JPH06149114A - Fixing device, cleaning device and fixing roller - Google Patents

Abstract

PURPOSE:To obtain a fixing device provided with a separating member not damaging a rotary member and winding a recording material onto the rotary member, but further easily controlling a gap by forming the part where the separating member is in contact with the rotary member with fluororesin. CONSTITUTION:In a separating pawl 7 for separating the recording material P from a fixing roller 1, the contract part 702 consisting of a PTFE resin tip is force-fitted and adhered to a separating pawl main body 701 consisting of polyimide resin. The fixing roller 1 has the releasing layer 101 of a PFA tube on the surface layer. The margin region of the leading edge of the recording material P is carried with 300-500mum gap from the fixing roller 1 by the stiffness of the recording material P. Therefore, it is unnecessary that the tip of the separating pawl 7 is always in contact with the fixing roller 1 and when the gap of the fixing roller 1 with respect to the tip of the separating pawl 7 is controlled <=300mum, the recording material P can be separated. The gap is controlled by the contact part 702.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure type or heat pressure type fixing device mounted on an electrophotographic printer such as a laser beam printer or a copying machine, a cleaning device used for the fixing device, and a fixing roller. Is.

[0002]

2. Description of the Related Art FIG. 4 is a vertical sectional view of a specific example of the fixing device. In FIG. 4, the fixing roller 1 on the upper side is a hollow cored bar made of aluminum, iron or the like, and a heater 2 such as a halogen lamp is placed inside the hollow cored bar. The heater 2 heats the fixing roller 1. . Reference numeral 101 denotes a release layer for improving the surface property of the fixing roller 1 , and a fluororesin coating or a tube is preferably used.
The pressure roller 3 on the lower side is a core metal 304 made of iron or stainless steel.
The outer periphery of the elastic body 30 having releasability such as silicone rubber
It is coated with 5. The fixing roller 1 and the pressure roller 3 are brought into contact with each other with a predetermined pressure by an urging means such as a spring (not shown), and are rotationally driven in the arrow direction.

[0003] 6 is a temperature sensing element such as a thermistor in contact with the surface of the fixing roller 1, for detecting the surface temperature of the fixing roller 1. The temperature control circuit controls the energization of the heater 2 according to the temperature detected by the temperature sensitive element 6, and the surface temperature of the fixing roller 1 is automatically controlled to a predetermined thermal fixing temperature. Denoted at 7 is a separation claw for separating the recording material P from the surface of the fixing roller 1 , and the tip edge portion is arranged so as to be in contact with the surface of the fixing roller 1 with an appropriate pressing force. 8 is a cleaner such as a felt obtained by pressure contact with the fixing roller 1 side, the fixing roller 1 toner tc or paper dust adhering to the surface like拭掃removed. Reference numeral 9 denotes a bottom plate made of a metal material of the fixing device, and 10 and 11 denote recording material inlet guides and outlet guides, which are attached to and supported by the bent entire surface wall of the bottom plate 9 upward.

In the fixing device as described above, the recording material P that has entered through the inlet guide 10 is guided to the nip portion between the fixing roller 1 and the pressure roller 3 which are in pressure contact with each other and are rotationally driven. In the process of passing through the nip portion, the unfixed toner image ta is fixed on the recording material P as a permanently fixed image by heat and pressure.

After that, the recording material P, which has passed through the nip portion of the rollers 1 and 3 and has undergone image fixing, has its leading end separated from the surface of the fixing roller 1 by the separating claw 7, and goes out of the fixing device through the exit guide 11. Is discharged.

As described above, the separating claw is an indispensable member in the apparatus for fixing by heating and pressurizing, and generally has a sharp tip as shown in FIG. 5
As shown in (b), the leading end is brought into contact with the fixing roller 1 to separate the recording material.

Therefore, the separation claw 7 is required to have a tip precision for surely separating the recording material P, and is generally a heat resistant and high hardness material such as polyimide (PI) or polyamide imide (PAI). Material such as is used. Further, when the releasing property of the separating claw is emphasized, the tip surface may be coated with a fluororesin, but the fluororesin having excellent releasing property has low hardness, which is inconvenient for forming a sharp tip portion. Is.

Next, another conventional example will be described. The fixing device permanently fixes the toner image carried on the recording material onto the recording material and fixes it, but conventionally, the toner image on the recording material is heated and pressed through a roller to record the toner image. A heat roller type that is melted and fixed onto a material is often used.

This heat roller type fixing device includes a pair of fixing rollers including a heating roller having a heat source such as a halogen lamp and rotating in a fixed direction, and a pressure roller rotating in pressure contact with the heating roller. The toner image is fixed on the recording material by passing the recording material carrying the toner image between the fixing rollers.

In order to obtain a good image in such a fixing device, it is extremely important to control the surface temperature of the heating roller to a predetermined constant value. This is because if the surface temperature of the heating roller is too low, the toner image is insufficiently fixed (the toner image is not sufficiently fixed on the recording material and is easily separated), and if it is too high, offset (a part of the toner image is transferred to the heating roller). This is because the phenomenon of welding) occurs.

Therefore, conventionally, a temperature detecting element is brought into contact with the surface of the heating roller to detect the temperature of the surface, and the control circuit controls the heat source based on the detected temperature.
The surface temperature of the heating roller is controlled to a predetermined constant value.

The temperature detecting element (hereinafter referred to as NTC)
Is usually placed on a silicone sponge, etc.,
This is wound with a tape made of heat-resistant polyimide or the like, and is arranged so that the surface of the tape comes into contact with the surface of the heating roller and also contacts the surface with a constant pressure.

This is because if the NTC becomes slightly floating from the roller surface, the surface temperature of the heating roller will be controlled to a higher value, and other problems will occur.

However, when the number of sheets of recording material carrying a toner image increases, the surface of the heating roller in the portion in contact with the NTC is scraped by sliding and the roller is scratched. Then, there are problems such as roller stains in the scratched portion, image fixing failure, and image stains.

Further, in consideration of the releasability of the toner, the surface of the heating roller is often coated with a fluororesin, but if the surface of the heating roller is scraped off, the toner easily adheres to the portion and is in contact with the surface. Contamination on the surface of the tape significantly increases and the amount of abrasion increases, which repeats a vicious cycle. This adversely affects the image stains on the recording material and also impairs the temperature control of the roller, thereby significantly impairing the durability of the fixing device.

