JP3139933B2 - Electric cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric cooker such as an electric rice cooker for cooking by a radiant heating method using a heater such as a halogen heater for generating electromagnetic waves.

[0002]

2. Description of the Related Art As a conventional electric rice cooker, as shown in FIG. 7, a heating plate 3 made of an aluminum casting or the like having a high heat conductivity and having a sheathed heater 2 embedded therein is provided in a rice cooker main body 1. Some rice cookers heat the inner pot 4 placed on the heating plate 3 to cook rice. In FIG. 7, reference numeral 5 denotes a lid which is freely openable and closable on the rice cooker main body 1, reference numeral 6 denotes a packing for sealing a gap between the lid 5 and the inner pot 4, and reference numeral 7 denotes a holder 8 in the rice cooker main body 1. , 9 and 10 are heat-retaining heaters, 11 is a heat-sensitive element having a heat-sensitive element 12 for detecting the temperature of the inner pot 4, and 13 is a power cord reel for winding and storing a power cord.

However, in this type of rice cooker, the heating plate 3 is heated by the heat of the sheath heater 2 and the inner pot 4 is thereby heated. The time gets longer,
Responsiveness was poor, and fine temperature control was difficult.

Therefore, in recent years, a radiant heating type rice cooker has been proposed in which rice cooking performance is improved by using a heat source such as a halogen heater that generates an electromagnetic wave. However, halogen heaters are generally not as robust as sheathed heaters, and have the problem of corrosion and deterioration due to foreign matter adhesion. Therefore, in a rice cooker using a halogen heater, as shown in FIG. 8, a protective plate 17 made of glass that transmits electromagnetic waves is disposed between the inner pot 15 and the halogen heater 16, so that foreign substances to the halogen heater 16 can be prevented. Prevention of adhesion. In FIG. 8, 1
Reference numeral 8 denotes a heat-sensitive body that detects the temperature of the inner pot 15 that is arranged so as to penetrate the center of the protection plate 17.

[0005]

In a conventional radiant heating rice cooker using a halogen heater or the like, a heat-sensitive body 1 is used.
8 is disposed through the center of the protection plate 17,
Electromagnetic waves from the halogen heater 16 were blocked by the heat-sensitive body 18, and heating near the bottom center of the inner pot 15 was insufficient, causing uneven heating. Further, if the heat shielding of the thermosensitive body 18 is not sufficiently performed, the temperature of the inner pot 15 cannot be accurately detected due to the influence of the radiant heat and the conductive heat of the halogen heater 16, and it is not sufficient to perform the accurate temperature detection. There was a problem that cost would increase if appropriate measures against heat insulation were taken.

On the other hand, Japanese Patent Laying-Open No. 6-327552 discloses a rice cooker having a structure in which a temperature sensor for detecting the temperature of an inner pot is disposed at a position avoiding the protective plate. When the inner pot is heated by the heater, the temperature sensor does not interfere, and the influence of the radiant heat or conduction heat of the halogen heater in the temperature sensor can be reduced.

However, since the inside of the bottom of the inner pot is heated strongly, there is a risk of uneven cooking. Further, since the protection plate is supported only at its outer peripheral portion, its strength against external force is weak at a central portion distant from the outer peripheral portion. When the hook is attached, there is a risk that the protection plate may be cracked or cracked by an external force when a foreign substance or the like is pushed in by the bottom of the inner hook.

If the protective plate is dirty and the transmittance of electromagnetic waves from the halogen heater is poor, the surface temperature of the normal protective plate is about 600 to 700 ° C., whereas the surface temperature is 800 ° C. or more. . In such a state, the heating efficiency deteriorates, and in the worst case, each member inside may be deformed or melted. Further, when the reflection plate for reflecting the electromagnetic wave from the halogen heater in the inner pot direction is dirty or fogged and the reflection efficiency of the electromagnetic wave is reduced, the surface temperature of the normal reflection plate is about 400 to 450 ° C. , The surface temperature becomes 500 ° C. or higher. In such a state, the heating efficiency deteriorates, and in the worst case, the reflection plate itself may be deformed or melted. JP-A-6
In Japanese Patent No. 327552, no safety measures are taken against abnormal heating of the protection plate and the reflection plate, and the safety is lacking. As described above, the radiant heating rice cooker using the conventional halogen heater or the like has a problem in practicality in terms of uniform heating of the inner pot, safety measures, and the like.

