JPH10149042A - Heating device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heating device having a rotor which contacts in rotation with a material to be heated, in which exhaust of the actual life associated with the wear of the heating rotor can be sensed accurately irrespective of variation in the sustainable number of sheets due to the sheet supply mode of the material to be heated or environmental change. SOLUTION: A heating device includes rotor life sensing means 27 and 28 to sense the exhausting life of a rotor through monitoring of the thickness of a heating rotor 24 for material to be heated and an alarm means 29 to be actuated upon the lifetime sensing information. The rotor life sensing means monitor difference in the optical properties between the outer extremity layer and its next layer or underlayer thereafter, for example difference in the reflecting density, in case the rotor is of laminate structure, and the exhausting lifetime of the rotor is judged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating device having a rotating body for rotating a material to be heated by rotating the material to be heated.
The present invention relates to an image forming apparatus including the heating device as an image heating device for heating and fixing an unfixed image on a recording material.

[0002]

2. Description of the Related Art For example, in an image forming apparatus such as a printer, a copier, a facsimile, etc., a recording material such as a transfer material sheet, printing paper, photosensitive paper (electrofax sheet), electrostatic recording paper, etc. A heat fixing device for thermally fixing an unfixed developer image (unfixed toner image) formed and supported by a transfer (indirect) method or a direct method by an appropriate image forming process means such as recording or magnetic recording. As an image heating apparatus, a contact roller heating apparatus such as a heat roller method, a film heating method, and an electromagnetic (magnetic) induction heating method is widely used.

A heating device of the heating roller type is a heating roller which is heated by a heat source such as a halogen lamp and is adjusted to a predetermined temperature, and a rotating roller pair of a pressing roller pressed against the heating roller (fixing roller). The recording medium as a heated material is introduced into a press-contact nip portion (fixing nip portion) of the two rollers and is nipped and conveyed, so that the unfixed developer image on the recording material surface is heated by the heat roller. Is heated and fixed.

A heating device of a film heating type is disclosed in
JP-A-3-313182, JP-A-1-263679, JP-A-2-15778, JP-A-4-44075, JP-A-4-44075-44083, JP-A-4-20
It has been proposed in, for example, Japanese Patent No. 4980-204984 and has been put to practical use.

In this apparatus, a material to be heated is brought into close contact with a heating body fixed and supported by a supporting member via a heat-resistant thin-walled film material (fixing film), and the film material is slidably moved to the heating body to heat the material. This is a system configuration in which heat of a body is given to a material to be heated via a film material. As a heating element, a ceramic substrate made of, for example, alumina (Al ₂ O ₃ ) or aluminum nitride (AlN) having characteristics such as heat resistance, insulation, and good thermal conductivity is used. A so-called ceramic heater having a resistive layer provided on the surface of the substrate and generating heat by energization as a basic structure can be used, and a thin film having a low heat capacity can be used as a film material. The heat transfer efficiency is higher than that of the heating device, the start-up of the device is quicker, the wait time can be reduced (quick start property: operated on demand), and power consumption can be reduced. Generally, the above-mentioned film material is formed into a cylindrical or endless belt shape, and the film material is rotated by sliding the inner surface of the film material in close contact with a heating body.

As a heating device of the electromagnetic induction heating type, Japanese Patent Publication No. 5-9027 proposes that an eddy current is generated in a rotary fixing roller by magnetic flux and heat is generated by Joule heat. By utilizing the generation of the eddy current in this way, the heat generation position can be made closer to the toner image of the recording material as the material to be heated, and the energy consumption can be increased more efficiently than the heating device of the heat roller type. There are advantages.

As a heating device of the electromagnetic induction heating type,
Rotating a cylindrical or endless belt-shaped film material (fixing film) including a layer that generates electromagnetic induction by the action of a magnetic field, and bringing a material to be heated into contact with the outer surface side of the film material,
The device may be configured to heat the material to be heated by the heat generated by the electromagnetic induction heating layer of the film material, or a member serving as a heating element that generates electromagnetic induction heat by the action of a magnetic field may be fixedly supported on a support member. The inner surface of a heat-resistant, thin-walled cylindrical or endless belt-like film material (fixing film) that does not include an induction heating layer is rotated by closely sliding it, and the heat generated by the electromagnetic induction heating member is heated via the film material. It can also be of a device configuration to be provided to the user.

[0008]

Here, in the heating device of the present invention, the rotating body that rotates and contacts the material to be heated and heats the material to be heated is the rotating heat roller in the heating device of the above-described heat roller type. (Fixing roller), cylindrical or endless belt-shaped rotating film material (fixing film) in a film heating type heating device, electromagnetic induction heating rotary fixing roller in an electromagnetic heating type heating device, or electromagnetic induction by the action of a magnetic field A cylindrical or endless belt-shaped rotating film material (fixing film) including a layer that generates heat, or a heat-resistant thin-walled cylindrical or endless belt-shaped rotating film material (fixing film) that does not include an electromagnetic induction heating layer. .

In general, in a heating apparatus having a rotating body that rotates and contacts a material to be heated to heat the material to be heated, the rotating body to be heated is repeatedly used for heating the material to be heated. That is, as the number of endurance increases, the surface layer on the outer surface that is in contact with the material to be heated is generally or partially shaved from the release layer, and when a certain amount or more is shaved,
In the image heating and fixing apparatus, a fixing failure occurs, and when the heated rotary member is a film material, the film material is damaged or the like, and the life is extended. It is necessary to take measures such as replacement of the heated rotary member that has reached the end of its life.

