JP2000220836A - Heating cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To retain the temperature of a matter to be heated in accordance with the kind, amount or the taste of a user, in a heating cooker equipped with a temperature retaining function. SOLUTION: When temperature retaining operation is effected, a user operates a 'hot storage chamber' key 14 (S1) and, thereafter, selects the course of retaining temperature (standard, strong or weak) (S4). The temperature retaining operation is prohibited when the initial temperature of a heating cooking chamber, which is detected by a temperature sensor, is higher than 150 deg.C. (S2, S3). The set temperature in the chamber under the standard course is specified so as to be 120 deg.C, and the same under the 'weak' course is specified so as to be 90 deg.C while the same under the 'strong' course is specified so as to be 130 deg.C and, further, the temperature retaining period of time is set so as to be 30 min in every cases (S5-S13). Under the temperature retaining operation, the ON, OFF of upper and lower heaters are controlled based on an inside temperature of the chamber (S14) while the alternate (10 see/20 sec) excitation and interception of the upper and lower heaters are repeated with the frequency of 30 see during the putting ON of the heaters. When 30 min has elapsed from the beginning of the temperature retaining operation, the temperature retaining operation is finished automatically (S15).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating cooker having a function of keeping a heated object such as food or a container (tableware) cooked in a cooking chamber.

[0002]

Conventionally, there has been provided an insulated storage (heat storage) in which cooked food is accommodated in a heating space and heated by a heater to maintain the temperature. In this method, only the heater is continuously energized, and it does not control the temperature in the refrigerator and thus the temperature of the food. Therefore, it is conceivable to control the temperature in the refrigerator by detecting the temperature in the refrigerator with a temperature sensor and controlling the heater to be turned on and off based on the detected temperature. However, simply controlling the inside of the refrigerator to a fixed temperature (for example, 120 ° C.) is still insufficient from the viewpoint of keeping warm according to the type and amount of the object to be heated and keeping warm according to the user's preference. It is something.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a device having a heat retaining function, which is capable of retaining heat in accordance with the type and amount of an object to be heated or the taste of a user. To provide a heating cooker that can be used.

[0004]

According to a first aspect of the present invention, there is provided a heating cooker, in which a heating object is disposed, a heater heating means for heating the object in the heating chamber, and A heat insulation operation control means for controlling the heater heating means to keep the object to be heated at a predetermined heat insulation temperature, wherein the heat insulation operation control means can execute the heat insulation operation at a plurality of different heat insulation temperatures. It is characterized in that it is configured as:

[0005] According to this, by the heat retention operation control means,
The heating operation is performed in which the heater heating means is controlled to keep the object to be heated placed in the cooking chamber at a predetermined temperature. At this time, a plurality of temperatures for the object to be heated are provided. Therefore, according to the type and amount of the object to be heated or the preference of the user, it is possible to select a suitable heat retaining temperature from the plurality of heat retaining temperatures and execute the heat retaining operation. In addition, the thing to be heated here includes a food and a container (tableware such as a dish), and the warming operation includes performing warming (warming) of only the dishes.

In this case, an internal temperature detecting means for detecting the temperature of the cooking chamber is provided, and the heat keeping operation control means is configured to control the heater heating means based on the detection of the internal temperature detecting means. (Invention of claim 2) Alternatively, food temperature detecting means for detecting the temperature of the object to be heated is provided, and the warming operation control means is configured to control the heater heating means based on the detection of the food temperature detecting means. (Claim 3
Invention). According to these, since the control of the heater heating means is performed based on the temperature in the refrigerator or the temperature of the object to be heated, the temperature in the refrigerator or the object to be heated can be maintained at a target constant heat-retaining temperature, and the temperature can be stabilized. It is possible to keep warm.

[0007] Here, although there is a difference depending on the type of food, the cooking method, and the like, if the operation of keeping the food warm is continued for a long time, the water evaporates (dry) from the food and becomes hard, or conversely, the surrounding steam is removed. There is a possibility that the quality (taste) of the food is reduced, for example, the food is absorbed and becomes soft. Therefore, it is desirable to set an upper limit for the duration of the warming operation (the invention of claim 4), whereby it is possible to prevent the deterioration of the food quality due to continuing the warming operation for a long time.

