JP5208152B2 - rice cooker - Google Patents

Description

  The present invention relates to a rice cooker in which a pot-like container containing food such as rice is housed in a main body and cooked.

  In order to cook delicious cooked rice, it is necessary to make the rice absorb enough water before cooking. This is because rice with insufficient water absorption tends to become cooked rice with a core remaining. Therefore, the rice cooking process of the rice cooker is provided with a process called a preheating process that keeps the inside of the pot-like container at a temperature equal to or lower than the gelatinization temperature (60 to 70 ° C.) of rice before boiling and promotes water absorption of the rice. Yes. In the case of rice that is generally distributed in large quantities, the water content is about 15% in the state of polished rice, but water absorption proceeds to about 30% at the end of the preheating process, and the water content is about 60 to 30% when cooked. It becomes delicious rice by becoming 65%.

  However, the ease of water absorption of rice differs depending on the variety and production location of the rice, the storage conditions, the distinction between new and old rice, and the quality. Even when the preheating step is performed at a certain time and temperature, water absorption may be insufficient or excessive depending on the rice used. When the water absorption of rice is insufficient, for example, when the water content is less than 35% even at the stage of starting boiling, the core remains in the cooked rice. Also, if the water absorption of the rice is excessive, for example, if the moisture content of the rice exceeds 50% at the end of the preheating process, there will be almost no water that is not absorbed by the rice at the stage of starting boiling, Moisture does not spread evenly throughout the pan-like container, which may cause uneven cooking. When cooking unevenness occurs, for example, the rice near the bottom in the pan-like container may become too soft, while the upper rice may be cooked in a hard raw state.

Thus, the water absorption of rice is an important item in order to obtain a good-tasting cooked rice.
Therefore, in the past, “brand selection means (the rice brand is classified into at least three grades of brands,“ standard ”group,“ harder than standard ”group, and“ softer than standard ”group depending on the nature of the rice, such as hard and soft). Select one rice type from the classified)), set the rice cooking sequence suitable for each brand group based on the selection of this brand selection means, and control the rice cooking process (For example, refer to Patent Document 1).

Japanese Patent Laid-Open No. 2002-300963 (page 3, FIG. 1)

  However, in the rice cooker described in Patent Document 1, it takes time for the user to bother selecting the rice brand, and if the user does not know the rice brand, the optimal rice cooking sequence cannot be selected. It was.

  This invention is made | formed in order to solve the above subjects, and provides the rice cooker which can cook rice stably and deliciously without making a user trouble.

A rice cooker according to the present invention drives a main body, a pot-shaped container accommodated in the main body, a lid covering the opening of the pot-shaped container, a heating means for heating the pot-shaped container, and the heating means. Control means for controlling , moisture content detecting means for detecting the moisture content of rice put together with water in the pan-like container, and change in the moisture content of rice in the pot-like container detected by the moisture content detecting means A water absorption determining means for determining the ease of water absorption of the rice based on the control means, the control means according to the ease of water absorption of the rice determined by the water absorption determination means. Is to control.

According to the present invention, the ease of water absorption of rice is determined by the water absorption determination means, and the preheating process time is controlled according to the ease of water absorption. For this reason, for example, if it is easy to absorb water, it is possible to suppress excessive water absorption of the rice by shortening the time of the preheating process, and if it is difficult to absorb water, increase the time of the preheating process to promote water absorption of the rice. Since it can do, it can suppress that a core remains in cooking rice, or that cooking unevenness arises.
In addition, since the water absorption judgment means determines the ease of water absorption of rice, information on characteristics affecting the ease of rice absorption (for example, variety, production area, distinction between new rice and old rice, etc.) There is no need for the user to set in advance. For this reason, it is possible to save time and effort for the user to make necessary settings, and to achieve stable cooking even when the above characteristics are unknown.

