JPS6021718A - Rice cooker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a rice cooker that determines the rice cooking capacity and then adjusts the heating power, thereby making it possible to obtain rice with less uneven cooking regardless of the rice cooking capacity. be.

(Prior art) Recently, this type of rice cooker has a preheating process, a capacity determination process in which rice cooking capacity determination data is collected and the rice cooking capacity is determined based on the data, and a rice cooker that cooks rice using a heating power according to the determination result in the previous process. Various rice cookers have been developed that sequentially perform the cooking process.

In such rice cookers, the preheating process is aimed exclusively at promoting water absorption of rice, and various heating sequences have been considered for this preheating process, but in any of them, the initial water temperature The amount of water absorbed by rice changes greatly depending on the ambient temperature, etc., and this adversely affects the determination of rice cooking capacity, resulting in not only inaccurate rice cooking capacity but also rice that is cooked unevenly. For example, the temperature of the cooked food is increased from the start of cooking to the starting temperature of the capacity determination process using low heat, and the time during which the rice is immersed in water is increased to promote water absorption of the rice. However, with this method, the soaking time varied greatly depending on the initial water temperature, ambient temperature, etc., which caused a large change in the amount of water absorbed by the rice.

(Purpose) The present invention has been made in view of the above-mentioned points, and is capable of heating the food to a certain temperature at once from the start of rice cooking at the maximum output of the heater by continuously supplying electricity to the heater, and then heating the food to a certain constant temperature for a predetermined period of time. By gradually heating the rice to the starting temperature of the capacity determination process, the rice absorbs sufficient water, and at the same time suppresses fluctuations in water absorption due to initial water temperature, ambient temperature, etc., making it possible to accurately determine the rice cooking capacity. This makes it possible to cook rice with less uneven cooking.

(Example) Examples of the present invention shown in the drawings will be described in detail below.

First, in Figure 1, which shows the schematic structure of the rice cooker of the present invention, 1 is the main body of the jar rice cooker, 2 is the outer pot, and 3 is the outer pot 2.
4 is a hot plate type rice cooking heater installed on the inner bottom of the outer pot 2; 4 is an inner pot that can be moved in and out of the outer pot 2 to store food to be cooked; 5 is a heat-retaining heater provided on the outer surface of the outer pot 2; 6 is a heater of the inner pot 4; A thermosensor such as a thermistor that is in contact with the center of the outer bottom surface and detects changes in the temperature of the food being cooked; 7 is a thermal reed switch that is located on the outer surface of the outer pot 2 and is used to keep the food warm; 8 is a thermal reed switch that detects changes in the temperature of the food being cooked; 8 is the main body 1;
An operation panel 9 is provided on the outer surface of the operation panel 8, and a control board 9 is installed inside the operation panel 8. Although not shown in the drawings, it goes without saying that an inner lid for opening and closing the opening of the inner pot 4 and an outer lid for covering the outside of the inner pot 4 are provided as is well known in the art.

The operation panel 8 has a time display section lO as shown in the second figure.
It also has an operation status display section 11 for warming, double cooking, uneven cooking, preheating, rice cooking, etc., as well as a timer set key 12 and various control keys 13.

Next, FIG. 3 is a circuit diagram in which the present invention is implemented by a microcomputer, in which the rice cooking heater 3 is connected to the AC power supply 15 through the contacts of the rice cooking relay 14, and the rice cooking relay 1
A series circuit consisting of contacts of a heat-retaining heater 5, a heat-retaining thermal reed switch 7, and a heat-retaining relay 16 is connected to the contact point 4 in parallel.

Therefore, the above-mentioned rice cooking relay 14 and heat retention relay]6 are ON and OFF controlled by the microcomputer described later,
By controlling the electricity supply to the rice cooking heater 8 and the warming heater 5, rice cooking or warming operation is executed. Also, both relays 14. ] 6 is provided on a control board 9, and this board 9 is also provided with a microcomputer, a time display element, a light emitting diode, a switch, etc., and the time display element, light emitting diode, and switch are connected to each display on the operation panel 8. 10.11 and various keys 12.13 are made to correspond to predetermined relationships. The power for the control section as described above is obtained from an AC power source via a transformer 17.