[0009] In view of the above, an object of the present invention is to provide a practical electric cooker that can enhance safety and uniformly heat a cooking section.

[0010]

As shown in FIGS. 1, 2 and 3, a means for solving the problem according to the present invention is arranged such that a cooking section 22 provided inside a cooking device body 20 and a space between the cooking section 22 are provided. A heater 37 for generating electromagnetic waves (light);
And a protection plate 38 disposed between the heating heater 37 and the electromagnetic wave from the heating heater 37. The protection plate 38 includes:
The outer peripheral part and the central part are supported by a supporting body that is a reflecting plate 40, and the transmittance of electromagnetic waves increases as the distance from the heater 37 increases, and the temperature detecting unit 50 that detects the temperature of the cooking unit 22 includes a protective plate 38. Are arranged at positions avoiding the above. The support of the central portion of the protective plate 38 by the reflective plate 40 means that the reflective plate 40 is supported by contacting the central portion of the protective plate 38 and that the reflective plate 40 is separated from the central portion of the protective plate 38. When the protection plate 38 is bent by an external force (for example, when the cooking unit 22 is mounted in a state where a foreign object or the like is placed on the protection plate 38 and a foreign object or the like is pushed in the cooking unit 22). This is a concept that includes a member that is supported by being in contact with the reflection plate 40.

Further, a protection plate temperature detecting portion 51 for detecting the temperature of the protection plate 38 and a reflection plate temperature detection portion 52 for detecting the temperature of the reflection plate 40, and the temperature of the protection plate 38 and the reflection plate 40 are not lower than the set temperature. In this case, a control unit 60 for stopping the power supply to the heater 37 is provided.

Further, the heater 37 is disposed in the heater storage chamber 41 surrounded by the protection plate 38 and the reflection plate 40, and is disposed outside the heater storage chamber 41 through the reflection plate 40 of the heater 37. The part is light-shielded.

[0013]

In the above-mentioned means for solving the above problems, the food is put into the cooking section 22, and the cooking section 22 is mounted on the cooker main body 20.
At this time, even if a foreign object or the like placed on the protection plate 38 is pushed by the cooking device 22 and an external force is applied to the protection plate 38, the protection plate 38 has a strong strength against the external force because the central portion and the outer peripheral portion thereof are supported. It does not break or break. When cooking is started, light is emitted from the heater 37, and this light is transmitted directly or reflected by the reflection plate 40 and transmitted through the protection plate 38. At this time, the strong light reaching the position near the heater 37 is attenuated and transmitted due to the difference in transmittance of the protection plate 38, and the weak light reaching the position far from the heater 37 is transmitted without being attenuated. Thereby, the intensity of the light transmitted through the protection plate 38 becomes uniform, reaches the cooking unit 22 and uniformly radiates and heats the cooking unit 22. Then, cooking is performed by controlling the energization of the heater 37 in accordance with the temperature of the cooking unit 22 detected by the temperature detection unit 50. At this time, since the temperature detection unit 50 is disposed at a position avoiding the protection plate 38, when the heating unit 37 heats the cooking unit 22, the temperature detection unit 50 does not hinder the heating efficiency and improves the heating efficiency. Heating becomes possible.

If the protection plate 38 is dirty during cooking and the light transmittance is low, the temperature of the protection plate 38 rises abnormally. In this case, the heating efficiency of the cooking unit 22 deteriorates, and in the worst case, each member in the cooking device body 20 may be deformed or melted. Therefore, by detecting that the temperature of the protection plate 38 has become equal to or higher than the set temperature T1 by the protection plate temperature detection unit 51, the power supply to the heater 37 is stopped to ensure safety.

Further, if the reflection plate 40 is dirty or cloudy and the light reflection efficiency is low, the temperature of the reflection plate 40 may rise abnormally. Therefore, by detecting that the temperature of the reflector 40 has become equal to or higher than the set temperature T2 by the reflector temperature detector 52, the power supply to the heater 37 is stopped to ensure safety.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, an electric rice cooker as an electric cooker according to one embodiment of the present invention has a short cylindrical outer case 20a.
A cooker body (cooker body) 20 having an outer shell formed from a bottom case 20b engaged and fixed to a lower end portion of an outer case 20a, and an openable and closable lid 21 covering an upper surface opening thereof
In the rice cooker main body 20, an inner pot 22 as a cooking unit is detachably mounted.