FIG. 17 is a diagram schematically showing such abrasion of rollers by the NTC. In FIG. 17, NTC20
In No. 2, beads 205, which are temperature detecting elements, are arranged in the center of a silicone sponge on a substrate 203, and the beads 205 are wound with a polyimide tape 206. As can be seen from this figure, the portions corresponding to the edges of the beads 205 and the polyimide tape 206 are respectively 20 on the surface of the heating roller.
Roller scratches as shown by 5a, 206a, and 206b are generated.

Therefore, conventionally, in order to prevent the roller from scraping the bead portion, a concave depression is provided in the silicone sponge, or the beads are sandwiched between aluminum foils.
It has been proposed that a phosphor bronze sheet metal is arranged on beads and then a tape is wrapped around the beads to suppress the influence of abrasion by the beads.

Next, another conventional example will be described. Figure 2
FIG. 1 is a diagram showing an example of a conventional fixing device using a cleaning pad. In FIG. 21, the unfixed toner image 401
The recording material 402 carrying the sheet is guided to the fixing device 403, enters the nip portion N of the fixing roller 405 having the heater 404 and the pressure roller 406 in the fixing device 403, and pressurizes at the nip N. The unfixed toner image 401 is heated and fixed on the recording material 402. As described above, since the toner image 401 comes into contact with the fixing roller 405, a part of the toner image 401 is transferred to the fixing roller 405 and stains a subsequent image, which causes a so-called offset phenomenon.
For that purpose, a cleaning pad 407a of a cleaning device 407 as shown in the figure is brought into contact with the fixing roller 405 to remove the offset toner 408, and the fixing roller 405 is cleaned to prevent the offset phenomenon. There is.

Further, in the conventional apparatus shown in FIG. 21, the cleaning device 407 is constructed by a method such as bonding a cleaning pad 407a such as felt to the lower part of the heat-resistant plastic 407b as shown in FIG. 22 (a). Then, the fixing device upper cover 410 as shown in FIG.
Mounted in the hole of the fixing roller 4 from above with a spring or the like.
Pressurized at 05. And the cleaning pad 4
When 07a is soiled with the offset toner, it is replaced with a new cleaning device.

Next, another conventional example will be described with reference to FIG. In FIG. 27, 501 is a hollow pipe-shaped fixing roller in which a heater 503 is arranged. The surface temperature of the fixing roller 501 is measured by the temperature sensor 5
04, and a controller (not shown) turns the heater 503 on and off to keep it constant. Further, 502 is a pressure roller, and the fixing roller 50
1 is pressed by urging means (not shown) to nip N
Is formed. Therefore, when the fixing roller 501 is driven in the direction of the arrow, the pressure roller 502 is driven to rotate, and the paper sheet 505 on which the unfixed toner image 506 is placed is nipped and conveyed in the nip N and heated in the nip N. By applying pressure, a permanently fixed toner image is obtained.

In the example shown in FIG. 27, the unfixed toner image 50
6 is negatively charged, and by disposing the diode 507 and the diode 508 in the direction shown in the figure, the toner image 506 is electrostatically fixed in the nip N by the fixing roller 501.
It is prevented from being sucked into. In this way, the nip N
By appropriately generating an electric field in the inside, the unfixed toner image 506 is prevented from transferring to the surface of the fixing roller 501, and the offset phenomenon that stains the subsequent non-image portion is also eliminated, so that the cleaning unit for the fixing roller 501 is removed. Has the advantage that it is unnecessary. As such an electric field generating means, a bias power supply can be used instead of the diode.

On the other hand, in the above apparatus, the pressure roller is also provided with an offset measure. FIG. 28 shows the pressure roller 5
02 of the elastic layer 52 on the core metal 521.
2 is arranged, and a fluororesin layer 524 is arranged via an adhesive layer 523. The fluororesin layer 524 has a high releasability, and is used for the purpose of preventing the toner on the surface layer from being contaminated even during long-term use.

[0023]

However, according to each of the above conventional examples, there are the following problems. First, according to the conventional example shown in FIG. 4, the separating claw made of the conventional high hardness material damages the surface of the rotor by the sharp tip contacting with the rotor and impairs the releasability of the rotor. There were problems such as offsetting and winding the recording material.

Further, recently, in consideration of resource saving, cost reduction, and maintainability, a fixing device having no rotating member cleaning member is desired, and in such a case, the toner accumulated on the separating claw is desired. There is a problem that the lumps are transferred from the separating claws to the rotating body due to mechanical or accumulation saturation and adhere to the rotating body to stain the recording material. Therefore, in such a case as shown in FIG. 6, an apparatus provided with a non-contact separation plate 705 has been proposed. However, in such an apparatus, if the gap with the rotating body is large, the separation is defective, and the recording is performed on the rotating body. There is a problem that the material is wrapped around, and there is a problem that in order to reduce the gap, it is very difficult to improve the accuracy of the surface of the separating plate facing the rotating body and to manage the gap.

Further, in the case where image stains or the like occur due to damage to the surface of the fixing roller due to the separating claw as described above, the conventional performance is obtained even though the original performance can be obtained again by replacing the fixing device or the fixing roller. It was difficult to identify what was causing the problem only from the output image, and it was necessary to spend a lot of time and effort.

Although the fixing device is guaranteed to have a minimum service life, it can be used nearly twice as long depending on the condition of use, and the maintenance method of replacing the fixing device when it reaches the minimum service life is It is not preferable from the viewpoint of effective use. On the other hand, when the end of the life is approached, the problem often becomes worse gradually, and there is a problem that it is difficult for the user to obtain an opportunity to replace the fixing device.

Further, according to the conventional example shown in FIG. 17, since the amount of abrasion of the edge portion of the tape is relatively small, no conventional measures have been taken. In order to provide a fixing device having higher durability, it is necessary to eliminate the scraping of this portion.

Further, according to the conventional example shown in FIGS. 21 and 22, when the cleaning device is replaced with a new one, the offset toner accumulated on the surface of the fixing roller corresponding to the hole of the fixing device upper cover 410 is removed. It is necessary to clean it. Therefore, conventionally, a new cleaning device 4
A pad 412 was attached to the end portion of 07 by a tape 411 as shown in FIG. Then, after cleaning the offset toner, paper dust, and the like accumulated in the mounting portion of the cleaning device 407 by the end pad 412, the tape 411 is peeled off, the end pad 412 is removed, and the cleaning device 407 is fixed to the fixing device upper cover 410.
It was attached to the hole of. As described above, the end pad 412 must be removed after cleaning when the cleaning device is replaced, and the operation is complicated. In addition, the cost is disadvantageous in that the end pad 412 is separately provided.

