JP2000018592A - Heating cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To assure an accurate weight judgement result at all times irrespective of a change in temperature conditions and of a secular change in a weight sensor. SOLUTION: The present heating cooker includes a weight sensor 16 for outputting a signal in response to a weight of foods, etc., and a control circuit 17. The control circuit 17 serves as weight decision means for judging the weight of any foods based upon a signal level outputted from the weight sensor 16 and a reference zero point set at present, and further serves as zero point alteration means. The function of the zero point alteration means is to read a signal from the weight sensor 17 every time before heating is started, and when the signal level is within a predetermined level range corresponding to a predetermined weight from the viewpoint of a reference zero point, alters and sets the reference zero point based upon the signal level.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooking device provided with a weight sensor.

[0002]

Conventionally, a heating cooker has been provided with a weight sensor for outputting a signal corresponding to the weight of food stored in a food placing plate in the cooking chamber. Examples of the weight sensor include a capacitance type and an inductance type. The capacitance-type weight sensor includes a movable electrode and a fixed electrode, and further includes an oscillation circuit and the like.The capacitance changes as the movable electrode bends due to the weight of the food and the separation distance from the fixed electrode changes. The change is extracted as a change in the output frequency of the oscillation circuit. That is, it is extracted as a frequency signal. This output frequency is given to a weight determining means including, for example, a microcomputer. In this weight determining means, the frequency when the food weight is zero (when nothing is placed on the food placing plate) is stored in advance as a zero point, and the output frequency from the weight sensor and the zero point are used to determine the food weight. Is determined.

The inductance type weight sensor is
Providing a core member so as to be displaced according to the food weight and providing a winding at a stationary portion, and including an oscillation circuit, the displacement distance of the core member with respect to the winding changes according to the food weight, whereby This is based on the fact that the inductance of the winding changes. Also in this case, the change in inductance is obtained by a change in the output frequency of the oscillation circuit.
The weight determination result is used as control data of the cooking time and the heating intensity.

[0004] However, conventionally, in a cooking device, the environmental temperature in winter and summer is different, and the temperature of the cooking device itself is affected by the heating cooking (the initial temperature differs between the first cooking and the continuous cooking). ), The weight sensor is also affected by the temperature, the output signal level may change even with food of the same weight, and the signal level may increase over time, Conversely, it becomes smaller. However, in the above configuration, since the zero point is fixedly set on the heating cooker side, the accuracy of weight determination deteriorates with temperature conditions and aging, and a problem occurs in that the cooking finish varies. there were.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to always obtain a weight determination result with higher accuracy irrespective of changes in temperature conditions and aging of a weight sensor. An object of the present invention is to provide a heating cooker that can perform heating cooking satisfactorily.

[0006]

According to a first aspect of the present invention, there is provided a weight sensor for outputting a signal corresponding to the weight of a food or the like accommodated in a cooking chamber, a level of the signal output from the weight sensor, Weight determination means for determining the weight of the food from the reference zero point set at the present time, and each time before the start of heating, read the signal from the weight sensor, and the signal level becomes a predetermined weight from the reference zero point And a zero point changing means for changing and setting the reference zero point based on the signal level when the value is within the range of the corresponding predetermined level. In the above-described configuration, the weight determination unit determines the level of the signal output from the weight sensor,
The weight of the food is determined based on the currently set reference zero point. In this case, the zero point changing means
Before the start of heating, that is, before the food is stored in the cooking chamber, the reference zero point is changed and set every time. Therefore, this reference zero point becomes the latest reference zero point before heating and cooking. Thus, when the cooking device is used in winter or summer, a reference zero point corresponding to the environmental temperature is set, and even in the case of the first cooking or in the case of continuous cooking, the reference in the temperature state is set. Even if the output signal level changes due to the aging of the weight sensor, a reference zero point corresponding to the level is set. As a result, when performing weight determination based on the output signal from the weight sensor, the output signal level can be determined based on the appropriate reference zero point, and the weight determination accuracy is always appropriate.

In particular, when the zero point is changed and set, when the level of the signal from the weight sensor is within a range of a predetermined level corresponding to a predetermined weight when viewed from a reference zero point set at the present time, the signal level is set. The reference zero point is changed and set based on the reference zero point, so that the reference zero point changed and set this time is not set to a value extremely deviated from the reference zero point before the change, that is, the temperature condition change. The change of the reference zero point is set within an appropriate range in consideration of the aging and aging, and the reference zero point with high reliability is set.

