JP2001028289A - Roll-like heater and fixing device using the roll-like heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively transfer heat generated from an exothermic sheet to a roll-like heater (a fixing roller), and also to enable replacement of the exothermic sheet, in the case of breakage of the exothermic sheet. SOLUTION: In this roll-like heater 10, an exothermic sheet 13 is formed with a resistance material 13b on one surface of a heatresistant insulator film 13a. A heat conductor 14a, such as phosphor bronze is stuck onto the other surface of the exothermic sheet 13 with a heat-resistant adhesive to form a detachable sheet 14. An adhesive 15 such as a silicone grease is thinly applied onto a surface of the heat conductor 14a of the detachable sheet 14, the detachable sheet 14 is rolled up with the adhesive-applied surface outside, and the detachable sheet 14 is inserted into a core metal 11 of the roll-like heater 10. The phosphor bronze of the rolled heat conductor 14a spreads inside the core metal 11 by elasticity, so that a phosphor bronze surface applied with the adhesive 15 comes into pressure-contact with the inside of the core metal 11. The detachable sheet 14 sticks fast to the inside surface of the roll-like heater 10 due to the viscosity of the silicone grease.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roll-shaped heater and a fixing device using the roll-shaped heater. More specifically, the present invention relates to a heat-generating resistor formed in a sheet shape and mounted on the inner peripheral surface of a cylindrical member. The present invention relates to a roll-shaped heater configured and a fixing device for an image forming apparatus using the roll-shaped heater.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus, a photosensitive member is first uniformly charged, and the photosensitive member is exposed by an exposure source such as a laser beam in accordance with image information to form an electrostatic latent image.
The electrostatic latent image on the photoreceptor is developed by a developer (toner) to be visualized, and the developed image is transferred to a recording medium such as a recording paper by a transfer unit, and then the developer is applied to the recording paper by a fixing device. Is heat-fixed to form an image.

As the fixing device, for example, a fixing device in which a fixing roller and a pressure roller are installed facing each other is used. A developer (toner) image on a recording paper is inserted between the two rollers. Heat and pressure bonded. The fixing roller has a metal core such as aluminum formed in a cylindrical shape, for example, and a release layer coated with fluorine on the outer peripheral surface. In addition, a halogen lamp is mainly used as a heater inside the metal core, and power is supplied to the halogen lamp to generate heat, and the heat heats the entire fixing roller.

[0004] Such a fixing roller using a halogen lamp has a problem in that since an air layer is present between the halogen lamp and the core metal, heat conduction to the fixing roller is poor and it takes time for the fixing roller to warm.

In order to solve this problem, it has been proposed to provide a resistance heating element on the inner surface of the fixing roller and heat the resistance heating element itself to directly heat the fixing roller without an air layer. Such a fixing roller is disclosed, for example, in JP-A-8-220915. According to Japanese Patent Application Laid-Open No. Hei 8-220915, a resistance heating member is made of a flexible material in which a resistance heating element made of a resistance member having a predetermined pattern formed on an insulating film material having heat resistance and insulation properties is attached. The heating element sheet is inserted into the roller such that the resistance heating element faces the central axis of the fixing heating roller. A pair of belt-shaped power supply portions extending in the circumferential direction of the roller main body are formed at both ends of the fixing heat roller main body, and are electrically connected to the resistance heating element. When a pair of electrodes are slidably contacted with the power supply unit, current is supplied to the resistance heating element through the power supply unit, and the current is supplied to the resistance heating element, whereby the entire heating roller for fixing is heated. In this conventional example, in the heating element sheet having the above configuration, there is a possibility that a gap may be formed between the sheet at one end and the other end in the circumferential direction. In this way, the power supply unit is configured to reliably supply current to the resistance heating element. Further, in this conventional example, the method of fixing the heating element sheet in the fixing heating roller is to apply a heat-resistant adhesive to the back surface of the insulating film material and heat the resistive heating element in a high-temperature furnace to form the resistance heating element on the roller body. It is configured to be fixed to the inner peripheral surface. Further, Japanese Unexamined Patent Publication No.
JP-A-305197 discloses a heating element sheet in which a resistance heating member having a predetermined pattern is attached to one surface of an insulating film material.
There is disclosed a flexible configuration in which a heat conductor is attached to the other side. In this conventional example, through-holes are formed in both ends of the heating element sheet and the roller body, and caulking members as fixing members are fitted in accordance with these through-holes, and the heating element sheet is fixed to the inner periphery of the roller body. It is fixed in a state in contact with the surface, or is fixed using a heat-resistant adhesive.