Conventionally, the number of durable sheets and the use time corresponding to the life of the heated material heating rotary body are set in advance by experiments and the like. The service life and other measures such as replacement are taken.

However, the life of the heated rotary member is actually more closely related to the total number of rotations than to the number of endurance sheets and the time of use. This is because, in the image forming apparatus, the number of rotations of the heating member heating rotary member when printing one sheet differs between continuous printing and intermittent printing.

Therefore, for example, when it is assumed that the heated material heating rotator has reached the end of its life due to reaching a preset number of durable sheets, as described above, the heated material heating rotator depends on the use conditions of the apparatus. Since the total number of rotations as the actual life of the heating material is different, even if the number of durable sheets of the heated material heating rotating body reaches the predetermined number of durable sheets as the predetermined life, the heated material heating rotating body actually still reaches the life. There may be a case where the heating member heating rotary body is still usable, in which case it may be replaced as soon as possible.

Conversely, even when the number of durable sheets of the heated rotary member has not reached the durable number as a predetermined life, the heated rotary member may have already reached the end of its life. In this case (at the time of intermittent printing), in this case, the replacement of the heated rotating body which has reached the end of its life has been missed and continued to be used, resulting in poor fixing and film material as the heated rotating body. This may cause troubles such as breakage.

[0014] The same problem as described above can also occur when the heated material heating rotary body reaches the end of its life due to reaching the preset use time.

That is, the number of durable sheets and the service time as the life of the heated material heating rotary body are set in advance through experiments and the like. The method of taking measures such as replacement as a problem is likely to cause a difference between the actual life of the heated material heating rotary body and the accuracy of the life detection of the heated material heated rotary body.

Therefore, the present invention relates to a heating apparatus having a rotating body which rotates in contact with a material to be heated and heats the material to be heated. It is an object of the present invention to accurately detect regardless of a difference in the number of durable sheets due to a paper mode or an environmental change.

[0017]

According to the present invention, there is provided a heating apparatus and an image forming apparatus having the following constitutions.

(1) In a heating device having a rotating body for rotating and heating the material to be heated by rotatingly contacting the heated material, a rotating body life detecting means for monitoring the thickness of the rotating body and detecting the life of the rotating body. A heating device comprising:

(2) In a heating device having a rotating body for rotating and heating the material to be heated by rotatingly contacting the heated material, a rotating body life detecting means for monitoring the thickness of the rotating body and detecting the life of the rotating body. And a warning device that operates based on life detection information of the device.

(3) In the heating device according to the above (1) or (2), the rotating body life detecting means includes an outermost layer when the rotating body is formed by laminating a plurality of layers. A heating device characterized by monitoring the difference in optical properties between the next lower layer below the outermost layer and the subsequent lower layer to detect the life of the rotating body.

(4) The heating device according to (3), wherein the difference in optical properties of the rotator-constituting layers is a difference in reflection density.

(5) The heating device according to any one of (1) to (4), further comprising a member for rubbing a part of the rotating body, and a film of the rotating body part rubbed by the member. A heating device characterized by monitoring the thickness.

(6) In the heating device according to the above (5), an intermediate layer for life detection is provided below the outermost layer below the outermost layer of the rotating body portion rubbed by the rubbing member. And a heating device.

(7) In a heating device having a rotating body for rotating and heating the material to be heated by rotatingly contacting the heated material, the rotating body is provided with a rotating body life detecting layer different in color from at least another layer. A heating device.

(8) In the heating device according to any one of (1) to (7), the rotating body includes a layer that generates electromagnetic induction by the action of a magnetic field, and heats the material to be heated by the heat generated by the layer. A heating device, characterized in that:

(9) The heating device according to any one of (1) to (8), further comprising a pressing member forming a nip portion with the rotating body, and introducing a material to be heated into the nip portion and holding the nip portion. A heating device characterized by being transported and heated.

(10) In the heating device according to any one of (1) to (9), the material to be heated is a recording material carrying an image, and the device heats the image carried on the recording material. A heating device, which is an image heating device for processing.

(11) The heating device according to (10), wherein the image heating process is a heating and fixing process for an image on a recording material.

(12) An image forming apparatus comprising the heating device according to any one of (1) to (11) as an image heating device for heating and fixing an unfixed image on a recording material.

<Operation> That is, the state of the film thickness (scraped) of the heated rotary member to be heated, which is scraped due to durability and becomes a service life by being scraped by a certain amount or more, is directly monitored (monitored). Detects that the film has reached the film thickness state corresponding to the end of the life of the heated material heating rotator, allowing accurate heating of the heated material regardless of the difference in the number of durable sheets due to the material passing mode or environmental changes. It is possible to detect the actual life of the rotating body.

Also, a member is provided for rubbing a part of the heated material heating rotary body, and the film thickness of the heated material heated rotary body rubbed by the rubbing member is monitored to assuredly. It is possible to detect the actual life of the heated rotary member.