According to a second aspect of the present invention, the zero point changing means reads a signal from the weight sensor every time before starting heating,
When a situation where the signal level is within a range of a predetermined level corresponding to a predetermined weight when viewed from the reference zero point continues for a predetermined time, the reference zero point is changed and set based on the signal level. Has features. In this configuration, when the level of the signal from the weight sensor is within a predetermined level range corresponding to the weight of the predetermined range from the reference zero point for a predetermined time, the reference zero point is changed and set. Point setting accuracy is increased. In other words, if the weight sensor vibrates when the signal from the weight sensor is picked up (the weight sensor is likely to vibrate structurally), there is a concern that the effect may cause a temporary error in the signal level, In the above configuration, the reference zero point is changed and set after the signal from the weight sensor is stably obtained, thereby increasing the setting accuracy of the reference zero point.

According to a third aspect of the present invention, the zero point changing means reads the signal from the weight sensor every time before the start of heating, and the signal level falls within a predetermined level range corresponding to a predetermined weight when viewed from the reference zero point. A certain situation continues for a predetermined time, and
When the difference between the maximum value and the minimum value of the signal level is equal to or less than a predetermined value, the reference zero point is changed and set based on the signal level.

[0010] Even if the signal from the weight sensor is kept within a predetermined level range for a predetermined time, it is more advantageous to set the reference zero point if the fluctuation in the signal level is small. In this regard, in the above configuration, the situation where the signal level is within the range of the predetermined level corresponding to the predetermined weight as viewed from the reference zero point continues for the predetermined time, and the difference between the maximum value and the minimum value of the signal level is the predetermined value. In the following cases, the reference zero point is changed and set based on the signal level, so that a more appropriate reference zero point can be set.

In the second or third aspect of the present invention, the zero point changing means may set the zero point of the food weight based on a value obtained by averaging the levels of the signals read a plurality of times (claim 4). Invention). This makes it possible to set a more appropriate reference zero point.

According to a fifth aspect of the present invention, the zero point changing means has a fixed zero point set as an invariable value separately from the reference zero point, and reads a signal from the weight sensor every time before starting heating. The signal level is within a range of a predetermined level corresponding to a predetermined weight when viewed from the reference zero point, and
The present invention is characterized in that the reference zero point is changed and set based on the signal level when the signal level is equal to or less than an allowable value for a predetermined weight as viewed from the fixed zero point.

When the reference zero point is updated when the read signal level is within a predetermined range with respect to the reference zero point,
As the number of updates increases, the absolute value of the reference zero point may greatly deviate from the initial reference zero point. In this case, the reference zero point is inappropriate. However, in the above configuration, there is a fixed zero point set as an invariable value separately from the reference zero point, and the level of the signal from the weight sensor is within a range of a predetermined level corresponding to a predetermined weight when viewed from the reference zero point. And, when the level of the signal is equal to or less than a predetermined weight allowable value as viewed from the fixed zero point, the reference zero point is changed and set based on the signal level. The change of the reference zero point is not executed, that is, the problem of setting an inappropriate reference zero point is eliminated.

According to a sixth aspect of the present invention, there is provided the first aspect,
The invention according to 2, 3, or 5, further comprising a door that opens and closes the cooking chamber, and a door opening and closing detecting unit that detects opening and closing of the door.
It is characterized in that the zero-point changing means performs a zero-point change setting operation when the opening of the door is detected by the door opening / closing detecting means before cooking.
When the cooking is completed, the door is opened to take out the food in the cooking chamber and then closed. Further, the door is opened immediately before the start of heating and cooking, and is closed after the food is stored. As can be understood from now on, the change from the opening of the door to the closing of the door often occurs when the food is taken out or stored. The situation in which the door remains open is often a situation in which there is no food. Then
By performing the zero point change setting operation when the door is opened, the zero point change setting operation in a state where the food is stored can be minimized, and the erroneous setting is eliminated.

In this case, after performing the zero point change setting operation when the door opening is detected by the door opening / closing detecting unit before cooking, the zero point changing unit performs the zero point changing even if the door opening is detected thereafter. A configuration in which the point change setting operation is not performed may be adopted (the invention of claim 7). By doing so, erroneous setting of the reference zero point is eliminated.

That is, when the reference zero point is changed and set under the condition that the level of the signal from the weight sensor is within the range of a predetermined level corresponding to a predetermined weight when viewed from the reference zero point when the door is opened. Then, when the door is opened,
Even when food below the specified range weight is stored,
There is a concern that this food weight may be set to the reference zero point. However, in the above configuration, after the zero point change setting operation is performed, the zero point change setting operation is not performed even if the door opening is detected thereafter. Is stored, the erroneous setting of the reference zero point is eliminated.

