JP2012152635A - Rice cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rice cooker that can stably and deliciously cook rice without causing a trouble to a user.SOLUTION: The rice cooker includes: a body 1; a pot-shaped container 5 stored in the body 1; a lid body 10 for covering an opening part of the pot-shaped container 5; a heating coil 3 for heating the pot-shaped container 5; control means 8 for driving and controlling the heating coil 3 to perform a rice cooking step including a preheating step and a temperature-raising step; and moisture content detection means 15 for detecting the moisture content of rice. The moisture content detection means 15 detects the moisture content of the rice at least one time while boiling is detected in the temperature-raising step after the lid is closed. The control means 8 adjusts at least one of a heating temperature in the preheating step and power supply in the temperature-raising step according to the detected moisture content of the rice by the moisture content detection means 15.

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 state of preservation, 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, conventionally, the “control means 3 has a water absorption step of absorbing water into the rice after the start of cooking using the rice soaking time input from the soaking time measuring means 5 and the rice production area selected by the production area selection means 7. A rice cooker that "adjusts the time of" has been proposed (see, for example, Patent Document 1).

JP 2007-75322 A (summary, FIG. 1)

  However, in the rice cooker described in Patent Document 1, it takes time for the user to bother selecting the rice production area, and when the user does not know the rice production area, the time of the water absorption process is optimally adjusted. I couldn't.

  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. A control means for controlling and performing a rice cooking process including a preheating process and a temperature raising process; and a moisture content detecting means for detecting the moisture content of the rice, the moisture content detecting means after the lid is closed The water content of the rice is detected at least once before the boiling is detected in the temperature raising step, and the control means determines whether the water content in the preheating step is in accordance with the water content of the rice detected by the water content detection means. At least one of the heating temperature and the electric power in the temperature raising step is adjusted.

According to the present invention, the moisture content detecting means detects the moisture content of the rice at least once after the lid is closed until the boiling is detected in the temperature raising step, and the control means is the moisture content detecting means. At least one of the heating temperature in the preheating step and the electric power in the temperature raising step is adjusted according to the moisture content of the rice detected by. For this reason, it can suppress that a core remains in cooked cooked rice or cooking unevenness arises.
In addition, since the moisture content detection means detects the moisture content of rice, information on characteristics that affect the ease of rice absorption (for example, varieties, production areas, distinction between new rice and old rice, etc.) is pre- There is no need to set it by the user. 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 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 flowchart which shows the operation | movement of the rice cooking process 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 3. FIG. It is a flowchart which shows the operation | movement of the rice cooking process of the rice cooker which concerns on Embodiment 4. FIG. It is a block block diagram of the moisture content detection means of the rice cooker which concerns on Embodiment 5. FIG. It is a cross-sectional schematic diagram which shows the state of the cooked rice in the pot-shaped container which concerns on Embodiment 5. 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, and FIG. 2 is a block configuration diagram of the moisture content detecting means in the rice cooker of the first embodiment.

  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 freely opened and closed, and a control means 8. 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 overall operation of the rice cooker in addition to controlling the high-frequency current to be supplied to the heating coil 3 based on the outputs from the pan bottom temperature sensor 4, the operation / display unit 13, and the moisture content detection means 15. 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 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 so as 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 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.

Next, operation | movement of the rice cooking process of the rice cooker which concerns on this Embodiment 1 is demonstrated.
FIG. 3 is a flowchart illustrating a rice cooking process of the rice cooker according to the first embodiment. Moreover, FIG. 4 is a graph which shows the transition example of the internal temperature and pan bottom temperature of the pan-shaped container 5 during rice cooking. FIG. 4 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. 3, referring FIG. 4 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. As shown in FIG. 3 and FIG. 4, the rice cooking process of the rice cooker according to the first embodiment includes a preheating process (S100), a temperature raising process (S200), a main cooking process (S300), and a steaming process (S400). Consists of.

