JPH078372A - Rice cooker - Google Patents

Abstract

PURPOSE:To prevent the surface of cooked rice from drying and prevent dripping of drops of water during keeping warm by controlling the detected temp. of the temp. detecting device of the lid so as to keep higher than that of keeping the receptacle warm. CONSTITUTION:The heater 16 of the drum is electrically contolled so that the heater 15 for cooking rice is always off and the detected temp. of the receptacle sensor 18 keeps 71 deg.C through the warmth keeping device during the process of keeping warm. And the heater 17 for the lid is controlled so that the detected temp. of the sensor 22 of the lid keeps higher than that of warmth keeping by 0.5 deg.C only during the heater 16 of the drum is on. When the temp. of the lower plane 10 of the lid rises by turning on the heater 16 of the drum, drops of water condensed on the lower plane 10 of the lid vaporize so that the problem of boiled rice to become soggy is prevented. When the room temp. is low and the time for controlling the heater 17 for the lid becomes long, the dew formation due to the temp. drop of the lower plane of the lid is prevented. When the room temp. is high, the time for controlling the heater 17 for the lid becomes short, and drying of cooked rice due to overheating of the lower plane of the lid is also prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rice cooker in which the lower surface of a lid is heated during heat retention to prevent dew condensation on the lower surface of the lid, and in particular, uneven drying on the surface of rice due to excessive heating is prevented or Regarding the improved rice cooker.

[0002]

2. Description of the Related Art Conventionally, this type of rice cooker stores rice and water to be cooked in a container, closes an upper opening of the container with a lid, and then controls a rice heater to turn on and off. To heat the container to cook hot water and main rice. Then, when the temperature detected by the container sensor that detects the temperature of the container reaches the predetermined cooking temperature, the rice cooking heater is turned off, the rice cooking process is completed through the unevenness, and then the temperature detected by the container sensor is the predetermined heat retention temperature. When the temperature drops to, the lid heater is controlled to switch on and off so that the temperature of the lower surface of the lid is maintained at, for example, 71 ° C., which is slightly higher than the temperature of the rice in the container.

[0003]

In the above-mentioned conventional rice cooker, since the lower surface of the lid is always set higher than the rice temperature, dew condensation on the lower surface of the lid can be prevented, but about 12 hours. When the temperature is kept for a long time, the upper surface of the rice is likely to be yellowed due to the Maillard reaction, and the unevenness of drying and yellowing of the rice occurs due to the temperature change of the lower surface of the lid. In particular, in order to improve the appearance and cleanability of the lower surface of the lid body, in the case of a type of rice cooker that directly heats rice from the lower surface of the lid body without providing a separate inner lid on the lower surface of the lid body, Since the heat from the heater is directly radiated to the upper surface of the rice via the lower surface of the lid, such a phenomenon becomes more remarkable.

On the other hand, a lid heater set by controlling a predetermined amount of duty ratio, or a lid heater having a predetermined power consumption is interlocked with the on / off state of the warming heater for warming control so that the lower surface of the lid body is closed. Heating may be considered. However, in a rice cooker having such a structure, there is no means for controlling the temperature of the lower surface of the lid. Condensation may form on the lower surface of the body, and rice may dry or yellow.

In view of the above problems, it is an object of the present invention to provide a rice cooker capable of preventing the upper surface of rice from being dried and drip dripping during heat retention under any circumstances.

[0006]

The present invention provides a container, a container heating means for heating the container, a container temperature detecting means for detecting the temperature of the container, and a container temperature detecting means for detecting the temperature of the container. Insulation control means for keeping the container warm at a predetermined temperature by cutting off the container heating means, a lid for covering the upper opening of the container, a lid heating means for heating the lower surface of the lid, and the lid. Lid temperature detecting means for detecting the temperature of the lower surface, and detection of the lid temperature detecting means so that the temperature of the lower surface of the lid body becomes higher than the heat retaining temperature of the container by the heat retaining control means during energization of the container heating means. Lid heating control means for controlling heating of the lid heating means based on temperature.