According to an eighth aspect of the present invention, in the first, second, third or fifth aspect of the present invention, a door for opening and closing the cooking chamber, a door opening and closing detecting means for detecting the opening and closing of the door, and a predetermined condition after the cooking is completed. Automatic power-off means for turning off the power when is satisfied, wherein the zero point changing means is in a state where the power is turned off by the automatic power-off means and the opening of the door is detected by the door open / close detecting means. A feature is that the zero point change setting is sometimes performed.

The state in which the power is turned off by the auto power-off means is before the start of the next cooking (even after the end of the previous cooking). Often it is. In addition, the fact that the automatic power-off state has occurred means that a considerable amount of time has passed since the completion of cooking, and food is hardly contained in the cooking chamber. Therefore, performing the zero-point change setting when the power is turned off by the automatic power-off means and the door is open as in the above configuration is optimal as the zero-point change timing.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, in FIGS. 2 and 3, the heating cooker main body 1 includes an outer box 2 and an inner box 3, and the inside of the inner box 3 is a cooking chamber 4. A drive shaft 5a is inserted through a bottom plate in the cooking chamber 4, and a lower end of the drive shaft 5a is supported by a weight sensor 16, which will be described later, and the drive shaft 5a is rotated by the turntable motor 5. It has become. A rotating body 6 formed of a metal disk formed in a net shape is connected to the upper end of the drive shaft 5a. A mounting plate 7 on which food is placed is detachably disposed on the rotating body 6. The cooking chamber 4 is opened and closed by a door 8. Further, an upper heater 9 composed of a tubular heater is disposed on the upper surface of the cooking chamber 4, and a lower heater 10 composed of a planar heater is disposed outside the bottom plate.

A panel 11 is provided on the front side of the heating cooker main body 1 on the side of the door 8, and is provided with various switch groups 12, a display 13 and the like. In addition,
The switch group 9 includes a selection switch for selecting between magnetron heating cooking and heater heating cooking, a start switch, a time setting switch for setting a heating cooking time, and a cancel switch. A machine room (not shown) is formed on the back side of the panel 11, in which a magnetron 14 and a cooling fan 15 shown in FIG. 1 are disposed.

A weight sensor 16 is provided below the bottom plate of the cooking chamber 4, supports the drive shaft 5a, and outputs a signal corresponding to the load applied to the drive shaft 5a. ing. That is, the weight sensor 16
Is a capacitance type, not shown, but includes a movable electrode and a fixed electrode, and further includes an oscillation circuit, and the like. Change, and the change is taken out as a change in the output frequency of the oscillation circuit. That is, it is extracted as a frequency signal. This output frequency is given to the control circuit 17 shown in FIG.

The control circuit 17 includes, for example, a microcomputer. The control circuit 17 receives each switch input from a switch input section 18 provided with the switch group 12, and has a door formed of, for example, a limit switch. A signal is provided from the open / close sensor 19. The door opening / closing sensor 19 corresponds to a door opening / closing detecting means, and outputs a door opening detection signal So when the door 8 is opened, and outputs a door closing detection signal Sc when the door 8 is closed. Has become. The control circuit 17 drives and controls the display 13 according to the heating and cooking control program, and also opens the drive circuit 20 to drive the turntable motor 5, the upper heater 9, the lower heater 10, the magnetron 14, and the cooling fan 15. In addition to being controlled, writing and reading to and from the nonvolatile memory 21 are performed.

The weight sensor 16 is, for example, as shown in FIG.
In FIG. 5, "0 g" indicates a state in which the placing plate 7 is disposed on the rotating body 6 and no food is placed.
Is the so-called zero point. In FIG. 5, the temperature in the cooking chamber 4 is 25
° C, and when the temperature increases, the characteristic line Pa tends to shift to a lower frequency direction (see a two-dot chain line). That is, the zero point becomes lower.

The control circuit 17 functions as weight determining means and zero point changing means, and the weight determining method is as follows. That is, the control circuit 17 stores the relationship between the frequency data and the food weight data shown in the relationship of FIG. 5, and the zero point (in this case, the output frequency of 50.00 kHz) and the output frequency from the weight sensor 16 are stored. The weight is determined based on.