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. 4), 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 sweetness component by a starch degrading enzyme, and protein decomposition 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, a preheating elapsed time t is measured by a time measuring means (not shown) (S101), and heating is started (S102).
When it is detected by the time measuring means 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 as described above. Then, the moisture content W of the rice is detected (S104).
Then, it is determined whether rice moisture content W is less than a predetermined water content W ₁ (S105), if the water content W is less than a predetermined water content W ₁ is less rice to cooking is water absorption proceeds rice Therefore, the preheating process time T is set to T ₁ (S106). The time measuring means, 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 (S200). Further, in step S105, if the water content W detected by the water content detecting means 15 is determined to be a predetermined water content W ₁ or more, rice to cooking, it is determined that the water absorption is proceeds easily rice The preheating process time T is set to T ₂ which is shorter than T ₁ (S108). The time measuring means, the elapsed time t is detected to have reached the predetermined time T ₂ (S109), the process proceeds to the temperature increasing step (S200).
That is, the preheating process time T is changed according to the moisture content W of rice in step S105, and the preheating process time is set longer when the moisture content W is small. By setting the preheating process time T in this way, the water content W of rice in the preheating process can be adjusted. The predetermined moisture content W ₁ and the times T ₀ , T ₁ , T ₂ are set in advance so that the moisture content W of rice becomes a desirable value (for example, about 30%) at the end of the preheating process. ing.

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 pot-like container 5 has boiled (see FIG. 4). 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 heating process is started (S200), the water content detecting means 15 detects the water content W of rice (S201), determines whether the water content W is less than a predetermined water content W ₂ (S202).
When the moisture content W of rice is smaller than the predetermined moisture content W ₂ , the control means 8 heats the pan-like container 5 by setting the power P of the heating coil 3 to P ₁ in the temperature raising step (S203). . And if the internal temperature sensor 14 detects a boiling (S204), it will progress to a main cooking process (S300). Further, in step S202, when rice moisture content W is a predetermined water content W ₂ or more, the control unit 8 is a pot-like container 5 by setting the power P of the heated process large P ₂ than P ₁ Heat (S205). And if the internal temperature sensor 14 detects boiling (S206), it will progress to a main cooking process (S300).
That is, the electric power P in the temperature raising process is changed according to the water content W of rice in step S202, and the electric power P is set to be smaller when the water content W of rice is small until boiling. The time is long. By setting the power P in this way, the moisture content W of rice can be adjusted in the temperature raising step. Note that the predetermined water content W ₂ and the electric powers P ₁ and P ₂ are set in advance to values at which the water content W of rice becomes a desirable value at the end of the heating process.

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 the main cooking process maintains 98 ° C. or higher (see FIG. 4), 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. 4). When the steaming process ends, the rice cooking process ends.

As described above, in the first embodiment, during the rice cooking operation, the rice that is the object to be heated in the pan-like container 5 and the inner wall surface of the pan-like container 5 are photographed, and the photographed image and the reference stored in advance are recorded. Compared with the image data, the moisture content W of the rice in the pan-like container 5 is determined from substantially the same reference image data. Thereby, it becomes possible to perform the heating control in the rice cooking process according to the moisture content W of the rice, that is, the water absorption state of the rice.
And according to the moisture content W of the detected rice, it was made to control the time of the preheating process in a rice cooking process. By controlling the time of the preheating process in this way, the water absorption state of the rice at the stage of starting boiling can be adjusted, so the problem that the core remains in the cooked cooked rice, or cooking unevenness can be solved, Stable cooking can be realized.

Moreover, in this Embodiment 1, when it was judged that it is the rice which water absorption tends to advance, it did not perform a preheating process more than necessary. For this reason, while shortening rice cooking time, the power consumption of the heating in a preheating process can be reduced.
In addition, when it was judged that the rice is difficult to absorb water, the preheating process time was extended. For this reason, the time for the enzyme reaction to take place can be lengthened, and a good-tasting rice can be obtained by increasing the taste components such as sugars and amino acids.
Then, depending on the value of the water content W detected in the step S140 of FIG. 3, since setting a preheating step time T in T ₁ or T _2, can be roughly estimate the time required until cooking completion.

  Further, the water content W is detected in the temperature raising step, and the magnitude of the electric power P is controlled in accordance with the water content W. 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. For this reason, the problem that the core remains in the cooked cooked rice or the cooking unevenness can be solved, and stable cooking can be realized. Furthermore, according to this Embodiment 1, in addition to adjusting the water absorption state of the rice in the preheating step, the water absorption state of the rice is further adjusted in the temperature raising step, so that the rice at the stage of starting boiling The water absorption state can be adjusted to a more desirable state, and rice can be cooked more deliciously.

  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.

