Abstract: A method for targeted heating element control can include: sampling measurements, determining one or more occupied regions based on the measurements, determining one or more food types, controlling appliance operation based on the occupied regions and food types, optionally providing real-time feedback to the user for food placement within the cavity, optionally sampling training measurements, optionally determining a cavity occupancy region classifier, and/or any other suitable elements.

Abstract: An electromagnetic cooking device and method of controlling the same is provided herein. The cooking device has a cavity in which a liquid is placed and a plurality of RF feeds configured to introduce electromagnetic radiation into the cavity for heating the liquid. A controller is provided and is configured to: analyze forward and backward power at the plurality of RF feeds to calculate efficiency; determine and monitor a coefficient of variation of the efficiency; detect a boiling state in the liquid based on changes in the coefficient of variation; and adjust a power level of the electromagnetic radiation in response to detection of the boiling state to prevent the liquid from splattering.

Abstract: A cooker includes a heating chamber configured to accommodate an object to be heated, a heater configured to heat the object to be heated accommodated in the heating chamber, heating controller (14) configured to control the heater for heating, an image capturing unit configured to capture an image inside the heating chamber, and mark detector (28) configured to detect a specific mark from the image captured by the image capturing unit. Heating controller (14) disallows or allows heating by the heater, based on a result of detection by mark detector (28).

Abstract: A connected oven, including a set of in-cavity sensors and a processor configured to automatically identify foodstuff within the cooking cavity, based on the sensor measurements; and automatically operate the heating element based on the foodstuff identity.

Abstract: Several embodiments include a cooking instrument. The cooking instrument can include a heating system. The heating system can include one or more heating elements capable of emitting wireless energy into the cooking chamber. The cooking instrument can also include a control system. The control system can executing a heating sequence to drive the heating system, detect, based on an output signal of a sensor, a trigger event, and configure the heating system in response to detecting the trigger event.

Abstract: A capsule recognition module for a brewing module for preparing a brewed beverage from a single serve capsule includes: an optical sensor for sensing optical properties of the capsule that is located in a capsule recognition position, a capsule recognition window that is made of a transparent material and is located between the capsule recognition position and the camera, and a fan for generating an air flow from the capsule recognition window towards the capsule recognition position.

Abstract: An oven includes a cooking chamber configured to receive a food product, a user interface configured to display information associated with processes employed for cooking, first and second energy sources, and a cooking controller. The first energy source provides primary heating and the second energy source provides secondary heating for the food product. The cooking controller executes instructions associated with a cooking program directing application of energy to the food product via the first or second energy sources. The cooking controller includes processing circuitry configured to monitor energy added to the food product via the first energy source in accordance with the cooking program, receive an indication of a change to a cooking parameter associated with a second energy source, and determine a modification to the cooking program by employing a modification algorithm based on the cooking parameter change.

Abstract: A plasma processing apparatus includes a mounting table including a lower electrode and an electrostatic chuck, a high frequency power supply electrically connected to the lower electrode, a heater provided in the electrostatic chuck, a heater power supply for supplying a power to the heater, a filter unit including a filter connected to the heater power supply, a rod-shaped power feeder connecting the heater power supply and the heater via the filter, an insulating tubular portion having an inner hole through which the power feeder extends, and a conductive choke portion serving to suppress a microwave propagating through the tubular portion. The choke portion includes a first portion extending from the power feeder in a direction intersecting with a longitudinal direction of the power feeder and a cylindrical second portion extending, between the tubular portion and the power feeder, from a peripheral portion of the first portion.

Abstract: A device for analyzing the composition of the contents of a container. The device includes a transmitter/receiver with an electromagnetic field having at least several frequencies in a determined frequency range, a container support for a container (R) whose contents are to be analyzed. The support is adapted to ensure precise relative positioning between the transmitter/receiver and the container (R). A measuring unit measures the complex impedance of the transmitter/receiver influenced by the load constituted by the container (R) and its contents. A spectral analyzer analyzes the contents of the container for measuring the absorption of waves by the container and its contents. An information providing unit provides information relative to the nature of the contents of the container (R) as a function of the complex measured impedance and of the absorption measuring.

Abstract: A domestic appliance with timer control for the treatment of contents, the domestic appliance comprising a timer configured to track a treatment time period, a display configured to display a plurality of screens, at least one user input component programmed to receive a treatment time input corresponding to a treatment time and receive an expiration function input corresponding to an expiration function subsequent to receiving the treatment time input, and a controller programmed to set the timer with the treatment time in accordance with the received treatment time input and set the expiration function.

