JP2006042864A - Rice cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rice cooker for automatically optimizing a cooking procedure in temperature, time, or the like. <P>SOLUTION: The rice cooker 1 has a control means 8 for obtaining an estimated volume V<SB>2</SB>of rice cooked from the rate of rise in water temperature and changing the cooking procedure according to the estimated volume V<SB>2</SB>. The rice cooker 1 has a storage means for storing historical estimated volumes V<SB>2</SB>, and the control means 8 changes the cooking procedure according to the historical estimated volumes V<SB>2</SB>. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rice cooker.

  When cooking rice, it is important to allow the rice to absorb water sufficiently and to make the time from the start of gelatinization until the excess water disappears to an appropriate length. The optimum water absorption rate for rice is about 30%. The higher the temperature, the higher the water absorption rate. However, when the temperature is higher than the gelatinization start temperature, the surface becomes gelatinized and hardly absorbs water. The cooking time from the start of gelatinization until the excess water disappears is optimally about 18 minutes.

  As shown in FIG. 7, the conventional rice cooker has a preheating process for heating and absorbing water at a temperature not in the range of gelatinization, a boiling process for boiling water, and gelatinizing the rice while maintaining the boiling state, and excess moisture. The boiling maintenance process is performed to evaporate the rice, and depending on the model, the cooking is automatically cooked as a series of rice cooking processes until steaming for a predetermined time.

  In the preheating process, it is important to maintain the temperature of rice and water at the set temperature, but depending on the water temperature at the start of rice cooking, the environmental temperature and the amount of rice cooked, the measured value of the temperature sensor provided outside the inner pot There may be a difference between the actual rice and water temperature. In particular, when the amount of cooked rice is large, the measured value by the temperature sensor during heating tends to be higher than the actual temperature of rice and water.

  Moreover, in the boiling maintenance process, it is important to optimize the amount of heat (input power) applied from the heating means in accordance with the amount of rice cooking. As shown in FIG. In general, the input power in the boiling maintenance step is generally adjusted according to the estimated capacity. However, the correct amount of cooked rice could not be estimated from the water temperature rise rate due to seasonal fluctuations.

With respect to the above problems, in Patent Document 1, the water absorption temperature and time are changed depending on the water temperature at the start of rice cooking, and in Patent Document 2, actual rice and water are increased due to a slight increase in temperature in the water absorption process. The preheating time is changed by estimating the temperature by fuzzy reasoning. Moreover, in patent document 3, heating is stopped when preheating temperature is reached, the amount of rice cooking is estimated by measuring the amount of overshoot of temperature, and the preheating time is changed. Moreover, in patent document 4, the reference value at the time of determining the estimated amount of rice cooking from the temperature increase rate in a boiling process is correct | amended with the water temperature at the time of a rice cooking start. Furthermore, in patent document 5, the amount of heating is increased / decreased with the cooking time at the time of the last rice cooking.
Japanese Patent No. 3028983 Japanese Patent No. 2613495 Japanese Patent No. 27329797 Japanese Patent No. 3129376 Japanese Patent No. 2923351

  However, when rice cooking is started immediately after preparing rice and water, there are many cases where there is an error between the output of the temperature sensor at the start of rice cooking and the actual water temperature or the ambient temperature is not reflected. And since the water temperature rise at the time of preheating is slight, it is difficult to estimate the amount of rice cooking accurately. Moreover, since the length of cooking time is influenced by many factors that change each time, correction of the amount of heating at the next cooking is not necessarily corrected in the preferred direction based only on the result. Furthermore, there has been a problem that a correct cooking procedure cannot be selected due to variations during manufacture of the rice cooker, changes in the output of the sensor and the output of the heating means over time.

  In view of the above problems, an object of the present invention is to provide a rice cooker that automatically optimizes cooking procedures such as temperature and time.

  In order to solve the above problems, a rice cooker according to the present invention is a rice cooker having a control means for obtaining an estimated capacity of the amount of rice cooked according to the rate of increase in water temperature and changing the cooking procedure according to the estimated capacity. Storage means for storing the estimated capacity, and the control means changes the cooking procedure according to the past estimated capacity.

  According to this configuration, the estimated capacity estimated from the information obtained each time the rice is cooked has a large error, but the user performs approximately the same amount of rice every time, so refer to a plurality of estimated capacities estimated in past cooking. And you can guess the rice cooking capacity more accurately and choose the appropriate procedure to cook rice.