FIG. 4 is a block diagram of the entire control circuit. In FIG. 4, an 18t/'i microcomputer mainly includes a central processing unit (hereinafter referred to as CPU) 19, an electronic timer 20, and a read-only memory (hereinafter referred to as ROM) 2.
1, an arbitrary access memory (hereinafter referred to as RAM) 22 and an interface (input/output signal processing circuit) 23. The ROM 21 stores the control program for the CPU 19, and the RAM 22 stores the control program for the CPU 19.
The CPU 19 reads the status of each part on the input side via the interface 23', and also reads the status of each part on the input side.
By reading out the control program, processes such as preheating, capacity determination, boiling, double-cooking, uneven cooking, and keeping warm are determined, and the heating units necessary to execute the processes are controlled via the interface 23. The process transition is carried out by the electronic timer 20 in cooperation with the CPU 19.The electronic timer 20 counts a predetermined time according to instructions from the CPU 19 and outputs a signal after the predetermined time.

In the above configuration, the control will be explained in detail below.

First, FIG. 5 is a main flowchart of the rice cooker of the present invention, in which the steps of primary heating, secondary preheating, capacity determination, cooking, double cooking/uniformity, and heat retention are sequentially executed from the start of rice cooking. Each process other than the cooking process and the warming process is executed for a predetermined period of time. Also, the cooking process ends by detecting the temperature of the food being cooked.
It becomes approximately constant by adopting a control method that will be described in detail later. In addition, FIG. 6 is a curve diagram showing the relationship between the elapsed time from the start of rice cooking to keeping it warm and the temperature change of the thermosensor. Control of each process will be explained below.

〇 - Next, turn on the control key 13 for secondary preheating process rice cooking/timer start.
By storing this in the storage means A in the CPU 19 and reading out the control program contents in the ROM 21 corresponding to the stored contents, the flowchart of the primary heat process shown in FIG. 7 and subsequently shown in FIG. Control as shown in the flowchart of the secondary preheating process.

In the primary heating process, when the rice cooking/timer start control key 13 is turned on, the set temperature of the thermosensor 6 is set to a predetermined temperature slightly higher than room temperature, and the contact of the rice cooking relay 14 is turned on to turn on the rice cooking heater 3. energization is started, and the food to be cooked is preheated for a certain period of time T1. The temperature setting of the thermosensor 6 and the determination as to whether the set temperature has been reached are performed as follows. The temperature detected by the thermosensor 6 is converted into a digital signal by digital-to-analog conversion and is read into the CPU 19, where the digital signal is compared with the set temperature stored in the ROM 21 to determine if it matches. A mismatch is determined.

The rice cooking heater 3 is continuously energized until the temperature of the thermosensor 6 that detects the temperature of the food reaches a predetermined temperature t1, and the rice is heated at its maximum output. however,
If the temperature of the thermosensor 6 does not reach the predetermined temperature even after the waiting time T has elapsed, the process moves to the next stage of the secondary preheating process after 13 hours have elapsed. - Conversely, if the temperature of the thermosensor 6 reaches the predetermined temperature t1 within 11 hours, the remaining time is set to ON-MAX for 10 seconds (for example, 15 seconds) and OFF for several seconds (for example, 5 seconds).
By switching to the intermittent control of -Fix, control is performed to maintain the predetermined temperature t1 as much as possible. This intermittent control will be explained. Now, if the temperature of the thermosensor 6 reaches the predetermined temperature t1 due to continuous energization to the rice cooking heater 3 and the energization to the rice cooking heater 3 is stopped, the temperature determination means B in the CPU 19 will stop the energization to the rice cooking heater 3. When 5 seconds have passed, it is determined whether the temperature of the thermosensor 6 is higher than the predetermined temperature t1, and if it is, the power supply to the rice cooking heater 3 is continued to be stopped, and after another 5 seconds, the thermosensor 6 is turned on again.
The temperature is determined. Conversely, if the temperature of the thermosensor 6 is lower than the predetermined temperature t1, the power supply to the rice cooking heater 3 is restarted, and when the temperature of the thermosensor 6 reaches the predetermined temperature t1, the power supply to the rice cooking heater 3 is stopped again. , the temperature of the thermosensor 6 is determined again after 5 seconds have elapsed since the energization was stopped. Even if the rice cooking heater 3 is continuously energized for 15 seconds, if the temperature of the thermosensor 6 does not reach the predetermined temperature t1, the energization to the rice cooking heater 3 is stopped after 15 seconds have elapsed, and the thermostat is turned on again after 5 seconds have elapsed. The temperature of the sensor 6 is determined, and if necessary, the rice cooking heater 3 is energized.

