JPH0548124B2 - - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is directed to a rice cooker that can selectively perform a rice porridge cooking operation in addition to a rice cooking operation, and in particular, a rice cooker that can selectively perform a rice porridge cooking operation in addition to a rice cooking operation. The present invention relates to a heating control method for an electric rice cooker, which is equipped with a heat-sensitive element that detects when rice has reached a boiling state, and uses the output of the heat-sensitive element to control rice cooking.

(Prior art) In recent years, electric rice cookers have various rice cooking controls, specifically, when cooking white rice, the rice cooking heater is used as a heating means only until the water in the pot boils. By generating heat in the boiler, it satisfies the well-known condition of "medium boiling", which is one of the conditions for deliciously cooking rice, and reduces the heater output after boiling to prevent boiling over or burning of the rice. control to prevent rice from boiling and to cook rice deliciously,
Alternatively, when cooking rice porridge, after the water in the pot has boiled, the output of the rice cooking heater is reduced to prevent rice from boiling over.

(Problem to be Solved by the Invention) However, in the conventional configuration described above, the pot temperature when reducing the heater output to prevent boiling over is the same temperature both when cooking white rice and when cooking porridge. Therefore, especially when cooking rice porridge, which tends to boil over because the amount of water is large compared to the amount of rice, there is a drawback that boiling over cannot be sufficiently prevented.

The present invention has been made in view of the above circumstances, and its purpose is to effectively prevent boiling over from the inside of the pot when controlling rice cooking such as white rice or porridge cooking using an electric rice cooker, and in particular to prevent boiling over from boiling over. When cooking rice porridge, where rice porridge is more likely to occur, the operation of reducing the heater output is performed earlier than when cooking white rice, which further enhances the effect of preventing boiling over.Moreover, when cooking white rice, the amount of rice cooked differs in size. To provide a heating control method for an electric rice cooker, which makes it possible to strictly control rice cooking even when the rice is cooked to a good degree at all times.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides an electric rice cooker that can selectively execute a rice porridge cooking course in addition to a white rice cooking course, in which a pot is heated. The method is configured to reduce the heating output when the detected temperature of the heat-sensitive element for detecting the boiling state of the pot reaches a predetermined target temperature below the boiling temperature after the start of energization to the heating means for cooking the porridge. When executing a rice cooking course, the target temperature is changed to be lower than when executing a rice cooking course for cooking white rice, and when executing a rice cooking course for cooking white rice, the target temperature is changed to be higher as the amount of rice cooked is larger. It is something.

(Function) When executing either the rice cooking course for cooking white rice or the rice cooking course for cooking porridge, the temperature detected by the heat-sensitive element rises after the heating means for heating the pot starts energizing, and the temperature reaches a predetermined target temperature below the boiling temperature. When reached, the heating power is reduced. As a result, excessive boiling in the pot is suppressed and boiling over is prevented. At this time, since the amount of water is relatively large when executing the rice porridge cooking course,
In this case, the target temperature is changed to be lower than when executing the rice cooking course for cooking white rice, so that the heating means described above starts reducing the output as soon as possible. As a result, the effect of preventing boiling over can be reliably obtained. Furthermore, when executing a rice cooking course for cooking white rice, the target temperature is changed to become higher as the amount of rice cooked is larger, so the timing of reduction of heating output is adjusted to be delayed as the amount of rice cooked is larger. . As a result, the time from when the heating output decreases until the inside of the pot reaches a boiling state becomes constant regardless of the amount of rice being cooked (that is, the heat capacity of the object to be heated), so rice cooking control can be controlled regardless of the amount of rice being cooked. It becomes possible to cook the rice strictly regardless of the restrictions, and the rice is always well-cooked.

(Example) In Fig. 2, 1 is the rice cooker body consisting of an inner frame 2 and an outer frame 3, etc., 4 is a lid, 5 is a pot removably housed in the inner frame 2, and 6 is this pot 5. The heating means installed in the space between the bottoms of the inner frame 2 and the outer frame 3 for heating is, for example, a heater for cooking rice with a rated output of 600 watts. Reference numeral 7 denotes a heat-sensitive cap that is arranged so as to be able to move up and down so as to penetrate through the bottom of the inner frame 2. This cap is always urged upward by the spring force of a compression coil spring 8, so that the pot 5 is not moved inside. It is arranged so as to come into pressure contact with the outer bottom of the pot 5 while being housed in the frame 2. Reference numeral 9 denotes a heat-sensitive element such as a thermistor installed in the heat-sensitive cap 7 to detect the temperature of the pot 5, and 10 indicates only when the pot 5 containing rice and water is installed in the inner frame 2. This is a pot switch that is turned on by being pressed by a heat-sensitive cap 7 to prevent dry cooking. Also, 11
is the operation panel installed on the side of the rice cooker body 1,
Reference numeral 12 denotes a case disposed at the outer bottom of the rice cooker main body 1, and inside this case 12 there is a control for controlling power on/off of the heater 6 based on the temperature detected by the thermistor 9 and input from the operation panel 11. circuit 1
3 is stored.

FIG. 1 shows the configuration of the control circuit 13 and its related parts that are directly related to the gist of the present invention, and will be described below.

That is, 14 is a switching element, for example, a triax, which is connected between both terminals of an AC power source 15 via the heater 6 and the pot switch 10 in series. 16 is a light emitting diode 16a
A photocoupler consisting of a phototransistor 16b and a phototransistor 16b is configured so that a half-wave voltage of an AC power supply 15 is applied to the light emitting diode 16a via a diode 17 and a resistor 18. Reference numeral 19 denotes a DC constant voltage circuit that receives the output of the AC power supply 15, and power is supplied to each circuit section described below from its output lines La and Lb.

20 is an initialization circuit consisting of, for example, a differential circuit;
This outputs an initialization pulse P ₀ every time the power is turned on. 21 is a waveform shaping circuit that shapes the output of the photocoupler 16 (voltage output corresponding to the half-wave output of the AC power source 15) into a rectangular wave, and 22 is a waveform shaping circuit that divides the output of this waveform shaping circuit 21 to produce a time signal, for example 1. A first frequency divider circuit 23 generates a clock pulse P ₁ with a period of seconds, and a second frequency divider 23 divides the frequency of the clock pulse P ₁ and outputs a clock pulse P ₂ with a period of 10 seconds, which is also a time signal. . Reference numeral 24 denotes an A-D converter which together with the thermistor 9 constitutes a temperature detection means 25, which outputs a digital temperature detection signal Sd corresponding to the temperature of the pot 5 detected by the thermistor 9.