Further, according to the study of the present inventors, more specifically, some foods may cause a deterioration in quality if the time of the warming operation exceeds 30 minutes, and therefore, the duration of the warming operation may be reduced. If it is configured to be able to be set within 30 minutes (the invention of claim 5), it is possible to reliably prevent deterioration in the quality of food. In addition, at this time, if the temperature in the refrigerator exceeds 150 ° C. during the warming operation, the food may be overheated and dry. Therefore, the heat retention operation control means sets the upper limit of the temperature of the cooking chamber to 150 ° C.
If the configuration is such that the heat retention operation is controlled (the invention of claim 6), it is possible to prevent such overheating of the object to be heated.

When the food is large (large in quantity), if the heat retention temperature by heating the heater is relatively low, heat does not sufficiently reach the inside of the food, and the temperature inside the food becomes lower than the optimum temperature. There is a risk of falling. Therefore, if weight detecting means for detecting the weight of the object to be heated is provided, and the heat retaining operation control means is configured to automatically set the heat retaining temperature in accordance with the weight detected by the weight detecting means (claim 7) ), It is possible to keep the temperature at an appropriate temperature according to the amount of the object to be heated, and it is possible to prevent a decrease in the internal temperature when the amount of the object to be heated is large and an overheating when the amount of the object to be heated is small .

As the heater heating means, a heater for heating an object to be heated by radiant heat, a heater for heating an object to be heated by hot air, and the like can be employed. Therefore, it is preferable to employ a heater for heating an object to be heated by radiant heat as the heater heating means used for the heat retention operation (the invention of claim 8).

Further, the heater heating means can be constituted by a plurality of heaters provided at different positions. At this time, the heat insulation operation control means controls the heat insulation operation by alternately turning off and on the plurality of heaters. (Invention of claim 9). According to this, the object to be heated can be uniformly heated from different directions, and temperature unevenness of the object to be heated can be prevented.

At this time, in the case where the power supply / disconnection control of a plurality of heaters is performed alternately, it is desirable for control to repeat the power supply / disconnection periodically. However, if the cycle is long, fluctuations in the internal temperature (temperature ripple) may occur. ) Is relatively large, and a shorter cycle is more suitable for the heat-retaining operation. According to the study of the present inventor, if the power cutoff control of a plurality of heaters is repeated in a short cycle of 30 seconds or less (the invention of claim 10), the fluctuation of the internal temperature (temperature ripple) is small, It became clear that control more suitable for heat retention can be performed.

A heater positioned on the front side of the food;
In the case of performing a warming operation using a heater located on the opposite side, that is, on the side of the container supporting the food, generally, the container has a larger heat capacity, and if the food is strongly heated from the surface side of the food, the food is excessively heated. Heating (drying or burning) may occur.
Therefore, the energization time of the heater located on the front side of the food is
It is desirable that the energization time of the heater located on the container side be shorter than the energizing time (the invention of claim 11), whereby the temperature on the food surface side and the container side can be made uniform, and the food surface side Overheating can be suppressed. At this time,
The higher the heat retention temperature, the shorter the energization time of the heater located on the front side of the food may be shortened (the invention of claim 12), thereby effectively suppressing overheating on the front side of the food. it can.

Further, it is possible to rotate the rotating plate on which the object to be heated is placed during the warming operation (the invention of claim 13). According to this, since the heating can be performed while changing the position or the direction of the object to be heated with respect to the heater heating means every moment, uniform heating can be achieved, and the temperature unevenness of the object to be heated can be suppressed. Can be.

In each of the above-mentioned heating cookers, it is possible to display a message that the temperature of the container supporting the food is high when the heat-retaining operation is executed (the invention of claim 14). According to this, it is possible to notify the user that the temperature of the container supporting the food is high,
The user can be alerted when taking out the container.

[0016] The heat keeping operation control means may be configured such that when the initial temperature in the heating cooking chamber is higher than a predetermined temperature, the power supply to the heater heating means is not executed (the invention of claim 15). According to this, it is possible to prevent wasteful heating of the heater in a state where the initial temperature in the heating chamber is sufficiently high, for example, due to residual heat of the previous cooking, etc.
It is possible to prevent overheating of the object to be heated such as drying of food.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments in which the present invention is applied to a microwave oven having an oven (heater) function will be described below with reference to the drawings. (1) First Embodiment First, a first embodiment (corresponding to claims 1, 2, 4, 8, 9, 10, 11, 15) of the present invention will be described with reference to FIGS. State.

FIG. 2 schematically shows a configuration of a microwave oven as a heating cooker according to the present embodiment. Here, a rectangular box-shaped cooking chamber 1 whose front opening is opened and closed by a door (not shown) is provided in the main body of the microwave oven. A mounting plate 2 on which an object to be heated (food or a container (tableware)) is mounted is provided at a bottom portion in the cooking chamber 1. Although not shown, a magnetron or the like for supplying microwaves to the cooking chamber 1 to perform range cooking is provided in the main body.