It is a cross-sectional schematic diagram which shows the structure of the rice cooker which concerns on Embodiment 1. FIG. It is a block block diagram of the moisture content detection means of the rice cooker which concerns on Embodiment 1. FIG. It is a block block diagram of the water absorption judgment means of the rice cooker which concerns on Embodiment 1. FIG. It is a flowchart which shows the operation | movement of the rice cooking process of the rice cooker which concerns on Embodiment 1. FIG. It is a graph which shows transition of the internal temperature of the pot-shaped container in the rice cooking which concerns on Embodiment 1, and a pan bottom temperature. It is a cross-sectional schematic diagram which shows the structure of the rice cooker which concerns on Embodiment 2. FIG. It is a flowchart which shows the operation | movement of the rice cooking process of the rice cooker which concerns on Embodiment 2. FIG.

Hereinafter, embodiments of a rice cooker according to the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a schematic cross-sectional view showing the configuration of the rice cooker according to the first embodiment, FIG. 2 is a block configuration diagram of moisture content detecting means in the rice cooker of the first embodiment, and FIG. 3 is in the rice cooker of the first embodiment. It is a block block diagram of a water absorption judgment means.

  In FIG. 1, a rice cooker 100 includes, for example, a main body 1 whose outer appearance is formed in a bottomed cylindrical shape, and a lid body 10 including an outer lid 10a and an inner lid 10b. The main body 1 includes a container cover 2, a heating coil 3 as a heating means, a pan bottom temperature sensor 4, a hinge portion 6 that supports the lid so as to be opened and closed, a time measuring means 7, a control means 8, and a water absorption determining means. 16. Note that a sheathed heater may be provided as a heating means in place of the heating coil 3.

The container cover 2 is formed in a bottomed cylindrical shape, and the pot-shaped container 5 is detachably accommodated therein. In the center of the bottom of the container cover 2, a hole 2a for inserting the pan bottom temperature sensor 4 is provided.
The pan bottom temperature sensor 4 is composed of, for example, a thermistor.

  The outer lid 10a is provided with an operation / display section 13 on the upper surface, and a cartridge 12 penetrating to the inner lid 10b is detachably attached. The cartridge 12 includes a steam inlet 12a having a valve that moves up and down according to the steam pressure generated during rice cooking, and a steam outlet 12b that discharges the steam that has passed through the valve of the steam inlet 12a to the outside. Is provided. Further, a moisture content detecting means 15 is arranged inside the outer lid 10a (on the inner lid 10b side).

  The inner lid 10b is attached to the surface of the outer lid 10a on the main body 1 side via a locking member 11. A lid packing 9 made of a sealing material is attached to the peripheral edge of the inner lid 10b to ensure hermeticity with the flange portion 5a formed on the outer periphery of the upper end of the pan-like container 5. Further, an internal temperature sensor 14 made of, for example, a thermistor for detecting the temperature in the pan-like container 5 is attached to the inner lid 10b.

  The control means 8 controls the high frequency current supplied to the heating coil 3 based on the outputs from the pan bottom temperature sensor 4, the operation / display unit 13, the internal temperature sensor 14, and the water absorption judgment means 16, and the overall operation of the rice cooker To control. The control means 8 can be configured by hardware such as a circuit device that realizes the function, or can be configured by an arithmetic device such as a microcomputer or a CPU and software executed thereon.

FIG. 2 is a functional block diagram for explaining the moisture content detecting means 15.
The moisture content detection means 15 according to the first embodiment includes a rice height sensor 21, a reference rice height storage means 22, a rice height comparison means 23, and a moisture content determination means 24. This moisture content detecting means 15 detects the moisture content of rice by utilizing the fact that the higher the moisture content is, the higher the upper surface of the rice stored in the pan-like container 5 is. The rice height comparison means 23 and the moisture content determination means 24 can be configured by hardware such as a circuit device that implements the function, and are executed on an arithmetic device such as a microcomputer or CPU. It can also be configured by software.

The rice height sensor 21 includes a CCD image sensor 211 which is a photographing unit and an illumination unit 212 made of, for example, an LED. As shown in FIG. 1, the rice height sensor 21 is disposed in a state of penetrating the inner lid 10 b so that the CCD image sensor 211 can photograph the inner wall surface of the pan-like container 5. The illumination means 212 is arranged to illuminate the inner wall surface of the pan-like container 5 that is the subject of the CCD image sensor 211, and the CCD image sensor 211 captures a clear image even when the lid 10 is closed. I can do it.
The reference rice height storage means 22 is an image in which a total number of rice in a predetermined unit that can be cooked with a rice cooker is immersed in an appropriate amount of water and placed in a pan-like container 5, and the rice The reference image data when the moisture content is 15, 19, 23, 27, 31, 35, and 39% is stored.

