JPH0632019Y2 - rice cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial field of application) The present invention relates to a rice cooker that has a heating means for heating a container for cooking rice and controls the input of the heating means to cook rice. ,
Particularly, it relates to a rice cooker capable of selecting the hardness of rice.

(Prior Art) In recent years, in this type of rice cooker, it has become possible to select soft, standard, or hard rice according to the taste of the user.

A general structure of a rice cooker of this type is shown in FIG. 8, 1 is a main body having an inner case 2 and an outer case 3, 4 is a lid, and 5 is a container for rice cooked in the inner case 2. , 6 is a rice cooking heater serving as heating means provided at the bottom of the inner case 2, 7 is a heat retaining heater also serving as heating means provided on the side surface of the inner case 2 and the inner surface of the lid 4, and 8 is elastic at the outer bottom of the container 5. It is a cup-shaped heat-sensing portion provided so as to be in pressure contact, and a temperature sensor 9 for detecting the temperature of the container 5 is provided inside. Reference numeral 10 denotes an electronic circuit unit that controls the inputs of the rice cooking heater 6 and the warming heater 7 based on the temperature detection information from the temperature sensor 9 and the like, and is provided at the bottom of the outer case 3. A container 5 is removably housed in the inner case 2, and an upper opening of the container 5 is closed by a lid 4.

Then, for example, when cooking rice having a standard hardness, the container 5 is taken out from the inner case 2, and the required amount of washed white rice and the required amount of water corresponding to the amount of the polished rice are put into the container 5. After housing, the container 5 is then inserted into the inner case 2, the opening is closed by the lid 4, and a start switch (not shown) is turned on in this state manually or by a timer. In response to this, the input to the rice cooking heater 6 is controlled via the electronic circuit unit 10, and the rice is cooked through a predetermined process shown in FIG.

FIG. 9 shows the relationship between the temperature change of the container 5 and the input state of the rice cooking heater 6 with the passage of time. First, hot water is cooked for 15 minutes in response to turning on of the start switch. As shown in Japanese Patent Laid-Open No. 52-66074, this hot water cooking process is to maintain a constant temperature of about 45 ° C., which is a temperature slightly lower than the gelatinization temperature of rice, regardless of the water temperature and the rice cooking capacity. 6% to 6% (eg 1000W)
ON-OFF-ON-OFF control is performed for 15 minutes by the input of, and the water in the container 5 is heated to an appropriate temperature by such control, and the water permeates into the rice grains sufficiently.

After such hot water cooking is performed, a substantial rice cooking process is started. First, the rice cooking heater 6 is energized with 100% input. Due to this energization, the temperature of the container 5 gradually rises, and the rice cooking capacity in the container 5 is detected during that time, that is, while the temperature of the container 5 rises from 70 ° C to 80 ° C. This capacity detection is calculated from the time T required for the temperature of the container 5 to rise from 70 ° C to 80 ° C. That is, when the amount of rice is large, the time T becomes long. Therefore, for example, when T <55 ″, it is determined that the amount is small and when T ≧ 55 ″, the amount is large.

The boiling detection is started when the temperature of the container 5 reaches a predetermined temperature, for example, 94 ° C. This boiling detection is performed by utilizing the fact that when the water in the container 5 starts to boil, the temperature rise of the container 5 is suppressed by the latent heat of vaporization. In other words, the temperature rise of the container 5 becomes 5deg or less after 60 "when the cooking capacity is small from the time when the container 5 reaches 94 ° C and 2'20" when the cooking capacity is also large. The state is detected, and the boiling of the water in the container 5 is determined by this detection.

After such boiling detection is performed, the rice cooker 6
On the other hand, for example, the control of 50% (500 W) input is performed, whereby the boiling of water in the container 5 continues stably.

Due to the continuation of such boiling, the water content in the container 5 decreases,
The rice cooking process is completed when the temperature rise of the container 5 starts again and reaches 120 ° C.

After such a rice cooking process, the 15-minute Murashi process is started. This steaming process is for the rice cooker 6
OFF-ON-OFF-ON-OFF- with 100% input
The ON-OFF control is performed for 15 minutes, and by such control, the container 5 is maintained at a temperature almost equal to that when water is boiling, and the rice in the inside is uneven.

Further, after the purging process, the heat is maintained by the heat-retaining heater 7.

