Abstract:
A nonvolatile semiconductor memory device which is superior in writing and charge holding properties, including a semiconductor substrate in which a channel formation region is formed between a pair of impurity regions formed with an interval, and a first insulating layer, a floating gate, a second insulating layer, and a control gate over an upper layer portion of the semiconductor substrate. It is preferable that a band gap of a semiconductor material forming the floating gate be smaller than that of the semiconductor substrate. For example, it is preferable that the band gap of the semiconductor material forming the floating gate be smaller than that of the channel formation region in the semiconductor substrate by 0.1 eV or more. This is because, by decreasing the bottom energy level of a conduction band of the floating gate electrode to be lower than that of the channel formation region in the semiconductor substrate, carrier injecting and charge holding properties are improved.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a drum type washing machine, and more particularly, to a drum type washing machine having a short time for drying laundry and a drying method thereof. 
         [0003]    2. Description of the Related Art 
         [0004]    Generally, a drum type washing machine is designed such that a cylindrical drum in a washing tub is rotated to drop laundry from the upper side of the drum to the lower side of the drum to wash the laundry during the rotation of the drum. 
         [0005]    The drum type washing machine has properties such that damage of the laundry caused by tangling of the laundry is relatively less than that in a pulsator type washing machine and an agitator type washing machine and the quantity of washing water used in washing the laundry is relatively less than that in the pulsator type washing machine and the agitator type washing machine. 
         [0006]    The drum type washing machine dries the laundry that is completely washed using a dryer including a drying heater and a blower fan and a condenser for, removing moisture in air by condensing humidity in air. The drying process is as follows. 
         [0007]      FIG. 1  is a flowchart illustrating a drying cycle of a conventional drum type washing machine. 
         [0008]    In the conventional drying method of the drum type washing machine, as shown in  FIG. 1 , when a user selects a drying mode using a mode selection key (not shown) of a key panel installed in the drum type washing machine (S 10 ), whether or not a whole washing cycle, including a washing cycle, a rinsing cycle, and a dehydrating cycle, is finished, is determined (S 20 ). 
         [0009]    At this time, if the whole washing cycle is not yet finished, the remaining cycle is continued, or if the whole washing cycle is finished, the drying cycle starts. 
         [0010]    In the drying cycle, air in the drum is heated by the drying heater of the dryer, the heater air is circulated within the drum by the blower fan (S 30 ) such that the high-temperature dry air contacts the laundry to evaporate moisture contained in the laundry, resulting in drying the laundry. 
         [0011]    Simultaneously, the humidity, contained in the air due to moisture separated from the laundry, is condensed by condensing water introduced into the condenser (S 40 ) and is exhausted out of the drum type washing machine (S 50 ). 
         [0012]    Since air in the drum is heated and circulated during the drying of the laundry, the conventional drying method can increase drying efficiency of the laundry and it is possible to prevent undesired power consumption and excessive use of condensing water. 
         [0013]    However, since the laundry is always dried at the same temperature in the conventional drying method, the laundry may be damaged as the drying cycle is carried out when the laundry is dried at high temperature, and it may take a long time for drying laundry when the laundry is dried at low temperature. 
         [0014]    Moreover, since when the laundry is completely dried cannot be detected, the drying cycle may be finished before the drying of laundry is not yet finished, resulting in incomplete drying of the laundry. Otherwise, the drying cycle is continued even after the drying is finished so that the laundry may be damaged. 
         [0015]    Thus, in order to prevent laundry from damage, the conventional drying method dries the laundry at low temperature and as a result, it takes a long time to dry laundry. Moreover, the laundry may be incompletely dried so that the drying efficiency may be deteriorated. 
       SUMMARY OF THE INVENTION 
       [0016]    Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a drying method of a drum type washing machine of controlling temperature of air supplied into a drum, RPM of the drum, and switching a drying heater on or off according to the temperature of air to reduce time for drying laundry and a drum type washing machine using the same. 
         [0017]    It is another object of the present invention to provide a drying method of a drum type washing machine of preventing laundry from damage due to heat of air and reducing power consumption by switching a heater on or off and a drum type washing machine using the same. 
         [0018]    In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of a drum type washing machine including a tub including a drum into which laundry is put, a drum motor for rotating the drum, a drying duct installed to communicate with the tub and to provide a path through which air, heated by a drying heater that is installed therein, flows, a blower installed at a side of the drying duct to supply air heated by the drying heater to the tub through the drying duct, a first temperature sensor installed in the drying duct to detect temperature of air to be supplied to the tub, and a microcomputer for dividing the temperature of air in the tub during a drying cycle into a first temperature range and a second temperature range, maintaining the temperature of air to be supplied to the tub within the first and second temperature ranges by controlling the drying heater during drying processes corresponding to the first and second temperature ranges, and controlling an RPM of the drum motor, when the first temperature sensor detects temperature of the drying duct. 
         [0019]    Moreover, the drum type washing machine further includes a condenser for supplying condensing water to a wall of a condensing duct disposed between the tub and the blower to condense water vapor, in the wet condensing duct, formed during the drying cycle, and the first temperature sensor is installed at a side of the tub. 
         [0020]    Additionally, the drum type washing machine further includes a second temperature sensor for detecting temperature in the tub and outputting the detected temperature to the microcomputer, wherein the second temperature sensor is installed between the tub and the drum to control the RPM of the drum motor based on the temperature detected by the second temperature sensor. 
         [0021]    A method of drying laundry according a first preferred embodiment of the present invention includes the steps of (1) detecting temperature in a tub by a second temperature sensor for detecting the temperature in the tub when a drying mode is selected, (2) rotating a drum within a first motor driving range for a first predetermined time by a drum motor for rotating the drum when temperature detected by the second temperature sensor is less than a reference temperature, and of rotating the drum motor within a second motor driving range after that and heating and supplying air in a drying duct within a first temperature range by a drying heater and a blower which are installed in the drying duct communicated with the tub for a second predetermined time, (3) supplying condensing water to a wall of a condensing duct disposed between the tub and the blower to condense water vapor in the drying duct, when the second predetermined time has elapsed, and (4) rotating the drum within the first motor driving range by the drum motor for the first predetermined time when the second predetermined time has elapsed, and of rotating the drum motor within the second motor driving range and heating and supplying air in the drying duct by the drying heater and the blower for the second predetermined time. 
         [0022]    Preferably, when the temperature, detected by the second temperature sensor for detecting inner temperature of the tub, is equal to or greater than a reference temperature, preferably 50 degrees centigrade, only a sub-step (b) among sub-steps (a) and (b) is carried out. 
         [0023]    Here, the reference temperature is 50 degrees centigrade, the first predetermined time is 10 minutes, the first motor driving range is 1000 RPM to 1200 RPM, the second motor driving range is 40 RPM to 60 RPM, he first temperature range is 110 degrees centigrade to 120 degrees centigrade, and the second temperature range is 95 degrees centigrade to 105 degrees centigrade. 
         [0024]    In the step (2), the drum motor is driven at an allowable maximal RPM of the drum type washing machine. 
         [0025]    Each of methods of drying laundry according to second, third, and fourth preferred embodiments of the present invention includes the steps of (1) detecting temperature of air in a tub including a drum and a drying duct communicating with the tub by a first temperature sensor when a drying mode is selected, (2) controlling a drying heater based on the temperature detected by the first temperature sensor to heat air in the drying duct within a first temperature range and to supply the heated air to the tub using a blower, (3) supplying condensing water to a wall of a condensing duct disposed between the tub and the blower to condense water vapor in the drying duct, and (4) controlling the drying heater based on the temperature detected by the first temperature sensor to heat air in the drying duct within a second temperature range such that the heated air is supplied to the tub by the blower. 
         [0026]    The step (1) includes the sub-step of measuring eccentricity of the drum and performing an detangling cycle when the measure eccentricity is equal to or greater than a predetermined reference eccentricity. 
         [0027]    The step (2) includes the sub-steps of (a) driving a drum motor for rotating the drum within a first motor driving range, and (b) driving the drum motor within a second motor driving range. The step (1) further includes the sub-steps of measuring the quantity of laundry when a completely drying mode is selected from the drying modes and the sub-step (a) is finished, and of estimating and displaying an expected remaining time of a drying cycle according to the measured quantity of laundry. 
         [0028]    Preferably, in the step (2), when temperature, detected by a second temperature sensor for detecting inner temperature of the tub, is equal to or greater than a reference temperature, preferably 50 degrees centigrade, only the sub-step (b) among the sub-steps (a) and (b) is carried out. 
         [0029]    Moreover, in the step (2), a slope with respect to temperature change in the tub, which is detected by the second temperature sensor for detecting the inner temperature of the tub, is estimated, and when the detected slope is equal to or greater than a predetermined reference slope, the step (3) is carried out. 
         [0030]    Preferably, the sub-steps (a) and (b) are carried out for a predetermined time within the first motor driving range and the second motor driving range, respectively. 
         [0031]    Here, the first motor driving range is 1000 RPM to 1200 RPM, the second motor driving range is 40 RPM to 60 RPM, the first temperature range is 110 degrees centigrade to 120 degrees centigrade, and the second temperature range is 95 degrees centigrade to 105 degrees centigrade. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0032]    The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0033]      FIG. 1  is a flowchart illustrating a drying cycle of a conventional drum type washing machine; 
           [0034]      FIG. 2  is a sectional view illustrating a drum type washing machine according a preferred embodiment of the present invention; 
           [0035]      FIG. 3  is a block diagram illustrating the drum type washing machine according to the preferred embodiment of the present invention; 
           [0036]      FIG. 4  is a flowchart illustrating a drying cycle of a drum type washing machine according to a first preferred embodiment of the present invention; 
           [0037]      FIGS. 5 and 6  are flowcharts illustrating respective drying cycles in  FIG. 4 ; 
           [0038]      FIG. 7  is a flowchart illustrating a drying cycle of a drum type washing machine according to a second preferred embodiment of the present invention; 
           [0039]      FIGS. 8 ,  9 , and  10  are flowcharts illustrating respective drying cycles in  FIG. 6 ; 
           [0040]      FIG. 11  is a graph illustrating the relation between temperature and time during the drying cycle of the drum type washing machine according to the second preferred embodiment of the present invention; 
           [0041]      FIG. 12  is a graph illustrating the relation between temperature and time with respect to the quantity of laundry during the drying cycle of the drum type washing machine according to the second preferred embodiment of the present invention; 
           [0042]      FIG. 13  is a flowchart illustrating a drying cycle of a drum type washing machine according to a third preferred embodiment of the present invention; and 
           [0043]      FIG. 14  is a flowchart illustrating a drying cycle of a drum type washing machine according to a fourth preferred embodiment of the present invention. 
       
