JP2001051547A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a fixing device which is capable of embodying a longer life of a temperature detecting member without damaging a roller coated with silicone rubber. SOLUTION: The temperature detecting member in abutment on the surface of the roller coated with the silicone rubber is constituted by disposing a molding 31 of a heat resistant foamed material on the free end side of a metal plate member 32, arranging a thermistor element in the molding and double coating the entire part thereof with an inner layer polyimide film 33 and outer layer 'Teflon (R)' film 34 adhered to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device in an image forming apparatus such as a printer, a facsimile, a copying machine, etc., and more particularly to a fixing device in which a roller for holding and conveying a sheet is covered with silicone rubber.

[0002]

2. Description of the Related Art In an image forming apparatus using toner for forming a visible image, in order to fix a toner image on a recording material, the recording material is sandwiched between a heating roller (also referred to as a fixing roller) and a pressure roller. 2. Description of the Related Art A heating and pressing type fixing device for fixing a toner image on a recording material while conveying the same is generally used.

FIG. 4 shows a fixing device of a full-color copying machine as an example of such a heating and pressing type fixing device. Sign 1
Is a fixing roller, 2 is a temperature fuse, 3 is an oil application roller, 4 is an oil supply roller, 5 is an oil application felt,
7 is a fixing roller temperature detecting member, 8 is a pressing roller cleaning roller, 9 is a pressing roller heater, 10 is a pressing roller, 11 is a pressing roller temperature detecting member, 12 is a fixing roller heater, 13 is a cleaning roller, Reference numeral 14 denotes a scraper that contacts the cleaning roller, and 15 denotes a transport belt. The fixing roller 1 and the pressure roller 10 have a diameter of, for example, 5 mm.
1mm core metal is covered with 2mm silicone rubber and 5mm
Finished to 5mm diameter.

[0004] Oil is supplied from a not-shown oil tank to an oil application felt 5 via a tube, transmitted to an oil supply roller 4 and an oil application roller 3, and applied to the surface of the fixing roller 1. The applied silicone oil is regulated by the blade 6.

The temperature detecting members 7 and 11 are usually thermistors as shown in FIG. 5, and are composed of a silicone sponge 21, a leaf spring 22 supporting the sponge, and a film 23 covering these. The thermistor element is embedded in the silicone sponge 21.

[0006]

In the case of a monochrome copying machine, since the surface of the fixing roller is covered with Teflon, the surface μ is low, and the covering film 23 is made of a generally used Kapton (polyimide). Even if it did, no problem occurred, but in color copying machines, the fixing roller and the pressure roller are often covered with silicone rubber,
In such a configuration, the friction resistance between the thermistor and the surface of the thermistor, which is a temperature detecting member, increases. The reason for this is due to the respective material properties of Teflon and silicone rubber. Particularly, silicone rubber has tackiness called tackiness, which is a major factor.

Usually, when the roller is rotating in the direction shown in FIG. 4, it is formed so that a large load is not applied to the thermistor. However, when the recording sheet is jammed, the roller is turned using a knob (not shown). To reverse. In such a case, as shown in FIGS. 6 and 7, the polyimide film 23 may be torn, the leaf spring 22 may be bent, temperature may not be controlled properly, or the contact pressure of the fixing / pressure roller may increase. As a result, the roller may be damaged.

[0008] Further, even if the rotation is not reversed, in the above-described configuration, when the paper is continuously passed, the silicone oil is sufficiently supplied to the fixing roller, but since the pressure roller is not provided with the coating member, The oil is supplied from the fixing roller slightly between the paper feeds, that is, between the papers being conveyed, and the oil is rotated in a state where the oil is insufficient. At this time, as shown in FIG. 8, the film 23 was peeled off, and the thermistor element itself came into contact with the pressure roller and damaged the roller.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fixing device which can solve the above-mentioned problems and can extend the life of a temperature detecting member without damaging a roller coated with silicone rubber. .