In this way, the rice is first controlled in the hot water cooking process to maintain a constant temperature of about 45 ° C, which is slightly lower than the gelatinization temperature of rice. Before doing so, the water content of rice is made uniform so that the cooked state of rice does not vary.

By the way, as shown in Fig. 10, the water content of 15%, 100g of rice before washing, 10% of water content after washing rice, 20-25% of water content after hot-boiled rice, 120-140% after completion of rice cooking. The water content increases respectively. The water content of standard hardness rice is about 2.3 times the weight of rice before washing rice, the water content is about 63%, and the hard rice is 2.2 times the weight ratio and the water content is 61% each, soft rice is 2.4 by weight
Double the water content and 65% respectively.

In conventional rice cooking, when adjusting the hardness of rice under the same heating conditions, reduce the amount of water for a given amount of rice to obtain hard rice, and conversely increase the amount of water to obtain soft rice. If the ratio of the amount of water to the amount of rice is constant, increasing the heating amount in the substantial rice cooking process accelerates boiling to reduce water absorption during heating and generate a large amount of steam during boiling. To obtain hard rice, and conversely, reduce the amount of heating in the cooking process to slow boiling and increase water absorption during heating, and to reduce the amount of steam generated during boiling to obtain soft rice. I am trying.

(Problems to be solved by the invention) However, in the method of adjusting the amount of water to a certain amount to a certain degree, since the amount of water is too small, the rice is not sufficiently pregelatinized, and the rice tends to have cores remaining. If the amount of water is too large, hot water may spill or scatter during boiling, and on the other hand, the method of adjusting the heating amount in the rice cooking process will increase the cooking time if the heating amount is reduced to obtain soft rice. There was a problem that the difference between the hardness and the softness of the rice was due to the difference in the amount of evaporation during boiling, which made it difficult for the hardness of the rice to appear.

Therefore, an object of the present invention is to provide a rice cooker in which the hardness of rice can be adjusted by variably controlling the control temperature in the hot water cooking process, and the rice having the hardness that matches the taste can be satisfactorily obtained. .

[Configuration of the Invention] (Means for Solving the Problem) The present invention is a container 5 for cooking rice, a heating unit 6 for heating the container 5, and a temperature detecting unit 12 for detecting the temperature of the container 5.
And the temperature condition of the hot water cooking process is set according to a plurality of heating patterns according to the hardness of the rice, and the amount of heat of the heating means 6 in the hot water cooking process is variably controlled based on the set temperature condition. The cooking and heating amount control means 13 is provided.

(Operation) The present invention is controlled by the hot water heating amount control means 13 so as to maintain the control temperature set by the hot water heating temperature setting means 23. When the hot water temperature is high, the water temperature is high and the water absorption amount is high. This gives you soft rice,
On the contrary, when the control temperature is low, the water temperature is low and the water absorption amount is small, so that hard rice can be obtained.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings. Since the entire structure of the rice cooker is the same as that of FIG. 8, the description thereof will be omitted, and the same parts will be described with the same reference numerals.

FIG. 1 is a block diagram, and 11 is an A / D converter that constitutes a temperature detecting means 12 together with the temperature sensor 9 and outputs a signal according to the detected temperature. 13 is the electronic circuit unit
As is well known, the CPU 14 is a control means composed of a microcomputer, and the control means 15 is a clock means 15 and a memory.
16, an input circuit 17, an output circuit 18, etc., and the signal from the operation unit 19 and the signal of the detected temperature of the container 5 are input to the CPU 14 via the input circuit 17, respectively, and output from the CPU 14 via the output circuit 18. Drive circuit 20 based on the generated control signal
The heaters 6 and 7 as heating means are driven and controlled by the display driving circuit 21 and the display unit 22 is driven and controlled by the display driving circuit 21. Further, the control means 13 holds a plurality of types of programs, and controls the driving of the rice cooking heater 6 according to the programs held therein. Further, the operating section 19 is provided with a hot-cooking temperature setting means 23 composed of a hardness selection switch, and the control means 13 is based on a signal from the hot-cooking temperature setting means 23 and the hard-cooking pattern or soft-cooking heating. It has a hot water heating amount control means for variably controlling the heating amount in the hot water cooking process in the same time according to a pattern.

The operation of the present invention configured as described above will be described with reference to FIGS.
It will be described with reference to the drawings.

When the hot water cooking control temperature is set to a low temperature (hard) by the hot water cooking temperature setting means 23 and the start switch is turned on, the control means 13 responds to the control by the hard heating pattern shown in FIG. When the hot water cooking control temperature is set to a high temperature (soft) by the cooking temperature setting means 23, the control means 13 performs control according to the soft heating pattern shown in FIG.