An upper heater 3 made of, for example, a lamp heater is provided on a ceiling portion of the cooking chamber 1, and a lower heater made of, for example, a flat heater is provided on a bottom portion of the cooking chamber 1 which is located at a position different from the upper heater. 4 are provided. The upper heater 3 and the lower heater 4 heat an object to be heated by radiant heat, and the plurality (two) of the upper heaters 3 and the lower heaters 4 are heater heating means for heating the object to be heated. Is configured.

In this case, the upper heater 3 is located on the surface side of the food, and the lower heater 4 is located on the container side supporting the food. The upper heater 3 and the lower heater 4 are connected to an AC power supply 7 via relays 5 and 6, respectively. Further, a temperature sensor 8 composed of, for example, a thermistor is provided on the left side wall of the cooking chamber 1 as a temperature detecting means for detecting the temperature inside the cooking chamber 1.

On the other hand, an operation panel 9 as shown in FIG. 3 is provided on the front surface of the main body. The operation panel 9 is provided with a display unit 10 for displaying necessary information such as a cooking time and a cooking mode, and an operation unit 11 having a plurality of operation keys. Although a detailed description is omitted, the operation unit 11 includes a start key 12 for instructing start of cooking, a dial 13 for time setting,
A “warm storage” key 14 for selecting a warming operation, a finishing adjustment key 15 in which the strength and weakness are paired, a cancel key 16 and the like are included.

Then, as shown in FIG.
A control circuit 17 mainly composed of a microcomputer is provided. The control circuit 17 receives a key operation signal from the operation unit 11 and a signal for detecting the inside temperature of the refrigerator from the temperature sensor 8. The control circuit 17 controls the display on the display unit 10 based on the various input signals according to a control program stored in advance, and also controls the cutoff of the upper and lower heaters 3 and 4 via the relays 5 and 6. Power control. The magnetron is also controlled by the control circuit 17. Thus, when the user operates the operation unit 11 to select a desired cooking mode, menu, time, and the like, and turns on the start key 12, the control circuit 17 performs heating cooking.

As will be described in detail in the following description of the operation,
The control circuit 17 controls the upper heater 3 and the lower heater 4 based on a user's predetermined key operation (operation of the “hot storage” key 14) by the software configuration,
A warming operation is performed in which the objects to be heated (cooked foods, dishes, etc.) arranged in the heating chamber 1 are kept at a predetermined temperature. Therefore, the control circuit 17 functions as a warming operation control unit.

When performing this warming operation, the control circuit 1
7 is based on the internal temperature detected by the temperature sensor 8 so that the internal temperature in the cooking chamber 1 is maintained at a predetermined set temperature (slightly higher than the heat retaining temperature).
The lower heaters 3 and 4 are turned on and off. More specifically, the upper and lower heaters 3 and 4 are continuously turned on until the temperature reaches the set temperature at the beginning of the warming operation, and thereafter,
Control is performed such as turning off when the temperature exceeds the set temperature, and turning on when the temperature drops by, for example, 5 degrees below the set temperature. At this time, in this embodiment, a plurality of courses (standard, strong, weak) of three different heat retaining temperatures are provided in this case, and the user can select the course.

That is, if the user operates the "warm storage" key 14 to start the warming operation as it is, the "standard" course is automatically selected, and the "standard" course is automatically selected. The set temperature is, for example, 120 ° C. On the other hand, if the user operates either the “strong” or “weak” finish adjustment key 15 following the operation of the “hot storage” key 14, the “strong” course or the “weak” course You can choose. The set temperature is, for example, 130 ° C. higher than that of “standard” in the case of the “strong” course, and 9 lower than that of “standard” in the case of the “weak” course, for example.
It is set to 0 ° C.

In the present embodiment, when the upper and lower heaters 3 and 4 are turned on during the warming operation, the upper and lower heaters 3 and 4 are energized alternately at a predetermined cycle, instead of energizing them simultaneously. The thing is to be repeated. Specifically, as shown in FIG. 4, in a short cycle of 30 seconds, the energizing time of the upper heater 3 located on the surface side of the food is 10 seconds, and the energizing time of the lower heater 4 located on the container side is 20 seconds. The energization time of the upper heater 3 is shorter than the energization time of the lower heater 4.

