JP2000214721A - Fixing device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make works of a jam processing and maintenance or the like performed in a short waiting time and safely by providing an attention arousing means capable of detecting and displaying that a fixing device is in a prescribed high temp. state in an image forming device. SOLUTION: The attention arousing means detecting and displaying that the fixing device is in a prescribed high temp. state is provided in this fixing device. For example, a semiconductor-type thermoelectric element 2 in which the Peltier effect is used is used in the case of detecting the temp. of a dielectric heat-type fixing roller 1. This element 2 is constituted by having a P type semiconductor 23 and an N type semiconductor 24 between the high temp.-side electrodes 21 being on the side near the fixing roller 1 and the low temp.-side electrode 22 being on the opposite side. The low temp.-side electrode 22 is made to be in room temp. state in the ambience. Then, in this device, when the roller 1 is in a prescribed high temp. state, the element 2 generates a thermoelectric effect by the temp. difference between the temp. of the roller 1 and the temp. of the ambience to drive an LED 3 and then the LED 3 displays that the fixing roller 1 is in the prescribed high temp. state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus such as a printer, a facsimile, a copying machine, and the like, and a heat fixing device mounted on the apparatus.

[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 such as paper or an OHP sheet, the recording material is sandwiched between a heating 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. As a method of heating the roller, a radiant heating method of heating with a halogen lamp built in a roller made of metal such as Al or SUS, a heat-resistant insulating layer is arranged on the inner peripheral surface of a cylindrical body made of a metal pipe, A heating resistor such as a ceramic heater is provided on the inner surface, or a surface heating method in which the roller itself is formed by a heating resistor, or a vortex caused by a high-frequency magnetic field generated in an induction coil containing a roller made of a metal conductor inside. There is an induction heating method of heating by electric current.

[0003]

If a jam occurs near the fixing device in which the above-described heating source is arranged in the roller, the user or the repairer can remove the jammed paper in a range where the temperature of the member becomes high. Must. If the power supply to the heating source is off and it is in a relatively low temperature state that is falling to room temperature, there is no problem even if the rollers and surrounding members are touched, but during on-off control or immediately after power off, Touching a high temperature member in a relatively high temperature state may cause burns. It is not easy to determine how high the temperature is in the related art, and it is merely determined by carefully touching a member that has become hot. Waiting for sufficient cooling hinders work efficiency. There is a similar problem during maintenance. Any device that uses a halogen lamp as a heating source and has a configuration that allows the lamp light to be recognized from the outside is sufficient to determine whether or not power is being supplied. It is not easy to easily determine whether work such as maintenance and maintenance can be performed safely.

In view of the above-described problems, the present invention is to provide a fixing device having a heating source inside a roller and an image forming apparatus having the fixing device to perform operations such as jam processing and maintenance with a short standby time and safely. The task is to be able to

[0005]

An object of the present invention is to provide a fixing device for nipping and conveying a recording material to fix a toner image on the recording material, wherein the fixing device includes a heating source in at least a heating roller. The problem is solved by providing an alerting means for detecting and displaying that the is in a predetermined high temperature state. The predetermined high temperature state means a temperature state where a burn is caused when touched.

It is preferable that the warning means includes a thermoelectric element based on the Peltier effect and a display driven by the thermoelectric element. Further, the alerting means may include a heat-responsive element, a circuit for detecting a state of the element, and a display driven by the detection circuit. At this time, the heat responsive element is, for example, any of a thermistor, a thermocouple, or a heat sensor. It is also preferable that a drive source for driving the above-mentioned alerting means is provided in the heating roller.

[0007] An image forming apparatus having a fixing device having the above-described configuration and configured to be able to display a message by the above-mentioned alerting means on its operation panel also solves the above-mentioned problem. Instead of providing the entire warning device in the fixing device, a device for detecting that the fixing device is in a predetermined high temperature state is provided in the fixing device, and a display unit for displaying the detection result is provided in the image forming device. It may be.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described based on an example shown in the drawings. In the following examples, attention is paid to the vicinity of the fixing roller (heating roller) mounted on the image forming apparatus, and unless otherwise noted, the parts that are not described are the same as those of the conventional apparatus (fixing apparatus and image forming apparatus). Is to be understood as

