JPH11153923A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent, in case transfer paper is jammed, an uncontacted temperature sensor from being soiled by the jammed transfer paper between a fixing heat roller and the uncontacted temperature sensor, and from being damaged by force exerted to the uncontacted temperature sensor by the jammed transfer paper. SOLUTION: Between the fixing heat roller 1 and the uncontacted temperature sensor 3, a sensor protective member 4, having an opening 5 for receiving infrared rays from the fixing heat roller 1, is fixed. The uncontacted temperature sensor 3 is connected, via connectors (8a and 8b), to a temperature controller 14, for the control of the temperature of the fixing heat roller 1, which incorporates an amplifier 10, etc. The fixing heat roller 1 and the uncontacted temperature sensor 3 are so constituted as to take the form of a replaceable fixing unit 6, and the temperature controller 14 is disposed outside the fixing unit 6. The uncontacted temperature sensor 3 is composed of a bridge circuit having a thermister built in it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic copying machine,
The present invention relates to a fixing device in an image forming apparatus such as a laser beam printer, and more particularly, to a fixing device having a non-contact temperature sensor for controlling a fixing temperature of a fixing member for thermal fixing.

[0002]

2. Description of the Related Art As a technique for detecting a fixing temperature in a fixing device provided in an electrophotographic copying machine or the like in a non-contact state, for example, Japanese Utility Model Application Laid-Open No. Sho 60-125661 and Japanese Unexamined Patent Application Publication No.
There is one described in Japanese Patent No. 55680.

The former technique is a temperature detecting device for a heating roller provided with a non-contact temperature sensor near a heating roller (fixing heat roller) of a fixing device for detecting a peripheral surface temperature of the roller in a non-contact state. A non-contact temperature sensor is provided with a cylindrical portion having a slit to restrict the temperature detection visual field to only the fixing heat roller.

In the latter technique, a non-contact temperature sensor disposed in the vicinity of a heating roller (fixing heat roller) of a fixing device for performing temperature control and detecting a peripheral surface temperature of the roller in a non-contact state is heated. The roller (fixing heat roller) is provided so as to be able to be directed from the end to the center of the roller, and detects the peripheral surface temperature of the heating roller (fixing heat roller).

[0005]

However, in the former technique, although the purpose is different from that of the present invention, the cylindrical portion is attached to the non-contact temperature sensor between the fixing heat roller and the non-contact temperature sensor. Therefore, when the transfer paper is jammed, the force of the jammed transfer paper is applied to the non-contact temperature sensor, and the non-contact temperature sensor may be damaged.

In the latter technique, the non-contact temperature sensor is rotated in the axial direction of the fixing heat roller, and it is impossible to prevent the non-contact temperature sensor from being stained or damaged.

Further, thermopiles which have been used as one of the non-contact temperature sensors are expensive, and even if the non-contact temperature sensor becomes dirty, it cannot be replaced. Was needed.

The present invention has been made in view of the above points, and an object of the present invention is to provide a sensor fixing member between a fixing member for heat fixing and a non-contact temperature sensor. Accordingly, it is possible to prevent the non-contact temperature sensor from being stained or damaged by the jammed transfer paper.

An object of the present invention is that the sensor protection member has an opening for receiving infrared rays from the heat fixing fixing member, so that the sensor protection member does not block the infrared rays from the heat fixing fixing member. Is to do so.

[0010] An object of the invention according to claim 3 is to make the size of the opening of the sensor protection member larger than the size of the substantial infrared receiving surface of the non-contact temperature sensor.
The purpose is to eliminate the influence of the sensor protection member.

The object of the invention described in claim 4 is that, in addition to the object of the invention described in claim 1, 2, or 3, the non-contact temperature sensor is separated from the fixing member with respect to its own mounting position. And the mounting position, so that the jammed transfer paper may be bent and cornered by mistake from the opening or between the sensor protection member and the non-contact temperature sensor. It is an object of the present invention to surely prevent the non-contact temperature sensor from being stained or damaged by the jammed transfer paper even in the case of intrusion.

It is another object of the present invention to provide a non-contact temperature sensor that is configured to be displaceable between a mounting position and a separation position where the non-contact temperature sensor is separated from a fixing member. An object of the present invention is to prevent the non-contact temperature sensor from being damaged by the applied transfer paper due to the force applied thereto.

[0013] The object of the invention according to claim 6 is, in addition to the object of the invention according to any one of claims 1 to 5, to obtain a non-contact temperature sensor with good sensitivity, quick response and low cost. It is in.

A seventh object of the present invention is to provide a fixing device unit in which a heat fixing member and a non-contact temperature sensor can be exchanged in addition to the object of any one of the first to sixth inventions. Accordingly, it is an object of the present invention to provide a fixing device which can be replaced with a non-contact temperature sensor when the fixing device unit is replaced, so that a new non-contact temperature sensor free from dirt or the like can be obtained.

An object of the present invention is that the fixing member for heat fixing and the non-contact temperature sensor are configured in a replaceable fixing device unit, so that the non-contact temperature sensor is also replaced when the fixing device unit is replaced. Accordingly, it is an object of the present invention to provide a fixing device that can be used as a new non-contact temperature sensor free from dirt and the like.

A further object of the present invention is to provide a non-contact temperature sensor having good sensitivity, quick response, and low cost, in addition to the object of the eighth invention.

An object of the invention according to claim 10 is to realize the object of the invention according to any one of claims 1 to 9 in a fixing device in which the fixing member for heat fixing is a heat roller for heat fixing. It is in.

According to an eleventh aspect of the present invention, there is provided a fixing device in which the fixing member for thermal fixing is a heat belt for thermal fixing, and the object of the invention according to any one of claims 1 to 9 is realized. It is in.

