JP2000029351A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device that prevents the generation of scratches on the surface layer of a fixing roller or a pressure roller caused by the press contact of a temperature detection member or a temperature excessive-rise prevention member, correctly detects the temperature on the surface layer of the roller, and securely prevents an excessive rise in the temperature on the surface layer of the roller. SOLUTION: This fixing device is equipped with a fixing roller 1, a pressure roller 2 which is pressed to it, a temperature detection member 3 which detects the temperature of the fixing roller or the pressure roller and a cleaning web which cleans the surface of the fixing roller or pressure roller by bringing the web in contact with the surface. The temperature detection member detects the temperature of the fixing roller or pressure roller via the cleaning web.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a copying machine,
The present invention relates to a fixing device in an image forming apparatus such as a printer or a facsimile.

[0002]

2. Description of the Related Art FIG. 6 shows a color fixing device which is an example of a conventional fixing device of this type. The fixing device includes a fixing roller 1 and a pressure roller 2 pressed against the fixing roller. A temperature detecting member 3 having a thermistor for detecting the temperature of the fixing roller 1 or the pressure roller 2, an overheating preventing member 4 having a temperature fuse or a thermostat, and a fixing roller 1
Alternatively, there is provided a cleaning web 6 which comes into contact with the surface of the pressure roller 2 to clean it. Reference numerals 7 and 8 denote heaters provided on the fixing roller 1 or the pressure roller 2, reference numeral 9 denotes a pressing roller of the cleaning web 6, reference numeral 11 denotes a pressing spring of the pressing roller, reference numeral 12 denotes an oil application section, reference numeral 13 denotes a paper discharge roller, and reference numeral 14 denotes a winding roller. Each shows a spindle. In this example, the temperature detecting member 3 and the over-temperature preventing member 4 are provided at different positions in the circumferential direction of the fixing roller 1 or the pressing roller 2, but the over-temperature preventing member 4 and the temperature detecting member 4 are provided. 3 has a width smaller than the paper passing width.
Two different positions in the axial direction can also be provided.

In such a fixing device, a transfer paper carrying a toner image is carried into a nip portion between a fixing roller 1 and a pressure roller 2 and heated and pressed by these rollers 1 and 2. Then, the toner image is fixed on the transfer paper. At this time, the temperature of the fixing roller 1 or the pressure roller 2 is detected by the temperature detecting member 3, and a control program based on the detected temperature is used to control the surface of the fixing roller 1 or the pressure roller 2 so as to maintain the surface at a constant temperature. If the temperature control becomes impossible, the excessive temperature rise prevention member 4 prevents the temperature from rising excessively.

[0004] In the above-described apparatus, the fixing roller 1
Oil application section 12
As a result, oil is applied to the fixing roller 1. Incidentally, a so-called offset occurs in which a very small amount of toner adheres to the fixing roller 1 at the time of fixing at the nip portion. Therefore, the toner offset by the cleaning web 6 is removed from the fixing roller 1. The cleaning web 6 is usually a heat-resistant non-woven fabric having a thickness of several tens μm and is wound around a pressing roller 9, its tip is wound by a winding shaft 14, and is fixed by a pressing spring 11 via the pressing roller 9. The roller 14 is pressed by the roller 1, and at this time, the winding shaft 14 rotates by a very small amount.
The fresh web surface is always in contact with the fixing roller 1.

[0005]

In the above-mentioned color fixing device, since the surface layer of the fixing roller 1 and the pressure roller 2 is made of silicone rubber, if the surface layer is damaged, it is replaced by the toner. The temperature detecting member 3 is brought into contact with the surface layers of the fixing roller 1 and the pressure roller 2 in order to accurately detect the temperature. It is ideal that foreign matter such as powder is deposited and easily damages the surface layers of the fixing roller 1 and the pressure roller 2, and the overheat prevention member 4 is brought into contact with the surface layer of the fixing roller 1 and the pressure roller 2. However, in this case, there is a possibility that the same phenomenon as described above may occur. Therefore, the excessive temperature rise prevention member 4 cannot be brought into contact with the surface layers of the fixing roller 1 and the pressure roller 2 and is disposed in a non-contact state. You have to do something like this Et accurately be temperature controlled, and there is a problem that it is difficult to prevent overtemperature.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems of the conventional fixing device, and to prevent the surface layer of the fixing roller or the pressure roller from being damaged by the contact of the temperature detecting member or the over-temperature preventing member. It is an object of the present invention to provide a fixing device which does not occur, can accurately detect the temperature of the surface layer of the roller, and can reliably prevent the temperature of the surface layer of the roller from excessively rising.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a fixing roller, a pressing roller pressed against the fixing roller, and a temperature detecting temperature of the fixing roller or the pressing roller. In a fixing device provided with a detecting member and a cleaning web that abuts on the surface of the fixing roller or the pressure roller to clean the fixing roller, the invention according to claim 1 is configured such that the temperature detecting member is connected via the cleaning web. 3. The method according to claim 2, wherein a temperature of the fixing roller or the pressure roller is detected.
The temperature detection member is pressed against the cleaning web by a pressing member.

