JPH0342892B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an electronic rice cooker in which the rice cooking switch part is electronic.

(b) Conventional technology The rice cooker switch part of a rice cooker has traditionally been a mechanical lever type using a magnet, as shown in Japanese Patent Application Laid-Open No. 55-54923, but the structure is complex and wide. Since storage space is required, in recent years, electronic types using a microcomputer and a temperature sensing element such as a thermistor have been adopted.

By the way, in the rice cooker that uses a microcomputer, a rice cooker switch that does not have a mechanical hold, such as a push button switch, is used, so if a power outage occurs while the rice is being cooked or kept warm, when the power is restored, the rice cooking switch will be turned off. A problem arises in that it is not possible to determine whether the rice is hot or not while it is being kept warm, making it impossible to continue cooking or keeping the rice warm. In addition, unlike mechanical rice cookers, the rice cooking switch cannot be manually released, so if rice cooking is started due to an erroneous operation, the power supply must be stopped by unplugging the power plug, etc. to stop rice cooking. However, when the power is turned off, not only the rice cooking circuit but also the power supply to other circuits is stopped.
There also arises a problem that the display becomes inconvenient, such as the display becoming invisible.

(c) Problems to be solved by the invention The present invention has been made in consideration of the above points.
Even if a power outage occurs while cooking rice or keeping it warm, it can automatically return to the original rice cooking circuit or warming circuit when the power outage returns, and even if rice cooking starts due to an erroneous operation, it can be canceled without turning off the power. It provides an electronic rice cooker.

(d) Means for Solving the Problems The present invention provides a rice cooking circuit, a warming circuit, a storage means for storing different signals during the rice cooking operation and during the warming operation, and a determination means for discriminating the signals of the storage means. and,
The apparatus includes a control means for returning to the original rice cooking circuit or heat retention circuit based on the output of the determination means after a power outage, and a manually operated rice cooking cancel switch, and the control means is configured to operate the rice cooking cancel switch when the rice cooking cancel switch is operated during the rice cooking operation. When the rice cooking circuit is turned off, the rice cooking circuit is released.

(E) Function Since the present invention is configured as described above, the storage means stores a signal indicating rice cooking during the rice cooking operation and a signal indicating keeping warm during the warming operation, and when a power outage occurs, the memory is stored. Content is preserved. When the power outage returns, it is determined whether the rice was being cooked or kept warm before the power outage based on the signal stored in the storage means, and the original rice cooking circuit or warming circuit is restored based on the determination result. Furthermore, if the rice cooking cancel switch is operated during the rice cooking operation which has been started due to an erroneous operation, the rice cooking circuit is released and the rice cooking operation can be canceled at will.

(F) Embodiment Hereinafter, an embodiment of the present invention will be explained with reference to the drawings. Reference numeral 1 denotes a lid heater disposed inside the lid body, which is connected in series to a power source 2, and is constantly activated when power is supplied. It generates heat. 3 is a rice cooking heater, which is connected to the power supply 2 together with the rice cooking triax 4.
are connected in series to form a so-called rice cooking circuit 5. Reference numeral 6 denotes a heat-retaining heater connected in parallel to the rice-cooking triax 4;
A so-called heat-retaining circuit 8 is formed by connecting the heat-retaining triac 7 in series. 9 is a DC power supply circuit for a microcomputer, which will be described later. Reference numeral 10 denotes a temperature sensing element such as a thermistor that senses the completion temperature of rice cooking or the temperature at which the rice is kept warm. Reference numeral 11 denotes a temperature detection circuit that detects the temperature of the temperature sensing element 10 and outputs it to a microcomputer to be described later. Reference numeral 12 denotes a microcomputer (control means) that controls the rice cooking triac 4, the warming triac 7, etc. in accordance with the input from the temperature detection circuit 11 or a comparison circuit to be described later. Reference numeral 13 denotes a comparison circuit (judgment means) formed by a comparator or the like, which inputs the comparatively detected potential to the microcomputer 12, and controls the rice cooking triax 4 or the warming triac 7 according to the input potential. , which supplies the power source 2 to the rice cooking circuit 5 or the heat retention circuit 8. The comparison circuit 13
The side thereof is connected to the midpoint between the resistors R1 and R2, and the side thereof is connected between the cathode of the thyristor 14 and the capacitor 15 via the resistor R3. The capacitor 15 forms a charging circuit (memory means) 16, and is connected to the transistor Q via a resistor R4. A resistor R5, a diode D, and a resistor R6 are connected between the anode of the thyristor 14 and the rice cooking switch 17.

Reference numeral 18 denotes a manually operated rice cooking cancel switch connected in parallel with the transistor Q, forming a discharge circuit for the capacitor 15 via a resistor R4.

Then, when the signal potential at point B of the capacitor 15 becomes higher than the signal potential at point A divided by the resistors R1 and R2, the output of the comparator circuit 13 is set to a "high level" indicating rice cooking operation. The microcomputer 12 is set to detect this "high level" and turn on the rice cooking triator 4. Further, when the signal potential at point B becomes lower than the signal potential at point A, the comparison circuit 1
3 is set to a "low level" indicating a heat-retaining operation, and the microcomputer 12 detects this "low level" and activates the heat-retaining triac 7.
Set it to ON.