26 and 27 are first and second temperature value storage units that store values corresponding to temperatures used to detect the amount of cooked rice, such as 70°C and 80°C, respectively; 28 is a predetermined lower limit temperature, such as 90°C; A third temperature value storage unit 29 that stores a corresponding value is, for example, 110°C.
a fourth temperature value storage unit that stores a numerical value corresponding to . Also, 30 to 39 are the 5th to 14th
As shown in FIG. 1, the temperature value storage section stores, for example, the following numerical values. That is, the fifth temperature value storage unit 30 stores a value corresponding to 2°C, and the sixth temperature value storage unit 3 stores a value corresponding to 2°C.
1 stores a value corresponding to 115℃ as the heater power-off temperature Dzo during porridge cooking operation,
The seventh and tenth temperature value storage units 32 and 35 respectively store numerical values corresponding to 1°C.
The 11th temperature value storage units 33 and 36 each store a numerical value corresponding to 3°C, the 9th and 12th temperature value storage unit 34 and 37 store a numerical value corresponding to 5°C, respectively, and the 13th temperature value storage unit 34 and 37 store a numerical value corresponding to 5°C, respectively. The temperature value storage unit 38 stores 112 as the heater power-off temperature Dzh during the white rice cooking operation.
A numerical value corresponding to °C is stored, and the 14th temperature value storage section 39 stores 103 as the temperature Dr for starting double cooking.
A numerical value corresponding to °C is stored.

Reference numerals 40 and 41 denote first and second time value storage units that store numerical values corresponding to, for example, 2 minutes and 4 minutes, respectively, which serve as standards when detecting the amount of cooked rice. Reference numerals 42 to 52 are third to thirteenth time value storage sections, in which, as shown in FIG. 1, for example, the following numerical values are stored. That is, the third time value storage unit 42 stores a numerical value corresponding to 7 minutes,
A numerical value corresponding to 9 minutes is stored in the fourth time value storage section 43, a numerical value corresponding to 0 seconds is stored in the fifth and eighth time value storage sections 44 and 47, respectively,
Numerical values corresponding to 10 seconds are stored in the sixth and ninth time value storage units 45 and 48, respectively.
The ten time value storage units 46 and 49 each store a numerical value corresponding to 20 seconds, and the eleventh time value storage unit 50 stores a numerical value corresponding to 20 seconds.
A numerical value corresponding to 30 seconds as the double cooking heating reference time N is stored, a numerical value corresponding to 15 minutes as the uneven operation time M is stored in the 13th time value storage section 52, and a numerical value corresponding to 15 minutes as the uneven operation time M is stored in the 12th The time value storage unit 51 stores a numerical value corresponding to 30 minutes as the porridge cooking heating time MD.

53 to 66 are comparison circuits, which output a high level signal from the output terminal C when the respective input values to the input terminals A and B are in the relationship A≧B, and when A<B
A low level signal is output from the output terminal C when the relationship is as follows. Further, 67 is a comparison circuit equipped with an enable terminal En.
It performs the same operation as the comparator circuits 53 to 66 only when receiving a high level signal at the enable terminal En, and always outputs a low level signal from the output terminal C when receiving a low level signal at the enable terminal En. 68 is a subtraction circuit which subtracts the input value to the input terminal E from the input value to the input terminal D, and outputs the result of the subtraction from the output terminal F. 6
Addition circuits 9 to 72 add the input value to the input terminal X and the input value to the input terminal Y, and output the addition result from the output terminal Z.
73 to 77 are counters that count the number of input pulses to the clock terminal CK and output the counted value from the output terminal Q, and the count contents are initialized when a pulse signal is received at the reset terminal R. ing. In this case, the counter 77 corresponds to a timer element according to the present invention. 78 to 81 are trigger circuits that generate a short trigger pulse when the input signal rises.
Output P ₃ . 82 is a delay circuit which delays the input signal for a short time and outputs the delayed signal.

83 is a shift register having, for example, 24 unit registers, and this shifts the input to the data terminal D to the first register every time a pulse signal is received at the clock terminal φ.
The data is read into the unit register 83a and stored therein, and each time new data is read, the old stored data is sequentially shifted to the upper unit register.When a pulse signal is received at the reset terminal R, The stored data is initialized. And such a shift register 8
3, for example, the seventh unit register 83b, the 12th unit register 83c, and the 15th unit register 83b,
th unit register 83d, 18th unit register 83e, 21st unit register 83f,
It is configured to output each data stored in the 24th unit register 83g. 84 is a heater drive circuit that outputs a gate signal Sg and supplies it to the gate terminal of the triac 14 only when receiving a high level signal; 85 is a duty ratio control circuit that is driven only when receiving a high level signal; The ratio control circuit 85 receives, for example, a pulsed control signal Sc with a duty ratio of 50% when it is driven.
Output. Reference numerals 86 to 106 designate transfer gates, which are rendered conductive only when receiving a high level signal at their gate terminals.

Reference numerals 107, 108 and 109 are respectively provided on the operation panel 11, and are a start switch for starting the rice cooking operation, a porridge cooking operation selection switch, and a stop switch for stopping the rice cooking operation, and these are composed of momentary type push button switches.
Only when turned on, pulse signals (high level signals) P ₄ , P ₅ and P ₆ are output to the corresponding lines, respectively. Further, 110 to 113 are R-S flip-flops, 114 to 128 are AND circuits, 1
29 to 132 are OR circuits, and 133 to 138 are inverters.

Note that the first and second frequency dividing circuits 22, 23 and
A clock means 139 is configured by the AND circuit 117, which includes first and second temperature value storage sections 26 and 27, first and second time value storage sections 40 and 41, and a comparison circuit 5.
3, 54, 57, 58, counter 73, AND circuits 114, 118, and inverters 132, 133
The rice cooking amount detection means 140 is constituted by the first
temperature value storage unit 28, fifth temperature value storage unit 30,
Comparison circuits 55, 67, subtraction circuit 68, delay circuit 8
2. A boiling detection means 141 is constituted by the shift register 83 and the transfer gates 86 to 87 and 101 to 106. Also, a heater drive circuit 84, a duty ratio control circuit 85, an R-S flip-flop 112, an AND circuit 121, 122,
A heater output control means 142 is configured by the OR circuit 130 and the inverter 137, and includes a fourteenth temperature value storage section 39 and fifth to twelfth time value storage sections 44.
~51, comparison circuits 62 to 64, addition circuits 71, 7
2, counters 75, 76, trigger paths 79, 80,
Transfer gates 95-100, AND circuit 1
23, 124 and the inverter 138 constitute a double cooking control means 143, and a comparison circuit 61,
R-S flip-flop 113, addition circuit 69,
70, the seventh to thirteenth temperature value storage units 32 to 38 and transfer gates 89 to 94 constitute a first rice cooking end control means 144, and the sixth temperature value storage unit 31 and the thirteenth time value Storage unit 52, comparison circuits 65, 66, counter 7 as a timer element
7. Transfer gate 88, AND circuit 126
~128, the second rice cooking end control means 145 is constituted by the OR circuit 132, the third and fourth time value storage sections 42, 43, the comparison circuits 59, 60, the counter 74, the AND circuits 115, 119, 120 and inverters 135 and 136, the correction means 1
46 are configured.