According to a third aspect of the present invention, there is provided a fixing roller,
A pressure roller pressed against the pressure roller, a member for preventing an excessive temperature rise of the fixing roller or the pressure roller, and a cleaning web for contacting and cleaning the surface of the fixing roller or the pressure roller. In the fixing device provided with the above, the overheating prevention member prevents the overheating of the fixing roller or the pressure roller via the cleaning web, and the invention according to claim 4, wherein the overheating prevention member is pressed. The cleaning web is pressed by the member.

The invention described in claim 5 is the invention according to claim 2 or 4
In the invention described in (1), the pressing member presses both ends of the temperature detecting member or the over-temperature preventing member.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention shown in FIGS. 1 to 5 will be described in detail with reference to the drawings. The description will be omitted, and different portions will be mainly described. Since the fixing roller 1 and the pressure roller 2 are the same, in each of the second and subsequent embodiments, only the fixing roller 1 will be described.
The description of is omitted.

FIG. 2 shows a temperature detecting member 3 according to a first embodiment of the present invention. In the first embodiment, a pressing roller 9 for pressing a cleaning web 6 against a fixing roller 1 is shown.
Are provided in a pair, and the temperature detecting member 3 is a thermistor 5 supported by a leaf spring 16 and a sponge 17 in this example.
And is disposed in the middle of the pressing roller 9 and contacts the cleaning web 6 to detect the temperature of the surface of the fixing roller 1. The sponge 17 supporting the temperature detecting member 3 is constituted by a heat-resistant sponge.

According to the first embodiment, when performing the fixing operation, since the temperature detecting member 3 is in contact with the cleaning web 6 and the cleaning web 6 is in contact with the fixing roller 1, the cleaning web 6 is fixed on one side. The offset toner on the surface of the roller 1 is cleaned, and the surface of the temperature detecting member 3 is cleaned on the other surface. Thereby, the temperature detecting member 3
Can be prevented from being removed and the surface of the fixing roller 1 from being damaged. However, since the surface of the temperature detecting member 3 abuts on the cleaning web 6, there is a temperature difference of 3 ° C. or less when the surface is directly in contact with the surface of the fixing roller 1. It can be said that there is no problem.

FIG. 3 shows a temperature detecting member 3 according to a second embodiment of the present invention. In the second embodiment, another example of the temperature detecting member 3 is used. A pressing spring 10 for directly pressing the cleaning web 6 against
Leaf spring indicating the temperature detecting member 3 in the first embodiment
16 and the pressing roller 9 for pressing the cleaning web 6 against the fixing roller 1 is removed, and instead of pressing the cleaning web 6 against the fixing roller 1 by the pressing roller 9, the cleaning web 6 is directly
The first embodiment is different from the first embodiment in that is is pressed.

FIG. 4 shows an overheating prevention member 4 according to a third embodiment of the present invention. In the third embodiment, an example of the overheating prevention member 4 is used and the first embodiment is used. In place of the temperature detecting member 3 in the form, an excessively high temperature preventing member 4 is provided.
Since the portion of the thermostat 15 that contacts the cleaning web 6 is formed of a metal plate, the thermostat 15 can easily contact the cleaning web 6 and efficiently receive the heat of the fixing roller 1. Therefore, it is necessary to increase the operating temperature, but there is an advantage in that it operates faster than the non-contact type in the event of an abnormality.