The lid 21 is rotatably supported on the rice cooker main body 20 around a pivot and forms an outer shell of the lid 21, and an inner pot 22 attached to the inside of the outer lid 25. And an inner lid 26 that covers the upper surface opening of the inner cover 26.

The outer lid 25 is provided with a rubber packing 27 for sealing a gap between the inner lid 26 and the upper end of the inner pot 22. This packing 27 is put on the outer periphery of an annular packing holder 29 fixed with screws 28 in an annular groove 25 a formed on the lower surface of the outer lid 25, and the upper end is in contact with the lower surface of the outer lid 25 and the packing holding member. It is sandwiched between the upper surface of the tool 29 and formed in a loop shape in a sectional view without a gap to enter from the outside. Accordingly, deterioration can be prevented without accumulating water or the like inside the packing 27, and only the surface of the packing 27 needs to be cleaned, so that the cleaning property is improved.

The outer lid 25 and the inner lid 26 are formed with a steam hole 30 vertically penetrating therethrough.
Is filled with a heat insulating material, and a heat retaining heater 31 is provided on the upper surface of the inner lid 26 to perform a heat retaining function.

In the rice cooker main body 20, an inner case 36 for accommodating the inner pot 22, a heater (halogen heater) 37 disposed below the inner pot 22, and an inner pot 22 and a halogen heater 37 are provided. A protection plate 38 that is interposed therebetween and transmits electromagnetic waves from the halogen heater 37 is provided.

The inner pot 22 has a short cylindrical shape with a bottom and a semi-spherical bottom with a flat or slightly concave bottom, and is made of a metal having high thermal conductivity, heat resistance and impact resistance, such as aluminum or an aluminum alloy. It is used as a base material, and its inner surface is coated with a fluorine-based resin to enhance the cleaning property.

The inner case 36 has a short cylindrical shape, and the inner surface thereof is a reflecting plate made of aluminum or aluminum alloy or the like having a specular gloss with good reflection efficiency.
The upper end is held by the rice cooker main body 20 via a holder 39. The inner pot 22 has its upper end placed on the holder 39 and is housed with a gap around the inner case 36.
The electromagnetic wave from 7 is reflected on the outer periphery of the inner pot 22.

The halogen heater 37 is made of a heating element that generates an electromagnetic wave including a wavelength in the range from visible light to far infrared rays. The halogen heater 37 is formed in a ring shape and is surrounded by a protective plate 38 and a reflective plate 40 described later. It is held by a heater holder 42 at the center of the heater storage chamber 41.

As shown in FIGS. 2 and 3, the protective plate 38 is formed in a disc shape using heat-resistant crystallized glass. As the distance from the halogen heater 37 increases, the transmittance of electromagnetic waves increases. Set to large. Here, the reason for changing the transmittance of the electromagnetic wave will be described. Generally, the temperature distribution of the inner pot 22 due to heating depends on the thickness of the inner pot 22, the distance between the halogen heater 37 and the inner pot 22, the halogen heater 3
7, the thickness of the protection plate 38, the transmittance of the protection plate 38 for electromagnetic waves, and the like. Among them, the distance between the halogen heater 37 and the inner pot 22 has the highest influence, the area directly above the halogen heater 37 is most easily heated, and the further the distance from the halogen heater 37, the more difficult it is to heat. Since the uneven temperature distribution leads to uneven cooking, it is desirable to make the temperature distribution uniform, that is, to heat the inner pot 22 uniformly. Therefore, by changing the transmittance of the electromagnetic wave in the protection plate 38 as described above,
The intensity of the electromagnetic wave reaching the inner pot 22 is made uniform to make the inner pot 22 uniform.
Receive uniform radiant heat to achieve uniform heating.