    
    
     DESCRIPTION OF REFERENCE NUMERALS FOR MAIN COMPONENTS OF THE  DRAWINGS  
       [0000]    
       
           100 : drum type washing machine 
           112 : drying duct 
           114 : air discharging part 
           115 : first temperature sensor 
           116 : condensing duct 
           118 : condenser 
           120 : drier 
           121 : blower 
           122 : drying heater 
           130 : drum 
           131 : tub 
           132 : second temperature sensor 
           140 : drum motor 
           152 : exhaust pipe 
           160 : microcomputer 
           180 : display 
       
     
       DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0060]    Hereinafter, a drum type washing machine and a method of drying laundry according to preferred embodiments of the present invention will be described in detail by reference to the accompanying drawings. 
         [0061]      FIG. 2  is a sectional view illustrating a drum type washing machine according a preferred embodiment of the present invention, and  FIG. 3  is a block diagram illustrating the drum type washing machine according to the preferred embodiment of the present invention. 
         [0062]    The drum type washing machine  100  according to the preferred embodiment of the present invention, as shown in  FIG. 2 , washes laundry by rotating a cylindrical drum within a washing tub and by dropping the laundry from the upper side of the drum to the lower side of the drum. The drum type washing machine  100  includes a housing  111  for forming an external appearance of the drum type washing machine  100 , a tub  131  installed in the housing  111 , a drum  130  rotated within the tub  131  to serve as the washing tub, a drum motor installed in the rear side of the drum  130  to rotate the drum  130 , a drier  120  for drying the laundry, and a condenser  118  for removing moisture contained in internal air. 
         [0063]    Above the tub  131 , a washing water supplying pipe  105  is provided to supply washing water from the exterior, and the washing water that is supplied through the washing water supplying pipe  105  is supplied into the tub  131  via a detergent container  106  for accommodating detergent. In the lower side of the tub  131 , an exhaust pump  151  and an exhaust pipe  152  are provided to exhaust the washing water, used during the washing process, to the exterior. Moreover, in order to put or withdraw the laundry into or from the drum  130 , a door  102  is installed in the front side of the drum type washing machine  100 . Here, the front side means the left side in  FIG. 2  and the rear side means the right side in  FIG. 2 . 
         [0064]    Meanwhile, although not depicted in the drawings, in the circumference and the rear side of the drum  130 , a plurality of holes is formed such that the washing water and air may flow therethrough. Through the holes formed in the drum  130 , air in the drum  130  flows into a space formed between the drum  130  and the tub  131 . 
         [0065]    In the drum type washing machine  100  according to the preferred embodiment of the present invention, after a washing process is finished by repeating a washing cycle and a dehydrating cycle, the drier  120  jets warm air into the drum  130  to dry the laundry. In other words, the drier  120  heats and circulates air in order to dry the laundry in the drum  130 . 
         [0066]    The drier  120  includes a drying heater  122  as a heating device for heating air and a blower for circulating air heated by the drying heater  122 . The blower includes a blower fan motor (not shown) and a blower fan (not shown). The blower fan motor is driven to rotate the blower fan such that air heated by the drying heater  122  as described above is supplied into the tub  131  via the drying duct  112  when a drying cycle is carried out. 
         [0067]    Moreover, the drier  120  includes a drying duct  112  for providing a path through which the heated air flows into the tub  131  and an air discharging part  114  communicated with the inside of the tub  131 . An end  123  of the drying duct  112  is opened such that the heated air flows into the tub  131 . Here, the end  123  of the drying duct  112  may be installed to allow the heated air to flow into the drum  130 . 
         [0068]    In the drying duct  112 , a first temperature sensor  115  is installed to detect temperature of air heated by the drying heater  112  and to output a detected data to a microcomputer  160  shown in  FIG. 3 . As described above, since temperature of the heater air may be stably and precisely detected at the air discharging part  114 , the first temperature sensor  115  is preferably installed at a side of the tub  131 , that is, a side of the air discharging part  114 . 
         [0069]    Thus, the drying heater  122  and the blower  121  of the drier  120  are turned on or off, according to a control signal outputted from the microcomputer  160  caused by the detected data that is inputted from the first temperature sensor  115 , to perform the drying cycle in the washing machine of the present invention. This will be described in detail with reference to  FIG. 3 . 
         [0070]    Additionally, the drying heater  122  is installed in the drying duct  112  between the blower  121  and an air introducing port  123 . As the drying heater  122 , an electric heater for generating heat using electric current is used, and temperature of the drying heater  122  is controlled by a thermistor  125  that is installed in the air discharging part  114 . 
         [0071]    Meanwhile, during the above-described drying cycle of the laundry, moisture must be removed so that smooth drying can be achieved. If high temperature air contacts a low temperature object, moisture in air is liquefied so that moisture contained in air in the drum  130  is removed. 
         [0072]    The condenser  118  is disposed between the blower  121  and the tub  131  to remove moisture from the heated air using the principle as described above. In other words, the condenser  118  is connected to the washing water supplying pipe  105  that is installed in the upper side of the drum type washing machine  100  through which condensing water, supplied through a condensing water supplying pipe  113 , can flow toward a wall of a condensing duct  116  such that high-temperature-and-high-humidity air in the condensing duct  116  contacts the condensing water with a relative lower temperature so that water vapor is condensed, resulting in removing moisture in the drum  130 . 
         [0073]    Moreover, between the tub  131  and the drum  130 , a second temperature sensor is installed to detect washing temperature. The second temperature sensor  132  detects temperature of air in the tub  131  and outputs detected data to the microcomputer  160 . The microcomputer  160  performs the drying cycle according to the detected data inputted from the second temperature sensor  132 . 
         [0074]    In other words, the drum type washing machine  100  according to this preferred embodiment of the present invention supplies the heated air from the drying duct  112  to the tub  131  for drying the laundry, and air discharged from the tub passes through the condensing duct  116  and meets the condensing water, and then is liquefied into water. The liquefied water is exhausted out through the exhaust pipe  151  via the lower side of the tub  131 . 
         [0075]    Moreover, the drum type washing machine  100  includes an air discharging part  114  for discharging humid air to the exterior. In order to discharge air in the tub  131  to the exterior, a side of the air discharging part  114  is communicated with the tub  131  and the other side  117   a  of the air discharging part  114  is communicated with the exterior. At an end of the other side of the air discharging part  114 , an extension part  117  where a fan (not shown) driven by a motor (not shown) is installed and a filter  119  is installed in the extension part  117 . 
         [0076]    Finally, the display  180  displays key manipulations performed by a user, key manipulation result, and time of manipulation result. In this preferred embodiment of the present invention, the display  180  is structured to display an expected remaining time of the drying cycle that is estimated by the microcomputer  170  such that the user can confirm time of finishing the drying cycle, when the user selects a complete mode among the drying mode through key input section  170 . 
