JP3382477B2 - Heating equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to aluminum nitride.
Substrate and the resistance generated on one surface of this substrate.
A heating element having a heating layer and a resistance heating layer of the heating element are provided.
The film that moves while making contact with the opposite surface
And heat the material to be heated with the heat from the heating element through the film.
Heating device .

[0002]

2. Description of the Related Art For example, in an image forming apparatus which employs an image forming process such as an electrophotographic method or an electrostatic recording method, an indirect method (transfer method) is used on a recording material such as transfer paper, photosensitive paper or electrostatic recording paper. ) Or a heating device (heat fixing device) that heats and fixes a heat fixing property developer image (unfixed toner image) formed and carried by a direct method on a recording material as a permanently fixed image. The heat roller type device is often used.

This is a pressure contact nip portion (fixing nip portion) between a heating roller (fixing roller) heated and maintained at a predetermined heating temperature by a built-in heat source such as a halogen heater and an elastic pressure roller pressed against the heating roller. The recording material is introduced and nipped and conveyed to heat and fix the unfixed image on the surface of the recording material by the heat of the heating roller.

However, since the heat capacity of the heating roller is large, the heating device of the heating roller type requires a considerable waiting time from supplying the electric power to the built-in heat source to raising the heating roller to a predetermined heating temperature from a cold state. The temperature of the heating roller does not have a quick start property.After the temperature of the heating roller has been raised to a specified value, the temperature of the heating roller is kept at a specified temperature by supplying power to the built-in heat source even when the device is in standby to keep it ready for use. However, there is a problem that the power consumption is large because the control (preheating control) for maintaining the power consumption is required.

Recently, a film heating type heating device has been proposed and put into practical use (Japanese Patent Laid-Open No. 63-3131).
82 / JP-A-1-263679 / JP-A-2
No. 157878 / JP-A-4-44075-440
No. 83 / Japanese Patent Laid-Open No. 4-204980-204984).

In this film heating type heating device, a material to be heated is brought into close contact with a fixedly supported heating body through a heat-resistant thin film material, and the film material is slid on the heating body to move the heating body. It is of a system and configuration in which heat is applied to a material to be heated through a film material, and can be utilized as an apparatus for heat-fixing an unfixed toner image as a permanently fixed image on the surface of a recording material carrying the image. Further, for example, it can be widely used as an apparatus for heating a recording material carrying an image to modify the surface properties such as gloss, a hypothetical adhesion processing apparatus, and an apparatus for heating a sheet-shaped heating material.

Such a film heating type heating device has a low heat capacity, such as a heating body, which can quickly raise the temperature.
An insulating base material and a so-called ceramic heater, which is provided on one surface side of the base material and has a basic resistance heating layer that generates heat when energized, is used in a short time because a thin film can be used as a film material. Since the temperature of the heating element rises, it is not necessary to supply power to the heating element during standby, and even if the recording material as the heating material is passed immediately, the heating is performed until the recording material reaches the fixing portion. The temperature inside the machine such as an image forming apparatus can be raised, which can sufficiently warm the body to a predetermined temperature, shorten the wait time (quick start property: operate on demand), and save power. It is advantageous because it has the advantage of being able to lower it.

FIG. 14 is a cross-sectional model view of a main part of a film heating type heating device (heating fixing device), FIG. 8A is a rear model view of the heating element with the middle part omitted and partially cut away. FIG.

Reference numeral 41 designates a heating body as a heating member (hereinafter referred to as a heater), 42 a stay holder (heater support body) in which the heater 41 is fixedly supported on the lower surface, and 43 a heat-resistant material.
Thin film material (hereinafter referred to as fixing film), 50
Is an elastic pressure roller.

The fixing film 4 includes a heater 41 fixedly supported on the lower surface of the stay holder 42 and an elastic pressure roller 50.
A nip portion (hereinafter referred to as a fixing nip portion) N having a predetermined width is formed by sandwiching 3 and pressing them against each other with a predetermined pressing force against the elasticity of the elastic pressure roller 50.

A ceramic heater is generally used as the heater 41, and is heated / controlled to a predetermined temperature by being energized.
The structure of the heater 41 will be described later.

The fixing film 43 is a cylindrical member, an endless belt member, or a roll-wound endless web member, and has a driving means (not shown) or an elastic pressure roller 50.
The inner surface of the film in the fixing nip portion N is conveyed and moved in the direction of the arrow while sliding in close contact with the lower surface of the heater 41 by the rotational force of. The stay holder 42 is, for example, a heat-resistant plastic member, which holds the heater 41 as described above and also serves as a conveyance guide for the fixing film 43.

In a state where the fixing film 43 is conveyed and moved, and the heater 41 is heated and temperature-controlled to a predetermined temperature, a material to be heated is provided between the fixing film 43 in the fixing nip portion N and the elastic pressure roller 50. When the recording material P on which the unfixed toner image t is formed and carried is introduced with the image bearing surface side being the fixing film side, the recording material P comes into close contact with the outer surface of the fixing film 43 at the fixing nip portion N and the fixing is performed. The fixing nip portion N is nipped and conveyed together with the film 43.
In the fixing nip portion N, the recording material P / toner image t is heated by the heater 41 via the fixing film 43, and the toner image t is heat-fixed on the recording material P surface. The recording material portion passing through the fixing nip portion N is the fixing film 43.
Is conveyed separately from the outer surface of the. ta represents a toner image that has been heat-fixed.

The fixing film 43 has a considerably small thickness of 20 to 70 μm in order to efficiently apply the heat of the heater 41 to the recording material P as a material to be heated in the fixing nip portion N. The fixing film 43 has a three-layer structure including a film base layer, a primer layer, and a releasing layer. The film base layer side is the heater 41 side, and the releasing layer is the pressure roller 50 side. The film base layer is made of polyimide, polyamideimide, PEEK or the like having higher insulation than the glass protective layer 41d of the heater 41 described later, and has heat resistance and high elasticity. Further, the fixing film 43 is formed by the film base layer.
Maintains mechanical strength such as overall tear strength. The primer layer is formed as a thin layer having a thickness of about 2 to 6 μm.
The releasable layer is a toner offset preventing layer for the fixing film 43, and is formed by coating a fluororesin such as PFA / PTFE / FEP to a thickness of about 10 μm.