The transmittance of the electromagnetic wave in the protection plate 38 is set by disposing a high-temperature ceramic ink or the like, which attenuates the electromagnetic wave to lower the transmittance, around a portion of the protection plate 38 immediately above the halogen heater 37. Is made by printing in a ring shape so that the film thickness becomes thinner as the distance increases. That is, the film thickness of one printing is 1
The printing is performed once at the proximity position A relatively close to the halogen heater 37 and the printing is performed once more, that is, twice, at the position B immediately above the halogen heater 37 at about μm. FIG. 4 shows the relationship between the film thickness of printing and the transmittance of electromagnetic waves, where the thinner the film thickness, the higher the transmittance of electromagnetic waves.

A reflection plate 40 is disposed below the protection plate 38. The reflection plate 40 has a semicircular curved surface formed in a ring shape, and its upper end 40a is in contact with the lower surface of the protection plate 38. It is bent so as to surround the outer peripheral portion of the protection plate 38. Moreover, the central upper end 40b of the reflection plate 40
Is in contact with the lower surface center of the protection plate 38, whereby the protection plate 38 is supported from below by a reflector 40, the outer periphery and the center of which are supported by an external force (the protection plate 38). The inner pot 22 is mounted in a state where the foreign substance or the like is placed on the upper part, and the strength against the force applied when the foreign substance or the like is pushed in at the bottom of the inner pot 22 is increased. In addition,
The central upper end 40b of the reflecting plate 40 is disposed at a distance of about 0.5 mm below the center of the lower surface of the protective plate 38, and when an external force is applied to the protective plate 38 from above, the protective plate 38 slightly bends and reflects. The support structure may be configured to abut on the upper end 40b of the center of the plate 40. In this case, the external force can be absorbed by a slight bending of the protection plate 38.

The lower end of the inner case 36 is in contact with the outer peripheral portion of the upper surface of the protective plate 38. The lower surface opening of the inner case 36 is closed by the protective plate 38, and dust and foreign matter spilled from the inner pot 22 are removed. To the halogen heater 37 is prevented. Note that a seal may be provided between the outer peripheral portion of the protective plate 38 and the outer peripheral upper end 40a of the reflective plate 40 so that water or the like does not enter the heater storage chamber 41 from the outer peripheral portion of the protective plate 38.

The reflection plate 40 is fixed to a cover 42 having a heat insulating function for covering the reflection plate 40 by screws or the like. A plate-like angle for mounting a sensor is provided between the cover 42 and the rice cooker main body 20. 43 are handed over. Then, the above-described halogen heater 37, protection plate 38, reflection plate 4
0 and the cover 42 are integrated into a heater unit 45, and the heater unit 45 is
Is mounted on the bottom of the rice cooker main body 20 to be supported. The mouth sealing portion 37 of the halogen heater 37
It is necessary to place a at about 250 ° C. or lower so that the welded portion does not melt. However, since the temperature in the heater storage chamber 41 is about 400 ° C., the mouth sealing portion 37 a is Must be located externally. For this reason, the mouth sealing portion 37 a of the halogen heater 37 is disposed outside the heater unit 45 through the reflection plate 40 and the cover 42. In this case, the rice cooker body 20 not directly related to the rice cooker 20 due to the electromagnetic waves leaking from the mouth sealing portion 37a.
Each of the internal members may be heated and adversely affected, or the electromagnetic waves may leak to the outside of the rice cooker main body 20. Therefore, in this embodiment, safety measures such as solving the above-described problem are taken by covering the mouth sealing portion 37a of the halogen heater 37 disposed outside the heater unit 45 with the terminal cap 46 having a light shielding property. I have.

At a position where the protection plate 38 of the angle 43 is avoided, a temperature detecting portion (thermosensitive body) 50 having a thermosensitive element such as a thermistor for contacting the inner pot 22 and detecting the temperature of the inner pot 22 penetrates. Held, and the outer peripheral upper end 40a of the reflector 40
A protection plate temperature detector 5 composed of a thermistor for detecting the temperature of the protection plate 38 is provided on the outer peripheral portion of the lower surface of the protection plate 38 surrounded by
1 is provided on the lower surface of the reflector 40, and a reflector temperature detector 5 composed of a thermistor for detecting the temperature of the reflector 40 is provided.
2 are installed.

Further, inside the rice cooker main body 20, a lid 21 is provided.
A lid open / close detection unit 53 is provided which is an on / off switch which is turned on / off by a projection 25a projecting from the front lower surface of the outer lid 25 coming into contact with or separating from the front lid 25 in accordance with the opening / closing operation of the outer lid 25. On the other side of the inner pot 22,
An inner hook presence / absence detector 54, which is an optical sensor for detecting whether the inner hook 22 is housed in the inner case 36, is attached.