Further, according to the conventional example shown in FIG. 28, the amount of toner once attached to the fixing roller 501 is invisible to a small amount per sheet, but a large number of sheets are used. When the paper is passed, the fluororesin layer 524 of the pressure roller 502
After being accumulated on the surface, there was a case where the surface layer was so heavily contaminated as to be covered with the toner 506. This is the nip N
It is considered that the toner 506 once attached to the fixing roller 501 is accumulated on the pressure roller 502 by the action of the electric field inside.

Further, paying attention to the cross-sectional shape of the pressure roller 502, FIG. 29 shows the case where the coefficient of thermal expansion of the elastic layer 522 is larger than the coefficient of thermal expansion of the surface fluororesin layer 524 when heated. As described above, it has been found that the straight shape, which is originally straight, has a larger diameter at the central portion than at the end portions and has a crown shape, which causes wrinkles in the paper sheet 505. This is a remarkable phenomenon especially when the elastic layer 522 is a sponge-like elastic body containing a large amount of air.

A first object of the present invention is to solve the above-mentioned problems and to provide a separating claw that does not damage the rotating body, does not wind the recording material around the rotating body, and easily manages the gap. It is to provide a fixing device.

A second object of the present invention is to solve the above-mentioned problems, and when the surface of the fixing roller is damaged by the separating claw, appropriately notify the fixing roller replacement time to effectively use the apparatus. An object of the present invention is to provide a fixing device that can perform

A third object of the present invention is to solve the above-mentioned problems and to eliminate the abrasion of the roller due to the edge of the tape wound around the member abutting against the fixing roller such as a safety device such as NTC or thermoswitch. , To provide a fixing device having a long life.

A fourth object of the present invention is to solve the above-mentioned problems and to provide a low-cost cleaning device which can be easily cleaned at the time of replacement without separately providing an end pad of the cleaning device. .

A fifth object of the present invention is to solve the above problems and to provide a fixing roller capable of preventing the adhesion of toner to the surface of the pressure roller and the generation of wrinkles in the paper sheet. is there.

[0036]

According to the first invention of the present application,
The first purpose is to provide a rotating member for sandwiching and conveying a recording material carrying an unfixed developer image, and fixing the unfixed developer image on the recording material by fusion, and a recording material sandwiching portion of the rotating member. Also in the fixing device, which is disposed in front of the recording material in the conveying direction and includes a separating member for separating the recording material from the rotating member, the separating member is configured to come into pressure contact with the rotating member with a predetermined pressing force. It is provided, and it is achieved by forming at least the contact portion with the rotating member from a fluororesin.

According to the second invention of the present application, the second object is to sandwich and convey a recording material having surface layers to be pressed against each other and carrying an unfixed developer image, In a fixing device provided with a fixing means for melting and fixing the unfixed developer image on the recording material, the surface layer of the fixing means, which is in contact with the unfixed developer image on the recording material, is made of a conductive material. It is formed so as to cover the recording material and the conductive member so as to cover the member, and means for supplying a voltage to the conductive member, means for detecting the voltage, and voltage detected by the means are predetermined. And a control means set so as to judge that the surface layer is worn or damaged when the surface layer is lower than the reference value.

Further, according to the third invention of the present application, the third object is to provide a fixing roller containing a heat source, a fixing roller disposed so as to contact the surface of the fixing roller, and covered with a tape member on the substrate. In a fixing device provided with a held temperature detecting element, the tape member is achieved by at least both end sides in the axial direction of the fixing roller in the area in contact with the fixing roller surface being away from the fixing roller surface. It

Further, according to the fourth invention of the present application, the fourth object is to apply at least one of the pair of rotating bodies which sandwiches and conveys the recording material carrying the unfixed developer image. In a cleaning device provided with a cleaning member disposed so as to be in contact with each other and a supporting member for the cleaning member, the cleaning member is extended to a non-contact position with the rotating body and attached to the supporting member. Be achieved by

Further, according to the fifth invention of the present application, the fifth object is to provide a release layer on the surface and an elastic layer below the release layer, which is directly or indirectly heated by a heat source. In the fixing roller according to the present invention, the release layer on the surface is formed of a member having a lower coefficient of thermal expansion or a higher coefficient of thermal contraction than the elastic layer, and is attached so as to cause wrinkles on the surface when not heated. Be achieved by

[0041]

According to the first invention of the present application, since the contact portion of the separating member with respect to the rotating member is formed of fluororesin, the releasing property of the surface can be maintained for a long period of time without damaging the surface of the rotating member. Secure. As a result, dirt such as offset toner does not adhere to the rotating member, and dirt such as offset toner does not adhere to the separating member.
Separation performance does not deteriorate.

Further, according to the second aspect of the present invention, the surface layer of the fixing means for nipping and conveying the recording material, which is in contact with the unfixed developer image on the recording material, covers the electroconductive member, It is formed by insulating the recording material and this conductive member. Since a predetermined voltage is applied to this conductive member, the unfixed developer image is pressed to the recording material side to prevent offset. It is supposed to do. However, when the fixing means is damaged or worn, a leakage current flows through the surface layer damaged portion to a member around the fixing means, and the voltage applied to the conductive member drops. Therefore,
When the voltage is detected by the means for detecting the voltage applied to the conductive member and it is determined that the voltage is lower than a predetermined reference value, it is determined that the fixing means is damaged or worn, and some method is used. Inform the user by. Thus, the user can easily identify the cause of the defective image and know the proper replacement time of the fixing device.

Further, according to the third invention of the present application, the fixing roller is heated to a predetermined temperature by the internal heat source, and the temperature is covered and held by the tape member on the substrate, and the temperature is fixed on the surface of the fixing roller. The temperature is detected by the temperature detecting element arranged so as to be in contact with each other. Therefore, when the fixing operation is performed, the edge portion of the tape member covering the temperature detecting element and the fixing roller repeatedly slide and rub, and a scratch is generated at the abutting portion. However, in the present invention, since the tape member covering the temperature detecting element is bent in a direction away from the fixing roller surface, at least both ends in the axial direction of the fixing roller in the area in contact with the fixing roller surface are bent. The edge portion of does not come into contact with the surface of the fixing roller, and the above-mentioned scratches do not occur.

Further, according to the fourth invention of the present application, since the cleaning member is extended to the non-contact position with the rotating body and attached to the support member, the extended portion is used at the time of replacement of the cleaning device. It is only necessary to clean a portion where the cleaning member is in contact with the rotating body and replace a new cleaning device. Therefore,
It is not necessary to separately provide a member for cleaning the contact point.

