JP2010005273A - Rice cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rice cooker which has a keep-warm mode which controls drying, yellowish discoloration and progress of decay of rice and power consumption amount, and displays the state in the mode. <P>SOLUTION: The rice cooker includes a keep-warm-best-to-eat mode which controls at least drying or yellowish color change of rice in a keep-warm mode and keeps keep-warm-best-to-eat temperature for inhibiting decay for a predetermined time. When the operation means 11 selects the keep-warm-best-to-eat mode, a leaf mark 14, a pictorial display, is displayed on a display means 12 for informing that the keep-warm-best-to-eat mode is selected. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a rice cooker, and more particularly to a rice cooker with a heat retaining function characterized by a method for controlling the temperature of rice in a heat retaining process after rice cooking and a display method for a heat retaining mode.

  In conventional heat control of rice cookers, the heat retention temperature is the first temperature of the normal heat retention temperature and the second temperature lower than that, and the first heat retention temperature after the completion of rice cooking is controlled by the second temperature. However, what is characterized by controlling by the first temperature is disclosed (for example, see Patent Document 1).

Japanese Utility Model Publication No. 3-55397 (page 3, Fig. 2)

  According to Patent Document 1, in general, when the temperature of the cooked rice is raised to 70 ° C or higher, the water evaporates, and the color changes to yellow and the flavor drops extremely. On the other hand, if the temperature is kept lower than 70 ° C, the rotting occurs. It is said that there is a risk of germs breeding. Therefore, the heat retention control disclosed in Patent Document 1 is designed to lower the rice temperature until the temperature (second temperature, 55 ° C.) lower than the normal heat retention temperature (first temperature, 70 ° C.) is reached after rice cooking is completed. After the heater is turned off and the temperature reaches 55 ° C., the heater is re-energized and heated to 70 ° C., and thereafter, the constant temperature control at 70 ° C. is continued. As a result, the time during which the cooked rice is exposed to a high temperature of 70 ° C. or more after cooking is shortened, and the yellowing of the cooked rice during warming is small and the rice can be kept warm for a long time.

  However, the time during which the cooked rice is not exposed to a high temperature of 70 ° C. or higher after the cooking is completed is only a short time in which the temperature drops from 70 ° C. to 55 ° C. and is heated again to 70 ° C. Therefore, the effect of suppressing the yellowing change is very low for long-time heat retention, and the finish will be no different from the case of heat retention control that keeps the rice temperature constant at 55 ° C. without lowering the rice temperature to 55 ° C. after the completion of cooking. There was a problem.

  In addition, there is a problem that the amount of power consumption increases because the temperature is kept at a high temperature of 70 ° C. or higher for a long time.

  The present invention has been made to solve the above problems, and has a heat retention mode that suppresses drying, discoloration to yellow, progress of decay, and power consumption after the end of cooking, and in that mode. It aims at providing the rice cooker which displays a certain state.

  The rice cooker according to the present invention includes an inner pot for storing rice to be detachably stored in a main body case, a heating means for heating the inner pot, and a temperature detection for detecting the temperature of the cooked rice in the inner pot. Means, a means for selecting a heat retention mode, a display means for displaying a heat retention mode selected by the operation means, a timing means for measuring at least an elapsed time from the end of rice cooking, and the operation means after the end of rice cooking And a control means for controlling the heating means so as to hold the temperature of the rice detected by the temperature detection means for a predetermined time based on the time keeping signal selected by the time keeping means, and the temperature keeping mode is at least In addition to suppressing the drying or yellowing of the cooked rice in the inner pot, and including the temperature control mode for maintaining the temperature of the heat retention temperature for a predetermined period of time, the operation means includes If the eaten incubated mode is selected Ri, and displays a picture display for informing that the eaten incubated mode is selected on the display means.

  According to the present invention, since the cooked rice is maintained at the temperature of the hot plate for a predetermined time, the dryness or yellowing of the cooked rice can be suppressed and the spoilage can be suppressed, and delicious cooked cooked rice can be provided. In addition, power consumption can be suppressed by maintaining the temperature at a temperature that is lower than the normal temperature. Further, since the fact that the food warming mode has been selected is displayed in a picture display, it is easy to visually recognize that the food warming mode is in effect.