As described above, when the temperature of the thermosensor 6 reaches the predetermined temperature t1 within T1 time, 15 sheets N-MAX,
It performs intermittent control of 0FF-Fix for 5 seconds, and an example of the control state is shown in Fig. 9.The above-mentioned time of 15 seconds or 5 seconds is not particularly limited, and may vary depending on the size of the rice cooker. This is a time that can be determined at any time depending on the size and structure of the rice-cooking heater. Therefore, the purpose of this -tsujiko heating process is to correct the temperature of the food to be cooked relative to the water temperature and air temperature at the beginning of rice cooking. This is to enable the temperature rise of the food to be cooked to keep up with the control mode described later even when the water temperature at the start of rice cooking is low or the air temperature is low.

The reason why the intermittent control of 15 seconds ON-MAX and 5 seconds 0FF-Fix was adopted will be explained in detail in the next stage of the secondary preheating process.

In the secondary preheating step, the temperature of the food that has been raised to a predetermined temperature t1 in the second heating step is further increased to temperature t2 over a certain period of time T2. ON-MAX, '5 seconds OI'F-F
While executing the intermittent control method of ix, the set temperature of the thermosensor 6 is increased by, for example, 2° C. every time a certain period of time, for example, 52 seconds has elapsed.

Now that the -second heating process is finished and the second preheating process begins, set the temperature of the thermosensor 6 to (t, +2°C) and set the temperature interval time T3 to 52 seconds. , 15 seconds ON-MAX, 5 seconds 0FF-Fix, which controls the power supply to the rice cooking heater 3 to start secondary preheating of the food. Then, every time 52 seconds elapse, the set temperature of the thermosensor 6 is increased by 2°C, and eventually, after a certain period of time T2 has elapsed from the start of secondary preheating, the set temperature of the thermosensor 6 reaches the t2 temperature. Once the flag area C of the RAM 22 is designated, the process moves to the next capacity determination process.

Such a secondary preheating process promotes water absorption of rice,
The purpose is to make the temperature of the cooked food constant and uniform when proceeding to the next stage of capacity determination step, regardless of the rice cooking capacity, so that the capacity can be determined accurately. Therefore, it is desirable to set the t2 temperature to about 60°C, and it is desirable to set the T2 time to about 8 to 10 minutes.

Here, the reason for adopting the intermittent control method of 15 seconds ON-MAX and 5 seconds 0FF-Fix will be described.

In the case where the set temperature of the thermosensor 6 is gradually increased as in the present invention, if the rice cooking heater 3 is continuously energized for too long, the temperature of the thermosensor after stopping the energization to the rice cooking heater 3 may change. Open NEET is the 1st O
As shown in Figure 10(b), the overshoot becomes too harsh and ideal control is no longer possible, but by adopting an intermittent control method, overshoot can be suppressed to a small level as shown in Figure 10(b), resulting in ideal control. becomes possible. Furthermore, the temperature difference between the top and bottom of the food to be cooked, especially the water, can be greatly reduced, if not eliminated, compared to continuous energization.

The preheating control means for executing the primary and secondary preheating steps as described above is the rice cooking/timer start control key +3.
．． It is composed of a storage means A in the CPU 19, temperature determination means B5, control program contents in a ROM 2 corresponding to the storage contents of the storage means A, a thermosensor 6, a rice cooking relay 14, and the like.

- Capacity judgment process When moving from the secondary preheating process to the capacity judgment process, RAM2
Based on the designation of the flag area C of No. 2, the first
Control is performed as shown in the flowchart shown in FIG.

In this capacity determination step, the temperature of the food that has risen to temperature t2 is raised to temperature t8 over a certain period of time T.During this time, the temperature of the cooked food, which has risen to temperature t2, is increased to temperature t8. 5 seconds 0FF-Fi
In addition to executing the intermittent control method of x (, thermo sensor 6
As shown in Figure 12, the set temperature is increased by, for example, 2°C every time a certain period of time, for example 40 seconds, elapses, and the energization time to the rice cooking heater 3 during this period is stored in the rice cooking capacity determination data storage area in the RAM 22. Let's integrate the line (
.

Now, proceeding to the capacity determination step, the set temperature of the thermosensor 6 is set to (t2 + 2°C), the temperature interval time T5 is set to 40 seconds, ON-MAX is set for 15 seconds,
Execute the intermittent control method of 0FF-'Fix for 5 seconds. During this time, if the temperature of the thermosensor 6 is lower than the set temperature, the rice cooking heater 3 is energized for a maximum of 15 seconds to heat and raise the temperature of the food, while adding up the energization time to the rice cooking heater 3. go.