The control circuit 17 previously stores data used for weight determination in the ROM. The data will be described below (see FIG. 7). Fixed zero point WF: Stored in advance by the manufacturer before product shipment. Allowable value γ: Frequency of a predetermined weight with respect to fixed zero point WF, and the predetermined weight is, for example, “250 g”. Predetermined level α: reference zero point W0 or Wa (described later)
At a frequency level corresponding to a predetermined weight, for example, “60 g”.

On the other hand, the non-volatile memory 21 stores a reference zero point W0, which is set and stored by a user operation. That is, in the instruction manual attached to the cooking device, a setting operation method of the reference zero point W0 is described, and if the operation is performed according to the setting operation method, the reference zero point W0 is stored. I have. As a setting operation method, for example, a power plug is connected to a commercial power source, the placing plate 7 is placed (no food is placed), the door 8 is closed, and the cancel switch is turned on. When this operation is performed, the control circuit 17 writes the frequency level output from the weight sensor 16 at that time into the nonvolatile memory W0 as the reference zero point W0. This reference zero point W0 is initially used as an initial value of the change setting of the reference zero point. When the change setting of the reference zero point is performed, the reference zero point is hereinafter referred to as the reference zero point Wa. used.

The reference zero point Wa is automatically executed by the setting control of the control circuit 17 each time before the start of cooking. For the setting control of the reference zero point Wa, see also the flowchart of FIG. I will explain. This flowchart starts when the power plug is connected to the commercial power supply. In this flowchart, the setting control of the reference zero point W0 based on the operation of the user described above is omitted.

Now, the first reference zero point change setting operation will be described. In this case, the reference zero point W0 for the initial value by the user operation is set, the placing plate 7 is arranged, the cooking is completed, and no food is placed. The flow of the flowchart will be described as (not accommodated).

In step S1, the fixed zero point W
F, the allowable value γ, and the predetermined level α are read. In step S2, the reference zero point W0 for the initial value by the user operation
Is determined whether or not (non-volatile memory 2
It is determined whether the reference zero point W0 is stored in 1). In this case, since it is assumed that the reference zero point W0 has been set, the process shifts to step S3 to determine whether or not it is before cooking. That is, it is determined whether or not the cooking operation is being executed by the heating cooking control program. In this case, since it is assumed that the cooking operation has not been performed, it is determined that cooking has not been performed, and the process proceeds to step S4.

In step S4, it is determined whether or not the door 8 has been opened from the closed state, that is, whether or not the door opening / closing sensor 19 has received the door open detection signal So. If so, the process moves to step S5.

In this step S5, FIG.
As shown in the figure, the frequency data storage unit E1 in the RAM
ＥE5 (see FIG. 6) are cleared, and the parameter Q for starting / ending the zero point setting operation is set to “1” (“1” means start, “0” means end or stop). means). In the next step S6, it is determined whether or not the zero point setting operation is being performed, that is, whether or not the parameter Q is "1". If the zero point setting operation is being performed, the process proceeds to step S7 and the output from the weight sensor 16 is output. The frequency is read and stored as frequency data Wa1 in the first-stage storage unit E1 of the frequency data storage units E1 to E5 (see FIG. 6B). In this case, each storage unit E
The stored contents of 1 to E4 are moved to a higher order. This frequency is obtained by integrating frequency pulses for 0.25 seconds each time and measuring the frequency from the integrated value.

Then, in the next step S8, each of the above E
The difference between the maximum value and the minimum value of the stored data 1 to E5 (see FIG. 6)
In the case of (b), the difference between "Wa1" and "0" (this difference is treated as an absolute value) is converted into a weight. Then, in a step S9, it is determined whether or not the converted weight is “20 g” or less. This “20 g” is a weight-converted value of a predetermined value corresponding to the difference between the maximum value and the minimum value. Here, the weight conversion value of the difference between the frequency data “Wa1” and “0” is normally “20 g” or more, and the process returns to step S2 according to “NO” in step S9. This step S
In 2, since the reference zero point W0 has already been set,
The process again proceeds to steps S3 and S4. If the door 8 remains open, there is no change from the door opening to the door closing, so the process proceeds to step S15 according to "NO".

In step S15, it is determined whether or not there has been a change from the opening of the door to the closing of the door.
The process proceeds to step S6 described above, where step S6 (determination of whether or not the reference zero point is being set), step S7 (reading and storage of frequency data), step S8 (the difference between the maximum value and the minimum value is converted into weight) and Step S9 (determination as to whether the weight is 20 g or less) is executed, and in a normal case, the process shifts from step S9 to step S2 again, and the above-described flow is repeated.

