JP2001222174A - Heater for heating image, image heating device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten first printing time and to easily cope with the high speed operation of an image forming device in a heater for heating an image 11 excellent in quick starting ability, an image heating device equipped with the heater 11 and the image forming device equipped with the image heating device. SOLUTION: This heater for heating an image 11 is constituted by using a bowed metallic member at least one part of which is curved on its cross section as base material 15, and successively laminating an insulating layer 16 and an energizing heating resistance layer 17 in a bowed state on the curved inner surface side of the metallic member, The image heating device is provided with a rotatable cylindrical member 13 forming a fixing nip part N with a pressure member 20 and having a metallic sleeve as base material, and the member 13 is rotated while its inner surface rubs in contact with the curved outer surface of the heater 11. Then, the image forming device is equipped with the image heating device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image heating heater,
The present invention relates to an image heating device and an image forming device.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus employing an image forming process such as an electrophotographic system or an electrostatic recording system, a recording material (transfer material, printing paper, photosensitive paper, electrostatic recording paper, etc.) The fixing device as an image heating device for thermally fixing the unfixed toner image of the image information formed and carried by the transfer method or the direct method as a fixed image to the recording material on which the unfixed toner image is formed and carried by each other. An unfixed image is transferred onto a recording material by the heat of the fixing roller by being introduced into a nip formed by a fixing roller, which is a heat roller, which rotates by pressing and a pressing roller pressed against the fixing roller, and passed through the nip. A so-called heat roller type heat fixing device for fixing an image as a permanent image is widely used.

Further, a film heating type apparatus having features such as significantly shortening of a wait time (quick start property, on-demand property) and power saving as compared with a heat roller type heat fixing apparatus (Japanese Patent Laid-Open Publication No. 63-318
No. 2, Japanese Patent Application Laid-Open No. 2-1577878, Japanese Patent Application Laid-Open No.
No. 44076 / JP-A-4-204980) are also in practical use.

This film heating type image heating apparatus comprises an image heating heater (heating body), a film which slides on the heating body, and a pressing member which forms a nip with the image heating heater via the film. Wherein the recording material holding the image in the nip is nipped and conveyed, and the image on the recording material is heated by heat from the image heating heater via the film. A so-called ceramic heater having a low heat capacity and a rapid temperature rise is used as an image heating heater, and a heat-resistant and thin resin film such as polyimide is used as a film.

In order to further improve the quick start property of the film heating type image heating apparatus and to cope with the high speed operation,
There is also a method of using a thin metal film having good thermal conductivity instead of the resin film.

There is also a method of using a metal substrate heater having a heater substrate as a metal member as an image heating heater.

Japanese Patent Application Laid-Open No. 9-16004 discloses a heating device using a metal film and a metal substrate heater, which includes a fixed heater, a metal film sliding on the heater, and a nip portion between the metal film and the metal film. A heating device for heating the material to be heated while sandwiching and transporting the material to be heated between the metal film and the pressure member, wherein the heater has at least one metal layer and at least one insulator layer. There has been proposed a heating device having the above-described layer structure, in which a heating element is formed on the insulator layer, and the surface of the metal layer serves as a sliding surface of the metal film.

[0008]

In a film heating type image heating apparatus, when a cylindrical metal film is used and the inside diameter of the metal film is small, a flat surface formed by a pressing member and a heater surface is used. Since the metal film is introduced into the heating nip portion, and the metal film is constantly bent, the durability is reduced due to fatigue fracture.

In addition, when the radius of curvature of the metal film is increased to prevent fatigue damage due to bending of the metal film, the size of the apparatus is increased, and the outer diameter of even a thin metal film is increased. As a result, the heat capacity and heat radiation cannot be ignored, resulting in impaired quick start performance.

An object of the present invention is to solve the above-mentioned problems in a film heating type image heating apparatus using a metal film or a metal substrate heater, and to further improve the image heating apparatus. Satisfactory, even if the image forming apparatus is operated at high speed, without impairing these performances, it can be easily manufactured and secures uniform fixing performance of the toner image on the recording material, and achieves long-life heat fixing. An object of the present invention is to provide an image heating heater, an image heating device, and an image forming apparatus including the image heating device, which are capable of performing the above-described operations.

[0011]

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

(1) An arc-shaped metal member at least partially curved in a cross section is used as a base material, and an insulating layer and a current-carrying resistance layer are sequentially laminated in an arc shape on the inner side of the curved surface of the metal member. An image heating heater comprising: a heater;

(2) The image heating heater according to (1), wherein a filler made of a member having a higher thermal conductivity than the insulating layer is added to the insulating layer.

(3) the insulating layer is made of polyimide;
(2) The filler is at least one of BN, AlN, alumina, and insulating metal oxide.
3. The image heating heater according to claim 1.

(4) A sliding layer formed of a fluororesin, a dry film lubricant containing at least one kind of solid lubricant of molybdenum disulfide and graphite, or glass on the curved outer surface side of the metal member. The image heating heater according to any one of (1) to (3), wherein a (lubricating layer) is formed.

(5) The image heating heater according to (4), wherein a filler harder than the sliding layer is added to the sliding layer.

(6) The image heating heater according to (5), wherein the filler is at least one of glass beads, glass flakes, glass particles, silicon carbide, mica, and ceramic powder. .

(7) The image heating heater according to any one of (1) to (6), wherein a heat insulating layer is provided on the inner side of the curved surface of the energized heat generating resistance layer.

(8) The image heating heater according to (7), wherein the thermal conductivity of the heat insulating layer is lower than the thermal conductivity of the insulating layer.

(9) An image heating apparatus for heating an image on a recording material by nipping and transporting the recording material at a heating nip formed by mutual pressure contact between a heating member having an image heating heater and a pressure member. The heater for image heating, using a bow-shaped metal member at least partially curved in a cross section as a base material,
An image heating apparatus comprising: an insulating layer and a current-carrying resistance layer which are sequentially laminated in an arc shape on a curved inner surface side of the metal member.

(10) The image heating apparatus according to (9), wherein a filler made of a member having a higher thermal conductivity than the insulating layer is added to the insulating layer.

(11) The image heating apparatus according to (10), wherein the insulating layer is made of polyimide, and the filler is at least one of BN, AlN, alumina, and insulating metal oxide.

(12) On the curved outer surface side of the metal member,
Sliding layer (lubricating layer) made of fluororesin, dry film lubricant containing at least one solid lubricant of molybdenum disulfide and graphite, or glass
The image heating apparatus according to any one of (9) to (11), wherein

(13) The image heating apparatus according to (12), wherein a filler harder than the sliding layer is added to the sliding layer.

(14) The image heating apparatus according to (13), wherein the filler is at least one of glass beads, glass flakes, glass particles, silicon carbide, mica, and ceramic powder.

(15) A heat-insulating layer is provided on the inner side of the curved surface of the current-carrying resistance layer.
The image heating device according to any one of 4).

(16) The image heating apparatus according to (15), wherein the thermal conductivity of the heat insulating layer is lower than the thermal conductivity of the insulating layer.

(17) The heating member has a rotatable cylindrical member whose base is a metal sleeve forming a heating nip portion by pressing against the pressing member, and the inner surface of the cylindrical member is The image heating device according to any one of (9) to (16), wherein the image heating device rotates while contacting and rubbing the curved outer surface of the image heating heater.

(18) The image heating apparatus according to (17), wherein the metal sleeve as a base material of the cylindrical member is formed in a thickness range of 30 μm to 200 μm.

(19) The radius of curvature r of the curved outer surface of the image heating heater is equal to the radius of curvature r 'of the inner surface of the cylindrical member.
And an image heating device according to (17) or (18), wherein the relationship is 0.5r '≦ r ≦ 3r ′.

(20) The thickness of the metal member portion of the image heating heater corresponding to at least the heating nip portion is 0.5 to 2 times the thickness of the metal member portion corresponding to the center portion in the width direction of the heating nip portion. The image heating device according to any one of (9) to (19), wherein the image heating device is formed with a thickness twice as large.