[0010]

According to the present invention, a temperature detecting member contacting the surface of a roller coated with silicone rubber is provided with a heat-resistant foam material on the free end side of a metal plate member. A formed body is disposed, a thermistor element is disposed in the formed body, and the entire body is composed of an inner polyimide film and an outer Teflon film adhered to each other.
The problem is solved by being configured to be heavily covered.

In the temperature detecting member, a formed body of a heat-resistant foam material is disposed on a free end side of a metal plate member, a thermistor element is disposed in the formed body, and these are entirely formed of a Teflon film. The above-mentioned problem can be solved even if the configuration is made by coating.

It is preferable that a metal plate is attached to the roller contact surface of the formed body. In a heat roller type fixing device in which a temperature detecting member for detecting the roller surface temperature is in contact with each of the rollers whose surfaces are covered with silicone rubber, and one of the rollers is provided with an applying member for applying a release agent. A temperature detecting member in contact with the roller on which the application member is provided, a formed body of a heat-resistant foam material is arranged on the free end side of the metal plate member, and a thermistor element is arranged in the formed body. The temperature detecting member is provided with a formed body of a heat-resistant foam material on a free end side of a metal plate member, and a thermistor is formed in the formed body. It is more effective to arrange the elements and cover them with an inner polyimide film and an outer Teflon film which are adhered to each other.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described based on an example shown in the drawings. FIG. 1 shows a temperature detecting member (thermistor) of the fixing device according to the present invention. The mechanism of the entire fixing device is basically the same as that of the related art. For example, as in the example of FIG. 4, the fixing roller that is in pressure contact with the pressure roller rotates clockwise and is formed by the pressure roller. The toner image is fixed by nipping the recording sheet at the nip, and a temperature fuse, an oil application device, a temperature detecting member, and a cleaning device are arranged around the fixing roller for normal fixing operation. A temperature detecting member and a cleaning device are provided around the pressure roller, and the heater is built in. For the sake of simplicity, the same parts as those of the prior art will be described in the section of the prior art, and here, only the thermistor particularly related to the present invention will be described.

In FIG. 1, a leaf spring 32 carrying a silicone rubber foam 31 having a thickness of, for example, 2 mm is made of stainless steel having a thickness of 0.1 mm.
μ thick polyimide film 33 surrounds, and
Teflon film 34 is covered. The foam body 31 is fixed with a leaf spring 32 with an adhesive, for example, the polyimide film 33 is also fixed with a leaf spring 43 with an adhesive, and the Teflon film 34 is adhered to the polyimide film 33.
The thermistor element (not shown) is embedded in the foam and is connected to a lead wire 36 via a mounting portion 35. As shown in FIG. 2, the mounting portion 35 is connected to the fixing device main body by using, for example, a screw 37 so that a sponge portion (foam) contacts the fixing roller 1. The lead wire of the thermistor wired from the mounting portion 35 to the foam 31 may be fixed with a polyimide material different from the polyimide film 33 shown in FIG. Such fixing is more excellent in workability.

FIG. 3 is a partial view of a thermistor having a different configuration so that the changed portion can be easily understood. Foam 31
A metal plate 38 having a thickness of 50 μm is attached to the upper part of the substrate, and a thermistor element 39 is in contact with the metal plate 38. By such a contact, the thermistor element does not form a convex portion on the polyimide film or the Teflon film, and can prevent the fixing roller from being damaged. Although not shown in FIG. 3, a polyimide film or a Teflon film is provided so as to surround the leaf spring 32, the foam 31, and the metal plate 38.

The fixing device having the configuration shown in FIG. 4 was attached with the thermistor of each of the above examples, and attached to an Imagio Color 2800 (a color copying machine manufactured by Ricoh). From this result, it was proved that the temperature was significantly improved as compared with the conventional temperature detecting member.

[0017]

[Table 1]

[0018]

According to the present invention, the temperature detecting member abutting on the surface of the roller coated with silicone rubber is provided with a heat-resistant foamed material formed on the free end side of the metal plate member, Since the thermistor elements are arranged in the formed body and they are entirely double-coated with an inner polyimide film and an outer Teflon film attached to each other,
Since the outermost layer of the temperature detecting member is made of Teflon and has low frictional resistance, and the Teflon layer adheres to the lower polyimide layer, the extension of the Teflon layer is suppressed, and the life is extended.