A heat-resistant insulating layer having a heating element (heating sheet)
A method of fixing the heat-fixing roller to the heat-fixing roller using a means that does not require an adhesive action is disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 9-138605. According to Japanese Patent Application Laid-Open No. Hei 9-138605, as a means that does not require an adhesive action, a heat-resistant insulating layer is inserted inside a heat fixing roller, and a pressure contact body such as a rubber elastic body is further inserted inside the heat fixing roller. The heat-resistant insulating layer is fixed by applying pressure to the outside of the heat fixing roller by a body. According to this method, since the heat-resistant insulating layer is fixed to the inner surface of the heat-fixing roller, even if the heat-resistant insulating layer is damaged, it can be replaced.

[0007]

SUMMARY OF THE INVENTION However, Japanese Patent Application Laid-Open No. Hei 8-2
In the conventional methods as disclosed in JP-A-20915 and JP-A-8-305197, the heating element sheet is fixed to the fixing heating roller with an adhesive or a caulking member. If it is damaged and replaced, it is impossible or difficult to remove. Further, disclosed in JP-A-8-305197,
In the method in which both ends of the heating element sheet are fixed by using a caulking member, a force is partially applied to the heating element sheet, so that the heating element sheet and the roller body do not evenly adhere to each other, and air is partially interposed therebetween. Layers may be formed. The air layer has poor thermal conductivity, and thus causes a problem that the heating efficiency is reduced and temperature unevenness occurs.

In the conventional method disclosed in Japanese Patent Application Laid-Open No. 9-138605, when a heat fixing roller is heated by using a pressing member, heat generated in the heat-resistant insulating layer is transferred to a metal pipe (core). Gold) is heated at the same time as the press-contact body disposed inside the heat-resistant insulating layer is heated, so that it cannot be said that the surface of the heat-fixing roller is efficiently heated. Particularly during warm-up, it takes time to raise the temperature.
Therefore, in order to efficiently transfer the heat generated from the heat generating sheet to the fixing roller, it is preferable that nothing is provided inside the heat generating sheet.

The present invention has been made to solve the above-described problems of the prior art, and uses a viscous agent as a means for bringing a heat generating sheet into close contact with a fixing roller (roll-shaped heater). A fixing roller (roll-shaped heater) and a fixing roller in which the heat generating sheet is closely adhered to the fixing roller due to the viscosity, heat generated from the heat generating sheet is efficiently transferred to the fixing roller, and even if the heat generating sheet is damaged, it can be replaced. It is an object of the present invention to provide a fixing device using the same.

[0010]

According to a first aspect of the present invention, there is provided a roll-shaped heater comprising a cylindrical roller member and a heating sheet having a resistance heating member formed on one surface of an insulating member. The heat generating member is fixed to the inner peripheral surface of the roller member with a viscous agent having thermal conductivity in a state where the resistance heating member faces the cylindrical axis of the roller member. According to the above configuration, since the heat generating sheet is fixed to the inner peripheral surface of the roller member by the viscous agent having thermal conductivity, the heat generating sheet can be easily replaced when the heat generating sheet is damaged. Further, since the viscous agent can be applied uniformly and has thermal conductivity, the roller member can be efficiently heated without causing temperature unevenness.

According to a second aspect of the present invention, in the roll-shaped heater according to the first aspect, the heat generating sheet has elasticity on a surface of the insulating member opposite to a surface on which the resistance heat generating member is formed. Is provided. According to the above configuration, in addition to the function of the first aspect, the heat generating sheet is provided on the surface of the insulating member opposite to the surface on which the resistance heat generating member is formed. Since the roller member is fixed to the inner peripheral surface of the roller member, the adhesion can be further improved.