In this way, every time 40 seconds elapse, the set temperature of the thermosensor 6 is increased by 2 degrees Celsius, and the energization time to the rice cooking heater 3 is accumulated, and eventually 14 hours have passed since the start of the capacity determination process. When the set temperature of the thermosensor 6 reaches the t3 temperature and the flag area of the RAM 22 is specified, the rice cooking capacity is determined based on the cumulative energization time of the rice cooking heater 3.

Incidentally, in the capacity determination step, the timing of energizing the rice cooking heater with respect to changes in setting and measured temperature is illustrated in FIG. 13.

In the capacity determination step, the t3 temperature is not particularly limited, but is preferably determined within the range of 85°C to 90°C. That is, in the structure of the rice cooker as shown in the first diagram, from t2 (around 60°C) to t3 (85 to 90°C)
The temperature range is the temperature range where the rice cooking heater energization time changes the most depending on the size of the rice cooking capacity, and is the most preferable period for collecting the rice cooking capacity determination data.

Next, determination of rice cooking capacity will be explained. The rice cooking capacity is determined by reading out the rice cooking capacity determination program previously stored in the ROM 21 based on the designation of the flag area, and determining the rice cooking capacity as shown in the flowchart shown in FIG. Determine the heating sequence during the cooking process. This heating sequence is a heating power adjustment, specifically a fixed period (for example, 64 seconds)
A so-called duty control method is used to adjust the time during which electricity is applied to the rice cooking heater 3. The heating chutes for the next stage of cooking process determined as a result of capacity determination are as follows:
Apply a heater voltage appropriate to the rice cooking capacity, but in order to completely gelatinize the rice, make sure the rice is kept at 90℃ or above for 20 minutes or more, avoid boiling, and adjust the cooking time. It is decided that it should be kept constant.

In addition, the rice cooking capacity is determined by taking into consideration the accumulated time of energizing the rice heater, the power supply voltage when the rice heater is energized, and whether the rice is cooked by a timer or by instant cooking, thereby making the determination more accurate. That is, as can be seen from the experimental data shown in FIG. 15, even when the cumulative rice cooking heater energization time is the same, the rice cooking capacity determination result varies greatly depending on the level of the power supply voltage and whether or not timer rice cooking is used. For example, when the cumulative time is 240 seconds, the rice cooking capacity determination value varies over a range of 3 to 8 cups.

For this reason, it is possible to perform accurate capacity determination by performing program processing based on the above three conditions, and the mechanism is shown in the flowchart of FIG. 14. The above-mentioned timer rice cooking will be explained in detail in a later section, but in the case of timer rice cooking, the rice is immersed in water from the time the time is set until the rice cooking starts, and it has absorbed some water when the rice cooking starts. Compared to instant-cooked rice, the amount of water absorbed by rice is different, and this causes a difference in the cumulative energization time of the rice-cooking heater even if the rice-cooking capacity is the same.As a result, when determining the rice-cooking capacity, whether it is timer-cooked rice or instant-cooked rice is included as a condition. By doing this, the amount of water absorbed by rice is corrected.

In FIG. 14, the rice cooking capacity is determined at the end of the capacity determination process. First, by continuing the timer rice cooking determination contents temporarily stored in the RAM 22, it is determined whether the rice cooking currently being executed is timer rice cooking or instant rice cooking. still,
The time setting means E reads whether or not the time has been set using the timer set key before operating the rice cooking/timer start key, and temporarily stores the information in the RAM 22 in advance. After this determination is completed, the value of the current power supply voltage is compared with the value stored in ROM2+,
It is determined which of three regions the power supply voltage falls into, low voltage, standard voltage, and high voltage, and then the rice cooking capacity is determined as shown in the flowchart of FIG. 16 based on the cumulative energization time of the rice cooking heater. The rice cooking capacity is divided into 16-p categories depending on timer rice cooking and instant rice cooking, and the state of the power supply voltage for each rice cooking, and each category is further divided into 10 stages according to the specific time width of the rice cooking heater energization time. A heating duty is set for each capacity as described below, and the contents of these programs are stored in advance in the ROM 21.