  Moreover, the rice cooker of this invention WHEREIN: The said control means may change at least any one of the temperature and time of a preheating process among the said cooking procedures.

  According to this configuration, although the amount of heating is small in the preheating step and the error increases even if the amount of rice cooking is predicted, the procedure of the preheating step can be optimized by referring to the past estimated capacities.

  Further, in the rice cooker of the present invention, the estimated capacity stored by the storage means is a secondary estimated capacity determined by a water temperature increase rate in a boiling process, and the control means is determined by a water temperature increase rate in a preheating process. The cooking procedure may be changed according to the primary estimated capacity and the plurality of past secondary estimated volumes.

  According to this configuration, a safe cooking procedure can be selected from the results of both a plurality of estimated volumes in the past and the estimated volume determined primarily.

  Moreover, the rice cooker of this invention WHEREIN: The said control means may change the reference value for discriminating the said secondary estimated capacity | capacitance according to the said primary estimated capacity | capacitance.

  According to this configuration, the determination error of the secondary estimated capacity due to changing the temperature of the preheating process can be reduced.

  Further, in the rice cooker of the present invention, the control means determines the primary estimated capacity by comparing the time from the start of preheating to the rise to a predetermined water temperature with a threshold value, and sets the water temperature at the start of preheating. The threshold value may be changed accordingly.

  According to this configuration, the water temperature increase rate can be measured as long as possible, so that the accuracy of determining the primary estimated capacity can be increased.

  Moreover, the rice cooker by this invention is a rice cooker which has a control means which changes the cooking procedure according to the said estimated capacity | capacitance by calculating | requiring the estimated capacity | capacitance of rice cooking amount by comparing a water temperature increase rate with a reference value, The storage unit may store a plurality of past execution times of the cooking process, and the control unit may change the reference value according to the plurality of past execution times.

  According to this configuration, when the execution time of a predetermined cooking process is out of the optimum conditions from a plurality of past cooking results, the estimated value is automatically determined as the estimated capacity is not appropriate. To correct. For this reason, the estimation precision of a capacity | capacitance improves and it can cook rice with a suitable cooking procedure. In addition, even if the sensor and heating output change over time, the rice can be cooked with an appropriate cooking procedure by correcting the reference value.

  Further, in the rice cooker of the present invention, there are a plurality of the reference values, the storage means stores a plurality of past estimated capacities, and the control means determines the reference values according to the past plurality of estimated capacities. It may be specified which of these is to be changed.

  According to this configuration, even when the cooking procedure is not optimal only for a specific amount of cooked rice, only the reference value for the specific estimated capacity can be corrected, so even if the amount of cooked rice is not constant, I can cook rice.

  Further, in the rice cooker of the present invention, there are a plurality of the reference values, the storage means stores the number of heating outputs in a predetermined section in a plurality of past preheating steps, and the control means includes the plurality of past heating outputs. Depending on the number of times, it may be specified which of the reference values is changed.

  According to this configuration, the reference value of the water temperature increase rate that determines the estimated capacity is specified by the number of heating outputs in the preheating process, which is a different criterion, so that the reference value greatly deviates. Even if this is the case, an appropriate correction target can be identified.

  As mentioned above, the rice cooker of this invention can optimize cooking procedures, such as temperature and time automatically, and can always cook rice appropriately.

  Embodiments of the present invention will be described below with reference to the drawings.

Drawing 1 is a sectional view of rice cooker 1 of an embodiment of the present invention. The rice cooker 1 includes a main body 2 and a lid 3, and an inner pot 4 is accommodated in the main body 2. An inner lid 5 is attached to the lid 3 so as to seal the upper opening of the inner pot 4. The rice cooker 1 cooks by heating the inner pot 4 with a heating coil 6 which is a heating means provided in the main body 3. Further, the main body 3 is provided with a temperature sensor 7 that is in contact with the side surface of the inner pot 4 and detects the temperature of the inner pot 4, and the control circuit 8 that is a control means is heated according to the detected temperature of the temperature sensor 7. The output of the drive circuit 8 that drives the coil 6 can be increased or decreased. Further, the control circuit 8 can transmit / receive data to / from the storage device 10 which is a nonvolatile storage unit made of E ² PROM.