[0007]

According to the above construction, the temperature of the lid heating means is controlled by the lid heating control means such that the temperature of the lower surface of the lid is higher than the temperature for keeping the container warm only while the container heating means is being energized by the temperature keeping control means. Is performed. Therefore, the heating temperature of the lower surface of the lid during the heat retention process repeats a change that becomes higher or lower than the rice temperature in the container in accordance with the power interruption of the container heating means.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In FIG. 1 showing a cross-sectional view of a rice cooker, reference numeral 1 denotes a bowl main body having an open upper surface, and the bowl main body 1 includes an inner case 2 made of aluminum and an outer case 3 made of resin.
A heat insulating material 4 such as glass wool is provided between the inner case 2 and the outer case 3. Also,
A reflection plate 5 made of aluminum is provided at the bottom of the inner case 2, and a bottomed cylindrical container 6 having an open upper surface is located above the reflection plate 5 and can be inserted into and removed from the inner case 2. Be accommodated. Reference numeral 7 denotes a lid, and an outer lid 8 for opening and closing the upper opening of the container body 1, a lid frame 9 provided below the outer lid 8, and a lid for directly covering the upper opening of the container 6. 7, a lid lower surface plate 10 that forms the lower surface of the lid 7, and a heat insulating material 11 is provided between the outer lid 8 and the lid lower surface plate 10. The lid 7 is rotatably supported by the main body 1 by a hinge 12 located on the right side of the drawing, and is constantly biased in the opening direction by a spring 13 provided on the hinge 12. On the other hand, on the left side of the main body 1 of the drawing, the lid 7 is engaged with and disengaged from the spring 13.
A clamp 14 that holds the clamp 14 in a closed state against the urging force is axially mounted. The lid bottom plate 10 is made of a material having thermal conductivity such as aluminum, and its surface is anodized to ensure corrosion resistance.

A rice-cooking heater 15 for heating the container 6 is provided above the reflection plate 5 below the container 6, and a cord-shaped heater as a container heating means is provided above the outer surface of the inner case 2. A body heater 16 is provided. Further, reference numeral 17 denotes a lid heater as a lid heating means for heating the lid lower surface plate 10, which is configured by covering a cord-shaped heater or the like with aluminum foil and adhesively fixing it to the upper portion of the lid lower surface plate 10. Then, with the lid 7 closed, the lid heater
The heat from 17 is radiated directly into the container 6 through the lid bottom plate 10.

Reference numeral 18 denotes a container sensor which is provided in the center of the lowermost part of the inner case 2 and serves as a container temperature detecting means for detecting the outer surface temperature of the container 6. The container sensor 18 has a thermistor 20 built in a vertically movable heat sensitive plate 19, and the heat sensitive plate 19 is constantly urged upward by a coil spring 21 so as to press the outer lower surface of the container 6 into pressure contact. . Also, 22
Is a lid sensor which is a lid temperature detecting means composed of a thermosensitive element such as a thermistor, which detects the temperature of the lid lower surface plate 10 in the vicinity of the lid heater 17. On the other hand, on the lower surface of the outer case 3, a cord reel 24 around which the power cord 23 is wound.
Is provided. Reference numeral 25 denotes a circuit board which is located between the inner case 2 and the outer case 3 and is provided on a side portion of the main body 1, and a control circuit unit 26 is mounted on the circuit board 25. Further, a unitized display operation panel 27 is provided on the upper side of the outer surface of the outer case 3.

FIG. 2 shows a front view of the display / operation panel 27 in the off state. In FIG. 2, a display section 31 provided on the left side of the display / operation panel 27 has a rice cooking lamp 32 for displaying the respective operation states and a heat retention. Lamp 33 and timer lamp 34
And a 12-hour current time display section including an AM / PM switching display section configured by an LCD
It has 35 and a cooking time display unit 36. Furthermore, as shown in FIG. 9, inside the cooking time display unit 36,
A long time hot water display unit 37 is provided which indicates that the cooked food in the container 6 has been hot for a long time. On the other hand, the operation unit 38 provided on the right side of the display / operation panel 27 is provided with a time setting switch 4 including a clock switch 39 and hour and minute switches.
0, rice cooker switch 41, heat retention switch 42, timer switch 43, and off switch 44. And
By using the time setting switch 40, the cooking time can be arbitrarily set in units of 5 minutes, and the timer can be set up to 23 hours 55 minutes after the current time by appropriately switching the display of am or pm. You can

FIG. 3 is a block diagram showing an electrical configuration, and 51 is a microcomputer constituting the control circuit unit 26, which is well known, and is a storage means 52 such as a ROM and peripheral means such as a clock means 53. Is equipped with. At the input side of the microcomputer 51, an input circuit 54,
The container sensor 18 and the lid sensor 22 are connected via 55. Further, the operation unit 38 including various switches provided in the display operation panel 27 is connected via another input circuit 56. On the other hand, on the output side of the microcomputer 51, the rice cooking heater 15,
The body heater 16 and the lid heater 17 are individually connected, and further, the display unit 31 provided in the display operation panel 27 is connected via the output circuit 60. Reference numeral 61 is a notification buzzer, which is connected to the microcomputer 51 via the output circuit 62.