[0019]

In order to achieve the above-mentioned object, according to the first aspect of the present invention, there is provided a fixing member for thermal fixing, and a peripheral temperature of the fixing member disposed near the fixing member. In a fixing device including a non-contact temperature sensor that detects a contact state, a sensor protection member is provided between the fixing member and the non-contact temperature sensor.

According to a second aspect of the present invention, in the fixing device of the first aspect, the sensor protection member has an opening for receiving infrared rays from the fixing member.

According to a third aspect of the present invention, in the fixing device according to the second aspect, the size of the opening is equal to or larger than a size of a substantial infrared receiving surface of the non-contact temperature sensor. I do.

According to a fourth aspect of the present invention, in the fixing device according to the first, second or third aspect, the non-contact temperature sensor is arranged such that the non-contact temperature sensor is separated from the fixing position by a separation position separated from the fixing member. And a displacement means for displacing the non-contact temperature sensor between the separated position and the mounting position.

According to a fifth aspect of the present invention, there is provided a fixing device having a fixing member for heat fixing, and a non-contact temperature sensor disposed near the fixing member and detecting a peripheral surface temperature of the fixing member in a non-contact state. The non-contact temperature sensor is freely displaceable relative to its own mounting position between a separation position separated from the fixing member and the mounting position, and the non-contact temperature sensor is mounted on the separated position and the mounting position. It has a displacing means for displacing between the position.

The invention according to claim 6 is the invention according to claims 1 to 5
Wherein the non-contact temperature sensor comprises a thermistor assembled into a bridge circuit.

The invention according to claim 7 is the invention according to claims 1 to 6
In the fixing device according to any one of the above, the non-contact temperature sensor is connected to a temperature control device including an amplification unit for performing temperature control of the fixing member via a connector, and the fixing member and The non-contact temperature sensor is configured as a replaceable fixing device unit, and the amplifying unit and the temperature control device are disposed outside the fixing device unit.

The invention according to claim 8 is a fixing device having a fixing member for heat fixing and a non-contact temperature sensor disposed near the fixing member and detecting a peripheral surface temperature of the fixing member in a non-contact state. Wherein the non-contact temperature sensor is connected via a connector to a temperature control device including an amplifier for controlling the temperature of the fixing member, and the fixing device is capable of exchanging the fixing member and the non-contact temperature sensor. The amplifying unit and the temperature control device are disposed outside the fixing device unit.

According to a ninth aspect of the present invention, in the fixing device according to the eighth aspect, the non-contact temperature sensor comprises a thermistor assembled in a bridge circuit.

According to a tenth aspect of the present invention, in the fixing device according to any one of the first to ninth aspects, the fixing member is a heat roller for heat fixing.

According to an eleventh aspect of the present invention, in the fixing device according to any one of the first to ninth aspects, the fixing member is a heat belt for heat fixing.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention including embodiments of the present invention (hereinafter, simply referred to as "embodiments") will be described below in detail with reference to the drawings. Throughout each embodiment, for components and elements having the same function, shape, and the like,
The description is omitted by attaching the same reference numerals. (Embodiment 1) FIG. 1 shows Embodiment 1 of the present invention. In FIG. 1, reference numeral 6 denotes a fixing device unit of the present invention (hereinafter, simply referred to as “fixing unit”), and reference numeral 14 denotes a temperature control device of the present invention. The fixing device according to the first embodiment is mounted on, for example, an electrophotographic copying machine. As shown in FIG.
And a temperature control device 14 (see claim 1, claim 2, claim 3, claim 6, and claim 10).

As shown in FIGS. 1 and 2, the fixing unit 6 includes a heat fixing heat roller 1 (hereinafter, referred to as "fixing heat roller 1") as a heat fixing fixing member, a pressure roller 16, It mainly comprises a temperature sensor 3, a sensor protection member 4, a guide plate 20, a unit cover 7, and a socket 8a.

The fixing heat roller 1 has a function of heating and fusing an unfixed toner image on the transfer paper P. The fixing heat roller 1 has a built-in heater 2 as a heat source therefor. As the heater 2, for example, a halogen lamp or a Colts lamp is used. Fixing heat roller 1
Is a drive roller rotated by a rotation drive means such as a motor (not shown).

The pressure roller 16 is pressed against the fixing heat roller 1 and is driven to rotate, thereby conveying the transfer paper P through a fixing nip formed between the pressure roller 16 and the fixing heat roller 1.
At both ends of the shaft of the pressure roller 16, a pressure spring (not shown) is provided via a bearing member (not shown). The pressure spring causes the pressure roller 16 to press against the fixing heat roller 1. Has been energized.

Fixing heat roller 1 and pressure roller 16
For example, a material in which a heat-resistant elastic member layer made of silicone rubber or the like is provided on a cored bar is used.

Fixing heat roller 1 and pressure roller 16
A guide plate 20 for guiding the transfer of the transfer paper P to the fixing nip portion is provided on the downstream side in the transfer paper transport direction.

The non-contact temperature sensor 3 is disposed near the fixing heat roller 1 and detects the peripheral surface temperature of the fixing heat roller 1 in a non-contact state. Non-contact temperature sensor 3
Speaking of an embodiment, is disposed at a position separated from the outer peripheral surface of the fixing heat roller 1 by a distance L of about 7 mm, and is fixed to the unit cover 7 via a bracket (not shown).