In FIG. 1 conceptually showing the first embodiment, for example, a semiconductor type thermoelectric element 2 utilizing the Peltier effect is used for temperature detection of an induction heating type fixing roller 1. The thermoelectric element 2 has a P-type semiconductor 23 and an N-type semiconductor 24 between a high-temperature side electrode 21 on the side close to the fixing roller 1 and a low-temperature side electrode 22 on the opposite side. The low-temperature side electrode 22 is in a room temperature state in an atmosphere. The thermoelectric element 2 is fixedly disposed at a distance of about several mm from the surface of the fixing roller 1. However, the thermoelectric element 2 is separated from the fixing roller using an unillustrated contact / separation mechanism, for example, during operation of the apparatus, and comes into contact after the operation is completed. In this way, the fixing roller may come into contact with or separate from the surface of the fixing roller as needed.

The light emitting diode (LED) 3 is driven by the PN electrode of the thermoelectric element 2. In this case, when the temperature of the low-temperature side electrode 22 rises due to conduction heat as time elapses, the temperature of the low-temperature side electrode 22 increases. LED with reduced temperature difference
In order to avoid this, the radiator plate 4 is attached to the low-temperature-side electrode 22 to keep the same as the ambient temperature. Although not shown, when the thermoelectric effect is small and a voltage enough to drive the LED 3 cannot be obtained, a drive circuit using an electronic circuit may be inserted between the thermoelectric element 2 and the LED 3. With the above configuration, when the fixing roller 1 is in a predetermined high temperature state, the thermoelectric element 2 generates a thermoelectric effect due to a temperature difference from the atmosphere, and the LED 3 is driven so that the fixing roller 1 is in a predetermined high temperature state. To show that

In FIG. 2 conceptually showing the second embodiment, the configuration of the thermoelectric element 2 and the arrangement of the thermoelectric element 2 with the fixing roller 1 are the same as those in FIG. Just LED3
Is not the fixing roller side but the room temperature side, that is, the low temperature side electrode 2
2 are connected. Even with such a configuration, the LED 3 can be driven in the same manner according to the same principle as in the above example.

As is well known, thermoelectric elements have reversibility, so the above configuration can be realized using a commercially available thermoelectric cooling element. In the above two examples, since the high temperature display mechanism is all disposed near the fixing roller, high temperature display can be performed even when the fixing device is removed from the image forming apparatus.

FIG. 3 conceptually shows a third embodiment.
A thermistor 5 is used for detecting the temperature of the fixing roller 1. A thermocouple may be used instead of the thermistor 5.
Then, the state of the thermistor 5 is detected by the detection circuit 6, and L
The display 7 such as an ED is driven. The detection circuit 6 can be easily constituted by an operational amplifier and a transistor circuit. A detection circuit of any configuration may be used as long as it can detect the state of the thermistor and can drive the display. A typical circuit example using an operational amplifier is shown in FIG. In this case, the electronic circuit may be mounted on the main unit side, but by using a battery as a power source and mounting all circuits on the fixing roller side, the temperature state of the fixing roller can be detected even when the fixing roller is removed from the main unit. It is good also as a structure which can be performed.

As in the above three examples, if a mechanism capable of displaying the high temperature state only by the fixing roller portion without receiving power supply from the main body side is used, the display can be turned on even when the main body power is turned off. It can be alert and safe.

FIG. 5 conceptually shows a fourth embodiment.
An infrared sensor 8 is used to detect the temperature of the fixing roller 1. The output of this sensor 8 is detected by the electronic circuit 9 and LE
The display 7 such as D is driven. Although the electronic circuit is not shown in detail, it may be constituted by an ordinary electronic circuit for an infrared sensor. According to the configuration of the present example, the temperature of the fixing roller can be detected at a position somewhat distant.

In all of the above four examples, the display device in the high temperature state is arranged near the fixing roller 1 and therefore near the detecting device. As shown conceptually in FIG. By displaying a message that calls attention such as "Caution for high temperature" on the operation panel 11 via the CPU 10 of the image forming apparatus main body, it is possible to call attention even before opening the machine cover. Instead of disposing a display near the fixing roller, it is of course possible to display a message only on the operation panel 11.