After determining the power supply voltage, the rice cooking heater energization cumulative time TR temporarily stored in the RAM 22 is read out, and
By reading the rice cooking capacity determination program in the ROM 21, the rice cooking capacity is determined as shown in the flowchart shown in FIG.
The rice cooking capacity when the relationship becomes 0 is determined, and the heating duty is determined based on this determined capacity Go. When the flag area F of the RAM 22 is designated after 14 hours have elapsed in this way, the process moves to the next cooking process.

As described above, in the capacity determination process, the set temperature of the thermosensor 6 is increased by 2 degrees Celsius every 15 hours, and the temperature is turned on for 15 seconds.
By executing the intermittent control method of MAX, 5 seconds 0FF-Fix, the temperature of the food to be cooked is raised from t2 temperature to t3 temperature over 14 hours, the time during which electricity is applied to the rice cooking heater 3 is accumulated, and this Based on the cumulative energization time, the rice cooking capacity is determined in consideration of the state of the power supply voltage and whether the rice is cooked on a timer or immediately, and the heating duty in the cooking process is determined.

As can be seen from Figure 14, the number of determinations for rice cooking capacity is 60 types in 6 categories and 10 stages, all with different heating duties, and these heating duties are as follows:
■It is based on the formula.

The above formula 0 is a formula for calculating the heating power until boiling, and the formula (2) is a formula for calculating the heating power after boiling. Here, by keeping the cooking time (■10■) constant, the heating power (■+
■) can be determined from formula 00. Then, a heater of a size that has a margin for the maximum value of the heating power (■ + [F]) determined in this way is adopted as a rice cooking heater, and by controlling the duty of this heater, it is suitable for each capacity. generates additional heating power.

In the D-f utility control, the time T6 for energizing the rice cooking heater 3 within a certain period is determined by the following two equations (see Fig. 17).

Incidentally, the cycle of the Tutee control is set to 64 seconds, but this is a value set in consideration of the lifespan of the rice cooking relay 14, and is not particularly limited to this number.

0 Cooking process When moving to the cooking process, the heating program contents corresponding to the heating duty determined in the previous capacity determination process are stored in the ROM2 based on the designation in the flag area F of the RAM22.
By reading 1, the rice cooking heater 3 is duty-controlled and the temperature of the food is raised to the cooking temperature t4 (approximately 124℃), and when the temperature exceeds t4, the thermosensor 6, the process is finished, and the flag area G of the RAM 22 is designated to proceed to the next double-cooking/smoothing process (see the flowchart in Fig. 18). Unlike each process, the process ends when the temperature of the thermosensor 6 reaches the t4 temperature, so it includes an element of temporal instability. By determining the heating duty and controlling the duty of the rice-cooking heater based on this in the process, the time T7 required for the rice-cooking process has extremely small fluctuations and remains approximately constant 〇〇 Twice Cooking and unevenness process In the double cooking and unevenness process, the browning setting contents temporarily stored in the RAM 22 are read based on the designation of the flag area G of the RAM 22, and the control program contents in the ROM 21 corresponding to the setting contents are read out. By reading out, the control is performed as shown in the flowchart shown in FIG. 19, and after a certain period of time T8 (for example, 12 minutes), the flag area H of the KRAM 22 is designated and the process is moved to the warming process.

First, to adjust or set the moss, press the control key 13 for controlling the moss to select "Standard" → "Light" → "Standard" →
It can be set repeatedly in the order of "Dark" → "Standard" → "Light" →..., and the burnt degree determining means I counts the number of times the control key 13 is pressed, and determines the number of times the control key 13 is pressed. ) is temporarily stored in the RAM 22. Then, when transitioning to the double-cooking/unevening process, the burn setting contents are read out from the RAM 22, and the control program contents in the ROM 21 corresponding to these contents are read out, as shown in the flowchart shown in FIG. 19. Control. In addition, each figure in FIG. 20 is a diagram showing the relationship between the temperature change of the thermosensor and the energization state of the rice cooking heater in the same process, and (a) t
/irLight" setting, (b) shows the "Standard" setting, and (c) shows the "Dark" setting.

If it is currently set to "Light", it will detect that the temperature of the thermosensor 6 has become less than the t4 temperature (124℃) and start counting the time, and when one minute has passed, the rice cooker heater 3 will be activated for a short time. Electricity is applied (for 5 seconds) to burn the food, that is, rice, and then electricity to the rice cooking heater 3 is stopped.