Abstract: A cooking device has a casing 1, a heating chamber 8 provided in the casing 1, an exhaust tube 18 for guiding exhaust from inside of the heating chamber 8 through an electric component chamber 9 in the casing 1 to front face side, and a dew receiving container 4 that is provided on front face side of the casing 1 and that receives and diffuses the exhaust from the exhaust tube 18 to outside of the casing 1.

Abstract: An aspect of the present invention provides a microwave heating device for an object having a plurality of parts, the microwave heating device including: a plurality of antennas which emits microwaves to a heating chamber inside; a sensor which detects information from a block model assigned the information indicating a characteristic of each of the parts; a display and input operation unit configured to receive an input of heating conditions for the object; an electromagnetic field analysis unit configured to derive a heating profile by electromagnetic field analysis based on the information detected by the sensor and the heating conditions inputted to the display and input operation unit, the heating profile including microwave emitting conditions for the object; and a control unit configured to control performance of the microwaves emitted from the antennas based on the derived heating profile.

Abstract: A microwave heating apparatus includes a cavity arranged to receive a load. At least one microwave generator is configured to feed a plurality of microwaves into the cavity. At least one image-capturing device and a control unit is adapted to obtain load volume information of the load within the cavity based on information recorded by the image-capturing device about at least one portion of the load, obtain load density information using at least one of a user input and information recorded by the image-capturing device about at least one portion of the load, determine load mass information based upon the load volume information and the load density information, determine a heating pattern based upon the load mass information and control the at least one microwave generator to provide the heating pattern within the cavity.

Abstract: An apparatus is provided for heating plastics material pre-forms, with a movable carrier on which a plurality of heating devices is arranged; wherein the heating devices are controllable independently of one another and have in each case a heating element as well as at least one regulating element for regulating the heating output; and wherein the heating devices have in each case one heating area inside which the plastics material pre-forms are capable of being heated, as well as a movement device which introduces the plastics material pre-forms into this heating area. Each heating device has associated with it in each case one control device for controlling a heating procedure.

Abstract: A microwave energy delivery and measurement system, including a microwave energy source configured to delivery microwave energy to a microwave energy delivery device, a measurement system configured to measure at least one parameter of the microwave energy delivery device and a switching network configured to electrically isolate the microwave energy source and the measurement system. The measurement system is configured to actively measure in real time at least one parameter related to the microwave energy delivery device.

Abstract: A microwave heating apparatus and a method of heating a load using microwaves is disclosed. The microwave heating apparatus includes a cavity configured to receive a load, a microwave source for generating microwaves and a plurality of transmission lines for guiding the generated microwaves to the cavity. The microwave heating apparatus may also include an electronic device adapted to adjust the impedances of each of the plurality of transmission lines individually, a measuring device adapted to obtain a signal representative of the impedance of each one of the plurality of transmission lines, and a control unit configured to control the electronic device based on the obtained signals. The microwave heating apparatus, as disclosed, provides a microwave heating apparatus configured to heat a load with improved energy efficiency and improved heating evenness.

Abstract: The present disclosure relates to an apparatus for processing objects with RF energy. The apparatus may include a display for displaying to a user an image of an object to be processed, the image including at least a first portion and a second portion of the object. The apparatus may also include an input unit and at least one processor configured to: receive information based on input provided to the input unit; and generate, based on the received information, processing information for use in processing the object to achieve a first processing result in the first portion of the object and a second processing result in the second portion of the object.

Abstract: A microwave oven is provided. A barrier member prevents airflow provided by a fan assembly from being introduced again to the fan assembly. A separation member divides the airflow provided by the fan assembly to cool a first component and a second component. Thus, the components are efficiently cooled.