In front of the rice cooker main body 20, there is provided a microcomputer for executing the rice cooking process shown in FIG. 5, which comprises a preheating step, a rice cooking step, a washing step, and a warming step, based on output signals from the respective detectors. A control unit 60 is provided. The control unit 60 includes a lid opening / closing detection unit 53 that detects the opening of the lid 21 and an inner hook presence / absence detection unit 54.
When the non-attachment of the inner pot 22 is detected, the first safety function of stopping the energization of the halogen heater 37 and the temperature of the protection plate 38 detected by the protection plate temperature detection unit 51 abnormally rises, and When the temperature exceeds the allowable temperature T1 (for example, 800 ° C.), the second safety function of stopping the energization of the halogen heater 37, and the temperature of the reflector 40 detected by the reflector temperature detector 52 abnormally rises to allow the safety. A third safety function is provided in which the power supply to the halogen heater 37 is stopped when the temperature becomes equal to or higher than the temperature T2 (for example, 500 ° C.).

In FIG. 1, reference numeral 61 denotes a power cord reel for winding and storing the power cord, and reference numeral 62 denotes a heat retaining heater attached to the inner case 36.

The operation of the rice cooking process in the above configuration will be described with reference to FIGS. First, a predetermined amount of washed rice and water are put into the inner pot 22, the inner pot 22 is housed in the inner case 36, the lid 21 is closed, and a rice cooker switch (not shown) is pressed to cook rice. To start. At this time, if the lid 21 is not closed or the attachment of the inner pot 22 is incomplete, the halogen heater 37 is not energized, and a notification unit (not shown) such as a lamp notifies the user of the abnormality. . If the lid 21 is not closed, the electromagnetic wave (light) from the halogen heater 37 is emitted to the outside of the rice cooker main body 20 and enters the eyes, which may hurt the eyes. If you start cooking rice without having
Since there is a risk that the resin of the holder 39 and the inner lid 26 may be melted, the rice cooking operation is performed only when the inner pot 22 is completely attached and the lid body 19 is tightly closed in order to prevent these. Have started.

When the rice cooking operation is started, a preheating step for allowing the rice to sufficiently absorb water is performed.
Emits light having a color temperature of about 2300 to 2500 K,
This light is reflected directly or by the reflection plate 40 and the protection plate 3
8 is transmitted. At this time, the strong light reaching the position B immediately above the halogen heater 37 is attenuated and transmitted by the difference in transmittance of the protection plate 38, and the halogen heater 37.
The light that has arrived at the proximity position A relatively close to the light source is slightly attenuated and transmitted, and the other weak light that has reached the position far from the halogen heater 37 is transmitted without being attenuated. This allows
The intensity of the light transmitted through the protection plate 38 becomes uniform, reaches the inner pot 22 directly or reflected by the inner case 36, and uniformly radiates and heats the inner pot 22.

The preheating step is performed when the temperature of rice and water is 60 ° C. or less. This is because when the temperature of the rice reaches 60 ° C. or higher, gelatinization starts and the rice does not absorb water. Therefore, the energization of the halogen heater 37 is controlled so that the temperature of the inner pot 22 detected by the thermosensitive body 50 does not exceed 60 ° C.

When the preheating step is completed (water absorption of rice is completed), the process proceeds to the rice cooking step, in which rice is cooked in a heating sequence according to the rice cooking capacity. The steam generated by the rise in the temperature of the cooked water is discharged outside through the steam holes 30 of the outer lid 25 and the inner lid 26. As the rice cooking progresses, the water in the inner pot 22 disappears and the bottom temperature of the inner pot 22 becomes 10
When the temperature rises rapidly to 0 ° C. or higher and the thermosensitive body 50 detects this,
The energization of the halogen heater 37 is stopped, and the rice cooking process ends. At this time, the inner pot 22 is uniformly heated, and it is possible to obtain delicious cooked rice without uneven cooking.

