Heat cooker

1. A heat cooker comprising:

a casing;

a heating compartment provided in the casing and having an opening on a front face side to accommodate therein a heating object, which is an item to be heated;

a door for opening and closing the opening of the heating compartment;

a heater to be used for grill heating of the heating object;

a magnetron that generates microwave to heat the heating object;

a steam generator that generates steam to be provided to the heating compartment;

an air supply fan, provided in the casing, for sucking outside air outside the casing and blowing the outside air into the casing;

an air supply passage for allowing the outside air, which is blown out by the air supply fan, to flow there through inside the casing;

a variable-type air supply opening provided in the heating compartment and enabled to bring the outside air within the air supply passage into the heating compartment at an arbitrary ratio wherein the variable type air supply opening includes,

an air supply opening,

an air supply damper having a cam groove formed thereon and pivoting on a pivot,

an air supply damper motor selectively driving a damper cam,

the damper cam including

the cam groove provided on the air supply damper and having an relieved area which extends generally vertically with respect to the pivot, and

a cam shaft inserted into the cam groove and eccentric on the damper cam, the cam shaft rotated about the pivot by the air supply damper motor;

an exhaust opening provided in the heating compartment to discharge smoke within the heating compartment out of the heating compartment;

an exhaust passage for guiding the smoke to outside of the casing; and

a control controlling operation of the variable-type air supply opening, wherein

the control is programmed to:

determine whether the heating object is being heated by the heater and the magnetron, simultaneously, or only by the heater, and

control the variable-type air supply opening so that an openness of the air supply opening becomes a predetermined target openness when only the heater is operating or the heater and the magnetron are operating simultaneously.

2. The heat cooker as claimed in claim 1 , wherein the control unit is further programmed to:

upon an end of the heat cooking, control operation of the variable-type air supply opening so that the openness of the air supply opening becomes larger than the target openness.

3. The heat cooker as claimed in claim 1 , wherein

the control unit controls operation of the variable-type air supply opening so that the openness of the air supply opening becomes the target openness at a time point which is a preset time duration before an end of heat cooking of the heating object.

4. The heat cooker as claimed in claim 1 , wherein

gas blown out into the casing by the air supply fan cools heat generating components in the casing.

5. The heat cooker as claimed in claim 1 , wherein

gas that has flowed through the air supply passage and that has not flowed into the variable-type air supply opening is finally mixed with exhaust gas discharged from the exhaust opening.

6. The heat cooker as claimed in claim 1 , wherein

the exhaust passage guides smoke, which has come out of the heating compartment from the exhaust opening, toward a front face side of the casing.

7. The heat cooker as claimed in claim 1 , further comprising:

a steam generation unit for generating steam to be supplied into the heating compartment.

8. The heat cooker of claim 1 wherein the target openness is within a range of 20% to 60%.

9. The heat cooker of claim 1 wherein the air supply damper motor has an axis of rotation, said cam shaft being offset from the axis of rotation of said air supply damper motor so as to travel in an arc when said air supply damper motor is turned around the axis of rotation.