The detection that the film thickness of the heated material heating rotator has reached the film thickness state corresponding to the end of the life is detected, for example, when the heated material heating rotator is formed by laminating a plurality of layers. By monitoring a difference in optical properties between the outermost layer and a next layer below the outermost layer or a layer below the outermost layer, for example, a difference in reflection density, it can be easily and accurately detected.

In the above case, even when the reflectance of the outermost layer of the heated rotary member to be heated and the lower layer thereafter are close to each other and it is difficult to detect the difference in reflection density with the sensor, the intermediate layer for detecting the life can be provided. In addition, it is possible to easily and accurately detect the actual life of the heated rotary member.

Further, a rotating body life detecting layer having a different color from at least another layer is provided on the heated material heating rotary body. For example, when the surface layer of the heated material heating rotating body is scraped off due to durability and is cut by a certain amount or more. By giving a specific color or a marking indicating a life warning to the appearing intermediate layer, a user or a serviceman can visually recognize the appearance of the intermediate layer and recognize that the heated material heating rotary body has reached the end of its life. Therefore, in the case of this configuration, a sensor for measuring the reflection density for monitoring the film thickness of the heated rotary member to be heated can be omitted, and the configuration can be simplified.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION

<Embodiment 1> (FIGS. 1 to 6) (1) Example of Image Forming Apparatus FIG. 1 is a schematic configuration diagram of an example of an image forming apparatus. The image forming apparatus of this embodiment is a laser beam printer using a transfer type electrophotographic process.

Reference numeral 1 denotes a rotating drum type electrophotographic photosensitive member (hereinafter, referred to as a photosensitive drum) as a first image carrier.

The photosensitive drum 1 is driven to rotate in a clockwise direction indicated by an arrow at a predetermined peripheral speed (process speed).
It is uniformly charged to a predetermined dark potential V _D of the negative by a primary charger 2 at its rotation process.

Reference numeral 3 denotes a laser beam scanner, which is a laser beam L modulated in accordance with a time-series electric digital image signal of target image information input from a host device such as an image reading device, word processor, or computer (not shown). Is output, and the uniformly charged surface of the rotating photosensitive drum 1 is scanned and exposed.

By this laser beam scanning exposure, the exposed portion of the uniformly charged surface of the rotary photosensitive drum 1 has a small absolute value of potential and becomes a bright potential _VL , and the surface of the rotary photosensitive drum 1 corresponds to the target image information. An electrostatic latent image is formed.

Next, the latent image is reversal-developed (toner is adhered to the laser exposure light potential _VL portion on the surface of the photosensitive drum) with the negatively charged powder toner by the developing device 4 to be visualized as a toner image.

The developing device 4 is a developing sleeve 4 which is driven to rotate.
The developing sleeve 4a is coated with a thin layer of negatively charged toner and is opposed to the surface of the photosensitive drum 1. The developing sleeve 4a has an absolute value of the dark potential V of the latent image on the photosensitive drum 1 surface. _{Since the} developing bias voltage _VDC smaller than _{D and} larger than the bright potential _VL is applied, the toner on the developing sleeve 4a is transferred only to the portion of the latent image on the photosensitive drum 1 having the bright potential _VL. The latent image is developed (reversal development).

On the other hand, a recording material 15 as a second image carrier loaded and set on a paper feed tray 14 is fed out one by one by the driving of a paper feed roller 13, and is conveyed by a transport guide 12a and a resist. A transfer roller 5 serving as a transfer member to which a transfer bias is applied in contact with the photosensitive drum 1 via a pair of rollers 10 and 11 and transfer guides 8 and 9.
The photosensitive drum 1 to the transfer nip m, which is the pressure contact nip
Are fed at an appropriate timing synchronized with the rotation of the photosensitive drum 1, and the toner image on the photosensitive drum 1 surface side is sequentially transferred to the surface of the fed recording material 15. The transfer roller 5 as a transfer member preferably has a resistance of about 10 ⁸ to 10 ⁹ Ωcm.

The recording material 15 that has passed through the transfer nip m is separated from the surface of the rotating photosensitive drum 1 and introduced into the fixing device 7 as an image heating device by the conveyance guide 12b, and undergoes a fixing process of the transferred toner image. It is output to the paper discharge tray 16 as a formed product (print).

After the recording material is separated, the surface of the rotating photosensitive drum 1 is cleaned by the cleaning device 6 to remove the remaining photosensitive drum surface residue such as toner remaining after transfer, and is repeatedly used for image formation.

(2) Fixing Device 7 FIG. 2 is a schematic cross-sectional view of the fixing device 7 of this embodiment. The fixing device 7 of this example is a heating device of an electromagnetic induction heating system and a pressure roller drive system using a cylindrical film material of electromagnetic induction heat generation as a heated member heating rotary body.

Reference numeral 21 denotes a horizontal cylindrical film guide member. For example, it is a rigid molded product made of a heat-resistant resin.

Reference numerals 22 and 23 denote an excitation coil and a core as magnetic field generating means, which are disposed and held on the inner bottom of the film guide member 21. The exciting coil 22 is formed by winding a conducting wire into a boat shape substantially corresponding to the inner bottom shape of the film guide member 21. The core 23 is a ferromagnetic / high-permeability material, and is preferably a material used for a transformer core such as ferrite or permalloy.
It is preferable to use ferrite with little loss even at a frequency of 00 kHz or more. The core 23 is arranged and held on the inner bottom of the film guide member 21 at the center of the inner side of the boat-shaped exciting coil 22.