In particular, when the release agent is applied to the roller, the surface μ of the roller is low, so that the roller may be coated with only a Teflon film instead of a two-layer film of polyimide and Teflon. It is possible to achieve a sufficiently satisfactory life extension.

If a metal plate is attached to the roller contact surface of the formed body, it is possible to prevent the thermistor element from having irregularities on the roller contact surface, so that the roller is not scratched or dented.

A heat roller type in which a temperature detecting member for detecting the roller surface temperature is in contact with each of the rollers whose surfaces are covered with silicone rubber, and one of the rollers is provided with an application member for applying a release agent. In the fixing device, the temperature detecting member in contact with the roller on which the application member is attached is provided with a heat-resistant foam material formed body on the free end side of the metal plate member,
A thermistor element is arranged in the formed body, and they are entirely covered with a Teflon film. The other temperature detecting member is formed by forming a formed body of a heat-resistant foam material on a free end side of a metal plate member. It is arranged so that the thermistor elements are arranged in the formed body and they are entirely covered with a polyimide film and a Teflon film which are adhered to each other, so that the service life can be extended relatively inexpensively. Can be planned.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a configuration of a thermistor according to the present invention.

FIG. 2 is a schematic view showing a state where a thermistor is mounted.

FIG. 3 is a partial schematic view showing a thermistor according to another configuration of the present invention.

FIG. 4 is a schematic view of a heat roller type fixing device that is conventionally known and is also applied to the present invention.

FIG. 5 is a schematic sectional view showing a configuration of a conventionally known thermistor.

FIG. 6 is a schematic diagram showing an example of breakage of a conventional thermistor.

FIG. 7 is a schematic view showing an example of breakage of a conventional thermistor.

FIG. 8 is a schematic view showing an example of breakage of a conventional thermistor.

[Explanation of symbols]

 31 Silicone rubber foam 32 Leaf spring 33 Polyimide film 34 Teflon film 35 Mounting part 36 Lead wire

Claims (4)

[Claims] 1. A heat roller type fixing device in which at least one of two rollers provided with a heat source is pressed into contact with each other, and a recording material on which a toner image is placed is passed between the two rollers to fix the toner image on the recording material. A fixing device in which a temperature detecting member for detecting a roller surface temperature is in contact with at least one roller, and a roller surface in contact with the temperature detecting member is coated with silicone rubber; Is provided with a formed body of a heat-resistant foam material on the free end side of a metal plate member, a thermistor element is arranged in the formed body, and these are entirely formed by an inner polyimide film and an outer Teflon film adhered to each other. A fixing device characterized in that the fixing device is configured so as to be double coated. 2. A heat roller type fixing device in which at least one of two rollers provided with a heat source is pressed into contact with each other and a recording material on which a toner image is placed is passed between the two rollers to fix the toner image on the recording material. A fixing device in which a temperature detecting member for detecting a roller surface temperature is in contact with at least one roller, and a roller surface in contact with the temperature detecting member is coated with silicone rubber; Is formed by arranging a formed body of a heat-resistant foam material on the free end side of a metal plate member, arranging a thermistor element in the formed body, and entirely covering them with a Teflon film. A fixing device characterized by the above-mentioned. 3. The fixing device according to claim 1, wherein a metal plate is attached to a roller contact surface of the formed body. 4. A heat detecting device for detecting a roller surface temperature, wherein each of the temperature detecting members is in contact with a roller whose surface is coated with silicone rubber, and one of the rollers is provided with an applying member for applying a release agent. In the roller-type fixing device, the temperature detecting member in contact with the roller on which the application member is attached is provided with a formed body of a heat-resistant foam material on the free end side of a metal plate member, and in the formed body. A thermistor element is arranged, they are entirely covered with a Teflon film, and the other temperature detecting member is provided with a formed body of a heat-resistant foam material on a free end side of a metal plate member. A fixing device comprising a thermistor element arranged in a formed body, and a double-layered covering of an inner polyimide film and an outer Teflon film adhered to each other.