Hereinafter, a preferred embodiment of a rice cooker according to the present invention will be described with reference to the accompanying drawings. In addition, the same thing in the code | symbol of the component in each drawing shows the same component.

Embodiment 1 FIG.
Drawing 1 is a figure showing the structure of the rice cooker concerning Embodiment 1, (a) is a top view and (b) is a side view. Moreover, FIG. 2 is a block diagram of the drive circuit of this rice cooker. FIG. 3 is a diagram showing details of the operation means and display means of this rice cooker. FIG. 4 is a heat retention temperature sequence diagram showing a temperature transition during the heat retention of the rice cooker. FIG. 5 is a diagram showing changes in the dryness (moisture content) of cooked rice and changes in the b value indicating yellowness due to the difference in the temperature of the rice cooker. FIG. 6 is a diagram showing the killing rate of Bacillus subtilis due to the difference in the temperature of the rice cooker.

  In FIG. 1, a rice cooker 1 includes a main body 3 having an opening for taking in and out an inner pot 2 formed of a magnetic material such as SUS430, and is pivotally supported by the main body 3 so that the opening is formed. A lid 4 for opening and closing and a heating means 5 for heating an object to be cooked (not shown) placed in the inner pot 2 are provided. The heating means 5 is composed of a heating coil for electromagnetic induction heating, and is arranged in a spiral shape near the bottom surface of the inner pot 2. A high frequency current is supplied to the heating means 5 by the control means 6.

  The temperature detection means 9 comprised of a thermistor or the like is pressed against the bottom surface of the inner pot 2 from below by a compression spring or the like, detects the temperature of the bottom surface of the inner pot, and outputs a detection signal. Further, the operation means 11 is disposed substantially on the front surface of the main body 3 and is provided with various switches to be described later for outputting operation signals. The control means 6 receives a detection signal output from the inner pan temperature detection means 9, a time measurement signal output from the time measurement means 10 constituted by a timer, and an operation signal output from the operation means 11. A display signal is output to the display means 12 including a timer display unit and the like disposed at approximately the same position as the 10. The temperature detecting means 9 detects the temperature of the bottom surface of the inner pot in order to control the energization amount to the heating means at the time of cooking rice, and at the time of heat retention, the bottom surface of the inner pot previously stored in the control unit 8 as will be described later. The temperature of the cooked rice is estimated from the detected temperature of the bottom of the inner pot using the correlation table between the temperature of the cooked rice and the temperature of cooked rice. In addition, you may make it detect directly the temperature of the upper surface of the cooked rice in the inner pot 2 using the infrared sensor etc. which were provided in the lower surface of the cover body 4 so that the inner pot 2 might be opposed.

  The operation means 11 has a heat retention changeover switch 13 in addition to a “rice cooking” switch for starting rice cooking, an OFF of rice cooking operation or heat retention operation, or a “off / heat retention” switch for starting heat retention operation. . The heat retention mode is selected by the heat retention switch 13. That is, after the rice is kept warm for a predetermined time at the temperature of about 60 ° C., which is the temperature for keeping the rice, the temperature is kept at the normal temperature. “Tabagogo Insulation Mode” that switches to the insulation temperature of 73 ° C. is selected. The display means 12 has a display of a leaf mark 14 which is a picture display in addition to the display of “white rice, non-washed rice, normal, hard” such as a timer display section and a rice cooking menu. Further, as a display mode of the leaf mark 14, a lighting mode in which the leaf mark 14 is turned on, a blinking mode in which the leaf mark 14 is blinked, and an extinguishing mode in which the leaf mark 14 is turned off are provided.

  The control means 6 includes a power supply unit 7 and a control unit 8. The power supply unit 7 is configured by an inverter circuit or the like that supplies a high frequency current of several tens of kilohertz to the heating means 5. The control unit 8 is constituted by, for example, a microcomputer, a correlation table between the temperature of the bottom of the inner pot and the temperature of cooked rice, a rice cooking sequence that is a combination of the inner pot temperature and cooking time corresponding to each menu, and a heat retention mode. Is stored in advance, and the heating means 5 is controlled by controlling the power supply unit 7 in accordance with the rice cooking sequence and the temperature keeping temperature sequence based on the detection signal of the temperature detection means 9 and the timing signal of the timing means 10. Energize control.

