JP5187015B2 - Heat dissipation device and image forming apparatus using the same - Google Patents

Description

The present invention relates to an electronic substrate device including a heat radiating device that is disposed in a ventilated atmosphere to cool a semiconductor element , and an image forming apparatus using the electronic substrate device .

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a copier having an electrophotographic process, a printer, a facsimile machine, a multifunction machine, or a multi-function machine called MFP (Multi Function Peripherals), an electrostatic latent image formed on a photosensitive drum is used. The image is developed to form a toner image, the toner image is primarily transferred to an intermediate transfer belt, and then further transferred to a recording sheet, and then fixed by a fixing device to form an image. In the fixing device, a recording sheet on which a toner image is secondarily transferred is passed between a fixing roller having a built-in heater and a pressure roller facing the fixing roller, whereby the toner image is heated and fixed.

  In such a fixing device, a large-capacity semiconductor element such as a triac (bidirectional thyristor) that controls the heater on / off is used as a substrate for the temperature control device that controls the temperature of the heater. Such a triac is usually fitted with a heat sink, but as a further temperature countermeasure, increase the surface area of the heat sink, increase the current rating of the triac, or increase the air volume of the cooling fan. Is generally done.

  However, increasing the surface area of the heat sink or increasing the current rating of the triac will increase the size of the device. Further, when the air volume of the fan is increased, a noise problem occurs.

  The image forming apparatus operates with a commercial AC power supply. However, when the input voltage to the heater decreases due to a decrease in power supply voltage or the like, the current flowing through the heater decreases. In response to this, in order to keep the fixing roller at a predetermined temperature, control is performed such that the on-time of the triac that controls the temperature of the heater becomes longer. As a result, the amount of heat generated by the triac becomes larger than that during normal operation, and it is necessary to take measures against further temperature measures.

In addition, as one of the temperature countermeasures, a blow grill, a wind direction switching plate, a plate stopper for fixing the wind direction switch plate, a shape memory alloy spring connecting the blow grill and the wind direction switching plate, and a lower cylinder are provided. An apparatus has been proposed in which a shape memory alloy spring responds to the air-conditioning air temperature, thereby setting an optimum blowing angle (Patent Document 1).
JP-A-8-121854

  However, in the apparatus of Patent Document 1 described above, it is necessary to use dedicated parts such as a wind direction switching plate, a plate stopper, and a shape memory alloy spring having a special shape, and the number of parts cannot be reduced. There's a problem.

  The triac that controls the temperature of the heater described above increases the amount of heat generation due to a decrease in the power supply voltage, but the transformers constituting the low-voltage power supply circuit tend to decrease the amount of heat generation due to a decrease in the power supply voltage. There is.

  In the device of Patent Document 1, it is effective when the temperature inside the device rises. For example, when the triac and the transformer as described above are provided in the area of one substrate, respectively. However, even if the temperature of a part of the region increases, the temperature of the other part of the region may decrease, and in this case, the necessary region cannot be efficiently cooled.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an electronic substrate device including a heat dissipation device that has a small number of components and can be easily miniaturized, and an image forming apparatus using the electronic substrate device .

Electronic board device according to the present invention is an electronic board device that will be placed in the atmosphere of Ventilation, semiconductor elements and heat dissipation device for turning on and off the supply of power is mounted on the first circuit region on the substrate, A power circuit including a power transformer is mounted in a second circuit area adjacent to the first circuit area on the substrate, and heat generation in the second circuit area occurs when the amount of heat generated in the first circuit area increases. The heat dissipation device is formed in a plate shape with a temperature-sensitive deformable material whose shape changes with a temperature change, and on one surface thereof, a mounting region for mounting the semiconductor element , and the mounting A region that is continuous with the region and is provided with a ventilation region for receiving ventilation, and when the temperature rises to a predetermined temperature, the surface of the ventilation region and the attachment region The angle between the surface increases, thereby has the ventilation region is configured to increase the airflow to more received by the semiconductor element ventilation, when the heat dissipation device rises to a predetermined temperature, By increasing the angle formed between the surface of the ventilation region and the surface of the attachment region, the ventilation to the semiconductor element is increased and the ventilation to the second circuit region is reduced, and the heat dissipation device is more than a predetermined temperature. The air flow to the semiconductor element is reduced and the air flow to the second circuit region is increased by decreasing the angle formed between the surface of the air flow region and the surface of the mounting region when the air flow decreases. Yes.