Abstract: The electrical power supply to a magnetron (M) is regulated as a function of an instantaneous microwave power setpoint by: predetermining and storing (20) a value (?) for the electrical efficiency of the magnetron; inputting (19) a setpoint mean microwave power value, and converting it into a low frequency setpoint instantaneous power signal that is sampled at high frequency; measuring (8, 9) and sampling the instantaneous values of anode current and of the high voltage fed to the magnetron; calculating (10) the difference at a sampling instant (n) between the setpoint instantaneous microwave power and the product of the current multiplied by the high voltage multiplied by the efficiency; determining an instantaneous microwave power value at the consecutive sampling instant (n+1) that is corrected as a function of a predetermined regulation relationship that is valid at said instant (n+1); and converting it into an analog signal representative of the corrected instantaneous microwave power for powering the ma

Abstract: A high frequency heating apparatus of the present invention includes an inverter power supply for driving the high frequency generating device, a holding member for holding the inverter power supply and cooling fan for cooling down the inverter power supply. The holding member is provided with a holding portion for holding the inverter power supply and an air guide portion for guiding cooling air from the cooling fan toward the inverter power supply, and the air guide portion covers the inverter power supply and guides the cooling air in a manner that a semiconductor switching device and a high voltage transformer of the inverter power supply are primarily cooled down.

Abstract: The present invention provides a microwave oven and a method of operating a microwave oven, which minimises user involvement when heating a food item to a desired target temperature. According to the invention, the initial temperature of the food item is measured prior to the heating process, and the required heating time is determined automatically based on the initial temperature, the target temperature, and the amount of food as entered by the user. In order to heat a food item to a desired target temperature, the user only needs to position a container for temperature measurement and enter the amount of food. In particular, the present invention is preferably adapted for heating of baby food, such as baby milk contained in a baby bottle, and in such case the target temperature is preferably preset to about 37° C.

Abstract: A heating apparatus includes an inverter power supply for driving the high frequency generating device, a holding member for holding the inverter power supply and cooling fan for cooling down the inverter power supply. The holding member is provided with a holding portion for holding the inverter power supply and an air guide portion for guiding cooling air from the cooling fan toward the inverter power supply, and the air guide portion covers the inverter power supply and guides the cooling air in a manner that a semiconductor switching device and a high voltage transformer of the inverter power supply are primarily cooled down.

Abstract: A toaster-cum-microwave oven includes a toasting chamber, a heating device, a humidity measuring device for measuring an inside humidity of the toasting chamber and producing a humidity signal indicating the measured inside humidity, a switching device for selectively cutting or allowing a power supply to the heating device, and a controlling device. The controlling device receives the humidity signal, calculates a rate of change of humidity using the humidity signal, compares the rate of change of humidity with a predetermined value, and controls the switching device to cut the power supply to the heating device after a remaining cooking time has lapsed if the rate of change of humidity is equal to or greater than the predetermined value.

Abstract: A microwave oven, having a humidity sensor and a voltage detecting unit for detecting a change in an output voltage of the humidity sensor, includes: a control unit for receiving a compensated voltage according to a change in temperature supplied from the humidity sensor and a detected voltage supplied from the voltage detecting unit, and determining a cooking time based on a voltage difference between the detected voltage and the compensated voltage. With this configuration, an optimal cooking time based on a being cooked can be calculated by use of the humidity sensor, and the cooking time can be controlled in a stable manner relative to external noise or irregular changes in humidity.

Abstract: A method of controlling a microwave oven, in which the microwave oven includes a cooking chamber for containing food therein, a cooling fan which circulates air, a magnetron which generates microwaves and a humidity sensor which senses humidity of the cooking chamber. Cooking instruction(s) may be preset or set manually by a user. A first cooking operation is performed according to the set cooking instruction(s). A cook time required to perform a second cooking operation is set based on a time required to perform the first cooking operation. The second cooking operation is performed for the cook time while controlling the output power of the magnetron to perform a rapid cooking operation.

Abstract: A method of controlling a microwave oven, in which the microwave oven includes a cooking chamber for containing food therein, a cooling fan which circulates air, a magnetron which generates microwaves and a humidity sensor which senses humidity of the cooking chamber. Cooking instruction(s) may be preset or set manually by a user. A first cooking operation is performed while preventing water from boiling off/to overflow by controlling an output power of the magnetron according to the set cooking instruction(s). A time required to perform a later cooking is set according to a time required to perform the first cooking operation. A second cooking operation is performed for the later cook time while controlling the output power of the magnetron to reduce the overall cook time of the food.

Abstract: A method of controlling a microwave oven, in which the microwave oven includes a cooking chamber for containing food therein, a cooling fan which circulates air, a magnetron which generates microwaves and a humidity sensor which senses humidity of the cooking chamber. Cooking instruction(s) may be preset or set manually by a user. A first cooking operation is performed while preventing water from boiling off/to overflow by controlling an output power of the magnetron according to the set cooking instruction(s). A time required to perform a second cooking operation is set based on a time required to perform the first cooking operation. The second cooking operation is performed for the second cooking time while steam boiling the food.

