Microwave oven

Abstract

Disclosed is a microwave oven provided with: a heating chamber ( 2 ) for housing the object to be cooked therein; a magnetron ( 7 ) that oscillates by having a voltage applied thereto, and generates a microwave to be supplied to the heating chamber ( 2 ); a radio wave sensor ( 11 ) for detecting the microwave generated by the magnetron ( 7 ); a timer ( 15 ) for measuring an oscillation starting time that is a period of time from when the voltage is applied to the magnetron ( 7 ) to when the microwave is detected by the radio wave sensor ( 11 ) due to the oscillation; and a notification unit ( 6 ) for sending a notice about the timing at which the magnetron ( 7 ) should be exchanged. When the oscillation starting time becomes longer than a prescribed period of time, a notice about that fact is sent by the notification unit ( 6 ).

The invention claimed is:  
     
       1. A microwave oven, comprising:
 a heating chamber in which a cooking object is to be placed; 
 a magnetron which oscillates in response to application of voltage thereto to thereby generate a microwave to be supplied into the heating chamber; 
 an electric wave sensor which detects the microwave generated by the magnetron; 
 a timer which counts oscillation start-up time and cumulative driving time of the magnetron, the oscillation start-up time starting when the voltage is applied to the magnetron and ending when the microwave generated by oscillation of the magnetron is detected by the electric wave sensor; and 
 a notification portion which makes a notification concerning time to replace the magnetron, 
 wherein 
 the notification portion is programmed to make the notification when the oscillation start-up time read from the memory portion exceeds a predetermined length of time set based on the cumulative driving time; 
 the oscillation start-up time and the cumulative driving time are readably stored in a memory portion, 
 statistical data of the oscillation start-up time observed when lives of magnetrons come to an end is acquired in advance and stored in the memory portion, and 
 the predetermined length of time is set based on the statistical data read from the memory portion. 
 
     
     
       2. The microwave oven according to  claim 1 ,
 wherein 
 the oscillation start-up time is stored; and 
 the notification portion makes the notification if the oscillation start-up time exceeds the predetermined length of time a plurality of times in a row. 
 
     
     
       3. The microwave oven according to  claim 1 ,
 wherein 
 a plurality of magnetrons are provided as the magnetron; and 
 the magnetrons each oscillate in different phases. 
 
     
     
       4. The microwave oven according to  claim 2 ,
 wherein 
 a plurality of magnetrons are provided as the magnetron; and 
 the magnetrons each oscillate in different phases. 
 
     
     
       5. The microwave oven according to  claim 2 ,
 wherein 
 the timer counts driving time of the magnetron; 
 the oscillation start-up time and cumulative driving time of the magnetron are readably stored.