JP3820046B2 - Fixing apparatus and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a printer, a facsimile machine, a copying machine, and the like, and a heat fixing apparatus mounted on the apparatus.
[0002]
[Prior art]
In an image forming apparatus using toner for forming a visible image, a toner image is sandwiched and conveyed between a heating roller and a pressure roller in order to fix the toner image on a recording material such as paper or an OHP sheet. In general, a heat and pressure type fixing device for fixing the image on the recording material is used. As a method of heating the roller, a radiant heating method of heating by a halogen lamp incorporated 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, Vortex caused by a high-frequency magnetic field generated in a surface heating method in which a heating resistor such as a ceramic heater is provided on the inner surface side, or the roller itself is formed of a heating resistor, or in an induction coil containing a roller made of a metal conductor. There are induction heating methods that heat by current.
[0003]
[Problems to be solved by the invention]
When a jam occurs in the vicinity of the fixing device in which the heating source as described above is arranged in the roller, the user or a repairman must remove the jammed paper in a range where the member becomes hot. Optionally feeding to the heating source is turned off, if a relatively low temperature state during lowering to room temperature, but not to touch the roller and the peripheral members thereof problem, etc. after being off control and power supply OFF in a relatively high temperature conditions, it becomes possible burns on contact with the hot member. It is not easy to determine the high temperature state in the prior art, and it is only determined by carefully touching a member that has become hot. If you wait for it to cool down sufficiently, work efficiency will be hindered. There is a similar problem during maintenance. If it is a device that uses a halogen lamp as a heat source and is configured to recognize the lamp light from the outside, it is possible to judge whether or not power is being supplied, but jam processing It is not easy to easily determine whether work such as maintenance can be performed safely.
[0004]
Therefore, in view of the above-described problems, the present invention uses a very simple configuration in a fixing device having a heating source in a roller or an image forming apparatus having the fixing device, and performs operations such as jam processing and maintenance for a standby time. It is an object of the present invention to be able to carry out the process quickly and safely, and in particular, to be able to continuously detect the electrical temperature of the fixing device even when the fixing device is removed from the main body of the image forming apparatus .
[0005]
[Means for Solving the Problems]
The above problem is that the fixing device is a fixing device in which the recording material is nipped and conveyed to fix the toner image on the recording material, and the fixing device has a heating source at least in the heating roller. This is solved by providing a warning means for detecting and displaying, and the warning means includes a thermoelectric element based on the Seebeck effect and a display driven by electric power generated by the thermoelectric element . The predetermined high temperature state means a temperature state that causes burns when touched.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The details of the present invention will be described based on examples 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 specified, the parts not described are the same as those of conventional apparatuses (fixing apparatus and image forming apparatus). Should be understood.
[0009]
In FIG. 1 conceptually showing the first embodiment, for example, a semiconductor type thermoelectric element 2 utilizing the Seebeck effect is used for temperature detection of an induction heating type fixing roller 1. The thermoelectric element 2 includes 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 the atmosphere. The thermoelectric element 2 is disposed so as to be separated from the surface of the fixing roller 1 by several mm. However, the thermoelectric element 2 is separated from the fixing roller when the apparatus is operated by using a contact / separation mechanism (not shown), and contacts after the operation is completed. As described above, it may come into contact with or separate from the surface of the fixing roller as necessary.
[0010]
The light emitting diode (LED) 3 is driven by the PN electrode of the thermoelectric element 2, but in this case, when the temperature of the low temperature side electrode 22 rises due to conduction heat as time passes, the temperature difference from the high temperature side is increased. Since the driving time of the LED 3 is reduced and the heat radiation plate 4 is attached to the low temperature side electrode 22 in order to avoid this, the temperature is kept at the same level as the ambient temperature. Although not shown, when the thermoelectric effect is small and a voltage sufficient to drive the LED 3 cannot be obtained, a driving circuit by 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 to cause the fixing roller 1 to be in a predetermined high temperature state. Is displayed.
[0011]
In FIG. 2 conceptually showing the second embodiment, the configuration of the thermoelectric element 2 and the arrangement relationship of the thermoelectric element 2 with the fixing roller 1 are the same as in the example of FIG. However, the LED 3 is connected not to the fixing roller side but to the room temperature side, that is, the low temperature side electrode 22. Even in such a configuration, the LED 3 can be driven in the same manner based on the same principle as in the above example.
[0012]
As is well known, since thermoelectric elements are reversible, the above configuration can also be realized using commercially available thermoelectric cooling elements. In the above two examples, since all the high temperature display mechanisms are arranged in the vicinity of the fixing roller, high temperature display can be performed even when the fixing device is removed from the image forming apparatus.
[0014]
As in the above two examples , if the mechanism can display the high temperature state only with the fixing roller part without receiving power supply from the main body side, the display can be lit even when the main body power is turned off. Is safe.
[0016]
In the above two examples, the high temperature display is arranged on the fixing roller 1 and therefore in the vicinity of the detecting device . However, as conceptually shown in FIG. By displaying a warning message such as “Caution on high temperature” on the operation panel 11 via the CPU 10 of the image forming apparatus main body, it is possible to call attention before opening the machine cover. Of course, it is also possible to display a message only on the operation panel 11 instead of arranging a display in the vicinity of the fixing roller.
[0017]
【The invention's effect】
According to the present invention, in a fixing device that sandwiches and conveys a recording material and fixes a toner image on the recording material, the fixing device includes a heating source in at least a heating roller, and the fixing device is in a predetermined high temperature state. Since a warning means for detecting and displaying this is provided, operations such as jam handling and maintenance can be performed safely with a short standby time. If the heating source is a halogen lamp and the lamp light can be recognized from the outside, a double check with the judgment based on whether or not the lamp light is lit is possible. Further, even those using other heating sources can not only rely on the feeling of skin but also can safely perform jam processing and the like quickly.
[0019]
Since the alerting means includes a thermoelectric element based on the Seebeck effect and a display driven by electric power generated by the thermoelectric element, the effect of the present invention can be obtained with a simple configuration, and the fixing roller It is possible to detect even when the is removed from the main body.
[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 diagram illustrating an example when display is performed on an operation panel of the image forming apparatus main body.
[Explanation of symbols]
1 Fixing roller 2 Thermoelectric element 3 LED
4 Heat Dissipation Plate 21 High Temperature Side Electrode 22 Low Temperature Side Electrode 23 P-type Semiconductor 24 N-type Semiconductor

Claims (2)

In a fixing device that sandwiches and conveys a recording material to fix a toner image on the recording material, and includes a heating source at least in a heating roller,
A warning means for detecting and displaying that the fixing device is in a predetermined high temperature state is provided, and the warning means includes a thermoelectric element based on the Seebeck effect and a display driven by electric power generated by the thermoelectric element. A fixing device characterized by the above.   An image forming apparatus comprising the fixing device according to claim 1.

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