The moisture content W detection process by the moisture content detecting means 15 having such a configuration will be described.
When the moisture content detection means 15 is energized by the control means 8, the illumination means 212 illuminates the inside of the pot-like container 5, and the CCD image sensor 211 cooks rice (water and rice) against the inner wall surface of the pot-like container 5. Shoot.
Next, the rice height comparison means 23 compares the image taken by the rice height sensor 21 with the reference image data stored in the reference rice height storage means 22. By doing so, it is possible to compare the current upper surface height H _{1 of} rice with the upper surface height H _{2 of} rice recorded in the reference image data.
Then, based on the comparison result, the moisture content determination means 24 selects reference image data that is substantially the same as the current upper surface height H ₁ of the rice, and determines the moisture content of the reference image data as the moisture content of the current rice. It is determined that the rate is W.

FIG. 3 is a functional block diagram for explaining the water absorption determining means 16. The water absorption determining means 16 determines the ease of water absorption of rice in the pot-like container 5. The water absorption determination unit 16 according to the first embodiment includes a reference moisture content storage unit 31 and a moisture content comparison unit 32.
The reference moisture content storage means 31 stores moisture content data during rice cooking as reference data. In this Embodiment 1, as a rice cooking process, although a preheating process, a temperature rising process, a main cooking process, and a steaming process are performed in order (it mentions later), after starting each process in the reference | standard moisture content memory | storage means 31, FIG. The moisture content data for each predetermined time is stored as the reference moisture content data.
The moisture content comparison means 32 can be configured by hardware such as a circuit device that realizes the function, or can be configured by an arithmetic device such as a microcomputer or CPU, and software executed thereon. it can.

A process for determining the ease of water absorption by the water absorption determination means 16 having the above configuration will be described.
First, the control means 8 energizes the water absorption judgment means 16 at a predetermined timing. Then, the moisture content detecting means 15 sends information on the detected moisture content W to the water absorption determining means 16. Moreover, the control means 8 sends information indicating which process is the current process in the rice cooking process (that is, any of the preheating process, the temperature raising process, the main cooking process, and the steaming process) to the water absorption determining means 16. Further, the time measuring means 7 sends elapsed time information to the water absorption determining means 16 indicating how much time has elapsed since the process currently being executed has started.
Next, the moisture content comparison means 32 is based on the sent information, and from the reference moisture content storage means 31, the rice cooking process currently being executed is the same, and the elapsed time since the process started. Select the reference moisture content that is the same (including approximate). Then, the detected moisture content W is compared with the selected reference moisture content. When the detected moisture content W is larger than the reference moisture content, it is determined that the rice contained in the pan-like container 5 is easy to absorb water. When the detected moisture content W is equal to or less than the reference moisture content, it is determined that the rice contained in the pan-like container 5 is a rice that is difficult to absorb water.

Next, operation | movement of the rice cooking process of the rice cooker which concerns on this Embodiment 1 is demonstrated.
FIG. 4 is a flowchart illustrating a rice cooking process of the rice cooker according to the first embodiment. Moreover, FIG. 5 is a graph which shows the transition example of the internal temperature of the pot-shaped container 5 in cooking rice, and a pan bottom temperature. FIG. 5 shows how the internal temperature and the pan bottom temperature change as each step of the rice cooking process proceeds. Hereinafter, operation | movement of the rice cooking process of the rice cooker which concerns on Embodiment 1 is demonstrated along FIG. 4, referring FIG. 5 suitably.

  First, a pot-shaped container 5 containing a predetermined amount of rice and water corresponding to the amount of rice is stored in the container cover 2 in the main body 1, the outer lid 10 a is closed, and the rice cooking start switch of the operation / display unit 13 is turned on. If the operation instruction | indication of a rice cooking start is performed by pushing, a rice cooking process will be started.