Next, the configuration will be described with reference to FIG. 4, which is a circuit diagram of the power source section and the heater driving section. Reference numeral 71 is a power supply plug to which commercial AC power is supplied, and a power supply transformer 72 is connected between both ends of the power supply plug. Through this power supply transformer 72 and a constant voltage circuit 73, for example, a power supply voltage of DC 5V is supplied to the microcomputer 51. To be done. Also, the power plug
Between both ends of 71, the rice cooking heater 15 and the opening / closing contact 74 of the relay 74
A series circuit with A, a series circuit with the body heater 16 and the triac 75, and a series circuit with the lid heater 17 and the triac 76 are connected, respectively. And the coil of the relay 74
74B is a microcomputer via the relay drive circuit 77
When the coil 74B is energized, the open / close contact 74A is closed and the rice cooking heater 15 energizes and heats according to the output signal from the microcomputer 51. Also,
TRIAC 75 and 76 are TRIAC drive circuit 7 respectively
It is connected to the microcomputer 51 via 8, 79, and is configured to independently control the on / off of the body heater 16 or the lid heater 17 according to the output signal from the microcomputer 51. The power consumption of the rice cooking heater 15 is 1130.
The power consumption of W, the body heater 16 and the lid heater 17 is 50W. Further, the container sensor 18 and the lid sensor 22 are connected to the microcomputer 51, and the operation unit 38
The rice cooking switch 41, the timer switch 43, the off switch 44, and the like, which are included in FIG.

FIG. 5 shows the storage means during the heat retention process.
5 is a block diagram showing a processing procedure of a control program stored in 52. FIG. In the figure, reference numeral 81 is a heat retention control means for keeping the container 6 at a predetermined temperature during the heat retention process, and controls the body heater 16 to turn on or off based on the temperature detected by the container sensor 18. Reference numeral 82 denotes a lid heating control means for heating and controlling the lid heater 17 so that the temperature Tf detected by the lid sensor 22 is slightly higher than the temperature at which the container 6 is held while the body heater 16 is being energized by the temperature control means 81. is there. This heat retention control means 81
And the lid heating control means 82 constitutes a part of rice cooking control means (not shown) for executing a series of rice cooking operations,
The rice cooking control means has a remaining time calculating means for calculating the remaining time until the cooked time, and a long time when the buzzer 61 or the hot water display section 37 gives a notification when the remaining time before the cooked time is more than a predetermined value. It is equipped with a hot water notification means.

Next, in connection with the above construction, the control process from the start of rice cooking to the heat retention will be first described with reference to the relationship between the temperature changes of the container sensor 18 and the lid sensor 22 and the heating patterns of the heaters 15, 16 and 17. Description will be made based on the graph of FIG.

First, at the beginning of the rice cooking process, hot-boiled rice is cooked for 8 minutes. In this hot-pot cooking, control is performed in which only the rice-cooking heater 15 is energized for 3 minutes and then disconnected for 5 minutes. Then, the process shifts to a substantial rice cooking process, and in the initial stage of main rice cooking, the rice cooking heater 15 and the body heater 16 are continuously energized to heat the rice to be cooked in the container 6. Then, when the temperature Tn detected by the container sensor 18 reaches a temperature close to 100 ° C. and a predetermined time elapses, it is determined that the cooked food in the container 6 is in a boiling state, and the rice cooking heater 15 is passed through every 30 seconds. The power is cut off, and the amount of heating in the container 6 is reduced. Simultaneously with the detection of the boiling state, the lid heater 17 is controlled to switch on and off at a predetermined time interval, and the body heater 16 is continuously energized. After that, when the temperature Tn detected by the container sensor 18 reaches the cooking temperature which is set to about 120 ° C. in advance, it is determined that the inside of the container 6 has reached the dry-up state, and the process shifts from the main cooking process to the muffler process. . During this purging stroke, the rice cooking heater 15 is temporarily stopped and re-energized only for 30 seconds after the lapse of a predetermined time. Further, the body heater 16 is continuously energized after the main rice cooking until the end of the unevenness stroke. Further, the lid heater 17 is based on the detected temperature Tf of the lid sensor 22, and detects the detected temperature Tf.
If the temperature is less than 105 ° C, the power is turned on and the detected temperature Tf is 105.
If the temperature exceeds ℃
While maintaining the heating temperature of 10 at about 105 ° C., the generation of dew condensation water adhering to the lid bottom plate 10 is prevented.