A ceramic heater is generally used as the heater 41.
used. For example, electrical insulation and good heat transfer of alumina, etc.
Conductive, low heat capacity ceramic substrate (insulating substrate, heater substrate
The surface side of the plate 41a (on the side facing the fixing film 43)
Surface, heater surface side) along the length of the substratepalladium
(Ag / Pd) / Ta_TwoResistance heating layer such as N
The protective layer 41b is formed by screen printing or the like.
It 41c and 41c are provided on both ends of the resistance heating layer 41b.
It is a power supply electrode part that is made conductive respectively, silver paste etc.
Formed on the substrate surface side by screen printing using the conductive material of
It is equipped. Resistance of ceramic substrate 41a
The surface on which the heat layer is formed is covered with a glass protective layer 41d to form a resistance heating layer.
Wear and damage due to the sliding contact of the fixing film 43 of 41b
Is prevented. The back side of the ceramic substrate 41a (constant
The surface on the side opposite to the surface facing the adhesive film 43,
Example of temperature detection member (temperature detection means) 41e on the rear side
For example, a thermistor is placed. 41f ・ 41f, 41
g · 41g is a wiring part (D) for the thermistor 41e.
C energizing part) and electrode part (DC electrode part), ceramic
A conductive material such as silver paste is used on the back side of the substrate 41a to remove the gap.
It is formed and equipped by clean printing or the like.

The ceramic heater 41 has a resistance heating layer 4
1b from the power feeding portion (not shown) to the power feeding electrode portion 41c.
When electricity is supplied through 41c, the resistance heating layer 41b generates heat and the entire heater including the ceramic substrate 41a and the glass protection layer 41d rapidly rises in temperature. This heater 4
Temperature detection member 41e installed on the back of the heater
The detected temperature information is detected by the wiring parts (DC energizing parts) 41f and 41f and the electrode parts (DC electrode parts) 41g and 4
It is fed back via 1g to an energization control unit (temperature control unit) not shown. The energization control unit controls power supply from the power supply unit to the resistance heating layer 41b so that the heater temperature detected by the temperature detection member 41e is maintained at a predetermined substantially constant temperature (fixing temperature). That is, the heater 41 is heated / controlled to a predetermined fixing temperature.

In such a film heating type heating device, a so-called ceramic heater 41 having a low heat capacity capable of rapid temperature rise can be used as a heating body, and a thin film having a low heat capacity can also be used as the film material 43. The pressure roller 50 having an elastic layer for high rigidity of 41 is flattened at the pressure contact portion to form the fixing nip portion N having a predetermined width, following the flat lower surface of the heater 41 against which the pressure roller 50 is pressed. By heating only the fixing nip portion N, quick start and power saving heat fixing are realized as compared with other heating devices such as a heat roller type.

[0018]

However, in the conventional film heating type heating device as described above,
． The resistance heating layer 4 of the heater 41 in the fixing nip portion N
1b and the fixing film 43 have a glass protective layer 41d having a large thermal resistance, and the thermistor 41e as a temperature detecting member on the rear surface of the high thermal conductive ceramic substrate 41a controls the temperature. The amount of leak is large, and the heat leak reduces the heating efficiency of the fixing nip portion N side, that is, the heating efficiency of the heated material P.
． Further, since the fixing film 43 and the material to be heated P are heated through the glass protective layer 41d having poor heat conduction, the fixing nip portion N is heated substantially only by the width of the resistance heating layer 41b, which is disadvantageous for heat fixing. There was a problem. ．
As the structure of the heater 41, a resistance heating layer 41b, a power supply electrode 41c, a glass protective layer 41d and the like are provided on the front surface side of a ceramic substrate 41a which is a heater substrate, and a thermistor 41e, a wiring portion 41f and an electrode portion 41g are provided on the back surface side. However, there is a problem in that the manufacturing process is complicated.

Therefore, the present invention has an insulating base material and a resistance heating layer which is provided on one surface side of the base material and generates heat when energized, as a basic constituent body, and is a fixed and supported heating body for heating a material to be heated. (heaters), with the heating equipment with a the heating body,
To solve the above problems (1), that is, to prevent heat leak to the back side of the heating element to enable efficient heating of the material to be heated, and to cover the entire width of the material to be heated of the heating element. Enables heating of the heating material, enables temperature control with less temperature ripple, prevents film inner surface abrasion in film heating type heating devices, simplifies the heating element structure, and simplifies the manufacturing process. For the purpose of

[0020]

The present invention is a heating device characterized by the following constitutions.

(1) Aluminum nitride substrate and this substrate
Heating with resistance heating layer formed on one side of plate
The body and the surface opposite to the surface of the heating element on which the resistance heating layer is provided.
And a film that moves while in contact with the film.
The heating device that heats the material to be heated with the heat from the heated body
And the aluminum nitride layer is formed on the resistance heating layer of the heating element.
A temperature detection member is installed via a high thermal conductivity insulating member made of um.
A heating device characterized by being removed.

(2) The high thermal conductive insulating member has high thermal conductivity
Contacting the resistance heating layer via insulating grease
The heating device according to claim 1, wherein:

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

<Operation> a. In the present invention, the heating body has an insulating base material and a resistance heating layer which is provided on one surface side of the base material and generates heat by energization as a basic constituent body, and is provided on the same side as the side where the resistance heating layer is provided. The surface of the insulating base material having the temperature detecting member, and the surface of the insulating base material having the resistance heating layer and the temperature detecting member (on the rear side of the heating element)
Since it is a back-heating type heating body whose surface (heater surface side) opposite to that is a surface for applying thermal energy to the material to be heated, the material to be heated is the insulating body of the heating body which is the surface side of the heating body. Direct contact with a single surface of the material, without interposing other member layers that have thermal resistance, or through a heat-resistant thin film of low heat capacity in the case of a film heating type heating device. Contacted and heated. Therefore, the amount of heat leak to the back side of the heating element is small, and the material to be heated can be efficiently heated.