Next, the time change of the detected temperature of the temperature sensor 7 when cooking rice with the rice cooker 1 in FIG. 2 is shown. In the rice cooking process, the rice and water in the inner pot 4 are heated to a preheating temperature T _P of 42 ° C., for example, and then maintained at the preheating temperature T _P for a predetermined time, so that the rice absorbs water and water Boiling process, boiling process for maintaining the boiling and gelatinizing the rice and then evaporating excess water, and steaming process for steaming for a predetermined time.

The cooking procedure such as the output of the heating coil 6 and the holding time in each step is changed according to the amount of rice cooked, but the amount of rice cooked is estimated by the rate of increase in water temperature. In rice cooker 1, which is primary determined in any of a large capacity and a small capacity in the preheating step primary presumed volume V ₁ is obtained, the secondary determination to any capacity rank R ₂ of 7 stages at the boiling step The secondary estimated capacity V ₂ is obtained.

In primary determination, in the preheating step, if the preheating time t ₁ it took to increase from the preheating start to a predetermined temperature is the primary determination threshold t _S1 or primary presumed volume V ₁ was located at large If the preheating time t ₁ is less than the primary determination threshold value t _S1 , it is determined that the primary estimated capacity V ₁ is a small capacity.

In the secondary discrimination, in the boiling process, the boiling time t ₂ required for a predetermined temperature rise is set as one index to one of the six capacity ranks R ₂ by fuzzy inference. Each median value T _S2 shown in Table 1 below is a reference value that defines each capacity rank R ₂ , and when the boiling time t ₂ is equal to the median value T _S2 , the secondary estimated capacity V ₂ has a median value T _S2 of membership function indicating that it belongs to the capacity rank R ₂ defined becomes the maximum.

In the rice cooker 1, the resulting secondary speculated volume V ₂ of the secondary determination, as shown in Table 1, the energization rate to the heating coil 6 in boiling maintain process (heating amount) is determined. For example, secondary presumed capacity V ₂ is equal the rank 4, the drive circuit 8 drives the heating coil 6 by the duty ratio 9/15. Then, the rice cooker 1, to measure the cooking time t _B required for the boiling-preserving process, as compared to the appropriate time t _SB of Table 1, so that the duty factor of the heating coil 6 can determine whether a proper It has become.

The storage device 10 is adapted and secondary presumed capacity V ₂ of capacitor rank value R ₂ and cooking time t _B for example to store the past eight times, also, the median t _S2 also storage device 10 Can be rewritten.

Figure 3 shows a flow of determination for determining the preheating temperature T _P. In rice cooker 1, the primary presumed volume V _1, is adapted to determine the preheating temperature T _P from the past secondary guess volume V ₂ of capacitor rank value R ₂ Prefecture. First, in step S1, the water temperature T ₀ at the start of preheating is equal to or higher than the lower limit temperature T _{S1 of} 13.2 ° C. and lower than the boundary temperature T _S2 of, for example, 18.2 ° C., or the water temperature T at the start of preheating in step S2. It is confirmed whether ₀ is _{equal to} or higher than the boundary temperature T _S2 of, for example, 18.2 ° C. and _lower than the upper limit temperature T _S3 of, eg, 24.3 ° C. Temperature _{T 0} is lower than the lower limit temperature _{T S1} at step S1, or if the _{T S3} or in step S2, setting the preheating temperature _{T P} in step S3, a common preheating temperature low _{T L} (e.g., 42 ° C.) . If the water temperature T ₀ is equal to or higher than the lower limit temperature T _S1 and lower than the boundary temperature T _{S2 in} step S2, the primary determination threshold value t _S1 is set to ta (eg, 360 seconds) in step S4, or in step S2. If the water temperature T ₀ is equal to or higher than the boundary temperature T _{S2 and lower} than the upper limit temperature T _S3 , the primary determination threshold value t _S1 is set to tb (for example, 210 seconds) in step S5, and in general, from the start of preheating in step S6. measuring the preheating time t ₁ until the rise specific preheat temperature T _L. Step S7 in the preheating time t ₁ is at the primary determination threshold t _S1 above, and the past eight secondary guess volume V ₂ of capacitor rank value R ₂ of average preheating capacitance rank reference value in step S8 if V _S1 above, to set the preheating temperature _{T P} to a high temperature _{T H} (for example, 60 ° C.) in step S9. However, if preheat time t1 is less than the primary determination threshold t _S1 in step S7, the average value of the capacitance rank value R ₂ of the past eight secondary guess volume V ₂ is preheated capacitance rank reference value in step S8 if it is less than V _S1, it sets the preheat temperature _{T P} in a low temperature _{T L} at the step S3. Then, a predetermined time at step S10, driving the heating coil 6 so as to maintain the preheating temperature T _P.