In the present embodiment, an upper limit is set for the duration of the warming operation, and in this case, the upper limit is set to 30 minutes. Further, in the present embodiment, the control circuit 1
7 determines whether the initial temperature of the cooking chamber 1 detected by the temperature sensor 8 is higher than a predetermined temperature (in this case, 150 ° C.) when starting the warming operation, and executes the heater heating when the initial temperature is higher than the predetermined temperature. In other words, the upper and lower heaters 3 and 4 are not energized.

Next, the operation of the above configuration will be described with reference to FIGS. The flowchart of FIG.
3 shows an outline of a control procedure executed by a control circuit 17 in a warming operation. Here, when the user wants to keep the cooked food warm, as described above, the door of the cooking chamber 1 is opened and closed, and the food is placed on the placing plate 2, and the operation panel is operated. Turn on the “Hot storage” key 14 of No. 9 and
After selecting the course (the heat retention temperature is one of “standard”, “strong”, and “weak”), the heat retention operation is started. As a result, the control circuit 17 executes the heat retention operation as shown in the flowchart of FIG.

That is, when the power of the cooking device is turned on (it is automatically turned on by opening and closing the door), the user first turns on the "warm storage" key 14 (step S).
1). Then, in step S2, the initial temperature in the cooking chamber 1 detected by the temperature sensor 8 is set to the predetermined temperature (15
0 ° C.) or less, and if the initial temperature is higher than 150 ° C. (No in step S2), the display unit 1
An error message is displayed at 0, and the operation of turning on the "warm storage" key 14 is canceled (step S3). This allows
For example, in a state where the initial temperature in the heating cooking chamber 1 exceeds 150 ° C. due to the residual heat of the previous cooking or the like, the heat keeping operation is prohibited, thereby preventing overheating of the object to be heated such as drying of food. be able to.

When the initial temperature is 150 ° C. or lower (Yes in step S2), selection of a course (heat retention temperature) is accepted (step S4). In this case, as described above, if the user operates either “strong” or “weak” of the finishing adjustment key 15, “strong” or “weak” is selected (steps S6 and S7), and the finishing is performed. If there is no operation of the adjustment key 15, "standard" is selected (step S5).

Here, as shown in FIG. 4, when the "standard" course is selected (Yes in step S5), the set temperature in the refrigerator is set to 120 ° C. (step S8) and the maximum temperature is set. The warming time is set to 30 minutes (step S
9). When the “weak” course is selected (Yes in step S6), the set temperature in the refrigerator is set to 90 ° C. (step S10), and the maximum heat retention time is set to 30 minutes (step S11). ). When the "strong" course is selected (Yes in step S7), the set temperature in the refrigerator is set to 130 ° C (step S12), and the maximum heat retention time is set to 30 minutes (step S13).

Then, a warming operation is performed (step S14). In the warming operation, as described above, based on the inside temperature detected by the temperature sensor 8 and the set temperature, the upper and lower heaters 3 are continuously operated until the inside temperature reaches the set temperature at the beginning of the warming operation. , 4 are turned on, and then turned off when the internal temperature exceeds the set temperature, and turned on when the internal temperature falls, for example, 5 degrees below the set temperature. As a result, the temperature in the refrigerator is maintained near the set temperature, and the food in the cooking chamber 1 is kept at the heat retention temperature corresponding to the set temperature.

FIG. 5 shows the internal temperature (black triangle) with time when the "standard" course was selected and the pilaf (for two persons) was kept warm by an experiment conducted by the present inventor.
And changes in food temperature (white rhombus). The initial temperature in the refrigerator is about 40 ° C., from which the temperature rises to the set temperature (120 ° C.) in about 10 minutes, and thereafter, the temperature is almost maintained at the set temperature while slightly rising and falling. And
The food temperature (the temperature at the center of the food) is maintained (maintained) at approximately 70 ° C.

Thus, when the "standard" course is selected, the internal temperature is maintained at approximately 120 ° C., and when the "weak" course is selected, the internal temperature is approximately 90 ° C.
° C and when the “stronger” course is selected,
The temperature in the refrigerator is maintained at approximately 130 ° C. Therefore, the user can select a desired course (heat-retaining temperature) and execute the heat-retaining operation according to the type and amount of the object to be heated (food) or his / her preference.