Next, the operation will be described.
First, the rice to be cooked and water according to the amount of the rice are put in the inner pot 2. Thereafter, when the inner pot 2 is placed on the main body 3 and the lid body 4 is closed, the inner lid packing (not shown) is pressed against the flange portion of the inner pot 2 and hermetically sealed. Next, a rice cooking menu or the like (white rice, non-washed rice, normal, or hard) is selected by the “menu” switch and “rice” switch arranged on the operation means 11, and the heat retention mode (normal heat retention mode) is selected by the heat retention changeover switch 13. , Full-heat insulation mode) is selected. When the “cooking” switch is pressed, cooking is started.

  The rice cooking process is roughly divided into a preheating process, a cooking process, a steaming process, and a heat retaining process after the completion of cooking. Here, the operation | movement in the heat retention process after the completion of rice cooking is mainly demonstrated. Before pressing the rice cooker switch to start cooking rice, the heat retaining mode switch 13 selects the heat retaining mode. In the initial state when the power cord is inserted, the “heat-holding mode” is selected as the heat-retaining mode, and the leaf mark 14 is lit on the display means 12. Here, when the heat retention changeover switch 13 is pressed once, the mode is switched to the “normal heat retention mode”, and the leaf mark 14 is turned off. Every time this heat retention switch 13 is pressed, the “normal heat retention mode” and the “rice warm heat retention mode” are switched, and the selection of the heat retention mode can be confirmed by the presence or absence of the leaf mark 14 being displayed.

  When “normal warming mode” is selected, in the warming process, as shown by the solid line in the graph of FIG. 4, the cooked rice temperature decreases from the start of warming (rice temperature 90 ° C.) to approximately 73 ° C. (normal warming temperature). The energization of the heating means 5 is controlled so that the energization to the heating means 5 is turned off until approximately 73 ° C. is maintained. On the other hand, when the “rice warming mode” is selected, the temperature of the cooked rice is approximately 60 ° C. (rice warming temperature) from the start of heat keeping (rice temperature 90 ° C.) as shown by the one-dot chain line in the graph of FIG. The heating means 5 is turned off until the temperature is lowered (after 2 hours from the start of heat retention), and the heating means 5 is turned off so as to be kept at approximately 60 ° C. for 6 hours after reaching approximately 60 ° C. Thereafter (8 hours after the start of heat retention), the heating means 5 is energized so as to raise the cooked rice temperature to approximately 73 ° C. These are based on the detection signal output from the temperature detection means 9 and the time measurement signal output from the time measurement means 10, and the power supply unit 7 is controlled in accordance with the heat retention sequence stored in advance in the control unit 8, thereby increasing the power supply rate of the heating means 5. Control. Here, the food temperature is a temperature at which the drying or yellowing of the cooked rice is suppressed and the progress of decay is suppressed. In addition, as shown in the example of FIG. 3, the leaf mark 14 is lit and displayed during the period of “Tabagogo Warm Mode”, and the leaf mark 14 is displayed at the end of “Tabagogo Warm Mode” (8 hours after the start of heat insulation). Switch to blinking display. This blinking display is intended to notify that the “eat and heat retention mode” has ended.

  Here we will explain how to maintain the heat and taste of cooked rice, and how much energy is used. In general, a temperature of about 73 ° C. has been used as a heat retention temperature, but this temperature is intended for a long time of about 24 hours. In general, the higher the temperature, the faster the killing rate of Bacillus subtilis, etc., that is, the progress of spoilage is suppressed and the hygiene is higher. It was. However, according to recent surveys, among users who use heat insulation, heat insulation within 8 hours after the end of cooking rice accounts for more than 80%. This is due to changes in lifestyle, but the remaining rice is not kept warm, but it is well known that refrigerated or frozen and reheated in a microwave can eat delicious rice. . Furthermore, when comparing the power consumption required for one rice cooking process (from the preheating process to the steaming process) and the power consumption of the heat retention process, the power consumption of 6-8 hours is generally the power consumption of the rice cooking process. Is approximately the same. If kept warm for 24 hours, the rice cooking process can be performed 3 to 4 times within the amount of power used. In other words, the food is kept warm and eaten, and the energy is lost.