(21) The image heating device according to any one of (9) to (20), which is a heat fixing device for fixing an unfixed image as a permanent image on a recording material.

(22) An image forming apparatus comprising the image heating device according to any one of (9) to (21).

<Operation> A heating / fixing apparatus for heating an image on a recording material by nipping and conveying the recording material at a fixing nip portion formed by mutual pressure contact between a fixing member having an image heating heater and a pressing member. More specifically, as an example, the fixing member includes a metal sleeve (cylindrical member) having a thickness of 30 μm to 200 μm, and a current-carrying resistance layer, and has a cross-sectional arcuate shape in contact with the inner surface of the metal sleeve. A heating and fixing device including a curved and curved image heating heater.

Further, the curved surface type image heating heater has a thermal conductivity in the range of 0 ° C. to 250 ° C. in a direction opposite to the fixing nip portion of an arcuately curved metal high heat conductive substrate having 20 W / m · K or more. An insulating layer and a current-carrying resistance layer are sequentially laminated on the inner surface side of the arcuate curve, and a primer layer and a fluororesin having good slidability are provided on the outer side of the arcuate curve in the same direction as the fixing nip portion.
A dry film lubricant and the like are sequentially formed.

The metal high thermal conductive substrate of the curved surface type image heating heater has a heat capacity per unit volume of 5.0.
The metal member is J / cm ³ · K or less and has a total volume of 3 cm ³ or less, and has a substantially uniform thickness at least at a position corresponding to the fixing nip portion.

Thus, the contact heating is performed by the low-heat-capacity curved-type image heating heater that heats only the vicinity of the fixing nip portion from the inner surface of the low-heat-capacity metal sleeve having good thermal conductivity, thereby satisfying the quick start property. And the first print time can be shortened.

That is, power supply to the image heating heater can be shut down during standby when the image forming apparatus is not receiving a print signal, and energy-saving heat fixing can be realized.

Further, even when the power of the image forming apparatus is turned on from a room temperature state, since the heat capacity of the image heating heater is small, the print signal can be received immediately, so that the operator does not have to wait.

In addition, since the time required for heating the fixing nip to a temperature required for heat fixing after the image forming apparatus receives the print signal until the recording material reaches the fixing nip can be shortened, the first printing is performed. Time can be reduced.

Further, even when the image forming apparatus is operated at a high speed, the heating and fixing are performed only in the vicinity of the fixing nip, so that the heat fixing can be performed with high thermal efficiency.

Even when a thin metal sleeve is used, the image heating heater that is in contact with the inner surface has a curved shape, so that the metal sleeve does not bend repeatedly to cause fatigue damage. Thus, stable heat fixing can be performed for a long period of time.

Further, since the metal high thermal conductive substrate is provided between the energizing heat generating resistance layer of the image heating heater and the metal sleeve, temperature unevenness is reduced in the longitudinal direction of the image heating heater, and the recording material is reduced. Uniform fixing performance of the upper toner image can be obtained.

Further, the metal high thermal conductive substrate has an arcuate curve at least in the fixing nip portion, and has a substantially constant thickness at a portion corresponding to the fixing nip portion. In order to transfer the heat to the metal sleeve via the high thermal conductive plate having a substantially uniform thickness in the recording material conveyance direction, heat can be applied substantially uniformly in the recording material conveyance direction.
There is no heating unevenness such as abnormal heating during unloading. For this reason, for example, the recording material is not heated abnormally when it is discharged from the fixing nip portion, so that the toner image on the recording material does not solidify and a high-temperature offset does not occur.

Further, since the fixing nip portion is formed in an arcuate curved shape, it is possible to reduce the thickness even with a high heat conductive substrate made of metal having a small radius of curvature, thereby suppressing the heat capacity. Therefore, it is possible to reduce the size of the device and to obtain a configuration excellent in quick start performance.

Further, since the insulating layer interposed between the arcuately curved metal high thermal conductive substrate of the image heating heater and the energized heat generating resistive layer does not rub, the initial dielectric breakdown voltage is satisfied. For example, since it is not scraped due to durability, it can be formed to be thin, and a decrease in thermal efficiency can be suppressed.

Further, by mixing a high heat conductive filler into an insulating layer interposed between the high heat conductive substrate of the curved surface type image heating heater and the energized heat generating resistance layer, the thermal efficiency can be further improved. In particular, since there is no scraping due to rubbing, more conductive filler can be added as long as the dielectric strength is satisfied.

Also, a slidable member formed on the high thermal conductive substrate of the image heating heater that rubs against the metal sleeve, or an intervening member between the slidable member and the high thermal conductive substrate for increasing the adhesive force. By mixing a filler as an anti-wear agent into at least one of the primer layers, it is possible to further extend the life.

Further, in the direction opposite to the fixing nip portion of the current-generating resistance layer of the above-mentioned curved type image heating heater, the insulating property is higher than that of the insulating layer interposed between the high heat conductive substrate and the current-generating resistance layer. By forming a member or providing a gap, heat generated by energization of the energized heat generating resistance layer can be supplied to the fixing nip portion with high efficiency, and the fixing performance can be further improved.

Therefore, it is possible to configure a heat fixing device that satisfies the quick start property even when the image forming apparatus is further speeded up and has a reduced first print time.

[0051]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment (FIGS. 1 to 7) (1) Schematic Configuration of 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 printer or a copying machine using a transfer type electrophotographic process.

1 is a photosensitive drum as an image carrier,
A photosensitive material such as OPC, amorphous Se, and amorphous Si is formed on a cylindrical base such as aluminum or nickel. The photosensitive drum 1 is driven to rotate in a clockwise direction indicated by an arrow at a predetermined peripheral speed (process speed).

Charging Step: First, the surface of the rotary photosensitive drum 1 is uniformly charged to a predetermined polarity and potential by a charging roller 2 to which a predetermined charging bias voltage is applied as a charging device.

Exposure step: Next, the charged surface of the rotating photosensitive drum 1 is subjected to scanning exposure by a laser beam 3 which is ON / OFF controlled according to image information by an image exposure means (not shown), for example, a laser beam scanner. You. This allows
An electrostatic latent image corresponding to the scanning exposure pattern is formed on the surface of the rotating photosensitive drum 1.

Developing step: The electrostatic latent image is developed by the developing device 4 as a toner image. As a development method, a jumping development method, a two-component development method, an FEED development method, or the like is used, and a combination of image exposure and reversal development is often used.

Transfer step: The toner image on the surface of the rotating photosensitive drum 1 is transferred onto the recording material P at a transfer nip portion where the transfer roller 5 as a transfer device and the photosensitive drum 1 are in contact with each other.

The transfer roller 5 is brought into contact with the photosensitive drum 1 at a predetermined pressure, and rotates in the forward direction of the photosensitive drum 1 at a peripheral speed substantially equal to the peripheral speed of the photosensitive drum 1. Further, a predetermined transfer bias voltage is applied. The recording material P is fed from a paper feeding mechanism (not shown) to a transfer nip at a predetermined control timing, and is nipped and conveyed by a fixed pressing force of a fixing nip formed by the photosensitive drum 1 and the transfer roller 5. .

Here, the sensor 8 conveyed from the paper feed mechanism to the transfer nip so that the image forming position of the toner image on the photosensitive drum 1 and the writing position of the leading end of the recording material coincide.
Detects the leading edge of the recording material and adjusts the timing.

Fixing step: The recording material P to which the toner image has been transferred at the transfer nip portion is separated from the surface of the rotary photosensitive drum 1 and conveyed to a heat fixing device (image heating device) 6 where the toner image is converted into a permanent image. It is established as.

Cleaning step: On the other hand, the transfer residual toner remaining on the photosensitive drum 1 is removed from the surface of the photosensitive drum 1 by the cleaning device 7. The photosensitive drum 1 is repeatedly used for image formation.