The control by the hard heating pattern (Fig. 2) is described. First, low-temperature hot water cooking is performed for 15 minutes. This hot water cooking process is 3'with 100% input to the rice heating heater 6.
After turning ON-5'OFF, the rice cooking heater 6 is turned ON, and when the container temperature reaches 45 ° C, the rice cooking heater 6 is turned OFF and the rice cooking process is started when 15 minutes have passed since the start of hot water cooking. In addition, "" represents a second of time, and "represents a minute.

In the rice cooking process, 100% input is continuously applied to the rice cooking heater 6 to start capacity detection when the container temperature reaches 70 ° C, and boiling detection is started when the container temperature reaches 97 ° C. The rice cooker heater 6 is controlled to input about 57% to reduce the heating amount, and the rice cooker heater 6 is turned off when dry up is detected.
After that, the steaming process is performed for 15 minutes to maintain the boiling state and complete the cooking of rice.

Controlling by the soft heating pattern (Fig. 3) is described. First, high-temperature hot-pot cooking is performed for 15 minutes. In this hot water cooking process, 100% of the input to the rice cooking heater 6 is 3'ON-5'OFF, and then the rice cooking heater 6 is turned on.
When the container temperature reaches 60 ℃, turn off the rice cooking heater 6
Then, when 15 minutes have passed since the start of hot water cooking, the process moves to the rice cooking process.

During the rice cooking process, the rice heater 6 is continuously energized with an input of about 86% to detect the capacity, and when the boiling temperature detection starts when the container temperature reaches 97 ° C, the rice heater 6 is controlled with 100% input and then boiled. At the time of detection, the rice cooking heater 6 is controlled with an input of about 33% to reduce the heating amount, and at the time of dry-up detection, the rice cooking heater 6 is turned off. After that, a mulling process for 15 minutes is executed to complete the rice cooking.

By the way, it is known that rice can be cooked from a state of having a water content of 20 to 25% with respect to rice, and the relationship between the water temperature and the water absorption rate of rice is as shown in FIG. As can be seen by comparing the a curve, the b curve at a water temperature of 20 ° C., and the c curve at a water temperature of 30 ° C., the higher the water temperature, the faster the water content and water absorption. Therefore, in the hot water cooking process, the soft heating pattern of FIG. 3, which has a higher control temperature than the hard heating pattern of FIG. 2, has higher water content and water absorption at the time of completion of hot water cooking. After that, the process shifts to the rice cooking process. Compared to the hard heating pattern shown in Fig. 2, the soft heating pattern shown in Fig. 3 has a small input of 100% to the rice cooking heater 6 until the start of boiling, and after boiling detection. Also against 57%
Since the input is controlled to be small at 33%, the soft heating pattern in Fig. 3 takes longer to reach the boiling state, absorbs a large amount of water, and reduces the amount of evaporation after boiling.
The rice cooked according to the soft heating pattern shown in FIG. 3 has softer eyes than the rice cooked according to the hard heating pattern shown in FIG. Further, the control by the soft heating pattern of FIG. 3 increases the amount of water absorbed in the hot water cooking process, and as a result, the amount of water not absorbed is smaller than that of FIG. 2, so that the entire rice cooking process of FIG. 2 and FIG. The time is almost the same. In addition, since the amount of water is not adjusted as in the past, the amount of water becomes too small and the rice is not pregelatinized enough, resulting in rice with cores remaining, or too much water spilling hot water. Also, even if you change the heating amount in the rice cooking process to a small amount and change it, the water temperature for hot water cooking is high so that the rice cooking time does not become too long. You can get rice with the right hardness.

Next, a second embodiment of the present invention will be described with reference to the graphs of FIGS. 5 and 6, and a third embodiment will be described with reference to the graph of FIG. The configuration and electrical configuration of the rice cooker in this embodiment are the same as those in the first embodiment, and the description thereof will be omitted.