At this time, when the upper and lower heaters 3 and 4 are turned on, the upper and lower heaters 3 and 4 are energized alternately, for example, every 30 seconds at a time ratio of 10 seconds / 20 seconds. Is to be repeated. With this, the radiant heat of the upper and lower heaters 3 and 4 achieves uniform heating from both the upper and lower sides of the food. However, when heating is performed from the food surface side and the container side, the heat capacity of the container is higher. Big,
If the food is strongly heated from the surface side, the food may be overheated (dried or burned). However, here, by making the energization time of the upper heater 3 shorter than the energization time of the lower heater 4, it is possible to equalize the temperature between the food surface side and the container side, and to achieve the food surface side Overheating can be suppressed.

Furthermore, since the cycle of the power cutoff control of the upper and lower heaters 3 and 4 is shortened to 30 seconds, fluctuations in the internal temperature (temperature ripple) are small, and control more suitable for keeping the temperature can be performed. It became clear. FIG. 6 shows the results of experiments performed by the inventor when the set temperature was set to 120 ° C.
When the cycle of the power cutoff control of the upper and lower heaters 3 and 4 is 30 seconds (black diamond), the cycle is 60 seconds (upper and lower heaters 3 and 4).
, Are alternately set to 20 seconds / 40 seconds (interruption control) at a time ratio of 20 seconds / 40 seconds (open squares). When the cycle is set to 60 seconds, the fluctuation of the internal temperature (temperature ripple) becomes large. However, by setting the cycle as short as 30 seconds or less, the fluctuation of the internal temperature is small and stable temperature control can be performed. Became clear.

The above-described warming operation can be forcibly terminated by, for example, the user turning on the cancel key 16 of the operation panel 9. In this case, any of the courses can be performed. Even when the set maximum heat retention time (30 minutes) elapses, the process automatically ends (Yes in step S15). here,
The maximum heat retention time (upper limit of the duration of the heat retention operation) is 30
The reason for the minute is as follows.

That is, although there are differences depending on the type of food and the cooking method, if the heat-retention operation of the food is continued for a long time, the water evaporates (dry) from the food and becomes hard, or conversely, the surrounding vapor is removed from the food. There is a possibility that the quality (taste) of the food may be deteriorated, for example, when the food is absorbed and becomes soft.
FIG. 7 shows the results of a sensory test for examining the change in taste due to the heat retention time when five kinds of foods were kept at three kinds of keeping temperatures. Although there is a slight difference depending on the food type, in all samples, the results show that if the heat retention time is 30 minutes, the quality is almost the same as that immediately after cooking (there is no significant difference). Therefore, by setting the duration of the warming operation to 30 minutes or less, it is possible to reliably prevent the quality of the food from deteriorating.

As described above, according to the present embodiment, a plurality of heat retaining functions are provided, and a plurality of heat retaining temperatures can be provided, and the heat retaining operation can be performed based on a user's selecting operation. It has an excellent effect that it is possible to keep the temperature at the keeping temperature according to the kind and the amount or the taste of the user. In addition, since the heat keeping operation is performed based on the temperature inside the refrigerator, the inside of the refrigerator can be maintained at a target constant heat retaining temperature, and stable heat retention can be performed. In particular, in the present embodiment, the upper limit of the duration of the warming operation is set to 3
Since the time is set to 0 minutes, it is possible to prevent the deterioration of the quality of food due to continuing the heat keeping operation for a long time.

Furthermore, in this embodiment, in particular, the warming operation is executed while the upper and lower heaters 3 and 4 are alternately turned off and on.
The cycle at that time was shortened to 30 seconds, and the energizing time of the upper heater 3 located on the surface side of the food was shorter than the energizing time of the lower heater 4, so that the temperature unevenness of the food and the fluctuation of the temperature in the refrigerator were reduced. It is possible to reduce the size, and to perform control more suitable for keeping heat. Further, when the initial temperature in the cooking chamber 1 is higher than 150 ° C., the heat retention operation is not performed, so that wasteful heating of the heater is prevented, and the heating of the object to be heated such as drying of the food is prevented. An advantage that overheating can be prevented can also be obtained.

(2) Second Embodiment Next, a second embodiment (corresponding to claim 7) of the present invention will be described with reference to FIGS. In the second to sixth embodiments described below, the basic hardware configuration of the heating cooker is the same as that of the first embodiment, and thus is the same as that of the first embodiment. For the parts, new illustrations and detailed explanations are omitted, and reference numerals are used in common, and only different points will be described below.

As shown in FIG. 9, the second embodiment is provided with a weight sensor 21 as a weight detecting means for detecting the weight of an object to be heated. This weight sensor 21
Is connected to the lower end of the shaft 22 of the
The weight acting on the (shaft 22) is detected. The output signal from the weight sensor 21 is input to the control circuit 17 via the weight detection circuit 23.

