JP2000315033A - Heat fixing device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of a peeling offset phenomenon and toner accumulated on a pressurizing member side causing soiling of a front surface and a back surface of recording material due to faster speed of a fixing device. SOLUTION: This fixing device is constituted so that the recording material where an unfixed toner image is formed is passed through a nip where a rotational heating body 3 and a pressurizing member 4 are brought into pressurized contact with each other, and then, the unfixed toner image is melt fixed to recording material as a permanent image. In this case, a brush-shaped rotating member 12 that is rotated in contact with the surface of the rotating heating body 3 is provided and this brush-shaped rotating member 12 is rotated with a difference in circumferential speed from the rotating heating body 3 while being impressed with bias.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat fixing device used for a copying machine, a printer, a facsimile, a recording device, and the like using an electrophotographic method, and an image forming apparatus using the heat fixing device.

[0002]

2. Description of the Related Art Conventionally, as a method of fixing an unfixed image on a recording material, a contact heating type heat roller fixing method having good thermal efficiency and safety, and an energy saving type film heating method have been adopted. The heat fixing device of the heat roller fixing method is a heating roller (fixing roller) as a heating rotating body.
And a resilient pressure roller as a pressure rotating body pressed against the roller, the pair of rollers being rotated, and an unfixed image (toner) is placed in a pressure contact nip portion (fixing nip portion) of the roller pair. The heat and elasticity of the heating roller is achieved by introducing a recording material (transfer material sheet, electrostatic recording paper, electrofax paper, printing paper, etc.) as a material to be heated on which images are formed and carried The unfixed toner image is fixed on the recording material surface as a permanent fixed image by heat and pressure by the pressing force of a pressure roller.

Further, a heat fixing device of a film heating type is disclosed in, for example, JP-A-63-313182 and JP-A-2-1
57878, JP-A-4-44075 to JP-A-4-44083, JP-A-4-204980 to JP-A-4-204984, and the like. A heat-resistant film (fixing film) is brought into close contact with a pressure rotating body (pressure roller) and slid and conveyed, and the heat-resistant fixing film is sandwiched between the pressure-contact nip formed by the heating element and the pressure member. The recording material holding the unfixed toner image is introduced and conveyed together with the heat-resistant film, and the unfixed toner image is formed by the heat from the heating body applied through the heat-resistant film and the pressing force of the pressing member. The image is fixed on the transfer material as a permanent image.

In the above-described film heating type heating apparatus, a linear heating element having a low heat capacity can be used as a heating element, and a film having a low heat capacity of a thin film can be used as a heating element.
Shortening of wait time (quick start property) is possible. In this type of heat-fixing method, a driving roller is provided on the inner peripheral surface of the film as a driving method of the fixing film, and the film is driven while applying tension to the film. A method in which the film is driven to rotate relative to the pressing rotator by driving the rotator is known. However, in recent years, the latter pressing rotator driving method is adopted because the number of components can be reduced. Often.

[0005] As a specific example, FIG. 5 shows a sectional configuration of the latter film fixing device driven by a pressure roller. In the figure, the image formed by the toner 9 formed on the recording material 8 includes a release layer 4a and a heat-resistant rubber layer 4b.
A pressure roller 4 having a cored bar 4c supported by a fixing device lower frame 6 ', and a fixing side metal stay 5 pressed down by a pressing means (not shown) provided on the fixing device upper frame 6. Between the cylindrical fixing film 3 and the cylindrical fixing film 3 which is rotated and conveyed along the heater holder 2 also serving as a film guide member together with the rotation of the pressure roller 4 due to the frictional force acting on the interface. The sheet is conveyed to the nip along a fixing guide 7, heated and pressurized by the heater 1 via the fixing film 3, fixed, and discharged along a sheet discharge guide 7 ′.