Abstract: A microwave oven having an improved air outlet and humidity sensor mounting structure includes a body partitioned in its interior into a cooking cavity and a machine room, and a cooling fan installed in the machine room which draws atmospheric air into the cooking cavity while cooling a variety of elements installed in the machine room. In the microwave oven, an air outlet unit discharges air from the cooking cavity, and the humidity sensor senses a cooking atmosphere of the cooking cavity. This microwave oven further comprises a control unit which determines the conditions of food in response to automatically or manually inputted information, and controls the rpm of the cooling fan in response to the determined conditions of the food so as to improve the sensing performance of the humidity sensor.

Abstract: This invention provides a high-frequency heating apparatus for heating by using magnetron including an inverter power supply as a magnetron-driving power supply, a cooling fan, and an air guide. The cooling fan is inclined against the vertical direction of the power supply and fitted to the air guide. This structure increases the cooling effect of the power supply. Additionally, the power supply includes temperature sensors provided on semiconductor elements and a controller for controlling the power supply and an operation of the heating apparatus according to the result of the sensors. These sensors avoid breaking down of the power supply caused by overheating.

Abstract: A process for controlling a cooking operation in a microwave oven as well as a microwave oven therefor. Subsequent to a heating step at full power for bringing cooking liquid to the boil, foodstuff which is to be cooked is added, whereupon continued moisture sensor controlled heating begins, initially at full power, until boiling resumes, whereupon moisture sensor controlled simmering/boiling takes place during a cooking time. During an initial time period of the continued moisture sensor controlled heating, the moisture sensor action is inhibited.

Abstract: A convection cooking appliance includes an oven cavity surrounded by an air channel assembly. The appliance includes heating units and a microwave generator arranged in the air channel assembly. A blower assembly is provided to generate a recirculating flow of air through the air channel assembly and the oven cavity. A controller, responsive to operator inputs, as well as signals from both temperature and pressure sensors located in the air channel assembly, regulates the activation/deactivation state of each of the components. One of the heating units in the air channel assembly is preferably constituted by an open coil heating element which is de-activated when the pressure is sensed to be below a specified threshold.

Abstract: A microwave polymerization system for dentistry utilizes specifically controlled microwave energy to cure polymer materials so as to produce dental prosthetics, such as dentures, bridges and crowns, that are made in an extra-oral setting such as a dental laboratory or dental office, and to create dental composites for fillings and veneers that are used in an intra-oral setting directly in the patient's mouth. Unlike the microwave energy delivered by commercial microwave ovens, the system utilizes metered and controlled microwave energy that is preferably continuous and voltage controlled, and regulates the application of this microwave energy by use of various feedback and control mechanisms. The metered and controlled microwave energy enables a higher degree of conversion of monomers into polymer chains in the polymerization process, thereby enhancing the physical and biocompatibility characteristics of both dental prosthetics and dental composites made from polymers.

Abstract: The device for controlling a cooking area on a glass-ceramic cooking surface includes an inductive cooking utensil detection device for detecting a cooking utensil on the cooking area and a temperature measurement device for measuring a temperature of the cooking surface. The cooking utensil detection device includes an outer conductor track (1) and an inner conductor track (3) nested within said outer conductor track. The temperature measurement device also includes the same outer conductor track (1) and the inner conductor track (3), so that the total number of device components is minimized. The outer conductor track (1) includes, or is supplemented by, a conductor track section (2) extending from it into a center part of the cooking area (4). The cooking utensil detection device and the temperature measurement device can operate utilizing the same outer and inner conductor tracks by time-lagged interrogation or with detection signals at different frequencies.

Abstract: A food amount detector for automatically detecting the amount of a food placed in a cooking chamber of a microwave oven, a microwave oven employing the food amount detector, and control method thereof. Output voltage of a microwave generator is detected while the microwave oven is driven, and the amount of the food placed in the cooking chamber of the microwave oven is determined based on the output voltage such detected. In accordance with the amount of the food such determined, the food is cooked under the appropriate driving conditions of the microwave oven. Accordingly, the user does not need to determine the amount of the food by himself, or set the driving conditions of the microwave oven such as cooking time, level of microwave energy, etc. As a result, the user finds it convenient when using this microwave oven, and the food is cooked under the exact driving conditions set by the microwave oven.