Instead of the user selecting the heat retaining temperature (set temperature) by key operation in the first embodiment, the control circuit 17 as the heat retaining operation control means has a software configuration by means of its software. When driving,
The heat retention temperature (in this case, the set temperature in the refrigerator) is automatically set according to the weight detected by the weight sensor 21.

That is, as shown in the flowchart of FIG. 8, when the "warm storage" key 14 is turned on (step S1), the weight W of the object to be heated on the placing plate 2 is detected by the weight sensor 21. It is detected (step S21). Then, in the next steps S22 and S23, the weight W of the object to be heated is
It is determined which of the three stages of 250 g or less, 251 g or more and 400 g or less, or 401 g or more.

When the weight W of the object to be heated is a small amount of 250 g or less (Yes in step S22), the set temperature in the refrigerator is set to 90 ° C. (step S24), and the maximum warming time is 30 minutes. Minutes (step S2
5). The weight W of the object to be heated is 251 g or more and 400 g.
In the case of the following intermediate amount (Yes in Step S23), the set temperature in the refrigerator is set to 120 ° C. (Step S26), and the maximum heat retention time is set to 30 minutes (Step S27). ).

Further, when the weight W of the object to be heated is a large amount of 401 g or more (No in step S23), the set temperature in the refrigerator is set to 130 ° C. (step S2).
Along with 8), the maximum heat retention time is set to 30 minutes (step S29). Then, similarly to the first embodiment, the warming operation is executed (step S14), and when the set maximum warming time (30 minutes) elapses, the warming operation automatically ends (step S15). Ye
s).

Here, when the food is large (large amount), if the heat retention temperature by the heater heating is relatively low,
There is a situation in which heat is not sufficiently distributed to the inside of the food, and the temperature inside the food falls below an appropriate temperature. However, in the present embodiment, the set temperature is automatically set so that the larger the weight W in accordance with the weight W of the object to be heated, the higher the internal temperature is set, so that the temperature is kept at an appropriate temperature according to the amount of the object to be heated. Can be performed, and when the amount of the object to be heated is large,
It is possible to prevent overheating when the amount is small.

(3) Third Embodiment FIG. 10 shows a third embodiment of the present invention (corresponding to claim 12).
Is shown. This embodiment is different from the above-described first embodiment in that, depending on the heat retaining temperature (set temperature in the refrigerator),
The point is that the energization time ratio in the alternating energization of the lower heaters 3 and 4 is changed.

That is, when the upper and lower heaters 3 and 4 are turned on, the upper heater 3 and the lower heater 4 are energized alternately at a predetermined energizing time ratio in a cycle of 30 seconds. When the set temperatures are 90 ° C. and 120 ° C., the upper heater 3 is energized for 9 seconds, the lower heater is energized for 18 seconds, and both are repeatedly turned off for 3 seconds.
At 0 ° C., the upper heater 3 is energized for 5 seconds, and the lower heater is set to 1
The power supply is repeated for 8 seconds, and both are repeatedly cut off for 7 seconds.

According to this, the higher the heat retention temperature (set temperature), the shorter the on-time of the upper heater 3 located on the front side of the food, so that the upper temperature is higher than when the set temperature is lower.
Even if the on time of the lower heaters 3 and 4 is long, overheating of the food surface side can be effectively suppressed. still,
When the heat retaining temperature is high, the energizing time of the lower heater 4 may be increased in addition to shortening the energizing time of the upper heater 3. The energization time ratio may be changed depending on whether the set temperature is 90 ° C. or 120 ° C.

(4) Fourth Embodiment FIG. 11 shows a fourth embodiment of the present invention (corresponding to claim 13).
Is shown. This embodiment is different from the above-described first embodiment in that a rotating dish 24 on which an object to be heated is placed is provided at the inner bottom of the cooking chamber 1, and the heating cooking chamber 1 is placed outside the cooking chamber 1 during the heat-retention operation. The rotary dish 24 is rotated via a rotary shaft 26 by an RT motor 25 provided at the bottom. According to this, since the object to be heated is rotated, the heating and the position of the object to be heated with respect to the upper and lower heaters 3 and 4 can be changed every moment, so that the heating can be performed uniformly. And the temperature unevenness of the object to be heated can be further suppressed.

(5) Fifth Embodiment FIGS. 12 and 13 show a fifth embodiment of the present invention.
4). In this embodiment, when the warm-up operation is performed, the display unit 10 displays that the temperature of the container (tableware such as a dish) supporting the food is high (high temperature warning display). It is.