Further, according to the fifth invention of the present application, the release layer on the surface is formed of a member having a lower coefficient of thermal expansion or a lower heat shrinkability than the elastic layer below, and wrinkles are generated on the surface when not heated. Since it is attached as described above, it smoothes in the heated state and wipes off the developer adhering to the surface. In addition, the roller shape in the heated state is a straight shape and does not cause wrinkles on the recording material.

[0046]

Embodiments 1 to 15 of the present invention will be described with reference to the drawings.

<Embodiment 1> First, Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 (a) is a view showing a separation claw of the present invention, and a contact portion 7 made of a PTFE resin chip.
02 is press-fitted and adhered to the separation claw body 701 made of PI resin.

FIG. 1B is a diagram showing a state in which the recording material P is separated from the fixing roller 1 when the separating claw shown in FIG. 1A is used when the roller fixing is performed.

In FIG. 1, the fixing roller 1 has a diameter of 30 mm.
The core metal has a release layer 101 of a PFA tube on the surface layer, and this release layer reduces the toner adhesion force and improves the separability. In addition, a region called a front end margin having no toner image is generally provided at the front end portion of the recording material. However, as in this embodiment, a fixing roller having a release layer of fluororesin and having a diameter of 40 mm or less is used. When used,
The leading edge blank area is conveyed from the fixing roller with a gap of 300 to 500 μm by the waist of the recording material.

Therefore, the tip of the separation claw need not necessarily be in contact with the fixing roller. If the gap between the fixing roller and the tip of the separation claw is controlled to 300 μm or less, the recording material can be separated. In this embodiment, this void management is performed by P
The contact portion 702 made of TFE resin is used. PT
Since the releasability of the FE resin is as high as that of PFA, dirt such as toner hardly adheres, and the abrasion resistance is excellent, so that the gap can be managed over a long period of use. Further, as the shape of the contact portion, since it does not contribute to the separating action, it is possible to adopt a point contact type as shown in the figure, and there is no action of scraping the fixing roller surface unlike the conventional separating claw. Adhesion and accumulation of dirt are reduced.

Further, since the PTFE resin is not a high hardness resin such as PAI resin or PI resin and has a low aggression, it is more effective as a countermeasure against roller scratches due to the separating claws than the conventional separating claws.

<Comparative Example> Table 1 will be used to explain the results of comparison between the conventional separating pawl made of PI resin and the separating pawl of this embodiment.

A fixing roller having a diameter of 30 mm with a coating layer of a PFA tube having a thickness of 300 μm was used.
The nail stains and the roller scratches after passing 10,000 sheets were examined. Two separation claws were used, but no separation failure occurred in any of the separation claws, indicating that the separation effect of the separation claw of the present invention is not inferior to the conventional one.

The value in the column of the nail stain is the value obtained by subtracting the initial weight from the weight of the separated nail after the endurance, and represents the weight of the stain attached to the nail. From the table, the separation nail of the present invention collects dirt,
It can be seen that the accumulation action is small, but this fact does not cause toner adhesion on the image due to the separation nail stain that frequently occurs in the conventional separation nails during the entire durability period when the separation nails of the present invention are used. It is also supported by this.

Regarding the roller scratches, it was shown how much the release layer of the fixing roller was scraped due to durability, but obviously the scraping amount was smaller when the separating claw of the present invention was used.

[0056]

[Table 1]

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIG. The same parts as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

FIG. 2 (a) is a view showing the separating claw of the fixing device in the second embodiment of the present invention, and FIG. 2 (b) shows the separating claw as P.
FIG. 6 is a diagram showing a state of separation of the recording material P when the FA tube is used for the fixing roller 1 having the surface coating layer 101.

The separating claw of the present embodiment is characterized in that the width of the contact portion made of PTFE resin in the direction of the rotation axis of the fixing roller is made shorter than the separating claw width as shown in the drawing.
That is, the width of the contact portion in the roller rotation axis direction does not change even if it is subject to wear. As a result, the effect of collecting and accumulating dirt is not increased, and the contact with the surface of the fixing roller is maintained between the fluororesins, which has the effect of reducing the scraped amount of both. As a result, the configuration is excellent in terms of management of the gap between the separation claw tip and the fixing roller.

<Third Embodiment> Next, a third embodiment of the present invention will be described with reference to FIG. The same parts as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted. FIG. 3A is a view showing a separation claw of a fixing device showing Embodiment 3 of the present invention, and FIG.
(B) is a diagram showing a state of separation of the recording material P when the separation claw is used for the fixing roller 1 and the pressure roller 3. The fixing roller 1 and the pressure roller 3 are formed of PFA tubes on the surface coating layers 101 and 301 in order to obtain sufficient releasability.
Are given respectively.

The feature of the separating claw of this embodiment is that the roller 704 made of PTFE resin is used. With such a structure, the contact portion is durable and hardly worn, and the dirt collecting and accumulating action is kept very small. Further, the roller, which is the contact portion, is driven by the rotation of the fixing roller and the pressure roller, and in particular, it can maintain a flexible contact with an elastic roller such as the pressure roller 3, so that it is different from the conventional separating claw. Excellent in comparison.

<Fourth Embodiment> Next, a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 7A is a schematic sectional view of a device of Example 4 of the present invention.

In FIG. 7A, the fixing roller 1 comprises a core metal 102 made of aluminum and a PFA tube coating layer 101 having a thickness of 30 μm provided on the surface thereof.
A voltage of 00V is applied by the power supply 14. The applied voltage has a negative polarity in order to prevent the negative polarity toner from being electrostatically attracted and causing adverse effects such as offset. The recording material P is guided by the guides 10, 16 as shown in the figure.
Although it is conveyed on the sheet and enters the fixing device, since the unfixed toner image on the recording material P is easily disturbed by electrostatic force, these guides are electrically grounded for the purpose of preventing electrification. Reference numeral 15 is a comparator for detecting and comparing the voltage applied to the fixing roller core metal 102, and when the applied voltage is lower than the reference voltage (here, it means that the difference from the ground potential is small), A signal is sent to a control circuit (not shown) that controls the entire image forming apparatus. As the power supply 14, a power supply whose supply voltage changes depending on the load is used. For example, as shown in FIG. 7B, the output of the constant voltage power source 1401 is divided by dividing resistors 1402 and 1403 and supplied.

FIG. 8 is a schematic sectional view in the case of detecting the applied voltage described above by the change of the surface potential of the roller.