According to a third aspect of the present invention, in the roll-shaped heater according to the second aspect, the elastic heat conductor is made of phosphor bronze. According to the above configuration, in addition to the function of the second aspect, since phosphor bronze is used as the heat conductor, it can be manufactured at low cost without deteriorating good heat conductivity and elasticity.

According to a fourth aspect of the present invention, in the roll-shaped heater according to the first aspect, the viscous agent having thermal conductivity comprises:
It is characterized by being made of silicone grease. According to the above configuration, in addition to the function of the first aspect, by using a general-purpose silicone grease as the heat conductive viscous agent, the heat generation sheet can be easily brought into close contact with the roller member.

According to a fifth aspect of the present invention, there is provided a fixing device using a roll-shaped heater according to any one of the first to fourth aspects, and a pressing member provided in pressure contact with the roll-shaped heater. Wherein the recording medium carrying the unfixed toner image is conveyed to a pressure contact portion between the roll-shaped heater and the pressing member to perform fixing. According to the above configuration, in addition to the function of any one of claims 1 to 4, the fixing device is provided with a roll-shaped heater in which the heat generating sheet is in close contact with the inner peripheral surface of the roller member by a viscous agent having thermal conductivity. By applying the fixing device, it is possible to provide a fixing device having excellent performance and maintainability, such as quick warm-up time and easy replacement even when the heat generating sheet is damaged.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a roll-shaped heater and a fixing device using the roll-shaped heater of the present invention will be described based on embodiments shown in the drawings. In the embodiment of the present invention, a case will be described in which the fixing device is applied to a monochrome laser printer as an electrophotographic device. As shown in FIG. 7, the laser printer of this embodiment
It comprises an image forming device 40, a laser scanning unit 50, a fixing device 60 and the like.

The laser printer having the above-described configuration includes
Transports the sheet P (recording medium) to the image forming apparatus 40 from the printer. In the image forming apparatus 40, a toner image is formed based on the laser beam 54 from the laser scanning unit 50, and the toner image is transferred onto the conveyed sheet P (recording medium).
The sheet P on which the toner image has been transferred is transported to the fixing device 60, and the toner image is fixed on the sheet P. Finally, the sheet P on which the toner image has been fixed is discharged outside the apparatus by sheet conveying rollers 71 and 72 provided on the sheet conveying downstream side of the fixing device 60. That is, the sheet P is conveyed in the order of the sheet feeding tray 31, the image forming apparatus 40, and the fixing device 60 along the path of the arrow E shown in the figure, and is discharged outside the apparatus.

The paper supply section 30 has a paper supply tray 31, a paper supply roller 32, a paper separation friction plate 33, a pressure spring 34, a paper detection actuator 35, a paper detection sensor 36, and a control circuit 37. Upon receiving a print command, the sheets P mounted on the sheet feed tray 31 are fed one by one by the action of a sheet feed roller 32, a sheet separating friction plate 33, and a pressure spring 34, and are fed into the printer.

The fed sheet P inverts the sheet detection actuator 35 and outputs it as an electric signal to the sheet detection optical sensor 36 to instruct the start of image printing. Control circuit 37 activated by the operation of paper entry detection actuator 35
Sends an image signal to the laser diode light emitting unit 51 of the laser scanning unit 50, and controls lighting or non-lighting of the laser diode.

The laser scanning section 50 includes the laser diode light emitting unit 51, a scanning mirror 52, a scanning mirror motor 53, and reflection mirrors 55, 56, 57. The scanning mirror 52 is rotated at high speed and constant speed by a scanning mirror motor 53. That is, in FIG.
Scans in a direction perpendicular to the paper surface. Laser light 5 emitted from laser diode light emitting unit 51
The reference numeral 4 irradiates the photosensitive member 41 to be described later via the reflection mirrors 55, 56, and 57. At this time, the laser light 54 selectively exposes the photoreceptor 41 on the basis of light-on or light-off information from the control circuit 37. Image forming apparatus 40
Includes a photosensitive member 41, a transfer roller 42, a charging member 43, a developing roller 44, a developing unit 45, and a cleaning unit 46.