         [0077]    For reference, the drying mode is divided into a complete drying mode and a time drying mode. The complete drying mode is a mode where the drying cycle is continued until the laundry is completely dried, and the time drying mode is a mode where the drying mode is carried out only for a predetermined time. In the complete drying mode, it is advantageous that the drying cycle is carried out until the laundry is completely dried, but it takes a lot of time for the complete drying of the laundry and a great deal of electric power is required. On the other hand, the time drying mode has advantages and disadvantages opposite to those of the complete drying mode. 
         [0078]    The microcomputer  160  of the drum type washing machine, as shown in  FIG. 3 , determines whether or not temperature of air in the tub  131  that is inputted from the second temperature sensor  132  is equal to or greater than a reference temperature when the user selects the drying mode through the key input section  170  of the drum type washing machine  100 . The microcomputer  160  performs the corresponding drying process according to whether or not the inputted air temperature is equal to or greater than the reference temperature, and controls the drum motor  140  and the drier  120  to perform the drying process of the present invention during respective drying processes. 
         [0079]    The operation of the microcomputer  160  will be described in detail with reference to  FIGS. 4 to 11  illustrating the drying method according to the preferred embodiment of the present invention. 
         [0080]    For reference, the drying method of the drum type washing machine according to the preferred embodiment of the present invention is roughly divided into a main drying step and an auxiliary drying step. The preferred embodiments of the present invention will be described in detail according to whether the drum motor  140  is rotated at high speed within a first motor driving range and the drying heater  122  supplies heat simultaneously or for a time interval, based on an allowable current when the user selects the drying mode through the key input section  170 . 
         [0081]    For reference, in a case of rotating the drum motor  140  at high speed within the first motor driving range and supplying heat by the drying heater  122  simultaneously, the allowable current must be 15 A. However, in a case of rotating the drum motor  140  at high speed within the first motor driving range and supplying heat by the drying heater  122  for a time interval, 10 A is sufficient for the allowable current. 
         [0082]    Here, a first preferred embodiment of the present invention of performing the high speed rotation of the drum motor  140  and the heat supply by the drying heater  122  for a time interval will be described with reference to  FIGS. 4 ,  5 , and  6 . 
         [0083]    Moreover, second, third and fourth preferred embodiments of the present invention of simultaneously performing the high speed rotation of the drum motor  140  and the heat supply by the drying heater  122  are carried out differently from each other according to mode selected from the completely drying mode and the time drying mode.  FIGS. 7 to 12  illustrate the second preferred embodiment of the present invention carried out by selecting the completely drying mode,  FIG. 13  illustrates the third preferred embodiment of the present invention carried out by selecting the time drying mode, and  FIG. 14  illustrates the fourth preferred embodiment of the present invention of performing the auxiliary drying step and the main drying step according to a magnitude of a slope by estimating the slope with respect to temperature changes. 
         [0084]    On the other hand, the first preferred embodiment of the present invention can be applied to the completely drying mode and the time drying mode like the second, third, and fourth preferred embodiments of the present invention.  FIG. 4  illustrates the completely drying mode, and the same description as that of the time drying mode will be omitted. 
       1. Embodiment 1 
       [0085]      FIG. 4  is a flowchart illustrating the drying cycle of the drum type washing machine according to the first preferred embodiment of the present invention, and  FIGS. 5 and 6  are flowcharts illustrating respective drying cycles in  FIG. 4 . 
         [0086]    The drying method of a drum type washing machine according to the first preferred embodiment of the present invention is a method in which heat is not applied to the laundry when the drum motor  140  is driven with the first motor driving range, but in which heat is applied when the drum motor  140  is driven within a second motor driving range after that. As shown in  FIG. 4 , the user firstly selects the drying mode through the key input section  170  (S 710 ), and selects the completely drying mode of the drying modes, and then an eccentricity is measured (S 720 ). 
         [0087]    There are several methods of measuring the eccentricity, one of estimating duty of a pulse width modulation (PWM) control signal, and the other one of measuring time required to reach and fall from a specific RPM related to the quantity of laundry and current flowing through the motor. Since these methods can be easily employed by a person skilled in the art, their description will be omitted herein. 
         [0088]    Meanwhile, when the eccentricity is measured, the measured eccentricity is compared with a predetermined reference eccentricity. Whether the measured eccentricity is equal to or greater than the reference eccentricity is determined (S 730 ), and when the measured eccentricity is equal to or greater than the reference eccentricity, a detangling cycle is performed (S 735 ) to adjust the eccentricity. 
         [0089]    On the contrary, when the measured eccentricity is less than the reference eccentricity, the detangling cycle is not carried out and the second temperature sensor  132  detects temperature in the tub  131  (S 740 ) to output the detected data to the microcomputer  160 . The microcomputer  160  determines whether or not the measured temperature in the tub  131  is equal to or greater than a reference temperature, preferably, 50 degrees centigrade, based on the detected data (S 750 ). 
         [0090]    At this time, when the temperature in the tub  131  is less than the reference temperature, the auxiliary drying step (S 760 ) is carried out, but when the temperature in the tub  131  is equal to or greater than the reference temperature, the supplying of condensing water and the exhaust of water (S 770 ) and processes after these processes are carried out. 
         [0091]    Particularly, that the second temperature sensor  132  detects the inner temperature of the tub  131  and the detected temperature is compared with the reference temperature such that the next processes are carried out, is to prevent the laundry from damage when air heated in the auxiliary drying step is supplied because the laundry is sufficiently heated when the inner temperature of the tub  131  is equal to or greater than the reference temperature, and to perform a power failure compensation when the electricity is cut off during the drying cycle. 
         [0092]    For example, since, although the electricity is cut off during the drying cycle, temperature in the tub  131  does not rapidly fall, when temperature detected by the second temperature sensor  132  when the power is supplied again is equal to or greater than the reference temperature, the auxiliary drying step is not carried out and the processes after detecting the quantity of laundry is carried out so that power consumption for repeating the same process can be prevented. 
         [0093]    Additionally, during a first auxiliary drying process, if the user stops the drum type washing machine and commands to perform the drying cycle again, since the inner temperature of the tub  131  is sufficiently high when the auxiliary drying step is carried out at the state where the temperature detected by the second temperature sensor  132  is equal to or greater than the reference temperature, excessive heat is applied to the laundry and as a result of this, the laundry may be damaged. In order to prevent this, when temperature detected by the second temperature sensor  132  is equal to or greater than the reference temperature, the auxiliary drying step is not carried out and the processes after that, that is, the supply of the condensing water and the exhaust of water are carried out. 