At this time, the fixing film 3 has a thickness of 100 μm or less, more preferably 40 μmm or less, and 20 μm or less, in order to reduce the heat capacity and improve the quick start property.
m, PTFE, P with heat resistance, mold release and durability
FA, PPS single layer film or base layer film 3c of polyimide, polyamide imide, PEEK, PES, etc.
PTFE, PF with conductive primer layer 3b interposed on the surface
It is composed of a composite layer film in which a release layer 3a made of a fluororesin such as A or FEP is coated or formed into a tube.

In the case of using the fixing film 3 having the three-layer structure, as shown in FIG. 6, a region where the conductive primer layer 3b is exposed at the end of the fixing film is provided, and the position of the opposing position on the surface of the primer layer is adjusted. A conductive rubber ring 4 at the end of the pressure roller
d into the pressure roller core 4a via the resistor 4c,
By pressing the conductive rubber ring 4d against the conductive primer layer 3b under pressure, the primer layer 3b of the fixing film 3 is grounded by resistance. Thereby, the potential of the fixing film 3 is stabilized, and the electrostatic charge is prevented from adversely affecting the charged toner image on the recording material.

Various image forming apparatuses such as a printer and a facsimile using the above-mentioned heat fixing device eliminate the need for preliminary heating during standby due to the high heating efficiency and the rising speed.
It has many advantages such as elimination of waiting time, and in particular, the method of driving a cylindrical film with the conveying force of a pressure roller can be realized at low cost. The introduction to high-speed machines is expected.

In order to realize this high speed, first, naturally, the motor is powered up and the pressure roller 4 is turned on.
In addition to increasing the rotation speed of the fixing film 3 and supplying sufficient thermal energy to the recording material having a short passage time, the fixing temperature is set higher or the pressing force of the pressure roller 4 is increased to increase the heating area. It is necessary to make improvements such as widening the heater substrate and changing the material of the heater substrate and the fixing film 3 to a material having high thermal conductivity.

[0010]

However, when such improvements are made, the following adverse effects are likely to occur in the fixing nip at the same time. A phenomenon occurs in which the toner on the recording material is partially blown to the downstream side in the transport direction of the recording material, and this phenomenon may worsen as the recording speed is increased (hereinafter, this phenomenon is referred to as a phenomenon). This phenomenon is referred to as a “rear toner scattering” phenomenon). The following mechanism can be considered as a cause of the occurrence of the “rear toner scattering” phenomenon. That is, in the fixing nip portion,
Since the recording material to be fixed contains a certain amount of moisture even under a normal environment, water vapor is generated by heating in the fixing nip portion. Therefore, steam is strongly blown out in the front-rear direction of the nip portion in search of an escape place.

At this time, since the conveying speed of the recording material is also increased at the same time, at the entrance of the fixing nip, the wind speed is obtained by synthesizing the conveying speed of the recording material with the speed of the steam blown out to the unfixed toner on the recording material. Water vapor is sprayed, and the toner has a relatively weak adhesion to the recording material like the toner on the image surface layer, and a part of the toner susceptible to the airflow on the surface is blown backward by the wind pressure. It is considered something. Although this phenomenon is greatly affected by the electrical resistance and surface properties of the recording material and the type of additive, it is most likely to occur in toner images having a pattern perpendicular to the recording material conveyance direction such as a horizontal line. This is a phenomenon that becomes worse as the recording speed increases.

Such a phenomenon occurs even in a conventional heat roller type apparatus when the speed is increased. As a measure for suppressing such a phenomenon, the thermal condition cannot be relaxed due to the necessity of securing the fixing property. A method of increasing the electrostatic adhesion of the toner to the recording material has been considered.

In addition to the above-mentioned adverse effects, a phenomenon called offset, in which the toner on the recording material adheres to the surface of the fixing-side rotating body with the increase in speed and later transfers to another image area, also tends to be deteriorated. Several mechanisms can be considered as factors for the occurrence of the offset phenomenon and the deterioration of the level. One of the mechanisms is a decrease in the fixing property. This is because simply increasing the speed reduces the time required to pass through the fixing nip, making it difficult to apply a sufficient amount of heat to the recording material. The amount of toner is insufficient, and the fused toner on the surface layer adheres to the fixing rotating body side with the heat source by adhesive force. Especially when the unevenness of the recording material surface is rough and large, heat and pressure do not sufficiently spread to the toner in the concave portion. Therefore, an offset due to this factor easily occurs.