In particular, the R-S flip-flop 111 is
This is for storing the selected state of the rice cooking operation and the porridge cooking operation, and the set state corresponds to the selected state of the polished rice cooking action, and the reset state corresponds to the selected state of the porridge cooking action.

Next, the effects of the above configuration will be explained in Figures 3 to 6.
This will be explained with reference to the figures. 3A and 3B show the temperature detected by the thermistor 9 (i.e. the temperature of the pot 5) and the output of the heater 6 over time, respectively, when the white rice cooking operation is selected, and FIG. , the comparator circuit 5 in the same selection state
3, 54, 55, 56, 61, 62, 63, 6
4, 67, duty ratio control circuit 85, start switch 107, R-S flip-flop 11
0, 112, 113 each set output terminal Q, R-
Reset output terminal Q of S flip-flop 111, AND circuits 114, 115, 120, 122,
123, 125, and the output waveforms from the OR circuit 130 are shown in correspondence with their respective codes. Furthermore, the fifth
Figures A and B show the temperature detected by the thermistor 9 and the time change characteristics of the output of the heater 6 when the porridge cooking operation is selected, respectively, and Figure 6 shows the comparison circuit 53 and the output of the heater 6 in the selected state. 5
4, 55, 67, trigger circuit 80, duty ratio control circuit 85, start switch 107, porridge cooking operation selection switch 108, each set output terminal Q of R-S flip-flops 110, 111, 112, 113, AND circuits 114, 115 ,12
0, 122, 125, 128, and the respective output waveforms from the OR circuit 130 are shown in correspondence with their respective codes.

That is, when the pot 5 containing rice and the required amount of water is mounted in the inner frame 2, the pot switch 10 is turned on in response to the mounting. When the power is turned on in this state, the DC power supply circuit 19 and the photocoupler 16 are driven, and the initialization pulse P ₀ is output from the initialization circuit ₂₀ .
R-S flip-flops 110 and 11 by
1 is reset. Therefore, the high level signal output from the reset output terminal of the R-S flip-flop 110 causes the counters 73, 7 to
5 is initialized, and the R-S flip-flop 113 is reset. In addition, since the R-S flip-flop 111 is reset as described above, the white rice cooking operation is selected, but when selecting the porridge cooking operation from this state, the porridge cooking operation selection switch must be pressed. 108
Turn on. Then, at this point, AND circuit 1
16 receives a high level signal from the reset output terminal of the R-S flip-flop 110 and is in a signal passage permitting state, so that the pulse signal P ₅ output in response to the ON of the porridge cooking operation selection switch 108 is output to the AND circuit 116. After passing through, the R-S flip-flop 111 is set.
The porridge cooking operation is now selected.

First, the operation when the white rice cooking operation is selected will be described. That is, while the R-S flip-flop 111 remains reset, at time t ₀
When the start switch 107 is turned on (see FIGS. 3 and 4), the R-S flip-flop 110 is set by the pulse signal _P4 output in response to the turn-on, and the R-S flip-flop 110 is set. Flip-flop 112 is reset. As a result,
A high level signal from the set output terminal Q of the R-S flip-flop 110 is applied to the AND circuit 121,1.
22. At this time, one AND circuit 121 receives the R-S reset as described above.
Since the low level signal from the set output terminal Q of the flip-flop 112 is applied, its output remains a low level signal. Since the level signal is inverted to a high level signal by the inverter 137 and is also provided with a high level signal from the reset output terminal of the R-S flip-flop 113 which is also in the reset state, as a result, the AND circuit is A high level signal is output from 122 and applied to the heater drive circuit 84. For this reason, the gate signal Sg is output from the heater drive circuit 84 to turn on the triax 14, and in response, electricity is supplied from the AC power supply 15 to the heater 6 via the pot switch 10 and the triax 14 to heat the pot 5. Then, the rice cooking process for the white rice cooking operation starts.

Incidentally, once the rice cooking process for such a white rice cooking operation is started, the AND circuit 116 becomes R-
Since the low level signal from the reset output terminal of the S flip-flop 110 is received and the passage of the signal is blocked, even if the porridge operation selection switch 108 is turned on, the R-S flip-flop 111 remains in the set state (in the porridge operation). (selected state) is now prevented.

As the rice cooking process for cooking white rice progresses as described above, the temperature of the pot 5 rises as shown in FIG. Output. and,
When the temperature of the pot 5 rises to 70° C. stored in the first temperature value storage unit 26 (time t ₁ ), the rice cooking amount detection means 140 operates first. That is, in the rice cooking amount detection means 140, the comparison circuit 53 determines that the temperature detection signal Sd input to its terminal A is "70" input to the terminal B from the first temperature value storage section 26.
A low level signal is output until time t ₁ when the temperature value becomes equal to the temperature value corresponding to "°C", and a high level signal is output after that time t ₁ . In addition, the comparison circuit 54
is a high level signal until time _t2 when the temperature detection signal Sd input to the terminal B becomes larger than the temperature value corresponding to "80°C" input from the second temperature value storage section 27 for the terminal A. and output that time t ₂
After that, a low level signal is output. Therefore, the time
Since high level signals are output from both comparison circuits 53 and 54 and given to the AND circuit 114 only during the period t ₁ to t ₂ , the first frequency dividing circuit 22 is output only during this period.
The pulse signal _P1 with a period of 1 second from the AND circuit 11
4 and is applied to the clock terminal CK of the counter 73. Therefore, as a result, the count value of the counter 73 is the time Ta required for the temperature of the pot 5 to rise from 70°C to 80°C (time from time t ₁ to t ₂ ).
The value corresponds to . The time Ta measured as above has the property of increasing or decreasing in proportion to the amount of rice cooked.
The amount of cooked rice is determined based on the count value of the counter 73 corresponding to this time Ta. That is,
The count value of the counter 73 is the comparison circuit 57, 58
is compared with each numerical value (corresponding to 2 minutes and 4 minutes) stored in the first and second time value storage sections 40 and 41, respectively. At this time, the comparator circuit 57 outputs a low level signal when the count value of the counter 73 is smaller than the value equivalent to 2 minutes (in other words, when the amount of rice cooked is relatively small), and this low level signal is sent to the inverter 133 to cook the rice. The signal is inverted to a high level signal which is a quantity signal and is applied to line _L1 . Furthermore, when the count value of the counter 73 is equal to or greater than the value equivalent to 4 minutes (in other words, when the amount of cooked rice is relatively large), the comparison circuit 58 outputs a high level signal as a rice cooking amount signal and supplies it to the line _L3 . Furthermore, the counter 73
When the count value is equal to or greater than the value equivalent to 2 minutes and smaller than the value equivalent to 4 minutes (in other words, when the amount of rice cooked is medium), a high level signal is output from the comparator circuit 57, and this is sent to one side of the AND circuit 118. A low level signal is output from the comparator circuit 58, which is inverted to a high level signal by the inverter 134 and is then applied to the other input terminal of the AND circuit 118. As a result, the AND A high level signal, which is a rice cooking amount signal, is output from the circuit 118 and applied to line _L2 .
In short, the rice cooking amount detecting means 140 determines the size of the rice cooking amount based on the time required for the temperature of the pot 5 to rise from 70°C to 80°C, and the rice cooking amount signal (high level signal ) to line L ₁ ,
It selectively outputs to L ₂ and L ₃ . and,
In this way, when the detected amount of cooked rice is relatively small, the transfer gates 86, 89, and 95 whose gate terminals are connected to the line _L1 are in a conductive state, and when the detected amount of cooked rice is medium, Transfer gate 8 with gate terminal connected to line L ₂
7, 90, and 96 are conductive, and when the detected amount of cooked rice is relatively large, the gate terminal is connected to the line.
Transfer gates 88, 91, connected to L ₃
97 becomes conductive. In this case, when the rice cooking operation is selected, that is, when the R-S flip-flop 111 is reset, the transfer gates 102 and 104 receive a high level signal from the reset output terminal at their gate terminals. , 106 become conductive.