When the purging process of 15 minutes is completed in this way, the heat retaining process is started. In this heat insulation process, rice heating heater
The body heater 16 is electrically disconnected and controlled via the heat retention control means 81 so that 15 is always in the power-off state and the temperature Tn detected by the container sensor 18 is maintained at 71 ° C. That is, the container sensor 18
When the detected temperature Tn is less than 71 ° C., the body heater 16 is energized, and when the detected temperature Tn is 71 ° C. or more, the body heater 16 is cut off. The lid heating control means 82 is a body heater.
The lid heater 22 keeps the temperature Tf detected by the lid sensor 22 0.5 ° C. higher than the heat retention temperature only when 16 is energized.
Turn on and off 17 For example, when the heat retention temperature in the heat retention control means 81 is set to Tn = 71 ° C., the detected temperature Tf of the lid sensor 22 is 7 when the body heater 16 is energized.
When the temperature is lower than 1.5 ° C, the lid heater 17 is energized, and when the detected temperature Tf is 71.5 ° C or higher, the lid heater 17 is turned off. On the other hand, when the body heater 16 is cut off, the lid heater
17 is also cut off. Therefore, the heating temperature of the lid lower surface plate 10 during the heat retention process repeats a change that is slightly higher or lower than the rice temperature due to the power interruption of the body heater 16. Then, when the heating temperature of the lid lower surface plate 10 becomes higher due to the energization of the body heater 16, water droplets that condense on the lid lower surface plate 10 evaporate. It can be avoided. Further, if the room temperature becomes low, the energization time of the body heater 16 during the heat retention process becomes long, so the lid heater 17
Also, the control time for turning on and off the power supply to the cover can be extended, and the occurrence of dew condensation due to the temperature decrease of the lid lower surface plate 10 can be prevented. On the other hand, when the room temperature is high, the energization time of the body heater 16 is shortened, so that the energization / interruption control time for the lid heater 17 is also shortened and the lid lower plate 10
It prevents the rice from drying due to excessive heating.

Next, FIG. 2 and FIGS. 7 to 9 are front views of the display unit in each step, and FIGS.
The process from the timer setting to the heat retention process will be described based on the flowcharts shown in FIG.

When the current time is set to 6:00 am and the cooked time is set to 8:00 pm in the off state where the rice cooking operation is not performed, as shown in FIG.
The present time display section 35 displays the characters "current time 6:00 am" and the cooking time display section 36 displays "characters cooking" 8:00 pm. At this time, when the timer switch 43 is pressed in step S1 of the flowchart shown in FIG. 10, the display form of the display unit 31 changes from FIG. 2 to FIG. 7, the timer lamp 34 lights up, and the process proceeds to step S2. After the transition, the timer operation starts. The remaining time calculating means calculates the remaining time from the current time to the cooked time, and when the current time is a predetermined time, for example, 12 hours or more before the cooked time, the process proceeds to step S3 shown in FIG. If the current time is within 12 hours of the cooking time, the process proceeds to step S10 of the flowchart shown in FIG.

In step S2, the timer switch is activated when the current time is a predetermined time or more before the cooking time.
If it is determined that 43 has been operated, the cooking time is 5
Five minutes before (step S4), the timer operation in step S3 is canceled and the process moves to the rice cooking process of step S5. Before the start of the rice cooking process, the rice is cooked after a timer operation for a predetermined time or more. Is notified by the buzzer 61. Also, as shown in FIG.
In the display section 31, the rice cooking lamp 32 is turned on instead of the timer lamp 34. Then, when the rice cooking process is completed in step S6, the process shifts to the mulling process of step S7, and when the predetermined cooking time is reached (step S6).
8) Then, the process proceeds to the heat retention step of step S9. During the heat retention process, as shown in FIG. 9, the heat retention lamp 33 is turned on in place of the rice cooking lamp 32, and the display of "long time hot water" by the long time hot water display unit 37 is displayed inside the cooked time display unit 36. Done.