The laser beam 54 is used to charge the charging member 43 in advance.
The surface charge is selectively discharged from the photoreceptor 41 charged by, and an electrostatic latent image is formed. Toner T used for development
Are stored in the developing unit 45. Developing unit 4
The toner T, which has been given a charge by moderate stirring in 5, adheres to the surface of the developing roller 44 and forms an electrostatic latent image by the action of a developing bias voltage applied to the developing roller 44 and an electric field generated by the surface potential of the photoconductor. The corresponding toner image is transferred to the photoconductor 41.
Can be formed on.

The paper P conveyed from the paper supply unit 30 is
The sheet is sent between the photoconductor 41 and the transfer roller 42. Then, the toner T on the photoconductor 41 is electrically attracted and transferred onto the paper P by the action of the electric field given by the transfer voltage applied to the transfer roller 42. At this time, the toner T on the photoconductor 41 is transferred to the sheet P by the transfer roller 42 (FIG. 1), and the untransferred toner is collected by the cleaning unit 46.

Thereafter, the sheet P is transported to the fixing device 60. Therefore, an appropriate temperature and pressure are applied by the pressure roller 20 and the fixing roller 10 maintained at a predetermined temperature.
Then, the toner dissolves and is fixed to the paper P to form a robust image. The paper P is transported by the paper transport rollers 71 and 72 and is discharged outside the machine.

Next, the fixing device 60 will be described with reference to FIGS.
This will be described in detail based on FIG. The fixing device 60 includes a fixing roller 10 formed of a roll-shaped heater and a pressure roller 20 disposed opposite to the fixing roller 10, and is in contact with a predetermined pressure by an elastic member such as a spring. Wn in FIG. 1 indicates a nip portion formed by pressing the fixing roller 10 and the pressure roller 20 against each other.

The fixing roller 10 is driven to rotate in the direction of arrow A by driving means (not shown), and the pressure roller 20 is driven to rotate in the direction of arrow B accordingly. Pressure roller 20
Is, for example, a stainless steel core 21 having an outer diameter of 25 mmφ.
(22 mmφ) on the LTV (Low Te
mperature Valcanizing) silicone rubber layer (thickness 1.
5 mm).

The fixing roller 10 has an outer diameter of 20 mmφ and a coating layer 12 made of polytetrafluoroethylene (PTFE) formed on a hollow aluminum core 11 made of aluminum (in this case, the core 11 and the coating layer 12 are formed of a polytetrafluoroethylene (PTFE)). Roller member). A detachable heating sheet 13 is inserted inside the hollow metal core 11. The heat generating sheet 13 is composed of a hollow core 11 and a resistor (resistive heat generating member) 13b provided via a heat-resistant insulating film 13a. The resistor 13b of the heat generating sheet 13 is configured to be in contact with an external electrode. When electricity is supplied from the external electrode, the resistor 13b generates heat, and the fixing roller 10 is heated to a predetermined temperature.

A temperature detecting means (for example, a thermistor) 1 for detecting the surface temperature of the fixing roller 10 is provided near the entrance of the nip portion Wn in the rotation direction A of the fixing roller 10.
9 are arranged. The detection signal from the thermistor 19 is sent to a power supply control circuit (not shown), and the power supply to the fixing roller 10 is controlled by the power supply control circuit based on the detection signal. The material of the core metal 11 is not limited to aluminum, but may be, for example, carbon steel, glass, ceramic, high heat resistant resin, or the like.

The heat generating sheet 13 provided inside the fixing roller 10 is, for example, as shown in FIG.
A resistor 3b having a rectangular repetitive pattern formed on the entire surface of 3a is used. At both ends of the resistor 13b, electrode portions 13c that are in contact with the power supply portion are provided. Alternatively, as shown in FIG.
The heat generating sheet 13 in which the resistor 13b is disposed on each of the plurality of heat resistant insulating films 13a disclosed in No. 46138 may be used. In the heat generating sheet 13, terminal portions 13d are provided at both ends of the resistor 13b. The terminal section 13d is connected to a power receiving section (not shown) by a conductive wire, and the power receiving section is configured to be energized to the resistor 13b by contacting the power feeding section. The pattern of the resistor 13b is not limited to a rectangular repetitive pattern, but may be another pattern as long as the fixing roller 10 can be uniformly heated.