Note that the temperature values stored in the seventh, eighth, and ninth temperature value storage sections 32, 33, and 34 corresponding to the transfer gates 89, 90, and 91 that are selectively turned on as described above are those for cooking white rice. Temperature for heater power outage
It is for adjusting Dzh (the temperature value stored in the 13th temperature value storage unit 38, that is, 112°C),
Each of these stored temperature values is input to the input terminal Y of the adder circuit 69.
The temperature value inputted in this manner is selectively given to the temperature value according to the magnitude of the detected amount of cooked rice. It is added to the electric power temperature Dzh) and output. Furthermore, fifth, sixth, and seventh time value storage units 44, 4 corresponding to the transfer gates 95, 96, 97 which are selectively turned on as described above are also provided.
The time values stored in 5 and 46 are for adjusting the double cooking heating reference time N (the time value stored in the 11th time value storage unit 50, that is, 30 seconds),
Each of these storage time values is input to the input terminal Y of the adder circuit 71.
The time value inputted in this manner is selectively given to the amount of cooked rice according to the magnitude of the detected amount of cooked rice. It is added to the cooking heating standard time N) and output.

Thereafter, when the temperature of the pot 5 further increases and becomes equal to or higher than the lower limit temperature "90°C" stored in the third temperature value storage section 28 (time t ₃ ), each of the input terminals A and B of the comparator circuit 55 When the input values meet the relationship A≧B, the output of the comparison circuit 55 is inverted to a high level signal. As a result, the AND circuit 117 receives the high level signal at one input terminal.
is the input to the other input terminal, that is, the clock means 1
The pulse signal _P2 having a period of 10 seconds from the second frequency dividing circuit 23 in the third frequency dividing circuit 39 is allowed to pass through. Also,
At the same time, a high level signal from the comparator circuit 55 is passed through the delay circuit 82 to the enable terminal.
The comparator circuit 67 received by En becomes operational, and a trigger pulse is generated from the trigger circuit 81 which also receives a high level signal from the comparator circuit 55.
_P3 is output, the shift register 83 is initialized, and the boiling detection means 1 is activated accordingly.
41 boiling detection function is now enabled.

That is, when the pulse signal P ₂ begins to pass through the AND circuit 117, the pulse signal P ₂ comes to be applied to the clock terminal φ of the shift register 83. Temperature detection signal Sd 10
It is read and stored every second, and each time a new temperature detection signal Sd is read, the old temperature detection signal Sd is sequentially shifted to a higher unit register.
As a result, the seventh unit register 83b contains:
The temperature detection signal Sd 70 seconds before the current temperature detection signal Sd is stored and stored in the 12th unit register 8.
3c stores the temperature detection signal Sd 120 seconds (2 minutes) before the current temperature detection signal Sd, and the 15th unit register 83d stores the temperature detection signal Sd 150 seconds (2 minutes) before the current temperature detection signal Sd. Temperature detection signal before (minute 30 seconds)
Sd is stored in the 18th unit register 83e.
180 seconds (3 seconds) from the current temperature detection signal Sd.
The temperature detection signal Sd 210 seconds (3 minutes 30 seconds) before the current temperature detection signal Sd is stored in the 21st unit register 83f.
is stored, and the 24th unit register 83g stores 240 seconds (4 minutes) from the current temperature detection signal Sd.
The previous temperature detection signal Sd is now stored.
At this time, each of the stored data in the unit registers 83b to 83g is applied to the input terminal E of the subtraction circuit 68 via the corresponding transfer gates 101 to 106 and 86 to 88. is selected, transfer gates 102, 104, 10 are selected as described above.
6 is in a conductive state, unit register 8
Memory data of 3c, 83e, 83g (2 minutes ago, 3
The temperature detection signals Sd) from 1 minute ago and 4 minutes ago are now ready to be output. Further, as described above, when the amount of cooked rice is relatively small, the transfer gate 86 is in a conductive state, and the data stored in the unit register 83c is applied to the input terminal E of the subtraction circuit 68.
Similarly, when the amount of cooked rice is medium or relatively large, the data stored in the unit registers 83e and 83g are applied to the input terminal E of the subtraction circuit 68, respectively. The temperature detection signal Sd is directly input to the other input terminal D of the subtraction circuit 68, and therefore the subtraction circuit 68 calculates the reference time from the value indicated by the current temperature detection signal Sd. The value indicated by the temperature detection signal Sd 2 minutes ago, 3 minutes ago, or 4 minutes ago is subtracted.
The temperature rise value of the pot 5 within 3 minutes, 3 minutes, or 4 minutes) is a value corresponding to the temperature gradient of the pot 5 over time.