         [0094]    Meanwhile, when the inner temperature of the tub  131  is less than the reference temperature, the auxiliary drying step is carried out (S 760 ). In the auxiliary drying step according to the first preferred embodiment of the present invention, differently from those according to the second, third, and fourth preferred embodiments of the present invention which will be described later, the drum motor  140  is driven within a first motor driving range, 1000 RPM to 1200 RPM and a second motor driving range, 40 RPM to 60 RPM for a time interval, and when the drum motor  140  is driven within the second motor driving range, the drying heater  122  and the blower fan are driven within a temperature range where temperature detected by the first temperature sensor  151  is within the first temperature range. 
         [0095]    Meanwhile, the first motor driving range may be variously determined according to models of the drum type washing machine. The first motor driving range is increased as the capacity of the drum type washing machine is increased. Particularly, the drum motor  140  is driven at a maximal RPM allowed in the corresponding drum type washing machine. 
         [0096]    Thus, the drum motor  140  of the drum type washing machine is preferably driven, for example, at the allowable maximal RPM, 1200 RPM when the drum type is of an 11 Kg model, and at 1400 RPM when the drum type washing machine is of a 14 Kg model. 
         [0097]    When the drum motor  140  is driven within the first motor driving range, it is possible to obtain dehydration effect at high speed rotation. However, when the drum motor  140  is driven within the second motor driving range and the drying heater  122  is driven, the laundry is heated to a temperature where the laundry is easily dried. 
         [0098]    In other words, as shown in  FIG. 5 , when the drum motor  140  is driven such that the inner temperature of the tub  131  is maintained within the first motor driving range (S 761 ), whether or not a first predetermined time, preferably, 10 minutes has elapsed is determined (S 762 ), the drum motor  140  is continuously driven within the first motor driving range until the first predetermined time has elapsed. 
         [0099]    At this time, when the first predetermined time has elapsed, the quantity of laundry is detected (S 763 ), and the expected remaining time of the drying cycle is estimated through the detected quantity of laundry and displayed (S 764 ). 
         [0100]    When the expected remaining time of the drying cycle is displayed, the drum motor  140  is driven such that the inner temperature of the tub  131  is maintained within the second motor driving range and the drying heater  122  and the blower fan are driven (S 765 ). 
         [0101]    Simultaneously, time is counted and whether or not a second predetermined time, preferably, 40 minutes has elapsed is determined (S 766 ), and it is continued until the second predetermined time has elapsed. 
         [0102]    When the auxiliary drying step is finished, the supply of condensing water and the exhaust process are started such that the condensing water is supplied through the condensing water supplying pipe  113  to remove moisture contained in air during the condensing process, and the condensed water is exhausted to the exterior through the exhaust pipe  152  via the lower side of the tub  131  (S 770 ). 
         [0103]    When the supply of condensing water and the exhaust process are started, the main drying step is performed (S 780 ). In the main drying step, as shown in  FIG. 6 , the drum motor  140  is driven within the first motor driving range (S 781 ) and whether or not the first predetermined time, 10 minutes, has elapsed is determined (S 782 ) such that the drum motor  140  is driven within the first motor driving range until the first predetermined time has elapsed. 
         [0104]    When the first predetermined time has elapsed, the drum motor  140  is driven within the second motor driving range and the blower fan and the drying heater  122  are driven such that the temperature detected by the first temperature sensor  151  is maintained within the second temperature range (S 783 ). 
         [0105]    The above-described processes are carried out until a specific drying rate where it can be determined that the laundry is completely dried (S 780  to S 790 ). 
         [0106]    Meanwhile, differently from the completely drying mode, since time for drying cycle is predetermined in the drying method according to the time drying mode so that it is not need to estimate the expected remaining time of the drying cycle, the process of detecting the quantity of laundry, estimating and displaying the expected remaining time of the drying cycle is not carried out and a complete drying cycle is finished when the time of the drying cycle has elapsed during the main drying step. 
       2. Embodiment 2 
       [0107]      FIG. 7  is a flowchart illustrating a drying cycle of a drum type washing machine according to a second preferred embodiment of the present invention,  FIGS. 8 ,  9 , and  10  are flowcharts illustrating respective drying cycles in  FIG. 7 ,  FIG. 11  is a graph illustrating the relation between temperature and time during the drying cycle of the drum type washing machine according to the second preferred embodiment of the present invention, and  FIG. 12  is a graph illustrating the relation between temperature and time with respect to the quantity of laundry during the drying cycle of the drum type washing machine according to the second preferred embodiment of the present invention. 
         [0108]    The drying method of a drum type washing machine according to the second preferred embodiment of the present invention includes the steps of selecting the drying mode through the key input section  170  by the user (S 110 ), and measuring the eccentricity when the user selects the completely drying mode of the drying modes (S 120 ). 
         [0109]    As described above, when the eccentricity is measured, the measured eccentricity is compared with the predetermined eccentricity and whether or not the measured eccentricity is equal to or greater than the reference eccentricity is determined (S 130 ). When the measured eccentricity is equal to or greater than the reference eccentricity, the detangling process is carried out (S 132 ) to adjust the eccentricity. 
         [0110]    On the contrary, when the measured eccentricity is less than the reference eccentricity, the detangling process is not carried out. 
         [0111]    Next, the second temperature sensor  132  detects the inner temperature of the tub  131  (S 140 ) and outputs the detected data to the microcomputer  160 . The microcomputer  160  determines whether the detected data, that is, the inner temperature of the tub  131  is equal to or greater than the reference temperature, preferably, 50 degrees centigrade (S 150 ). 
         [0112]    At this time, when the inner temperature of the tub  131  is less than the reference temperature, the first auxiliary drying process is carried out. However, when the inner temperature of the tub  131  is equal to or greater than the reference temperature, the first auxiliary drying process is not carried out and the process of detecting the quantity of laundry (S 180 ) and the processes after that are carried out. 
         [0113]    Particularly, that the second temperature sensor  132  detects the inner temperature of the tub  131  and the detected temperature is compared with the reference temperature such that the next processes are carried out based on the compared result, is to prevent the laundry from damage when air heated in the auxiliary drying step is supplied because the laundry is sufficiently heated when the inner temperature of the tub  131  is equal to or greater than the reference temperature, and to perform a power failure compensation when the electricity is cut off during the drying cycle. 
         [0114]    For example, since, although the electricity is interrupted due to electricity failure during the drying cycle, temperature in the tub  131  does not rapidly fall, when temperature detected by the second temperature sensor  132  when the power is supplied again is equal to or greater than the reference temperature, the first auxiliary drying process is not carried out and the processes after detecting the quantity of laundry are carried out so that power consumption for repeating the same process can be prevented. 
         [0115]    Additionally, during the first auxiliary drying process, if the user stops the drum type washing machine and commands to perform the drying cycle again, since the inner temperature of the tub  131  is sufficiently high when the first auxiliary drying process is carried out at the state where the temperature detected by the second temperature sensor  132  is equal to or greater than the reference temperature, excessive heat is applied to the laundry and as a result of this, the laundry may be damaged. 