  FIG. 5 (a) shows the change in the degree of dryness (moisture content) of cooked rice with respect to the heat retention time at a heat retention temperature of 73 ° C. and 60 ° C., and FIG. 5 (b) shows the same yellow change. As shown in the figure, when the heat retention time is 8 hours later, when the heat retention temperature is 60 ° C., the dryness is suppressed by 7% and the yellow color change is suppressed by 40.7%, which is more delicious. You can see that FIG. 6 is a graph showing the killing rate of Bacillus subtilis using various temperatures as parameters. Here, in order to confirm the effect of suppressing the progress of decay, the state of Bacillus subtilis dying was observed. As shown in the figure, the higher the temperature, the faster the killing speed. For example, it takes 18 hours even at 55 ° C, but the bacteria are completely killed. Conversely, at 35 ° C, the bacteria are growing. Therefore, about 56 ° C. is appropriate as the lower limit of the temperature of the heat-retaining temperature in view of safety. In addition, 60 degreeC described in Embodiment 1 is a temperature generally said to be the temperature at which rice is transferred to "Ohitsu" and stored and is said to be most delicious and easy to eat. Therefore, it is desirable that the temperature of the heat retaining temperature is about 60 ° C. On the other hand, when the heat retention temperature is 73 ° C., the drying and yellowing of the cooked rice proceed, and therefore, the upper limit of the temperature of the rice heat retention temperature is about 70 ° C. For the measurement, spread the bacterial solution of Bacillus subtilis evenly on cooked rice (25 ° C), store it at each incubation temperature for an arbitrary period of time, put the cooked rice in physiological saline, and stir the supernatant on the agar medium. It applied and the method of counting the number of generated villages after 35 degreeC-24 hours was taken.

  In addition, there is a difference in the input power amount between the set values of the heat insulation temperatures. The power consumption when operating at 73 ° C. and 60 ° C. for 8 hours is 220 Wh and 172 Wh, respectively, and the heat retention at 60 ° C. is about 22% energy saving. By the way, when it is kept at 73 ° C. for 24 hours, it becomes 660 Wh, and it can be seen how the taste is reduced and wasteful power is consumed. In recent years, steam has been introduced during the 24-hour thermal insulation, and models that maintain dryness have also been put on the market. However, energy consumption is consumed because the amount of power consumed to generate steam regularly is added even though it is delicious. The amount increases. Also, returning to the normal heat retention level of 73 ° C 8 hours after the end of cooking rice is not sanitary, but from the viewpoint of energy saving, it is especially urged to end the heat retention within 8 hours. And the leaf mark 14 are associated with each other. However, the conventional “normal warming mode” can also be selected for users who need warming for a long time in their lifestyle.

As described above, it is possible to achieve a warming state that suits the user's preference by selecting the “normal warming mode” and the “tapago warming mode”, and the power consumption is reduced when the “tapago warming mode” is selected. As a result, a rice cooker that provides delicious rice with reduced hygiene by suppressing the progress of rotting of the cooked rice while suppressing the drying or yellowing of the cooked rice can be obtained. In addition, by turning on the picture display that clearly indicates the heat insulation mode, the usability is improved, and a rice cooker that can easily recognize the heat insulation mode is obtained.
Also, by making the picture display a leaf mark, the user is reminded of “ecology”, and a rice cooker that makes it easy to understand that the “tapago warming mode” is a warming mode that contributes to energy saving is obtained.
In addition, when switching to control that increases to the normal warming temperature after the “Tabagogo warming mode” is completed, the rice cooker that makes it easy to understand that the mode warming that contributes to energy saving has ended is achieved by switching the picture display from lighting to flashing. can get.
In addition, the predetermined time is switched by measuring the amount of power consumed in one rice cooking process (from the preheating process to the steaming process) and the time during which the power consumption in the heat retaining process is substantially equal, so the user must Energy saving can be realized in the time required.
In addition, by setting the food temperature to 56 ° C or more and 70 ° C or less, the lower limit temperature is set to the highest energy saving effect while suppressing the progress of decay, and the upper limit value obtains the minimum energy saving difference from the normal warming temperature. By adopting a temperature setting that can be used, both hygiene and energy saving can be achieved.