To explain the operation of this configuration, the rice cooking operation is started by turning on the rice cooking switch 17. That is, the gate signal is input to the thyristor 14, which turns on, and the capacitor 15 of the charging circuit 16 is immediately charged, and the signal potential at point B becomes higher than the signal potential at point A.
The rice cooking operation will be memorized. The comparison circuit 13 detects this and inputs this result to the microcomputer 12.
A rice cooking circuit 5 is formed by making the rice cooking triax 4 conductive at the output of 2 to energize the rice cooking heater 3. Until the temperature sensing element 10 detects the rice cooking completion temperature, the temperature change of the pot housing the rice to be cooked takes the form of a curve as shown in the X region in FIG. Then, the rice cooking completion temperature is determined by the temperature sensing element 1.
When 0 is detected, this information is input to the microcomputer 12 through the temperature detection circuit 11, and the rice cooking triac 4 is made non-conductive and the warming triac 7 is made conductive, thereby forming a warming circuit 8. At the same time, the microcomputer 12 turns on the transistor Q to discharge the capacitor 15, and makes the signal potential at point B lower than the signal potential at point A to memorize the warming operation. The heat-retaining operation is carried out by detecting the optimal temperature for heat-retaining the temperature sensing element 10 and controlling the heat-retaining triac 7 on and off through the microcomputer 12. After the temperature sensing element 10 detects the rice cooking completion temperature,
The temperature change in the pot takes the form of a curve like the Y area in FIG.

However, with conventional methods, when the power supply is temporarily stopped due to a power outage or by unplugging the power plug while cooking rice or keeping it warm, and when it is restored again,
As is clear from Fig. 2, since there are two points at the same temperature, point H and point L, the temperature detected by the thermosensor 10 after recovery may indicate whether the rice was being cooked before the power supply was stopped, or whether it was being kept warm. For example, the rice may stop at point H, and when restarting, it starts from point L and does not complete the cooking operation, or the rice cooker may not be able to complete the cooking operation when the rice is kept warm.
Even though it stopped at point H, after returning, it started working from point H and cooked rice twice. However, according to the present invention, even if there is a power outage at point H during rice cooking, the charging circuit 16 maintains the high potential at point B indicating that the rice cooking operation is in progress because the rice is still being cooked, and after the power is restored, the high potential at point B is maintained. Microcomputer 1
2, the rice cooking triax 4 is made conductive, and the rice cooking circuit 5 is surely returned to the original rice cooking circuit 5. Also, keep warm L
Even if there is a power outage at the
The capacitor 15 is discharged and the point B maintains a low potential indicating that the temperature is being kept warm, and after the power is restored, the point B
The low potential at the point is detected by the microcomputer 12, the heat-retaining triac 7 is made conductive, and the original heat-retaining circuit 8 is reliably restored.

The rice cooking cancel switch 18 is used to cancel the rice cooking operation when the user accidentally turns on the rice cooking switch 17 and starts the rice cooking operation. That is, when point B of the capacitor 15 maintains a high potential,
Short-circuit both ends of transistor Q and connect capacitor 1
5 to maintain the potential at point B at a low potential. As a result, the comparator circuit 13 changes from "high level" to "low level", which is detected by the microcomputer 12 to form the heat retention circuit 8. That is, the rice-cooking triax 4 is made non-conductive to release the rice-cooking circuit 5, and the heat-retaining triax 7 is made conductive to form the heat-retaining circuit 8. Therefore,
When canceling the rice cooking operation as necessary, only the rice cooking circuit 5 is canceled by operating the rice cooking cancel switch 18, so there is no need to stop the entire power supply.

(g) Effects of the invention Since the present invention is constructed as described above,
When the power supply is temporarily stopped due to a power outage while cooking or keeping the rice warm, and when the power is supplied again, the rice cooking circuit or warming circuit returns to the original one, even though the rice cooking has not finished completely like in the past. This eliminates the situation of shifting to the warming operation or repeating the rice cooking operation twice. At this time, different signals are stored in the storage device for cooking and keeping rice warm, so when the power is restored, the state before the power outage can be accurately and quickly determined without having to make judgments based on pot temperature, slope, etc. .

In addition, a manual switch is provided to cancel the rice cooking circuit during the rice cooking operation, so the rice cooking operation can be stopped without stopping the entire power supply and malfunctions of the rice cooking switch can be canceled at will, improving operability. do.

[Brief explanation of drawings]

FIG. 1 is an electric circuit diagram showing an embodiment of the present invention;
FIG. 2 is a curve diagram showing the temperature change of the pot of the same example. 5...Rice cooking circuit, 8...Warming circuit, 16...Charging circuit (memory means), 13...Comparison circuit (determination means), 12...Microcomputer (control means), 18...Rice cooking cancellation switch.

Claims (1)

[Claims] 1. A rice cooking circuit, a warming circuit, a storage means for storing different signals during the rice cooking operation and during the warming operation, a determination means for determining the signal of the storage means, and a heating circuit based on the output of the determination means after a power outage. the rice cooking circuit or the warming circuit; and a manually operated rice cooking cancel switch, and the control means cancels the rice cooking circuit when the rice cooking cancel switch is operated during the rice cooking operation. Electronic rice cooker.