Another mechanism is an electrostatic factor. This is because it is necessary to design the fixing-side rotating body surface to have a certain level of resistance in order to prevent leakage of the transfer charge of the recording material. In the case of continuous conveyance, unnecessary charging occurs on the surface of the fixing-side rotator, and an offset occurs when the polarity becomes opposite to that of the toner that attracts the toner. In particular, when the resistance of the fixing-side rotator is high, the toner is attached to the surface of the fixing-side rotator due to the peeling charge generated when the trailing end of the recording material passes through the fixing nip and is separated from the surface of the fixing-side rotator. Is formed, and a phenomenon called separation offset occurs in which the toner is adsorbed in the next fixing step.

Further, another factor of worsening the offset is a shortage of transfer charge due to a high speed. This occurs when, in the transfer section, the transfer charge to be applied per unit area of the back surface of the recording material per unit time cannot be overtaken by increasing the passing speed of the recording material. It depends on the influence of durability deterioration.

If these factors of the deterioration of the fixing property are overlapped, as a result, a sufficient force for holding the toner on the recording material cannot be obtained, the toner is offset to the fixing rotating body side, and the toner is eventually pressed. There is a problem that it is also accumulated on the side and causes a new problem of stain on the front and back surfaces of the recording material.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has a polarity opposite to that of a conventionally generated heating element surface which is generated on a heating element surface while suppressing the rear toner scattering phenomenon and offset. Cleaning of fine powder (paper powder, toner, etc.)
It is an object of the present invention to provide a heat fixing device that can also suppress contamination on the surface of a heating roller and stably maintain good image quality throughout the life of the fixing device.

It is another object of the present invention to obtain an image forming apparatus which performs a high quality image forming operation by a smooth fixing operation by applying the heat fixing device.

[0019]

According to the present invention, there is provided a heat fixing apparatus and an image forming apparatus having the following constitution.

(1) The recording material on which the unfixed toner image has been formed is passed between the nips where the rotary heating element and the pressing member are in pressure contact with each other, and the unfixed toner image is permanently imaged on the recording material. A heating and fixing device for melting and fixing, a brush-shaped rotating member that rotates in contact with the surface of the rotary heating member, and the brush-shaped rotating member is rotated while providing a peripheral speed difference with the rotary heating member while applying a bias voltage. A heating and fixing device.

(2) The heat fixing device according to (1), further comprising a cleaning member for cleaning the brush-like rotating member.

(3) The object to be cleaned generated by the cleaning member is
(1) The heat fixing device according to (1), further including a cleaning guide member that is conveyed downstream of the nip in the recording material discharge direction.

(4) An image forming apparatus comprising: an image forming means for forming and carrying an unfixed toner image on a recording material; and a heat fixing means for heating and fixing the unfixed toner image formed and carried on the recording material to the recording material. An image forming apparatus, wherein the heat fixing unit is the heat fixing unit according to any one of (1) to (3).

[0024]

An embodiment of the present invention will be described below with reference to the accompanying drawings.

Embodiment 1 FIG. 1 is a cross-sectional view of a heat fixing device according to Embodiment 1 of the present invention. The same parts as those of the conventional device shown in FIG. In the figure, reference numeral 12 denotes a brush-shaped rotary cleaning means (hereinafter, referred to as a cleaning brush) that rotates in contact with the surface of the heating body with a speed difference, and cleans and charges the surface of the heating body. This cleaning brush 12 has a diameter of 5
mm of stainless steel is used as a cored bar 12a, and a conductive fiber 12b is pile-woven around the cored bar 12a, and then the fiber length is cut to 5 mm and the diameter is 16 mm.
mm rotary type. The conductive fibers 12b are provided with conductivity by dispersing carbon in aramid fibers. The thickness of each fiber is 10 to 15 μm, and the resistance per fiber is 10 ⁹ Ω. The density of this fiber is 155 fibers / m ² . Further, as the conductive fiber, a metal brush made of SUS or the like and coated with Teflon may be used.