In this embodiment, when the applied voltage or surface potential is measured, a waveform as shown in FIG. 9 is obtained when the paper is passed. The vertical axis represents the absolute value of voltage, and the horizontal axis represents time. Time T
The leading edge of the recording material is carried into the fixing nip at 1 and the trailing edge of the recording material is discharged from the nip at time T2. If the surface of the fixing roller is not damaged as shown in FIG. 10A, the PFA resin surface coating layer 101 functions as an insulating layer and maintains the applied voltage V ₁ (= −300V) as shown in FIG. 9A. There is almost no change regardless of whether the recording material is loaded or unloaded. On the other hand, FIG.
As shown in FIG. 9, when the surface coating layer 101 becomes thin, the voltage applied to the core metal of the fixing roller causes a leakage current to flow through the recording material to the guide or the like, resulting in a drop in the power supply voltage.
It becomes lower than V ₁ as shown in (b) and (c). V ₂ is a voltage preset in the comparator, and is determined in consideration of the degree of traces of roller scratches appearing on the image and the life of the fixing device. In this embodiment, it is set to -100V.
The comparator sends a signal to the control circuit when the voltage applied to the core metal of the fixing roller becomes lower than V ₂ . The control circuit can inform the user by sound or display indication that the fixing device has reached the end of its life. In this embodiment, since the recording material to be passed through is used as the current path of the leakage current, damage to the fixing roller can be detected with a simple configuration.

<Fifth Embodiment> Next, a fifth embodiment of the present invention will be described with reference to FIG. The same parts as those of the fourth embodiment are designated by the same reference numerals and the description thereof will be omitted.

FIG. 11 is a schematic sectional view of an apparatus according to the fifth embodiment of the present invention, in which the present invention is applied to a film heating and fixing apparatus. The film heating fixing device can shorten the rising time compared to the roller fixing device, and is excellent as a power-saving fixing device. As a mechanism, the endless film 21 transfers heat of the heater 17 to the recording material from the back surface while moving at a constant speed with the recording material to fix the toner image. Since the heat capacity of the film 21 is much smaller than that of the roller. Further, it becomes possible to instantly bring the fixing portion to a predetermined temperature. Reference numeral 3 is a pressure roller for forming a nip at the fixing portion, 22 is a drive roller for driving the film 21, and 23 is a tension roller for applying tension to the film 21. 20 for film 21
A material having a thickness of about 100 μm is suitable in terms of thermal conductivity, strength and the like. The present embodiment is an example in which the present invention is used to monitor the state of the film 21.

The film 21 may be damaged due to rough handling or the like when the jam is restored, and this may cause not only an image defect but also a fatal defect such as inability to drive the film. Therefore, in this embodiment, in order to detect the damage of the film, the heater 17 is provided with the electrode 24 and a voltage is applied thereto, and the voltage is detected by the means described in the fourth embodiment. FIG. 12 is a top view of the heater 17 as seen from the heating element side, and 19 is a heating element and 24 is a detection electrode. As described in the fourth embodiment, when the voltage detected by the comparator 15 becomes lower than the reference voltage, a signal is sent to a control circuit (not shown) that controls the entire image forming apparatus, and the fixing device It is possible to inform the user that there is an abnormality.

<Sixth Embodiment> Next, a sixth embodiment of the present invention will be described with reference to FIG. FIG. 13 is a schematic sectional view of a device according to the sixth embodiment of the present invention. In FIG. 13, the fixing roller 1 has a PF having a thickness of 30 μm on the surface of an aluminum cored bar 102.
A tube coating layer 101 is provided, and the pressure roller has an elastic layer 303 formed of conductive silicone rubber,
Fixing roller core metal 102 and pressure roller conductive elastic layer 303
And a potential difference of 300 V is applied by the power source 14. Reference numeral 15 denotes a comparator that detects and compares the potential difference between the fixing roller core metal 102 and the pressure roller conductive elastic layer 303 and the reference potential difference, and when the detected potential difference is lower than the reference potential difference, the entire image forming apparatus is shown. A signal to a control circuit (not shown) that controls the. The feature of this embodiment is that the damage of the fixing roller surface coating layer is detected when the paper is not passed. This is possible because the potential difference applied between both roller cores does not change via the recording material when the coating layer is broken, but the roller itself forms a short circuit by making the pressure roller conductive. Become. With this configuration, it is possible to confirm a defect at the time of starting the device or at the time of standby, and it is possible to detect the defect more quickly.

<Seventh Embodiment> Next, a seventh embodiment of the present invention will be described with reference to FIG. FIG. 14 shows a view in which an NTC 202 is pressed against a PFA-coated aluminum fixing roller 201 by a leaf spring (not shown) at a pressure of about 100 g. The NTC 202 has a temperature detecting sensor 20 at the center of the silicone sponge 204 on the polyimide substrate 203.
5 is provided and is covered with a polyimide tape 206. The tape is tightly wound around the roller in the direction in which the roller rotates (from the front to the back in the figure). Then, in order to prevent the edge portion of the polyimide tape 206 from coming into contact with the fixing roller 201, the width of the tape is made larger than the sponge and both ends thereof are bent toward the substrate side as shown in the figure, and the substrate is made of needle-shaped stainless steel 207. Fixed to. Reference numeral 208 in the drawing indicates a lead wire of the temperature sensor.

A fixing roller 201 was brought into pressure contact with a pressure roller so that the jig could be rotated to perform idling durability by rotating for 25 seconds and then resting for 5 seconds as one cycle. At this time, a halogen heater was arranged inside the fixing roller and the temperature of the NTC part was adjusted to 180 ° C.

When the surface of the fixing roller 201 was checked at the time when the above-mentioned idling durability was repeated 100,000 cycles, a portion corresponding to the temperature detection sensor 205 was found in FIG.
As shown in FIG. 4, roller scratches 205a were confirmed.
No roller scratches due to the edges of the tape corresponding to Nos. 206a and 206b were observed.

As the durability was further advanced, roller scratches due to the edge of the tape did not occur even after 300,000 cycles.

It is needless to say that when the fixing roller of the image forming apparatus is incorporated in the fixing device and the image is confirmed, the image stain does not occur at the portion corresponding to the edge of the tape.

<Embodiment 8> Next, Embodiment 8 of the present invention will be described with reference to FIG. In addition, the same parts as those of the seventh embodiment are designated by the same reference numerals and the description thereof will be omitted.