         [0116]    In order to prevent this, when temperature detected by the second temperature sensor  132  is equal to or greater than the reference temperature, the first auxiliary drying process is not carried out and the processes after that, that is, the supply of the condensing water and the exhaust of water are carried out. 
         [0117]    Meanwhile, in the first auxiliary drying process (S 160 ), as shown in  FIG. 8 , the drum motor  140  is driven within the first motor driving range, preferably, within 1000 RPM to 1200 RPM and the drying heater  122  and the blower  121  are driven (S 161 ). Here, the drum motor  140  starts to drive within the first motor driving range and as time is simultaneously counted. 
         [0118]    As such, as the drum motor  140  is driven at high speed and the drying heater  122  and the blower  121  are driven, air in the drying duct  112  is heated by the drying heater  122  and the heated air is supplied into the tub  131  through the air discharging part  114  by the blower  121 . 
         [0119]    Thus, since the heated air is supplied while the drum motor  140  rotates at high speed, the washing water is dehydrated from the laundry which is heated at temperature where moisture is easily separated. 
         [0120]    Meanwhile, the first temperature sensor  115  detects temperature of air heated by the drying heater  122  and outputs the detected temperature to the microcomputer  160 . The microcomputer  160  controls the temperature of air heated by the drying heater  122  so as to maintain it within the predetermined first temperature range T 2  to T 1 . 
         [0121]    In other words, the first temperature sensor  115  detects the temperature of air heated by the drying heater  122  and continues to output the detected temperature of air to the microcomputer  160 . The microcomputer  160  determines whether or not the detected data, that is, the detected temperature inputted from the first temperature sensor  115  is greater than the predetermined temperature T 1  (S 163 ). When the temperature of air is greater than the first predetermined temperature T 1 , preferably, 120 degrees centigrade, the microcomputer  160  stops the drying heater  122  (S 165 ) and determines whether the detected data is equal to or less than the second predetermined temperature T 2  after stopping the drying heater  122  (S 167 ). After that, when the air temperature is equal to or less than the predetermined temperature T 2 , preferably, 110 degrees centigrade caused by the stopping of the drying heater  122 , the microcomputer  160  repeats the process of driving the drying heater  122  (S 169 ). Thus, during the first auxiliary drying process, temperature of air supplied to the tub  131  is maintained within the first temperature range T 2  to T 1 , that is, 110 degrees centigrade to 120 degrees centigrade. 
         [0122]    After the beginning of the first auxiliary drying process, whether or not a predetermined time t 1 , preferably, 20 minutes has elapsed is determined, the first auxiliary drying process is continued until the predetermined time t 1  has elapsed. 
         [0123]    For reference, when the first auxiliary drying process (S 160 ) is finished, it is possible to obtain approximately 60% drying effect based on the quantity of 10 Kg of laundry. 
         [0124]    Meanwhile, when the first auxiliary drying process (S 160 ) is finished or temperature of the tub  131  detected by the second temperature sensor  132  is less than the reference temperature, the first auxiliary drying process is not carried out and the process of detecting the quantity of laundry (S 170 ) is carried out. At this time, from experimental data obtained from repeated experiments, the expected remaining time of the drying cycle corresponding to the detected quantity of laundry is estimated and displayed on the display  180  (S 180 ). 
         [0125]    In other words, the quantity of laundry is detected by detecting the humidity of the laundry after driving the drum motor  140  within the first motor driving range. By taking the dehydration rate similarly appeared at a specific RPM into consideration, the drying time at the weight of laundry is displayed as an experimental value to obtain the expected remaining time of the drying cycle. Particularly, the detected quantity of laundry may be used as a reference data by taking the dehydration rate similarly appeared at a specific RPM into consideration when whether or not the laundry is completely dried is checked. 
         [0126]    As such, when the expected remaining time of the drying cycle is displayed, a second auxiliary drying process is carried out as a next process (S 190 ). 
         [0127]    In the second auxiliary drying process (S 190 ), as shown in  FIG. 9 , the drum motor  140  is driven at the second motor driving range, 40 RPM to 60 RPM (S 191 ), and the drying heater  122  and the blower  121  are driven (S 191 ). Here, the drum motor  140  starts to drive within the second motor driving range and simultaneously counts time. 
         [0128]    As such, as the drum motor  140  is driven at low speed and the drying heater  122  and the blower  121  are driven, air in the drying duct  112  is heated by the drying heater  122  and the heated air is introduced into the tub  131  through the air discharging part  114  by the blower  121 . 
         [0129]    Thus, since the drum motor  140  rotates at low speed and the heated air is supplied, the washing water is separated from the laundry and simultaneously temperature is increased to a degree where the moisture is easily extracted from the humid laundry. 
         [0130]    Meanwhile, the first temperature sensor  115  detects temperature of air heated by the drying heater  122  and outputs the detected temperature of air to the microcomputer  160 . The microcomputer  160  controls temperature of air heated by the drying heater  122  to be maintained within the first temperature range T 2  to T 1 . 
         [0131]    In other words, the first temperature sensor  115  detects the temperature of air heated by the drying heater  122  and continues to output the detected temperature of air to the microcomputer  160 . The microcomputer  160  determines whether or not the detected data, that is, the detected temperature inputted from the first temperature sensor  115  is greater than the predetermined temperature T 1  (S 193 ). When the temperature of air is greater than the first predetermined temperature T 1 , the microcomputer  160  stops the drying heater  122  (S 195 ) and determines whether the detected data is equal to or less than the second predetermined temperature T 2  after stopping the drying heater  122  (S 197 ). After that, when the air temperature is equal to or less than the predetermined temperature T 2  caused by the stopping of the drying heater  122 , the microcomputer  160  repeats the process of driving the drying heater  122  (S 199 ) again. Thus, during the second auxiliary drying process, temperature of air supplied to the tub  131  is maintained within the first temperature range, that is, 110 degrees centigrade to 120 degrees centigrade. 
         [0132]    After the beginning of the first auxiliary drying process, whether or not a predetermined time t 2 , preferably, 20 minutes has elapsed is determined, the first auxiliary drying process is continued until the predetermined time t 2  has elapsed. Thus, to carry out the first auxiliary drying process and the second auxiliary drying process, it takes about 40 minutes. 
         [0133]    Here, the reason why the predetermined time t 2  is set to 20 minutes and time until the second auxiliary drying process is finished is set to 40 minutes, is that it takes 40 minutes until the second auxiliary drying process is finished according to a curve of a reference temperature experimentally performed with respect to a general quantity of 10 Kg of laundry. The determined time t 2  can be variously determined. 
         [0134]    As described above, since the drum type washing machine is driven within the first temperature range for the time periods when the first and second auxiliary drying processes are carried out, as illustrated in  FIG. 11 , temperature suddenly rises a little during the predetermined times t 1  and t 2 . On the other hand, in a time period where the main drying step is carried out after that, since the drum type washing machine is driven according to the second temperature range, temperature is maintained to have a relatively slow slope. 