  In the embodiment, it has been explained that the end time of the “rice warming mode” is stored in advance as about 8 hours after the end of cooking rice. The switching time may be determined by measuring the amount of power in real time. Also, in the examples, it has been described that after switching to “Tabagogo Insulation Mode”, it is automatically switched to the normal insulation temperature. It is also possible to end the warming operation at the end of the “eat warming mode”. Furthermore, although the picture display during operation in the “tapagogo warming mode” is one leaf mark, a plurality of sheets may be used in combination, or a notification by sound generation means may be combined in addition to the leaf mark.

  From the above, by holding the temperature of the cooked rice using the rice cooker using the present invention, it is possible to clarify the range of the temperature holding time that is effective in suppressing power consumption while improving the heat insulation quality of the cooked rice. Therefore, the user can use it with peace of mind while paying attention to the reduction of power consumption. In addition, food can be safely stored for a long time while suppressing power consumption.

It is the upper side figure and side view which show the structure of the rice cooker which concerns on Embodiment 1 of this invention. It is a block diagram of the drive circuit of the rice cooker which concerns on Embodiment 1 of this invention. It is a front view of the operation means and display means of the rice cooker which concerns on Embodiment 1 of this invention. It is a heat retention temperature sequence diagram which shows the temperature transition at the time of heat retention of the rice cooker which concerns on Embodiment 1 of this invention. It is a figure which shows the dryness (water content) change of the rice rice by the difference in the heat retention temperature of the rice cooker which concerns on Embodiment 1 of this invention, and the change of b value which shows yellowness. It is a figure which shows the death rate of Bacillus subtilis by the difference in the heat retention temperature of the rice cooker which concerns on Embodiment 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rice cooker, 2 Inner pot, 3 Main body, 4 Lid body, 5 Heating means, 6 Control means, 7 Power supply part, 8 Control part 9 Temperature sensor, 10 Timing means, 11 Operation means, 12 Display means, 13 Insulation switch , 14 Leaf mark.

Claims (5)

An inner pot for storing rice to be detachably stored in the main body case;
Heating means for heating the inner pot;
Temperature detecting means for detecting the temperature of the cooked rice in the inner pot;
Operation means for selecting the heat retention mode;
Display means for displaying a heat retention mode selected by the operation means;
A timing means for timing at least the elapsed time from the end of cooking,
Control means for controlling the heating means so as to hold the temperature of the cooked rice detected by the temperature detection means for a predetermined time based on the heat retention mode selected by the operation means and the time measurement signal of the time measurement means after the completion of rice cooking. Prepared,
The heat-retaining mode includes at least a heat-retaining temperature mode that suppresses drying or yellowing of the cooked rice in the inner pan and continues the heat-retaining temperature for a predetermined period of time to suppress spoilage,
A rice cooker characterized in that, when the food warming mode is selected by the operating means, a picture display for notifying that the food warming mode is selected is displayed on the display means. 2. The rice cooker according to claim 1, wherein the pictorial display is at least one leaf mark. The rice cooker according to claim 1, wherein the temperature for keeping the temperature is 56 ° C. or more and 70 ° C. or less. The control means automatically switches to a normal heat-retaining mode in which heat is maintained at a temperature higher than the heat-retaining temperature after the end of the heat-retaining temperature mode, and changes the display method of the picture display. Item 1. A rice cooker according to item 1. 5. The rice cooking according to claim 4, wherein switching of the heat retention mode is performed by the time measuring means measuring and switching the time during which the amount of power consumed for one rice cooking and the amount of power consumed in the heat retention process are substantially equal. vessel.

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