That is, as shown in the flowchart of FIG. 12, when the warming operation is started (step S14), in step S31, a certain period of time (in this case, the inside of the refrigerator rises to almost the set temperature) from the start of the warming operation. Is determined, and if 10 minutes have elapsed since the start of the warming operation (Yes), a high-temperature warning display is displayed on the display unit 10 in the next step S32. FIG. 13 shows an example of this high-temperature caution display.
The characters "dish" and "hot" are turned on (or flashed). Although not shown in FIG. 12, the high-temperature caution display is continuously performed until the door of the heating cooking chamber 1 is opened / closed (opened).

Thus, it is possible to notify the user that the temperature of the container supporting the food is high and to alert the user to take out the container. In addition, instead of performing the display 10 minutes after the start of the warming operation, the display may be performed earlier, such as immediately after the start of the warming operation, or may be performed later (for example, after 29 minutes).
It goes without saying that the display may be performed at the same time.

(6) Sixth Embodiment FIG. 14 shows a sixth embodiment (corresponding to claim 1) of the present invention. In this embodiment, the control circuit 17 controls the upper and lower heaters 3 and 3 based on the internal temperature detected by the temperature sensor 8.
4, the upper and lower heaters 3 and 4 are controlled to be turned on and off at on and off time periods fixedly set in advance in accordance with the course of the drying operation (heating temperature). .

That is, when the "standard" course is selected (Yes in step S5), the ON time of the upper and lower heaters 3, 4 is set to 15 seconds out of 30 seconds (step S5).
41). When the "weak" course is selected (Yes in step S6), the ON time of the upper and lower heaters 3, 4 is set to 10 seconds out of 30 seconds (step S4).
2) Further, when the "stronger" course is selected (Yes in step S7), the ON time of the upper and lower heaters 3, 4 is set to 20 seconds out of 30 seconds (step S4).
3). Note that these ON times can be obtained by experimentally obtaining appropriate values in advance so that the internal temperature becomes the target temperature.

Therefore, when the warming operation is performed (step S1)
In 4), on / off control of the upper and lower heaters 3 and 4 is performed in the on / off time period set in steps S41 to S43, and the temperature in the refrigerator is maintained at a temperature corresponding to the course. Appropriate warming of the heated material is performed. According to this, the temperature sensor 8 becomes unnecessary, and the control can be simplified.

(7) Other Embodiments Although not shown, the present invention is not limited to the above-described embodiments, and various modifications as described below are possible. The present invention can be appropriately changed and implemented without departing from the gist.

That is, in the above embodiment, "standard", "weaker", and "stronger" are selected as the heat retention temperature (set temperature in the refrigerator). It may be provided, and may be configured so that the heat retention temperature (set temperature in the refrigerator) can be indicated (selected) by numerical values. For example, a configuration may be adopted in which the heat retaining temperature (set temperature in the refrigerator) is automatically set according to the food type input by the user.
Instead of fixing the heat retention time to 30 minutes, the maximum heat retention time may be changed depending on the type of food or weight.

In the above embodiment, the temperature sensor 8 detects the inside temperature of the refrigerator. However, the temperature sensor 8 may directly detect the temperature of the food to control the warming operation. Corresponds to item 3). In addition, the user may set the warming time during the warming operation by a dial operation or the like. At this time, from the viewpoint of reliably preventing the deterioration of food quality, the maximum warming time is also set to 30.
Minutes is desirable (corresponding to claim 5). Furthermore, in this case, in order to prevent the food from being overheated during the warming operation, it is desirable to control the warming operation while setting the upper limit of the temperature of the cooking chamber 1 to 150 ° C. (corresponding to claim 6).

In addition, the heater heating means is not limited to the upper heater 3 and the lower heater 4, and a heater may be provided on the side surface or the back surface of the cooking chamber, and some of them may be combined. A heater for supplying hot air may be employed. Further, the present invention can be applied to a heating cooker that does not have a microwave cooking function (magnetron) and performs heating cooking exclusively with a heater, or a heating cooker dedicated to heat retention.

[0062]

As is clear from the above description, the heating cooker of the present invention has a heat retaining function of controlling the heater heating means to keep the object to be heated in the heating cooking chamber at a predetermined temperature. In the device, a heat insulation operation control means capable of executing the heat insulation operation at a plurality of different heat insulation temperatures is provided, so that the heat insulation can be performed according to the type and amount of the object to be heated or the user's preference. It has an excellent practical effect of being able to do so.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of the present invention, and is a flowchart showing a control procedure at the time of a warming operation.