B. By setting the insulating base material of the heating element to the aluminum nitride substrate which is a high thermal conductivity member, the heat generation of the resistance heating layer causes the whole of the aluminum nitride substrate to be heated and heated rapidly and substantially without temperature unevenness. As a result, it is possible to heat the material to be heated over the entire width of the material to be heated portion of the heating element, and to perform efficient heating of the material to be heated with less heat leakage to the back side of the heating element and small temperature ripple, and the substrate width. It is possible to reduce the size and to heat and fix the heated material in a small space.

C. By providing a resistance heating layer, a temperature detection member, etc. on the back side of the insulating base of the heating body (back side of the heating body), the structure of the heating body can be simplified by providing on the back side of the insulating base of the heating body (back side of the heating body). The manufacturing process can be simplified.

[0046]

[0047]

D. By providing a temperature detecting member in contact with the resistance heating layer through a high heat conducting member made of aluminum nitride, and having a high heat conductive grease between the resistance heating layer and the high heat conducting member. Not only is it possible to efficiently heat the material to be heated with a small temperature ripple, but it is also possible to prevent contact failure of the high thermal conductive member and to perform stable temperature control.

[0049]

[0050]

[0051]

[0052]

BEST MODE FOR CARRYING OUT THE INVENTION Reference Example 1 (FIGS. 1 to 5) (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 example is a laser beam printer using a transfer type electrophotographic process.

Reference numeral 1 is a photosensitive drum as an image carrier,
A photosensitive material such as OPC (organic photoconductor), amorphous Se, or amorphous Si is formed on a cylindrical substrate such as aluminum or nickel.

The photosensitive drum 1 is rotationally driven in the clockwise direction indicated by an arrow at a predetermined peripheral speed (process speed), and in the course of the rotation, the charging roller 2 as a charging means uniformly charges the photosensitive drum 1 to a predetermined polarity and potential. .

Next, modulation control (corresponding to the time-series electric digital pixel signal of the target image information output from the laser scanning exposure device (laser beam scanner) 3 is applied to the charged surface of the rotary photosensitive drum 1 ( ON / OFF controlled) laser beam L is used for scanning exposure,
An electrostatic latent image corresponding to desired image information is formed on the surface of the rotating photosensitive drum.

The electrostatic latent image formed on the surface of the rotating photosensitive drum is developed (visualized) as a toner image by the developing device 4.
As a developing method, a jumping developing method, a two-component developing method, an FEED developing method, or the like is used, and image exposure and reversal developing are often used in combination.

On the other hand, as a recording material, a nip portion (transfer nip portion) n between the rotary photosensitive drum 1 and a transfer roller 5 as a transfer means abutted on the rotary photosensitive drum 1 is fed from a paper feed mechanism portion (not shown). The transfer material P is fed at a predetermined control timing,
The transfer nip portion n, that is, the photosensitive drum 1 and the transfer roller 5 are nipped and conveyed at a constant pressure, and the toner images on the surface of the rotating photosensitive drum 1 are sequentially transferred to the surface of the transfer material P.

The transfer material P, to which the toner image has been transferred at the transfer nip portion n, is separated from the surface of the photosensitive drum 1 and is conveyed to the heat fixing device 6 as a heating device to receive the heat fixing of the toner image, and is discharged and conveyed. It The heat fixing device 6 will be described in detail in the following item (2).

The surface of the photosensitive drum 1 after the transfer of the toner image onto the transfer material P is cleaned by the cleaning device 7 which removes residual toner remaining after transfer and other adhering contaminants.
It is repeatedly used for image formation.

(2) Heat fixing device 6 a) Overall schematic configuration of the device FIG. 2 shows the heat fixing device 6 of this embodiment.
2 is a schematic configuration model diagram of FIG. The heat fixing device 6 of this example is a pressure roller driving type / tensionless type film heating type heating device disclosed in Japanese Patent Application Laid-Open No. 4-44075 to 44083.

Reference numeral 10 is a heating member / fixing film assembly as a fixing member, and 20 is an elastic pressure roller as a pressure member.

The heating member / fixing film assembly 10 as a fixing member is a stay holder (heater support member) 12 having a substantially semicircular cross section and a heating member fixedly supported on the lower surface of the stay holder 12 along the length of the holder. Body (hereinafter,
A heater 11), a cylindrical fixing film 13 loosely fitted to a stay holder 12 fixedly supporting the heater 11, and the like. Heater 1
The structure of 1 is described in detail in the following section b).

Then, the heater 11 of the heating member / fixing film assembly 10 as a fixing member and the elastic pressure roller 20 as a pressure member are sandwiched by the fixing film 13 to resist the elasticity of the elastic pressure roller 20 to a predetermined value. The nip portion (hereinafter, referred to as a fixing nip portion) N having a predetermined width is formed by pressing with a pressing force of.

The elastic pressure roller 20 as a pressure member is
A cored bar 21 and an elastic layer 22 formed by foaming a heat resistant rubber such as silicone rubber or fluororubber or silicone rubber on the outside thereof. PFA / PT on the outside of the elastic layer 22
The release layer 23 such as FE / FEP may be formed. In this example, both ends of the elastic pressure roller 20 are sufficiently urged by a pressure means (not shown) toward the heating member / fixing film assembly 10 as a fixing member so that the fixing film 13 is sandwiched between the heaters. By making contact with 11 by pressure, a fixing nip portion N necessary for heat fixing is formed.