That is, if the door 8 is left open,
Frequency data from the weight sensor 16 is sequentially read, and frequency data (Wal to Wa1) for five times is read.
If Wa5) is stored in the frequency data storage units E1 to E5 as shown in FIG. 6D, the frequency data "0" disappears, and if there is no abnormality in each value of the frequency data Wa1 to Wa5, The weight conversion value of the difference between the maximum value and the minimum value in step S8 is equal to or less than the weight conversion value “20 g”. If at least one abnormal value is shown in the frequency data Wa1 to Wa5, the value exceeds "20 g". Therefore, in order to shift to "YES" in step S9, the frequency data Wa1 for five consecutive times is required. Wa5 needs to be an approximate value (a continuously stable value). In this case, in this flowchart, it takes approximately 0.25 seconds to read each signal.
When stable frequency data is obtained for 25 seconds, the process proceeds from "YES" in step S9 to step S10.

In step S10, of the five consecutive frequency data Wa1 to Wa5, the three frequency data except the maximum value and the minimum value are averaged, and the average frequency data is set at this time. The weight is converted based on the reference zero point (in this case, the reference zero point W0). Then, in a step S11, it is determined whether or not the converted weight (converted weight viewed from the reference zero point W0) is within a predetermined weight “60 g” (this corresponds to a predetermined level “α”).

Here, five consecutive frequency data Wa1
Wa5 is a stable value whose mutual difference is within “20 g”. Of these, three intermediate frequency data are converted weights of “60 g” from the reference zero point W0, which means that the frequency data for five consecutive times Wa1 to Wa5 indicate that all the data show values close to “60 g ± 10 g”.

In step S11, "6"
0g ", the average frequency data is converted into a weight as viewed from the fixed zero point WF, and in step S13, the converted weight corresponds to a preset allowable value γ. It is determined whether or not the weight is within the aforementioned “250 g”. If the weight is within the “250 g”, the average frequency data is set as a new reference zero point Wa, for example, R
Store in the AM (change and set).

If it is determined in step S15 that there has been a change from the door opening to the door closing, the process proceeds to step S16 to determine whether or not the zero point setting operation is being performed.
If the zero point setting operation is being performed, the above-described parameter Q is set to “0” in step S17, and the process proceeds to step S6.
In other words, the zero point setting operation started on the condition that the door 8 is opened is stopped when the door 8 is closed halfway (within less than five times of reading the appropriate frequency data). Is done. Therefore, the previous reference zero point is used for the weight determination as the reference zero point.

The relationship between the above flowchart and the situation of the user will be described with reference to FIG. 7. It is assumed that the placing plate 7 is not set at this time. When the door 8 is opened before cooking (time t1), the frequency data storage units E1 to E5 of the control circuit 17 are cleared (frequency “0”). Then, the control circuit 17 reads and stores the frequency from the weight sensor 16 for 0.25 seconds each time. This reading and storing operation is continued until the frequencies of the storage units E1 to E5 do not have a difference of “20 g” from each other. Thus, at time 1, although the placing plate 7 is not set, the weight sensor 16 outputs a frequency Wx considerably higher than “0”, and there is a difference of “20 g”.

After the placing plate 7 is set (time t2), the frequency corresponding to food zero is read and stored. The stored values (Wa1 to Wa5) for five times are the maximum value and the maximum value. The minimum value is “20 g” or less, and the converted weight from the reference zero point W0 is “60 g” (absolute value).
If the following, the reference zero point Wa is set (time t
3). At the same time, the zero point change setting operation ends.

When the placing plate 7 is set (t2)
In this case, the frequency becomes abnormally high or low due to the occurrence of the vibration. However, although the frequency of this portion is temporarily stored, the condition such as “20 g” or less is not cleared. The frequency of the batch is stored.

Thereafter, the food is stored (time t4), the door 7 is closed (time t5), cooking starts at time 6 (when the start switch is operated), and the weight determination operation is performed. Become. In this case, the frequency is read from the weight sensor 16 for 0.25 seconds and measured, and this frequency data is converted into a weight viewed from the reference zero point Wa at this time.

When the cooking is completed, the above-described reference zero point setting operation is executed every time before the cooking is started. In such a reference zero point change setting operation of the second shift, the previously set reference zero point Wa is set.
(The reference zero point W0 is used only at the beginning).