FIG. 2 is a diagram schematically showing a configuration of a heating cooker.

FIG. 3 is a front view of an operation panel.

FIG. 4 is a diagram showing constants such as a set temperature.

FIG. 5 is a diagram showing the relationship between the temperature in the refrigerator and the temperature of food with the lapse of time during the heat retention operation.

FIG. 6 is a graph showing a case where the power cutoff cycle of the heater is set to 30 seconds;
Diagram showing how the internal temperature fluctuates with seconds

FIG. 7 is a diagram showing the results of a sensory test

FIG. 8 is a view corresponding to FIG. 1, showing a second embodiment of the present invention.

FIG. 9 is a diagram corresponding to FIG. 2;

FIG. 10 is a view corresponding to FIG. 4, showing a third embodiment of the present invention;

FIG. 11 is a view corresponding to FIG. 2, showing a fourth embodiment of the present invention;

FIG. 12 is a view corresponding to FIG. 1, showing a fifth embodiment of the present invention;

FIG. 13 is an enlarged front view showing a display unit.

FIG. 14 is a view corresponding to FIG. 1, showing a sixth embodiment of the present invention.

[Explanation of symbols]

In the drawings, 1 is a cooking chamber, 3 is an upper heater (heater heating means), 4 is a lower heater (heater heating means), 8 is a temperature sensor (inside temperature detecting means), 9 is an operation panel, and 10 is a display unit. , 11 is an operation unit, 14 is a "warm storage" key, 15 is a finishing adjustment key, 17 is a control circuit (heat keeping operation control means), 2
1 denotes a weight sensor (weight detecting means), and 24 denotes a rotating plate.

Claims (15)

[Claims] 1. A heating chamber in which an object to be heated is disposed, a heater heating means for heating the object to be heated in the heating chamber, and a heating temperature controlled by controlling the heater heating means to a predetermined temperature. A heating cooker comprising: a heat-retaining operation control means for maintaining the temperature of the heating cooker, wherein the heat-retention operation control means is configured to be able to execute the heat-retaining operation at a plurality of different heat-retaining temperatures. 2. The apparatus according to claim 1, further comprising: an inside temperature detecting means for detecting a temperature of the cooking chamber, wherein the heat keeping operation control means controls the heater heating means based on the detection of the inside temperature detecting means. Item 2. A heating cooker according to Item 1. 3. The apparatus according to claim 1, further comprising a food temperature detecting means for detecting a temperature of the object to be heated, wherein the heat keeping operation control means controls the heater heating means based on the detection of the food temperature detecting means. The heating cooker as described. 4. The heating cooker according to claim 1, wherein an upper limit is set for a duration of the warming operation. 5. The heating cooker according to claim 4, wherein the duration of the warming operation can be set within 30 minutes. 6. The cooking device according to claim 5, wherein the heat retention operation control means sets the upper limit of the temperature in the cooking chamber to 150 ° C. 7. The apparatus according to claim 1, further comprising weight detection means for detecting a weight of the object to be heated, wherein the heat retention operation control means automatically sets the heat retention temperature according to the weight detected by said weight detection means. 7. The cooking device according to any one of items 1 to 6. 8. The heater according to claim 1, wherein the heater heating means comprises a heater for heating the object to be heated by radiant heat.
A cooking device according to any one of claims 1 to 7. 9. The heater heating means includes a plurality of heaters provided at different positions, and the heat keeping operation control means includes:
The heating cooker according to any one of claims 1 to 8, wherein the heat retention operation is performed by alternately controlling the plurality of heaters to be turned off and on. 10. The heating cooker according to claim 9, wherein the heat retention operation control means repeats the power cutoff control of the plurality of heaters in a short cycle of 30 seconds or less. 11. The cooking method according to claim 9, wherein the energization time of the heater located on the front side of the food is shorter than the energization time of the heater located on the side of the container supporting the food. vessel. 12. The cooking device according to claim 9, wherein the higher the heat retention temperature, the shorter the energization time of the heater located on the front side of the food. 13. The heating cooker according to claim 1, wherein a rotating plate on which the object to be heated is placed is rotated during the heat keeping operation. 14. The cooking device according to claim 1, wherein when the heat retaining operation is performed, a message indicating that the temperature of the container supporting the food is high is displayed. 15. The heating device according to claim 1, wherein the heat-retaining operation control means does not energize the heater heating means when the initial temperature in the cooking chamber is higher than a predetermined temperature. Cooking device.