As the non-contact temperature sensor 3, it is preferable to use a thermistor in terms of good sensitivity, quick response, and low cost. In particular, four thermistors TH1 to TH4 as shown in FIG. It is good to use what was assembled in the circuit. More specifically, the non-contact temperature sensor 3 is a MAB (Mic) manufactured by Ishizuka Electronics Co., Ltd.
ro Air Bridge). This MAB
Then, the infrared rays 15 from the fixing heat roller 1 enter the thermistors TH1 and TH4, and the thermistors TH1 and TH4.
2 and the thermistor TH3 are covered with an infrared reflecting film so as to reflect the infrared light 15. The thermistor TH1 and the thermistor TH4 form an infrared input part. In FIG. 3, reference symbol Vcc denotes a power supply voltage supplied to the bridge circuit, and the peripheral voltage of the fixing heat roller 1 is detected and measured by measuring the output voltage (or current) output from the bridge circuit. be able to.

Thermistor TH1 and TH4
The sensor protection member 4 is attached so that the infrared input portion of the sensor does not become dirty and the infrared reflection films of the thermistors TH2 and TH3 are not damaged.

The sensor protection member 4 includes the fixing heat roller 1
And the non-contact temperature sensor 3, and is fixed to the unit cover 7 via a bracket (not shown). The sensor protection member 4 is made of, for example, a plate member such as a sheet metal, and has a function of preventing the jammed transfer sheet P from staining or damaging the non-contact temperature sensor 3.
An opening 5 for receiving infrared rays from the fixing heat roller 1 is opened in the sensor protection member 4. The size of the opening 5 is set to at least a size that does not block the infrared rays 15 to the infrared input portion of the thermistor TH1 and the thermistor TH4, in other words, is equal to or larger than a size of a substantial infrared receiving surface of the non-contact temperature sensor 3. ing. In order to reduce the variation of related components and the influence of the sensor protection member 4, it is desirable to provide the opening 5 larger than the shape of the non-contact temperature sensor 3.

The unit cover 7 is made of a synthetic resin or the like appropriately reinforced by sheet metal or the like, and is divided and opened and closed at an appropriate portion so that the jammed transfer paper P can be processed, maintained, cleaned, or the like. It is freely configured. On the outer wall of the unit cover 7, a socket 8a constituting the connector of the present invention is attached. In the socket 8a, connection terminals such as a power supply line to the heater 2, a lead wire on the heater 2 side for connecting to a lead wire from the SSR 13 described later, and an electric wire connected to the non-contact temperature sensor 3 are gathered. .

The temperature control device 14 includes an amplifying unit 10, an A / D
It mainly comprises an (analog / digital) converter 11, a temperature control unit 12, an SSR (solid state relay) 13, and a jack 8b.

The temperature controller 14 controls the peripheral surface temperature of the fixing heat roller 1 via the heater 2. Amplifier 1
Numeral 0 includes an amplifier such as an operational amplifier circuit and amplifies an output voltage value as a detection result of the peripheral surface temperature of the fixing heat roller 1 detected by the non-contact temperature sensor 3. A / D converter 1
1 (simply shown as A / D only in FIG. 1) converts the analog amount of the output voltage amplified by the amplifier 10 into a digital amount. The temperature control unit 12 includes, for example, a microcomputer and a control circuit including a transistor circuit. The temperature control unit 12 sets the output voltage value (the peripheral surface temperature of the fixing heat roller 1) of the digital non-contact temperature sensor 3 converted by the A / D converter 11 to a predetermined temperature range of the fixing heat roller 1. By turning on / off the SSR (solid state relay) 13 as appropriate, a necessary current from the power supply (not shown) to the heater 2 may be supplied so as to be within the set temperature range of the fixing heat roller 1. That is, the so-called feedback control for controlling the peripheral surface temperature of the fixing heat roller 1 by cutting is performed.

The jack 8b constitutes the connector of the present invention, and the jack 8b has terminals and the like connected to the lead wire to the amplifier 10 and the lead wire from the SSR 13, respectively.

As described above, in the first embodiment, the non-contact temperature sensor 3 includes the amplifying unit 10 for controlling the temperature of the peripheral surface of the fixing heat roller 1 via the connector including the socket 8a and the jack 8b. Temperature control device 14
Are connected to the fixing heat roller 1 and the pressure roller 1
6, the sensor protection member 4, the non-contact temperature sensor 3 and the like are configured in a replaceable fixing unit 6, and the jack 8b and the temperature control device 14 are arranged outside the fixing unit 6. Accordingly, when the fixing unit 6 is replaced, the jack 8b connected to the amplifying unit 10 is removed from the socket 8a on the side of the fixing unit 6 connected to the non-contact temperature sensor 3, whereby the fixing unit 6 is removed.
-Side non-contact temperature sensor 3 and amplifying section 10 on the fixing device main body side
The fixing unit 6 including the non-contact temperature sensor 3 and the like can be replaced.

Next, the operation will be briefly described. In the above configuration, first, a toner image is formed on the transfer paper P through a charging, exposure, development, and transfer process (not shown), and the transfer paper P on which the toner image is formed is formed on the guide plate 20. It is conveyed to the fixing process while being guided.
At this time, when the transfer paper P is jammed in the fixing nip portion between the fixing heat roller 1 and the pressure roller 16 or the like,
Since the sensor protection member 4 is disposed as described above,
The non-contact temperature sensor 3 can be prevented from being stained or damaged by the jammed transfer paper P.

When the fixing unit 6 is replaced, the fixing heat roller 1 and the pressure roller 16 are judged to have reached the end of their life due to thermomechanical fatigue and the like, and the non-contact temperature sensor 3 is also used. Since the dirt and scratches are increasing, by removing the jack 8b from the socket 8a of the connector and replacing the entire fixing unit 6, the non-contact temperature sensor 3 is also replaced together, and the new fixing unit 6 is fixed. By mounting the sensor on the apparatus body side, the sensor can be replaced with a new non-contact temperature sensor 3 free from dirt and the like.