A rice cooking process starts from a preheating process (S100).
A preheating process is a process of maintaining the to-be-heated thing in the pan-shaped container 5 at the temperature below the gelatinization temperature (60-70 degreeC) of rice (refer FIG. 5), and promoting the water absorption of rice. The longer the preheating step and the higher the temperature of the article to be heated, the higher the water absorption and the higher the moisture content of the rice. It is desirable that the water content be around 30% by the end of the preheating step. Moreover, the activity of the enzyme which exists in rice increases by maintaining the to-be-heated material in the temperature below the gelatinization temperature (60-70 degreeC) of rice, the production | generation of the saccharide | sugar which becomes a sweet component by a starch degrading enzyme, and proteolysis Enzymes promote the production of amino acids that are umami components. Therefore, the longer the preheating process time, the longer the time for the enzyme reaction to occur, and the more flavoring components such as sugar and amino acids lead to an improvement in the taste.

When the preheating step is started, the preheating elapsed time t is measured by the time measuring means 7 (S101), and heating by the heating coil 3 is started (S102).
When the time measuring means 7 detects that the elapsed time t has reached a predetermined time T ₀ which is the initial value of the preheating process time T (S103), the control means 8 drives the moisture content detecting means 15 and described above. Thus, the moisture content W of rice is detected (S104). Based on the detected water content W setting, the water absorption determination means 16 determines the ease of water rice (S105), when it is determined that the water tends to rice, the preheating step time T T ₁ and (S106). The time measuring means 7, the elapsed time t is detected to have reached the pre-heating process time T ₁ (S107), the process proceeds to the temperature increasing step 1 (S200). If it is determined in step S105 that the rice is difficult to absorb water, the preheating process time T is set to T ₂ which is longer than T ₁ (S108). The time measuring means 7, the elapsed time t is detected to have reached the predetermined time T ₂ (S109), the process proceeds to the temperature increasing step 2 (S201).

That is, the preheating process time T is changed according to the ease of water absorption of rice determined in step S105 (S106, S108). As the time of the preheating process becomes longer, the water absorption of the rice proceeds. Therefore, when cooking rice that is easy to absorb water, the excessive water absorption of the rice is suppressed by setting the preheating process time T shorter. Moreover, when cooking rice which is hard to absorb water, water absorption of the rice is promoted by setting the preheating process time T long. By setting the preheating process time T in this way, the water absorption state of rice in the preheating process can be adjusted. The predetermined times T ₀ , T ₁ , and T ₂ are set in advance to values at which the moisture content W of rice becomes a desirable value (for example, about 30%) at the end of the preheating process.

Next, the temperature raising process will be described.
The temperature raising process is a process from the end of the preheating process until the internal temperature sensor 14 detects that the inside of the pan-like container 5 has boiled (see FIG. 5). The smaller the amount of heating in the temperature raising step, the longer the time until boiling is reached, during which water absorption of rice proceeds.

When the temperature raising step 1 is started (S200), the control means 8 power P of the heating coil 3 heats the pot-like container 5 and set to be P ₁ (S202). And if the internal temperature sensor 14 detects a boiling (S203), it will progress to a main cooking process (S300). Further, when the Atsushi Nobori step 2 is started (S201), the control unit 8 heats the pot-like container 5 by setting the power P to a smaller P ₂ than P ₁ (S204). And if the internal temperature sensor 14 detects a boiling (S205), it will progress to a main cooking process (S300).
That is, the electric power P in the temperature rising process is changed according to the ease of water absorption of the rice in the pot-like container 5 determined in step S105, and the electric power P is higher when cooking rice that is hard to absorb water. The time until boiling is lengthened by setting it to be smaller. By setting the power P in this way, the water absorption state of rice can be adjusted in the temperature raising step. Note that the predetermined powers P ₁ and P ₂ are set in advance to values at which the moisture content W of rice becomes a desirable value at the end of the temperature raising step.

Next, the main cooking process will be described. In order to gelatinize the rice, it is necessary to keep the temperature at 98 ° C. or higher for 20 minutes, so in the main cooking process, the temperature is maintained at 98 ° C. or higher (see FIG. 5), and the heated object in the pan-like container 5 does not burn. Heat with such input.
When the main cooking process is completed, the process proceeds to the steaming process (S400).