On the other hand, when it is determined in step S2 that the time difference between the current time and the cooked time is within a predetermined time, as shown in the flowchart of FIG. 11, the cooked rice is cooked similarly to step S3 and step S4. 55 minutes before the time (step S11),
The timer operation in step S10 is canceled, and the process proceeds to the rice cooking process of step S12. At this time, the buzzer 61
Is not performed, a series of rice cooking operations are performed as it is, and when the rice cooking process is completed in step S13, the process shifts to the unevenness process of step S14, and when a predetermined cooking time is reached (step S15), step S16 is performed.
Move to the heat retention process. At this time, the display of "long-time hit" by the long-time hit display unit 37 is not performed.

In step S9, the predetermined time as the reference for the "long-time hit" display is set at room temperature or in the container 6
It may be variable depending on the conditions such as the water temperature inside. For example,
As shown in the flow chart of FIG. 12, at the start of timer rice cooking by pressing the timer switch 43 (step S21), the remaining time calculating means determines whether the room temperature is 10 ° C. or lower based on the temperature detected by the lid sensor 22. When the determination is made (step S22) and the room temperature is a low temperature of 10 ° C. or lower, the predetermined time in step S2 is set to 16 hours (step S23). If the room temperature is 10 ° C. or higher, the process proceeds to step S24, and it is determined whether the room temperature exceeds 25 ° C.
When the temperature is higher than 5 ° C, the predetermined time is set to 12 hours (step S25), and when the room temperature does not exceed 25 ° C, the predetermined time is set to 14 hours (step S26). It is possible to change the display standard of "Hitashi for a long time" depending on the room temperature.

As shown in the flow chart of FIG. 13, at the time of starting rice cooking in step S31, the remaining time calculating means determines whether the water temperature in the container 6 is 10 ° C. or lower based on the temperature detected by the container sensor 18. (Step S3
2) If the water temperature is a low temperature of 10 ° C. or lower, the predetermined time is set to 16 hours (step S33). At this time, if the water temperature is 10 ° C or higher, step S
34, it is determined whether or not the water temperature exceeds 25 ° C. If the water temperature is a high temperature exceeding 25 ° C, the predetermined time is set to 12 hours (step S35), and the water temperature is 25 ° C. If the time does not exceed the limit, the predetermined time is set to 14 hours (step S36), so that "long-time hit"
It becomes possible to change the display standard of according to the water temperature.

As described above, according to the present embodiment, only while the body heater 16 is energized by the heat retention control means 81 so that the heating temperature of the lid lower surface plate 10 does not always become higher than the rice temperature.
Since the temperature of the lid heater 17 is controlled by the lid heating control means 82 so that the temperature of the lid lower surface plate 10 is higher than the temperature of the container 6, the lid lower surface plate is not provided as in the present embodiment. Ten
As a result, even with a rice cooker of a type that directly heats rice, it is possible to suppress drying of the upper surface of the rice for a long time. In addition, since the lid heater 17 is controlled to switch on and off based on the heat retention temperature of the container 6 only when the body heater 16 is energized, the amount of heat required for heat retention in response to variations in room temperature and variations in heat retention amount. The lid lower surface plate 10 is heated in conjunction with the above, and excessive heating or weakening of the lid lower surface plate 10 is suppressed. Therefore, the temperature difference between the lid bottom plate 10 and the rice can be maintained in a predetermined state in any situation without being affected by room temperature fluctuations, fluctuations in the amount of heat retention, and the like. It is possible to eliminate problems such as dryness and yellowing of rice. Moreover, since the heating temperature of the lid lower surface plate 10 is certainly higher than the rice temperature while the body heater 16 is energized, the water droplets condensed on the lid lower surface plate 10 evaporate and the condensed water drops on the upper surface of the rice. Can be prevented. Further, when the lid 7 is opened, the lid lower surface 10
However, since the lid heater 17 is not always controlled to switch on and off, it is possible to prevent the disadvantage that the lower surface 10 of the lid is unnecessarily heated.