Embodiment 2. FIG.
In the first embodiment described above, T ₁ or T ₂ is set as the preheating process time T in accordance with the moisture content W detected by the moisture content detecting means 15 during the preheating process. In the second embodiment, the preheating process is continued until the moisture content W reaches _a desired predetermined moisture content W _a (for example, around 30%) in the preheating process.
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 3 described above are denoted by the same reference numerals.

FIG. 5 is a flowchart showing the rice cooking process of the rice cooker according to the second embodiment.
When the rice cooking start switch of the operation / display unit 13 is pressed to start the rice cooking process, the preheating process is first started (S100a). When the preheating step is started, a preheating elapsed time t is measured by a time measuring means (not shown) (S101), and heating is started (S102).
When it is detected by the time measuring means 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 as described above. Then, the moisture content W of the rice is detected (S104).
Then, it is determined whether or not the moisture content W of the rice is smaller than the predetermined moisture content W _a (S104a). If it is determined that the moisture content W is smaller than the predetermined moisture content W _a , the elapsed time measuring means is predetermined. The measurement of the elapsed time t2 is started (S104b). 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 (S104c), the predetermined unit time T ₃ detects the water content W after the lapse (S104). 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 (S104a), the temperature raising step Proceed to (S200a).

When the water content W reaches _a predetermined water content W _a , the water has been absorbed to a just good state at this stage, so in the temperature raising step of Step S200a, it is heated with a predetermined power P3 (S203a). And if the internal temperature sensor 14 detects a boiling (S204a), it will progress to a main cooking process (S300). The process from the main cooking process of step S300 to the end of cooking is the same as in the first embodiment.

As described above, in the second embodiment, the moisture content W of rice is detected every predetermined time, and the preheating process is continued until the moisture content W reaches the predetermined moisture content W _a . For this reason, the water absorption amount of the rice at the end of the preheating step can be realized in a constant state without excess or deficiency, and the state of the cooked cooked rice can be stabilized. Therefore, even when cooking rice with a different ease of water absorption, the rice cooking control suitable for the rice is performed without bothering the user every time the rice is cooked. You can cook.

Embodiment 3 FIG.
In the first embodiment described above, reference image data having a predetermined moisture content is stored in advance in the reference rice height storage means 22, and the reference image data is compared with an actual image taken by the rice height sensor 21. The water content W of rice was judged. In this Embodiment 3, the rice height sensor 21 images the cooked rice in the pan-like container 5 before cooking, and the captured image data is stored as the reference initial state by the reference rice height storage means 22.
In the third embodiment, differences from the first embodiment will be mainly described, and the same or corresponding parts as those in FIGS. 1 to 3 described above are denoted by the same reference numerals.

FIG. 6 is a flowchart showing the rice cooking process of the rice cooker according to the third 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. As shown in FIG. 6, the rice cooking process of the rice cooker which concerns on this Embodiment 3 is step S501, step S502, a preheating process (S100b), a temperature rising process (S200), a main cooking process (S300), and a steaming process. (S400).

  When the rice cooking operation is started, the control means 8 drives the rice height sensor 21 to photograph the cooked rice (rice and water) against the inner wall surface of the pan-like container 5 (S501). And the reference | standard rice height memory | storage means 22 memorize | stores the image | photographed image data as an initial state (S502), and progresses to a preheating process (S100b).

When the preheating step is started, the elapsed time is measured by a time measuring means (not shown) (S101), and heating is started (S102).
When the time measuring means 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 rice height sensor 21 to make a pot-shaped container. The cooked rice (rice and water) against the inner wall surface of No. 5 is photographed (S104d). The rice height comparison means 23 outputs the image data when the elapsed time t = predetermined time T ₀ output from the rice height sensor 21 and the image data stored as the reference initial state by the reference rice height storage means 22. In comparison, the moisture content determination means 24 detects the moisture content W from the change in the upper surface height of the rice based on the comparison result (S104e).

  Here, the moisture content detection process in step S104e will be described. In the case of general rice, the water content before washing is around 15%, but after washing the rice, an appropriate amount of water is put into the pot-like container 5 and the pot-like container 5 is stored in the container cover 2 in the main body 1. In the meantime, the moisture content of rice will be approximately 20%. For this reason, it is assumed that the image stored by the reference rice height storage means 22 as an initial state (S502) is a state in which the moisture content of rice is 20%. Then, if the top surface height of rice in the image photographed in step 140d has hardly changed compared to the top surface height in the initial state (S501), it is determined that the moisture content of rice remains 20%. The higher the top surface height of rice in the image photographed in step 104d is, the higher the water absorption rate and the higher the water content, so the water content W is determined from the rate of change in the top surface height of the rice. Is detected.