(2) Heat Fixing Apparatus 6 A) Overall Schematic Configuration of Heat Fixing Apparatus 6 The heat fixing apparatus 6 of this embodiment is a fixing sleeve type apparatus using the image heating heater according to the present invention. FIG. 2 is an enlarged model diagram of the heat fixing device 6, and FIG. 3 is an enlarged model diagram of the vicinity of the fixing nip portion.

Reference numeral 10 denotes a fixing member (heating member), which is a heat insulating stay holder (support) 12 having a substantially semicircular trough-shaped cross section.
And a heater (heating body) 11 as a heating member disposed substantially in the center of the lower surface of the stay holder 12 along the longitudinal direction of the holder, and loosely and externally fitted to the stay holder 12 provided with the heater 11 with a margin. This is an assembly including a fixing sleeve (cylindrical member) 13 which is a metal fixing film having a small heat capacity as a whole.

Numeral 20 denotes an elastic pressure roller as a pressure member, which presses against the lower surface of the heater 11 under the fixing member 10 with the fixing sleeve 13 interposed therebetween to form a fixing nip portion N having a predetermined nip width. Form.

The fixing sleeve 13 and the pressure roller 20 are driven to rotate at a predetermined peripheral speed in the direction of the arrow, and the fixing sleeve 13 rotates while its inner surface rubs against the lower surface of the heater 11 and the outer surface of the stay holder 12.

The heater 11 generates heat when energized, and is heated and controlled at a predetermined temperature by a temperature control system.

The fixing sleeve 13 and the pressure roller 20 are rotated, the heater 11 is energized, the temperature of the heater rises, and the heat causes the fixing nip N to rise to a predetermined fixing temperature, and the temperature is adjusted. At the fixing nip N
The recording material P having an unfixed toner image formed thereon is guided by a heat-resistant fixing entrance guide 26a and introduced. The introduced recording material P is nipped and conveyed at the fixing nip N, and is heated by the heater 11 via the fixing sleeve 13 during the passage of the fixing nip.
As a result, the unfixed image is melted by the heat and is fixed as a permanent image on the recording material.

Thereafter, the recording material exiting the fixing nip N is guided by a heat-resistant fixing discharge guide 26b and discharged onto a discharge tray (not shown).

The details of the structure of the heater 11 will be described in the following section B).

The stay holder 12 has a function of holding the heater 11 and preventing heat radiation in the direction opposite to the fixing nip portion N side, and includes a liquid crystal polymer, a phenol resin, a PPS,
The fixing sleeve 13 is made of a heat-resistant resin such as PEEK. The fixing sleeve 13 is loosely fitted to the fixing sleeve 13 as described above, and is rotatably disposed.

Since the inner surface of the fixing sleeve 13 rotates while rubbing against the heater 11 and the stay holder 12 inside the fixing sleeve, it is necessary to reduce the frictional resistance between the heater 11 and the stay holder 12 and the fixing sleeve 13. . Therefore, a small amount of lubricant such as heat-resistant grease is interposed on the surfaces of the heater 11 and the stay holder 12. Thus, the fixing sleeve 13 can rotate smoothly.

FIG. 4 is a schematic diagram of the layer structure of the fixing sleeve 13. The fixing sleeve 13 has a total thickness of 200 μm or less to enable quick start, and has heat resistance,
The base layer is a metal sleeve 13a having a base layer of a metal member such as SUS, Al, Ni, Cu, Zn or the like having high thermal conductivity alone or in an alloy state. Further, the metal sleeve 13a having sufficient strength and excellent durability to constitute a long-life heat fixing device needs to have a total thickness of 30 μm or more. Therefore, the total thickness of the metal sleeve 13a is optimally 30 μm or more and 200 μm or less.

Further, in order to prevent offset and ensure the separation of the recording material, the surface layer is made of PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene perfluoroalkyl vinyl ether copolymer), FEP
Release of fluororesins such as (tetrafluoroethylene hexafluoropropylene copolymer), ETFE (ethylenetetrafluoroethylene copolymer), CTFE (polychlorotrifluoroethylene), PVDF (polyvinylidene fluoride), and silicone resin The releasable layer 13c is coated with a heat-resistant resin having good properties or alone.

As a coating method, a metal sleeve 13 is used.
After the outer surface of a is etched, the release layer 13c is formed by dipping, powder spraying or the like, or a tube-shaped release layer is applied to the surface of the metal sleeve 13a. May be.
Alternatively, after blasting the outer surface of the metal sleeve 13a, a primer layer 13b as an adhesive may be applied to cover the release layer 13c.

Further, a highly lubricious fluororesin layer or the like may be formed on the inner surface of the metal sleeve 13a which comes into contact with the heater 11.

The elastic pressing member 20 is made of SUS, SUM, A
and an elastic layer 22 formed by foaming heat-resistant rubber such as silicon rubber or fluorine rubber or silicon rubber on the outside of a metal core 21 made of Pl, PFA, PTFE,
A release layer 23 such as FEP may be formed.

The pressure roller 20 is sufficiently pressed from the both ends in the longitudinal direction by a pressing means (not shown) in the direction of the fixing member 10 so as to form nip portions N required for heat fixing.

B) Heater 11 FIG. 5 (a) is a plan model view of the back side (inner side) of the heater 11, and FIG. 5 (b) is an enlarged transverse section taken along line (b)-(b) of FIG. It is a model figure.

The heater 11 is a horizontally long, narrow, thin, thin wall member whose longitudinal direction is perpendicular to the conveying direction of the recording material P, and has a low heat capacity as a whole. Metal substrate (heater substrate) 15 whose cross-sectional shape is curved in an arc shape (arc shape) 15 b. The inner side of the curved surface of the metal substrate 15 (fixing nip N
The insulating layer 16 is formed on the side opposite to the side) so as to have an arcuate cross-section in line with the curved inner surface. C. A current-generating resistor layer 17 is formed on the insulating layer 16 along the longitudinal direction of the insulating layer and is formed in an arcuate cross section along the curved inner surface of the insulating layer, and at both ends of the current-generating resistor layer 17. Power supply electrode portions 25a and 25 provided in a conductive state
b, d. Curved outer surface side of metal substrate 15 (fixing nip N side)
And a sliding layer (lubricating layer) 18 and the like.

Further, a temperature detecting element 14 such as a thermistor for detecting a heater temperature is disposed substantially at the center of the rear side of the heater 11 in the longitudinal direction of the heater.

A groove 12a (FIG. 3) having a cross-sectional shape substantially corresponding to the cross-sectional shape of the heater 11 is formed substantially at the center of the lower surface of the heat-insulating stay holder 12 along the length of the holder. The heater 11 has the groove 12
a.

The power supply connectors 31 communicating with the power supply circuit 30 are provided at both ends of the heater 11.
The power supply contacts on the connector side are in contact with the power supply electrodes 25a and 25b at both ends of the current-carrying resistance layer 17 on the heater 11, and the power supply circuit 30 and the heater 11 are electrically connected. Connected.

Reference numeral 32 denotes a control circuit. This control circuit 32
, The heater temperature detection signal of the temperature detection element 14 is input. From the power supply circuit 30 via the connectors 31a and 31b, the power supply electrode portion 25a of the electric heating resistor layer 17 of the heater 11
When a voltage is applied to the first and second heaters 25b, the energized heat generating resistance layer 17 generates heat, and the generated heat causes the temperature of the heater 11 to rise.
The temperature rise of the heater 11 is detected by the temperature detection element 14, and a heater temperature detection signal is input to the control circuit 32. The control circuit 32 appropriately controls the duty ratio, the wave number, and the like of the voltage applied from the power supply circuit 30 to the heater 11 in accordance with the input heater temperature detection signal, so that the fixing nip portion N
Temperature so as to keep the temperature substantially constant at a predetermined fixing temperature,
The heater heating necessary for fixing the toner image on the recording material P is performed.