Further, as an effect of the embodiment, when water and rice are kept soaked by setting a timer for a long time, lactic acid bacteria, oleic acid, linoleic acid, etc. contained in rice are Fatty acid elutes and the pH of water changes to an acidic direction to cause a bad odor. In the rice cooker of this example, when the time difference between the current time and the cooked time is at least 12 hours or more, at the start of rice cooking. The buzzer 61 informs you, and the hot water display section 37 displays "Hot water for a long time" when the temperature is kept warm. It is possible for the user to understand and be convinced in advance that it is due to what has been done. In addition, in the conventional rice cooker, in order to suppress the generation of odor due to hot water for a long time,
When setting the cooked time exceeding a predetermined time, there was a case where this cooked time was forcibly set to a predetermined maximum time, for example, about 13 hours, but the rice cooker of the present embodiment has a maximum of 23 hours. It is possible to set the cooked time up to 55 minutes, so that the cooked time is too early to cause excessive spotting, or the warming time after the cooked time is long before eating, which significantly deteriorates the taste. You can eliminate the disadvantages. Furthermore, in low water temperatures such as in winter, even if the cooking time is set slightly longer, there is almost no effect after cooking, but the conventional rice cooker forcibly limits the maximum cooking time. Therefore, even if the cooked time display unit 36 displays 24 hours, its characteristics cannot be utilized. On the other hand, in the rice cooker of the present embodiment, when the water temperature and room temperature are low, in consideration of the fact that the odor does not occur even in a long-time soak, the buzzer 61 informs and the "long-time soak" display is performed. It is possible to perform detailed control according to the water temperature in the container 6 and the external room temperature by setting a long reference time and conversely setting a short predetermined time when the water temperature and room temperature are high. It is easy to use, and you can set the cooking time up to 23 hours 55 minutes, so you can switch between morning and afternoon and 12
It is possible to effectively use the function of the cooked time display unit 36 in combination with the time display.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the gist of the present invention. For example, the degree of drying of the upper surface of the rice and dew condensation on the lower surface of the lid can be arbitrarily adjusted by appropriately setting and changing the temperature difference between the heating temperature of the lower surface of the lid and the heat retention temperature in the lid heating control means. Further, as the lid sensor, a thermal fuse or a thermostat having a safety function may be used in addition to the heat sensitive element such as the thermistor.

[0027]

According to the present invention, the container, the container heating means for heating the container, the container temperature detecting means for detecting the temperature of the container, and the container heating means based on the temperature detected by the container temperature detecting means. The temperature control means for keeping the container at a predetermined temperature by shutting off electricity, a lid for covering the upper opening of the container, a lid heating means for heating the lower surface of the lid, and a temperature for the lower surface of the lid. A lid temperature detecting means for detecting, and a lid for heating and controlling the lid heating means such that the temperature detected by the lid temperature detecting means becomes higher than the heat retaining temperature of the container during energization of the container heating means by the heat retaining control means. It is provided with a heating control means, and in any situation, it is possible to provide a rice cooker capable of preventing the upper surface of rice from being dried and dripping dew during heat retention.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a rice cooker showing an embodiment of the present invention.

FIG. 2 is a front view of the same display operation panel.

FIG. 3 is a block diagram showing an electrical configuration of the same.

FIG. 4 is a circuit diagram of a power supply section and a heater driving section of the same as above.

FIG. 5 is a block diagram of the same heat retention step.

FIG. 6 is a circuit diagram of a power supply unit and a heater drive unit of the above.

FIG. 7 is a front view of the display section when the same timer switch is operated.

FIG. 8 is a front view of the display unit during the rice cooking process of the above.

FIG. 9 is a front view of the display unit during the same heat retention process.

FIG. 10 is a flowchart showing a series of control processes of the above.

FIG. 11 is a flowchart showing a series of control processes of the above.

FIG. 12 is a flowchart showing a procedure for setting a predetermined time in the same as above.

FIG. 13 is a flowchart showing a procedure for setting a predetermined time in the same as above.

[Explanation of symbols]

 6 Container 7 Lid 10 Lower Lid Plate (Lower Lid) 16 Body Heater (Container Heating Means) 17 Lid Heater (Lid Heating Means) 18 Container Sensor (Container Temperature Detection Means) 22 Lid Sensor (Lid Temperature Detection Means) 81 Heat Insulation Control means 82 Lid heating control means

Claims (1)

[Claims] 1. A container, a container heating means for heating the container, and a container temperature detecting means for detecting the temperature of the container,
Based on the temperature detected by the container temperature detecting means, the container heating means is electrically disconnected to keep the container warm at a predetermined temperature, a temperature control means for covering the upper opening of the container, and a lower surface of the cover. A lid heating means for heating the lid, a lid temperature detecting means for detecting the temperature of the lower surface of the lid, and a temperature detected by the lid temperature detecting means while the container heating means is being energized by the heat retention control means And a lid heating control means for controlling heating of the lid heating means so as to be higher than the above.