Numeral 24 denotes a cylindrical film material (hereinafter, referred to as a fixing film) having an electromagnetic induction and heat generation function as a member to be heated. The cylindrical fixing film 24 is provided with the exciting coil 22 and the core 23 as the magnetic field generating means as described above.
Cylindrical film guide member 2 in which is disposed and held inside
1 is loosely fitted outside.

Reference numeral 25 denotes an elastic pressing roller as a pressing member, which comprises a core metal 25a and an elastic material layer 25b made of silicone rubber or the like formed concentrically around the core metal.

A film guide member 21 having a cylindrical fixing film 24 loosely fitted thereon and a pressure roller 25
And the fixing film 24 are arranged vertically in parallel with each other.
And press-fit with a predetermined pressing force against the elasticity of the elastic material layer 25b of the pressure roller 25,
A heating nip portion (hereinafter, referred to as a fixing nip portion) n having a predetermined width is formed between the two portions 24 and 25.

Excitation coil 22 and core 23 as magnetic field generating means disposed and held inside film guide member 21
The lower surface of the core 23 is positioned corresponding to the fixing nip portion n.

In the apparatus of this embodiment, the pressure roller 25 is driven to rotate at a predetermined peripheral speed in a counterclockwise direction indicated by an arrow by a driving means M (pressure roller drive type). With the rotation of the pressure roller 25, the rotational force acts on the cylindrical fixing film 24 by the frictional force between the pressure roller 25 and the outer surface of the fixing film 24 in the fixing nip portion n, and the cylindrical fixing film 24 is fixed. Film 2
4 is a fixing nip portion n around the film guide member 21.
At this time, while the inner surface is in close contact with the lower surface of the film guide member 21, the film rotates in the clockwise direction indicated by the arrow at a peripheral speed substantially corresponding to the rotational peripheral speed of the pressure roller 25.

The film guide member 21 functions as a holding member for the excitation coil 22 and the core 23 as a magnetic field generating means, and also serves to pressurize the fixing nip portion n and to stabilize the rotation and transport of the cylindrical fixing film 24. I do. By interposing a small amount of lubricant such as heat-resistant grease in the sliding part of the film guide member 21 and the fixing film 24 in close contact with each other, the sliding resistance can be reduced and the fixing film 24 can be smoothly rotated.

An exciting circuit (not shown) as a power supply device is connected to the exciting coil 22. The excitation circuit is 20 kHz
A switching power supply can generate a high frequency from 500 kHz to 500 kHz, and the excitation coil 22 generates a high frequency magnetic flux by a high frequency current (alternating current) supplied from the excitation circuit. The high-frequency magnetic flux is concentrated and distributed to the fixing nip n and its vicinity by the core 23 corresponding to the position of the fixing nip n.

FIG. 3 is a schematic diagram showing a layer structure of the fixing film 24 having an electromagnetic induction heat generation property in this embodiment. The fixing film 24 of this embodiment has different colors of electromagnetic induction heat generation layers (hereinafter referred to as heat generation layers). 24a), an elastic layer 24b coated on the outer surface thereof, and a release layer 24c coated on the outer surface thereof. Heat generation layer 24
The a side is the inner side of the cylindrical fixing film 24, and the release layer 24c side is the outer side.

Heating layer 24a: nickel, iron, ferromagnetic SU
It is composed of a ferromagnetic metal layer (magnetic layer, resistor layer) having a thickness of 1 to 100 μm such as S, nickel-cobalt alloy or the like. It may be a film layer in which a metal filler is mixed in a resin.

Elastic layer 24b: The elastic layer is a layer provided so that the surface of the fixing film can follow the unevenness of the recording material and the toner layer introduced into the fixing nip portion n, and has a thickness of 10 to 500.
A material having good heat resistance and good heat conductivity, such as silicone rubber, fluorine rubber, fluorosilicone rubber of μm, etc. is used. The presence of the elastic layer 24b is particularly effective in the case of a heat fixing process of a color toner image layer of four-color superposition where the thickness of the toner layer is large.

Release layer 24c: A surface layer for improving the toner release property of the surface of the fixing film 24.
A material having good releasability and heat resistance, such as FA and fluororesin, is used, and has a thickness of 1 to 100 μm.

As described above, the excitation coil 22 generates a high-frequency magnetic flux by the high-frequency current supplied from the excitation circuit. The high-frequency magnetic flux is concentrated and distributed to the fixing nip n and its vicinity by the core 23 corresponding to the position of the fixing nip n. Then, the high-frequency magnetic flux F (FIG. 3) generates an eddy current a in the heating layer 24a of the fixing film 24 which has an electromagnetic induction heating property. The eddy current a generates Joule heat in the layer 24a due to the specific resistance of the heating layer 24a (heat generation due to eddy current loss). The heat generated by the heat generating layer 24a is conducted to the elastic layer 24b and the release layer 24c. That is, the fixing film 24 generates electromagnetic induction heat.

The electromagnetically induced heat of the fixing film 24 is intensively generated in the vicinity of the fixing nip n where the alternating magnetic flux is concentrated and distributed, and the fixing nip n is heated with high efficiency. The temperature of the fixing nip n is controlled such that a predetermined temperature is maintained by controlling power supply (current supply) to the exciting coil 22 by a temperature control system including a temperature measuring element (not shown).