If the resistance of the cleaning brush 12 is low, there is a danger that a leak will occur when the film 3 has a pinhole or the like. If the resistance is too high, the film 3 cannot be uniformly charged. Is desirable. -1 KV from the power supply E is applied to the cored bar 12a.
Is applied and the film surface is about -500V
Can be charged. The cleaning brush 12 is softly nipted into the surface of the heating body by about 2 mm and comes into contact therewith. The cleaning brush 12 rotates in the opposite direction at the same peripheral speed as the film transport speed without obstructing the transport of the film 3 on the surface of the heating body.
An auxiliary roller 1 serving as a means for ensuring that the film 3 and the cleaning brush 12 are in contact with each other on the inner surface side of the film 3.
2 'is provided.

With the above configuration, paper dust adhered to the film surface and a small amount of offset toner can be removed and the film surface can be cleaned while suppressing the rear toner scattering and the occurrence of offset. As long as it could be used, good fixed image quality could be maintained without causing contamination of the film or the pressure roller.

The result of comparison between the first embodiment and the comparative examples 1 and 2 provided with a means for charging the film surface is shown below.

In Comparative Example 1, as shown in FIG. 7, a bias was applied from inside the film as a means for charging the film surface. That is, a bias voltage of -500 V is applied to the conductive primer layer 3b of the film 3 shown in FIGS. 5 and 7 to charge the film surface.

In Comparative Example 2, as shown in FIG. 8, a bias voltage of -1 KV was applied from a power source E to a charging roller 120 made of rubber. The charging roller 120 is made of aluminum core 1
The driven roller 12 has a roller shape in which the film 3 is sandwiched between the driven roller 12 and the roller 20a.
With 0 ′, the film 3 is configured to be softly driven and contact-rotated with the film 3.

The evaluation for comparing the pressure roller dirt and the film dirt was performed by using a printer having a printing speed of 16 sheets / min (A4 paper) and a recording paper conveying speed of 94.2 (mm / sec). Printing was performed and the image was evaluated.
The image evaluation was performed on the backscatter phenomenon and the offset. Further, by performing the durable paper passing (continuously transporting the recording material while a normal image is obtained), the degree of contamination of the pressure roller 4 and the film 3 is compared with Comparative Example 1, Comparative Example 2, and Embodiment 1. Was compared.

The dirt on the film 3 and the pressure roller 4 was evaluated using a recording material having a large amount of paper dust, which was disadvantageous for fixing property.
Intermittent printing was performed in a low-temperature and low-humidity environment of 10 ° C. using an image pattern in which offset was likely to occur, and dirt due to durability was observed. As a recording material for evaluation, CanonPa containing a large amount of calcium carbonate during transport durability was used.
Using a per (manufactured by Neusitra) A4 size 80 g / m ² , the degree of contamination was observed, and the results of level evaluation are shown in Table 1 below. Note that the levels in the table are a level having no O problem, a △ allowable level, and a level having x problem.

[0033]

[Table 1]

According to the results shown in Table 1, in Comparative Example 1, 10
From around K sheets, pressure roller contamination and film contamination reach problematic levels. Rubber charging roller 120
In Comparative Example 2 using, dirt reaches a problematic level from around 100K sheets. On the other hand, in the first embodiment using the brush-like cleaning ink brush 12,
It can be seen that a satisfactory level can be maintained up to 0K sheets. The charging of the film 3 can suppress the rear toner scatter and the offset phenomenon in any of Comparative Example 1, Comparative Example 2, and Embodiment 1. However, when the paper is durably passed, paper dust having the opposite polarity to the film potential is generated. It adheres and gradually covers the surface.

By charging the surface of the film, scattering of the rear toner and offset are improved, but fine powder having a polarity opposite to that of the toner (paper powder such as calcium carbonate, talc, kaolin, etc.) is easily attached electrostatically. The paper dust contained in these recording materials is liable to be charged due to friction in the conveyance path when the recording material is conveyed, and calcium carbonate becomes + (plus), and talc and kaolin become-(minus). ) Is known to strongly charge itself.