For example, when the like drop in the power supply voltage the temperature of the semiconductor device rises, the heat dissipation device is deformed to increase the air amount to the semiconductor element, to further cool the semiconductor element.

According to the present invention, it is possible to provide an electronic substrate device including a heat dissipation device that has a small number of components and can be easily miniaturized, and an image forming apparatus using the electronic substrate device .

[Image forming apparatus]
FIG. 1 is a diagram illustrating an overall configuration of an image forming apparatus GK according to an embodiment of the present invention, FIG. 2 is a diagram illustrating a schematic configuration of a fixing device F, and FIG. 3 is a part of a control circuit SK of the image forming apparatus GK. FIG.

  In FIG. 1, an image forming apparatus GK is an image forming apparatus having many functions such as copy, scanner, facsimile, network printing, document server, and file transfer, and is a multifunction peripheral or MFP (Multi Function Peripherals). Sometimes called. Therefore, for example, the image forming apparatus GK also has a printer function for performing printing in accordance with image information supplied from a computer or the like.

  The image forming apparatus GK includes an image forming section B disposed at the center, a cassette portion CS provided below the recording medium accommodating cassettes C1 to C4, an image reading apparatus S provided above, and the like. Is done. The image reading apparatus S is equipped with an automatic document feeder ADF and an operation panel PA.

  The automatic document feeder ADF can be opened and closed on the upper surface of the main body, and also serves as a cover that covers a document placed on the glass plate g1 of the image reading device S. The operation panel PA is equipped with a key group Ke such as a start key for instructing image formation or facsimile transmission in copying, a numeric keypad for setting the number of image formations, a liquid crystal display unit 18, a speaker 19, and the like. The liquid crystal display unit 18 displays various messages and data such as a display reflecting the key operation by the user, an instruction menu for the user, and information from the image forming unit B.

  The image reading device S can optically read an image of a stationary document set on the platen glass plate g1, and also from the document loading tray a1 toward the document discharge tray a2 by the automatic document feeder ADF. The image of the conveyed document can also be optically read when moving along the document panning glass plate g2 in the middle of the document.

  The image data (image data) read by the image reading device S is sent to the image forming unit B, where an actual image is formed or transmitted by facsimile.

  The image forming unit B is a tandem type color image forming unit that forms a toner image on a recording medium such as recording paper P by an electrophotographic method. That is, in the image forming unit B, the yellow image forming unit UY, the magenta image forming unit UM, the cyan image forming unit UC, and the black image forming unit UK are arranged along the intermediate transfer belt b. The toner images of the respective colors formed by the above are primarily transferred and superimposed on the intermediate transfer belt b. The multiple toner images superimposed on the intermediate transfer belt b are secondarily transferred to the recording paper P supplied from the recording medium storage cassettes C1 to C4, and are fixed by the fixing device F to form a color image.

  Note that the image forming unit B can also form a monochrome image, and can also perform image formation using any two or three color image forming units. Further, the image forming unit B may be a color image forming unit of another type, or may be an image forming unit dedicated to monochrome. Further, when image data is transmitted from a computer or the like (not shown), the image data can be formed into an actual image by the image forming unit B or transmitted by facsimile.

  In FIG. 2, the fixing device F includes a fixing roller f1, a pressure roller f2, a thermistor 2, a halogen lamp (halogen lamp heater) 3, and the like.

  The fixing roller f1 is rotatably supported by a support member (not shown) and is rotated by a driving force from a driving source (not shown). The fixing roller f1 includes a halogen lamp 3 as a fixing heater. When the halogen lamp 3 is turned on, the fixing roller f1 is heated to a temperature necessary for fixing the toner image. The temperature of the fixing roller f1 is detected by the thermistor 2, and the temperature is controlled by the control unit 4 so that the temperature of the fixing roller f1 becomes a predetermined temperature.