A) Metal substrate 15 The metal substrate 15 serving as a heater substrate has a thermal conductivity of 0 ° C. or less.
SUS, Al, C which is a high thermal conductive substrate of 20 W / m · E or more in the range of 250 ° C. and which has a curved cross section in an arc shape
It is a horizontally long, narrow, and thin plate member made of a metal material such as u, Ni, Zn, or an alloy material.

The width of the metal substrate 15 is equal to or larger than the width of the fixing nip N.

Further, the thickness of at least a portion corresponding to the width of the fixing nip portion N of the metal substrate 15 is kept substantially constant, and the toner image on the recording material P is heated and fixed via the small-diameter fixing sleeve 13. In this case, it is formed such that heating can be uniformly performed in the fixing nip portion with a low heat capacity.

The radius of curvature r of the arcuate cross-section of the metal substrate 15 is in a relationship of 0.5r ′ ≦ r ≦ 3r ′ as compared with the radius r ′ (inner diameter) of the fixing sleeve 13. This makes it possible to prevent the fixing sleeve 13 made of a metal material from being fatigued and damaged due to bending at the fixing nip portion N of the fixing sleeve 13, thereby extending the life of the fixing sleeve 13 and increasing the heater 11. Heat from the fixing sleeve 1
3 can be provided sufficiently.

The thickness of the metal substrate 15 needs to be small in order to maintain the quick start property, and the heat capacity member per unit volume of 5.0 J / cm ³ · K or less is required. The thickness is preferably set to 3 cm ³ or less, and if the workability of the metal substrate 15 is in a favorable range, it is desirable to form the metal substrate 15 thinner.
Therefore, it is desirable to set the thickness to be not less than 50 μm and not more than 1 mm.

Further, even when there is unevenness in resistance in the longitudinal direction of the current-generating resistance layer 17, the unevenness in temperature is eliminated when the fixing nip portion N is heated because the thermal conductivity of the metal substrate 15 is high. This makes it possible to uniformly heat the recording material P over the longitudinal direction of the heater 11.

In the case where only the fixing nip portion N side of the metal substrate 15 is formed in an arc shape in cross section while the size of the heat fixing device 6 is kept small, and the opposite side is flat, the fixing is performed. If the metal substrate is formed with a width approximately equal to the nip width, the thickness becomes extremely large, which causes an increase in heat capacity. Further, the thickness of the metal substrate is different within the width of the fixing nip portion N. In particular, the thickness of the upstream portion of the fixing nip portion where the recording material enters and the thickness of the downstream portion of the fixing nip portion where the recording material is discharged are reduced. For example, since the toner image on the recording material is abnormally heated at the fixing nip outlet, the toner image loses viscosity and causes high-temperature offset. Also, when abnormal heating is performed on the upstream side of the fixing nip portion, the moisture in the recording material is rapidly released, and the pressure causes the toner image on the recording material to scatter behind the recording material (hereinafter referred to as tailing). Occurs).

Therefore, the thickness of the metal substrate 15 is preferably substantially constant at least at a position corresponding to the fixing nip portion in a cross section, or is preferably an arcuate curved shape such that the thickness of the metal substrate 15 is increased on the upstream and downstream sides of the fixing nip portion.

B) Insulating layer 16 The insulating layer 16 is made of polyimide, polyamide imide, PEE
K, PPS, heat-resistant resin such as liquid crystal polymer, and insulating material such as ceramic paint. 10μm ~ 100μ thickness
m.

C) Electric heating layer 17 The electric heating layer 17 is made of, for example, Ag / Pd (silver palladium), Ni / Cr, RuO ₂ , Ta ₂ N, or TaSiO.
Conductive heating resistive layer material (conductive paste) consisting of a conductive agent such as ₂ and a matrix component such as glass or polyimide is screen-printed into a 10-μm-thick, 1- to 5-mm-wide, line-shaped or narrow-band-shaped pattern. Can be formed by coating.

Further, it can be constituted by vapor deposition, sputtering, plating, metal foil or the like.

The electric heating resistance layer 17 is adjusted to a desired resistance value by optimizing the thickness and width.

Similarly, the power supply electrodes 25a and 25b can be formed by screen printing using, for example, an Ag paste.

The heat-generating resistance layer 17 and the power supply electrode 25a
25b is electrically insulated from the metal substrate 15 by the insulating layer 16.

The pattern of the current-carrying resistance layer 17 can have various forms. FIG. 5A shows a waveform pattern.

Further, as shown in FIG. 6, a plurality of energizing heating resistance layers 17a and 17b are provided, and a first energizing heating layer formed so as to be longer than the width of the maximum size recording material that can be passed through the image forming apparatus. At least one heat-generating resistor layer 17a and at least one second current-generating resistor layer 17b shorter than the width of the recording material having the maximum size are formed, and the current-generating heat-generating layer for energizing according to the size of the conveyed recording material is formed. You may make it selectable. In this case, the electrode portions 2 connected to the respective lengths of the current-carrying resistance layers 17a and 17b
Electric current is supplied to the current-carrying resistance layer through 5a and 25b and 25a 'and 25b'. Thus, since the heating area can be selected according to the width of the recording material P, it is possible to achieve a problem such as suppressing the temperature rise in the non-sheet passing portion.

In order to adjust the resistance value, the above-mentioned energized heat-generating resistance layer can be processed and corrected to an optimum line width by a method such as laser trimming, which is an effective means for achieving a more stable heating system. is there.

D) Sliding Layer 18 The sliding layer 18 is formed on the outer side of the curved surface of the metal substrate 15, that is, on the fixing sleeve 13 on the fixing nip portion N side of the metal substrate 15.
Is a lubricating material layer provided in a portion that rubs against the inner surface of the substrate.

For example, PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene perfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene hexafluoropropylene copolymer), ETFE (ethylene tetrafluoroethylene copolymer) , A fluororesin layer such as CTFE (polychlorotrifluoroethylene), PVDF (polyvinylidene fluoride), etc., alone or mixed, or a dry film lubricant made of graphite, molybdenum disulfide, etc., glass, etc. It can be formed and provided by coating.

As described above, the heater 11 in this embodiment is
Is formed in such a manner that an insulating layer 16 and a current-carrying resistance layer 17 are sequentially laminated in an arcuate manner on a curved inner surface side of a metal substrate 15 which is a high thermal conductive substrate, and a sliding layer 18 is formed on the curved outer surface side of the metal substrate 15.
Is formed, and the overall heat capacity of the heater 11 is realized by forming each layer thinly. That is, since the thickness of each layer can be reduced regardless of the radius of curvature of the metal substrate 15 on the fixing nip portion N side, the heat capacity of each layer can be reduced. In particular, a reduction in heat capacity by the metal substrate 15 and a reduction in the thickness of the insulating layer 16 generally having poor thermal conductivity are advantageous from the viewpoint of thermal efficiency. However, the insulating layer 16 is composed of the metal substrate 15, the current-carrying resistance layers 17, 17a, 17b, and the power supply electrode portions 25a, 2
It is necessary to satisfy the dielectric strength between 5b, 25a 'and 25b', and it is desirable that the thickness is about 10 μm to 100 μm and formed as thin as possible within the range that satisfies the dielectric strength.

As described above, in the present embodiment, the insulating layer 16 and the insulating layer 16 are provided on the curved inner surface side of the metal substrate 15 which has high thermal conductivity and low heat capacity and at least a portion corresponding to the fixing nip portion N has an arcuate cross section. Electric heating resistor layer 17 (17a
17b) to form the heater 11,
It is possible to realize a heating heater having a high quick start property, and even if there is uneven resistance in the current-carrying resistance layers 17 (17a and 17b), the metal substrate 1 which is a high heat conductive substrate
5 has the function of diffusing the amount of heat and equalizing the temperature, so that the heater 11 can be uniformly heated in the longitudinal direction.