[0017]

According to the present invention, a fixing device for nipping and conveying a recording material to fix a toner image on the recording material is provided. Since it is provided with an alerting means for detecting and displaying the high temperature state of the device, it is possible to safely carry out operations such as jam clearance and maintenance with a short standby time. If the heating source is a halogen lamp and the lamp light can be recognized from the outside, it is possible to double-check with the judgment based on whether or not the lamp light is on. In addition, even those that use other heating sources not only rely on the skin feeling, but also safely treat jams, etc.
Moreover, it can be performed promptly.

If the warning means comprises a thermoelectric element based on the Peltier effect and a display driven by the thermoelectric element, the effect of the present invention can be obtained with a simple configuration, and the fixing roller can be mounted on the main body. It is possible to perform detection even in a state where the device is removed from the device.

If the warning means comprises a heat-responsive element, a circuit for detecting the state of the element, and a display driven by the detection circuit, the effects of the present invention can be reliably obtained. When the thermal response element is an infrared sensor, the temperature of the fixing device can be detected separately from the fixing device, and the degree of freedom in design can be secured.

If a driving source for driving the above-mentioned warning means is provided in the fixing roller, it is possible to detect even if the warning means having the thermal response element is removed from the main body. is there. Further, even when the power of the image forming apparatus itself is turned off, detection is not prevented.

If the fixing device having the above-mentioned configuration is provided and a message by the alerting means can be displayed on the operation panel of the image forming apparatus, it is possible to call attention before opening the cover of the machine. Instead of providing the entire warning device in the fixing device, a device for detecting that the fixing device is in a predetermined high temperature state is provided in the fixing device, and a display unit for displaying the detection result is provided in the image forming device. Even if it is, it is possible to call attention before opening the cover.

[Brief description of the drawings]

FIG. 1 is a conceptual configuration diagram of a fixing roller portion according to a first embodiment of the present invention.

FIG. 2 is a conceptual configuration diagram of a fixing roller portion according to a second embodiment.

FIG. 3 is a conceptual configuration diagram of a fixing roller portion according to a third embodiment.

FIG. 4 is a configuration diagram illustrating an example of a detection circuit.

FIG. 5 is a conceptual configuration diagram of a fixing roller portion according to a fourth embodiment.

FIG. 6 is a conceptual diagram illustrating an example of a case where display is performed on an operation panel of the image forming apparatus main body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixing roller 2 Thermoelectric element 3 LED 4 Heat sink 21 High-temperature side electrode 22 Low-temperature side electrode 23 P-type semiconductor 24 N-type semiconductor

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 35/06 H01L 35/06 35/28 35/28 C (72) Inventor Jiro Ouchi Shibata-gun, Miyagi Shibata-cho, Nakamichi, Shinmei-do 3-1 Tohoku Ricoh Co., Ltd. F-term (reference) 2H027 DA12 ED25 EJ17 GA42 GA47 GB02 GB08 HA02 2H033 AA33 AA37 AA42 BA31 BA39 BB01 CA02 CA58

Claims (7)

[Claims] 1. A fixing device for nipping and conveying a recording material to fix a toner image on the recording material, wherein the fixing device is provided with a heating source at least in a heating roller, wherein the fixing device is in a predetermined high temperature state. A warning device for detecting and displaying an image. 2. The fixing device according to claim 1, wherein the alerting means includes a thermoelectric element based on the Peltier effect and a display driven by the thermoelectric element. 3. The fixing device according to claim 1, wherein the warning unit includes a heat responsive element, a circuit for detecting a state of the element, and a display driven by the detection circuit. 4. The fixing device according to claim 3, wherein the heat responsive element is one of a thermistor, a thermocouple, and a heat sensor. 5. The heating roller according to claim 3, wherein a driving source for driving the warning unit is provided on the heating roller.
3. The fixing device according to claim 1. 6. An image forming apparatus comprising the fixing device according to claim 1, wherein a message by the warning means can be displayed on an operation panel thereof. 7. An image forming apparatus having at least a fixing device provided with a heating source in a heating roller, wherein the fixing device includes means for detecting that the fixing device is in a predetermined high temperature state, and the detection result is displayed. An image forming apparatus comprising a display unit provided in the image forming apparatus.