  The pressure roller f2 is pressed against the fixing roller f1 during fixing and contacts the fixing roller f1 in a pressurized state. As a result, a nip NB is formed between the fixing roller f1 and the pressure roller f2. When the recording paper P onto which the toner image has been secondarily transferred passes through the nip portion NB, the toner image is heated and pressurized on the recording paper P and fixed thereby. Thereafter, the recording paper P is discharged onto the paper discharge tray T by the discharge roller R.

  Next, FIG. 3 shows a circuit portion particularly related to the lighting of the halogen lamp 3 and a transformer circuit portion that outputs a secondary voltage. Also shown is a control unit 4 that controls the entire image forming apparatus GK.

  That is, in FIG. 3, the control circuit SK includes the control unit 4, the heater circuit HK, the power supply circuit DK, and the like. The control circuit SK is supplied with AC 100V AC power from the commercial AC power supply 1 via the fuse 21.

  The control unit 4 is provided with a temperature control unit 27 for adjusting the temperature of the halogen lamp 3. The temperature control unit 27 controls the triac 5 based on the temperature signal S 1 detected by the thermistor 2. Then, the electric power supplied to the halogen lamp 3 is controlled to adjust the amount of heat generated, and the temperature of the fixing roller f1 is adjusted.

  The heater circuit HK includes the thermistor 2, the halogen lamp 3, the triac 5, the photocoupler 17, and the resistor 2r.

  The AC power supplied from the AC power supply 1 via the fuse 21 is supplied to the halogen lamp 3 via the triac 5 that is on / off controlled. The magnitude of the AC power supplied to the halogen lamp 3 depends on the on time of the triac 5. As the ON time of the triac 5 increases, the time during which current flows through the halogen lamp 3 increases, and the amount of heat generated by the halogen lamp 3 increases. Further, as the on-time of the triac 5 increases, the current flowing through the triac 5 increases, so the amount of heat generated by the triac 5 also increases.

  The on / off control of the triac 5 is performed by applying a control signal S2 from the temperature control unit 27 to its gate terminal via the photocoupler 17. The temperature of the fixing roller f1 is detected by the thermistor 2, and a voltage corresponding to the temperature is generated at both ends of the resistor 2r. The voltage across the resistor 2r is input to the temperature control unit 27 as the temperature signal S1.

  The temperature control unit 27 outputs a control signal S2 based on the input temperature signal S1 and the temperature adjustment data stored therein. A known control method can be used for such control in the temperature control unit 27 itself.

  By the way, in this embodiment, when the temperature control part 27 is performing normal control, suppose that the voltage of AC power supply 1 was fluctuate | varied. For example, when the voltage of the AC power supply 1 decreases, if the control in the temperature control unit 27 remains as it is and the control signal S2 does not change, the current flowing through the halogen lamp 3 and the triac 5 decreases. 3 is reduced, and therefore the temperature of the fixing roller f1 is lowered. Therefore, in that case, the temperature control unit 27 actually changes the control signal S2 so that the on-time of the triac 5 is increased, thereby performing control so that the current flowing through the halogen lamp 3 does not decrease.

  Then, since the on-time of the triac 5 increases, the amount of heat generated by the triac 5 increases this time. Therefore, it is necessary to further cool the triac 5. The triac 5 is provided with a heat dissipation device HS as described later.

  The power supply circuit DK includes an inrush current preventing resistor 22, a primary rectifier circuit 6, a starting circuit 7, a primary smoothing capacitor 8, a control IC 10, an FET (field effect transistor) 11, a diode 13, a secondary smoothing capacitor 14, and a diode. 23, a capacitor 24, a transformer 33, and the like.

  The AC power supplied from the AC power source 1 is input to the primary rectifier circuit 6 and the starting circuit 7 through the current fuse 21 and the resistor 22. The AC power is full-wave rectified by the primary rectifier circuit 6, smoothed by the primary smoothing capacitor 8, and becomes DC power. The DC power is turned on and off (chopped) at high speed by the FET 11 and supplied to the main winding 9 of the transformer 33.