(Embodiment 2) FIG. 4 shows Embodiment 2 of the present invention. The second embodiment differs from the first embodiment shown in FIGS. 1 to 3 in that the sensor protection member 4 is removed and the non-contact temperature sensor 3 is separated from the fixing heat roller 1 with respect to its own mounting position. To be displaceable between the separated position and the mounting position, and the non-contact temperature sensor 3
The main difference lies in that there is a displacement means for displacing the position between the separation position and the mounting position (see claims 5, 6, 7, and 10). The illustration of the unit cover 7, the temperature control device 14, and the like shown in FIG. 1 are omitted in FIG.

The non-contact temperature sensor 3 is mounted and fixed on the free end side of the movable member 17. The movable member 17 is made of, for example, a sheet metal, is bent into an L-shape on the back side of the paper surface, and has a base end screwed to the unit cover 7 (not shown in FIG. 4). To be rotatable. A torsion coil spring 19 is wound around the pin screw 26. One end of the torsion coil spring 19 is locked on the unit cover 7 side, and the other end is locked on the movable member 17, so as to always provide the swinging behavior in the direction approaching the fixing heat roller 1 (clockwise in FIG. 4). Have been. The biasing force of the torsion coil spring 19 causes the non-contact temperature sensor 3 and the movable member 17 to occupy a separated position where the non-contact temperature sensor 3 and the movable member 17 escape from the fixing heat roller 1 and separate from the fixing position due to the force of the jammed transfer sheet P. And
It is set within an appropriate range that does not damage the non-contact temperature sensor 3 as much as possible.

The movable member 17 is held at a position at the same distance as that of the first embodiment, that is, at its own mounting position, by a stopper 18 implanted in the unit cover 7. As described above, the displacement means mainly includes the movable member 17, the torsion coil spring 19, the pin screw 26, and the stopper 18.

If the transfer sheet P is jammed during the operation of the fixing device, the jammed transfer sheet P may push the non-contact temperature sensor 3 strongly. The movable member 3 and the movable member 17 oscillate in a direction (counterclockwise in FIG. 4) to escape from the fixing heat roller 1 against the urging force of the torsion coil spring 19 and occupy the separated position. Therefore, it is possible to prevent the non-contact temperature sensor 3 from being damaged by the jammed transfer paper.

The displacing means may be composed of the above-mentioned components, or may be a compression coil spring 25 as shown in FIG. 6 instead of the torsion coil spring 19. In this case, the compression coil spring 25 is interposed between the inner wall of the unit cover 7 and the movable member 17 and always provides the swinging behavior in the direction approaching the fixing heat roller 1 (clockwise in FIG. 4). is there.

If it is desired to prevent contamination of the non-contact temperature sensor 3 as in the first embodiment, a sensor protection member is provided between the fixing heat roller 1 and the non-contact temperature sensor 3 as in the first embodiment. 4 may be fixedly provided, or the sensor protection member 4 may be integrally fixed to the movable member 17 so as to swing together with the non-contact temperature sensor 3 and the movable member 17. (Refer to claim 1, claim 2, claim 3, claim 4, claim 6, claim 7, and claim 10).

Further, if the non-contact temperature sensor 3 can be tolerated to some extent until the fixing unit 6 is replaced (for example, when the non-contact temperature sensor 3 can be cleaned). It can be said that the configuration may be such that the sensor protection member 4 is removed from FIG. 1 (see claims 8, 9, and 10).

(Third Embodiment) FIG. 7 shows a third embodiment of the present invention. The third embodiment is different from the first embodiment shown in FIGS. 1 to 3 in that the unit cover 7 for forming the fixing unit 6 and the connector are removed and the fixing unit cannot be replaced. This is mainly different (see claim 1, claim 2, claim 3, claim 6, and claim 10).

In the third embodiment, the non-contact temperature sensor 3
It is preferable to use a thermistor or a combination of these in a bridge circuit in terms of good sensitivity, quick response, and low cost, but if this is not required, for example, use a radiation thermometer. Of course, a non-contact temperature sensor such as a thermopile may be used.

According to the third embodiment, when the transfer paper P is jammed in the fixing nip portion between the fixing heat roller 1 and the pressure roller 16, the sensor protection member 4 is provided as described above. Therefore, the non-contact temperature sensor 3 can be prevented from being stained or damaged by the jammed transfer paper P.

(Embodiment 4) Embodiment 4 of the present invention will be described with reference to FIG. This embodiment 4 is different from the embodiment 3 shown in FIG. 7 in that the sensor protection member 4 is removed and the non-contact temperature sensor 3 is attached to its own mounting position.
The main differences are that the fixing heat roller 1 is configured to be freely displaceable between a separation position and a mounting position, and that the non-contact temperature sensor 3 is provided with a displacing means for displacing the non-contact temperature sensor 3 between the separation position and the mounting position. (Refer to claim 5, claim 6, and claim 10). Temperature control device 14 shown in FIG.
And the like are omitted in FIG.

The non-contact temperature sensor 3 is mounted and fixed on the free end side of the movable member 17. The movable member 17 is made of, for example, sheet metal, is bent in an L-shape on the back side of the paper surface, and its base end is rotatably supported by a pin screw 26 screwed to the fixing device main body side plate. I have. A torsion coil spring 19 is wound around the pin screw 26. One end of the torsion coil spring 19 is locked to the fixing device main body side plate side, and the other end is locked to the movable member 17, so that the swinging behavior of the torsion coil spring 19 always approaches the fixing heat roller 1 (clockwise in FIG. 4). Has been given. The biasing force of the torsion coil spring 19 causes the non-contact temperature sensor 3 and the movable member 17 to occupy a separated position where the non-contact temperature sensor 3 and the movable member 17 escape from the fixing heat roller 1 and separate from the fixing position due to the force of the jammed transfer sheet P. Is set in an appropriate range.