Therefore, the temperature of the pot 5, that is, the rate of increase of the temperature detection signal Sd has a property that as the water in the pot 5 approaches a boiling state, it gradually decreases and finally reaches approximately zero. If it is detected that the temperature rise value of the pot 5 within the reference time has become equal to or less than a predetermined comparative temperature value, it can be determined whether the inside of the pot 5 has reached a boiling state. In this case, since the temperature increase rate of the pot 5 tends to be slower as the amount of rice cooked increases, in order to accurately detect boiling, it is desirable to change the above reference time according to the amount of rice cooked. Now, in order to perform accurate temperature detection in this way, the reference time (i.e., the sampling time of the temperature detection signal Sd) is set to 2 as described above.
The time is set to automatically change to either minute, 3 minutes, or 4 minutes. Then, in the comparison circuit 67, the output from the subtraction circuit 68 (the temperature rise value of the pot 5 within the three-step reference time determined according to the amount of rice cooked) and the fifth temperature value storage section 30 are stored for comparison. The value stored as the temperature value (equivalent to 2°C) is compared, and when the temperature rise value of the pot 5 within the above reference time is less than 2°C, in other words, the temperature rise of the pot 5 When the gradient becomes below a predetermined target temperature gradient (that is, when the temperature of the pot 5 reaches a predetermined target temperature below the boiling temperature), the boiling detection signal Sz consisting of a high level signal is output from the comparator circuit 67. is output (time t ₄ ).

Now, when the boiling detection signal Sz is output as described above, the heater output control means 142 functions. That is, depending on the output of the boiling detection signal Sz, R
- Since the S flip-flop 112 is set, it was outputting a high level signal until then.
The output of the AND circuit 122 is inverted to a low level signal, and R is applied to each input terminal of the AND circuit 121.
High level signals are applied from the set output terminals Q of the -S flip-flops 110 and 112 and the reset output terminal of the R-S flip-flop 113, and a high level signal is output from the AND circuit 121. In response, the duty ratio control circuit 85 outputs a pulsed control signal Sc with a duty ratio of 50%, and the heater drive circuit 8
4 will be given. As a result, the triax 14 is turned on and off at a duty ratio of 50%, and since the rated output of the heater 6 is 600 watts, the heater 6 generates heat at an output of 300 watts, which is half the rated output. It becomes like this.

Further, when the R-S flip-flop 112 is set at the time _t4 , the trigger circuit 78
is driven and the trigger pulse P ₃ is output from now on, so the counters 74 and 77 are initialized by the trigger pulse P ₃ . At this time, the R-S flip-flops 111, 113
An AND circuit 120 receiving high level signals from each reset output terminal outputs a high level signal. Also, at this point, there is still enough water left in the pot 5 and the temperature does not reach 100°C, so the temperature detection signal Sd and the fourth temperature value corresponding to the temperature of the pot 5 are The comparison circuit 56 that compares the value stored in the storage unit 29 (corresponding to 110° C.) outputs a high level signal, and therefore the AND circuit receives the high level signal as well as the high level signal from the AND circuit 120. 115 is in a state where the pulse signal P ₁ (1 second period) from the first frequency dividing circuit 22 is allowed to pass. Therefore, the count value of the counter 74 initialized as described above is
It will show the elapsed time since t ₄ .

Note that the AND circuit 126 corresponding to the other counter 77, which is initialized at the same time as the counter 74, includes:
A low level signal from the set output terminal Q of the R-S flip-flop 111 is applied, and the
Since passage of the pulse signal _P1 is blocked by the AND circuit 126, the counting operation of the counter 77 does not proceed, and as a result, the second rice cooking end control means 145 for controlling the porridge cooking operation does not function.

When the rice cooking process further progresses and the inside of the pot 5 enters a so-called dry-up state, the temperature of the pot 5 will rise rapidly.In this case, the temperature of the pot 5 will rise at time _t5 . When the temperature reaches 110°C, the input terminals A and B of the comparator circuit 56 have a relationship of A<B, and the output is inverted to _a low level signal. As a result, the counting operation of the counter 74 is stopped. Therefore, as a result, the count value of the counter 74 indicates that the temperature of the pot 5 is 110°C from time _t4 when the boiling detection signal Sz is output.
This corresponds to the time Tb (corresponding to the duration of the boiling state) until time t ₅ is reached.

Like the time Ta from time t ₁ to t ₂ described above, the time Tb measured as above has the property of increasing or decreasing in proportion to the amount of rice cooked, and is also influenced by the ratio of rice to water during cooking. The correction means 14
6 corrects the rice cooking amount detected by the rice cooking amount detection means 140 as follows based on the count value of the counter 74 corresponding to the time tb. That is, the count value of the counter 74 is compared with each numerical value (corresponding to 7 minutes and 9 minutes) stored in the third and fourth time value storage sections 42 and 43 by comparison circuits 59 and 60, respectively. At this time, the comparison circuit 59
When the count value of 4 is smaller than the value equivalent to 7 minutes (in other words, when the amount of cooked rice is relatively small), a low level signal is output, and this low level signal is inverted to a high level signal by the inverter 135, and the line _L4 is inverted. given to. Further, the comparison circuit 60 outputs a high level signal and supplies it to the line _L6 when the count value of the counter 74 is equal to or greater than the value equivalent to 9 minutes (in other words, when the amount of cooked rice is relatively large). and,
When the count value of the counter 74 is equal to or greater than the value equivalent to 7 minutes and smaller than the value equivalent to 9 minutes (in other words, when the amount of rice cooked is medium), a high level signal is output from the comparator circuit 59 and this is sent to the AND circuit 119. A low level signal is output from the comparator circuit 60, which is inverted to a high level signal by the inverter 136, and the AND
The signal is applied to the other input terminal of the circuit 119, and as a result, a high level signal is output from the AND circuit 119 and applied to the line _L5 .

When the amount of cooked rice detected in this way is relatively small, the transfer gates 92 and 98 whose gate terminals are connected to the line _L4 are in a conductive state, and when the detected amount of cooked rice is medium, If the transfer gates 93 and 99 whose gate terminals are connected to the line _L5 are in a conductive state, and the detected amount of cooked rice is relatively large, the gate terminals are connected to the line L5.
Transfer gate 94,10 connected to L ₆
0 becomes conductive. At this time, the 10th, 11th, and 12th transfer gates correspond to the transfer gates 92, 93, and 94 that are selectively turned on as described above.
The temperature values stored in the temperature value storage units 35, 36, and 37 are also used to correct the heater power-off temperature Dzh (the temperature value stored in the 13th temperature value storage unit 38, that is, 112°C). , and each of these stored temperature values corresponds to the input terminal Y of the adder circuit 70 for the above-mentioned time Tb.
The adder circuit 70 is selectively given depending on the length of
In the case of
Dzh by a temperature value corresponding to the amount of cooked rice detected by the rice cooking amount detection means 140), and then the rice cooking amount detection means 140
It acts to correct the added temperature value and thus the detected rice cooking amount. Further, eighth, ninth, and tenth time value storage units 47, corresponding to the transfer gates 98, 99, and 100 that are also selectively turned on,
The time values stored in 48 and 49 are also the double cooking heating reference time N (11th
The time value stored in the time value storage unit 50, that is, 30
These memory time values are selectively given to the input terminal Y of the adder circuit 72 according to the length of the time Tb. A numerical signal from the addition circuit 71 is obtained by adding the time value inputted to the time value to the double-cooking heating reference time N by the time value corresponding to the amount of cooked rice detected by the rice amount detection means 140. The added time value by the rice cooking amount detection means 140 and the detected rice cooking amount are thereby corrected.