  The activation circuit 7 activates the control IC 10, and the control IC 10 performs on / off control of the FET 11 at high speed. The on / off frequency of the FET 11 is, for example, about several hundred Hz to several hundred KHz. As a result, an alternating current flows through the main winding 9 of the transformer 33, and alternating-current power corresponding to the turn ratio is extracted from the secondary winding 15 and the auxiliary winding 12.

  The AC power from the secondary winding 15 is rectified and smoothed by the diode 13 and the secondary smoothing capacitor 14, and is output as a DC voltage of 24V, for example. The DC voltage of 24V is supplied to the control circuit or drive circuit of the image forming apparatus GK.

  The AC power from the auxiliary winding 12 is rectified and smoothed by the diode 23 and the capacitor 24 and supplied to the control IC 10 and the FET 11.

  By the way, in the present embodiment, when the voltage of the AC power supply 1 decreases as described above, the current flowing through the transformer 33 decreases, so that the amount of heat generated by the transformer 33 is small, contrary to the case of the triac 5. The temperature drops.

In the present embodiment, the heat dissipation device HS performs efficient cooling on the triac 5 by utilizing the fact that the change in the amount of heat generated due to the voltage fluctuation of the AC power supply 1 is reversed between the triac 5 and the transformer 33. It is a thing.
[Heat dissipation device]
That is, the heat dissipating device HS is disposed in a ventilated atmosphere and cools the triac 5 that is an electronic component. The heat dissipating device HS is formed in a plate shape by a temperature-sensitive deformable material whose shape changes with temperature change, and on one surface thereof, an attachment region for attaching an electronic component, a region continuous to the attachment region, and ventilation. Ventilation area for receiving. When the heat dissipation device HS rises to a predetermined temperature, the angle formed between the surface of the ventilation region and the surface of the mounting region increases, and thereby the ventilation region receives more ventilation and increases ventilation to the electronic component. Configured as follows.

  In addition, part or all of the control circuit SK is mounted as an electronic board device including the heat dissipation device HS.

  That is, in an electronic board device arranged in a ventilated atmosphere, an electronic component and a heat dissipation device are mounted in a first circuit area of the board, and a second circuit is provided in an area adjacent to the first circuit area of the board. When the amount of heat generated in the first circuit region increases, the amount of heat generated in the second circuit region decreases, and the heat dissipation device is shaped like a plate by a temperature-sensitive deformable material whose shape changes with temperature changes. One of the surfaces is provided with an attachment area for attaching the electronic component, and a ventilation area that is continuous with the attachment area and receives ventilation, and when the temperature rises to a predetermined temperature The angle formed between the surface of the ventilation area and the surface of the mounting area is increased, whereby the ventilation area is configured to receive more ventilation and increase ventilation to the electronic component. When the temperature of the apparatus rises to a predetermined temperature, an increase in the angle between the surface of the ventilation area and the surface of the attachment area increases the ventilation to the electronic component and decreases the ventilation to the second circuit area, When the air temperature drops below a predetermined temperature, the airflow to the electronic component is reduced and the airflow to the second circuit area is increased by reducing the angle formed between the surface of the ventilation area and the surface of the mounting area. Is done.

  The board is housed in a housing, and the housing is provided with an air inlet, an air outlet, and a fan for ventilating the air from the air inlet to the air outlet in the housing.

  Further, the image forming apparatus GK includes a fixing device heated by a heater and a temperature control device that controls a fixing temperature in the fixing device. The temperature control device includes a semiconductor element for turning on / off power supply to the heater, a heater control circuit including a heat dissipation device for cooling the semiconductor element, and a ventilation for bringing the temperature control device into a ventilation state. Have means.