Abstract: A microwave polymerization system for dentistry utilizes specifically controlled microwave energy to cure polymer materials so as to produce dental prosthetics, such as dentures, bridges and crowns, that are made in an extra-oral setting such as a dental laboratory or dental office, and to create dental composites for fillings and veneers that are used in an intra-oral setting directly in the patient's mouth. Unlike the microwave energy delivered by commercial microwave ovens which is controlled by pulsing a maximum voltage pulse on and off at a given duty cycle, the system utilizes metered and controlled microwave energy that is preferably continuous and voltage controlled, and regulates the application of this microwave energy by use of various feedback and control mechanisms.

Abstract: A volatiles analyzer is disclosed that includes a source of microwave radiation that can selectively produce at least one predetermined frequency of microwave radiation. A cavity is in communication with the source. The analyzer includes an analytical pan balance with at least its balance pan in the cavity. The walls of the cavity form a polyhedron that focuses microwave energy of the predetermined frequency on the balance pan while supporting a plurality of TM and TE modes in the cavity.

Abstract: A control system for a blind microwave radiation tool a workpiece is described. The controlled system automatically tunes the cavity containing the workpiece. The control system automatically controls the temperature of the workpiece according to a predetermined temperature versus time schedule. Control system automatically determines when the workpiece has reached a particular predetermined physical condition. To achieve these results the control system automatically monitors applied power, reflected power or current temperature and automatically controls the microwave cavity volume and shape and launch structure including antennae location, cavity short location, cavity diameter, coupling loop position, etc. in order to maintain the cavity in resonance and to determine when to exit without operator intervention.

Abstract: The method is for the control of an electrical oven and includes taking into account the temperature and/or the humidity level of the air measured by sensors in the interior of a cavity of an oven in which food to be heated and/or cooked is placed. The instantaneous value of the supplied power of the magnetron of the oven and the duration of a heating cycle are controlled, such as by fuzzy logic.

Abstract: The magnetron driving control apparatus of a microwave oven and a method thereof by which voltage at output side of a high voltage transformer and voltage of a magnetron are detected by a first and second voltage detecting units and a cooking process status is discriminated according to changes of the voltage at the output side of the high voltage transformer and the voltage of the magnetron to control the driving of the magnetron, such that foodstuff is optimally cooked and an automatic cooking is performed without installment of high priced sensors to thereby reduce the manufacturing cost.

Abstract: An oven and a vessel having a food-stuff or beverage in it cooperate to provide optimum operation of the oven to cook or heat the food-stuff or beverage. The vessel is dimensioned to fit within the oven and has an information carrier for indicating the temperature of the food-stuff or beverage within the vessel by changing color, and a separate identification marking. A detector within the oven detects the identification marking and activates a control device for the oven if at least one predetermined identification requisite from the identification marking is met. The identification marking preferably is a hologram which may be visible, or invisible, to the naked human eye. A separate non-temperature sensitive mark may be provided on the vessel and is sensed by a separate sensing device to allow the oven to start operation.

Abstract: A microwave system is provided which is capable of performing both open and closed vessel microwave chemistry in an efficient and productive manner. For open vessel chemistries, such as digestions, the system offers a microwave oven with: liquid cooled refluxing of samples; reagent dispensing, and temperature control. The open vessel module can quickly and easily be interchanged with a high pressure module capable of operating at pressures in excess of 600 psi.

Abstract: A method for controlling a heating procedure in an oven by using an optically readable information carrier with or on the heating object. The oven may be provided with an optical reading device for touchless reading of the information carrier before and/or during the heating. By providing the information carrier with one or more fields that exhibit color shift at temperatures at will, a feed-back control of the procedure is made possible with simple technical solutions. The special feature of the method is the use of an additional information field for control of the start of the oven.

Abstract: The present invention provides a method and apparatus for agitation-free, low temperature drying of fragile, temperature sensitive, granular materials at atmospheric pressure using Radio Frequency (RF) energy to provide the heat of evaporation. A relatively low velocity flow of purge air through either a continuously moving or stationary product bed provides means for removing moisture from the product at atmospheric pressure. The purge air is maintained at a controlled humidity, temperature and velocity, and the intensity of the RF field is controlled in response to temperature sensing means to control the temperature of the product. For the case of a continuously moving product bed the RF applicator is preferably divided into multiple zones, which may be independently controlled, to effect control of the moisture and temperature profile of the product as it passes through the apparatus.