  When the moisture content W is detected in step S104e, the process proceeds to step S105. The process from step S105 to the end of cooking is the same as in the first embodiment.

  As mentioned above, in this Embodiment 3, the image of the rice cooker of an initial state is image | photographed before the heating start, the image is memorize | stored as an initial state, the image memorize | stored as this initial state, and the image of the current rice cooker And the moisture content W of the rice in the pan-like container 5 was detected. Since the moisture content W is detected using the actual cooked rice that is the heating target, the detection accuracy of the moisture content W can be increased. For example, even when the rice accommodated in the pan-like container 5 is partially biased, the state before the preheating process is stored as the initial state, and the moisture content W is determined from the change rate of the top surface height of the rice. Therefore, the moisture content W can be detected with stable accuracy regardless of the state of accommodation of the cooked rice.

  Moreover, the detection accuracy of the moisture content W can be increased regardless of the amount of rice. That is, when the rice amount is Rx and the moisture content is Wx, the top surface height of the rice is H, and when the rice amount is Ry (Rx <Ry) and the moisture content is Wy (Wx> Wy), the top surface of the rice When the height is H, it is difficult to determine whether the moisture content is Wx or Wy only by the information of the upper surface height H of the rice. However, in this Embodiment 3, since the image of the cooked rice in the initial state before heating is taken and the change rate of the upper surface height of the rice is detected, the change rate of the upper surface height of the rice even in the above case If is large, the moisture content is Wx, and if the change rate of the top surface height of rice is small, the moisture content can be determined to be Wy.

In the third embodiment, when the rice cooking start switch is pressed and a rice cooking start operation instruction is made, rice cooking is started and the rice height sensor 21 is driven to take a picture of the cooked rice. The reference rice height storage means 22 is stored as the reference initial state. However, a lid opening / closing detection sensor (not shown) is provided in the main body 1 and when the lid opening / closing detection sensor (for example, touch sensor) detects that the outer lid 10a is closed, the rice height sensor 21 is driven. The cooked rice may be photographed, and the image data stored in the reference rice height storage unit 22 may be stored as a reference initial state.
For example, after storing a predetermined amount of rice and a pot-like container 5 containing water corresponding to the amount of rice in the container cover 2 in the main body 1, the outer lid 10a was closed without pressing the rice cooking start switch immediately. Sometimes left unattended. In such a case, since the water absorption of the rice proceeds even while it is left, when the rice cooking switch is pushed after it is left and the rice height sensor takes a picture of the initial state, the moisture content of the rice is 20 as described above. % May be greatly exceeded. In Embodiment 3, since the moisture content W is detected on the assumption that the rice in the initial state photographed by the rice height sensor 21 before starting heating has a moisture content of 20%, the actual moisture content of the rice in the initial state is detected. If the deviation is larger than 20%, the value of the moisture content W to be detected also increases. Therefore, by automatically photographing the cooked rice in the initial state when the outer lid 10a is closed, the influence of water absorption during leaving can be suppressed as much as possible, and the detection accuracy of the moisture content W can be improved.

Embodiment 4 FIG.
In the fourth embodiment, a reserved rice cooking mode is provided, and when the reservation setting is determined, the rice height sensor 21 images the cooked rice in the pan-like container 5 before cooking rice, and the captured image data is used as the reference rice. An example in which the height storage unit 22 stores the reference initial state will be described. Also, the temperature in the preheating process is adjusted according to the water absorption state of the rice.
In the fourth embodiment, differences from the first embodiment will be mainly described, and the same or corresponding parts as those in FIGS. 1 to 3 are denoted by the same reference numerals.

  The control means 8 of the rice cooker according to the fourth embodiment can be operated in the reserved rice cooking mode. The reserved rice cooking mode is a mode in which the rice cooking operation is terminated at the cooking time preset by the user, and is in a standby state from the time when the reserved rice cooking is set until the start of the rice cooking process.

  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, and the outer lid 10a is closed. And the reservation cooking rice is set. Specifically, the reservation setting button on the operation / display unit 13 is pressed to select the scheduled end time of reserved rice cooking, and the reservation setting determination button is pressed. Thus, it is determined to perform the operation in the reserved rice cooking mode.