FIG. 5 shows an overheat prevention member 4 according to a fourth embodiment of the present invention. In the fourth embodiment, another example of the overheat prevention member 4 is used and a thermostat is used. Instead of being different from the third embodiment in that the thermal fuse 18 is incorporated in the sponge 17, the diameter of the fuse 18 is about 3 mm.

In each of the above embodiments, the temperature detecting member 3 and the overheating preventing member 4 are shown in two different types, respectively, but the combination is not specified. It goes without saying that any combination is selected as necessary.

[0017]

As described above, the present invention provides a fixing roller, a pressing roller pressed against the fixing roller, a temperature detecting member for detecting the temperature of the fixing roller or the pressing roller, a fixing roller or a heating roller. In a fixing device provided with a cleaning web for contacting and cleaning the surface of the pressure roller, the invention according to claim 1 is characterized in that the temperature detecting member has a temperature of the fixing roller or the pressure roller via the cleaning web. Is detected, the temperature detecting member can always clean its surface with the cleaning web, and there is an effect that damage to the fixing roller or the pressure roller is prevented.

According to the second aspect of the present invention, the temperature detecting member is pressed against the cleaning web by the pressing member. Therefore, in addition to the same effect as the first aspect of the present invention, a small space and a small number of parts are required. This has the effect of reducing the number of pixels.

According to a third aspect of the present invention, there is provided a fixing roller,
A pressure roller pressed against the pressure roller, a member for preventing an excessive temperature rise of the fixing roller or the pressure roller, and a cleaning web for contacting and cleaning the surface of the fixing roller or the pressure roller. In the fixing device provided with the above, the overheating prevention member prevents overheating of the fixing roller or the pressure roller via the cleaning web, so that the overheating prevention member always cleans its surface with the cleaning web. Therefore, it is possible to prevent the fixing roller or the pressure roller from being damaged.

According to the fourth aspect of the present invention, since the excessive temperature rise preventing member is pressed against the cleaning web by the pressing member, the same effect as that of the first aspect of the present invention is obtained. There is an effect that the number of parts can be reduced.

The invention described in claim 5 is the invention according to claim 2 or 4
In the invention described in the above, since the pressing member presses both ends of the temperature detecting member or the over-temperature preventing member, the temperature is accurately detected by the temperature detecting member, or the over-temperature preventing member surely prevents the over-heating. There is an effect that can be.

[Brief description of the drawings]

FIG. 1 is a front view of a first embodiment of the present invention.

FIG. 2 is a front view of a main part of the first embodiment.

FIG. 3 is a front view of a main part according to a second embodiment of the present invention.

FIG. 4 is a front view of a main part according to a third embodiment of the present invention.

FIG. 5 is a front view of a main part according to a fourth embodiment of the present invention.

FIG. 6 is a front view of an example of a conventional fixing device of the same type as the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Fixing roller 2 Pressure roller 3 Temperature detecting member 4 Overheat prevention member 5 Thermistor 6 Cleaning web 7 Heater 8 Heater 9 Press roller 10 Press spring 11 Press spring 12 Oil application section 13 Paper discharge roller 14 Winding shaft 15 Thermostat 16 Leaf spring 17 Sponge 18 Thermal fuse

Claims (5)

[Claims] A fixing roller, a pressing roller pressed against the fixing roller, a temperature detecting member for detecting a temperature of the fixing roller or the pressing roller, A fixing device provided with a cleaning web for cleaning, wherein the temperature detecting member detects the temperature of the fixing roller or the pressure roller via the cleaning web. 2. The fixing device according to claim 1, wherein the temperature detecting member is pressed against the cleaning web by a pressing member. 3. A fixing roller, a pressure roller pressed against the fixing roller, a member for preventing a temperature of the fixing roller or the pressure roller from rising excessively, and a member for contacting the surface of the fixing roller or the pressure roller. In a fixing device provided with a cleaning web for contacting and cleaning the fixing web, an overheating prevention member prevents an overheating of a fixing roller or a pressure roller via the cleaning web. . 4. The fixing device according to claim 3, wherein the overheating prevention member is pressed against the cleaning web by a pressing member. 5. The fixing device according to claim 2, wherein the pressing member presses both ends of the temperature detecting member or the over-temperature preventing member.