The effect of determining the preheating temperature T _P by the control, in order to measure is higher than the actual rice and the water temperature by the temperature sensor 7 as cooking capacity is large, the actual rice and water when cooking capacity is large The problem is that water absorption is insufficient due to the low temperature. Further, presumed capacity V ₁ by preheating time t ₁ the error is large, the user necessarily because the past cooking amount not necessarily the same amount and rice, only either the actual rice and the water temperature increases Too much, the rice surface is gelatinized and can absorb water almost completely, and cooking rice fails. Therefore, in this embodiment, since both of the determination results are large in capacity and the preheating temperature _TP is increased only when it is certain that the actual amount of cooked rice is large, the amount of cooked rice is small despite the small amount of cooked rice. , without fail the cooking performing preheating of hot T _H, even if the prediction cooking amount is to be a small amount was out, and not be the best cooking but a tolerance conventional cooker Similar rice cooking results are obtained.

In the present embodiment, although the preheating temperature T _P to a high temperature T _H when the primary presumed volume V ₁ and the past second guess volume V ₂ are both large, without changing the preheating temperature T _P it may be a long time to maintain the preheat temperature T _P to. In this case, the time required for rice cooking becomes longer, but even when the actual amount of cooked rice is small, the primary estimated capacity V ₁ and the past estimated secondary capacity V ₂ are both large. It is safe because there is no failure without water absorption.

Further, in the present embodiment, since the preheating time t ₁ of between from preheating initiation reaches a temperature T _L as compared with the primary determination threshold t _S1, it can lengthen the time for measuring the water temperature increase rate Measurement error is small. In addition, when the water temperature at the start of preheating is lower than the lower limit temperature T _S1 or higher than the upper limit temperature T _S3 , the initial condition is not in the normal range, so even if the water temperature increase rate is measured, an unexpected measurement error is included. Probability is high. For this reason, preheating at a safe normal temperature _TL is performed to avoid danger. Also, if dividing the elevated temperature in the preheating time t _1, but the water temperature increase rate is determined, the pre-heating, contains many error factors the difference between the room temperature shorter heating time is carried out at a small temperature range . For this reason, it is sufficient to consider various errors only by dividing the water temperature at the start of preheating into a plurality of temperature bands and setting the primary determination threshold value t _S1 for the preheating time t ₁ for each section.

Next, FIG. 4 shows the flow of determination of the secondary guess volume V _2. In step S11, the boiling process, the temperature for example from 60 ° C. to 90 ° C. to measure the boiling time t ₂ until the rise. In step S12, the preheating temperature T _P in the preheating step to confirm whether a any low T _L and a high temperature T _H, when the preheating temperature T _P was hot T _H, the capacitance stored in the storage device in step S13 Using the value obtained by subtracting 10 from the median value t _S2 of ranks 1 to 6, it is estimated in step S14 which capacity rank the rice cooking amount belongs to by fuzzy inference, and the secondary estimated capacity V ₂ to determine the capacity rank value _{R 2.} In step S13, the contents stored in the storage device are not rewritten, and only at that time, each median value _tS2 is corrected to be negative. Also, if the preheating temperature T _P in step S12 was low T _L, the value of the median t _S2 of each capacity rank 1-6 accept the value stored in the storage device, by fuzzy inference in step S14 to determine the secondary guess capacity rank value _{R 2} of the capacity _{V 2.}

According to this control, the secondary estimated capacity V ₂ can be accurately obtained. This higher preheating temperature T _P, boiling time t ₂ that is shorter known empirically, it is ideal to set the same median and Table 1 for each preheating temperature T _P but by correcting the median t _S2 as a reference for determining the secondary guess volume V ₂ by preheating temperature T _P, without setting a central value for each preheating temperature T _P, accurate capacitance discrimination This is because it becomes possible.

Next, FIG. 5 shows a procedure for correcting the median value t _S2 at the time of secondary discrimination. In rice cooker 1, when the cooking is finished, the cooking time t _B as compared to the appropriate time t _SB determines whether the cooking procedure was appropriate, depending result, more appropriately change the cooking procedure for Future the median t _S2 at second discrimination corrected and adapted to rewrite the value of the median T _S2 stored in the storage device to. Further, although all the reference values may be corrected simultaneously, in this embodiment, as shown in Table 1, the capacity rank R _{2 is set} to ₂ of the relatively small capacity S group and the large capacity L group. It is divided into one capacity group and corrected for each capacity group.