  In addition, the semiconductor element and the heat dissipation device are mounted on the first circuit area of the substrate, and the power supply circuit including the power transformer is mounted on the second circuit area, which is an area adjacent to the first circuit area of the substrate. When the temperature of the device rises to a predetermined temperature, an increase in the angle between the surface of the ventilation region and the surface of the mounting region increases the ventilation to the semiconductor element and decreases the ventilation to the second circuit region, When the air temperature drops below a predetermined temperature, the airflow to the semiconductor element is reduced and the airflow to the second circuit region is increased by reducing the angle formed between the surface of the ventilation region and the surface of the mounting region. Has been.

  A triac (bidirectional thyristor) is used as the semiconductor element. A shape memory alloy is used as the temperature sensitive deformation material.

  Next, the heat dissipation device HS will be described in more detail.

  FIG. 4 is a diagram showing a mounting configuration of the substrate device KS for a part of the control circuit SK, FIG. 5 is a diagram showing a mounting configuration of the substrate device KS when the temperature of the triac 5 rises, and FIG. FIG. 7 is a perspective view of the heat dissipation device HS when the temperature of the triac 5 is increased, and FIG. 8 is a view showing a substrate device KS of another embodiment.

  4 and 6 show a state before the temperature of the triac 5 is increased or a state where the temperature of the triac 5 is lowered to a predetermined temperature or lower.

  In FIG. 4, the substrate device KS includes a substrate 31, a housing 35 that accommodates the substrate 31, a fan 36, and the like.

  On the substrate 31, a heater circuit region HKR in which the heater circuit HK is mounted on the left side in FIG. 4 and a power circuit region DKR in which the power circuit DK is mounted on the right side are arranged.

  In the heater circuit region HKR, the above-described triac 5 is provided, and the triac 5 is provided with a heat radiating device (heat radiating plate) HS. A transformer 33 is provided in the power supply circuit region DKR.

  The housing 35 is formed in a box shape from metal or synthetic resin, and a lid is attached to the opening. The housing 35 is provided with an intake port 37 on its lower surface and an exhaust port 38 on its upper surface. A fan 36 is attached in the vicinity of the exhaust port 38. When the fan 36 is driven, air sucked from the intake port 37 flows through the housing 35 and is exhausted from the exhaust port 38.

  As shown in FIGS. 4 and 6, the triac 5 is soldered to the substrate 31, and the heat radiating device HS is attached to the triac 5 with a fixing screw 324.

  As described above, the heat dissipation device HS is formed in a rectangular plate shape using a shape memory alloy or the like. On one plate-like surface, an attachment region 321 for attaching the triac 5 is provided, and ventilation regions 322 and 323 for receiving ventilation are provided in a region continuous with the attachment region 321.

  The heat radiating device HS has a flat plate shape at room temperature, but has a shape memorized so as to have a shape as shown in FIGS. 5 and 7 when a high predetermined temperature TA2, for example, 90 ° C. is reached.

  That is, when the heat dissipation device HS becomes higher than a predetermined temperature, the angle θ formed by the surfaces of the ventilation regions 322 and 323 and the surface of the attachment region 321 increases. Specifically, when a predetermined temperature is reached, the ventilation regions 322 and 323 of the heat dissipation device HS are deformed to the transformer 33 side. As a result, the ventilation regions 322 and 323 receive more air flowing through the housing 35. Thereby, the ventilation to the triac 5 increases. At this time, instead of increasing the ventilation to the triac 5, the ventilation to the transformer 33 decreases.

  The angle θ1 formed by the ventilation region 322 and the attachment region 321 and the angle θ2 formed by the ventilation region 323 and the attachment region 321 may be the same or different.

  Next, operations and effects related to the heat dissipation device HS in the image forming apparatus GK will be described.

  When the image forming apparatus GK is powered on, power is supplied from the AC power source 1 to each unit, and the heater circuit HK and the power circuit DK are in an operating state. Thereby, the triac 5 and the transformer 33 generate heat, and the temperature in the substrate 31 and the housing 35 rises. Further, the fan 36 is driven, and the inside of the housing 35 enters a ventilation state. As a result, the triac 5 is maintained at a low predetermined temperature TA1, for example, about 80 ° C., and the transformer 33 is also maintained at a low predetermined temperature TB1, for example, about 80 ° C. In this state, the heat dissipation device HS is still in the state shown in FIGS.