In this example, control in the case of the same menu and the same water / rice ratio is shown. In FIGS. 5 and 6, the hard heating pattern is as shown in FIG. 3'ON- with approx. 67% input to rice cooker 6
The control of 5'OFF-1'ON-6'OFF is performed, and then the rice cooking process and the unevenness process similar to those in FIG. 2 are performed.
As shown in FIG. 6, the soft heating pattern is a 15-minute hot-water cooking process, which is 3'ON-5'OFF-4'ON- with an input of about 67% to the rice cooking heater 6.
The 3'OFF control is performed, and then the rice cooking process and the mulling process similar to those in FIG. 3 are performed. Also in this control
Similar to the embodiment, the control by the soft heating pattern of FIG. 6 has a higher water temperature in the hot water cooking process than in the control by the hard heating pattern of FIG. 5, and a large amount of water is absorbed, and the heating amount in the rice cooking process is small. Therefore, the amount of water absorption is large and the amount of evaporation is small, so that soft rice can be obtained.

FIG. 7 shows the control in the case of determining the amount of water in the hot water cooking process. At the time of starting the hot water cooking process, 100% input to the rice-cooking heater 6 is made 20 ″ OFF, and the time point P is reached.
_When the container temperature to of ₁ is detected and to ≥ 45 ° C, then 4
0 "ON-20" OFF-40 "ON-20" OFF-40 "O
Controlled N-12'OFF, 40 "O when to <45 ℃
N-20 "OFF-40" ON-20 "OFF-40" ON-
The container temperature t ₁ at the time point P ₂ of 5′OFF is detected, and the temperature tmax at the maximum temperature time point P ₁ during this control is detected, and when t ₁ ≧ tmax−1 is satisfied, it is determined as a small amount, and the hard temperature is determined. In the eye heating pattern, the OFF state of the rice cooking heater 6 is continued when it is determined as a small amount, and when it is not a small amount, 40 ″ ON-6′20 ″ OFF control is performed as shown in FIG. In the eye heating pattern, 40 "ON-6'20" OFF is controlled when it is judged as a small amount, and 40 "ON-20" OFF-40 "ON when it is not a small amount.
-20 "OFF-40" ON-20 "OFF-40" ON-3 '
The control of 20 "OFF is performed as shown in Fig. 7 (B). After that, the hard heating pattern is the same as the rice cooking process and the wiping process shown in Figs. 2 and 5, and the soft heating pattern is the first. Three
The rice cooking process and the Murashi process are carried out in the same manner as in Fig. 6 and Fig. 6.
Thus, the heating amount is controlled according to the rice cooking capacity, and the rice having the desired hardness can be obtained regardless of the rice cooking capacity.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention. For example, the type of control temperature set by the hot water cooking temperature setting means may be appropriately selected, and the variable control of the heating amount may be performed by ON / OFF of the heater or control of the energization rate.

[Effects of the Invention] The present invention has a container for cooking rice, a heating means for heating the container, a temperature detecting means for detecting the temperature of the container, and a plurality of temperature conditions for the hot water cooking process depending on the hardness of the rice. The heating temperature is set according to the heating pattern of No. 1, and the heating temperature of the heating means in the hot water cooking step is variably controlled based on the set temperature state. It is possible to provide a rice cooker in which the hardness of rice can be adjusted by the variable control and the rice having the hardness that matches the taste can be satisfactorily obtained.

[Brief description of drawings]

1 to 4 show a first embodiment of the present invention, FIG. 1 is a block diagram, FIG. 2 is a graph showing control of a hard eye heating pattern, and FIG. 3 is a control of a soft eye heating pattern. Fig. 4 is a graph showing the relationship between temperature and water absorption rate,
5 and 6 show a second embodiment of the present invention,
Fig. 6 is a graph showing the control of the hard heating pattern, Fig. 6 is a graph showing the control of the soft heating pattern, Fig. 7 (A).
(B) is a graph showing a third embodiment of the present invention, FIG. 8 is a vertical sectional view showing a general rice cooker, FIG. 9 is a graph showing a process of cooking standard rice, and FIG. 10 is a process. It is a graph which shows the relationship between the water content of rice and rice. 5 ... Container 6 ... Rice-cooking heater (heating means) 9 ... Temperature sensor (temperature detection means) 11 ... A / D converter (temperature detection means) 13 ... Control means (hot-cooking heating amount control means) 23 ... Hot-cooking temperature setting means

Claims (1)

[Scope of utility model registration request] 1. A container for cooking rice, a heating means for heating the container, a temperature detecting means for detecting the temperature of the container, and a plurality of heating patterns in which the temperature condition of the hot water cooking process depends on the hardness of the rice. The rice cooker is characterized by being set according to the above-mentioned temperature condition and variably controlling the heating amount of the heating means in the hot water cooking process based on the set temperature state.