Further, the heat from the heater 11 is transferred to the fixing sleeve 1 made of a metal sleeve having high thermal conductivity as a base material.
Since the heat is transmitted to the fixing nip N through the fixing member 3, heat loss can be reduced, and heat can be transmitted to the fixing nip N at a high speed even when the image forming apparatus is operated at high speed.
We can respond enough.

C) Experimental results for confirming the effects In order to confirm the above effects, the following are shown.
Was conducted.

. Relationship between the material and heat capacity of the metal substrate 15 of the heater 11 and the fixing performance at each conveying speed of the recording material. Relationship between the material of the metal substrate 15 of the heater 11, the temperature rise rate of the fixing nip, and the temperature distribution in the longitudinal direction. Relationship between the material and heat capacity of the thin fixing film or the fixing sleeve 13 interposed between the heater 11 and the fixing nip portion N and the fixing nip portion heating rate. Durability and fixing performance with respect to the relationship between the radius of curvature of the heater 11 on the side of the fixing nip N of the metal substrate 15 and the radius of curvature of the inner surface of the fixing sleeve 13. Relationship between Thickness of Metal Substrate 15 of Heater 11 Corresponding to Fixing Nip N and Stability of Fixing Performance Details of the experiment for clarifying the above relationship will be described below.

[Experimental Results] As a basic structure, the structure of the heater 11 was the same except for the substrate 15. On the surface of the heater substrate 15 opposite to the fixing nip N side, 20 μm polyimide was used as the insulating layer 16. It is formed by dipping and baking at 350 ° C., and the heating and heating resistance layer 17 is formed by mixing a mixture of a conductive agent of Ag / Pd and a phosphate glass as a matrix component with an organic solvent, a binder, a dispersant, and the like. The paste was then screen-printed and fired at 400 ° C.

A sliding layer 18 was formed by spray coating a 10 μm PFA resin layer on the fixing nip portion N side of the heater substrate 15.

The fixing sleeve 13 has an inner diameter of 30 mm.
・ Cylindrical aluminum (metal sleeve) 13 with a thickness of 50 μm
The primer layer 13b was formed into a cylindrical shape having an outer diameter of 30.13 mm by applying a primer layer 13b of 5 μm and a PFA resin (release layer) 13c by 10 μm dipping.

The pressure roller 20 was formed by forming a silicon rubber layer with a thickness of 5 mm as an elastic layer 22 on an Al core 21 having a diameter of 20 mm, and further covering the outer layer with a PFA tube as a release layer 23.

In the experiment, the recording material conveyance speed of the image forming apparatus was set to be freely changeable between 200 mm / sec and 250 mm / sec, and the fixing performance at each speed was determined by applying a pressure of about 0.5 N (50 g) to the cellophane tape. ), The cellophane tape was peeled off, and judgment was made from the image defect rate at that time.

The fixing performance was averagely sampled from the leading edge to the trailing edge and the left and right edges of the conveyed recording material.

It should be noted that the base film 63a (FIG. 10) of the fixing film was fixed to 50 by the conventional heat fixing apparatus of the film heating type.
μm polyimide, 5 μm primer layer 6 on its outer surface
In the case where a 10 μm PFA resin was formed as the release layer 3b and the release layer 63c, the fixing performance was already 200 mm / sec and the fixing was poor. At this time, the heater 61 used was one in which an energization heating resistance layer was screen-printed on a ceramic substrate to form a glass layer of 50 μm.

The experimental results are shown in Tables 1 to 4. In the table, ○ indicates good fixability, Δ indicates acceptable fixability, and X indicates poor fixation. The unit of thermal conductivity in the table is W / m · K, and the unit of heat capacity is J which is the product of heat capacity and volume per unit volume.
/ K. Further, 700 W of electric power was applied to the energized heating resistor layer 17 of the heater 11. The thermal conductivity in the table is 20 ° C
It is the average of the values measured between ３００300 ° C. and shows a thermal conductivity that differs by about ± 20% depending on the temperature (the same applies to the thermal conductivity values shown below).

1) Table 1... Heater substrate 1 of heater 11
Material difference 5 The substrate 15 of the heater 11 is 250 mm long, 10 mm wide,
The thickness was 1 mm. The recording material conveyance speed is 200 mm /
In 10 seconds after the power supply to the heater 11 was started, the recording material P carrying the unfixed toner image was inserted into the fixing nip portion N.

[0116]

[Table 1]

2) Table 2—Differences in recording material transport speed and material The recording material transport speed is 250 mm / s for the materials described in 1) above.
ec. The timing for inserting the recording material P into the fixing nip N was set to 7 seconds after the start of energization. In general, when the recording material transport speed increases, the amount of heat to be supplied may be insufficient, and the fixing performance decreases as the recording material transport direction becomes more rearward.

[0118]

[Table 2]

3) Table 3 Differences in heat capacity of materials In the configuration of the above 1), the thickness of the substrate 15 of the heater 11 was varied to compare the difference in heat capacity. Other conditions were the same as in 1).

[0120]

[Table 3]

4) Table 4... Difference between the recording material transport speed and the heat capacity of the material The heat capacity is varied depending on the thickness of the substrate in the same manner as in 3), and the recording material transport speed and the insertion of the recording material into the fixing nip are 2 )
The experiment was carried out under the same conditions.

[0122]

[Table 4]

According to the above experiments, first, it can be seen from experiments 1) and 2) that the higher the thermal conductivity of the substrate 15 of the heater 11, the better the fixing performance. Good fixing performance is obtained even when the recording material is conveyed at a speed higher than the recording material conveyance speed of 150 mm / sec in which the fixing failure has occurred in the conventional example. From this, the current-carrying resistance layer 1
By transferring the heat of 7 faster to the fixing nip N,
It can be seen that it is possible to cope with high-speed fixing performance.

Further, from the experiments 3) and 4), the heater 1
It can be seen that better fixing performance can be obtained by reducing the heat capacity of the first substrate 15. Particularly, in the case of a high-speed image forming apparatus that requires quick start, the time required for the recording material P to reach the fixing nip N is short,
The heat conductivity and heat capacity of the toner greatly affect the fixing performance.
Therefore, as long as the workability of the substrate 15 of the heater 11 is satisfied,
It is desirable to form it thinly.

In this experiment, an experiment was also conducted on a heater using a ceramic member having good thermal conductivity as a heater substrate. However, it is extremely difficult to manufacture a substrate having a curved cross section and high dimensional accuracy. Therefore, the cost is also increased.

Accordingly, as the high thermal conductive substrate 15 of the heater 11, a metal material or an alloy material having good workability is suitable.

[Experimental Results for] The experimental results for the following are shown in Table 5. The device configuration and the like are the same as those in the above experiment. The substrate 15 of the heater 11 was formed of various materials and had a length of 250 mm, a width of 10 mm, and a thickness of 1 mm.
The recording material conveyance speed was set to 200 mm / sec, and the temperature (nip temperature) of the fixing nip N was measured 5 seconds after the power supply to the heater 11 was started. As a measuring method, the temperature was measured by sandwiching a thermocouple in the fixing nip portion N.

[0128]

[Table 5]

As described above, the rate of temperature rise of the fixing nip N differs due to the difference in thermal conductivity, and the temperature of the fixing nip N can be raised more quickly by using the heater substrate 15 having higher thermal conductivity. become. Further, it can be seen that the temperature inside the fixing nip N can be increased more quickly when the heat capacity of the substrate 15 is reduced. This is the heating resistance layer 17
This is because the ratio of the amount of generated heat used to warm the substrate 15 decreases.

The temperature distribution in the longitudinal direction in the fixing nip N was measured using the heater 11 on which the heating resistor layer 17 having the waveform pattern shown in FIG. 5A was formed. The material of the heater substrate 15 is the above glass and aluminum. The temperature distribution was measured when the thermistor 14, which is a temperature detecting means disposed on the back side of the current-carrying resistance layer 17 of the heater 11, was kept at a constant temperature of 203 ° C.