  In the steaming step (S400), the inside of the pan-like container 5 is not burnt and is kept at 90 ° C. or higher (see FIG. 5). When the steaming process ends, the rice cooking process ends.

As described above, in the first embodiment, the time of the preheating process in the rice cooking process is controlled based on the ease of water absorption of rice. By controlling the time of the preheating process in this way, the moisture content of the rice at the end of the preheating process can be brought close to a desirable value (for example, about 30%), so that the core remains in the cooked rice, or Eliminates the problem of cooking unevenness and realizes stable cooking.
In addition, when it is determined that the rice is easy to absorb water, the preheating process time T is shorter than that of the rice that is difficult to absorb water so that the preheating process is not performed more than necessary. For this reason, while shortening rice cooking time, the power consumption of the heating in a preheating process can be reduced.
When it was judged that the rice was hard to absorb water, the preheating process time was made longer than that of the rice that easily absorbs water. For this reason, while being able to promote water absorption of rice, the time which an enzyme reaction takes place can be lengthened, and good taste rice can be obtained by increasing taste ingredients, such as sugar and an amino acid.
Then, depending on the ease of rice water it is determined in step S105 in FIG. 4, since setting a preheating step time T in T ₁ or T _2, it can be roughly estimate the time required until cooking completion .

  In the temperature raising step, the magnitude of the electric power P is controlled in accordance with the ease of water absorption of rice. Thus, by controlling the magnitude of the electric power P in the temperature raising step, the time until boiling can be controlled, and the water content W of rice at the stage of starting boiling can be adjusted. According to the first embodiment, in addition to adjusting the water absorption state of rice in the preheating step, the water absorption state of rice is further adjusted in the temperature raising step, so the water absorption state of rice at the stage of starting boiling Can be adjusted to a more desirable state, and rice can be cooked more deliciously.

Moreover, in this Embodiment 1, the rice which is a to-be-heated object in the pot-shaped container 5 and the inner wall face of the pot-shaped container 5 are image | photographed during rice cooking operation | movement, the image | photographed image and the reference | standard image data stored beforehand And the moisture content W of the rice in the pan-like container 5 is detected from substantially the same reference image data. The water absorption determining means 16 compares the detected water content W with the reference moisture content data stored in the reference moisture content storage means 31 to facilitate the water absorption of the rice stored in the pan-like container 5. Judging. Thereby, the ease of water absorption of rice can be judged only by detecting the moisture content W of rice once, and heating control in the rice cooking process can be performed.
As described above, there are various characteristics that affect the ease of water absorption of rice, such as varieties, production areas, and new and old rice. For example, it is known that old rice is difficult to absorb water. However, even if it is an old rice, if the rice is cracked rice, the broken portion can easily absorb water, and as a result, it can easily absorb water compared to normal rice. For this reason, when determining the ease of water absorption, for example, if the ease of water absorption is determined only by information set by the user, such as new rice, old rice, and brands of rice, there is a possibility of erroneous determination. . However, according to the first embodiment, the ease of water absorption of the rice is determined based on the moisture content W of the rice in the pan-like container 5, and therefore the ease of water absorption of the rice is determined more accurately. it can.

  Further, the moisture content detecting means 15 according to the first embodiment detects the moisture content W of rice using the image taken by the CCD image sensor 211. For this reason, it is hygienic because the moisture content W can be detected in a non-contact manner with respect to the object to be heated. As a conventional method for measuring the moisture content of rice, there is a method of heating the rice itself to evaporate water and calculating the moisture content from the weight change before and after heating. If such a conventional method is taken, the rice used for the moisture content measurement cannot be eaten and the rice is wasted, but according to the moisture content detecting means 15 according to the first embodiment, There is no waste of rice.