At the subsequent time _t6 , the first rice cooking end control means 144 functions. That is, the temperature of the pot 5 is the cooked rice temperature Doff corresponding to the output from the adder circuit 70 (i.e., the heater power-off temperature Dzh (112°C)
, the temperature value corresponding to the amount of cooked rice detected by the rice cooking amount detection means 140 and the temperature value corrected by the correction means 146 is reached), each input value to the input terminals A and B of the comparison circuit 61 is in the relationship A≧B, and the comparison circuit 61 outputs a polished rice cooking completion signal Sh consisting of a high level signal, which is applied to one input terminal of the AND circuit 125. At this time, the other input terminal of the AND circuit 125 is connected to the R-S flip-flop 111.
Since the high level signal from the reset output terminal of the R-S flip-flop 11 is applied,
3 is set. Then, the low level signal from the reset output terminal of the R-S flip-flop 113 is applied to the AND circuit 121, and the AND
Since the output of the circuit 121 is inverted to a low level signal, the duty ratio control circuit 85 is stopped, and
In response to this, the heater drive circuit 84 outputs a gate signal.
The output of Sg is stopped and the triax 14 is kept in a turned-off state, that is, the heater 6 is cut off, thereby completing the rice cooking process for the white rice cooking operation. At this time, a high level signal from the set output terminal Q of the R-S flip-flop 113 is applied to the AND circuits 123 and 124, and the AND circuit 123 allows the pulse signal _P1 to pass through. In response to this, the double cooking control means 143 functions to shift to the uneven cooking process. In short, the temperature of the pot 5 is determined by the temperature value (7th, 8th, 9th temperature value storage unit 32, 33,
34) and the corrected temperature value by the correction means 146 (10th, 11th,
The finished cooking temperature is the sum of any one of the temperature values stored in the 12 temperature value storage units 35, 36, and 37.
When Doff is reached, the rice cooking process is completed and the process moves on to the uneven process, and the operation in this uneven process will be described below. In addition, in the case of this example, the above-mentioned cooking temperature Doff is the seventh
The temperature varies between 114° C. and 122° C. depending on the contents stored in the thirteenth temperature value storage units 32 to 38.

The counter 76 in the double cooking control means 143 is
The pulse signal _P1 is counted from the time the power is turned on, and therefore, at time _t6 , the count value is at least equal to the numerical signal output from the adder circuit 72 (in the case of this embodiment, the pulse signal P1 corresponds to 100 seconds at most). numerical value)
As a result, each input value to the input terminals A and B of the comparator circuit 64 has a relationship of A<B, and the comparator circuit 64 outputs a low level signal. Further, since the other counter 75 in the double-cooking control means 143 starts its counting operation from time _t6 , at that time each numerical value input to the input terminals A and B of the comparator circuit 62 is A.
Since the relationship is ≧B, a high level signal is output from the comparison circuit 62. Then, when the heater 6 is cut off at time t ₆ , the temperature of the pot 5 once overshoots as shown in _FIG . decreases to the double cooking start temperature Dr (103°C) stored in the 14th temperature value storage section 39, each input value to input terminals A and B of the comparator circuit 63 becomes A.
Since the relationship of ≧B is established and a high level signal is output, the trigger circuit 7 that receives the high level signal
9 begins to output a trigger pulse _P3 , and the counter 76 is initialized by the trigger pulse _P3 . Then, the input terminal A of the comparator circuit 64,
Each input value of B has a relationship of A≧B, and a high level signal is output from the comparison circuit 64. In response, high level signals are given to all input terminals of the AND circuit 124, and the AND circuit 124
The output of will be inverted to a high level signal.
As a result, the heater drive circuit 14 receiving the high level signal from the AND circuit 124 turns on the triac 14 to re-energize the heater 6, and in response, double cooking is performed. At this time, the count value of the counter 76 comes to indicate the elapsed time from time _t7 when the temperature of the pot 5 decreased to 103°C, and at time _t8 , the count value corresponds to the output from the adder circuit 72. (i.e., the time obtained by adding the time value corresponding to the amount of cooked rice detected by the rice cooking amount detection means 140 and the corrected time value by the correction means 146 to the reference time N (30 seconds) for double cooking and heating) When reaching A, each input value to input terminals A and B of the comparator circuit 64 becomes A.
<B, and the output of the comparison circuit 64 is inverted to a low level signal, so the AND circuit 12
The output of No. 4 is also reversed, and the heater drive circuit 84 turns off the triac 14, thereby cutting off the power to the heater 6 and stopping the double-cooking heating. After this, at each time T ₉ and t ₁₁ when the temperature of the pot 5 rises once due to double cooking heating and then decreases to 103°C, the heater 6 is energized again in the same manner as described above to perform double cooking heating. At the same time, such double-cooking heating is stopped at each time t ₁₀ and t ₁₂ after the time period in which the count value of the counter 76 corresponds to the output from the adder circuit 72 has elapsed.

Then, at time t13, when the erratic driving time M (15 minutes) stored in the 12th time value storage unit ₅₁ has elapsed after time _t6 , the count value of the counter 75 corresponds to the erratic driving time M. Since the output of the comparator circuit 62 is inverted to a low level signal when the value exceeds the value of The process is then completed. Then, as described above, the comparison circuit 62
When the output of _the inverter 138 is inverted to a low level signal, the output of the inverter 138 is inverted to a high level signal and the trigger pulse _P3 is output from the trigger circuit 80.
The flip-flop 110 is reset, and from this point on, the process proceeds to a warming process using a warming heater (not shown). In summary, in the unevenness process, the temperature of the pot 5 is the temperature for starting double cooking.
When the temperature drops to 103°C, the heater 6 is energized again, and the energization time is 30 seconds, which is the reference time N for double-cooking heating, to the rice cooking amount detection means 140.
The time value (fifth,
any one of the time values stored in the sixth and seventh time value storage sections 44, 45, and 46) and the correction means 1
46 (any one of the time values stored in the 8th, 9th, and 10th time value storage sections 47, 48, and 49) is reached, the heater 6 is turned off. The control of turning on the power to finish cooking twice and heating is repeated, and in the case of this example,
The heating time for the double cooking is 30 seconds to 70 seconds depending on the contents stored in the fifth to eleventh time value storage sections 44 to 50.
changed in seconds.