If the protection plate 38 is dirty during the rice cooking process and the light transmittance is poor, the temperature of the protection plate 38 rises abnormally, the heating efficiency of the inner pot 22 deteriorates, and in the worst case, There is a risk that the holder 39 and the outer case 20 may melt. Therefore, when the protection plate temperature detecting section 51 detects that the temperature TA of the protection plate 38 has become equal to or higher than the safety allowable temperature (800 ° C.) T1, the power supply to the halogen heater 37 is temporarily or permanently stopped to prevent the safety. Is secured.

Further, if the reflection plate 40 is dirty or fogged and the light reflection efficiency is low, the temperature of the reflection plate 40 rises abnormally, and in the worst case, the reflection plate 40 itself may be melted. is there. Therefore, the reflection plate temperature detector 52
And the temperature TB of the reflector 40 becomes the safe allowable temperature T2 (500
° C) or more, the power supply to the halogen heater 37 is temporarily or permanently stopped to ensure safety.

When the rice cooking process is completed, the process proceeds to the washing process, in which the halogen heater 37 is energized so that the temperature of the inner pot 22 detected by the thermosensitive element 50 does not exceed 98 ° C. and is maintained for about 20 minutes. The heating is performed by heat conduction because there is almost no water in the inner pot 22 and the cooked rice is completely pregelatinized. When the temperature of the inner pot 22 is detected to have risen by the heat sensing element 50, the halogen heater 3 is turned on.
The power supply to 7 is stopped, and the rice cooking is completed.

Thereafter, when the heat sensing element 50 detects that the temperature of the inner pot 22 has dropped to the heat retaining temperature, the heat retaining heater 31 of the inner lid 26 and the heat retaining heater 62 of the inner case 36 are provided.
And the rice cooked in the inner pot 22 is kept warm at about 73 ° C., and the rice cooking process is completed.

As described above, since the protective plate 38 is supported at the outer peripheral portion and the central portion by the reflector 40, the strength of the protective plate 38 with respect to the external force is increased as compared with the conventional structure in which only the outer peripheral portion is held. Protection plate 38
The inner pot 22 is attached with the foreign matter, etc.
The protection plate 38 can be prevented from being damaged (for example, cracked) or cracked when a foreign substance or the like is pushed into the bottom of the device, and the reliability and safety can be improved.

Since the protection plate 38 is set so that the transmittance of the electromagnetic wave increases as the distance from the halogen heater 37 increases, the intensity of the electromagnetic wave (light) transmitted through the protection plate 38 becomes uniform, and The pot 22 can be uniformly heated, and delicious cooked rice without uneven cooking can be obtained.

In addition, since the heat sensitive body 50 is disposed at a position avoiding the protective plate 38, the electromagnetic wave reaches the central portion without obstructing the heat sensitive body 50 when the inner heater 22 is heated by the halogen heater 37. In addition, the heating efficiency can be improved and uniform heating can be performed.
7, the temperature of the inner pot 22 can be accurately detected by reducing the heat influence (radiant heat and conduction heat), and furthermore, the heat shielding measures in the heat sensitive body 50 can be reduced to reduce the cost. Since the body 50 is eliminated, the cleaning property of the surface of the protection plate 38 is also improved.

Also, if the lid 21 is not closed,
When it is detected that the inner pot 22 is not mounted or incompletely mounted, the halogen heater 37 is not energized and the protection plate 3
Since the power supply to the halogen heater 37 is stopped upon detecting that the temperature of the reflector 8 or the reflection plate 40 has become equal to or higher than the safety allowable temperature (abnormal rise in temperature), the safety is further improved.

Further, since the mouth sealing portion 37a of the halogen heater 37 disposed outside the heater unit 45 is covered with the terminal cap 46 having a light-shielding property, the rice cooker main body is exposed to electromagnetic waves from the mouth sealing portion 37a. It is possible to enhance the safety by eliminating the adverse effects such as the heating of the members inside the electronic device 20 and the leakage of the electromagnetic waves to the outside of the rice cooker main body 20.

It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that many modifications and changes can be made to the above-described embodiment within the scope of the present invention. For example, the electric cooker of the present invention is not limited to an electric rice cooker, but may be a grill pan or a hot plate. The setting of the transmittance of the electromagnetic wave in the protection plate may be performed by changing the type and density of the ink to be printed, or by changing the thickness of the protection plate.