The water absorption determining means 16 may determine from the amount of change in the moisture content W detected by the moisture content detecting means 15 every predetermined time, instead of determining the ease of water absorption of rice by the above-described method. For example, when the time measuring means 7 measures a predetermined time T ₀ that is an initial value of the preheating process time T, the moisture content detecting means 15 detects the moisture content W, and the time measuring means 7 detects the predetermined time T ₀ for 5 minutes. When the latter is measured, the moisture content detecting means 15 detects the moisture content W ′. Since it can be said that the greater the difference between the moisture content W and the moisture content W ′, the more water is absorbed, the water absorption determining means 16 performs the water absorption of rice based on the difference (change amount) between the moisture content W and the moisture content W ′. Easiness can be judged. By doing in this way, the judgment precision of the ease of water absorption of the rice by the water absorption judgment means 16 can be improved.

Embodiment 2. FIG.
In the first embodiment described above, the water absorption determining means 16 determines the ease of water absorption of rice from the information on the water content W detected by the water content detection means 15. In the second embodiment, the fact that rice with a high protein content has the property of being difficult to absorb water is used to detect the protein content of rice and to absorb the water of the rice based on the detected protein content of rice. An example of determining ease will be described.
In the second embodiment, differences from the first embodiment will be mainly described, and the same or corresponding parts as those in FIGS. 1 to 4 described above are denoted by the same reference numerals.

FIG. 6 is a schematic cross-sectional view illustrating the configuration of the rice cooker according to the second embodiment.
In FIG. 6, the water absorption determining unit 16 </ b> A includes a protein amount measuring unit 33 that can measure the protein amount of rice and a protein amount comparing unit 34.
The protein amount measuring means 33 is a device that measures the amount of protein by a near-infrared spectroscopic method. For example, the protein amount measuring unit 33 includes a light source that emits light in the near-infrared region, and irradiates the rice with light from the light source. The amount of protein in rice is measured based on the reflected or transmitted light. In addition, the structure of the protein amount measuring means 33 is not limited to this, Arbitrary structures and methods can be used. Information on the protein amount detected by the protein amount measuring unit 33 is sent to the protein amount comparing unit 34.
The protein amount comparison unit 34 determines that the rice in the pan-like container 5 is water-absorbing rice if the protein amount detected by the protein amount measurement unit 33 is equal to or less than a predetermined value, and exceeds the predetermined value. If so, it is judged that the rice is difficult to absorb water.

  In the vicinity of the bottom of the container cover 2, a hole 2b for inserting and installing the protein amount measuring means 33 is provided. The portion near the bottom of the pan-like container 5 and exposed to at least light irradiated from the protein amount measuring means 33 is composed of a material that transmits light in the near infrared region, for example, quartz glass 5b. The protein amount measuring means 33 irradiates the rice in the pot-shaped container 5 with light through the quartz glass 5b, and determines the protein amount of the rice in the pot-shaped container 5 based on the reflected light or transmitted light from the rice. taking measurement.

Next, operation | movement of the rice cooking process of the rice cooker which concerns on this Embodiment 2 is demonstrated. FIG. 7 is a flowchart showing a rice cooking process of the rice cooker according to the second embodiment.
First, a predetermined amount of rice and a pot-like container 5 containing water corresponding to the amount of rice are stored in the container cover 2 in the main body 1, the outer lid 10 a is closed, and the rice cooking start switch ( Pressing (not shown) starts the rice cooking operation.

When the rice cooking operation is started, first, the preheating process is started (S100b), and the elapsed time t of the preheating process is measured by the time measuring means 7 (S111).
The control means 8 drives the protein amount measuring means 33 to measure the amount of rice protein in the pan-like container 5, and further drives the water absorption determining means 16A to absorb the water based on the amount of rice protein. Ease is judged (S112b).
If it is determined in step S112b that the rice is likely to absorb water, a predetermined temperature C1 is set as a heating temperature in the preheating process (hereinafter referred to as preheating process temperature C), and heating is started (S113).
When the time measuring means 7 detects that the elapsed time t has reached a predetermined time T ₀ which is the initial value of the preheating process time T (S114), the control means 8 drives the moisture content detecting means 15 to As described in the first embodiment, the moisture content W of rice is detected (S115). And it is determined whether the moisture content W of rice is smaller than the predetermined moisture content W _a (S115a), and when it is determined that the moisture content W is smaller than the predetermined moisture content W _a , the elapsed time measuring means (FIG. (Not shown) starts measuring the predetermined elapsed time t2 (S115b). During this time, heating in the preheating step is continued. Then, it is determined whether the elapsed time t2 has reached a predetermined unit time T ₃ (S115c), the predetermined unit time T ₃ detects the water content W after the lapse (S115). That is, the moisture content W of rice is detected every predetermined unit time T ₃ . Then, heating in the preheating step is continued until the moisture content W of the rice reaches _a predetermined moisture content W _a , and when it is determined that the moisture content W has reached the predetermined moisture content W _a (S115a), the temperature raising step 1 (S200).