  FIG. 7 is a flowchart showing a rice cooking process by the rice cooker according to the fourth embodiment. As shown in FIG. 7, the rice cooking process of the rice cooker according to the fourth embodiment includes steps S601 to S605, a preheating process (S110), a temperature raising process (S200), a main cooking process (S300), and a steaming process. (S400).

  When the reservation rice cooking mode is determined, the control means 8 drives the rice height sensor 21 to photograph the cooked rice (rice and water) against the inner wall surface of the pan-like container 5 (S601). And the reference | standard rice height memory | storage means 22 memorize | stores the image | photographed image data as an initial state (S602). The control means 8 calculates the reservation standby time Y1 until cooking of rice starts from the reservation setting information input from the operation / display unit 13 (S603), and starts measuring the elapsed time y (S604). If it is determined that the elapsed time y has reached the reserved standby time Y1 (S605), the process proceeds to the preheating step of step S110.

When the preheating process is started, measurement of the elapsed time t is started by a time measuring means (not shown) (S111). The control means 8 drives the rice height sensor 21 to photograph the cooked rice (rice and water) against the background of the inner wall surface of the pan-like container 5 (S112).
The rice height comparing means 23 compares the image data taken by the rice height sensor 21 in step S112 with the image data stored as the reference initial state by the reference rice height storage means 22 in step S602, and the moisture content The judging means 24 detects the moisture content W from the change in the upper surface height of the rice based on this comparison result (S113).
When the water content W is determined to be smaller than the predetermined water content W _1, as the rice used water is insufficient, the heating temperature in the preheating step (hereinafter, referred to as preheating step Temperature C) as A predetermined temperature C1 is set and heating is started (S115). The time measuring means, the elapsed time t is detected to have reached the predetermined time T ₄ (S116), the process proceeds to the temperature increasing step (S200).
Further, when the detected water content W by the water content detecting means 15 is a predetermined water content W ₁ or more (S114), the rice used to prevent excessive water absorption by determining the water absorption is sufficient The preheating process temperature C is set to a predetermined temperature C2 that is lower than the predetermined temperature C1, and heating is started (S117). The time measuring means, the preheating process time t is detected to have reached the predetermined time T ₄ (S118), the process proceeds to the temperature increasing step (S200).
Note that the predetermined moisture content W ₁ , time T ₄ , and temperatures C 1 and C 2 are set in advance so that the moisture content W of rice becomes a desirable value (for example, about 30%) at the end of the preheating process. Yes.
The process from step S200 to the end of cooking is the same as in the first embodiment.

  As described above, the fourth embodiment has a reserved rice cooking mode, and when the operation in the reserved rice cooking mode is determined, the cooked rice (rice and water) against the inner wall surface of the pot-like container 5 is photographed. The reference rice height storage means 22 stores the captured image data as an initial state, and the moisture content W is detected before heating. Since the water absorption of rice proceeds during the reservation, it is possible to carry out a preheating process according to the water absorption state by determining how much the water absorption has advanced during the reservation.

  In addition, the heating temperature in the preheating step is adjusted depending on whether the moisture content W of the rice at the start of the preheating step is equal to or higher than a predetermined value. Since the water absorption proceeds as the heating temperature increases, the water absorption degree of the rice can be adjusted without changing the preheating process time by adjusting the heating temperature in the preheating process. In the case of reserved rice cooking, it is necessary to calculate the time required for the rice cooking process as accurately as possible in order to finish cooking at the scheduled rice cooking end time. As in the fourth embodiment, the time required for the rice cooking process can be predicted more accurately by making the preheating process time constant and controlling the heating temperature in the preheating process.

Embodiment 5 FIG.
In the fifth embodiment, an example in which the moisture content W of rice is detected based on the height of the upper surface of the rice and the height of the water surface will be described.
In the fifth embodiment, the characteristic water content W detection process will be described focusing on the differences from the first embodiment.

  FIG. 8 is a functional block diagram for explaining the moisture content detection means 15A according to the fifth embodiment. The moisture content detection unit 15A according to the fifth embodiment includes a rice / water height sensor 21A, a reference height storage unit 22A, a height comparison unit 23A, and a moisture content determination unit 24A.