Thus, the pressure roller 25 is driven to rotate,
Along with this, a cylindrical fixing film 24 as a member to be heated is rotated around the film guide member 21, and the power is supplied from the excitation circuit to the excitation coil 22 so that the fixing film 24 is heated by electromagnetic induction and fixed. In a state where the nip portion n rises to a predetermined temperature and the temperature is controlled, the recording material 15 on which the unfixed toner image T conveyed from the image forming portion (transfer portion) n is formed is fixed on the fixing film of the fixing nip portion n. The image surface faces upward between the pressure roller 24 and the pressure roller 25, that is, the image surface is introduced to face the outer surface of the fixing film 24, and the image surface adheres to the outer surface of the fixing film 24 and is fixed together with the fixing film 24. The nip n is nipped and conveyed. In the nipping and conveying process, the unfixed toner image T on the recording material 15 is heated by electromagnetic induction heat of the fixing film 24 and is fixed on the recording material surface by heating.

When the recording material 15 passes through the fixing nip n, the recording material 15 is separated from the outer surface of the rotary fixing film 14 by the separation claw 26, and is discharged and conveyed. Ta is a thermally fixed toner image.

As shown in FIGS. 2 and 4, the separation claw 26 is provided on the fixing film 24 at the recording material exit side of the fixing nip N.
A plurality of shafts 26a arranged substantially in parallel to the longitudinal direction of the fixing film 24 are supported at intervals along the longitudinal direction thereof. The recording material 15 that has come out of the fixing nip N at the tip of the separation claw 26 is separated from the outer surface of the fixing film 14.

(3) Life Detecting of the Fixing Film 24 The fixing film 24, which is the rotating member to be heated, is released as the surface layer as the number of sheets passed through the apparatus, that is, the number of rotations of the film, increases, that is, as the durability advances. Layer 24c
Is cut down entirely or locally (partially),
Eventually, the scraping reaches the elastic layer 24b, so that the fixing film 24 reaches its end of life.

The fixing film which has reached the end of its life is the release layer 24c.
Since the fixing is poorly generated at the portion which has been substantially removed and the portion is easily damaged, it is necessary to take measures such as replacement.

FIG. 5A shows the fixing film 24 at the beginning of the endurance, in a state where the release layer 24c is sufficiently present. FIG. 4B shows the fixing film 24 which has reached the end of its life due to the progress of its durability, in which the release layer 24c has been scraped down to the elastic layer 24b.

Reference numerals 27 and 28 denote sensors and control circuits as means for monitoring the film thickness of the fixing film 24 and detecting the life of the fixing film.

In this embodiment, the sensor 27 is a reflection density sensor, and the control circuit 28 detects the life of the fixing film 24 by monitoring the film thickness of the fixing film 24 in the form of reflection density. That is, while the release layer 24c exists or remains on the surface of the fixing film as shown in FIG. 5A during the progress of the durability of the fixing film 24, the sensor 27 determines the reflection density of the release layer 24c. Input to the control circuit 28. As the durability of the fixing film 24 advances, the scraping of the release layer 24c substantially reaches the elastic layer 24b as shown in FIG.
Is input to the control circuit 28.

Since the reflection densities of the release layer 24c and the elastic layer 24b of the fixing film 24 are different from each other, the endurance of the fixing film 24 shown in FIG. (B) As shown in FIG.
b until the sensor circuit reaches the point b.
In FIG. 8, the reflection density information of the release layer 24c is input as shown in FIG. 8C, but the control is performed after the scraping of the release layer 24c substantially reaches the elastic layer 24b as shown in FIG. The reflection density information of the elastic layer 24b is input to the circuit 28 as shown in FIG.

The control circuit 28 sends a signal from the sensor 27 to the elastic layer 2.
When the reflection density information 4b is input, the warning display means 29 is operated to warn the operator that the life of the fixing film 24 has expired. The warning display means 29 is a warning lamp, a warning buzzer, a liquid crystal display, or the like. Further, it is possible to activate the warning display means 29 and to perform an emergency stop of the image forming apparatus.

In this embodiment, the sensor 27 is provided with a plurality of separation claws 2 arranged and supported along the length of the shaft bar 26a.
The fixing film outer surface portion P (FIG. 4), to which the tip of the separation claw located in the middle of the shaft of No. 6 comes into contact, is arranged so as to be monitored. That is, the fixing device 7 of this embodiment
Then, when the fixing film 24 is viewed in the longitudinal direction, the shaft 2
A plurality of separation claws 26 disposed and supported along the length of 6a
The outermost surface of the fixing film, where the tip of the separation claw located in the middle of the shaft is in contact, has the greatest amount of shaving due to durability, and it is most likely that defective fixing or breakage occurs in this fixing film. Fast. Therefore, by monitoring the film thickness of the fixing film portion, that is, the reflection density with the sensor 27, it is possible to accurately detect the actual life of the fixing film 27.

With this configuration, as described above, for example, when the life of the fixing film 24 is detected based on the number of durable sheets, the life is detected earlier than the actual life of the film (during continuous printing). There is no problem that the service life is not detected even when the fixing failure occurs (during intermittent printing), and the correct service life of the fixing film can be detected.