According to this embodiment, the following effects can be obtained. That is, before the start of heating, the change setting control for the reference zero point W0 or Wa is performed every time, so that the newly set reference zero point Wa becomes the reference zero point Wa according to the situation before the heating and cooking. Thus, when the cooking device is used in winter or summer, the reference zero point Wa corresponding to the environmental temperature is set,
Also, in the case of the first cooking or the continuous cooking, the reference zero point Wa in the temperature state is set, and even if the output frequency level changes due to the aging of the weight sensor 16, it is determined according to the level. The reference zero point Wa is set. Thus, when the food weight is determined by the control circuit 17, the output frequency level can be determined based on the appropriate reference zero point Wa, and the weight determination accuracy is always appropriate.

In particular, when changing the reference zero point W0 or Wa, the level of the frequency from the weight sensor 16 is set to the reference zero point W0 or W that is currently set.
a, the reference zero point W based on the frequency level is within a predetermined level range corresponding to a predetermined weight, in this case, substantially within a reduced weight range of “60 g ± 10 g”.
0 or Wa is changed and set, the reference zero point Wa changed and set this time is changed to the reference zero point W0 before the change.
Alternatively, the reference zero point W0 or Wa is changed and set within an appropriate range in consideration of a change in temperature conditions and a change over time without being set to a value extremely deviated from Wa. A high reference zero is set.

Further, in this embodiment, the frequency from the weight sensor 16 is read, and the frequency level is within the range of approximately "60 g ± 10 g" when converted from the reference zero point W0 or Wa at this time. When the situation continues for a predetermined time of 1.25 seconds, the reference zero point W0 or Wa is changed and set based on the frequency level, so that the frequency from the weight sensor 16 can be obtained stably. The zero point Wa is changed and set, so that the setting accuracy of the reference zero point Wa is increased.

The weight sensor 16 is structurally liable to vibrate. If the heating cooker body 1 vibrates when the door 8 is opened, the weight sensor 16 also vibrates, and the vibration is attenuated. It may take some time. In such a case, if the frequency level is equal to the reference zero point W0
Alternatively, even if it is within a predetermined range from Wa, the frequency level change from the weight sensor 16 may become severe, and the setting accuracy of the reference zero point Wa may be reduced.

In this embodiment, the reference zero point W0 or Wa is changed when the difference between the maximum value and the minimum value of the frequency from the weight sensor 16 is equal to or smaller than a predetermined value (20 g in weight). Accordingly, the reference zero point W0 or Wa is changed and set in a state where there is no error factor such as vibration, so that the setting accuracy of the reference zero point Wa increases.

In particular, since the reference zero point Wa of the food weight is set based on the average value of the frequency levels read five times in this case, the reference zero point can be set more appropriately. .

When the reference zero point Wa is updated while the frequency level read with respect to the reference zero point W0 or Wa is within a predetermined range, the absolute value of the reference zero point Wa increases as the number of updates increases. May greatly deviate from the initial reference zero point W0. In this case, the reference zero point is inappropriate. However, the above configuration has a fixed zero point WF set as an invariable value separately from the reference zero point W0 or Wa,
The frequency level from the weight sensor 16 is fixed to the zero point WF
In view of this, the reference zero point W0 or Wa is changed and set based on the frequency level when it is equal to or less than the allowable value γ corresponding to the weight “250 g”. Alternatively, the Wa change setting is not performed, that is, the setting of the inappropriate reference zero point can be eliminated.

Further, according to the present embodiment, the zero point change setting operation can be performed while satisfactorily grasping the time when food is not stored. That is, when the cooking is completed, the door 8 is opened to take out the food in the cooking chamber 4 and then closed. The door 8 is also opened immediately before the start of heating and cooking, and closed after the food is stored. As can be understood from this, the change from the opening of the door 8 to the closing of the door 8 is often at the time of taking out the food or storing the food. The situation in which the door 8 remains open is often a situation where there is no food. Thus, by performing the zero point change setting operation when the door 8 is opened, the zero point change setting operation in a state where the food is stored can be minimized, and the erroneous setting is eliminated.

Furthermore, since the initial reference zero point W0 is set by the user, an appropriate value can be obtained as the initial reference zero point. In other words, it is conceivable to use a fixed zero point WF as the initial reference zero point. This fixed zero point FW is set before shipment of the heating cooker as a product, and is set at the time of shipment or transportation during the course. There is also a concern that the output of the weight sensor may shift at times. Therefore, it can be said that it is somewhat unsuitable as an initial reference zero point. If there is no such concern, the fixed zero point WF may be used as the first reference zero point.