         [0135]    When the predetermined time t 2  has elapsed and the second auxiliary drying process (S 190 ) is finished, the supply of the condensing water and the exhaust of water are carried out. 
         [0136]    The condensing water, as described above, is supplied through the condensing water supplying pipe  113  by a valve for controlling the supply of the condensing water and moisture contained in air is removed during the condensing process. The condensed water is exhausted to the exterior through the exhaust pipe  152  via the lower side of the tub  131 . 
         [0137]    As such, after the beginning of the supply of the condensing water and the exhaust of water, the main drying step (S 210 ) is carried out. 
         [0138]    In the main drying step (S 210 ), as shown in  FIG. 10 , the drum motor  140  is driven within the second motor driving range, preferably, 40 RPM to  60  RPM, and the drying heater  122  and the blower  121  are driven (S 211 ). 
         [0139]    As such, as the drum motor  140  is driven at low speed and the drying heater  122  and the blower  121  are driven, air in the drying duct  112  is heated by the drying heater  122  and the heated air is introduced into the tub  131  through the air discharging part  114  by the blower  121 . 
         [0140]    Thus, the drum motor  140  rotates at low speed and the heated air is supplied. Since the laundry is heated at temperature suitable to dry during the first and second auxiliary processes, the laundry is easily dried. 
         [0141]    Meanwhile, the first temperature sensor  115  detects temperature of air heated by the drying heater  122  and outputs the detected temperature of air to the microcomputer  160 . The microcomputer  160  controls temperature of air heated by the drying heater  122  to be maintained within a second temperature range T 4  to T 3 , preferably, 95 degrees centigrade to 105 degrees centigrade. 
         [0142]    In other words, the first temperature sensor  115  detects the temperature of air heated by the drying heater  122  and continues to output the detected temperature of air to the microcomputer  160 . The microcomputer  160  determines whether or not the detected data, that is, the detected temperature inputted from the first temperature sensor  115  is greater than the predetermined temperature T 3 , that is, 105 degrees centigrade (S 213 ). When the temperature of air is greater than the predetermined temperature T 3 , the microcomputer  160  stops the drying heater  122  (S 215 ) and determines whether the detected data is equal to or less than the predetermined temperature T 4 , that is, 95 degrees centigrade after stopping the drying heater  122  (S 217 ). After that, when the air temperature is equal to or less than the predetermined temperature T 4  caused by the stopping of the drying heater  122 , the microcomputer  160  repeats the process of driving the drying heater  122 . Thus, during the main drying step, temperature of air supplied to the tub  131  is maintained within 95 degrees centigrade to 105 degrees centigrade. 
         [0143]    After the beginning of the main drying step, it is determined whether or not the expected remaining time of the drying cycle, by detecting the quantity of laundry, has elapsed (S 220 ), and the main drying step is continued until the expected remaining time has elapsed. 
         [0144]    Meanwhile, when the expected remaining time of the drying cycle has elapsed, it is determined whether or not a drying rate reaches a specific drying rate indicating the completion of drying. When the drying rate reaches the specific drying rate, the drying cycle is finished. When the drying rate does not reach the specific drying rate, the main drying step (S 210 ) is preferably carried out for a predetermined time, for example, 10 minutes to 20 minutes. 
         [0145]    The drying method according to this preferred embodiment of the present invention, as shown in  FIG. 12 , may be carried out in various ways according to the quantity of laundry. As described above, according to the quantity of laundry, time when the second auxiliary drying process is finished is different from time when the main drying step is started. The slopes with respect to the temperature change during the first and second auxiliary drying processes are different from each other. 
         [0146]    In other words, as the quantity of laundry is small, the slope with respect to the temperature change until the second auxiliary drying process increases and time of starting the main drying step is shortened. 
         [0147]    Particularly, since the expected remaining time is varied according to a range of the respective quantities of laundry, it is possible to determine a completion time A of the drying cycle when the completion of drying is achieved from the above-mentioned graph, that is, the completely drying time can be determined from the time period where temperature suddenly rises after the complete drying. 
       3. Embodiment 3 
       [0148]    Next, a drying method according to a third preferred embodiment of the present invention will be described with reference to  FIG. 13 . 
         [0149]      FIG. 13  is a flowchart illustrating a drying cycle of a drum type washing machine according to the third preferred embodiment of the present invention. 
         [0150]    The drying method of a drum type washing machine according to the third preferred embodiment of the present invention is similar as that according to the second preferred embodiment of the present invention. However, the drying method according to the third preferred embodiment of the present invention relates a drying method in a case of selecting the time drying mode different from the case of selecting the completely drying mode when the user selects the drying mode in the first preferred embodiment of the present invention. 
         [0151]    Thus, it will be described in brief with respect to the same as that in the second preferred embodiment of the present invention, and other aspects will be described in detail. 
         [0152]    Firstly, when the user selects the drying mode (S 310 ) and after that selects the time drying mode, the eccentricity of laundry is measured (S 320 ). When the measured eccentricity is equal to or greater than the reference eccentricity, the detangling cycle is carried out (S 332 ). When the measured eccentricity is less than the reference eccentricity, the detangling cycle is not carried out and the second temperature sensor  132  detects temperature of air in the tub  131  (S 340 ) and outputs the detected temperature. 
         [0153]    It is determined whether or not the temperature detected by the second temperature sensor  132  is equal to or greater than a reference temperature, preferably, 50 degrees centigrade (S 350 ). When the temperature detected by the second temperature sensor  132  is less than the reference temperature, the first auxiliary drying process (S 360 ) is carried out for the predetermined time t 1  within the first motor driving range of 1000 RPM to 1200 RPM (S 360  to S 370 ). 
         [0154]    On the contrary, when the temperature detected by the second temperature sensor  132  is equal to or greater than the reference temperature, the first auxiliary drying process (S 360 ) is not carried out but the processes after the first auxiliary drying process (S 360 ) are carried out. 
         [0155]    Next, the second auxiliary drying process (S 370 ) is carried out. In the second auxiliary drying process (S 370 ), a process of drying laundry is carried out until the predetermined time t 2  has elapsed by driving the drum motor  140  within the second motor driving range, preferably, 40 RPM to 60 RPM and maintaining temperature of air to be supplied to the tub  131  at the first temperature range T 2  to T 1 . 
         [0156]    As such, when the second auxiliary drying process (S 370 ) is carried out, the supply of the condensing water and the exhaust of water are carried out (S 380 ). Simultaneously, the drum motor  140  is driven within the second motor driving range of 40 RPM to 60 RPM and temperature of air to be supplied to the tub  131  is maintained within the second temperature range T 4  to T 3 , preferably, 95 degrees centigrade to 105 degrees centigrade so that the main drying step (S 390 ) of drying laundry is carried out according to the time drying mode until the drying time has elapsed (S 400 ). 
