Drying machine

1. A method of controlling a drying machine, comprising:

a first load decision step for determining, based on a rate of the variation in a temperature of air discharged from a drum, whether a load of clothes accommodated in the drum is a first load size, a second load size, or a third load size, wherein the variation in temperature of air is sensed by a temperature sensor, hot air is supplied to the drum by driving of the drum, a heater, and a fan motor, the third load size is larger than the first load size and the second load size, and the second load size is larger than the first load size;

a second load decision step for determining whether the load of clothes is the first load size or a fourth load size smaller than the first load size using a dryness sensor provided in the drum while the supply of hot air and the driving of the drum has been stopped, the second load decision step being selectively performed after the first load decision step based on the load being determined to be the first load size in the first load decision step; and

a drying step for performing drying based on the determined load size in the first load decision step or the second decision step,

wherein the first load decision step comprises determining that the load of clothes is the second load size or the third load size based on the rate of the variation in the temperature of air being less than a first threshold value,

wherein the first load decision step comprises determining that the load of clothes is the first load size based on the rate of the variation in the temperature of air being greater than or equal to the first threshold value,

wherein the second load decision step comprises determining that the load of clothes is the fourth load based on a frequency of the clothes contact with the dryness sensor being greater than or equal to a reference value, and

wherein the second load decision step comprises determining that the load of clothes is the first load size based on the frequency of the clothes contact with the dryness sensor being less than the reference value.

2. The control method according to claim 1 ,

wherein the supply quantity of heat of the heater and the RPM value of the fan motor are controlled to be constant in the drying step based on the load of clothes being determined to be a first load size or the fourth load size, and

wherein the supply quantity of heat of the heater and the RPM value of the fan motor are controlled to vary in the drying step based on the load of clothes being determined to be the second load size or the third load size.

3. The control method according to claim 1 , further comprising an initial temperature sensing step for sensing a temperature using the temperature sensor before the first load decision step,

wherein the driving of the heater is stopped and the fan motor and the drum are driven in the initial temperature sensing step.

4. The control method according to claim 3 , wherein the first load decision step is performed based on the initial sensed temperature in the initial temperature sensing step being a predetermined temperature or lower than the predetermined temperature,

wherein the initial temperature sensing step is repeated for a predetermined time based on the initial sensed temperature in the initial temperature sensing step exceeding the predetermined temperature, and

wherein, while the initial temperature sensing step is repeated, the first load decision step is performed based on the initial sensed temperature being the predetermined temperature or lower, and the first load decision step is not performed and the second load decision step is performed based on the initial temperature exceeding the predetermined temperature,

wherein the predetermined time is a time to perform a temperature drop when cool air is supplied even if the initial sensed temperature is the highest temperature range and the load of the clothes is of the third load size, and

wherein the predetermined time is a time to perform a temperature drop when cool air is supplied even if the initial sensed temperature is in a highest temperature range and the load of the clothes is of the third load size.

5. The control method according to claim 4 , wherein the initial temperature sensed during first load decision step is categorized into any of a plurality of temperature ranges,

wherein the initial temperature is the lowest temperature in the highest temperature range among the plurality of temperature ranges.

6. The control method according to claim 1 , wherein the first load decision step includes a RPM setting step for setting the RPM of the fan motor to an increased value.

7. The control method according to claim 6 , wherein the RPM stetting step is performed to increase the RPM in a stepwise manner.

8. The control method according to claim 1 , wherein the supply quantity of heat of the heater is controlled to be maximum in the first load decision step.

9. The control method according to claim 1 , further comprising a duct blockage sensing step for sensing duct blockage using an airflow switch, wherein the duct blockage sensing step is eliminated in the first load decision step and the second load decision step, and is performed in performing the drying step.

10. The control method according to claim 1 , further comprising a cooling step for supplying cold air into the drum by driving the drum and the fan motor after the drying step ends, and

wherein the fan motor is controlled to be operated at a previous RPM in cooling step.