As the material of the heat-resistant insulating film 13a, a sheet-shaped heat-resistant insulating film made of polyimide is generally used, but any other heat-resistant insulating material may be used other than polyimide. As the material of the resistor 13b, stainless steel is generally used, but other materials such as copper may be used as long as they can be used as the resistor.

(Embodiment 1) First, as shown in FIG. 4, the above-mentioned heat-generating sheet 13 is attached to a heat conductor 14a having good elasticity and good thermal conductivity in the form of a detachable sheet 14 in the form of a fixing roller. A method of bringing the (roll-shaped heater) 10 into close contact with the core metal 11 will be described. The heat conductor 14a
Is used to improve the heat conductivity between the heat generating sheet 13 and the core metal 11 of the fixing roller 10 and to use the heat conductor 14a.
This is for bringing the detachable sheet 14 into close contact with the core metal 11 by using the elasticity.

A heat conductor 14a is adhered to the heat generating sheet 13 with a heat-resistant adhesive or the like to form a detachable sheet 14. The detachable sheet 14 is inserted into the core 11 in a state where it is slightly smaller than the inner periphery of the core 11 so that the surface of the resistor 13b is on the outside. The surface is directed toward the central axis of the fixing roller 10), and if the slightly rounded state is released, the surface of the heat conductor 14a of the detachable sheet 14 and the inside of the metal core 11 are in close contact.

In the present embodiment, phosphor bronze having excellent elasticity and good heat conductivity is used as the heat conductor 14a. The size of the phosphor bronze has a length corresponding to the inner circumference of the cored bar 11 of the fixing roller 10 and a width substantially equal to the length between both ends of the fixing roller 10. As other heat conductors 14a,
Stainless steel, silver, nickel chrome alloy, tungsten,
A copper-nickel alloy or the like can be used.

Next, a method for bringing the detachable sheet 14 into close contact with the core 11 will be described. The detachable sheet 14 is the core 1
Before being inserted into the inside 1, the viscous agent 15 is thinly applied to the surface of the phosphor bronze. As the viscous agent 15, for example, silicone grease is used. The viscosity of the viscous agent 15 is 100 to 500 [cP], and the thermal conductivity is 2 ×
It is preferably set to 10 ⁻³ [cal / s · cm · ° C.] or more. When the viscosity becomes lower than 100 [cP], the detachable sheet 1
There is a possibility that the adhesive force between the fixing roller 4 and the core metal 11 of the fixing roller 10 becomes weak, and the detachable sheet 14 comes off. If the viscosity is higher than 500 [cP], the adhesiveness between the detachable sheet 14 and the core metal 11 of the fixing roller 10 is deteriorated, and there is a possibility that an air layer is mixed. Further, in order to efficiently transfer the heat generated from the heat generating sheet 13 to the surface of the fixing roller 10, it is necessary to apply the viscous agent 15 as thinly as possible. A problem arises in the process. Further, the thermal conductivity is 2 × 10 ^−3.
[Cal / s.cm..degree. C.] or less, heat generation sheet 1
4, heat conductivity from the fixing roller 10 to the surface of the fixing roller 10 is reduced, and the time required to reach a predetermined temperature is undesirably increased. In this example, a silicone grease having a viscosity of 230 [cP] and a thermal conductivity of 2 × 10 ⁻³ [cal / s · cm · ° C.] was used.

The detachable sheet 14 coated with silicone grease is rounded slightly smaller than the diameter of the fixing roller 10, and both ends of phosphor bronze are slightly overlapped. At this time, the phosphor bronze is rounded so that the surface coated with the silicone grease is on the outside.

Next, the rolled phosphor bronze is applied to the fixing roller 1.
0 is inserted into the core metal 11. The rolled phosphor bronze spreads within the core 11 of the fixing roller 10 due to elasticity, and the viscous agent 1
The surface of the phosphor bronze coated with 5 is pressed into the inside of the core metal 11. At this time, the detachable sheet 14 adheres to the inner surface of the fixing roller 10 as shown in FIG. 5 due to the viscosity of the silicone grease.