The correction procedure for the median value t _S2 is as follows. After the boiling maintaining step, first, in step S21, the cooking time t _B is the past three times, and the appropriate time in Table 1 corresponding to the secondary estimated capacity V ₂ during cooking continuously. If it is confirmed that it is longer than t _SB, the median value t _S2 of the L group is decreased when the capacity rank R ₂ of the secondary estimated capacity V ₂ belongs to the L group in all the past three times (step S22). correction was carried out for (step S23), performs a correction to reduce the median _{t S2} of S group when a capacity rank _{R 2} of at last three secondary presumed capacity _{V 2} belongs to a group S (step S24) (Step S25). Capacity rank R ₂ of the secondary guess capacity V ₂ of the past 3 times is not corrected in the case of disagreement. If it is confirmed in step S26 that the cooking time t _B has been shorter than the appropriate time t _SB in Table 1 corresponding to the secondary estimated capacity V ₂ in the past three times in the past, the past three times. both when the capacity rank _{R 2} secondary guess volume _{V 2} belongs to L group (step S27) to perform correction to increase the median _{t S2} of L group (step S28), with the last three secondary guess If the amount rank _{R 2} volume _{V 2} belongs to a group S correction is performed to increase the median _{t S2} of S groups (step S29) (step S30). Capacity rank R ₂ of the secondary guess capacity V ₂ of the past 3 times is not corrected in the case of disagreement.

The effect of this correction is that when the cooking time t _B is longer than the appropriate time t _SB , it is considered that the heating amount by the heating coil 6 is insufficient, so the median t _S2 for determining the secondary estimated capacity V ₂ is reduced. Then, when cooking rice under the same conditions, the secondary estimated capacity V ₂ is determined to be a larger capacity rank R ₂ , so that the energization rate is increased and the heating amount by the heating coil 6 is increased so that cooking time is increased. t _SB can be brought close to the appropriate time t _SB . If the cooking time t _B is shorter than the proper time t _SB is its opposite.

In the present embodiment, the median value t _S2 is corrected only when the determination results of the cooking time t _B and the capacity group of the secondary estimated capacity V ₂ are continuously the same three times in the past. The necessity of correction may be determined based on the average value of the time t _B , the median value t _S2 of the capacity group to which the majority of the secondary estimated capacity V ₂ belongs, or 2 2 belonging to the same capacity group. The cooking time t _SB at the next estimated capacity V ₂ may be picked up to determine whether correction is necessary. In addition, the appropriate time t _SB may have a width. In this case, the appropriate time t _SB is different in step S21 and step S26.

Further, in the present embodiment, the secondary estimated capacity V ₂ is determined by fuzzy inference, but the capacity rank value R ₂ may be determined based on a threshold value indicating the boundary of each capacity rank. Moreover, as shown in Table 1, the appropriate time T _SB is set to one value for two capacity ranks. This is the kind of rice, such as white rice and non-washed rice, In order to store the same data as in Table 1 for each user preference, the data amount is saved.

Further, FIG. 6 shows a correction procedure that is an alternative to the correction procedure of FIG. In this correction procedure, a capacitor group median t _S2 to change target (L group The S group), and IH output times N _I reference the drive device 8 counts the number of IH output pulses output in the preheating step made is to determine with greater or not than IH output reference number N _S.

The correction procedure of this median value t _S2 is that the cooking time t _B was longer than the appropriate time t _{SB of} Table 1 corresponding to the secondary estimated capacity V ₂ at the time of cooking three times in the past in step S31. If confirmed, corrects both past three _{N I} is to reduce the median _{t S2} of L groups is greater than or equal _{N S} (step S32) (step S33), with the last three _{N I} is _{N S} is less than performs correction to reduce the median _{t S2} of S groups (step S34) (step S35). Capacity rank R ₂ of the secondary guess capacity V ₂ of the past 3 times is not corrected in the case of disagreement. If it is confirmed in step S36 that the cooking time t _B has been shorter than the appropriate time t _SB in Table 1 corresponding to the secondary estimated capacity V ₂ in the past three times in the past, the past three times. both If _{N I} is not less than _{N S} (step S37) to perform correction to increase the median _{t S2} of L group (step S38), if both past three _{N I} is less than _{N S} (step S39) Correction for increasing the median value t _S2 of the S group is performed (step S40). If past three IH output times N _I and IH output reference number N _S and the comparison result does not match no correction.