The movable member 17 is held at a position at the same distance as in the first and third embodiments, that is, at its own mounting position, by a stopper 18 implanted in the fixing device main body side plate. As described above, the displacement means mainly includes the movable member 17, the torsion coil spring 19, the pin screw 26, and the stopper 18.

If the transfer paper P is jammed during the operation of the fixing device, the jammed transfer paper P may push the non-contact temperature sensor 3 strongly. The movable member 3 and the movable member 17 oscillate in a direction (counterclockwise in FIG. 4) to escape from the fixing heat roller 1 against the urging force of the torsion coil spring 19 and occupy the separated position. Therefore, it is possible to prevent the non-contact temperature sensor 3 from being damaged by the jammed transfer paper.

If it is desired to prevent contamination of the non-contact temperature sensor 3 as in the third embodiment, a sensor protection member is provided between the fixing heat roller 1 and the non-contact temperature sensor 3 as in the third embodiment. 4 may be fixedly provided, or the sensor protection member 4 may be integrally fixed to the movable member 17 so as to swing together with the non-contact temperature sensor 3 and the movable member 17. (Refer to claim 1, claim 2, claim 3, claim 4, claim 6, and claim 10).

(Fifth Embodiment) FIG. 5 shows a fifth embodiment of the present invention. In FIG. 1, reference numeral 36 denotes a fixing device unit of the present invention (hereinafter, simply referred to as “fixing unit”). The fixing device according to the fifth embodiment is mounted on, for example, an electrophotographic copying machine, and includes a fixing unit 36 and a temperature controller 14 as shown in FIG.

The fifth embodiment is different from the first embodiment in that
Instead of the fixing unit 6 including the fixing heat roller 1 as a fixing member for heat fixing, a heat belt 23 for heat fixing (hereinafter, referred to as “fixing heat belt 23”) as a fixing member for heat fixing is provided. The main difference is that the fixing unit 36 is provided (see claim 1, claim 2, claim 3, claim 6, claim 7, and claim 11).

The following description focuses on the differences. The fixing unit 36 includes a fixing roller 21, a heating roller 22, an endless fixing heat belt 23 stretched between the fixing roller 21 and the heating roller 22, and a fixing heat belt 23 provided inside the heating roller 22. Heater 2, pressure roller 24 provided opposite to fixing roller 21, non-contact temperature sensor 3, sensor protection member 4, unit cover 7
And a socket 8a.

As the fixing roller 21, a roller provided with a heat-resistant elastic member layer made of, for example, silicone sponge rubber or solid silicone rubber on a metal core is used.

The heating roller 22 may have any structure as long as it has the heater 2 therein and can supply an appropriate amount of heat to the fixing heat belt 23. Heater 2
Comprises, for example, a halogen lamp. In addition, the heater 2 for heating the fixing heat belt 23 is not limited to the configuration disposed inside the heating roller 22 as described above. It may be arranged inside each. In each of the embodiments described below, the heater 2 will be described as being disposed inside the heating roller 22. Heating roller 22
A pair of pressure springs (not shown) for stretching the fixing heat belt 23 with a predetermined tension are provided at both ends of the shaft portion.

The fixing heat belt 23 has a function of heating and fixing an unfixed toner image on the transfer paper P by heat.
Any known means capable of supplying thermal energy corresponding to a fixed range of fixing temperature to the above unfixed toner may be used.

As the pressure roller 24, a roller in which a heat-resistant elastic member layer made of solid silicone rubber such as silicone sponge rubber is provided on a cored bar is used. At both ends of the shaft of the pressure roller 24, a pair of pressure springs (not shown) for pressing the pressure roller 24 against the fixing roller 21 with a predetermined urging force are provided. The pressure roller 24 is urged by the pressure spring in a direction in which the pressure roller 24 comes into pressure contact with the fixing roller 21 via the fixing heat belt 23.

In such a fixing device using the fixing heat belt 23 system, the fixing roller 21 is usually set as a driving roller and the heating roller 22 is set as a driven roller. However, the present invention is not limited to this. Depending on the purpose and application, the heating roller 22 side is used as a driving roller, and the fixing roller 2
The one side may be a driven roller.

The non-contact temperature sensor 3 is arranged near the fixing heat belt 23 wound around the heating roller 22 and detects the peripheral surface temperature of the fixing heat belt 23 in a non-contact state. The non-contact temperature sensor 3 is disposed at a position separated from the outer peripheral surface of the fixing heat belt 23 by a distance L of about 7 mm, and
And is fixed to the unit cover 7 via the.

As the non-contact temperature sensor 3, the first embodiment
It is preferable to use a thermistor for the same reason as
In particular, four thermistors TH1 to TH1 as shown in FIG.
It is preferable to use one in which TH4 is assembled in a bridge circuit. More specifically, the non-contact temperature sensor 3 is a MAB (Micro Air Bridge) manufactured by Ishizuka Electronics Co., Ltd.
e) is used. The infrared input portions of the thermistor TH1 and the thermistor TH4 become dirty or the thermistor TH2
In addition, a sensor protection member 4 is provided so that the infrared reflection film of the thermistor TH3 is not damaged.

The sensor protection member 4 is a fixing heat belt 2
3 and is disposed between the non-contact temperature sensor 3 and fixed to the unit cover 7. The temperature control device 14
The temperature of the peripheral surface of the fixing heat belt 23 is controlled via the heater 2 and the heating roller 22.