The elastic pressure roller 20 is rotationally driven in the counterclockwise direction indicated by the arrow by the drive means M (pressure roller drive type). Then, the rotational force acts on the cylindrical fixing film 13 due to the contact frictional force between the roller 20 and the outer surface of the fixing film 13 in the fixing nip portion N due to the rotational driving of the elastic pressure roller 20, and the fixing film 13 stays. At the fixing nip portion N, the inner surface of the film is rotated in the clockwise direction of the arrow while sliding on the outer surface of the holder 12 in close contact with the downward surface of the heater 11.

Then, the fixing film 13 is rotated by the rotation of the elastic pressure roller 20, and when the heater 11 is heated to a predetermined temperature by energizing the heater 11, the fixing film 13 and the fixing film 13 in the fixing nip portion N are elastically heated. The transfer material P as a recording material carrying the unfixed toner image t is introduced between the pressure roller 20 and the toner image carrying surface is in close contact with the outer surface of the fixing film 13 and the fixing nip portion N together with the fixing film 13. And the heat of the heater 11 is applied to the transfer material P via the fixing film 13, and the unfixed toner image t is heated and fixed on the surface of the transfer material P. The transfer material P that has passed through the fixing nip portion N is curvature-separated from the surface of the fixing film 13 and discharged and conveyed. ta represents a toner image that has been heat-fixed.

The stay holder 12 functions as a support for the heater 11 and also serves to pressurize the fixing nip portion N and to stabilize the rotational conveyance of the cylindrical fixing film 13. Further, the stay holder 12 is a heat insulating member for preventing heat radiation of the heater 11 to the side opposite to the fixing nip portion N side (heat leak to the back side of the heater), and includes liquid crystal polymer, phenol resin, PPS, PEEK. And the like.

The inner surface of the fixing film 13 rotates while sliding on the lower surface of the heater 11 in the fixing nip portion N and on the outer surface of the stay holder 12 in the vicinity of the fixing nip portion N. In order to smoothly rotate the fixing film 13 with a low torque, it is necessary to suppress the frictional resistance between the heater 11 and the stay holder 12 and the fixing film 13 to be small. Therefore, a small amount of lubricant such as heat resistant grease is interposed between the heater 11 and the stay holder 12 and the fixing film 13. This allows the fixing film to rotate smoothly.

The fixing film 13 is a member having a small heat capacity, and is 100 μm in order to enable quick start.
Polyimide, polyamide imide, PEEK, PES, PPS, PFA, which have heat resistance and thermoplasticity with the following thickness
It is a film such as PTFE / FEP. Further, a film having sufficient strength and excellent durability to form a heat fixing device having a long life is required to have a thickness of 20 μm or more. Therefore, the thickness of the fixing film 13 is 20 μm.
The optimum value is m or more and 100 μm or less. Further, in order to prevent offset and ensure the separability of the recording material, the surface layer of the fixing film is coated with a heat-resistant resin having good releasability such as PFA / PTFE / FEP / silicone resin, either mixed or alone. .

B) Heater 11 FIG. 3 is an enlarged cross-sectional model view of an essential part of the heat fixing device 6, FIG.
(A) is a surface model diagram with the middle part of the heater 11 omitted,
(B) is a rear model view with the middle part omitted, and (c) is a side view model with the middle part omitted.

The heater 11 in this example is a ceramic heater, and 1) the insulating base material (heater substrate) 11a of the heater 11 is an aluminum nitride (AlN) substrate. 2) the fixing film 1 of the aluminum nitride substrate 11a.
3 is the front surface side and the opposite surface is the back surface side, the resistance heating layer 1 is provided on the back surface side of the substrate 11a.
1B and the temperature detection member 11e are arranged to form a backside heating type heater.

The aluminum nitride substrate 11a as the heater substrate of the heater 11 used in this example has a thickness of 0.5 mm, a length of 270 mm, a width of 11 mm, and a thermal conductivity of 220 W / m · °.
It is a high thermal conductivity member of K.

In this example, this aluminum nitride substrate 11a is used.
As shown in FIG. 4B, two parallel resistance heating layers 11b and 11b are formed on the back side of the substrate at intervals along the length of the substrate. The resistance heating layers 11b and 11b have a thickness of 1 by a screen printing method using an energization heating resistance material such as Ag / Pd (silver-palladium), RuO ₂ , Ta ₂ N.
It is formed by applying a thin strip-shaped pattern having a width of about 0 μm and a width of about 1 to 5 mm. This parallel two-row resistance heating layer 11b.1
One ends of 1b are electrically connected to each other by a conductive pattern portion 11d to be connected to each other. In addition, the power supply electrode portions 11c and 11c are electrically connected and provided on the other end side. The conductive pattern portion 11d and the feeding electrode portion 11c
11c can be formed and provided on the substrate surface by screen printing using a conductive material such as Ag paste / Ag / Pt (silver / platinum).

The temperature detecting member 11e is, for example, a thermistor, which is also provided on the back side of the substrate 11a between the two parallel resistance heating layers 11b and 11b.
And an insulation distance. 11f, 11f, 1
1g and 11g are a wiring part (DC energizing part) and an electrode part (DC electrode part) for the thermistor 11e.
A conductive material such as Ag paste / Ag / Pt is formed on the back side of 1a by screen printing or the like.

The heater 11 has a resistance heating layer 11b.1 from a power feeding unit (not shown) through power feeding electrode units 11c and 11c.
1b is energized to generate the resistance heating layer 1
1b11b heats up and the heater substrate 11a rapidly rises in temperature. The temperature of the heater substrate 11a is raised by the temperature detecting member 11e.
The detected temperature information is detected by the wiring part (DC energizing part) 11f · 11f and the electrode part (DC electrode part) 11g · 1.
It is fed back via 1g to an energization control unit (temperature control unit) not shown. The energization control unit controls the power supply from the power supply unit to the resistance heating layer 41b so that the heater temperature detected by the temperature detection member 41e is maintained at a predetermined substantially constant temperature (fixing temperature), for example, in the resistance heating layer 11b. Appropriately control the duty ratio and wave number of the applied voltage.
That is, the heater 11 is heated and temperature-controlled to a predetermined fixing temperature.