Paper powder having a polarity opposite to that of the heating element (film) easily adheres to the charged surface of the heating element, and when a certain amount of the paper powder accumulates on the film, the releasability of the heating element surface is lost and toner is removed. Is easy to adhere. Once the toner is transferred onto the film, the amount of toner offset with the toner as a nucleus increases.

The toner transferred onto the film 3 is as follows:
The transfer also occurs to the pressure roller 4 having a lower temperature, and both the film 3 and the pressure roller 4 are soiled. In other words, when the surface of the heating element is charged to the same polarity as the toner, the offset is initially good, but when the paper is passed, the film 3 in Comparative Example 1, which has no means for cleaning the film surface, is used.
In addition, the pressure roller 4 is soiled with toner. In Comparative Example 2 having cleaning ability and Embodiment 1, the film surface can be stably charged for a long period of time.

In Comparative Example 1, since the conductive primer layer 3b inside the film is biased, it becomes difficult to uniformly charge the surface if paper dust or the like adheres to the film surface. However, in Comparative Example 2 and Embodiment 1, charging can be performed by directly contacting the film surface, so that the film surface can be uniformly charged as compared with Comparative Example 1.

As described above, in Comparative Example 1, since the paper powder attached to the film 3 has the opposite polarity to the toner, the toner is sucked. Once the toner adheres to the film 3, the toner attached to the film 3 is increased by using the toner as a nucleus,
This caused film contamination and pressure roller contamination.

In Comparative Example 2, the charging roller 120 made of rubber was used.
Is charged by the driven contact of the film 3 so that even if paper powder of the opposite polarity once adheres to the fixing nip, the paper powder and the film surface adhered by passing through the charging roller 120 are brought to a desired potential. Since the toner can be charged, it is possible to suppress the toner from adhering to the film 3 as in Comparative Example 1.

In the first embodiment, the cleaning brush 12
As in Comparative Example 2, even if paper powder of the opposite polarity once adheres to the fixing nip, the paper dust and the film surface adhered by passing through the cleaning brush 12 as in Comparative Example 2. Can be charged to a desired potential. By using the cleaning brush 12, a function of cleaning paper dust and slight offset toner attached to the film surface can be provided. The function of the cleaning brush 12 for cleaning the film surface is also provided in the rubber charging roller 120 of Comparative Example 2 which is driven and rotated in contact with the film. However, by using the cleaning brush 12, the film surface can be further cleaned and the charging is performed. Therefore, as compared with Comparative Example 2, film contamination and pressure roller contamination can be further suppressed.

In the first embodiment, the pressure roller dirt gets worse and the offset gets worse every 200K sheets.
This evaluation uses recording paper with a lot of paper dust, performs intermittent printing, and prints an image in which offset is likely to occur in a low humidity environment. Not considered a level.

Embodiment 2 FIG. 2 is a cross-sectional view of a heat fixing device according to a second embodiment of the present invention. The same parts as those of the device shown in FIG. In the drawing, reference numeral 15 denotes a roller diffusion member 15 for cleaning paper dust and toner captured by a cleaning brush 12 which is a film cleaning means. As the roller diffusion member 15, a Mylar or SU having a thickness t of about 0.5 is used.
An S plate, a phosphor copper plate or the like is suitable. The roller diffusion member 15 is attached to the outer circumferential surface of the cleaning brush 12 by 0.5
It is bitten by about mm and brought into contact.

The paper dust and the offset toner once cleaned and held by the cleaning brush 12 are diffused and released in the vicinity of the roller diffusion member by the contact of the roller diffusion member 15, and the cleaning brush 12 can be freshened.