When set to "Standard", it detects that the temperature of the thermosensor 6 has become less than the t4 temperature and starts counting the time, and when one minute has passed, the rice cooking heater 3 is energized and the temperature of the thermosensor 6 is increased. The food to be cooked is heated until the temperature reaches t4, and when the temperature reaches t4, electricity to the rice cooking heater 3 is stopped and the rice cooking heater 3 is kept in a stopped state thereafter.

When set to "Dark", the above "Standard" and jll[
After the temperature of thermosensor 6 becomes less than t4 temperature;
After one minute, the rice cooker heater 3 is energized to raise the temperature to t4 again.After that, the temperature of the thermosensor 6 is counted for 1 minute from the time when it becomes less than the t4 temperature, and 1 minute is reached. After the elapsed time, the rice cooking heater 3 is energized and now -
The food to be cooked is heated until the temperature of the group thermosensor 6 reaches the t4 temperature, and then the electricity supply is stopped.

Thus, the double-cooking and steaming process ends when 18 hours have elapsed from the start, and the flag area H of the RAM 22 is designated and the process moves to the warming process.

This double-cooking/smoothing process finishes the rice by draining the cooked rice and adjusting the browning level. You can get food.

Incidentally, the burn setting can be made arbitrarily before proceeding to the double-cooking/unshading process, and subsequent setting operations will be invalid.

As described above, the rice cooking control means includes the preheating control means, each flag area of the RAM 22, the program contents in the ROM 21 corresponding to each area, the electronic timer 20. ROM21 and RA
It includes other memory contents in M22, and starts cooking rice by determining the capacity of the food to be cooked based on the signal from the thermosensor 6 and controlling the power supply to the rice cooking heater 3 based on the determination result ( - The rice cooking device is configured to complete the rice cooking in a substantially constant cooking time from the start of second rice heating, and to finish the rice after a certain uneven time after the rice cooking is completed.

- Heat retention process When the heat retention process is entered, the heat retention relay I6 is turned on, and this ON state continues until the cancel control key 13 is pressed. The heat retention process is controlled by a heat retention thermal reed switch 7 that detects changes in the temperature of the food, and as shown in FIG. 21, the thermal reed switch 7 is turned on.

When turned off, the power supply to the rice cooking heater 3 and the warming heater 5 is controlled to keep the rice to be cooked warm.

The temperature setting of the thermal reed switch 7 is set to a temperature suitable for keeping rice warm, for example, 70°C.

Next, one means of the rice finishing timer will be explained. This timer means is for executing the timer rice cooking, and is configured to arbitrarily set the finishing time and start cooking the rice by the rice cooking control means a certain period of time before the end of the set time. .

The rice finishing timer means includes a time setting means E in the CPU 1e, a rice cooking start determination means including the program contents specified by the flag, a display control means including the program contents specified by the flag, a time setting program contents in the ROM 21, Electronic timer 20. It is composed of a RAM 22, a time display element (time display M10), a timer set key 12, and a control key 13 for rice cooking and timer start. By reading the input state of the timer set key 12 and reading out the contents of the time setting program and the contents of the display program from the ROM 21, the process is carried out as shown in the flowchart of FIG.

In FIG. 22, when the timer set key 120 hour key is pressed, time data is counted up by one hour at a constant cycle while the key is pressed, and the time display element displays I, 2.3. The time is displayed in this way, and the time is set to a limit of 12 hours. Next, when you press the minute key, the display by the hour display element switches to the minute display, and while the minute key is pressed, the minute data is counted up in 10 minute increments at a constant cycle, and the time display element The minutes are displayed in the order of 10, 20, 30, etc. Finally, by pressing the rice cooking/timer start control key 13, the hours and minutes are set and the timer is brought into operation. The time display element is normally in the time display state and switches to minute display only when the minute key is pressed.

If the key is not operated for a certain period of time (for example, 4 seconds) before pressing the rice cooking/timer start control key 13, the display changes to timer start standby mode (
For example, if hours and minutes are displayed alternately) and continued for a certain period of time (for example, 3 minutes), the mode is switched to a cancel mode (for example, 88 is displayed blinking).