The heating sheet 13 inserted into the core 11 of the fixing roller 10 is fixed in the fixing roller 10 by the elasticity of phosphor bronze and the viscosity of silicone grease. When such a method is used, even if the resistor 13b is broken, no adhesive is used between the inside of the core metal 11 and the phosphor bronze, so that the detachable sheet 14 can be removed and replaced with a new detachable sheet 14. is there.

In the first embodiment, the surface of phosphor bronze is coated with silicone grease, and then the core metal 11 of the fixing roller 10 is coated.
After applying silicone grease inside the metal core 11 in advance, the resistor 13b is
The detachable sheet 14 may be rounded and inserted into the fixing roller 10 so as to face the central axis.

The thinner the phosphor bronze is, the more efficiently the heat generated from the heat generating sheet 13 can be transferred to the coating layer 12 on the surface of the fixing roller 10. Since the elastic force applied to the outer side of the fixing roller to make the contact tight, the thickness of phosphor bronze is
It is preferable to use one having a range of about 10 to 100 μm.

Embodiment 2 In Embodiment 1, the heat conductor 14
4, a method in which a detachable sheet 14 as shown in FIG. 4 provided with a heating sheet 13 on the core 11 of the fixing roller (roll heater) 10 has been described.
The heating sheet 13 can be directly adhered to the core metal 11 without providing the 4a. This method is described in FIG.
It will be described based on.

The heat generating sheet 13 is formed such that its length matches the inner circumference of the metal core 11 of the fixing roller 10 and its width is substantially equal to the length between both ends of the fixing roller 10.
First, a thin layer of silicone grease is applied to the surface of the heat-resistant insulating film 13a of the heat generating sheet 13. The same silicone grease as that used in Example 1 was used.

The heat generating sheet 13 coated with the silicone grease is rounded so that the coated surface is on the outside, inserted into the metal core 11 of the fixing roller 10, and is provided with pressing means (not shown) (for example, a cylindrical shape when pressed). A pressure is applied to the outside of the core metal 11 of the fixing roller 10 by a means for pressing a hollow member made of a rubber material such as latex or urethane with air. Can be

Here, the heat-generating sheet 13 is inserted into the fixing roller 10 after applying silicone grease to the heat-resistant insulating film 13a. However, as described in the first embodiment, the heat-generating sheet 13 is placed inside the core metal 11 of the fixing roller 10. After applying silicone grease in advance, the heat generating sheet 13 may be rolled and inserted so that the resistor 13b faces the central axis of the fixing roller 10.

In this configuration, the heat generated by the resistor 13b can be efficiently transmitted to the surface of the fixing roller 10 because it does not pass through a heat conductor such as phosphor bronze. Further, even when the heat generating sheet 13 is damaged, it can be easily removed and replaced because no adhesive is used.

In the second embodiment, one heat generating sheet 13
3 is inserted into the cored bar 11 of the fixing roller 10 and brought into close contact therewith, but a plurality of heat generating sheets 1 as shown in FIG.
It is also possible to arrange the fixing rollers 3 in parallel in the axial direction of the fixing roller 10 and make them adhere to each other. In this case, even if the heat generating sheet 13 is partially damaged, it is economical because only the damaged portion can be replaced.

In Examples 1 and 2, the viscosity of the silicone grease was 230 [cP].
Although an example using a material of 2 × 10 ⁻³ [cal / s · cm · ° C.] is shown, depending on the material used for the detachable sheet 14 or the heat generating sheet 13, that is, the detachable sheet 1
An appropriate material may be selected according to the elasticity of the sheet 4 or the heat generating sheet 13 as a whole. At this time, the detachable sheet 14, the heat generating sheet 13, and the fixing roller 10
It is a matter of course to take into account the adhesion and thermal conductivity. The viscous agent other than silicone grease can be used as long as it has a viscosity and a thermal conductivity in the above-mentioned ranges and has good heat resistance.

[0045]

As apparent from the above description, the present invention has the following effects. According to the first aspect of the present invention, the heat generating sheet can be easily replaced by closely fixing the heat generating sheet to the inner peripheral surface of the roller member with the viscous agent. Further, when a plurality of heat generating sheets are arranged in parallel and closely adhered to the inside of the metal core, it is economical because a damaged heat generating sheet can be partially replaced. Further, heat can be efficiently transmitted to the roller member because the heat conductor is not interposed.