FIG. 7 shows the measurement results. FIG. 7 shows that the use of a substrate having a high thermal conductivity (aluminum substrate) keeps the temperature distribution in the longitudinal direction substantially uniform. From this, when observing the fixing performance in the width direction of the recording material, when the heater 11 using aluminum for the substrate 15 obtains a uniform fixing performance, when the glass substrate is used, It was found that fixing unevenness occurred.

[Experimental Results] Tables 6 and 7 show the experimental results. The device configuration is the same as in the above and the experiments described above. As the heater 11, the substrate 15 is formed of aluminum and has a length of 250 mm, a width of 10 mm,
The thickness was 1 mm. The recording material conveyance speed is 200 mm /
In 5 seconds, the temperature of the fixing nip N was measured 5 seconds after the energization of the heater 11 was started. As a measuring method, the temperature was measured by sandwiching a thermocouple in the fixing nip portion N. Fixing film 63 used (FIG. 10)
Is a 50 μm polyimide layer as a film base layer 63 a and a 5 μm primer layer 63 b and a release layer 63 c
And a 10 μm PFA resin.
The fixing sleeve 13 used is a metal sleeve 13.
A primer layer 13b of 5 μm and a PFA resin as a release layer 13c of 10 μm were dipped on cylindrical aluminum and SUS having a thickness of 50 μm as a and a release layer 13c.
It is formed in a cylindrical shape with an outer diameter of 30.13 mm.

[0133]

[Table 6]

As described above, the higher the thermal conductivity of the fixing film 63 or the base material of the fixing sleeve 13 interposed between the heater 11 and the fixing nip N, the faster the temperature of the fixing nip N can be increased. Therefore, with the proposed configuration using the metal sleeve 13a, a fixing device that can easily cope with an increase in the speed of the image forming apparatus can be configured.

When aluminum was used as the metal sleeve 13a with the same configuration, the effect of heat capacity was confirmed by varying the thickness of aluminum. Similarly, a 5 μm-thick primer layer 13 b and a release layer 1
A 10 μm PFA resin as 3c was applied. Table 7 shows the temperature of the fixing nip portion N after 5 seconds from the start of energization to the energization heating layer 17.

[0136]

[Table 7]

From the above results, in order to prevent a decrease in the rate of temperature rise of the fixing nip due to an increase in heat capacity, the fixing sleeve 1
The thickness of the metal sleeve 13a which is the base material of No. 3 is 2
It is desirable to form it with a thickness of not more than 00 μm, preferably not more than 150 μm. The thickness that satisfies the mechanical strength and can withstand the life is preferably 30 μm or more.

[Experimental results on] Table 8 shows the experimental results for the following. The device configuration is the same as that of the above-described experiment. As the heater 11, the high thermal conductive substrate 15 was formed of aluminum, and the length was 250 mm, the width was 10 mm, and the thickness was 1 mm. Recording material transport speed is 2
The recording material P carrying the unfixed toner image was inserted into the fixing nip N 10 seconds after the power supply to the heater 11 was started at 10 mm / sec, and the fixing performance was confirmed. As the metal sleeve 13a of the fixing sleeve 13, as described above, an aluminum sleeve having an inner diameter of 30 mm was used as a base material. Further, one million A4 cut sheets as the recording material P were continuously conveyed, and the durability performance was confirmed. As a result of varying the radius of curvature r of the surface (curved outer surface) on the fixing nip portion N side of the arcuate cross section of the aluminum substrate as the high thermal conductive substrate 15 of the heater 11, the fixing performance and the durability performance are as shown in Table 8. The result was.

[0139]

[Table 8]

As described above, the radius of curvature r of the high thermal conductive substrate 15 having the arcuate cross section of the heater 11 on the fixing nip portion N side is obtained.
Is smaller than the radius r 'of the inner surface of the fixing sleeve 13 by providing a relationship of 0.5r'≤r≤3r', preferably a relationship of 0.8r'≤r≤2.4r '. 13 can be prevented from being fatigued, the life of the fixing sleeve 13 can be extended, and the heat from the heater 11 can be transferred to the fixing sleeve 1.
3, and the fixing performance is also sufficient.

[Results of Experiment] Tables 9 and 10 show the results of the experiment. The apparatus configuration is the same as that of the above-described experiment. As the heater 11, a high heat conductive substrate 15 is formed of aluminum, and has a length of 250 mm and a width of 10 m.
m, the thickness of the portion corresponding to the central portion within the fixing nip width is 1
mm. Recording material transport speed is 200mm / sec
10 seconds after the power supply to the heater 11 was started, the recording material P carrying the unfixed toner image was inserted into the fixing nip N, and the fixing performance was confirmed.

The high thermal conductive substrate 15 has a thickness distribution within the width of the fixing nip portion N. The central portion within the width of the fixing nip portion is thickest, and the central portion within the width of the fixing nip portion extends from the fixing nip portion width. It formed so that it may become symmetrically thinner in the upper and lower directions. As a method for confirming the fixing performance, the temperature of the heater 11 at which sufficient fixing performance was obtained was measured. In addition, image problems such as high-temperature offset and tailing at that time were also confirmed. As an evaluation method, the thickness of the high thermal conductive substrate 15 of the heater 11 corresponding to the central portion within the width of the fixing nip portion is 1 mm, and the thickness in the width direction of the fixing nip portion is set within the fixing nip portion width. It was confirmed by increasing and decreasing in proportion to. That is, the thickness was changed proportionally from the center in the width of the fixing nip to the most upstream or the most downstream. The curved shape on the side of the fixing nip N of aluminum, which is the high thermal conductive substrate 15 having a bow-shaped cross section in the cross section of the heater 11, was set to have a constant radius of curvature r = 16 mm, so that unevenness in thickness was maintained on the side of the heat-generating resistor layer 17. The evaluation results are shown below.

1) Table 9: Thickness variation only on the upstream side The thickness d in the table indicates the thickness of the uppermost stream of the nip.

[0144]

[Table 9]

2) Table 10: Thickness variation only on the downstream side The thickness d in the table indicates the thickness at the most downstream side of the nip.

[0146]

[Table 10]

As described above, according to the experiment, when the thickness of the high thermal conductive substrate 15 of the heater 11 becomes thinner in the width direction of the fixing nip portion than in the central portion in the width of the fixing nip portion, the high temperature offset, the tailing, etc. It has been found that the problem described above tends to occur, and conversely, when the thickness increases, the heat capacity increases, and the fixing temperature increases.

As a result of the above examination, the thickness of the high thermal conductive substrate 15 in the width of the fixing nip is about 0.5 to 2 times, preferably 0.6 times the thickness of the central portion in the width of the fixing nip. It is desirable that the film be formed in a range of about 1.8 to 1.8 times.

As described above, in this embodiment, the heater 11 is
A heating heater 1 comprising an insulating layer 16 and a current-carrying resistance layer 17 formed on a curved inner surface side of a thin metal high heat conductive substrate 15 having at least a fixing nip portion curved in a bow shape.
By using No. 1 to heat the fixing nip portion N intensively, a heat fixing device excellent in quick start property is configured.

Further, since the high thermal conductive substrate 15 is disposed between the energizing heat generating resistive layer 17 of the heater 11 and the fixing sleeve 13 at a width approximately equal to or larger than the fixing nip width and is formed with a substantially uniform thickness. Since the temperature in the longitudinal direction and the transport direction can be made uniform, it is possible to prevent adverse effects such as uneven fixing, high-temperature offset, and tailing.

Further, by using the metal sleeve 13a as the base material as the fixing sleeve 13, it is possible to perform heat fixing with high thermal efficiency for further increasing the speed of the image forming apparatus.

Further, by using the heater 11 having an arcuate curve, the fixing sleeve 1 having the metal sleeve 13a as a base material is used.
Even in the case of No. 3, fatigue breakage due to bending does not occur, and stable heat fixing can be performed for a long period of time.