Abstract: In the operation of a thoroughly heating course of a microwave oven, when an ordinary temperature food having a weight of less than 500 g is heated to a desired finishing temperature of 75.degree. C., heating is performed until the temperature of the food reaches 75.degree. C. by a normal output of 650 W (a first mode). After time t.sub.1 at which 75.degree. C. is reached, the food is heated and kept warm at 90.degree. C. higher than 75.degree. C. by a lower output of 350 W (a second mode). As a result, the food can be surely and thoroughly heated to the inside.

Abstract: Method and microwave oven for controlled boiling of a foodpiece. The foodpiece is heated rapidly into reliable boiling by a supply of maximum microwave power, thereafter a desirable degree of boiling (H.sub.eb) is carried out during a predetermined boiling time (T.sub.b) while controlling the supplied microwave power level dependent on feed-back information (HUM) from a sensor. The boiling procedure is carried out fully automatically with consequently increased user security, decreased energy consumption and improved boiling quality.

Abstract: A control system for a blind microwave radiation tool a workpiece is described. The controlled system automatically tunes the cavity containing the workpiece. The control system automatically controls the temperature of the workpiece according to a predetermined temperature versus time schedule. Control system automatically determines when the workpiece has reached a particular predetermined physical condition. To achieve these results the control system automatically monitors applied power, reflected power or current temperature and automatically controls the microwave antennae location and the cavity short location in order to maintain the cavity in resonance and to determine when to exit without operator intervention. Control system can run on a small computer and is useful for automatically curing polyamic acid to polyimide to a predetermined percent cure automatically without operator intervention.

Abstract: A uniform heating apparatus for a microwave oven and a method thereof which are capable of more uniformly heating food by generating various resonant modes based on the kind of food. The apparatus includes an oscillator unit having a wave guide tube for guiding microwaves generated by a magnetron to a lower portion of a heating chamber formed in a microwave oven main body, a resonant mode conversion unit for converting the microwaves guided to the lower portion of the heating chamber to have various resonant modes, a plurality of sensors for detecting the characteristics of food when the microwaves, the resonant mode of which is converted by the resonant mode conversion unit, are supplied to the food in the heating chamber, and a controller for controlling the oscillator unit and the resonant mode conversion unit in accordance with the characteristics of the food detected by the sensors.

Abstract: After the initial temperature T0 of a heating chamber is sensed (S34), heating by microwaves is conducted until the sensor output of a humidity sensor exhibits a prescribed humidity change amount of 1.0 V (S35-S39). Then, an additional time period is operated based on initial temperature T0 and a time period passed for the elevation of 1.0 V (S40-S42, S50). Heating by microwaves is conducted for the additional time period (S43, S51), and then heating by a heater is conducted. As a result, the moisture included in the food is evaporated and finished crisp. In other words frozen precooked food may be thawed and cooked into a tasty state.

Abstract: A method for automatically controlling cooking by using a vapor sensor in a microwave oven is disclosed. The method for automatically controlling cooking air-cools the cavity for a predetermined time by means of the driving of a fan motor during the automatic cooking operation, and respectively compares magnitude and phase of a signal-processed detecting signal supplied from a detecting signal processing circuit section with magnitude of reference detecting signal and values of reference phases in order to discriminate the polarity of the signal-processed detecting signal. Also, the executing time of the air-cooling operation related to a cooking chamber, which is additionally provided in response to the discriminated polarity, is discriminately adjusted.

Abstract: A method for controlling cooking by using a vapor sensor in a microwave oven measures and records a magnitude of a detecting signal from the vapor sensor in response to water vapor generated from food subjected to heating. When the temperature of food is judged to exceed a predetermined temperature on the basis of the measured magnitude of the detecting signal, a control section compares the average magnitudes of the detecting signals from the vapor sensor with reference magnitudes to judge whether the temperature of food subjected to heating corresponds to a reasonable temperature. If the temperature of food is lower than the reasonable temperature, the food is additionally heated for a preset time. Thus, the outputs of the vapor sensor varied according to the sizes of containers filled with food are selectively controlled to prevent the malfunction of the vapor sensor caused by the different sizes of containers.