Up to this point, we have described the effect when the white rice cooking operation is selected, but below we will explain the effect when the porridge cooking operation is selected by turning on the porridge cooking operation selection switch 108, as shown in FIGS. 5 and 6. This will be explained based on the diagram. That is,
After the pot 5 containing rice and the required amount of water is installed in the inner frame 2 and the power is turned on, when the porridge cooking operation selection switch 108 is turned on, the pulse signal P is activated as described above. R-S by ₆
Flip-flop 111 is set. In this state, a low level signal from the reset output terminal of R-S flip-flop 111 is applied to AND circuits 120 and 125. For this reason, AND
AND receiving low level signal from circuit 120
Since the circuit 115 comes to block the passage of the pulse signal P ₁ and the function of the correction means 146 is stopped, the AND circuit 125 comes to block the passage of the polished rice cooking end signal Sh from the comparator circuit 61. , the functions of the double-cooking control means 143 and the first rice-cooking end control means 144 are disabled. Also, at this time, the high level signal from the set output terminal Q of the R-S flip-flop 111 is applied to the transfer gates 101, 103, 105.
are applied to the gate terminals of the transistors, causing them to exhibit a conductive state. Therefore, when the porridge cooking operation is selected, the stored data (70
Temperature detection signals Sd for seconds, 2 minutes 30 seconds, and 3 minutes 30 seconds ago
becomes ready for output.

Thereafter, when the start switch 107 is turned on at time _t0 in FIGS. 5 and 6, the heater output control means 14
2, the heater 6 is energized and the rice cooking process for the porridge cooking operation is started, and the subsequent time
During the period from _t1 to _t2 , the rice cooking amount detection means 140 functions, and one of the transfer gates 86, 87, and 88 becomes conductive depending on the size of the rice cooking amount.

Thereafter, at time _t3 , when the temperature of the pot 5 reaches or exceeds the lower limit temperature "90°C" stored in the third temperature value storage section 28 and a high level signal is output from the comparator circuit 55, the white rice is Similarly to the cooking operation, the boiling detection function of the boiling detection means 141 is enabled. At this time, as described above, the unit registers 83b and 83 of the shift register 83
d, 83f memory data (70 seconds, 2 minutes 30 seconds, 3 minutes
Each temperature detection signal Sd) from 30 seconds ago is in a state where it can be output, and the time indicated by each stored data is stored in the stored data (unit registers 83c, 83e, 83e, 83
It is shorter than the respective times indicated by the respective temperature detection signals Sd) of 2 minutes, 3 minutes, and 4 minutes ago stored in g.
Therefore, a subtraction circuit 68 that calculates the difference between the temperature value indicated by the current temperature detection signal Sd and the temperature value indicated by any of the above-mentioned stored data;
The target temperature gradient indicated by the comparison temperature value (equivalent to 2° C.) stored in the fifth temperature value storage unit 30, that is, the target temperature gradient that serves as a guideline for boiling detection in the boiling detection means 141, is small. It will be reconfigured.

Then, at subsequent time _t4 , when the temperature increase gradient of the pot 5 reaches the target temperature gradient set as described above, the comparison circuit 6 in the boiling detection means 141
7 outputs a boiling detection signal Sz, and the R-S flip-flop 112 is set.
In response, the heater output control means 142 reduces the output of the heater 6 to 300 watts.
Moreover, at this time, the second rice cooking end control means 1
For the input terminal of the AND circuit 126 in 45,
Since a high level signal is given from each set output terminal Q of the R-S flip-flops 111 and 112, the AND circuit 126 is connected to the first frequency dividing circuit 2.
The second rice cooking end control means 14 allows the passage of the pulse signal _P1 with a period of 1 second from
5 functions will be enabled. For this reason,
The counter 77 starts counting the pulse signal _P1 , and the count corresponds to the time elapsed from time _t4 when the output of the heater 6 was decreased. The porridge cooking heating time MD stored in the 13th time value storage unit 52 from the above time t ₄
At time _t5 , when (30 minutes) has elapsed, the comparator circuit 6
The respective inputs of the input terminals A<B of 5 are in the relationship A>B, and the output is inverted to a high level signal.
It is now applied to one input terminal of the AND circuit 128. The other input terminal of this AND circuit 128 is given a high level signal from the set output terminal Q of the R-S flip-flop 111, and therefore, at time _t5 , a high level signal is supplied from the AND circuit 128. Rice porridge cooking end signal
So is output. Then, the trigger pulse _P3 is output from the trigger circuit 80 which receives the porridge cooking end signal So, and the R-S flip-flop 11
Since 0 is reset, the heater output control means 142 turns off the power to the heater 6 in response to this, thereby ending the porridge cooking operation. Also,
When the water stored in the pot 5 is small, etc.
When the evaporation of water in the pot 5 progresses too much and the temperature rises above the heater power-off temperature Dzo (115° C.) for the porridge cooking operation stored in the sixth temperature value storage unit 31, the comparison A high level signal is output from the circuit 66, and a porridge cooking end signal So is output from the AND circuit 128. In this case as well, the porridge cooking operation is stopped to prevent an overheating accident from occurring. become.

Incidentally, when the stop switch 109 is turned on during the above-mentioned white rice cooking operation or porridge cooking operation, the R-S flip-flop 110 is reset by the pulse signal P ₆ output in response to this, so the heater 6 is cut off. and each operation will be stopped.

According to the present embodiment described above, the following effects can be achieved. That is, the boiling detection means 141 does not detect the boiling state of the water in the pot 5 based on a predetermined absolute upper limit temperature as in the conventional case, but detects the boiling state of the water in the pot 5. When the temperature gradient of the pot 5 becomes equal to or lower than a predetermined target temperature gradient (specifically, the amount of change in the temperature of the pot 5 within a predetermined reference time is stored in the fifth temperature value storage section 30). The contact state between the heat-sensitive cap 7 and the bottom of the pot 5 constitutes the temperature detection means 25. Variations in the circuit constants of the thermistor 9 or the A-D converter 24 and changes in their characteristics over time, changes in atmospheric pressure, or changes in the boiling point caused by seasonings being put into the pot 5 when making cooked rice. Even if there are fluctuations, the boiling state of the water in the pot 5 can be accurately detected. In addition, when detecting the boiling state in this way, due to the temperature increase gradient of the pot 5 changing depending on the amount of cooked rice,
When the amount of rice to be cooked differs, there is a risk that the boiling detection as described above may become inaccurate, but in this embodiment, the target temperature gradient at the time of boiling detection is determined depending on the magnitude of the amount of cooked rice detected by the amount of rice to be cooked by the rice amount detection means 140. (specifically, a configuration that changes the reference time required when measuring the temperature gradient).
The boiling state of the water in the pot 5 can always be accurately detected even when the amount of rice to be cooked differs.