[0047]

As is clear from the description above, according to the present invention, according to the present onset bright, since the protective plate is supported at its outer peripheral portion and the central portion, the protection compared to the structure that holds only the outer peripheral portion as in the prior art The strength against external force of the plate can be increased, and the cooking part is mounted with foreign matter etc. on the protection plate, preventing damage and cracking of the protection plate when foreign matter etc. is pushed in the cooking part. As a result, reliability and safety can be improved.

Further, since the temperature detecting portion is disposed at a position avoiding the protective plate, the electromagnetic wave reaches the entire protective plate without disturbing the temperature detecting portion when the cooking portion is heated by the heater. Improved heating efficiency and uniform heating are possible, reducing the thermal effects (radiant heat and conduction heat) by the heater of the temperature detection unit, enabling accurate detection of the temperature of the cooking unit. The cost can be reduced by reducing the heat shielding measures, and since there is no temperature detecting portion, the cleanability of the protection plate is also improved.

[0049] Then, by detecting that the temperature of the protective plate and the reflection plate is equal to or greater than the set temperature, for stopping the energization of the heater, the electromagnetic wave transmittance and reflection due to contamination or the like of the protective plate and the reflection plate It is possible to prevent the efficiency from deteriorating, and prevent the temperature of the protection plate and the reflection plate from abnormally rising and thereby deforming and melting each member in the cooking device main body, thereby further improving safety.

[0050] Further, since the outside arranged portion of the heater housing chamber through the reflection plate in the heater is blinded, each member of the internal cooking device body by electromagnetic waves from disposed portion in the external Safety can be improved by eliminating adverse effects such as heating and leakage of electromagnetic waves to the outside of the cooking device main body.

[0051]

[Brief description of the drawings]

FIG. 1 is a sectional view of an electric rice cooker according to one embodiment of the present invention.

FIG. 2 is a bottom view of the protection plate.

FIG. 3 is a partial sectional view of a heater unit.

FIG. 4 is a diagram showing a relationship between a printing film thickness and transmittance.

FIG. 5 is a flowchart of a rice cooking process.

FIG. 6 is an operation flowchart for a temperature rise of a protection plate and a reflection plate.

FIG. 7 is a sectional view of a conventional electric rice cooker.

FIG. 8 is a sectional view of another conventional electric rice cooker.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 20 Cooker main body 22 Cooking part 37 Heater 38 Protection plate 40 Reflection plate 41 Heater storage room 50 Temperature detection part 51 Protection plate temperature detection part 52 Reflection plate temperature detection part 60 Control part

Continued on the front page (72) Inventor Kiyohide Tameike 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (72) Inventor Takao Murai 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Sharp Corporation (56 References JP-A-6-327552 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) A47J 27/00 103 F24C 7/08 320 H05B 3/00 330 F24C 7/04 301

Claims (6)

(57) [Claims] 1. A cooking unit provided inside a cooking device main body, a heater for generating electromagnetic waves arranged at an interval in the cooking unit, and a heater disposed between the cooking unit and the heater. Wherein the outer peripheral portion and the central portion of the protective plate are supported by a support, and a temperature detector for detecting the temperature of the cooking portion avoids the protective plate. An electric cooker, wherein the electric cooker is arranged at a predetermined position. 2. The electric cooker according to claim 1, wherein a reflector that reflects electromagnetic waves from the heater toward the cooking section is used as a support. 3. A protection plate temperature detection unit for detecting a temperature of the protection plate, and a control unit for stopping power supply to the heater when the temperature of the protection plate becomes equal to or higher than a set temperature. The electric cooker according to claim 1. 4. A reflector for reflecting an electromagnetic wave from the heater toward the cooking section, a reflector temperature detector for detecting the temperature of the reflector, and a heater when the temperature of the reflector becomes equal to or higher than a set temperature. The electric cooker according to claim 1, further comprising a control unit configured to stop energization of the electric cooker. 5. A heater is disposed in a heater storage chamber surrounded by a protection plate and a reflection plate, and a portion of the heater that passes through the reflection plate and is disposed outside the heater storage chamber is shielded from light. The electric cooker according to claim 2 or 4, wherein: 6. The heater, protection plate and support are integrated.
2. The unit as claimed in claim 1, wherein
Electric cooker.