As described above, in the fifth embodiment, the non-contact temperature sensor 3 includes the amplifying unit 10 for controlling the temperature of the peripheral surface of the fixing heat belt 23 via the connector including the socket 8a and the jack 8b. Temperature control device 1
4, the fixing roller 21 and the heating roller 2
2, the fixing heat belt 23, the pressure roller 24, the non-contact temperature sensor 3, the sensor protection member 4, the unit cover 7, the socket 8a, and the like are configured in a replaceable fixing unit 36, and the jack 8b and the temperature control device 14 are fixed. It is characterized in that it is arranged outside the unit 36.

When the fixing unit 36 is replaced, the jack 8b connected to the amplifier 10 is removed from the socket 8a on the side of the fixing unit 36 connected to the non-contact temperature sensor 3, so that the fixing unit 36 is removed.
-Side non-contact temperature sensor 3 and amplifying section 10 on the fixing device main body side
The fixing unit 36 including the non-contact temperature sensor 3 and the like can be replaced.

Next, the operation will be briefly described. In the above configuration, first, a toner image is formed on the transfer paper P through a charging, exposure, development, and transfer process (not shown), and the transfer paper P on which the toner image is formed is transferred to the guide plate 20 ( It is not shown in FIG. 5, but is transported to the fixing step while being guided by FIG. 6). At this time, when the transfer paper P is jammed at a fixing nip portion between the fixing heat belt 23 and the pressure roller 24 of the fixing roller 21 and the like,
Since the sensor protection member 4 is disposed as described above,
The non-contact temperature sensor 3 can be prevented from being stained or damaged by the jammed transfer paper P.

When the fixing unit 36 is replaced, the fixing roller 21, the heating roller 22, the fixing heat belt 23, and the pressure roller 24 are judged to have reached the end of their life due to thermal mechanical fatigue and the like. In both cases, since the non-contact temperature sensor 3 has also increased in dirt and scratches, by removing the jack 8b from the socket 8a of the connector and replacing it with the fixing unit 36, the non-contact temperature sensor 3 is also replaced together. And the new fixing unit 36
Can be replaced with a new non-contact temperature sensor 3 free from dirt and the like by mounting the fixing device on the fixing device main body side.

(Embodiment 6) FIG. 6 shows Embodiment 6 of the present invention. The sixth embodiment is different from the fifth embodiment shown in FIG.
In contrast, the sensor protection member 4 is removed, and the non-contact temperature sensor 3 is configured to be displaceable with respect to its own mounting position between a mounting position separated from the fixing heat belt 23 and a mounting position. The main difference lies in that there is a displacement means for displacing the non-contact temperature sensor 3 between the separated position and the mounting position (see claims 5, 6, 7, and 11). Unit cover 7 shown in FIG.
The illustration of the temperature control device 14 and the like are all omitted in FIG.

The non-contact temperature sensor 3 is mounted and fixed on the free end side of the movable member 17. The movable member 17 is made of, for example, a sheet metal, and is bent in an L-shape on the back side of the drawing. The movable member 17 is rotatably supported at its base end by a pin screw 26 screwed to the unit cover 7 (not shown in FIG. 4). A compression coil spring 25 is interposed between the inner wall of the unit cover 7 and the movable member 17, and the non-contact temperature sensor 3 always approaches the fixing heat belt 23 by the urging force of the compression coil spring 25 (see FIG. In FIG. 6, a clockwise swinging behavior is given. The urging force of the compression coil spring 25 is applied to the non-contact temperature sensor 3 and the movable member 17 by the force of the jammed transfer paper P.
Is set in an appropriate range so as to occupy a separated position where the non-contact temperature sensor 3 escapes from the fixing heat belt 23 with respect to its own mounting position and is separated from the fixing heat belt 23 as much as possible.

The movable member 17 is held at a position at the same distance as in the fifth embodiment, that is, at its own mounting position, by a stopper 18 implanted in the unit cover 7. As described above, the displacement means mainly includes the movable member 17, the compression coil spring 25, the pin screw 26, and the stopper 18.

If the transfer sheet P is jammed during the operation of the fixing device, the jammed transfer sheet P may push the non-contact temperature sensor 3 strongly. The movable member 3 and the movable member 17 oscillate in a direction (counterclockwise in FIG. 6) to escape from the fixing heat belt 23 against the urging force of the compression coil spring 25 to occupy the separated position. Therefore, it is possible to prevent the non-contact temperature sensor 3 from being damaged by the jammed transfer paper.

As the displacement means, in addition to the above-mentioned components, the torsion coil spring 19 as shown in FIG. 4 may be used instead of removing the compression coil spring 25.

As in the fifth embodiment, if it is desired to prevent contamination of the non-contact temperature sensor 3 as well, a sensor protection member is provided between the fixing heat belt 23 and the non-contact temperature sensor 3 as in the fifth embodiment. 4 may be fixedly provided, or the sensor protection member 4 may be integrally fixed to the movable member 17 so as to swing together with the non-contact temperature sensor 3 and the movable member 17. (Claim 1, Claim 2,
(See Claims 3, 4, 7, and 11).

Further, if the non-contact temperature sensor 3 can be tolerated to some extent until the fixing unit 36 is replaced (for example, when the non-contact temperature sensor 3 can be cleaned). 5, it can be said that the sensor protection member 4 is removed (see claims 8, 9, and 11).

(Seventh Embodiment) FIG. 8 shows a seventh embodiment of the present invention. The seventh embodiment is different from the fifth embodiment shown in FIG.
The main difference is that the unit cover 7 for forming the fixing unit 36 and the connector are removed so that the entire fixing unit cannot be replaced (claims 1, 2, and 3). 3, claim 6, claim 1
1).