  In this state, when the voltage of the AC power supply 1 decreases, the power supplied to the halogen lamp 3 decreases as it is as described above, and therefore the temperature control unit 27 performs control so that the on-time of the triac 5 increases. I do.

  By increasing the on-time of the triac 5, the amount of heat generated by the triac 5 increases and the temperature rises. When the temperature of the triac 5, that is, the heat dissipation device HS rises to a predetermined temperature TA2, the heat dissipation device HS has the ventilation regions 322 and 323 as transformers at the temperature TA2 as shown in FIGS. 5 and 7. Deforms to bend toward 33. Thereby, the area which the ventilation area | regions 322,323 receive a wind increases, a cooling effect is heightened, and the triac 5 is cooled more.

  On the other hand, as the voltage of the AC power supply 1 decreases, the temperature of the transformer 33 decreases. That is, with respect to the transformer 33, the temperature of the AC power supply 1 can be reduced due to a decrease in the voltage of the AC power supply 1.

  Therefore, the amount of ventilation to the triac 5 increases due to the deformation of the heat dissipation device HS due to the temperature rise of the triac 5 and the amount of ventilation to the transformer 33 decreases accordingly. Even if the amount decreases, there is no problem because the temperature is kept near the low predetermined temperature TB1.

  Thus, by using the heat dissipation device HS of the present embodiment, the temperature increase of the triac 5 when the voltage of the AC power supply 1 is reduced can be suppressed. Therefore, the triac 5 can be effectively used without increasing the surface area of the heat dissipating device HS or selecting a triac 5 having a large rated current, and without increasing the number of fans 36 or selecting a large fan. Can be cooled.

  As described above, according to this embodiment, it is possible to provide a heat dissipation device HS that has a simple structure, has a small number of parts, and can be easily downsized.

  Further, the substrate device KS can be reduced in size, and the air volume of the fan 36 can be suppressed, so that the noise can be reduced.

  When the temperature of the triac 5 falls below the predetermined temperature TA2, the heat dissipation device HS returns to the normal temperature shape shown in FIGS. 4 and 6, and the air flow rate is also in a steady state.

  In the heat dissipation device HS of the above embodiment, both the ventilation regions 322 and 323 are configured to be bent toward the transformer 33 when the heat dissipation device HS reaches a predetermined temperature TA2. However, as shown in FIG. 8, only one ventilation region 322 may be deformed so as to be bent toward the transformer 33.

  In addition, the relationship between the temperature and the shape of the heat dissipation device HS can be various in addition to those described above. For example, when the heat dissipation device HS reaches a predetermined temperature TA2, the ventilation region 322 may be deformed in a plurality of stages or in a round shape (curved surface).

  In the embodiment described above, the material, structure, shape, dimension, angle, attachment method, and the like of the heat dissipation device HS can be variously changed in addition to those described above. The shape, position, number, etc. of the heater circuit region HKR and the power supply circuit region DKR can be variously changed in addition to those described above.

  In addition, the structure, configuration, shape, arrangement, dimensions, number, material, etc. of the whole or each part of the heater circuit HK, the power supply circuit DK, the control circuit SK, the substrate device KS, or the image forming apparatus GK are in accordance with the spirit of the present invention. Can be changed as appropriate.

  In the embodiment described above, the heat radiating device HS of the substrate device KS provided in the image forming apparatus GK has been described as an example, but the present invention is for cooling electronic components in other types of substrate devices KS. It is possible to apply to.

1 is a diagram illustrating an overall configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a schematic configuration of a fixing device. 2 is a block diagram illustrating a part of a control circuit of the image forming apparatus. FIG. It is a figure which shows the mounting form of the board | substrate apparatus about a part of control circuit. It is a figure which shows the mounting form of the board | substrate apparatus when the temperature of a triac rises. It is a perspective view of the radiating device of a triac. It is a perspective view of a thermal radiation device when the temperature of a triac rises. It is a figure which shows the board | substrate apparatus of other embodiment.