With such a configuration, the cleaning brush 12 can be kept in a freshly cleaned state without being contaminated with toner or paper dust, and the function of cleaning the film 3 is a long-term service life of the fixing device. Can be kept over. As a means for adsorbing and capturing paper dust and toner on the cleaning brush 12 by the roller diffusion member 15, an electrode plate 16 having a polarity opposite to that of the toner or paper dust is provided near the outer peripheral surface of the cleaning brush 12. . Paper dust and offset toner on the film by the cleaning brush 12 are scattered from near the contact nip between the cleaning brush 12 and the film 3 toward the downstream side of the rotation of the cleaning brush. An electrode plate 16 is provided on the downstream side of the nip n1 for the scattered paper powder and toner, and can be electrostatically captured by the electrode plate 16, so that the cleaning brush 12 can be freshened.

With such a configuration, the cleaning brush 12 can always maintain a freshly cleaned state without being stained with toner or paper dust.

Hereinafter, the results of performance comparison between the configurations of Comparative Example 1 and Comparative Example 2 in FIGS. 7 and 8 and the configuration of Embodiment 2 shown in FIG. 2 will be described. The evaluation conditions and items are the same as those in the first embodiment.

[0048]

[Table 2]

As is clear from the results in Table 2, in the second embodiment, a brush material is used for the roller for cleaning and charging the surface of the film, and the function of cleaning the film is the same as in the first embodiment. It can be seen that the progress of the film and the pressure roller stain is delayed as compared with Comparative Example 1 because the long-term fixing device life can be maintained.

Embodiment 3 FIG. 3 shows a configuration in which the paper dust and offset toner separated from the cleaning brush 12 are guided to the downstream side of the fixing nip by the cleaning guide 17 and returned to the recording material conveyance path. The cleaning guide 17 is provided on the downstream side of the fixing nip, and discharges the paper powder and the offset toner captured and collected from the cleaning brush 12 through the recording material in small amounts so as not to affect the image quality.

By adopting such a configuration, a device for collecting and capturing the paper dust and the offset toner cleaned from the film surface becomes unnecessary, and the device can be reduced in size and simplified. Even if a large amount of paper dust or offset toner is generated, these are successively returned to the recording material or to the conveyance path of the recording material, so that the function of cleaning the film can be maintained satisfactorily. Images can be obtained over a long period of time.

Embodiment 4 FIG. FIG. 4 shows the first embodiment.
To the heat fixing device 56 according to the third embodiment.
1 is a configuration diagram illustrating an image forming apparatus to which the present invention is applied. In FIG. 4, reference numeral 51 denotes a photosensitive drum (image forming means),
A photosensitive material such as amorphous Se or amorphous Si is formed on a cylindrical substrate such as aluminum or nickel. The photosensitive drum 51 is driven to rotate in the direction of the arrow, and the surface thereof is first charged with a charging roller 52 as a charging device.
(Image forming means). Next, scanning exposure is performed by a laser beam 53 (image forming means) that is ON / OFF controlled according to the upper part of the image, and an electrostatic latent image is formed. This electrostatic latent image is developed and visualized by the developing device 54 (image forming means). As a developing method, a jumping developing method, a two-component developing method, an FEED developing method, or the like is used.
Image exposure and reversal development are often used in combination.

The visualized toner image is transferred from the photosensitive drum 51 onto a recording material 58 conveyed at a predetermined timing by a transfer roller 55 (image forming means) as a transfer device. At this time, the recording material 58 is nipped and conveyed by the photosensitive drum 51 and the transfer roller 55 with a constant pressing force. The recording material 58 to which the toner image has been transferred is conveyed to the heat fixing device 56 and fixed as a permanent image. On the other hand, the transfer residual toner remaining on the photosensitive drum 51 is removed from the surface of the photosensitive drum 51 by the cleaning device 57. Reference numeral 59 denotes a cutter for cutting the recording material 58.

[0054]

As described above, according to the present invention, there is provided a brush-like rotating member which rotates in contact with the surface of the rotating heating body, and the rotating heating body and the peripheral speed are applied while applying a bias voltage to the brush-like rotating member. Since the rotation heating unit is configured to be rotated while providing a difference, it is possible to reliably clean and charge the surface of the rotary heating body. In other words, the rotation direction and speed of the brush can be freely varied and set without suppressing the film conveyance force due to the frictional force with the film surface.
In addition, by rotating the contact in the direction opposite to the film transport direction, it is possible to increase the chance of contact with the film surface,
When using a recording material that easily generates paper dust, or when a large amount of offset toner is generated due to the high-speed operation of the device, it is possible to remove paper dust, toner, and other deposits on the film surface. became.