<Second Embodiment> A second embodiment will be described below.

In this embodiment, the heating heater 11 is provided with a heat-generating resistor layer 1 for suppressing heat loss between the current-generating resistor layer 17 and the metal substrate 15 which is a high thermal conductive substrate.
A heat conductive filler 16a (FIG. 5B) is mixed in the insulating layer 16 interposed between the substrate 7 and the substrate 15. Further, the wear resistance is improved by mixing an anti-wear agent filler 18a (FIG. 5B) into the sliding layer 18 formed on the curved outer surface on the fixing nip portion side of the substrate 15.

The rest of the device configuration is the same as that of the first embodiment, so that the description will not be repeated.

Heat conduction filler 16a mixed in insulating layer 16
Is BN, alumina, A having higher thermal conductivity than the insulating layer 16
1N, an insulating filler such as an insulating metal oxide. The shape of the filler 16a may be any shape of a scale, a needle, or a sphere. As the content, the insulating layer 16
There is no particular limitation as long as the film can be formed.

The sliding layer 18 rubs against the inner surface of the metal sleeve 13a which is the base material of the fixing sleeve 13.
It gradually wears out after long use. As means for reducing the amount of abrasion and achieving a long service life, the sliding layer 18 made of fluororesin or the like, or the substrate 15 and the sliding layer 18 may be used.
At least one of an anti-wear agent filler such as glass beads, glass flakes, glass particles, silicon carbide, mica, ceramic powder, etc., in one or both of the primer layers interposed therebetween in order to increase the adhesive force. More than one type of filler 18a is mixed.

Alternatively, the filler 18a may be wrapped or fused with a member of the sliding layer 18, for example, a fluororesin, to perform a microencapsulation process.

As described above, the wear rate of the sliding layer 18 is reduced,
Good slidability is obtained over a long period.

The following experiment was performed to confirm the above effects.

[0161]. Relationship between amount of filler 16a mixed into insulating layer 16 and fixing performance. Relationship Between the Amount of Filler 18a Mixed into Sliding Layer 18 and Durability and Fixing Performance First, the fixing performance was confirmed with the same configuration as the experiment described in the first embodiment. .

The conveying speed of the recording material P is 300 mm / s
The experiment was performed at two speeds of ec and 350 mm / sec. The time from when the image forming apparatus received the print signal to when the recording material P reached the fixing nip N was 5 seconds.

The fixing sleeve 13 was formed by applying a primer layer 13c to a 50 μm-thick cylindrical aluminum 13a by 4 μm and a PFA resin 13c by 10 μm dipping to form a cylindrical shape having an outer diameter of 30 mm.

Insulating layer 1 made of polyimide for heater 11
The high thermal conductive filler 16a mixed in No. 6 is a scale-like BN having a particle diameter of 1 μm.

Table 11 shows the results of the experiment. "Fixing property 1" in the table is when the conveying speed of the recording material P is 300 mm / sec, and "Fixing property 2" is when it is 350 mm / sec.

[0166]

[Table 11]

As described above, the filler 16a having good thermal conductivity is added to the insulating layer 16 interposed between the heat generating resistance layer 17 of the heater 11 and the substrate 15 in an amount of 5 wt% or more, preferably 10 wt% or more, so that the thermal efficiency is further increased. Therefore, it is possible to configure a heat fixing device having good fixing performance even when the speed of the image forming apparatus is increased.

[0168] The amount of the filler 16a to be added is as follows.
6 may be formed within a range where the withstand voltage can be maintained as long as it can be formed, and is preferably 80 wt% or less.

FIG. 12 shows the results of the experiment. The configuration of the experimental apparatus was the same as that described above, and the amount of the BN filler 16a mixed in the insulating layer 16 interposed between the energized heating resistor layer 17 and the substrate 15 was 50 wt%. The recording material conveyance speed of the image forming apparatus is 300 mm /
The sliding layer 18 has a length of 5 μm and a thickness of 0.1 mm.
Each content of 5 μm TiO ₂ needle filler 18a was added.

The durability was determined by the number of cut sheets conveyed when the sliding layer 18 was shaved by 3 μm when cut sheets as a recording material were continuously heated and fixed.

[0171]

[Table 12]

As described above, by adding the wear-resistant filler 18a to the sliding layer 18 formed on the substrate 15 of the heater 11, the number of durable sheets is improved. However, if the filler addition amount is excessively increased, the surface roughness becomes large, and the heat transfer to the fixing sleeve 13 is deteriorated, so that there is a problem that the fixing performance is reduced. Therefore, although different depending on the type, particle size and shape of the additive, it is possible to improve the durability without deteriorating the fixing performance by adding the optimum amount of filler.

As described above, in the present embodiment, the thermal efficiency can be further increased by adding the heat conductive filler 16a to the insulating layer 16 interposed between the energized heat generating resistive layer 17 of the heater 11 and the substrate 15, so that image formation can be achieved. Fixing performance can be maintained for further speeding up of the apparatus.

Further, by adding a wear-resistant filler 18 a to the sliding layer 18 formed on the fixing nip portion N side of the substrate 15 of the heater 11, the sliding layer 18 is prevented from sliding against the fixing sleeve 13. The amount of wear can be reduced, and the life of the heat fixing device can be maintained long.

<Third Embodiment> (FIG. 8) A third embodiment will be described below.

In this embodiment, as shown in FIG. 8, the heat generated by the current-generating resistance layer 17 of the heater 11 can be efficiently supplied to the fixing nip N side of the heating heater 11. The heat insulating layer 19 is provided on the side opposite to the fixing nip N side.

The rest of the device construction is the same as in the first or second embodiment, and will not be described again.

The heat insulating layer 19 includes a polyimide layer, a glass layer,
Ceramic paint, fluororesin layer, silicon sponge layer,
It can be formed of an air layer or the like.

In the case where the heat insulating layer 19 is formed of an air layer, the protection layer (not shown) formed on the current-carrying resistance layer 17 or the current-carrying resistance layer in a part of the longitudinal direction is formed as a part of the stay holder 12. It may be configured to support with.

In particular, the thermal conductivity κ of the heat insulating layer 19 depends on the insulating layer 1 interposed between the heat-generating resistance layer 17 and the metal substrate 15.
6 and κ <κ ′.

As a result, the amount of heat generated by energizing the energizing heat generating resistive layer 17 selectively flows to the fixing nip N side. As a result, heat generated in the current-carrying resistance layer 17 can be efficiently transferred to the fixing nip N, so that quick start performance is improved, and even when the image forming apparatus is operated at a higher speed, the temperature of the fixing nip N can be easily increased. Can be heated.

In order to confirm the above effects, the stay holder 12 on the side opposite to the fixing nip portion N of the energized heating resistor layer 17 was checked.
The temperature of the fixing nip portion N was measured by interposing a heat insulating layer member having various thermal conductivities therebetween.

The heat insulating layer 19 has the same length of 260 mm, width 15 mm and thickness 3 mm so as to completely cover the current-carrying resistance layer 17 of the heater 11, and is made of mica, glass cotton, polyimide, air layer. And

The configuration of the apparatus used for the evaluation is the same as that of the experiment shown in the first embodiment. The conveyance speed of the recording material P is fixed at 300 mm / sec. 3 seconds after, the temperature of the fixing nip N was measured.

The fixing sleeve 13 is composed of a cylindrical aluminum 13a having a thickness of 50 μm, a primer layer 13b having a thickness of 4 μm, and a PF
A resin 13c having a cylindrical shape with an outer diameter of 30 mm applied by dipping with 10 μm was used.

As shown in the second embodiment, the heater 11 has the current-generating resistance layer 17 and the aluminum substrate 1 as shown in FIG.
5 was added to a polyimide layer, which is an insulating layer 16 interposed between the layers 5, to which 50 wt% of a scale-like BN filler 16a having a particle size of 1 μm was added.

Table 13 shows the results of the experiment.