In the seventh embodiment, the non-contact temperature sensor 3
It is preferable to use a thermistor or a combination of these in a bridge circuit in terms of good sensitivity, quick response, and low cost, but if this is not required, for example, use a radiation thermometer. Of course, a non-contact temperature sensor such as a thermopile may be used.

According to the seventh embodiment, the transfer paper P is fixed to the fixing heat belt 23 of the fixing roller 21 and the pressing roller 24.
In the case where a jam occurs in the fixing nip portion or the like, since the sensor protection member 4 is disposed as described above, the non-contact temperature sensor 3 is stained by the jammed transfer paper P,
It can be prevented from being damaged.

(Eighth Embodiment) An eighth embodiment of the present invention will be described with reference to FIG. This embodiment 8 is different from the embodiment 7 shown in FIG. 8 in that the sensor protection member 4 is removed and the non-contact temperature sensor 3 is attached to its own mounting position.
The main difference is that the fixing heat belt 23 is configured so that it can be displaced between a separation position and a mounting position, and that the non-contact temperature sensor 3 has a displacing means for displacing the non-contact temperature sensor 3 between the separation position and the mounting position. (Refer to claim 5, claim 6, and claim 11).

The non-contact temperature sensor 3 is mounted and fixed on the free end side of the movable member 17. The movable member 17 has a base end rotatably supported by a pin screw 26 screwed to a fixing device main body side plate (not shown). A compression coil spring 25 is interposed between the inner wall of the fixing device main body side plate and the movable member 17, and the non-contact temperature sensor 3 always approaches the fixing heat belt 23 by the urging force of the compression coil spring 25. (Clockwise in FIG. 6).

The movable member 17 is held at a position at the same distance as that of the fifth embodiment, that is, at its own mounting position, by a stopper 18 implanted in the fixing device main body side plate.

When the transfer paper P is jammed during the operation of the fixing device, the jammed transfer paper P may push the non-contact temperature sensor 3 strongly. The movable member 3 and the movable member 17 oscillate in a direction (counterclockwise in FIG. 6) to escape from the fixing heat belt 23 against the urging force of the compression coil spring 25 to occupy the separated position. Therefore, it is possible to prevent the non-contact temperature sensor 3 from being damaged by the jammed transfer paper.

If it is desired to prevent contamination of the non-contact temperature sensor 3 as in the fifth embodiment, a sensor protection member is provided between the fixing heat belt 23 and the non-contact temperature sensor 3 as in the fifth embodiment. 4 may be fixedly provided, or the sensor protection member 4 may be integrally fixed to the movable member 17 so as to swing together with the non-contact temperature sensor 3 and the movable member 17. (Claim 1, Claim 2,
(See Claims 3, 4, 6, and 11).

In each of the above embodiments having the fixing unit 6 or 36, the non-contact temperature sensor 3 has been described as being mounted in the unit cover 7. However, the present invention is not limited to this. Alternatively, the unit cover 7 may be replaced together with the unit cover 7. For example, a hole may be formed in the unit cover 7 and the unit cover 7 may be mounted outside the unit cover 7.

In each of the above-described embodiments, it is preferable to use a thermistor or a combination of these elements in a bridge circuit because the non-contact temperature sensor 3 has good sensitivity, quick response, and low cost. If this is not required, and if the non-contact temperature sensor can be cleaned, a non-contact temperature sensor such as a radiation thermometer may be used. In this case, it goes without saying that the cleaning cycle of the non-contact temperature sensor such as a thermopile differs depending on the presence or absence of the sensor protection member 4, the presence or absence of the displacement means, or a combination thereof.

As described above, the present invention has been described with reference to the specific embodiments and the like. However, the configuration of the present invention is not limited to the above-described embodiments and the like, and may be configured by appropriately combining these. It will be apparent to those skilled in the art that various embodiments and examples can be configured according to the necessity, purpose, application, and the like within the scope of the present invention.

[0095]

As described above, according to the first aspect of the present invention, since the sensor protection member is provided between the fixing member for thermal fixing and the non-contact temperature sensor, the non-contact temperature can be reduced by the jammed transfer paper. It is possible to prevent the contact temperature sensor from becoming dirty or damaged.

According to the second aspect of the present invention, since the sensor protection member has the opening for receiving the infrared rays from the heat fixing fixing member, the sensor protection member does not block the infrared rays from the heat fixing fixing member. You can do so.

According to the third aspect of the present invention, the size of the opening of the sensor protection member is made larger than the size of the substantial infrared receiving surface of the non-contact temperature sensor, thereby eliminating the influence of the sensor protection member. be able to.

According to the fourth aspect of the present invention, the non-contact temperature sensor is configured to be displaceable with respect to its own mounting position between a separation position separated from the fixing member and the mounting position, and By having a displacement means for displacing the sensor between the separation position and the mounting position, even if the jammed transfer paper breaks and becomes a corner, it may accidentally come out of the opening or not in contact with the sensor protection member. Even when the non-contact temperature sensor is intruded from between the temperature sensor, the non-contact temperature sensor can be reliably prevented from being stained or damaged by the jammed transfer paper.

According to the fifth aspect of the present invention, the non-contact temperature sensor is configured so as to be displaceable with respect to its own mounting position between a separation position separated from the fixing member and the mounting position, so that the non-contact temperature sensor can be displaced. By having the displacement means for displacing the sensor between the separation position and the attachment position, it is possible to prevent the non-contact temperature sensor from being damaged due to the force applied by the jammed transfer paper.

According to the sixth aspect of the present invention, since the non-contact temperature sensor is composed of a thermistor assembled in a bridge circuit, in addition to the effects of the above-mentioned inventions, the sensitivity is good, the response is fast, and An inexpensive non-contact temperature sensor can be obtained.