The present invention may be modified as in the following (A) to (C). (A) Before cooking, after the opening of the door 8 is detected by the door opening / closing sensor 19 and the zero point change setting operation is performed, the zero point change setting operation is performed even after the opening of the door 8 is detected. It may not be done. By doing so, erroneous setting of the reference zero point is eliminated. That is, when the door 8 is opened, the reference zero point is changed and set under the condition that the frequency level from the weight sensor 16 is within the range of the reference zero point W0 or a predetermined level corresponding to a predetermined weight when viewed from Wa. Then, when the door 8 is opened,
Even when a food item having a predetermined weight or less (for example, a light food item having a weight of “60 g ± 10 g” or less) is stored, there is a concern that the weight of the food item may be set to the reference zero point.

However, as described above, after the zero point change setting operation is performed, if the zero point change setting operation is not performed even if the door 8 is subsequently opened, the door 8 is set after the reference zero point is set. Is released and the reference zero point is not set erroneously even if the light weight food is stored.

(B) automatic power-off means for turning off the power when predetermined conditions are satisfied after cooking is completed, wherein the power is turned off by the automatic power-off means and the door is detected by the door open / close detecting means. May be configured to perform the zero point change setting when the release is detected.

The situation in which the power is turned off by the auto power-off means is before the start of the next cooking (even after the end of the previous cooking). Often it is. In addition, the fact that the automatic power-off state has occurred means that a considerable amount of time has passed since the completion of cooking, and food is hardly contained in the cooking chamber. Therefore, performing the zero-point change setting when the power is turned off by the automatic power-off means and the door is open as in the above configuration is optimal as the zero-point change timing.

(C) In the above embodiment, the frequency data from the weight sensor 16 is read five times. However, the frequency data may be read once, and the intended purpose can be achieved by doing so. In addition, the present invention can be implemented with various modifications other than the above.For example, the weight sensor may be an inductance type, and the door opening / closing detecting means includes:
An optical sensor or the like may be used. The output signal from the weight sensor can be a voltage signal if a frequency / voltage converter is used.

[0058]

As apparent from the above description, the present invention has the following effects. According to the first aspect of the present invention, the reference zero point is changed and set every time before the start of heating by the zero point changing means, so that the reference zero point is appropriately adjusted according to the temperature condition and the aging state of the weight sensor. As a result, when weight determination is performed based on the output signal from the weight sensor, the output signal level can be determined based on an appropriate reference zero point, and the weight determination accuracy is always appropriate. In addition, when the reference zero point is changed and set, when the level of the signal from the weight sensor is within a range of a predetermined level corresponding to a predetermined weight when viewed from the currently set reference zero point, the signal level is used. Since the reference zero point is changed and set, the reference zero point changed and set this time is not set to a value extremely shifted from the reference zero point before the change, and a highly reliable reference zero point is set. Can be set.

According to a second aspect of the present invention, when a situation where the signal level from the weight sensor is within a range of a predetermined level corresponding to a predetermined weight from a reference zero point continues for a predetermined time,
Since the reference zero point is changed and set based on the signal level, the reference zero point is changed and set after the signal from the weight sensor is stably obtained, thereby setting accuracy of the reference zero point. Will be higher.

According to the third aspect of the present invention, the situation where the signal level from the weight sensor is within the range of the predetermined level corresponding to the predetermined weight from the reference zero point continues for the predetermined time, and the maximum value of the signal level and When the difference from the minimum value is equal to or less than a predetermined value, the reference zero point is changed and set based on the signal level, so that the reference zero point can be changed and set without an error factor such as vibration, Thus, the setting accuracy of the reference zero point can be improved.

According to the fourth aspect of the invention, the reference zero point of the food weight is set based on the average value of the levels of the signals read a plurality of times, so that a more appropriate reference zero point can be set. According to the invention of claim 5, having a fixed zero point set as an invariable value separately from the reference zero point, a signal from the weight sensor is read every time before the start of heating, and the signal level is set to the reference zero point. When the signal level is within a range of a predetermined level corresponding to a predetermined weight, and the signal level is equal to or less than an allowable value of a predetermined weight when viewed from the fixed zero point, the reference zero point is set based on the signal level. Since the configuration is changed and set, there is no problem that an appropriate reference zero point is set.

According to the sixth aspect of the invention, the zero point change setting operation is performed when the door is opened by the door open / close detecting means before cooking, so that the food is stored. The zero point change setting operation of
Erroneous settings are eliminated. According to the invention of claim 7, after the zero point change setting operation is performed while the door opening is detected by the door opening / closing detection unit before cooking, the zero point change setting operation is performed even if the door opening is detected thereafter. With the configuration in which the operation is not performed, the erroneous setting of the reference zero point is eliminated.