In the timer actual operation state, the display control is performed by counting down the time data from the set time and reading out the contents of the display program, as shown in the flowchart shown in FIG. That is, as time passes, the time displayed by the time display element is counted down in units of one hour to display the remaining time until the rice is finished, and when the remaining time is less than one hour, the time displayed by the time display element is displayed. The display changes to Co (abbreviation for COOK) and indicates that the rice has entered the rice cooking operation from rice cooking standby.Then, the temperature of the thermo sensor 6 reaches the t4 temperature and the rice cooking process shifts to the double cooking/uniforming process. At the same time, the Co display by the time display element is switched to the minute display, and the time T8, which is 12 minutes, is displayed during the double-cooking and unevenness process.From then on, the time is counted down in 1-minute increments, and the time until the rice is finished is displayed. The remaining time will be displayed, and the time when 0 minutes is displayed coincides with the end of the double cooking and shading process. When moving to the warming step, the time data is counted up, the elapsed warming time is displayed by the time display element, and the time is counted up in units of one hour.

On the other hand, the determination to start rice cooking is made by determining whether the remaining time until the finished time has reached 10 hours (a shorter time than 1 hour), and when the To time has arrived, the rice cooking control means starts the rice cooking. The above To time is T, , T2. T4. T7
．． Determined based on the total time of T8. In making this decision, T., T2. There is no problem because each time period of T4 and T8 is a constant time, but as explained in the previous cooking process, 17 hours includes unstable elements, so it is necessary to consider how long to allow for 17 hours. be. However, as explained earlier, 17 hours is a nearly constant time, although there is some variation, so it was determined based on experimental data, and 11 hours was determined based on experimental data.
If we determine 10 hours including each time of T2T4T8,
Although there is a difference between the To time and the time actually required from the start of rice cooking to the completion of the rice, the difference can be kept extremely small when viewed from the overall I''iTo time.

In addition, in the time display section 10, from Co display to double cooking,
The time required to switch to the minute display upon starting the unevenness process is calculated to be 48 minutes, but in reality this does not necessarily match because the unstable time T7 is included. However, the time period including T7 is displayed using Co and does not display time, and the time difference is extremely small. Moreover, the end of the double cooking/smoothing process coincides with the 0 display, so users can rely on it. It is possible to almost accurately obtain rice that is most ready to eat at a set desired time without impairing its quality.

Here, rice cooking using a rice finishing timer means, ie, timer rice cooking, will be briefly explained with reference to the flowchart shown in FIG.

If you want to finish 4 cups of rice after 12 hours under standard voltage and brown it to the standard degree, first wash the 4 cups of rice, place it in the inner pot 4, and add water accurately to the specified water level. After filling, the inner pot 4 is placed inside the outer pot 2 and the lid is closed. Next, insert the power plug into the outlet and turn on the power.
1 by pressing the time key of timer set key 12.
The timer is set to 2 hours, and then the rice timer is brought into operation by pressing the rice cooking/timer start control key 13.

Then, as time passes, the remaining time appears on the time display section 10.
It is displayed in time increments, and when 11 hours have passed and the remaining time is less than 1 hour, the time display section 10 shows the Co.
is displayed, indicating that the rice cooking has entered the standby state.

Furthermore, when time passes and the remaining time becomes To waiting time,
Rice cooking starts and the primary heating process is executed, and after T1 time has elapsed, the process moves to the secondary preheating process, and after 12 hours have elapsed, the process moves to the capacity determination process. In this capacity determination process, the set temperature is increased by 2 degrees Celsius every fixed time T5, and an intermittent control method of ON-MAX for 15 seconds and FF-FIX for 5 seconds is executed, so that the temperature of the rice cooking heater 3 during this period is increased. The energization time is accumulated, and this accumulated time is collected as rice cooking capacity determination data. Then, when 14 hours have passed, the rice cooking capacity is determined based on the power supply voltage, timer rice cooking/immediate rice cooking, and the rice cooking heater's cumulative energization time, the corresponding heating duty is determined, and the next stage of cooking is started. Move on to the process. In addition, in the case of this rice cooking example, (2
-4), and the heating duty corresponding to the region (2-4) is selected.

When moving to the cooking step, the rice is cooked by heating at the previously determined heating duty.

When the temperature reaches the temperature t4 of the thermosensor 6 and the rice is cooked, the time goes to the double-cooking/uniforming step, and at the same time, 18 hours, ie, 12 minutes, is displayed on the time display section 10.

Note that before entering the double-cooking/unevening process, the degree of charring is set to "standard" by operating the charring adjustment control key 13.

In the double-cooking/uneven process, double-cooking and browning are executed by controlling the rice cooking heater 3 as shown in FIG. When the screen is displayed, the process ends and the process moves to the heat retention process. Therefore, at this time, approximately 12 hours after pressing the rice cooking/timer start control key 13, the rice that has been sufficiently uniformed and is ready to eat will be obtained. The minute display during the cooking and steaming process is not limited to timer cooking, but is also done when cooking rice immediately.