FIG. 6 shows the results of an endurance test performed on a printer provided with the fixing device 7 of the present embodiment. The horizontal axis indicates the number of endurance sheets, and the vertical axis indicates the reflection density of the fixing film 24, and indicates the change in the reflection density when continuous printing durability and intermittent printing durability are performed.

As the sensor 27, a reflection densitometer manufactured by Tokyo Denshoku Co., Ltd. was used. Release layer 24c of fixing film 24
Is a fluororesin, and its reflection density is 1.3%.
The elastic layer 24b is made of silicon rubber, and its reflection density is 0.6%.

As the durability has advanced, the control circuit 2
When the reflection density information of the fixing film input to 8 was changed from that of the fluororesin to that of the elastic layer 24b, the life of the fixing film 24 was displayed.

In continuous printing durability, almost 300,000 sheets (27
At 90,000 rotations), the life of the fixing film was displayed, and in the intermittent printing durability, the life of the fixing film was displayed at about 250,000 (280 rotations).

As can be seen from FIG. 6, when the life of the fixing film 24 is to be detected based on the number of durable sheets, the number of durable sheets whose life is different depending on the sheet passing mode (continuous or intermittent). If 250,000 sheets are set, the life is detected 50,000 sheets earlier in continuous printing, and in intermittent printing, the life is actually reached before the life is detected, and fixing failure and film damage occur.

On the other hand, as in this example, by directly monitoring the thickness of the fixing film, the life of the fixing film could be accurately detected irrespective of the difference in the number of durable sheets depending on the paper passing mode.

Further, since the method of shaving the fixing film is generally different depending on the environmental change, it is possible to detect the film life more accurately by employing the method of monitoring the film thickness than by detecting the life based on the number of durable sheets. .

<Embodiment 2> (FIG. 7) In the present embodiment, the fixing device 7 of the above-described Embodiment 1 has a layered structure as shown in FIG. 7 as a cylindrical fixing film 24 as a rotating member to be heated. used. The other device configuration is the same as the fixing device 7 of the first embodiment.

That is, the fixing film 24 used in this example has a thickness of 10 to 100 μm of a resin such as polyimide or polyamide.
A film base layer (base film) 24d, an electromagnetic induction heat-generating layer (heat generation layer) 24a made of a metal such as Fe / Co or a metal such as Ni / Cu / Cr formed by plating. PFA / PTFE on top
This is an electromagnetic induction heat generating cylindrical film having a three-layer structure of a release layer 24c having a thickness of 1 to 100 μm, which is formed by mixing or independently forming a heat-resistant resin having good releasability. The film base layer 24d side is the inner surface side of the cylindrical fixing film 24, and the release layer 24c side is the outer surface side.

In the fixing film 24, the heat generating layer 24a, which is an electromagnetic induction heat generating layer, generates heat (heat generated by eddy current loss) by the action of high frequency magnetic flux, and the generated heat is transmitted to the release layer 24c.

Also in this embodiment, the sensor 27 monitors the reflection density on the surface of the fixing film 24 and inputs the reflection density information to the control circuit 28. During the durability of the fixing film 24, the sensor 27 inputs the reflection density of the releasing layer 24c to the control circuit 28 while the releasing layer 24c exists or remains on the fixing film surface. When the endurance of the fixing film 24 advances and the scraping of the release layer 24c substantially reaches the heating layer 24a which is the next layer, the sensor 2
7 inputs the reflection density of the heating layer 24a to the control circuit 28.

Since the release density of the release layer 24c of the fixing film 24 and the heat generation layer 24a are different from each other, the durability of the release film 24c progresses from the beginning of the endurance of the fixing film 24, and the release layer 24c is substantially scraped. The reflection density information of the release layer 24c is input to the control circuit 28 from the sensor 27 until the release layer 24a is reached, but after the release layer 24c is substantially scraped down to the elastic layer 24b, the control circuit 28 is a heating layer 2
The reflection density information 4a is input. When the reflection density information of the heat generating layer 24a is input from the sensor 27, the control circuit 28 activates the warning display means (29) to warn the operator that the life of the fixing film 24 has expired.

Also in this embodiment, the release layer 24c and the heat generating layer 2
By monitoring the reflection density of 4a and detecting the life of the fixing film 24, as in the case of the first embodiment,
Even when the life time of the fixing film 24 differs depending on the paper passing mode and the environment, the accurate actual life of the fixing film 24 can be detected.

<Embodiment 3> (FIG. 8) In the present embodiment, as shown in FIG. 8 (a), the image of the fixing film 24 as a heating member heating rotary body is obtained with respect to the fixing device 7 of Embodiment 1. A film rubbing member 30 is provided for rubbing the surface (outer surface) of the non-image area outside the area, and the film thickness of the fixing film non-image area surface Q rubbed by the rubbing member 30 is provided. Is monitored in the form of reflection density by a reflection density sensor 27 to detect the life of the fixing film 24.

The film rubbing member 30 of this example is made of an acrylic resin or the like and has a roller shape having a width of 10 mm and a diameter of 15 mm. The roller is rubbed against the surface of the non-image area portion of the fixing film 24 with a spring pressure of 10 g or less. The non-image area portion of the fixing film 24 is rubbed by the rubbing member 30 when the fixing film 24 rotates.