If it is determined in step S112b that the rice is difficult to absorb water, the water absorption of the rice promotes the water absorption by utilizing the fact that the water temperature is higher, so the preheating process temperature C is set to a temperature higher than the predetermined temperature C1. A predetermined temperature C2 is set, and heating is started (S116).
When the time measuring means 7 detects that the elapsed time t has reached a predetermined time T ₀ which is the initial value of the preheating process time T (S117), the control means 8 drives the moisture content detecting means 15 and described above. Thus, the moisture content W of rice is detected (S118). Then, it is determined whether the moisture content W of the rice is smaller than the predetermined moisture content W _a (S118a). If it is determined that the moisture content W is smaller than the predetermined moisture content W _a , the elapsed time measuring means (FIG. (Not shown) starts measuring the predetermined elapsed time t2 (S118b). During this time, heating in the preheating step is continued. Then, it is determined whether the elapsed time t2 has reached a predetermined unit time T ₃ (S118c), the predetermined unit time T ₃ detects the water content W after the lapse (S118). Then, heating in the preheating step is continued until the moisture content W of the rice reaches _a predetermined moisture content W _a , and if it is determined that the moisture content W has reached the predetermined moisture content W _a (S118a), the temperature raising step 2 (S201).
The steps from the temperature raising step 1 in step S200 to the end of cooking are the same as those in the first embodiment from the temperature raising step 2 in step S201 to the end of cooking.
The predetermined times T ₀ and T ₃ and the temperatures C1 and C2 are set in advance to values at which the moisture content W of rice becomes a desirable value (for example, about 30%) at the end of the preheating process.

As described above, in the second embodiment, the heating temperature in the preheating process is controlled based on the ease of water absorption of rice. Since the water absorption of rice can be promoted by increasing the heating temperature in the preheating step, the moisture content of the rice at the end of the preheating step is preferably set by controlling the heating temperature in the preheating step based on the ease of water absorption in the rice ( For example, about 30%).
In addition, when it is determined that the rice does not easily absorb water, the heating temperature in the preheating process is set higher than that of the rice that easily absorbs water. For this reason, the water absorption of rice can be promoted, the time required for the moisture content W of the rice to reach a desired value (for example, about 30%) at the end of the preheating process can be shortened, and the rice cooking time can be shortened. become.

In addition, if the heating temperature in the preheating step is increased, the water absorption of rice may proceed excessively. However, since the moisture content W is detected every predetermined time in the second embodiment, the water absorption of the rice is excessive. Proceeding can be suppressed. For this reason, the water absorption of rice at the end of the preheating step can be made almost constant.
In addition, the preheating process time is controlled based not only on the ease of water absorption of rice, but also on the detected water content W, so that the state of the cooked rice can be further stabilized and the user can use delicious rice. Can be provided.

  Moreover, in this Embodiment 2, the ease of water absorption was judged from the protein amount. By measuring the amount of protein contained in the rice before the start of heating and determining the ease of water absorption, the ease of water absorption of the rice can be determined before the start of heating. The preheating step can be performed at a heating temperature and time suitable for the above.

  In addition, in the preheating process of FIG. 7, it is also possible to perform a process that does not detect the moisture content W. That is, steps S115, S115a to S115c, S118, and S118a to S118c in FIG. 7 may be omitted, and only the heating temperature of the preheating process may be controlled based on the ease of water absorption of rice. Since the water absorption of rice can be promoted or suppressed by increasing or decreasing the heating temperature in the preheating step, it is possible to adjust the moisture content W of the rice at the end of the preheating step. Thereby, since it is not necessary to provide the moisture content detection means 15, it becomes cost reduction and can make the magnitude | size of the whole rice cooker compact. Further, the control process by the control means 8 can be simplified.