FIG. 15 shows a state where the NTC 202 is pressed against the fixing roller 201 with a pressure of about 100 g as in FIG. Similar to FIG. 14, the polyimide tape 206 wound around the NTC 202 is tightly wound around the fixing roller in the rotating direction, but a phosphor bronze sheet metal 209 is provided between the temperature detection sensor 205 on the silicone sponge 204 and the polyimide tape. It is sandwiched.

In order to prevent the edge of the tape from coming into contact with the fixing roller, the tape was bent and adhered to the sponge as shown by 206 'in FIG.

When the idling durability was carried out in the same manner as in Example 7, the temperature sensor 20 was used even at the time of 200,000 cycles.
Roller scratches did not occur at all in the portion 5 and the edge portion of the tape.

It was also feared that the square edge portion of the bent tape might cause roller scratches, but this portion was carefully observed and found to be out of contact with the fixing roller.

<Ninth Embodiment> Next, a ninth embodiment of the present invention will be described with reference to FIG. In addition, the same parts as those of the seventh embodiment are designated by the same reference numerals and the description thereof will be omitted.

From the examination results of Example 8, the fact that the squares of the polyimide tape do not contact the fixing roller was used, and in this example, as shown in FIG. 16, the silicone sponge 2 was used.
In 04, the polyimide tape 206 was wound tightly around the longitudinal direction, not around the rotation direction of the fixing roller.

At this time, if the width 204L of the sponge is made too small with respect to the outer diameter of the fixing roller 201, the upper and lower edge portions of the tape on the side in contact with the fixing roller hit, so that the sponge width can be adjusted according to the outer diameter. Need to be selected. The width 206L of the tape is 0.5 mm or more, preferably 1 to 4 mm larger than the width of the sponge. In this embodiment, the fixing roller diameter is 28 mm, the sponge width is 204 L = 8 mm, and the tape width is 206 L = 11 mm.
And

In the same manner as in Example 7, the idling durability was set to 30.
After 10,000 cycles, there was no problem at all except the roller scratches on the sliding portion of the sensor 205.

In this embodiment, the NTC tape abutted on the fixing roller has been described, but it goes without saying that the NTC tape is not limited to this. For example,
It can also be applied when monitoring the temperature of the surface of the photosensitive drum by the above-mentioned NTC.

The type of tape is not limited to polyimide, and it goes without saying that a fluororesin tape such as PFA or PTFE, or a tape obtained by coating the fluororesin on a substrate such as polyimide can be used.

<Embodiment 10> Next, Embodiment 10 of the present invention.
Will be described with reference to FIG. FIG. 18 is a diagram for explaining the tenth embodiment of the present invention. In addition, the same parts as those of the conventional apparatus shown in FIG.

In this embodiment, in the fixing device as shown in FIG. 21, as shown in FIG. 18, the cleaning pad 407a is extended to the end of the cleaning device 407 to have an L-shaped cleaning pad 407a. Therefore, as in the conventional example, after the cleaning of the cleaning device 407 by the end pads, it is possible to save the trouble of removing the end pads and mounting them on the fixing device, and mounting them on the fixing device as they are after cleaning.

Further, since the mechanism for removing the end pads can be omitted, there are advantages that the cost is reduced and the productivity is improved.

<Embodiment 11> Next, an embodiment 11 of the present invention.
Will be described with reference to FIG. The same parts as those of the tenth embodiment are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, as shown in FIG. 19, the cleaning pads 407a are extended to both ends to form a U shape,
Since the cleaning device attaching / detaching portion can be cleaned not only at one end but also at two positions at both ends, the cleaning can be performed more reliably.

Moreover, since the cleaning device can be made symmetrical, it is possible to prevent erroneous mounting on the left and right.

<Embodiment 12> Next, Embodiment 12 of the present invention.
Will be described with reference to FIG. The same parts as those of the tenth embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the present embodiment, as shown in FIG. 20, the cleaning pad is extended not only to both ends but also to the opposite surface, and one round of the cleaning device is constituted by the cleaning pad. Not only at the location, but when the cleaning pad is soiled by the offset toner, using the opposite surface has the advantage of doubling the life of the cleaning device.

<Embodiment 13> Next, Embodiment 13 of the present invention.
Will be described with reference to FIG. FIG. 23 is a vertical sectional view of a fixing device using a pressure roller 502 ′ according to a thirteenth embodiment of the present invention. The same parts as those of the conventional example shown in FIG. 27 are designated by the same reference numerals and the description thereof will be omitted.

The pressure roller 502 'has a core metal 521 and an adhesive 523 on the inner surface of which a fluororesin tube 524 having a surface layer is disposed in a mold (not shown), and silicone rubber is injected in a liquid state between the two. After that, it is molded by heating and pressurizing.
By adjusting the injection amount of the liquid silicone rubber at the time of molding, uneven wrinkles are generated on the surface of the pressure roller 502 'as shown in FIG. Make sure to obtain a smooth surface as in B). This is the expansion coefficient β of the fluororesin tube 524.
Expansion coefficient β2 of the elastic layer 522, 1 of which is made of silicone rubber
Utilizing the fact that it is smaller, wrinkles do not occur during heating,
The amount of the liquid silicone rubber is adjusted so that wrinkles are generated during cooling. By the way, fluororesin tube 5
A tube made of PTFE or PFA (thickness 30 to 100 μm) can be used as 24, and the linear expansion coefficient β1 of the fluororesin tube 524 is 1 × 10 ⁻⁴ to 2 ×.
It is 10 ⁻⁴ cm / cm / ° C., which is smaller than 3 × 10 ^{−4 to} 5 × 10 ⁻⁴ cm / cm / ° C., which is the linear expansion coefficient β2 of the silicone rubber that can be used as the material of the elastic layer 522.

The pressure roller 50 molded in this way
With 2 ', if a fusing device is used,
As shown in FIG. 23 (B), the surface is smooth and good fixing properties are obtained. On the other hand, when the fixing device is not used and the power is turned off, the pressure roller 502 ′ is accustomed to room temperature, and the surface is folded. Causes wrinkles. The offset toner adhered to the fixing roller 501 in a trace amount tends to accumulate on the pressure roller 502 'due to the action of the electric field in the nip N and grow from a point-like adhered state to a linear or planar state. Since the surface of the pressure roller 502 'repeatedly changes in smoothness-folding in response to cooling, the toner adhered and grown on the surface of the pressure roller 502' is driven by the fixing device and the pressure roller 502 'is cooled. As the pressure roller 502 ′ rotates, the pressure roller 502 ′ is pressurized and shredded in the nip N so as to be separated from the surface. Therefore, when the pressure roller 502 'of this embodiment is used, a small amount of toner may be attached to the paper sheet 505, but the toner is not attached in an unpleasantly large amount.