The fixing film 24 in this example is made of an electromagnetically induced heat-generating layer (heat-generating layer) made of Ni, Fe or the like and having a thickness of 1 to 100 μm, as shown in the layer structure model diagram of FIG.
12a, thickness 10-500μ made of silicon rubber or the like
non-image area portion of the fixing film on the side to be rubbed by the film rubbing member 30. The elastic layer 24b has a thickness of 1 to 100 μm and is made of PTFE or PFA. Is provided with an intermediate layer 24e between the elastic layer 24b and the release layer 24c. This intermediate layer 24e
Is a layer provided for detecting the life of the fixing film 24, and it is preferable to use a material having a reflection density extremely different from that of the release layer 24c.

With the endurance of the fixing film 24, the release layer 24c, which is the surface layer of the image area of the fixing film 24, is scraped off. The release layer 24c, which is a non-image area portion of the fixing film 24 and is a surface layer of the portion rubbed by the rubbing member 30, is also a release layer which is a surface layer of the image area portion along with the durability of the fixing film 24. It is cut at almost the same speed as 24c.

The sensor 27 monitors the reflection density of the surface of the non-image area of the fixing film 24, which is rubbed by the rubbing member 30, and inputs the reflection density information to the control circuit 28. During the durability of the fixing film 24, the sensor 27 inputs the reflection density of the releasing layer 24c to the control circuit 28 while the releasing layer 24c in the non-image area portion of the fixing film 24 exists or remains. As the durability of the fixing film 24 progresses, the scraping of the release layer 24c in the non-image area portion of the fixing film 24 substantially reaches the intermediate layer 24e as the next layer. The reflection density of the control circuit 28
To enter.

In the non-image area portion of the fixing film 24, since the reflection densities of the release layer 24c and the intermediate layer 24e are different from each other, the endurance of the fixing film 24 is advanced from the beginning of the endurance, and the release layer 24c is scraped. Is substantially the intermediate layer 24e
Till the sensor 27 is connected to the control circuit 28
, The reflection density information of the release layer 24c is input. After the removal of the release layer 24c substantially reaches the intermediate layer 24e, the reflection density information of the intermediate layer 24e is input to the control circuit 28. When the control circuit 28 receives the reflection density information of the intermediate layer 24e from the sensor 27, the warning display means (29)
To warn the operator that the life of the fixing film 24 has expired.

In this case, as described above, the fixing film 2
The scraping speed associated with the durability of the release layer 24c in the image area portion 4 and the scraping speed associated with the durability of the release layer 24c in the non-image area portion of the fixing film 24 that is rubbed by the rubbing member 30. Since the speeds substantially correspond to each other, the film thickness of the surface portion Q of the non-image area of the fixing film is measured by the sensor 27 in the form of reflection density.
, The life of the fixing film 24 can be detected almost exactly.

With this configuration, the film scraping speed varies in the longitudinal direction of the fixing film depending on the environment, the size of the material to be passed, and the like, and any portion has the first life. Even when it is not possible to predict whether or not the fixing film can be accurately detected, the pressing force of the rubbing member 30 is adjusted to adjust the scraping speed of the non-image area of the fixing film.

Even when the reflection densities of the release layer 24c and the elastic layer 24b or the heat generating layer 24a are equal, the life of the film can be reliably detected by detecting the reflection density of the intermediate layer 24e.

Furthermore, in the present embodiment, the rubbing member 30 is disposed at a position where the film can be viewed from the outside, and a marking indicating a specific color or life warning is provided on the intermediate layer 24e at that position. And so on.

The intermediate layer 24e and the marking are formed on the release layer 2
While 4c is present or remains, it is concealed by the release layer 24c and is not substantially visually recognized. However, the durability of the fixing film progresses, and the release layer 24c is substantially scraped to reduce the life of the fixing film. When it becomes, it appears and is visually recognized. Thereby, the user or service person can visually detect the life of the fixing film. In this case, the sensor 27 can be omitted, and the configuration can be simplified.

<Others> 1) In the heating device of the present invention, the rotating body that rotates and contacts the material to be heated to heat the material to be heated is the electromagnetic induction heating cylinder in the electromagnetic induction heating type heating device of the embodiment. Not limited to film-shaped film material, rotating heat roller (fixing roller) in heat roller type heating device, cylindrical or endless belt-shaped rotating film material (fixing film) in film heating type heating device, electromagnetic heating type Induction heating rotary fixing roller in the heating device,
Alternatively, a cylindrical or endless belt-like rotating film material (fixing film) containing a layer that generates electromagnetic induction due to the action of a magnetic field, or heat resistance without an electromagnetic induction heating layer
It may be a thin cylindrical or endless belt-shaped rotating film material (fixing film) or the like, and the life thereof can be accurately detected with the same configuration and principle as described above.

2) The heating apparatus of the present invention is not only an image heating and fixing apparatus in the image forming apparatus and the like of the embodiment, but also an apparatus for heating a recording material carrying an image to improve surface properties such as gloss. It can be widely used as a heat treatment device such as a device for temporary attachment and a device for drying or heat laminating a sheet.