  Moreover, you may control the preheating process of FIG. 7 using the water absorption judgment means 16 demonstrated in Embodiment 1. FIG. That is, the ease of water absorption of rice may be determined based on the moisture content W, and the heating temperature in the preheating step may be controlled based on the ease of water absorption of the rice.

  In the first and second embodiments described above, the moisture content detection means 15 is configured using the CCD image sensor 211 and the illumination means 212, and the upper surface height of the rice is measured using an image photographed by the CCD image sensor 211. Thus, it has been explained that the moisture content W is detected. However, the structure of the moisture content detection means 15 is not limited to this. For example, a measuring device that detects rice by touching the measuring means, such as an electric resistance moisture meter, may be used as the moisture content detecting means 15. In this case, since the rice itself is directly analyzed, the detection accuracy can be improved as compared with estimating the moisture content from the image.

  Moreover, in Embodiment 1 and Embodiment 2 mentioned above, based on the ease of water absorption of rice, any one or more of the time of the preheating process, the heating temperature of the preheating process, and the electric power of the heating process is used. By controlling, the optimal rice cooking sequence is executed, but if there is information such as the amount of rice cooking and the water ratio (ratio of the amount of water relative to the amount of rice), a better rice cooking sequence can be executed that also includes those information. . Therefore, when the rice cooker 100 includes a weight sensor and a water level sensor, detects the amount of rice and the amount of water, and obtains the amount of rice cooking and the water addition ratio from the information, the state of the cooked rice can be further stabilized. Can provide delicious rice to the user.

  Moreover, in Embodiment 1 and Embodiment 2 mentioned above, although describing as performing a preheating process in a rice cooking process, it is also possible not to implement a preheating process. That is, rice can be cooked even if the heating step is performed immediately after the start of cooking.

  DESCRIPTION OF SYMBOLS 1 Main body, 2 Container cover, 2a hole part, 2b hole part, 3 Heating coil, 4 Pan bottom temperature sensor, 5 Pot-shaped container, 5a Flange part, 5b Quartz glass, 6 Hinge part, 7 Time measuring means, 8 Control means, 9 lid packing, 10 lid, 10a outer lid, 10b inner lid, 11 locking material, 12 cartridge, 12a steam inlet, 12b steam outlet, 13 operation / display section, 14 internal temperature sensor, 15 moisture content detecting means , 16 Water absorption determination means, 16A Water absorption determination means, 21 Rice height sensor, 22 Reference rice height storage means, 23 Rice height comparison means, 24 Water content determination means, 31 Reference water content storage means, 32 Water content comparison means 33 protein amount measuring means, 34 protein amount comparing means, 100 rice cooker, 211 CCD image sensor, 212 illumination means.

Claims (4)

The body,
A pot-shaped container accommodated in the main body;
A lid covering the opening of the pan-like container;
Heating means for heating the pan-like container;
Control means for controlling the heating means to perform a rice cooking step including a preheating step and a temperature raising step;
A moisture content detecting means for detecting the moisture content of rice put together with water in the pan-like container;
Water absorption determination means for determining the ease of water absorption of the rice based on the change in the moisture content of the rice in the pan-like container detected by the moisture content detection means ,
The said control means controls the time of the said preheating process according to the ease of water absorption of the rice judged by the said water absorption judgment means, The rice cooker characterized by the above-mentioned. Before SL control means, depending on the ease of rice is determined water by the water determination means according to claim 1, wherein the controlling the heating temperature at the time and the preheating step of the preheating step of rice cooker. Before SL control means includes wherein depending on the ease of rice is determined water by water absorption determining means, for controlling the power supplied to the heating unit in time and the heating step of the preheating step The rice cooker according to claim 1 . When that rice water content of the pot-shaped container has reached a predetermined moisture content during the previous SL preheating step is the water content detection means for detecting, said control means, characterized in that the process proceeds to the heating step cooker according to any one of claims 1 to 3,.

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