As the wrinkles on the surface of the pressure roller 502 ', the wrinkle interval is 1 to 50 mm and the wrinkle depth is 0.5 to.
The above effect was obtained when the wrinkle length was 2.0 mm and the wrinkle length was 50 to 200 mm.

Example 14 Next, Example 14 of the present invention.
Will be described with reference to FIGS. 24 and 25. The same parts as those of the thirteenth embodiment are designated by the same reference numerals and the description thereof will be omitted.

24 and 25 are a longitudinal sectional view and a lateral sectional view of a pressure roller 502 "according to a fourteenth embodiment of the present invention. In FIG. 24, 522 'is a sponge layer made of foamed silicone rubber. The layer 522 ′ is formed by bonding an extruded sponge tube onto the core metal 521,
The surface is cut and finished to a predetermined external dimension. Then, the adhesive 523 is applied on the sponge layer 522 to cover the heat-shrinkable fluororesin tube 524, and heated to obtain the pressure roller 502 ″.

[0100] Here, the sponge layer 522 'after the surface cutting
Fluorine resin tube 524 before heat shrink
If the inner diameter dimension of B is B, the value of conventional B is almost the same as that of A, and the inner diameter B ′ of the fluororesin tube 24 after heat shrinking in a natural state is a value smaller than A. As shown in FIG. 29 (A), the surface is smooth in the cooled state, but at the time of heating, there is a problem that the cross-sectional shape is crowned as shown in FIG. 29 (B).

In this embodiment, the inner diameter B of the fluororesin tube 524 before heat shrinkage is the inner diameter B ′ of the fluororesin tube 524 after heat shrinkage in the natural state and the outer diameter A of the sponge layer 522 ′ after surface cutting. It is selected so as to be almost the same as, and as shown in FIG. 25 (A), folding wrinkles are formed on the surface during cooling. In this way, when the fixing device is driven and used for heating, as shown in FIG.
As shown in (B), the surface is smooth, and the cross-sectional shape is a straight shape according to the shape of the sponge layer 522 ′ without being restricted by the fluororesin tube 523, and wrinkles occur on the paper sheet 505. Good fixing property can be secured without causing

<Embodiment 15> Next, Embodiment 15 of the present invention.
Will be described with reference to FIG. The same parts as those of the thirteenth embodiment are designated by the same reference numerals and the description thereof will be omitted.

FIG. 26 shows a main part of a longitudinal sectional view of the fixing device using the fixing roller 501 ′ and the pressure roller 502 ′ according to the fifteenth embodiment of the present invention when the fixing device is cooled. In FIG. 26, 5
11 is a core metal, 512 is an elastic layer, 513 is an adhesive layer, 514
Is a fluororesin layer. In the thirteenth and fourteenth embodiments, the present invention is applied to the pressure rollers 502 ′ and 502 ″, but in the present embodiment, the present invention is applied to the fixing roller 501 ′. The surface of the fixing roller 501 ′ is also applied. In addition, since the uneven wrinkles are formed during cooling, the effect of breaking the toner adhering to the surface of the pressure roller 502 ′ at the time of rising after driving the fixing device is doubled.
Is an elastic roller having an elastic layer 512, the paper sheet 505 does not curl in the nip N.
Since the cross-sectional shape during heating is not affected by the fluororesin layer 514 and the natural shape of the elastic layer 512 can be maintained, wrinkles do not occur on the paper sheet 505 and the fixed image is not disturbed. .

[0104]

As described above, according to the first invention of the present application, the rotating member for fixing the unfixed developer image on the recording material and the recording material separating member arranged so as to be in pressure contact with the rotating member. In the fixing device having the fixing member, at least the contact portion of the separating member with the rotating member is formed of a molded product of fluororesin, so that the releasability of the surface of the rotating member is secured for a long period of time, and the offset toner to the separating member It is possible to prevent the deterioration of the separation performance by preventing the adhesion of dirt such as the like. Furthermore, by separating the contact portion of the separation member with the rotating member from the recording material separation portion, sharp and high-hardness performance is required. It is possible to separate the tip separation part from the rotating body, and to manage the position of the separation part with a fluororesin for the contact part that requires abrasion resistance and low aggression. Secured and durable It can provide a fixing device.

According to the second invention of the present application, in the heat and pressure type fixing device, the surface layer of the fixing means on the side of the recording material which comes into contact with the unfixed developer image is covered with the conductive member to form the recording material. And a conductive member is formed in an insulating manner, a predetermined voltage is supplied to the conductive member, and a detection unit for detecting the voltage or the potential difference between the fixing units is provided, thereby providing a recording material in the fixing device. It is possible to detect damage or deterioration of the contacting surface layer, and to easily identify the cause of a defective image. Furthermore, by outputting a message to replace the fixing device and notifying the user that the fixing device has reached the end of its life, it becomes possible to quickly replace the parts when the fixing device reaches the substantial end of life, and to effectively use the device. It is possible and can always ensure good image quality.

Further, according to the third invention of the present application, in the tape member of the temperature detecting element to be brought into contact with the fixing roller, at least both ends in the axial direction of the fixing roller in the area to be brought into contact with the fixing roller are separated from the surface of the fixing roller. Since it is bent in the direction, it is possible to prevent roller scratches and scrapes, eliminate image stains and roller stains due to this, and achieve a long service life of the fixing device.

According to the fourth aspect of the present invention, the cleaning member of the cleaning device is extended to the non-contact position with the fixing rotator, thereby saving the trouble of removing the end pad after cleaning when replacing the cleaning device. In addition to providing an easy-to-use cleaning device, it is possible to reduce costs and improve productivity.

Further, according to the fifth invention of the present application, the offset toner adheres to the release layer, which is the surface layer formed on the elastic layer of the roller, by causing wrinkles during cooling which is adapted to room temperature. To prevent heavy dirt,
Further, the cross-sectional shape of the roller does not deform into a crown shape during heating and wrinkles do not occur on the recording material.

[Brief description of drawings]

1A is a perspective view of a separation claw according to a first embodiment of the present invention, and FIG. 1B is a vertical cross-sectional view showing a state of recording material separation according to a first embodiment of the present invention.

FIG. 2A is a perspective view of a separation claw according to the second embodiment of the present invention, and FIG. 2B is a vertical cross-sectional view showing a state of recording material separation according to the second embodiment of the present invention.