Explanation of symbols

1 AC power supply 3 Halogen lamp 4 Control unit 5 Triac (electronic component, semiconductor element)
27 Temperature control unit (Temperature control unit)
31 Substrate 321 Mounting region 322, 323 Ventilation region 33 Transformer 35 Housing 36 Fan 37 Air inlet 38 Air outlet GK Image forming device F Fixing device f1 Fixing roller SK Control circuit KS Substrate device (electronic substrate device)
HK heater circuit DK power supply circuit HKR heater circuit area (first circuit area)
DKR power circuit area (second circuit area)
HS Heat dissipation device (heat sink)

Claims (5)

An electronic board device arranged in a ventilated atmosphere,
A semiconductor element and a heat dissipation device for turning on and off the power supply are mounted on the first circuit region of the substrate,
A power circuit including a power transformer is mounted on a second circuit region, which is a region adjacent to the first circuit region on the substrate,
When the amount of heat generated in the first circuit area increases, the amount of heat generated in the second circuit area decreases,
The heat dissipation device
Formed in a plate shape by a temperature-sensitive deformable material whose shape changes according to temperature change, and on one surface thereof, a mounting region for mounting the semiconductor element and a region continuous to the mounting region for receiving ventilation A ventilation area,
When the temperature rises to a predetermined temperature, an angle formed between the surface of the ventilation region and the surface of the mounting region increases, so that the ventilation region receives more ventilation and increases ventilation to the semiconductor element . Is composed of
When the heat dissipation device rises to a predetermined temperature, an increase in the angle between the surface of the ventilation region and the surface of the mounting region increases the ventilation to the semiconductor element and the ventilation to the second circuit region. Reduce
When the heat dissipation device falls below a predetermined temperature, a reduction in the angle formed between the surface of the ventilation region and the surface of the attachment region reduces the ventilation to the semiconductor element and leads to the second circuit region. Configured to increase ventilation,
An electronic substrate device characterized by that. The substrate is housed in a housing;
In the housing, an intake port, an exhaust port, and a fan for ventilating from the intake port toward the exhaust port in the housing,
The electronic substrate device according to claim 1, further comprising: The semiconductor element is a bidirectional thyristor,
The temperature sensitive deformation material is a shape memory alloy,
The electronic substrate device according to claim 1 or 2. An image forming apparatus having a fixing device heated by a heater and a temperature control device for controlling a fixing temperature in the fixing device,
The temperature control device includes:
A semiconductor element for turning on and off the supply of electric power to the heater, a heater control circuit including a heat dissipation device for cooling the semiconductor element, and a ventilation means for allowing the temperature control apparatus to enter a ventilation state Have
The heat dissipation device
Formed in a plate shape by a temperature-sensitive deformable material whose shape changes according to temperature change, and on one surface thereof, a mounting region for mounting the semiconductor element and a region continuous to the mounting region for receiving ventilation A ventilation area,
When the heat dissipation device rises to a predetermined temperature, an angle formed between the surface of the ventilation region and the surface of the attachment region increases, whereby the ventilation region receives a larger amount of ventilation and ventilates the semiconductor element. It is configured to increase the,
The semiconductor element and the heat dissipation device are mounted in a first circuit region on the substrate,
A power circuit including a power transformer is mounted on a second circuit region, which is a region adjacent to the first circuit region on the substrate,
When the heat dissipation device rises to a predetermined temperature, an increase in the angle between the surface of the ventilation region and the surface of the mounting region increases the ventilation to the semiconductor element and the ventilation to the second circuit region. Reduce
When the heat dissipation device falls below a predetermined temperature, a reduction in the angle formed between the surface of the ventilation region and the surface of the attachment region reduces the ventilation to the semiconductor element and leads to the second circuit region. Configured to increase ventilation,
An image forming apparatus. The semiconductor element is a bidirectional thyristor,
The temperature sensitive deformation material is a shape memory alloy,
The image forming apparatus according to claim 4 .

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