In the above embodiment, the primary heating step is executed for a certain period of time, but the gist of the present invention can also be achieved by shifting to the secondary preheating step when the temperature of the thermosensor 6 reaches the tl temperature. It's not something to deviate from.

In addition, the present invention is not limited only to the embodiments described above and shown in the drawings, and it is of course possible to carry out the invention by changing the temperature, time, etc. as appropriate without departing from the scope of the invention.

(Effects) As described above, in the present invention, by continuously supplying electricity to the heater, the maximum output of the heater is used to heat the heater to a temperature slightly higher than normal temperature, and then over a predetermined period of time, the temperature rises to the start temperature of the capacity determination process. By gradually increasing the temperature, rice can not only absorb enough water, but also suppress fluctuations in water absorption due to initial water temperature, ambient temperature, etc., and accurately judge rice cooking capacity. You can get rice with less uneven cooking.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the general structure of the rice cooker of the present invention, Fig. 2 is a front view of the operation panel portion of the above, Fig. 3 is a diagram of the heater circuit 1 of the above, Fig. 4 is a block diagram of the entire control circuit of the above, Figure 5 is the main flowchart of the same as above, Figure 6 is a curve diagram showing the relationship between the elapsed time from the start of rice cooking to keeping it warm and the temperature change of the thermosensor, and Figures 7 and 8 are the same as above - secondary and secondary preheating. Flowchart of the process, the 9th picture is an explanatory diagram showing the intermittent control state of the rice cooking heater as above, Figure 10 (aXb) is an explanatory diagram for comparing continuous energization and intermittent energization of the rice cooking heater, and Figure 11 is the same as the above capacity. 12 is a flowchart for collecting judgment data in the judgment step; FIG. 12 is a diagram showing changes in the set temperature in the capacity judgment step; FIG. 14 is a rice cooking capacity determination flowchart in the same capacity determination process as above, FIG. 15 is experimental data showing the relationship between rice cooking heater energization cumulative time and rice cooking capacity in the same as above capacity determination process, FIG. 16 is a rice cooking capacity determination flowchart in the same as above, and 17th The figure is an explanatory diagram showing the control state of the rice-cooking heater in the above-mentioned cooking process, Fig. 18 is a flowchart of the above-mentioned cooking process, Fig. 19 is a flowchart of the above-mentioned double-cooking/mixing process, and Fig. 20Fa) 21 to (c) are diagrams showing the relationship between the temperature change of the thermosensor and the energization to the rice cooking heater in the double-cooking/uniformity process as above, and FIG. 21 is an explanatory diagram showing the control state of the warming heater in the warming process as above, FIG. 22 is a timer setting flowchart same as above, and FIG. 23 is a time display flowchart same as above. 3: Rice cooking heater, 4: Inner pot, 6: Thermosensor, 18
: Microcomputer. Agent Patent attorney Aihiko Fukushi (and 2 others) /3 /
3 β γ FIG. Patent applicant address 22-22 Nagaike-cho, Abeno-ku, Osaka 545 Name (504) Sharp Corporation Saeki Akira Representative Saeki Akira 4, Agent address 545 Nagaike-cho, Abeno-ku, Osaka No. 22 No. 22 Voluntary Issue 6. To those subject to amendment... '' has been corrected to ``When the temperature drops further, power supply to the rice cooking heater 23 will be restarted.''that's all

Claims (1)

[Claims] 1. A preheating step, a capacity determination step of collecting rice cooking capacity determination data and determining the rice cooking capacity based on the data, and a step of cooking rice with a heating power according to the determination result in the previous step, in sequence. The rice cooker is equipped with a thermosensor that detects changes in the temperature of the food to be cooked via the pot, and the preheating step is performed by continuously supplying electricity to the heater until the temperature of the thermosensor reaches a temperature t1 that is slightly higher than room temperature. A primary heating step in which the food to be cooked is heated with the maximum output of the heater, and a heating step in which the set temperature is increased sequentially and the food is heated to reach a temperature t2 that is higher than the set temperature and the temperature of the thermosensor. A rice cooker comprising a secondary preheating step. 2. The rice cooker according to claim 1, wherein both the secondary and secondary preheating steps are performed for a certain period of time.