The front surface side of the heater 11 is a single surface of the heater substrate 11a, and the heater 11 is fixedly supported on the lower surface of the stay holder 12 by exposing the front surface side downward. The fixing film 13 is slidably moved in the fixing nip portion N in close contact with the heater surface, that is, a single surface of the heater substrate 11a.

In the case of this configuration, the fixing film 13 has the fixing surface at the heater nip portion N, that is, the heater substrate 11a.
The single surface is directly contacted and intimately slid to be heated without interposing another member layer having a thermal resistance, and is heated. Therefore, the amount of heat leak to the back side of the heater is small, and the heating efficiency of the fixing nip portion N side, that is, the heating efficiency of the heated material P is improved, and the fixing property is improved.

Further, since an aluminum nitride substrate, that is, a substrate having a high thermal conductivity is used as the heater substrate 11a, when the resistance heating layer 11b generates heat, the entire heater substrate 11a is rapidly heated / heated substantially without temperature unevenness. As a result, heat fixing is possible in the entire width area of the fixing nip portion N, and the fixing property is improved.

Further, since the resistance heating layer 11b, the power supply electrode 11c, the thermistor 11e, the wiring portion 11f, the electrode portion 11g, etc. of the heater 11 are all on the back side of the heater substrate 11a, the heater structure is simple and the manufacturing process is simplified. Can be converted.

For comparison, as shown in FIG. 5, the heater 11 has a resistance heating layer 11b on the surface side of the heater substrate 11a.
The resistance heating layer forming surface of the heater substrate 11a is covered with a glass protective layer 16 having a thickness of 50 μm, and a thermistor 11e as a temperature detecting member is arranged on the back side of the heater substrate 11a. I chose

In this conventional type heater 11A, the glass protective layer 16 having a large thermal resistance is provided between the resistance heating layer 11b on the heater surface side and the fixing film 13, so that the heat leak to the rear side of the heater is large and the temperature control is performed. When the control is performed, the heating efficiency on the fixing nip portion N side, that is, the heated material P
The heating efficiency of is reduced. Further, since the fixing nip portion N is heated via the glass protective layer 16 having poor heat conduction,
The fixing nip portion N is substantially heated only by the width of the resistance heating layer 11b, which is disadvantageous for heat fixing. Also, the heater substrate 1
The resistance heating layer 11b, the power supply electrode 41c, the glass protective layer 16, the thermistor 11e, and the both sides of the front side and the back side of 1b.
It is necessary to form and equip the wiring portion 11f, the electrode portion 11g, and the like by printing or the like, which complicates the manufacturing process.

On the other hand, in the case of the back surface heating type heater 11 in which the resistance heating layer 11b and the thermistor 11e are arranged on the back surface side of the high thermal conductive aluminum nitride substrate 11a as shown in FIGS. Since the fixing nip portion N is heated without passing through the glass protective layer 16 having a high heat resistance as described above, heat can be efficiently transmitted to the material P to be heated.
In this example, since the heater substrate 11a is made of aluminum nitride having a thickness of 0.5 mm and a thermal conductivity of 220 W / m · ° K, a glass protective layer having a thickness of 50 μm and a thermal conductivity of 1 W / m · ° K. The thermal resistance is 1/20 or less with respect to 16. Furthermore, since an aluminum nitride substrate, that is, a substrate having a high thermal conductivity is used as the heater substrate 11a, the entire heater substrate 11a is heated and heated quickly and substantially without temperature unevenness to heat the entire width region of the fixing nip portion N. Fixing is possible and fixing property is improved. Further, since the resistance heating layer 11b, the power supply electrode 11c, the thermistor 11e, the wiring portion 11f, the electrode portion 11g, etc. of the heater 11 are all on the back side of the heater substrate 11a, the heater structure is simplified and the manufacturing process can be simplified.

The heat fixing device using the conventional heater 11A shown in FIG. 5 and the heat fixing device using the rear surface heating type heater 11 shown in FIGS. . The results are shown in Table 1.

[0084]

[Table 1] As can be seen from Table 1, the back surface heating type heater 11 has better morning fixability than the conventional type heater 11A. At the time of fixing, 600 W was fully heated without temperature control in order to eliminate the difference in the temperature detected by the thermistor etc., and the paper was passed 6 seconds after the start of heating.

From the above results, by disposing the resistance heating layer 11b and the thermistor 11e as the temperature detecting member on the back surface of the ceramic substrate 11a, a simple heater structure can be obtained.
Efficient heat fixing is possible.

Reference Example 2 (FIG. 6) As shown in FIG. 6, the heater 11 of this example has a heater substrate 11a.
The resistance heating layer 11b on the back side of the
Like the conventional heater 41 described above, the heater 41 is formed and provided in a single structure, and a thermistor 11e as a temperature detecting member is also provided on the back side of the heater substrate 11a in the widthwise center O of the fixing nip portion N.
Is a rear surface heating type upstream thermistor heater having a configuration arranged upstream of the fixing nip portion N in the sheet passing direction a.
The heater substrate 11a is an aluminum nitride substrate.

The fixing film 13 is slidably moved in the fixing nip portion N in close contact with the heater surface, that is, a single surface of the heater substrate 11a.

By disposing the thermistor 11e as a temperature detecting member on the upstream side in the sheet passing direction a of the fixing nip portion N with respect to the center O in the width direction of the fixing nip portion N as in this example, the thermistor 11e is fixed to the fixing nip portion N. It is considered that the temperature change of the heater 11 due to the sheet passing can be detected quickly, and the temperature ripple due to the sheet passing can be reduced.