3A is a perspective view of a separation claw according to a third embodiment of the present invention, and FIG. 3B is a vertical cross-sectional view showing a state of recording material separation according to the third embodiment of the present invention.

FIG. 4 is a vertical cross-sectional view of a conventional fixing device.

FIG. 5A is a perspective view of a separation claw in a conventional example,
(B) is a longitudinal sectional view showing a state of recording material separation in a conventional example.

FIG. 6A is a perspective view of a conventional non-contact separation guide,
(B) is sectional drawing which shows the conventional non-contact separation guide.

FIG. 7 is a diagram showing a schematic configuration of an apparatus of Example 4 of the present invention.

FIG. 8 is a diagram showing a schematic configuration in the case where the detection of the applied voltage is detected by the change of the surface potential of the roller in Example 4 of the present invention.

FIG. 9 is a diagram showing a voltage drop applied to a fixing roller in the apparatus of FIG.

FIG. 10 is a diagram for explaining the principle of the present invention in a fourth embodiment.

FIG. 11 is a diagram showing a schematic configuration of an apparatus of Example 5 of the present invention.

12 is a diagram showing a schematic configuration of a film heat fixing heater used in the apparatus shown in FIG.

FIG. 13 is a diagram showing a schematic configuration of an Example 6 apparatus of the present invention.

FIG. 14 is a diagram showing a schematic configuration of an apparatus of Example 7 of the present invention.

FIG. 15 is a diagram showing a schematic configuration of an apparatus according to an eighth embodiment of the present invention.

FIG. 16 is a diagram showing a schematic configuration of an apparatus of Example 9 of the present invention.

FIG. 17 is a diagram showing a schematic configuration of a conventional device.

FIG. 18 is a diagram showing a schematic configuration of an apparatus according to Example 10 of the present invention.

FIG. 19 is a diagram showing a schematic configuration of an apparatus according to Example 11 of the present invention.

FIG. 20 is a diagram showing a schematic configuration of an apparatus of Example 12 of the present invention.

FIG. 21 is a diagram showing a schematic configuration of a conventional device.

FIG. 22 is a diagram showing a schematic configuration of a cleaning device used in the device of FIG. 22.

FIG. 23 is a diagram showing a schematic configuration of a pressure roller in Example 13 of the present invention.

FIG. 24 is a diagram showing a schematic configuration of a pressure roller in Example 14 of the present invention.

FIG. 25 is a diagram showing a shape of the pressure roller during cooling and during heating according to Example 14 of the present invention.

FIG. 26 is a diagram showing a schematic configuration of a fixing roller and a pressure roller in Example 15 of the present invention.

FIG. 27 is a diagram showing a schematic configuration of a conventional fixing device.

28 is a diagram showing a schematic configuration of a pressure roller in the apparatus shown in FIG. 27.

29 is a diagram showing the shape of the pressure roller of FIG. 28 during cooling and heating.

[Explanation of symbols]

 1 Fixing Roller (Rotating Member, Fixing Means) 7 Separation Claw (Separating Member) 702 Contact Area P Recording Material 14 Power Supply (Means for Applying Voltage) 15 Comparator (Means for Detecting Voltage) 21 Film (Fixing Means) 101 PFA Tube Coating layer (surface coating layer) 201 Fixing roller 202 NTC (temperature detecting element) 203 Polyimide substrate (substrate) 206 Polyimide tape (tape member) 405 Fixing roller (rotating body) 407 Cleaning device 407a Cleaning pad (cleaning member) 407b Heat resistance Plastic (supporting member) 501 'Fixing roller (fixing roller) 502', 502 "Pressure roller (fixing roller) 512, 522 Elastic layer 514 Fluororesin layer (release layer) 522 'Sponge layer (elastic layer) 524 Fluororesin tube (release layer)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical display location G01M 19/00 Z G03G 15/00 103 21/00 111 (72) Inventor Kazuro Ono Ota-ku, Tokyo Shimomaruko 3-30-2 Canon Inc.

Claims (9)

[Claims] 1. A rotating member for nip-conveying a recording material carrying an unfixed developer image to melt and fix the unfixed developer image on the recording material, and recording by a recording material nipping portion of the rotating member. In a fixing device provided in front of a material conveying direction and provided with a separating member for separating the recording material from the rotating member, the separating member is arranged so as to come into pressure contact with the rotating member with a predetermined pressing force. The fixing device is characterized in that at least a contact portion with the rotating member is formed of a fluororesin. 2. The rotating member has a fluororesin layer or a fluororesin coating layer as the outermost layer on the side contacting the separating member, or carbon, metal oxide, ceramic, or another fluororesin dispersed in the fluororesin. The fixing device according to claim 1, further comprising a release layer formed of the resin. 3. The fixing device according to claim 1, wherein the contact portion of the separating member is provided at a position different from the recording material separating portion. 4. The fixing device according to claim 1, wherein the rotating member has no other contact member in the same circumferential direction as the position where the separating member contacts. 5. A recording material having surface layers which are arranged in pressure contact with each other and nip and convey a recording material carrying an unfixed developer image, and the unfixed developer image is melted and fixed onto the recording material. In a fixing device provided with a fixing means, a surface layer of the fixing means, which is in contact with the unfixed developer image on the recording material, covers a conductive member to insulate the recording material and the conductive member. And a means for supplying a voltage to the conductive member, a means for detecting the voltage, and the surface layer being worn or damaged when the voltage detected by the means is lower than a predetermined reference value. And a control unit set so as to determine that the fixing device has performed. 6. The fixing device according to claim 5, wherein the means for detecting the voltage is set so as to detect a potential difference between the fixing means. 7. A fixing device comprising: a fixing roller containing a heat source; and a temperature detecting element arranged so as to contact the surface of the fixing roller and held on a substrate covered with a tape member. The fixing device is characterized in that at least an end of the tape member in the axial direction of the fixing roller in a region in contact with the surface of the fixing roller is separated from the surface of the fixing roller. 8. A cleaning member disposed so as to abut at least one of a pair of rotating bodies that nip and convey a recording material carrying an unfixed developer image, and the cleaning member. A cleaning device including a support member, wherein the cleaning member is attached to the support member by being extended to a non-contact position with the rotating body. 9. A fixing roller comprising a release layer on the surface and an elastic layer below the release layer, which is directly or indirectly heated by a heat source, wherein the release layer on the surface is elastic. A fixing roller, which is formed of a member having a coefficient of thermal expansion lower than that of a layer or a coefficient of thermal contraction lower than that of the layer, and is mounted so as to cause wrinkles on the surface when not heated.