According to the eighth aspect of the present invention, the zero point change setting is performed when the power is turned off by the automatic power off means and the door opening is detected by the door open / close detecting means. Therefore, it is the best timing for changing the zero point.

[Brief description of the drawings]

FIG. 1 is a block diagram of an electrical configuration showing an embodiment of the present invention.

FIG. 2 is a perspective view of a cooking device.

FIG. 3 is a vertical side view of the cooking device.

FIG. 4 is a flowchart of a zero point change setting operation;

FIG. 5 is a diagram showing a relationship between output frequency and food weight.

FIG. 6 is a diagram showing a state of storing frequency data.

FIG. 7 is a diagram showing an example of a change in frequency data.

[Explanation of symbols]

Reference numeral 4 denotes a cooking chamber, 7 denotes a placing plate, 8 denotes a door, 16 denotes a weight sensor, 17 denotes a control circuit (weight determining means, zero point changing means), and 19 denotes a door open / close sensor (door open / close detecting means).

Claims (8)

[Claims] 1. A weight sensor for outputting a signal corresponding to the weight of food or the like accommodated in a cooking chamber, a level of a signal output from the weight sensor, and a reference zero point set at the present time. Weight determination means for determining the weight of the food; each time before the start of heating, a signal from the weight sensor is read, and when the signal level is within a range of a predetermined level corresponding to a predetermined weight when viewed from the reference zero point. And a zero point changing means for changing and setting the reference zero point based on the signal level. 2. A weight sensor for outputting a signal corresponding to the weight of a food or the like contained in a cooking chamber, and a food based on the level of the signal output from the weight sensor and a currently set reference zero point. A weight determination means for determining the weight of the weight sensor; and reading a signal from the weight sensor each time before the start of heating, and determining that the signal level is within a range of a predetermined level corresponding to a predetermined weight when viewed from the reference zero point. A heating cooker comprising: zero-point changing means for changing and setting the reference zero point based on the signal level when the time continues. 3. A weight sensor for outputting a signal corresponding to the weight of a food or the like contained in a cooking chamber, and a food based on the level of the signal output from the weight sensor and a currently set reference zero point. A weight determination means for determining the weight of the weight sensor; and reading a signal from the weight sensor each time before the start of heating, and determining that the signal level is within a range of a predetermined level corresponding to a predetermined weight when viewed from the reference zero point. Zero point changing means for changing and setting the reference zero point based on the signal level when the difference between the maximum value and the minimum value of the signal level is equal to or less than a predetermined value. Characterized heating cooker. 4. The zero point changing means according to claim 2, wherein the zero point changing means sets the zero point of the food weight based on an average value of the levels of the signals read a plurality of times.
The heating cooker as described. 5. A weight sensor for outputting a signal corresponding to the weight of a food or the like contained in a cooking chamber, and a food based on the level of the signal output from the weight sensor and a currently set reference zero point. Weight determination means for determining the weight of, having a fixed zero point set as an invariable value separately from the reference zero point, every time before the start of heating, read the signal from the weight sensor, the signal level is the When the signal level is within a range of a predetermined level corresponding to a predetermined weight when viewed from the reference zero point, and the signal level is equal to or less than an allowable value for a predetermined weight when viewed from the fixed zero point, the reference is performed based on the signal level. A heating cooker comprising: a zero point changing means for changing and setting a zero point. 6. A door for opening and closing the cooking chamber, and a door open / close detecting means for detecting the opening / closing of the door, wherein the zero point changing means detects the opening of the door by the door open / close detecting means before cooking. The heating cooker according to claim 1, wherein a zero point change setting operation is performed when the operation is performed. 7. The zero point changing means executes the zero point change setting operation before the cooking when the door opening / closing detecting means detects the opening of the door, and thereafter performs the zero point changing even if the door opening is detected thereafter. 7. The cooking device according to claim 6, wherein the change setting operation is not performed. 8. A door for opening and closing the cooking chamber, a door open / close detecting means for detecting the opening / closing of the door, and an automatic power-off means for turning off the power when predetermined conditions are satisfied after completion of the cooking. The point changing means performs the zero point change setting when the power is turned off by the auto power off means and the door opening is detected by the door opening / closing detecting means. Claim 1, 2, 3, or 5
A heating cooker according to claim 1.