According to a second aspect of the present invention, as a means for fixing the heat generating sheet to the inner peripheral surface of the roller member, the heat generating sheet is formed in a detachable sheet form in which the heat generating sheet is adhered on a heat conductor having good elasticity and good heat conductivity. By forming and making close contact with the elasticity of the heat conductor and the viscosity of the viscous agent, a strong adhesive force can be obtained.
Further, since the adhesive is not used even when the heat generating sheet is damaged, the detachable sheet can be removed and replaced with a new detachable sheet.

According to the third aspect of the present invention, by using phosphor bronze as the heat conductor, heat generated from the heat generating sheet can be efficiently transmitted to the surface of the roller member. Further, since phosphor bronze has excellent elasticity, it has good adhesion to the inner surface of the roller member. Further, since the material is inexpensive, cost reduction can be achieved.

According to a fourth aspect of the present invention, a general silicone grease is used as a viscous agent having thermal conductivity, so that the thermal conductivity between the heating element sheet and the roller member can be maintained without impairing the thermal conductivity. Can be improved.

According to the fifth aspect of the present invention, it is possible to provide a fixing device capable of shortening the warm-up time because heat can be efficiently transmitted to the surface of the fixing roller composed of a roll-shaped heater. Also, since no adhesive or caulking means is used to fix the heat generating sheet to the inner peripheral surface of the roller member, if the heat generating sheet is damaged, it can be easily removed and replaced with a new heat generating sheet. is there.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a fixing device to which a roll-shaped heater of the present invention is applied.

FIG. 2 is a development view of a heating sheet applied to a roll-shaped heater.

FIG. 3 is a development view of different heating sheets applied to a roll-shaped heater.

FIG. 4 is a schematic side view showing a relationship between a heat generating sheet applied to a roll-shaped heater and a detachable sheet.

FIG. 5 is a sectional view of a roll-shaped heater.

FIG. 6 is a cross-sectional view of a different roll-shaped heater.

FIG. 7 is a schematic sectional view of a printer to which the fixing device of the present invention is applied.

[Explanation of symbols]

Reference Signs List 10 roll heater (fixing roller), 11 core metal (roller member), 12 coating layer (roller member), 13 heating sheet, 13a heat-resistant insulating film, 13b resistor (resistance heating member) .., 13c... Electrode part, 13d.
... Removable sheet, 14a ... Heat conductor, 15 ... Viscous agent, 19
... Temperature detecting means, 20 ... Pressurizing roller (pressing member), 21
... Core metal, 22 release layer, 30 paper feed unit, 40 image forming device, 41 photoreceptor, 42 transfer roller, 50 laser scanning unit, 60 fixing device, P paper, Wn nip Department.

Continued on the front page (72) Inventor Toshiaki Kagawa 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka F-term (reference) 2H033 AA36 BB19 BB21 3K058 AA86 AA87 BA18 CE13 CE19 DA04 GA06

Claims (5)

[Claims] 1. A roll-shaped heater comprising a cylindrical roller member and a heating sheet having a resistance heating member formed on one surface of an insulating member, wherein the heating sheet has a resistance heating member having a cylindrical shaft of the roller member. A roll-shaped heater fixed to the inner peripheral surface of the roller member with a viscous agent having thermal conductivity in a state facing the roller. 2. The heat generation sheet according to claim 1, wherein the heat generation sheet has an elastic heat conductor provided on a surface of the insulation member opposite to a surface on which the resistance heat generation member is formed. Roll heater. 3. The roll-shaped heater according to claim 2, wherein the heat conductor having elasticity is made of phosphor bronze. 4. The roll-shaped heater according to claim 1, wherein the viscous agent having thermal conductivity is made of silicone grease. 5. A recording medium comprising the roll-shaped heater according to claim 1 and a pressing member provided in pressure contact with the roll-shaped heater, wherein a recording medium carrying an unfixed toner image is formed. A fixing device, wherein the fixing device is conveyed to a pressure contact portion between the roll-shaped heater and the pressing member to perform fixing.