         [0157]    In the drying method according to third preferred embodiment of the present invention, the drying time is set and the drying process is carried out only for the drying time. Thus, the process of obtaining the expected remaining time of the drying cycle by detecting the quantity of laundry is not carried out unlike the second preferred embodiment of the present invention, and it is not determined whether or not the laundry is completely dried. Therefore, when the predetermined drying time has elapsed, the drying process is finished by force. 
       4. Embodiment 4 
       [0158]    A drying method according to a fourth preferred embodiment of the present invention will be described with reference to  FIG. 14 . 
         [0159]      FIG. 14  is a flowchart illustrating a drying cycle of a drum type washing machine according to the fourth preferred embodiment of the present invention. 
         [0160]    In the drying method according to the fourth preferred embodiment of the present invention, when the drum motor  140  is driven without performing the first and second auxiliary drying processes for the predetermined times t 1  and t 2  unlike the second and third preferred embodiments of the present invention, a slope is estimated with respect to temperature change detected by the second temperature sensor  132 , and the first and second auxiliary drying processes are carried out based on the magnitude of the slope and a starting time of the main drying step is determined. 
         [0161]    Particularly, since the drying method according to this preferred embodiment of the present invention can be applied without determining whether the drying mode is the completely drying mode or the time drying mode, the drying method according to this preferred embodiment of the present invention will be described with respect to, for example, a case of selecting the completely drying mode. Since the case of selecting the time drying mode is similar as that of the completely drying mode and has been described in the third preferred embodiment of the present invention, its detail description will be omitted herein. 
         [0162]    In the drying method of a drum type washing machine according to the fourth preferred embodiment of the present invention, as shown in  FIG. 14 , when the user selects the completely drying mode after selection of the time drying mode (S 510 ), the eccentricity is measured (S 520 ) and it is determined whether or not the measured eccentricity is equal to or greater than the reference eccentricity (S 530 ). When the measured eccentricity is equal to or greater than the reference eccentricity, the detangling cycle is carried out (S 532 ). When the measured eccentricity is less than the reference eccentricity, the second temperature sensor  132  detects temperature of air in the tub  131  (S 540 ) and outputs the detected temperature. 
         [0163]    It is determined whether or not the temperature detected by the second temperature sensor  132  is less than the reference temperature, preferably, 50 degrees centigrade (S 550 ). When the detected temperature is less than the reference temperature, the first auxiliary drying process is carried out such that the drum motor  140  is driven within the first motor driving range, that is, at high speed of 1000 RPM to 1200 RPM and temperature of air to be supplied to the tub  131  is maintained within the first temperature range T 2  to T 1 , preferably, 110 degrees centigrade to 120 degrees centigrade (S 560 ). At this time, it is determined whether or not the slope with respect to the temperature change detected by the second temperature sensor  132  is greater than a predetermined reference slope (S 570 ). When the slope is equal to or greater than the reference slope, the first auxiliary drying process is finished and the next processes are carried out. 
         [0164]    On the contrary, when the temperature detected by the second temperature sensor  132  is equal to or greater than the reference temperature, the first auxiliary drying process is not carried out (S 560 ) and the processes after the first auxiliary drying process ($ 560 ) are carried out. 
         [0165]    This is carried out according to features of the laundry, and is because, in a case of putting dry laundry or laundry that is easily dried into the drum, the laundry may be damaged when high temperature air is supplied for the predetermined times t 1  and t 2  like those in the first, second, and third preferred embodiments of the present invention. 
         [0166]    Thus, in this preferred embodiment of the present invention, it is possible to perform the first auxiliary drying process for the predetermined times t 1  and t 2  as well as based on the slope with respect to temperature change. In this case, although the first auxiliary drying process is carried out for the predetermined time t 1 , if the slope with respect to the temperature change is equal to or greater than the reference slope, the first auxiliary drying process is not carried out further and the next processes may be carried out even when the predetermined times t 1  is not elapsed. Thus, by performing the above-mentioned two drying methods, time of the drying cycle can be reduced and the laundry can be effectively dried without damage. 
         [0167]    This is identical to when the second auxiliary drying process is carried out (S 600 ). 
         [0168]    When the first auxiliary drying process (S 560 ) is finished or temperature detected by the second temperature sensor  132  is less than the reference temperature, the first auxiliary drying process ( 9560 ) is not carried out and the process of detecting the quantity of laundry (S 580 ) is carried out. At this time, from experimental data obtained from repeated experiments, the expected remaining time of the drying cycle corresponding to the detected quantity of laundry is estimated and displayed on the display  180  (S 590 ). 
         [0169]    When the expected remaining time of the drying cycle is displayed, the second auxiliary drying process is carried out as a next process (S 600 ). 
         [0170]    In the second auxiliary drying process (S 600 ), it is determined whether or not the slope with respect to the temperature change detected by the second temperature sensor  132  is equal to or greater than the predetermined reference slope (S 610 ), like the first auxiliary drying process. When the slope with respect to the temperature change is less than the reference slope, a process of drying laundry is carried out by driving the drum motor  140  within the second motor driving range, that is, at low speed of 40 RPM to 60 RPM and maintaining temperature of air to be supplied to the tub  131  within the first temperature range T 2  to T 1 . When the slope with respect to the temperature change is equal to or greater than the reference slope, the next processes are carried out. 
         [0171]    Next, the condensing water is supplied through the condensing water supplying pipe  113  to remove moisture contained in air during the condensing process, the condensed water is exhausted to the exterior through the exhaust pipe  151  via the lower side of the tub  131  by performing the supply of condensing water and the exhaust of water (S 620 ). When the supply of condensing water and the exhaust of water are completed, the main drying step (S 630 ) is carried out. 
         [0172]    In the main drying step (S 630 ), the drum motor  140  is driven within the second motor driving range, that is, at low speed of 40 RPM to 60 RPM and temperature of air to be supplied to the tub  131  is maintained within the second temperature range of T 4  to T 3 , preferably, 95 degrees centigrade to 105 degrees centigrade. The main drying step is carried out until the expected remaining time of the drying cycle has elapsed (S 640  to S 650 ). 
         [0173]    Meanwhile, when the expected remaining time of the drying cycle has elapsed, it is determined whether or not a drying rate reaches a specific drying rate indicating the completion of drying. When the drying rate reaches the specific drying rate, the drying cycle is finished. When the drying rate does not reach the specific drying rate, the main drying step (S 630 ) is further carried out for a predetermined time, for example, 10 minutes to 20 minutes (S 640  to S 650 ). 
         [0174]    Drying rates in the first, second, third, and fourth preferred embodiments of the present invention will be described with reference to Table 1 as follows. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Drying rates according to the respective preferred 
               