As a result, at the same time as countermeasures against the rear toner scattering phenomenon and offset, fine powder (paper powder, toner, etc.) having a polarity opposite to that of the surface of the heating element, which has been conventionally generated, adheres to the surface of the heating element.
To clean the surface of the heating element and maintain good releasability on the surface of the heating element.
As long as it functions as a fixing device, good image quality can be stably maintained.

Further, according to the present invention, since the cleaning member for cleaning the brush-like rotating member is provided, the brush-like rotating member gradually cleans the paper powder, the offset toner and the like on the surface of the heating body. It is possible to provide a heat fixing device which prevents the performance of cleaning the surface of the heating element from being gradually deteriorated and maintains stable and good image quality as long as it has a fixing function.

Further, according to the present invention, the object to be cleaned generated by cleaning the brush-like rotating member is conveyed to the downstream side of the fixing nip portion in the recording material discharging direction. Even when a large amount of objects to be cleaned such as paper dust and offset toner accumulated in the rotating cleaning means in contact with the cleaning material can return paper dust and offset toner to the downstream side in the transport direction of the recording material and the fixing nip, It is possible to provide a heat-fixing device that can stably maintain a good image quality as long as it has a fixing function without providing a device for capturing an object to be cleaned, and can simplify and reduce the size of the device.

Further, according to the present invention, there is an effect that an image forming apparatus which performs a high quality image forming operation by a smooth fixing operation by applying the heat fixing device can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a heat fixing device according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a heat fixing device according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a heat fixing device according to a third embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of an image forming apparatus of the present invention to which any one of the heat fixing devices according to the first to third embodiments is applied.

FIG. 5 is a cross-sectional view of a conventional heat fixing device using a film heating method.

FIG. 6 is a diagram showing the relationship between a cylindrical fixing film and a pressure roller.

FIG. 7 is a cross-sectional view of a conventional heat fixing device showing a method of charging a film surface.

FIG. 8 is a sectional view of a conventional heat fixing device using a charging roller as a method for charging a film surface.

[Explanation of symbols]

3 fixing film (rotary heating element), 4 pressure roller (pressure member), 12 cleaning brush (brush-shaped rotating member), 15 diffusion member (cleaning member), 17 cleaning guide (cleaning guide member), n1 nip , 51 photosensitive drum (image forming means), 52 charging roller (image forming means), 53 laser beam (image forming means), 54 developing device (image forming means), 55
Transfer roller (image forming means), 56 heat fixing device, 58 recording material.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masami Takeda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. F-term (reference) 2H033 AA08 AA09 BA13 BA49 BA54 BA57

Claims (4)

[Claims] 1. A recording material on which an unfixed toner image is formed is passed through a nip where a rotary heating element and a pressing member are pressed against each other, and the unfixed toner image is formed as a permanent image on the recording material. In the heat fixing device for melting and fixing,
A heating and fixing device, wherein a brush-like rotating member that rotates in contact with the surface of the rotating heating body is provided, and the brush-like rotating member is rotated with a peripheral speed difference from the rotating heating body while applying a bias voltage. . 2. The heat fixing device according to claim 1, further comprising a cleaning member for cleaning the brush-like rotating member. 3. The heat fixing device according to claim 1, further comprising a cleaning guide member configured to convey an object to be cleaned generated by the cleaning member downstream of the nip in a recording material discharging direction. 4. An image forming apparatus comprising: an image forming unit for forming and carrying an unfixed toner image on a recording material; and a heat fixing unit for heating and fixing the unfixed toner image formed and carried on the recording material to the recording material. 4. The image forming apparatus according to claim 1, wherein the heat fixing unit is the heat fixing device according to any one of claims 1 to 3.