The conventional heater 41 (FIGS. 14 and 15) and the upstream thermistor heater 11 of this example were compared for temperature ripple during sheet passing. The results are shown in Table 2.

[0090]

[Table 2] As can be seen from Table 2, the upstream thermistor heater 11 has a smaller temperature ripple during the passage of the paper, which enables better temperature control.

From the above results, the thermistor 11e as a temperature detecting member is arranged on the rear surface heating heater upstream of the fixing nip portion N in the sheet feeding direction a with respect to the widthwise center O of the fixing nip portion N. It was possible to reduce the temperature ripple.

Reference Example 3 (FIG. 7) The heater of this example is the same as the heater 11 of the back surface heating type (FIGS. 3 and 4) of the first embodiment, and as shown in FIG. A heat insulating layer 17, which is a glass layer having a thickness of 50 μm in this example, is formed so as to cover the resistance heating layer 11b and the thermistor 11e on the back surface of the heater.

The heat insulating layer 17 described above can further reduce the heat leak to the back side of the heater 11 of the back surface heating type heater 11 of the first embodiment and improve the heat efficiency of the fixing nip portion N side. .

The back surface heating type heater having the heat insulating layer 17 and the back surface heating type heater having no heat insulating layer 17 were compared with each other for the dependency of the fixing power on the input power. The results are shown in Table 3.

[0095]

[Table 3] As can be seen from Table 3, the heat insulating layer 17 is provided on the back side of the heater substrate on which the resistance heating layer is provided for the back surface heating type heater.
By providing the above, heat leak to the back side of the heater is further reduced, and efficient heat fixing can be performed.

In this example, the heat insulating layer 17 has a thickness of 50 μm.
m glass layer was used, but PI / P with a thickness of 10 μm or more
Similar heat insulation effect with FA / PTFE etc. was obtained.

From the above results, by providing the heat insulating layer 17 on the back side of the heater substrate in which the resistance heating layer 11b and the thermistor 11e are provided for the back side heating type heater, the heat leak to the back side of the heater is further reduced, and the efficiency is improved. It has become possible to perform good heat fixing.

<Example of First Embodiment> (FIG. 8) The heater 11 of this example has a heater substrate 11a as shown in FIG.
The resistance heating layer 11b on the back side of the
Like the conventional heater 41 of the above, it is formed and equipped with a single structure, and the high heat conductive insulating member 18 is provided on the resistance heating layer 11b. In this example, the temperature detection of a thermistor or the like is performed through an aluminum nitride plate having a thickness of 0.5 mm. The member 11e is arranged in contact with the heater 11e to control the temperature of the heater 11. Heater substrate 11
a is an aluminum nitride substrate.

The fixing film 13 is slidably moved in the fixing nip portion N in close contact with the heater surface, that is, a single surface of the heater substrate 11a.

In this structure, since the thermistor 11e is brought into contact with the resistance heating layer 11b through the high heat conductive member 18, the temperature change detection speed is increased, and temperature control with less temperature ripple can be performed.

Further, since the thermistor 11e is brought into contact with the resistance heating layer 11b via the insulating member 18, the insulation distance between the primary (resistance heating layer 11b side) and secondary (thermistor 11e side) can be maintained. it can. Therefore, the substrate 11a
The width can be reduced, and heat fixing can be performed at low cost and in a small space.

A comparison was made between the conventional heater 41 (FIGS. 14 and 15) and the rear surface heating heater 11 having the structure of this example with respect to uneven fixing property in a low temperature environment (15 ° C.) and temperature ripple at the time of sheet passing. The results are shown in Table 4.

[0103]

[Table 4] As can be seen from Table 4, the rear surface heating heater 11 having the configuration of this example
It can be seen that the paper has a small temperature ripple due to the passing of the paper, and can be uniformly heated and fixed over the entire surface of the paper. Further, the thickness of the aluminum nitride plate as the high thermal conductive insulating member 18 brought into contact with the resistance heating layer 11b was 0.5 to 1 mm, and the same effect was obtained.

As can be seen from the above results, by arranging the temperature detecting member 11e in contact with the heating resistor layer 11b on the back side of the backside heater 11 through the high thermal conductive insulating member 18, the efficiency can be reduced in a small space. Heat fixing with a small temperature ripple is now possible.

Second Embodiment Example (FIG. 9) In this example, as shown in FIG. 9, the rear surface heating heater 11 according to the first embodiment described above has a heating resistor layer 11 on the back surface side of the heater.
The high heat conductive insulating member 18 (aluminum nitride plate) was brought into contact with b through the high heat conductive insulating grease 19 as a high heat conductive fluid. Other configurations are the same as those of the heater 11 of the fourth embodiment.

In this structure, the high thermal conductive insulating member 18 is used.
It is possible to prevent erroneous detection of the heater temperature and delay in response due to poor contact with the resistance heating layer 11b, and to perform temperature control with small temperature ripple between units.

A unit of temperature ripple when the high heat conductive insulating member 18 (aluminum nitride plate) is brought into contact with the heat generating resistance layer 11b on the rear side of the heater through the high heat conductive insulating grease 19 and when not. The differences were compared.
The results are shown in Table 5.

[0108]

[Table 5] As can be seen from Table 5, the heating resistance layer 11 on the back side of the heater
By bringing the high thermal conductive insulating member 18 into contact with b via the high thermal conductive insulating grease 19, and disposing the temperature detecting member 11e in contact with the high thermal conductive insulating member 18,
Variability between units has been reduced, and stable temperature control with small temperature ripple has become possible.

The same effect was obtained when the high thermal conductive insulating member 18 was adhesively fixed on the resistance heating layer 11b using the high thermal conductive insulating adhesive.