In this embodiment, the rice cooking control is performed by causing the heater 6 to generate heat at the rated output until a boiling state is detected, and then reducing the output of the heater 6 by half. Since the boiling state is accurately detected, the rice cooking control described above can be performed strictly even when the amount of rice to be cooked differs in size. Therefore, when cooking white rice, the heater 6 is turned on only until the inside of the pot 5 reaches a boiling state. It is possible to fully satisfy the so-called "medium heat" condition of generating heat at a high output, and it is also possible to cook rice with little burntness, and the rice can be cooked well overall. Also, in both cases of cooking white rice and cooking porridge, the temperature rise gradient of the pot 5 becomes below a predetermined target temperature gradient, that is, the temperature of the pot 5 reaches a predetermined target temperature below the boiling temperature. The output of the heater 6 can be reduced when the boiling state in the pot 5 starts to become intense, and boiling over can be effectively prevented. In particular, when cooking rice porridge, the amount of water in the pot 5 is relatively large, so boiling over is likely to occur due to boiling, but the boiling detection means 141 in this embodiment
When the porridge cooking operation is selected, the target temperature gradient is reset to be larger than that during the white rice cooking operation, so the operation of reducing the output of the heater 6 during the porridge cooking operation is performed earlier than during the white rice cooking operation. It becomes like this. Therefore, an excessive boiling state does not occur, and the effect of preventing boiling over is improved.

In this embodiment, the larger the amount of cooked rice detected by the rice cooking amount detection means 140, in other words, the longer a relatively large amount of unnecessary moisture remains in the pot 5 during dry-up, the more the heater 6 is cut off at the That is, since the rice cooking temperature Doff is raised, the rice can be cooked well from this aspect as well. Moreover, in this case, since the correction means 146 is provided to correct the amount of cooked rice detected by the amount of cooked rice detected by the amount of cooked rice detected by the amount of rice detected by the amount detection means 140 according to the length of the period during which the water in the pot 5 is in a boiling state, the amount of cooked rice is , it is possible to more precisely control rice cooking according to the ratio of rice and water during rice cooking. Furthermore, the double cooking time during the uneven process is also changed to a time corresponding to the amount of cooked rice detected by the rice cooking amount detection means 140 and corrected by the correction means 146.
It is possible to fully alphanize the rice, making the cooked rice even more delicious. Furthermore, in the above embodiment, the temperature of the pot 5 is
The lower limit temperature (90
Since the configuration is such that the function of the boiling detection means 141 is enabled only when the temperature reaches
This eliminates the possibility of erroneously detecting a period when the temperature gradient is flat, such as at the time when the temperature of the pot 5 rises, as a boiling state.

In addition, in the above embodiment, the temperature of the pot 5 ranges from 70°C to 80°C.
Although the rice cooking amount detecting means 140 is configured to detect the rice cooking amount based on the time required for the rice to rise to ℃, the temperature value for detection, that is, the first and second
The stored values of the temperature value storage units 26 and 27 are not limited to these, and may also be used for rice cooking with other configurations, such as one in which the amount of cooked rice is detected by measuring the entire weight of the pot 5. A quantity detection means may also be provided. Of course, each of the other temperature value storage units 28 to 3
9 and the storage contents of each time value storage unit 40 to 52 are also not limited to the above-mentioned embodiments. Furthermore, in the above embodiment, the measurement of the duration of the boiling state by the correction means 146 is performed in the fourth temperature value storage section 29.
However, instead of this, the point at which the temperature of the pot 5 suddenly rises is detected, and the boiling duration is measured based on the detection result. You can also do it. Further, in the above embodiment, the rice cooking amount detected by the rice cooking amount detecting means 140 is ranked in three levels, but this may be further ranked in multiple levels. 14
1 and the configuration of the correction means 146 are also changed accordingly, but by configuring them in this way, boiling detection can be performed more precisely. In the above embodiment, the electric power during double-cooking heating is changed by time control, but other configurations may be used as long as the average electric power of the heater 6 is changed.
Further, the energization time of the heater 6 during double-cooking heating does not need to be constant each time as in the above-mentioned embodiments, and may be made to become shorter sequentially during each double-cooking heating, for example. In addition,
In place of the duty ratio control circuit 85, a circuit configured to reduce the output of the heater 6 using a phase control method may be adopted, and in place of the triax 14, another switching element such as a relay may be used. good.

In addition, the present invention is not limited to the embodiments described above and shown in the drawings; for example, each functional part shown in hardware in FIG. 1 may be replaced by a microcomputer program. , it is possible to implement various modifications without departing from the gist thereof.

[Effects of the Invention] According to the present invention, as is clear from the above description, when performing rice cooking control such as cooking white rice or cooking porridge, the temperature detected by the heat-sensitive element is lower than the boiling temperature after the heating means starts to be energized. Since the heating output is reduced when the predetermined target temperature is reached, it is possible to effectively prevent boiling over from inside the pot, and the amount of water is large compared to the amount of rice. When cooking rice porridge, which tends to boil over, the heating output is reduced earlier than when cooking white rice, which further increases the effect of preventing rice from boiling over. During execution, the target temperature is changed so that the larger the amount of rice to be cooked, the higher the target temperature. This has the excellent effect of ensuring that the rice is always well-cooked.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a block diagram of the electrical configuration, Fig. 2 is a partially cutaway side view of the rice cooker, and Fig. 3 shows a rice cooker when the rice cooking operation is selected. Fig. 4 is a timing chart showing the output waveforms of each part in Fig. 1 in the same state, Fig. 5 is a pot with the porridge cooking operation selected. FIG. 6 is a timing chart showing the output waveforms of various parts in FIG. 1 under the same conditions. In the figure, 1 is the rice cooker body, 5 is a pot, 6 is a heater (heating means), 7 is a heat-sensitive cap, 9 is a thermistor (heat-sensitive element), 10 is a pot switch, 13 is a control circuit, 25 is a temperature detection means, 77 is a counter, 84
85 is a heater drive circuit, 85 is a duty ratio control circuit, 107 is a start switch, 108 is a porridge cooking operation selection switch, 109 is a stop switch, 139 is a clock means, 140 is a rice cooking amount detection means, 141 is a boiling detection means, and 142 is a heater output. 143 is a double-cooking control means, 144 is a first rice-cooking end control means, 145 is a second rice-cooking end control means, and 146 is a correction means.

Claims (1)

[Claims] 1. An electric appliance that is equipped with a pot that stores rice and water, a heating means that heats the pot, and a heat-sensitive element that detects the boiling state of the pot, and that can selectively perform rice porridge cooking and white rice cooking courses. In the rice cooker,
The heating output is configured to be reduced when the detected temperature of the heat-sensitive element reaches a predetermined target temperature below the boiling temperature after the start of electricity supply to the heating means, and when the rice porridge cooking course is executed, the target temperature is reduced. heating of an electric rice cooker, characterized in that the target temperature is changed to be lower than when executing a rice cooking course for cooking white rice, and the target temperature is changed to be higher when the amount of rice cooked is larger when executing a rice cooking course for cooking white rice. Control method.