According to the seventh aspect of the present invention, the non-contact temperature sensor is connected to the temperature control device including the amplifier for controlling the temperature of the heat fixing fixing member via the connector. The fixing member and the non-contact temperature sensor are configured in a replaceable fixing device unit, and the amplifying unit and the temperature control device are disposed outside the fixing device unit. By exchanging the non-contact temperature sensor at the time of replacement, a new non-contact temperature sensor free from dirt or the like can be obtained.

According to the eighth aspect of the present invention, the non-contact temperature sensor is connected to the temperature control device including the amplifier for controlling the temperature of the fixing member for thermal fixing via the connector. The fixing member and the non-contact temperature sensor are configured in a replaceable fixing device unit, and the amplification unit and the temperature controller are arranged outside the fixing device unit. Is replaced with a new non-contact temperature sensor free of dirt and the like.

According to the ninth aspect of the present invention, in addition to the effect of the eighth aspect, the non-contact temperature sensor is formed of a thermistor assembled in a bridge circuit.
An inexpensive non-contact temperature sensor having good sensitivity, quick response, and low cost can be obtained.

According to the tenth aspect of the present invention, in a fixing device in which the heat fixing fixing member is a heat fixing heat roller, the effects of any one of the first to ninth aspects can be obtained. it can.

According to the eleventh aspect of the present invention, in a fixing device in which the heat fixing fixing member is a heat fixing heat belt, the effect of the invention according to any one of the first to ninth aspects can be obtained. it can.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a main section of a fixing unit of a fixing device according to a first embodiment and a control configuration of a temperature control device.

FIG. 2 is a front sectional view of a main part of FIG. 2;

FIG. 3 is a schematic circuit diagram showing an example in which a non-contact temperature sensor is assembled in a bridge circuit.

FIG. 4 is a front cross-sectional view illustrating a main configuration of a fixing device according to a second exemplary embodiment.

FIG. 5 is a configuration diagram illustrating a main section of a fixing unit of a fixing device according to a fifth embodiment and a control configuration of a temperature control device.

FIG. 6 is a front sectional view showing a configuration of a main part of a fixing device according to a sixth embodiment.

FIG. 7 is a configuration diagram illustrating a plan cross section of a main part of a fixing device and a control configuration of a temperature control device according to a third embodiment.

FIG. 8 is a configuration diagram illustrating a plan cross-section of a main part of a fixing device and a control configuration of a temperature control device according to a seventh embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixing heat roller as a fixing member for thermal fixing 2 Heater 3 Non-contact temperature sensor 4 Sensor protection member 5 Opening 6,36 Fixing unit as a fixing device unit 8a Socket forming a connector 8b Jack forming a connector 10 Temperature Amplifying unit constituting the control unit 12 Temperature controlling unit constituting the temperature control unit 14 Temperature control unit 15 Infrared ray 16 Pressure roller 17 Movable member constituting the displacement means 19 Torsional coil spring constituting the displacement means 21 Fixing roller 22 Heating Roller 23 Fixing heat belt as a fixing member for heat fixing 24 Pressure roller 25 Compression coil springs constituting displacement means TH1 to TH4 Thermistor P Transfer paper

Claims (11)

[Claims] 1. A fixing device comprising: a fixing member for heat fixing; and a non-contact temperature sensor disposed in the vicinity of the fixing member and detecting a peripheral surface temperature of the fixing member in a non-contact state. A fixing device comprising a sensor protection member between the fixing device and the non-contact temperature sensor. 2. The fixing device according to claim 1, wherein said sensor protection member has an opening for receiving infrared rays from said fixing member. 3. The fixing device according to claim 2, wherein the size of the opening is equal to or larger than the size of a substantial infrared receiving surface of the non-contact temperature sensor. 4. The fixing device according to claim 1, wherein the non-contact temperature sensor is located at a position where the non-contact temperature sensor is mounted.
Displacement means for displacing the non-contact temperature sensor between the detached position and the attachment position is provided so as to be displaceable between a detached position separated from the fixing member and the attachment position. Fixing device. 5. A fixing device comprising: a fixing member for thermal fixing; and a non-contact temperature sensor disposed near the fixing member and detecting a peripheral surface temperature of the fixing member in a non-contact state. Is relative to its own mounting position
Displacement means for displacing the non-contact temperature sensor between the detached position and the attachment position is provided so as to be displaceable between a detached position separated from the fixing member and the attachment position. Fixing device. 6. A fixing device according to claim 1, wherein said non-contact temperature sensor comprises a thermistor assembled in a bridge circuit. 7. A temperature control device according to claim 1, wherein said non-contact temperature sensor includes an amplifier for controlling the temperature of said fixing member via a connector. Wherein the fixing member and the non-contact temperature sensor are configured in a replaceable fixing device unit, and the amplification unit and the temperature control device are disposed outside the fixing device unit. Fixing device. 8. A fixing device comprising: a fixing member for heat fixing; and a non-contact temperature sensor disposed near the fixing member and detecting a peripheral surface temperature of the fixing member in a non-contact state. Is connected to a temperature control device including an amplifier for controlling the temperature of the fixing member via a connector, and the fixing member and the non-contact temperature sensor are configured in a replaceable fixing device unit. A fixing device, wherein the amplifying unit and the temperature control device are disposed outside the fixing device unit. 9. The fixing device according to claim 8, wherein said non-contact temperature sensor comprises a thermistor assembled in a bridge circuit. 10. The fixing device according to claim 1, wherein the fixing member is a heat roller for heat fixing. 11. The fixing device according to claim 1, wherein the fixing member is a heat belt for heat fixing.