 10 of the above-mentioned device example and the same (2). The film surface is cleaned.

Since the conveyor belt 46 in this embodiment is simply a means for conveying the recording material P, it has sufficient thickness and sufficient strength, and even if the oil application roller 13 is unevenly applied, it will not wrinkle if it leans against the conveyor belt 46. will never occur.

(4) Example of an image forming apparatus (FIG. 6) FIG. 6 shows a schematic configuration of an example of an image forming apparatus using the fixing device 5o of the example shown in FIG. 1 described above.

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 2o,
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.

Further, the light source 21 (22 is a reflective shade) and the first mirror 23 move forward at a predetermined speed V along the lower surface of the document table glass 2o from the name position on the left side of the glass to the right side of the glass. By moving the mirrors 24 and 25 in the same direction at a speed of V/2, the original 19 placed on the original platen glass 20 is
The downward image surface of the image plane is illuminated and scanned from the left side to the right side, and the light reflected from the illumination scanning light on the document surface passes through the imaging lens 29 and fixed fourth to sixth mirrors 26, 27, and 28 to the surface of the rotating photoreceptor drum 39. image formation exposure (slit exposure).

Before this exposure, the surface of the rotating photosensitive drum 39 is uniformly charged to a predetermined positive or negative potential by the primary charger 30, 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 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 tram 39 and a transfer charger 34 at a predetermined timing, and is transferred into a transfer corona. As a result, the toner image on the side of the drum 39 in contact with the drum 39 is sequentially transferred to the second side of the sheet.

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 drum).
It is sequentially separated from the nine sides, subjected to charge removal from the back side by the charge removal needle 35, and transferred to the fixing device 50 by the conveying section 38/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 by a cleaning blade 37 of a cleaning device 36, and is used repeatedly for image formation.

(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.

[Brief explanation of drawings]

Fig. 1 is a side view of the fixing device of the first embodiment, Fig. 2 is a front view of the heating element, pressure roller, and oil application roller, and Fig. 3 is an example of the layer structure (two layers) of the fixing film. Model diagram, 4th
5 is a side view of the fixing device of the third embodiment, and FIG. 6 is a schematic configuration diagram of an example of an image forming apparatus. 1 is a heating element, 3 is a heater board, 4 is a heating element (current-carrying heat generating resistor), 5 is a temperature measuring element, 7 is a fixing film, 10 is a pressure roller, 13 and 40 are oil (release agent) coating parts. Laura or Bud.

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. This is a fixing device that applies thermal energy to the recording material from a heating element through the film by introducing the recording material between the pressure member and the traveling film through the fixing nip, and applying a release agent to the pressure member. 1. A fixing device comprising a release agent application member for applying a mold release agent. (2) The fixing device according to claim 1, wherein the release agent application member is a release agent application roller that has a heat-resistant felt layer as an outer layer and rotates in contact with the pressure member. (3) The application area in the axial direction applied to the pressure member by the release agent application roller includes a pressure contact area formed by contact between the film and the pressure member. The fixing device described.