[0099]

As described above, according to the present invention, a heating device having a rotating body that rotates in contact with a material to be heated and that heats the material to be heated is cut with a certain amount of durability and cut by a certain amount or more. By directly monitoring the thickness (scraping) state of the heated material heating rotary body that has reached the end of its life, it is detected that the film thickness has reached the film thickness state corresponding to the end of the life of the heated material heated rotating body. Accordingly, it is possible to accurately detect the actual life of the heated material heating rotary body regardless of the difference in the number of durable sheets due to the heated material passing mode or environmental change.

Further, a member for rubbing a part of the heated material heating rotary body is provided, and by monitoring the film thickness of the heated material heated rotary body rubbed by the rubbing member, it is ensured. It is possible to detect the actual life of the heated rotary member.

The detection that the film thickness of the heated material heating rotator has reached the film thickness state corresponding to the end of the life is detected, for example, when the heated material heating rotator is formed by laminating a plurality of layers. By monitoring a difference in optical properties between the outermost layer and a next layer below the outermost layer or a layer below the outermost layer, for example, a difference in reflection density, it can be easily and accurately detected.

In the above case, even when the reflectance of the outermost layer of the heated rotary member to be heated and the lower layer thereafter are close to each other and it is difficult to detect the difference in the reflection density by the sensor, the provision of the intermediate layer for detecting the life can be achieved. In addition, it is possible to easily and accurately detect the actual life of the heated rotary member.

Further, a rotating body life detecting layer having a different color from at least the other layers is provided on the heated material heating rotary body. For example, when the surface layer of the heated material heating rotary body is scraped off due to durability and is cut by a certain amount or more. By giving a specific color or a marking indicating a life warning to the appearing intermediate layer, a user or a serviceman can visually recognize the appearance of the intermediate layer and recognize that the heated material heating rotary body has reached the end of its life. Therefore, in the case of this configuration, a sensor for measuring the reflection density for monitoring the film thickness of the heated rotary member to be heated can be omitted, and the configuration can be simplified.

[Brief description of the drawings]

FIG. 1 is a schematic configuration model diagram of an example of an image forming apparatus.

FIG. 2 is a fixing device (image heating device) according to the first embodiment.
Schematic configuration model diagram of

FIG. 3 is a schematic diagram of a layer structure of a fixing film.

FIG. 4 is a schematic diagram of a fixing device viewed from a recording material exit side;

5 (a), (b) and (c) are diagrams for explaining the principle of fixing film thickness monitoring and life detection.

FIG. 6 is an endurance test result diagram of a printer including the fixing device of the first embodiment.

FIG. 7 is a schematic diagram illustrating a layer configuration of a fixing film in a fixing device according to a second embodiment.

8A is a schematic configuration diagram of a fixing device according to a third embodiment, and FIG. 8B is a schematic diagram of a layer configuration of a fixing film.

[Explanation of symbols]

7 Generic reference numeral of fixing device as image heating device 21 Film guide member 22/23 Exciting coil and core as magnetic field generating means 24 Electromagnetic induction heat generating cylindrical film material as heated rotating body for heated material 25 Pressure roller 26 Separation Claw 27 Reflection density sensor 28 Control circuit 29 Warning display means 15 Recording material as heating material n Fixing nip

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroki Kisu 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (12)

[Claims] In a heating apparatus having a rotating body that rotates and contacts a material to be heated to heat the material to be heated, a rotating body life detecting unit that monitors a film thickness of the rotating body and detects a life of the rotating body is provided. A heating device comprising: 2. A heating device having a rotating body that rotates and contacts a material to be heated and heats the material to be heated, wherein a rotating body life detecting means for monitoring the thickness of the rotating body and detecting the life of the rotating body. And a warning device which operates based on life detection information of the device. 3. The heating device according to claim 1, wherein the rotating body life detecting means includes an outermost layer and a lower layer below the outermost layer when the rotating body is configured by laminating a plurality of layers. A heating device characterized in that the difference in optical properties between the next layer and the subsequent lower layer is monitored to detect the life of the rotating body. 4. The heating device according to claim 3, wherein a difference in optical properties of the rotator constituting layer is a difference in reflection density. 5. The heating device according to claim 1, further comprising a member for rubbing a part of the rotating body, and monitoring a film thickness of the rotating body rubbed by the member. A heating device, characterized in that: 6. The heating device according to claim 5, wherein an intermediate layer for detecting the life is provided in a portion following the outermost layer below the outermost layer of the rotating body portion rubbed by the rubbing member. Heating equipment. 7. A heating device having a rotating body which rotates in contact with a material to be heated and heats the material to be heated, wherein the rotating body is provided with at least a rotating body life detecting layer different in color from other layers. Characteristic heating device. 8. The heating device according to claim 1, wherein the rotating body includes a layer that generates electromagnetic induction by the action of a magnetic field, and heats the material to be heated by the heat generated by the layer. Heating equipment. 9. The heating device according to claim 1, further comprising a pressing member that forms a nip portion with the rotating body, wherein a material to be heated is introduced into the nip portion, and the nip portion is conveyed to be heated. A heating device. 10. The image heating apparatus according to claim 1, wherein the material to be heated is a recording material carrying an image, and the apparatus heat-treats the image carried on the recording material. A heating device, which is a device. 11. The heating apparatus according to claim 10, wherein the image heating process is a heating and fixing process for an image on a recording material. 12. An image forming apparatus comprising the heating device according to claim 1 as an image heating device for heating and fixing an unfixed image on a recording material.