               
                 embodiments 
               
             
          
           
               
                   
                   
                   
                   
                 Weight 
                   
               
               
                   
                   
                   
                   
                 of 
               
               
                   
                 Weight 
                 Weight 
                   
                 laundry 
               
               
                   
                 of dry 
                 of humid 
                 Drying 
                 after 
               
               
                   
                 laundry 
                 laundry 
                 time 
                 drying 
                 Drying 
               
               
                 Item 
                 (Kg) 
                 (Kg) 
                 (min) 
                 (Kg) 
                 rate (%) 
               
               
                   
               
               
                 Conventional 
                 5.02 
                 9.03 
                 300 
                 5.55 
                 90.45 
               
               
                 art 
               
               
                 Embodiment 1 
                 4.99 
                 9.03 
                 223 
                 5.19 
                 96.05 
               
               
                 Embodiments 
                 5.02 
                 9.03 
                 180 
                 5.25 
                 95.70 
               
               
                 2, 3, 4 
               
               
                   
               
             
          
         
       
     
         [0175]    The drying rates in the drying method according to the preferred embodiments of the present invention and the convention drying method will be described with reference to Table 1. At a state when weight of humid laundry is 9.03 Kg in the respective preferred embodiments of the present invention and in the conventional drying method, the conventional drying method is carried out. At this time, when the drying time of 300 minute has elapsed, weight of dried laundry is 5.55 Kg. Thus, the drying rate indicating weight of laundry after the drying with respect to weight of dry laundry is 90.45%. 
         [0176]    On the contrary, when the drying method according to the first preferred embodiment of the present invention is carried out, weight of laundry after the drying when the drying time of 223 minutes has elapsed is 5.19 Kg and the drying rate is 96.05%. Moreover, when the drying methods according to the second, third, and fourth preferred embodiments of the present invention are carried out, weight of laundry after the drying when the drying time of 180 minutes has elapsed is 5.25 Kg and the drying rate is 95.70%. 
         [0177]    As described above, in comparison to the conventional drying method, when the drying methods according to the preferred embodiments of the present invention are carried out, a great deal of moisture can be removed within a short time so that a high drying rate can be achieved within a short time. 
         [0178]    Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. 
         [0179]    According to the drying method of the present invention, based on temperature of external air to be supplied into the tub, RPM of the drum motor and switching on/off of the heater are controlled to reduce time for drying laundry. 
         [0180]    Moreover, it is possible to prevent laundry from damage due to heat of air in the tub and power consumption can be reduced by switching the heater on/off.