The rice / water height sensor 21A corresponds to the water height sensor and the rice height sensor of the present invention. Similar to the first embodiment, the CCD image sensor 211, which is a photographing means, and an illumination means comprising, for example, LEDs. 212.
The reference height storage means 22A 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 An image showing the height of rice (amount of rice) and a reference image showing the height of water (amount of water) when the water content is 15, 19, 23, 27, 31, 35, 39%, respectively. Data is stored.

The moisture content W detection process by the moisture content detecting means 15A having such a configuration will be described.
When the moisture content detection means 15A is energized by the control means 8, the illumination means 212 illuminates the inside of the pan-like container 5, and the CCD image sensor 211 cooks rice with the inner wall surface of the pan-like container 5 as the background (rice and water). Shoot.
Then, the height comparison unit 23A compares the image captured by the rice / water height sensor 21 with the reference image data stored in the reference height storage unit 22A, so that the current upper surface height Ha of the rice is obtained. And the upper surface height Hb of the rice recorded in the reference image data, and the current water surface height ha and the water surface height hb recorded in the reference image data are compared. Then, based on these comparison results, the moisture content determination means 24A selects reference image data having the same top surface height Hb of the current rice and the same water surface height hb. The moisture content of the reference image data is determined to be the current moisture content W of rice.

Next, operation | movement of the rice cooking process of the rice cooker which concerns on this Embodiment 5 is demonstrated. The operation of the rice cooking process is the same as that in FIG. 3 described above, and will be described with reference to FIG.
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 of the operation / display unit 13 is turned on. When pressed, the rice cooking process is started. When cooking is started, a preheating process is started (S100).
When the preheating step is started, a preheating elapsed time t is measured by a time measuring means (not shown) (S101), and heating is started (S102).
When it is detected by the time measuring means 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 15A to The rate W is detected (S104). The detection process of the moisture content W is as described above.
After detecting the moisture content W, the process from step S105 to the end of rice cooking is the same as in the first embodiment.

As described above, in the fifth embodiment, the moisture content W of rice in the pan-like container 5 is determined based on the upper surface height and the water surface height of rice. For this reason, the detection accuracy of the moisture content W can be increased.
For example, as shown in FIG. 9A, when the amount of rice is R _x and the moisture content is W _x , the top surface height of the rice is H, and as shown in FIG. 9B, the amount of rice is R _y (R _x <R _In some cases, the upper surface height of rice is H when the water content is W _y (W _x > W _y ). In such a case, it is difficult to determine whether the moisture content of the rice is W _x or W _y only by information on the upper surface height H of the rice. However, the water content can be determined by using the water surface height h together with the determination of the water content as in the fifth embodiment. In the case of the example of FIG. 9, since water absorption / swelling of rice is progressing in FIG. 9A, the height h _{1 of the} water surface is small, and in FIG. 9B, water absorption hardly progresses, so the height h _{2 of the} water surface is large. The water content can be detected more accurately by looking at the water surface height as well as the top surface height of rice.

  In addition, the detection process of the moisture content W demonstrated in this Embodiment 5 can also be combined with Embodiment 2-4, and the same effect can be acquired.

  In the first to fifth 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 rice is measured using the image taken 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.

  DESCRIPTION OF SYMBOLS 1 Main body, 2 Container cover, 2a Hole part, 3 Heating coil, 4 Pan bottom temperature sensor, 5 Pan-shaped container, 5a Flange part, 6 Hinge part, 8 Control means, 9 Cover packing, 10 Cover body, 10a Outer cover, 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 detection means, 21 Rice height sensor, 211 CCD image sensor, 212 Illumination means, 22 reference rice height storage means, 23 rice height comparison means, 24 moisture content determination means, 15A moisture content detection means, 21A rice / water height sensor, 22A reference height storage means, 23A height comparison means 24A Moisture content judgment means, 100 rice cooker.

Claims (2)

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,
The moisture content detecting means detects the moisture content of rice at least once after the lid is closed until the boiling is detected in the temperature raising step.
The said control means adjusts at least one of the heating temperature in the said preheating process, and the electric power of the said temperature rising process according to the moisture content of the rice detected by the said moisture content detection means, The rice cooker characterized by the above-mentioned. A lid closing sensor for detecting that the lid is closed;
The rice cooker according to claim 1, wherein when the lid closing sensor detects that the lid is closed, the moisture content detecting means detects the moisture content of rice.

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