As can be seen from the above results, the high thermal conductive insulating member 18 is attached to the heating resistance layer 11b on the back side of the heater.
By bringing the high heat conductive insulating grease 19 into contact with the high heat conductive insulating grease 19 and disposing the temperature detecting member 11e in contact with the high heat conductive insulating member 18, it is possible to stably perform temperature control with a small temperature ripple.

Reference Example 4 (FIG. 10) In this example, as for the rear surface heating heater 11 (FIG. 6) of the second embodiment, as shown in FIG. On the side, a diamond-like thin film 30 having an amorphous structure was formed as a high heat conduction lubricating layer (high heat conduction hard layer). The other configuration is the same as that of the heater 11 of Reference Example 2 .

This amorphous diamond-like thin film 30
Is formed by a plasma CVD method in which methane (CH ₄ ) gas is decomposed by glow discharge, and is in an amorphous state between graphite and diamond. Its features are that its color is black, its hardness is as high as 3000 Vg / mm ^{2 in} Vickers hardness, and its heat resistance is as high as about 400 ° C.
Thermal conductivity is 5.0 × 10 ⁻³ (cal / cm · s · de)
g) and the material cost is very low due to the use of CH ₄ .

In this structure, the heater 11 and the fixing film 1 are
Since the slidability of No. 3 is improved, abrasion in the film plane can be prevented. Further, since the diamond-like thin film 30 which is a high heat conductive film is used, efficient heat fixing can be performed without lowering the heat transfer efficiency.

To compare the levels of the inner surface of the film with and without the diamond-like thin film layer 30 on the film rubbing surface (heater substrate surface side) of the heater 11, the paper passing durability was performed. The results are shown in Table 6.

[0115]

[Table 6] As can be seen from Table 6, in the case where the diamond-like thin film 30 is not formed, film scraping occurs at 200,000 sheets,
With the diamond-like thin film 30, no film scraping occurred even after passing 250,000 sheets.

Next, the fixability was confirmed with and without the diamond-like thin film 30. The results are shown in Table 7.

[0117]

[Table 7] As can be seen from Table 7, even if the diamond-like thin film 30 is formed, good fixing property can be obtained without lowering the thermal efficiency. The same effect was confirmed when the thickness of the diamond-like thin film 30 was 5 to 50 μm.

As can be seen from the above results, by providing the high thermal conductive hard layer 30 on the heater substrate surface side, which is the film rubbing surface of the rear surface heating heater 11, the in-plane abrasion of the film is prevented without lowering the thermal efficiency. I was able to.

Reference Example 5 (FIG. 11) In this example, as for the rear surface heating heater 11 (FIG. 6) of Reference Example 2 , as shown in FIG. A hard chrome layer 30a is provided as a conductive / high heat conduction lubricating layer (hard conductive layer), and the hard chrome layer 30a is grounded or grounded via a diode. Instead of this hard chrome layer, a metal thin film of Zn, Co, Ni or the like can also be used. Other configurations are reference examples
It is the same as the second heater 11.

In this structure, not only is the hard chrome layer 30a prevented from abrading the inner surface of the fixing film without deteriorating the fixability, but the hard chrome layer 30a is grounded or grounded via a diode to prevent excessive fixing film 13. It is considered that charging can be prevented and toner offset can be prevented.

The difference in fixing property and durability depending on the presence or absence of the chrome layer 30a was compared. The results are shown in Table 8.

[0122]

[Table 8] As can be seen from Table 8, by providing the chromium layer 30a on the heater substrate surface side, which is the film rubbing surface of the rear surface heating heater 11, it was possible to prevent the inner surface of the fixing film from being scraped without degrading the fixing property.

Next, the electrostatic offset under the low temperature and low humidity environment was evaluated. The results are shown in Table 9.

[0124]

[Table 9] As can be seen from Table 9, by forming the hard chrome layer 30a on the heater substrate surface side, which is the film rubbing surface of the rear surface heating heater 11, and grounding it through a ground or a diode, the electrostatic offset in a low temperature and low humidity environment can be reduced. Improved.

As can be seen from the above results, a high heat conductive hard conductive layer 30a such as a hard chrome layer is provided on the heater substrate surface side which is the film rubbing surface of the rear surface heating heater 11, and the conductive layer 30a is grounded or connected to a diode. By grounding through the film, the inner surface of the film can be prevented from being scraped without lowering the thermal efficiency, and the electrostatic offset can be prevented.

Reference Example 6 (FIG. 12) In this example, in the rear surface heating heater 11 (FIG. 10) of Reference Example 4 , the fixing nip portion on the heater substrate surface side, which is the film sliding surface of the heater 11, is connected to the outside of the fixing nip portion. A heat-insulating lubricating film 30b (heat-insulating lubricating layer), specifically, a glass film layer conventionally used as a glass protective layer was formed on the downstream side in the paper direction. The other configurations are the same as those of the heater 11 of the reference example 4 .

In this configuration, the heat insulating layer 30b is provided on the downstream side in the sheet passing direction outside the fixing nip portion, so that the fixing nip portion N
It is considered that the heating on the downstream side in the paper feeding direction is relaxed, and the paper (recording material P) can be cooled and separated from the surface of the fixing film 13.

The heat insulating layer 30 is provided on the downstream side outside the fixing nip portion.
The separability of paper was compared between the case with b and the case without b. The results are shown in Table 10.

[0129]

[Table 10] As can be seen from Table 10, the winding of the paper can be prevented by providing the heat insulating layer 30b on the downstream side in the paper passing direction outside the fixing nip portion on the heater substrate surface side which is the film rubbing surface of the back surface heating heater 11. It was

As can be seen from the above results, the efficiency is lowered by forming the heat insulating layer 30b on the downstream side in the fixing nip portion outside the sheet feeding direction on the heater substrate surface side which is the film rubbing surface of the back surface heating heater 11. It has been found that not only can the film be prevented without it, but the paper can also be prevented from wrapping around the film.