[0188]

[Table 13]

From the above results, it can be seen that disposing the heat insulating layer 19 on the side opposite to the fixing nip portion N of the heater 11 of the heater 11 has the effect of increasing the temperature rising speed of the fixing nip portion N. I was separated.

The insulating layer 16, which is interposed between the current-generating resistance layer 17 of the heater 11 and the metal substrate 15,
Thermal conductivity κ 'of polyimide layer containing 0 wt% BN filler
In contrast, the thermal conductivity κ of the heat insulating layer 19 was varied, and a rise in the temperature of the fixing nip N was similarly confirmed. The thermal conductivity κ of the heat insulating layer 19 was confirmed by varying the thermal conductivity by varying the amount of the heat conductive filler B19N in the polyimide layer of the above experiment as the heat insulating layer 19. Table 14 shows the results.

[0191]

[Table 14]

From the above results, it is desirable that the thermal conductivity of the heat insulating layer 19 be lower than the thermal conductivity of the insulating layer 16 interposed between the current-carrying resistance layer 17 of the heater 11 and the metal substrate 15. .

As described above, in this embodiment, the amount of heat generated by the current-carrying resistance layer 17 of the heater 11 is efficiently supplied to the fixing nip N, whereby the rate of temperature rise of the fixing nip N can be increased. .

Therefore, even if the speed of the image forming apparatus is increased, the quick start property can be further improved without taking measures such as increasing the power supplied to the heater 11.

Here, the image heating apparatus of the present invention is not only a heating and fixing apparatus of each embodiment, but also an image heating apparatus for heating a recording material carrying an image to improve the surface properties (such as gloss).
It can be widely used as an assumed image heating device.

[0196]

As described above, according to the present invention, quick start and short first print time are satisfied, and even if the image forming apparatus is operated at high speed, the performance can be easily reduced without impairing these performances. An image heating heater, an image heating apparatus, and an image forming apparatus including the image heating apparatus capable of ensuring uniform fixing performance of a toner image on a recording material and achieving long-life heat fixing. Can be provided.

[Brief description of the drawings]

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

FIG. 2 is a schematic cross-sectional view of a heat fixing device.

FIG. 3 is an enlarged cross-sectional model diagram of a portion near a fixing nip portion.

FIG. 4 is a schematic diagram of a layer configuration of a fixing sleeve.

FIG. 5 (a) is a plan view of the back side of the heater,
(B) is a cross-sectional enlarged model diagram of the heater.

FIG. 6 is a plan view of the back side of another example of the heater.

FIG. 7 is a graph showing surface temperature characteristics along a heater length of a heater having a heater substrate of aluminum and a heater having a heater substrate of glass.

FIG. 8 is an enlarged cross-sectional model view of a portion near a fixing nip portion of a heat fixing device according to a third embodiment.

[Explanation of symbols]

10 ··· Fixing member (heating member), 11 ·· Heating heater, 12 ·· Heat insulation stay holder, 13 ··· Fixing sleeve, 14 ··· Temperature detecting element, 15 ··· Metal substrate (heater substrate, high thermal conductivity) Board), 16..insulating layer, 17 ..
Electric heating resistor layer, 18 ... sliding layer (lubricating layer), 19 ...
Insulation layer

 ────────────────────────────────────────────────── ─── Continued on front page (72) Inventor Masahiro Goto 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2H033 AA23 AA31 BA26 BE03 3K034 AA02 AA03 AA12 AA15 AA20 AA34 AA35 BA06 BA08 BA14 BB02 BB14 BC22 BC29 CA02 CA14 CA32 DA05 DA08 FA13 FA17 GA02 GA04 HA01 HA10 3K058 AA02 AA86 BA18 CA12 CA61 CE02 CE03 CE04 CE13 CE19 DA04 GA03 GA06 3K092 PP18 QA06 QB02 QB04 QB17 QB26 QB31 RFB09 RFBQ31 RF SS14 TT35 UA06 UA17 VV16 VV22

Claims (22)

[Claims] 1. An arc-shaped metal member having at least a portion curved in a cross section as a base material, and an insulating layer and a current-carrying resistance layer are sequentially laminated in an arcuate shape on the inner side of the curved surface of the metal member. An image heating heater, comprising: 2. The image heating heater according to claim 1, wherein a filler made of a member having a higher thermal conductivity than the insulating layer is added to the insulating layer. 3. An image heating heater according to claim 2, wherein said insulating layer is made of polyimide, and said filler is at least one of BN, AlN, alumina and an insulating metal oxide. 4. A sliding layer made of a fluororesin, a dry film lubricant containing at least one solid lubricant of molybdenum disulfide and graphite, or a glass on the curved outer surface side of the metal member. 4. An image heating heater according to claim 1, wherein a lubricating layer is formed. 5. The image heating heater according to claim 4, wherein a filler harder than the sliding layer is added to the sliding layer. 6. The heater according to claim 5, wherein the filler is at least one of glass beads, glass flakes, glass particles, silicon carbide, mica, and ceramic powder. 7. The image heating heater according to claim 1, wherein a heat insulating layer is provided on an inner side of the curved surface of the heat generating resistance layer. 8. The image heating heater according to claim 7, wherein the thermal conductivity of the heat insulating layer is lower than the thermal conductivity of the insulating layer. 9. An image heating apparatus for heating an image on a recording material by nipping and transporting the recording material at a heating nip formed by mutual pressure contact between a heating member having an image heating heater and a pressing member, The image heating heater has a bow-shaped metal member at least partially curved in a cross section as a base material, and an insulating layer and a current-carrying resistance layer are sequentially laminated in a bow shape on the curved inner surface side of the metal member. An image heating device, comprising: 10. An image heating apparatus according to claim 9, wherein a filler made of a member having higher thermal conductivity than said insulating layer is added to said insulating layer. 11. The insulating layer is made of polyimide, and the filler is at least one of BN, AlN, alumina, and an insulating metal oxide.
An image heating device according to claim 1. 12. A dry film lubricant containing at least one solid lubricant of fluorine resin, molybdenum disulfide, and graphite on the curved outer surface side of the metal member.
12. The image heating apparatus according to claim 9, wherein a sliding layer (lubricating layer) made of glass is formed. 13. An image heating apparatus according to claim 12, wherein a filler harder than said sliding layer is added to said sliding layer. 14. An image heating apparatus according to claim 13, wherein said filler is at least one of glass beads, glass flakes, glass particles, silicon carbide, mica, and ceramic powder. 15. An image heating apparatus according to claim 9, wherein a heat insulating layer is provided on the inner side of the curved surface of said heat generating resistance layer. 16. The image heating apparatus according to claim 15, wherein the thermal conductivity of the heat insulating layer is lower than the thermal conductivity of the insulating layer. 17. The heating member has a rotatable cylindrical member whose base is a metal sleeve forming a heating nip portion by pressing against the pressing member, and the inner surface of the cylindrical member is the same as that of the heating member. 17. The image heating apparatus according to claim 9, wherein the image heating apparatus rotates while rubbing against the curved outer surface of the image heating heater. 18. The image heating apparatus according to claim 17, wherein a metal sleeve as a base material of said cylindrical member is formed in a thickness range of 30 μm to 200 μm. 19. The curvature radius r of the curved outer surface of the image heating heater is the same as the curvature radius r 'of the inner surface of the cylindrical member.
19. The image heating apparatus according to claim 17, wherein a relationship of 5r'≤r≤3r 'is satisfied. 20. The thickness of the metal member portion of the image heating heater corresponding to at least the heating nip portion is set to be equal to the thickness of the metal member portion corresponding to the central portion in the width direction of the heating nip portion.
20. The image heating apparatus according to claim 9, wherein the thickness is in a range of 5 times to 2 times. 21. An image heating apparatus according to claim 9, wherein said apparatus is a heat fixing apparatus for fixing an unfixed image as a permanent image on a recording material. 22. An image forming apparatus comprising the image heating device according to claim 9.