According to this correction procedure, there is no unreasonable that identifies a median t _S2 to be corrected by volume rank R ₂ which is determined based on the median t _S2 to be corrected, the median t _S2 is larger from the correct value Even if it is off, the correction target can be appropriately specified.

In this correction procedure, the last three times, but to correct the median t _S2 only if IH output count N _I and IH output reference number N _S and the comparison result of the are the same continuously, IH output may be determined the necessity of the correction by the average value of the number N _I, may be corrected median t _S2 volume group corresponding to the frequently IH output number N _I, also, IH a range of the cooking time t _SB when the number of output times N _I may determine the necessity of a pickup to correct.

Sectional drawing of the rice cooker of this invention. The graph which shows the temperature change in the rice cooking process of the rice cooker of FIG. The flowchart of the primary discrimination | determination of the rice cooking amount in the rice cooker of FIG. The flowchart of the secondary discrimination | determination of the rice cooking amount in the rice cooker of FIG. The flowchart of the correction | amendment of the secondary discrimination | determination reference value of the amount of rice cooking in the rice cooker of FIG. FIG. 6 is a flowchart of an alternative for correcting the reference value of FIG. 5. The graph which shows the temperature change in the rice cooking process of the conventional rice cooker.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rice cooker 2 Main body 3 Lid 4 Inner pan 5 Inner lid 6 Heating coil 7 Temperature sensor 8 Drive circuit

Claims (10)

A rice cooker having a control means for obtaining the estimated capacity of the amount of rice cooked by the water temperature increase rate and changing the cooking procedure according to the estimated capacity,
Storage means for storing a plurality of the estimated capacities in the past,
The said control means changes a cooking procedure according to the said several past estimated capacity | capacitance, The rice cooker characterized by the above-mentioned.   2. The rice cooker according to claim 1, wherein the control unit changes at least one of a temperature and a time of a preheating step in the cooking procedure. The estimated capacity stored by the storage means is a secondary estimated capacity determined by a water temperature increase rate in a boiling process,
The said control means changes a cooking procedure according to the primary estimated capacity | capacitance discriminate | determined by the water temperature increase rate of the preheating process, and the said several secondary estimated capacity | capacitance, The rice cooker of Claim 2 characterized by the above-mentioned. .   The said control means changes the reference value for discriminating the said secondary estimated capacity | capacitance according to the said primary estimated capacity | capacitance, The rice cooker of Claim 3 characterized by the above-mentioned.   The control means determines the primary estimated capacity by comparing a time from the start of preheating to a rise to a predetermined water temperature with a threshold, and changes the threshold according to the water temperature at the start of preheating. The rice cooker of Claim 3 or 4 characterized by the above-mentioned. A rice cooker having a control means for obtaining the estimated capacity of the amount of rice cooked by the water temperature increase rate and changing the cooking procedure according to the estimated capacity,
The control means determines the primary estimated capacity based on the water temperature increase rate in the preheating process, determines the secondary estimated capacity based on the water temperature increase rate in the boiling process,
A rice cooker characterized by changing a reference value for determining the secondary estimated capacity in accordance with the primary estimated capacity.   The control means determines the primary estimated capacity by comparing a time from the start of preheating to a rise to a predetermined water temperature with a threshold, and changes the threshold according to the water temperature at the start of preheating. The rice cooker of Claim 6 characterized by the above-mentioned. A rice cooker having a control means for changing the cooking procedure according to the estimated capacity by obtaining the estimated capacity of the rice cooking amount by comparing the water temperature increase rate with a reference value,
Having storage means for storing a plurality of past execution times of a predetermined cooking process;
The said control means changes the said reference value according to the said past several execution time, The rice cooker characterized by the above-mentioned. There are a plurality of the reference values,
The storage means stores a plurality of past estimated capacities,
9. The rice cooker according to claim 8, wherein the control means specifies which of the reference values is changed according to the plurality of past estimated capacities. There are a plurality of the reference values,
The storage means stores the number of heating outputs in a predetermined section in the past plurality of preheating steps,
The rice cooker according to claim 8, wherein the control means specifies which of the reference values is changed according to the plurality of past heating output times.

Images