Third Embodiment (FIG. 13) (a), (b), and (c) of FIG. 13 are schematic diagrams of other structural examples of a film heating type heating device (heat fixing device), respectively. .

In (a), the first film suspending roller 31, the second film suspending roller 32, and the heater (heating body) 11 fixedly supported by the stay holder 12 are arranged in parallel with each other. An endless belt-shaped fixing film (heat-resistant film material) 13 is stretched around the members 31, 32 and 11, and the fixing film 13 is sandwiched between the members to be pressed against the heater 11 to dispose the pressure roller 20. The fixing film 13 is rotatably conveyed by using the first film suspension roller 31 or the pressure roller 20 as a film driving roller. When the first film suspension roller 31 is used as a driving roller, the pressure roller 20 is driven to rotate.

In the case of (b), the heater 11 fixedly supported by the stay holder 12 and one film suspension roller 3 are used.
The endless belt-shaped fixing film 13 is suspended between the two members 11 and 33 of No. 3, and the pressure roller 20 is disposed in pressure contact with the heater 11 with the fixing film 13 interposed therebetween. The film suspension roller 33 or the pressure roller 20 is rotated and conveyed as a film driving roller. When the first film suspension roller 33 is used as a driving roller, the pressure roller 20 is driven to rotate.

In the case of (c), the fixing film 13 is not an endless belt-like one, but a long end film wound in a roll is used.
Heater 11 fixedly supported by a stay holder 12 from the side
And the pressure roller 20 is pressed against the heater 11 with the fixing film 13 interposed therebetween.
The fixing film 13 is configured to travel and be conveyed to the winding shaft 35 side. The pressure roller 20 may be a film driving roller.

In the above various devices, the heater 11 is the first
It is a heater having the configuration of the first or second embodiment.

<Others>

1) The number and the formation pattern of the resistance heating elements 11b of the heater 11 are not limited to those of the embodiment, and are arbitrary.

2) When a plurality of resistance heating elements 11b are provided, each resistance heating element has a resistance value per unit length, a material,
The width, thickness, etc. can be made different.

[0139]

3) The heating device of the present invention is not only the fixing device of the embodiment, but also a device for heating the image-recorded recording material to modify the surface properties (luster etc.), a hypothetical fixing device, It can be widely used as a heating device such as a device for drying treatment or thermal laminating treatment.

[0141]

As described above, according to the present invention, the spine
Film heating method using surface heating type heating element
For the device, the temperature change detection speed becomes faster and the temperature
It is possible to control the temperature control with less pluck. Primary (resistance heating
Keep the insulation distance between layer side) -secondary (temperature detection member side)
Therefore, it is possible to reduce the width of the board and reduce the cost.
Heat fixing is possible in a small space.

[Brief description of drawings]

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

FIG. 2 is a schematic configuration model diagram of a heat fixing device in Reference Example 1 .

FIG. 3 is an enlarged cross-sectional model view of a main part of the heat fixing device.

FIG. 4 (a) is a model view of a surface of a heater (heating body) with the middle part omitted, and FIG. 4 (b) is a rear model view with the middle part omitted.
(C) is a side view with the middle part omitted

FIG. 5 is an enlarged cross-sectional model view of a main part of a conventional type heater or a heat fixing device including the heater.

FIG. 6 is an enlarged cross-sectional model view of a heater in Reference Example 2 or a main part of a heat fixing device including the heater.

FIG. 7 is an enlarged cross-sectional model diagram of a heater in Reference Example 3 or a main part of a heat fixing device including the heater.

FIG. 8 is an enlarged cross-sectional model view of a main part of a heater or a heating and fixing device including the heater according to the first embodiment .

FIG. 9 is an enlarged cross-sectional model view of a main part of a heater or a heating and fixing device including the heater according to the second embodiment .

FIG. 10 is an enlarged cross-sectional model diagram of a main part of a heater or a heat fixing device including the heater in Reference Example 4 ;

FIG. 11 is an enlarged cross-sectional model view of a main part of a heater or a heat fixing device including the heater in Reference Example 5 .

FIG. 12 is an enlarged cross-sectional model view of a heater in Reference Example 6 or a main part of a heat fixing device including the heater.

13 (a), (b), and (c) are schematic diagrams of other configuration examples of a film heating type heating device (heat fixing device).

FIG. 14 is a schematic cross-sectional view of a main part of a film heating type heating device (heat fixing device).

FIG. 15 (a) is a model view of the heater (heating body) with the middle part omitted and partially cut away, and FIG. 15 (b) is a rear model view with the middle part omitted.

[Explanation of symbols]

1 Photosensitive drum (image carrier) 2 charging roller 3 Laser beam scanner 4 Developing device 5 Transfer roller 6 Heat fixing device 10 Fixing member (heater / fixing film assembly) 20 Pressure member (pressure roller) 11 Heater 12 Stay holder (heater support) 13 Fixing film (heat resistant thin film material) 11a Resistance heating layer 11e Temperature detection member (thermistor) N fixing nip P Heated material (recorded material, transfer material)

─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Masami Takeda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Masahiro Goto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-6-202511 (JP, A) JP-A-5-134570 (JP, A) JP-A-2-163780 (JP, A) JP-A-2-145931 (JP, A) JP-A-5-343168 (JP, A) JP-A-4-9888 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 13/20 G03G 15/20

Claims (2)

(57) [Claims] 1. An aluminum nitride substrate and this substrate
Heating body having resistance heating layer formed on one surface
And the surface of the heating element opposite to the surface on which the resistance heating layer is provided.
With the film that moves while touching, through the film
The heating device that heats the material to be heated with the heat from the heated
Te, the heating body the aluminum nitride in the resistance heating layer on the
The temperature detecting member is installed through the high thermal conductive insulating member of
A heating device characterized by being. 2. The high thermal conductive insulating member is a high thermal conductive insulating member.
Being in contact with the resistance heating layer through a conductive grease
The heating device according to claim 1, wherein: