Patent Publication Number: US-2019194859-A1

Title: Laundry treatment apparatus and control method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Korean Patent Application No. 10-2017-0181372, filed on Dec. 27, 2017 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
     FIELD 
     The present disclosure relates to a laundry treatment apparatus and a control method thereof. 
     BACKGROUND 
     In general, the term “laundry treatment apparatus” commonly designates various kinds of apparatuses for removing contaminants from clothing, bedding, etc. (hereinafter, referred to as ‘laundry’) using a chemical decomposition action of water and detergent and a physical action, such as friction, between water and laundry. The laundry treatment apparatus is basically configured to have a structure in which a drum for receiving laundry is rotatably installed. The laundry treatment apparatus may be classified as a front loading type laundry treatment apparatus, into which laundry is introduced through an introduction port provided in the front surface thereof, and a top loading type laundry treatment apparatus, into which laundry is introduced through an introduction port provided in the upper surface thereof. 
     The top loading type laundry treatment apparatus includes a cabinet, a tub disposed in the cabinet, the tub being provided in the upper surface thereof with an introduction port, a drum rotatably disposed in the tub, and a door for opening and closing the introduction port. In addition, a door may be disposed at the top of the tub so as to be connected to the tub in order to open and close the open top of the tub, and a top cover may be disposed at the remaining portion of the top of the tub, excluding the portion of the top of the tub at which the door is disposed, in order to cover the tub. 
     In addition, the laundry treatment apparatus further includes a detergent introduction unit for supplying detergent or fabric softener to the tub. When water is supplied into the tub through the detergent introduction unit from the outside, detergent or fabric softener from the detergent introduction unit is introduced into the tub together with the water. 
     In a conventional detergent introduction unit, however, some of the detergent or fabric softener remains in the detergent introduction unit even after water is supplied up to a predetermined level of the tub. 
     Korean Patent Application Publication No. 10-2106-0058737 (2016 May 25) discloses a laundry treatment apparatus including a detergent reception unit and a rotary device rotatably coupled to at least a portion of the detergent movement path such that detergent from the detergent reception unit is supplied in a dissolved state, whereby the detergent is prevented from remaining in the detergent reception unit. 
     In this publication, however, the detergent remaining in the detergent reception unit may not be removed depending on when the supply of water is stopped. 
     If detergent or fabric softener remains in the detergent introduction unit, the detergent introduction unit may be contaminated. In addition, an introduction port, through which detergent or fabric softener is introduced into the tub, may become clogged. 
     SUMMARY 
     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 laundry treatment apparatus that is capable of controlling the supply of water to a detergent introduction unit for receiving detergent or fabric softener in order to remove remaining water from the detergent introduction unit and a control method thereof. 
     In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of a laundry treatment apparatus including a drawer disposed so as to be withdrawn through one side of a cabinet, which is open, the cabinet defining the external appearance thereof, the drawer being open at the top thereof, a tub disposed in the drawer for defining a space for storing wash water, a drum rotatably disposed in the tub, a door for opening and closing the top of the tub, which is open, a top cover for covering the open top of the drawer, the top cover being disposed along the outer circumference of the door so as to be spaced apart from the door by a predetermined distance, a detergent introduction unit formed in the top cover for receiving an additive, a water supply unit for allowing or interrupting the supply of water to the tub or to the detergent introduction unit, and a controller for controlling the rotation of the drum and performing control such that at least some of the water that is supplied to the tub is supplied to the detergent introduction unit, wherein the controller controls the water supply unit such that, while water is supplied to the tub, the supply of the water to the detergent introduction unit is allowed or interrupted, in order to remove remaining water from the detergent introduction unit. 
     In accordance with another aspect of the present invention, there is provided a control method of a laundry treatment apparatus, the control method including determining whether rinsing to be performed is final rinsing at a rinsing step that follows a washing step of separating foreign matter from laundry, supplying water to a tub upon determining that the rinsing to be performed is final rinsing, supplying at least some of the water that is supplied to the tub to a detergent introduction unit, interrupting the supply of water to the detergent introduction unit, repeatedly allowing and interrupting the supply of water to the detergent introduction unit in order to remove remaining water from the detergent introduction unit, and interrupting the supply of water to the detergent introduction unit, supplying water up to a target level of the tub, and completing the supply of water. 
     In accordance with a further aspect of the present invention, there is provided a control method of a laundry treatment apparatus, the control method including supplying water to a tub and to a detergent introduction unit until water in the tub reaches a predetermined water level and stopping the supply of water when the water in the tub reaches the predetermined water level (a first step), interrupting the supply of water to the detergent introduction unit and supplying water to the tub for a first time (a second step), supplying water to the detergent introduction unit and to the tub for a second time (a third step), interrupting the supply of water for a third time (a fourth step), supplying water to the tub and to the detergent introduction unit for a fourth time (a fifth step), and supplying water up to a target level of the tub and completing the supply of water (a sixth step). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       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: 
         FIG. 1  is a perspective view of a laundry treatment apparatus according to an embodiment of the present invention; 
         FIG. 2  is a perspective view of a first laundry treatment apparatus according to an embodiment of the present invention; 
         FIG. 3  is a perspective view showing the state in which a drawer of the first laundry treatment apparatus according to the embodiment of the present invention is withdrawn; 
         FIG. 4  is a sectional view of the first laundry treatment apparatus according to the embodiment of the present invention; 
         FIG. 5  is an exploded perspective view showing a drawer according to an embodiment of the present invention and elements disposed in the drawer; 
         FIG. 6  is a plan view of the drawer according to the embodiment of the present invention; 
         FIG. 7  is a perspective view showing the state in which a door of the drawer according to the embodiment of the present invention is open; 
         FIG. 8  is a perspective view showing a detergent introduction unit of the drawer according to the embodiment of the present invention; 
         FIG. 9  is a sectional view of the detergent introduction unit shown in  FIG. 8 ; 
         FIG. 10  is a reference view illustrating a water supply channel in the drawer according to the embodiment of the present invention; 
         FIG. 11  is a block diagram schematically showing the control construction of the first laundry treatment apparatus according to the embodiment of the present invention; 
         FIG. 12  is a reference view illustrating the principle by which a detergent introduction unit according to an embodiment of the present invention is operated; 
         FIGS. 13( a ) to 14( c )  are reference views illustrating the amount of water that remains in the detergent introduction unit through water supply control according to an embodiment of the present invention; 
         FIGS. 15( a ) and ( b )  are a reference view illustrating a water supply method of the first laundry treatment apparatus according to the embodiment of the present invention; and 
         FIG. 16  is a flowchart showing a control method of the first laundry treatment apparatus according to the embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Advantages, features and methods for achieving those of embodiments may become apparent upon referring to embodiments described later in detail together with the attached drawings. However, embodiments are not limited to the embodiments disclosed hereinafter, but may be embodied in different modes. The embodiments are provided for perfection of disclosure and informing a scope to persons skilled in this field of art. The same reference numbers may refer to the same elements throughout the specification. Hereinafter, embodiments of a laundry treatment apparatus according to the present invention will be described with reference to the accompanying drawings. 
     &lt;First Laundry Treatment Apparatus and Second Laundry Treatment Apparatus&gt; 
       FIG. 1  is a perspective view of a laundry treatment apparatus according to an embodiment of the present invention. 
     The laundry treatment apparatus according to the present invention, which is an apparatus that washes, rinses, spin-dries, or dries laundry, may be configured to include only a first laundry treatment apparatus  100  or to include both a first laundry treatment apparatus  100  and a second laundry treatment apparatus  10  disposed on the first laundry treatment apparatus  100 . 
     Referring to  FIG. 1 , the laundry treatment apparatus according to this embodiment may be configured such that the second laundry treatment apparatus  10  is disposed on the first laundry treatment apparatus  100 . However, this is merely an example. Alternatively, only the first laundry treatment apparatus  100  may be independently provided. 
     The second laundry treatment apparatus  10  may include a second cabinet  20 , which defines the external appearance thereof, and a second door  30  for opening and closing the front of the second cabinet  20 . In addition, the second laundry treatment apparatus  10  may further include a second tub (not shown) disposed in the second cabinet  20  for defining a space for storing wash water, a second drum (not shown) rotatably disposed in the second tub for defining a space for storing laundry, a second water supply unit (not shown) for supplying wash water to the second tub, and a second drainage unit (not shown) for discharging the wash water stored in the second tub out of the second cabinet  20 . 
     &lt;First Laundry Treatment Apparatus&gt; 
       FIG. 2  is a perspective view of a first laundry treatment apparatus according to an embodiment of the present invention.  FIG. 3  is a perspective view showing the state in which a drawer of the first laundry treatment apparatus according to the embodiment of the present invention is withdrawn.  FIG. 4  is a sectional view of the first laundry treatment apparatus according to the embodiment of the present invention.  FIG. 5  is an exploded perspective view showing a drawer according to an embodiment of the present invention and elements disposed in the drawer.  FIG. 6  is a plan view of the drawer according to the embodiment of the present invention.  FIG. 7  is a perspective view showing the state in which a door of the drawer according to the embodiment of the present invention is open. 
     Hereinafter, the first laundry treatment apparatus according to the embodiment of the present invention (hereinafter, simply referred to as a “laundry treatment apparatus”) will be described with reference to  FIGS. 2 to 7 . 
     The first laundry treatment apparatus according to this embodiment includes a cabinet  110 , which defines the external appearance thereof, the cabinet  110  being open at one side thereof, a drawer  120  disposed so as to be withdrawn through the open side of the cabinet  110 , the drawer  120  being open at the top thereof, a tub  170  disposed in the drawer  120  for defining a space for storing wash water, a drum  210  rotatably disposed in the tub  170 , a door  190  for opening and closing the top of the tub  170 , which is open, a top cover  140  for covering the open top of the drawer  120 , the top cover  140  being disposed along the outer circumference of the door  190  so as to be spaced apart from the door  190  by a predetermined distance, and a shock absorption unit disposed at the tub  170  or disposed so as to be opposite the tub  170  for preventing the top cover  140  from contacting the door  190 . 
     The laundry treatment apparatus  100  according to this embodiment may further include a plurality of suspension members (not shown) disposed between the tub  170  and the drawer  120 . One end of each of the suspension members may be connected to the inner upper part of the drawer  120 , and the other end of each of the suspension members may be connected to the outer lower part of the tub  170 . 
     The cabinet  110  defines the external appearance of the laundry treatment apparatus. The cabinet  110  has therein a space for receiving the drawer  120 . The cabinet  110  may have a box shape that is open at the front thereof. 
     The cabinet  110  may be provided in the rear surface thereof with a though-hole, through which a portion of a water supply unit  240  or a drainage unit  250  extends. A separate base  126  may be mounted to the bottom of the cabinet  110 . 
     The drawer  120  is disposed so as to be withdrawn through the front open side of the cabinet  110 . The drawer  120  may be received in the cabinet  110 , or may be disposed such that a portion of the drawer  120  is withdrawn ahead of the cabinet  110 . 
     The drawer  120  has therein a space for receiving the tub  170 . The top of the drawer  120  is open. The drawer  120  is disposed so as to be movable along the inner surface of the cabinet  110 . The drawer  120  includes a drawer body  122 , which defines a space for receiving the tub  170 , the drawer body  122  being inserted into the cabinet, and a drawer panel  124  disposed at the front of the drawer body  122  for opening and closing the open front of the cabinet  110 . 
     Inside the drawer body  122  are formed drawer brackets  130 , to which the suspension members are connected. The drawer brackets  130  are formed at the inner upper part of the drawer body  122  so as to protrude. In this embodiment, four drawer brackets  130  are disposed at respective inner corners of the drawer body  122 . The drawer brackets  130  protrude toward the center of the tub  170 . 
     Each of the drawer brackets  130  is provided with a suspension hole (not shown), which is formed vertically through the drawer bracket  130  such that one end of a corresponding one of the suspension members is inserted into and supported by the drawer bracket  130 . Each of the drawer brackets  130  is provided with a recess (not shown), which extends in one direction in order to guide the insertion of each of the suspension members into a corresponding one of the suspension holes. 
     The drawer panel  124  is disposed such that a portion of the drawer panel  124  is opposite the front edge  112  of the cabinet  110 . The drawer panel  124  is disposed at the front of the drawer body  122 . A portion of the drawer panel  124  may contact the front edge  112  of the cabinet  110  in order to limit the rearward movement of the drawer body  122 . 
     The drawer panel  124  may be provided with a control panel  128  for allowing a control command related to the operation of the laundry treatment apparatus  100  to be input or outputting the operational state of the laundry treatment apparatus  100 . 
     The top cover  140  is disposed at the top of the drawer body  122 . The top cover  140  is provided with an entrance  142 , through which laundry is introduced and removed. The top cover  140  is disposed along the outer circumference of the door  190 , a description of which will follow, so as to be spaced apart from the door  190  by a predetermined distance. When the tub  170  vibrates, the door  190 , which is connected to the tub  170 , may also vibrate. Since the top cover  140  is disposed along the outer circumference of the door  190  so as to be spaced apart from the door  190  by a predetermined distance, the top cover  140  may not be affected by the vibration of the tub  170 . In addition, the top cover  140  may be provided with a water supply through-hole  144 , through which one end of the water supply unit  240  extends. 
     The top cover  140  may be provided in the front thereof with at least one detergent introduction unit  154  for introducing detergent into the tub  170 . In this embodiment, detergent introduction units  154  may be provided at opposite sides of the front of the drawer  120 , which is adjacent to a user when the drawer  120  is withdrawn from the cabinet  110 . The detergent introduction units  154  may be disposed at the front corners of the top cover  140 . Each detergent introduction unit  154  includes an introduction bowl  156  formed in the top cover  140  so as to be recessed downwards. An introduction hole  158 , through which detergent is introduced into the tub  170 , is formed in one side of the introduction bowl  156 . The top cover  140  may be formed at the top of the drawer body  122  so as to protrude in order to secure a storage space in the introduction bowl  156 . 
     Each detergent introduction unit  154  is connected to the tub  170  via a detergent introduction pipe  160 . Consequently, detergent stored in each detergent introduction unit  154  is supplied into the tub via the detergent introduction pipe  160 . 
     The top cover  140  is provided at the outer edge thereof with fastening ribs, which are fastened to the drawer  120 . The top cover  140  is fastened to the drawer panel  124  at the front thereof, and is fastened to the drawer body  122  at the opposite sides and the rear thereof. The side ends and the rear end of the top cover  140  are bent toward the drawer body  122  and are provided with fastening ribs, which are fastened to the drawer body  122 . 
     The top cover  140  covers the remaining portion of the top of the tub  170  excluding the portion of the tub  170  corresponding to the door  190 . The top cover  140  includes a top part  146  formed at the top of the drawer  120  so as to be flat and a curved part  148  bent downwards from the top part  146  so as to be concave toward the door  190 . 
     The top part  146  of the top cover  140  is spaced apart from a door panel  192  of the door  190 , a description of which will follow, by a predetermined distance. The top part  146  is formed at almost the same height as the door panel  192 , and is spaced apart from the door panel  192  by a predetermined distance. The top part  146  of the top cover  140  is formed at almost the same height as the door panel  192  in order to secure a space for temporarily storing detergent to be introduced into the introduction bowl  156  of each detergent introduction unit  154 . 
     The curved part  148  is curved downwards toward the bottom of the door panel  192  and is disposed at the bottom of the door panel  192  so as to cover the top of the tub  170 . 
     The tub  170  defines a space for storing wash water to be used to treat laundry. The tub  170  is disposed in the drawer  120 . The tub has a cylindrical shape that is hollow therein and is partially open at the top thereof. 
     The tub  170  includes a tub body  172 , which defines a space for storing water, the tub body  172  being open at the top thereof, and a tub cover  176 , which defines the top of the tub body  172 . 
     The tub body  172  has a cylindrical shape that is open at the top thereof. The bottom of the tub body  172  is connected to the drainage unit  250 , which drains wash water from the tub  170 . At the outer circumference of the tub body  172  are formed tub brackets  174 , to which the suspension members are connected. 
     The tub brackets  174  are disposed at the lower circumferential surface of the tub  170 . The tub brackets  174  are disposed so as to correspond to the respective drawer brackets  130 . The suspension members are connected to the tub brackets  174  via the drawer brackets  130  of the drawer  120  in order to connect the tub  170  to the drawer  120 . 
     The tub cover  176  is provided with a laundry introduction port  178 , through which the inside of the tub body  172  communicates with the outside of the tub body  172 . The laundry introduction port  178  may be formed at the lower side of the entrance  142 , which is formed in the top cover  140 . The tub cover  176  is provided with a water supply port  180 , through which water is supplied into the tub body  172 . The water supply port  180  may be disposed at the lower side of the water supply through-hole  144 , which is formed in the top cover  140 . 
     The door  190 , which opens and closes the laundry introduction port  178 , is disposed at the upper side of the laundry introduction port  178  of the tub cover  176 . 
     The door  190  is rotatably disposed at the upper side of the tub cover  176 . The door  190  is hingedly fixed to the upper side of the tub cover  176 . The door  190  may open the laundry introduction port  178  of the tub cover  176  such that the inside of the tub body  172  communicates with the outside of the tub body  172 , or may close the laundry introduction port  178  of the tub cover  176  in order to prevent the water in the tub  170  from leaking to the outside. 
     The door  190  includes a door panel  192  for covering the open top of the tub  170 , a sealing member  194  for sealing between the tub  170  and the door  190  when the door  190  closes the laundry introduction port  178  of the tub  170 , and a connection member  196  for hingedly fixing the door panel  192  to the tub  170 , the sealing member  194  being mounted to one side of the connection member  196 . The door  190  may further include a hinge unit  198  disposed at one side of the door panel  192  for hingedly fixing the door panel  192  to one side of the tub cover  176 . The hinge unit  198  may be disposed at one side of the rear of the connection member  916 . 
     The door  190  may further include a fixing member  200  for fixing the door  190  to one side of the tub  170  when the door  190  closes the laundry introduction port  178  of the tub  170 . The fixing member  200  is disposed in front of the connection member  196 . A one-touch click button, which is locked or unlocked by pushing, may be used as the fixing member  200 . 
     The door panel  192  may open and close the laundry introduction port  178  of the tub cover  176 . The door panel  192  is formed so as to be larger than the laundry introduction port  178  of the tub cover  176 . 
     The sealing member  194  is disposed at the lower side of the door panel  192 . The sealing member  194  forms a seal between the door panel  192  and the tub cover  176  when the door  190  closes the laundry introduction port  178  of the tub cover  176 . 
     The drum  210  is rotatably disposed in the tub  170 . The drum  210  has a cylindrical shape that is open at the top thereof. The open top of the drum  210  is disposed at the lower side of the laundry introduction port  178  of the tub  170 . The drum  210  may include a balancer  216  for preventing the drum  210  from vibrating excessively due to the eccentricity of laundry when the drum  210  is rotated by a driving unit  220 . 
     The drum  210  is provided in the bottom surface and the circumferential surface thereof with a plurality of communication holes  212 , through which the inside of the drum  2109  communicates with the tub  170 . The drum  210  is rotated in the tub  1709  by the driving unit  220 . The drum  210  is provided on the bottom surface thereof with at least one washing protrusion  214 , which protrudes from the bottom surface of the drum  210  to generate a water current during the rotation of the drum  210 . 
     The driving unit  220  includes a stator  222 , a rotor  224  configured to be rotated by a rotating field generated by the stator  222 , and a rotary shaft  226  for transmitting the rotational force of the rotor  224  to the drum  210 . 
     The laundry treatment apparatus according to this embodiment further includes a water supply unit  240  for supplying water to the tub  170  and a drainage unit  250  for discharging the wash water stored in the tub  170  to the outside. 
     The water supply unit  240  includes a water supply pipe  242 , which is connected to the water supply through-hole  144  in the tub cover  176 , and a water supply valve  244  for allowing or interrupting the supply of water to the water supply pipe  242 . A portion of the water supply pipe  242  may be formed as a bellows pipe in order to prevent the water supply pipe  242  from being separated from the tub  170  due to the vibration of the tub  170  or such that the length of the water supply pipe  242  is adjustable when the drawer  120  is withdrawn. The top cover  140  may further include a water supply port cover  150  for preventing a portion of the water supply valve  244  from being exposed to the outside when the drawer  120  is withdrawn. 
     The drainage unit  250  may include a drainage pipe  252  disposed at the lower side of the tub  170  for defining a drainage channel and a drainage pump  254  for pumping the wash water flowing in the drainage channel out of the laundry treatment apparatus  100 . The drainage unit  250  may be disposed between the tub  170  and the drawer  120 . A portion of the drainage pipe  252  may be formed as a bellows pipe in order to prevent the drainage pipe  252  from being separated from the tub  170  due to the vibration of the tub  170  or such that the length of the drainage pipe  252  is adjustable when the drawer  120  is withdrawn. 
       FIG. 8  is a perspective view showing the detergent introduction unit of the drawer according to the embodiment of the present invention, and  FIG. 9  is a sectional view of the detergent introduction unit shown in  FIG. 8 . 
     As shown in  FIGS. 8 and 9 , the detergent introduction unit  154  defines a space for receiving an additive, such as detergent or fabric softener. 
     The detergent introduction unit  154  is disposed on the left side and the right side of the top cover at the front of the drawer body. Depending on the circumstances, the detergent introduction unit  154  may be disposed on one side of the top cover at the front of the drawer body. 
     The detergent introduction unit  154  includes a first introduction unit  155  for receiving fabric softener and a second introduction unit  152  for receiving detergent. 
     Hereinafter, the structure of the detergent introduction unit  154  will be described based on the first introduction unit  155 . The first introduction unit  155  and the second introduction unit  152  may be identical in structure to each other except that the first introduction unit  155  and the second introduction unit  152  are disposed in a symmetrical fashion. 
     The first introduction unit  155  includes an introduction bowl  156  for receiving fabric softener and a detergent housing  157  for receiving the introduction bowl  156 . The first introduction unit  155  further includes a water supply connection pipe  153  connected to a water supply channel for supplying water and an introduction pipe  159  for supplying fabric softener to the tub  170  together with the water through the water supply connection pipe  153 . The introduction pipe  159  is connected to the detergent introduction pipe  160 . 
     The introduction bowl  156  is provided with an introduction hole  158 . The fabric softener in the introduction bowl  156  is introduced into the detergent housing  157  through the introduction hole  158 . As a result, the fabric softener is stored in both the introduction bowl  156  and the detergent housing  157 . 
     In addition, the water that is supplied to the first introduction unit  155  through the water supply connection pipe  153  flows to the detergent housing  157  with the fabric softener through the introduction hole  158  and is introduced into the tub  170  through the introduction pipe  159 . A plurality of introduction holes  158  is formed in the introduction bowl  156 . A first introduction hole  158   a  may be formed so as to be adjacent to the introduction pipe  159 , and a second introduction hole  158   b  may be formed so as to be adjacent to the water supply connection pipe  153 . 
     The water supply connection pipe  153  is connected to the water supply channel in the water supply unit  240  in order to supply water to the first introduction unit  155  via the water supply channel. The water that is supplied through the water supply connection pipe  153  is primarily received in the detergent housing  157 , and some of the supplied water is introduced into the introduction bowl  156  through the introduction hole  158 . The water flows from the introduction bowl  156  to the detergent housing  157  through the introduction hole  158 , and is introduced to the tub  170  through the introduction pipe  159 . 
     The introduction pipe  159  is configured to have a structure using a siphon phenomenon, in which, when liquid supplied to the introduction pipe exceeds a predetermined level, the liquid in the introduction pipe is discharged to the outside. Once the liquid flows, all of the liquid received in the introduction pipe is discharged due to the force of the liquid that flows. 
     The fabric softener received in the introduction bowl  156  and the detergent housing  157  is mixed with the water that is introduced through the water supply connection pipe  153 . When the level of the mixture of the water and the fabric softener becomes higher than the free end of the introduction pipe  159 , the mixture is discharged through the introduction pipe  159  due to water pressure, and a siphon phenomenon occurs in the first introduction unit  155 . Due to the siphon phenomenon, the mixture in the first introduction unit  155  flows along the introduction pipe  159  and is introduced into the tub  170 . As a result, the remaining water is removed from the first introduction unit  155 . 
     In the case in which the supply of water through the water supply connection pipe  153  is stopped when a siphon phenomenon occurs in the first introduction unit  155 , all of the mixture in the first introduction unit  155  may move to the tub  170  through the introduction pipe, whereby the remaining water may be removed from the first introduction unit  155 . 
     In the case in which water is continuously supplied through the water supply connection pipe  153  when a siphon phenomenon occurs in the first introduction unit  155 , the additionally supplied water may remain in the first introduction unit  155 . 
     The first laundry treatment apparatus is configured such that water is not continuously supplied to the first introduction unit but the supply of water is stopped for a predetermined amount of time after water is supplied for a specific amount of time. The first laundry treatment apparatus is configured such that the supply of water is stopped for a predetermined amount of time in order to remove the remaining water from the first introduction unit using a siphon phenomenon. 
       FIG. 10  is a reference view illustrating a water supply channel in the drawer according to the embodiment of the present invention. 
     As shown in  FIG. 10 , when water from a water supply hose is supplied to the water supply unit  240  via the water supply valve  244  (F 1 ), the water is introduced into the tub  170  through the water supply pipe  242  (F 2 ). In addition, the water from the water supply hose is supplied to the detergent introduction unit  154  through a water supply channel (not shown) defined in the lower part of the top cover  140  (F 3  and F 4 ). The water supply channel diverges from the water supply pipe  242  and is formed in the left upper end and the right upper end of the drawer and in the lower part of the top cover  140  in order to supply water to the first introduction unit  155  and to the second introduction unit  152 . 
     The supply of water to the water supply pipe  242 , through which water is directly introduced into the tub  170 , and to the second introduction unit  152  is controlled by the water supply valve  244 . 
     In the water supply channel connected to the first introduction unit  155  is mounted a first valve  371  for controlling the supply of water to the first introduction unit  155 . 
     During washing and rinsing, some of the supplied water is supplied to the tub through the water supply pipe  242  (F 2 ), and some of the supplied water is supplied to the second introduction unit  152  through the water supply channel (F 4 ), whereby the water is supplied into the tub together with the detergent in the second introduction unit. 
     Fabric softener is not introduced during washing but is introduced during final rinsing. In the laundry treatment apparatus, therefore, the first valve is controlled to supply water to the first introduction unit  155  (F 3 ) such that the fabric softener is supplied to the tub  170  during final rinsing. 
       FIG. 11  is a block diagram schematically showing the control construction of the first laundry treatment apparatus according to the embodiment of the present invention. 
     As shown in  FIG. 11 , the first laundry treatment apparatus includes a manipulation unit  330 , an output unit  340 , a sensor unit  350 , a driving controller  360 , a water supply unit  240 , a drainage unit  380 , a communication unit  390 , a memory  320 , and a controller  310  for controlling the overall operation thereof. 
     The manipulation unit  330  includes input means, such as at least one button, a switch, and a touchpad, which are provided at the control panel  128 . 
     The manipulation unit  330  allows operation settings, including power on/off, operation mode, kind of laundry, washing course, water level, and temperature, to be input. When the kind of laundry is selected and the power is turned on through the manipulation unit  330 , data regarding the operation settings are input to the controller  310 . In the case in which the first laundry treatment apparatus and the second laundry treatment apparatus are installed so as to be adjacent to each other within a predetermined distance or in the case in which the first laundry treatment apparatus and the second laundry treatment apparatus are disposed one on another, the manipulation unit  330  may include a twin washing key (not shown) for allowing the two laundry treatment apparatus to be operated together. 
     The output unit  340  outputs information about the operation settings and the operational state of the laundry treatment apparatus. 
     The output unit  340  includes a display for displaying a combination of one of more selected from among letters, numerical icons, images, and special characters on a screen, a lamp for indicating the operational state of the laundry treatment apparatus depending on lighting thereof, and a speaker or a buzzer for outputting a predetermined effect sound or warning sound. 
     The display may include a menu screen for operation settings and operation control of the laundry treatment apparatus, and may output an announcement message or a warning message including a combination of one or more selected from among letters, numbers, and images for operation settings and operation control of the laundry treatment apparatus. 
     The output unit  340  may output a warning sound or a warning message when the laundry treatment apparatus is in an abnormal state. 
     The memory  320  stores control data for operation control of the laundry treatment apparatus, data regarding the input operation settings, data regarding operation time calculated based on settings, data regarding a washing course, and data for determining whether errors have occurred. 
     In addition, the memory  320  stores data that is generated during the operation of the laundry treatment apparatus or sensed by the sensor unit  350  and data that is transmitted and received through the communication unit  390 . 
     The memory  320  may be a hardware storage device, such as a ROM, a RAM, an EPROM, a flash drive, and a hard drive. 
     The communication unit  390  transmits and receives data in a wired or wireless fashion. 
     The communication unit  390  may be connected to a network provided in a building or within a predetermined distance, such as a home network, in order to transmit and receive data. In addition, the communication unit  390  may be connected to an external server, such as the Internet, in order to communicate with a terminal having a control function. 
     The communication unit  390  may transmit the operational state of the laundry treatment apparatus to a terminal or to another laundry treatment apparatus, and may receive a control command from the terminal or from an external server. 
     In the case in which the first laundry treatment apparatus and the second laundry treatment apparatus are installed so as to be adjacent to each other within a predetermined distance, the communication unit  390  may transmit and receive data regarding the operation settings or the operational state of the second laundry treatment apparatus to and from the second laundry treatment apparatus such that the laundry treatment apparatuses can be operated together. For example, in the case in which the laundry treatment apparatuses are disposed one on another, the laundry treatment apparatuses may not simultaneously perform operations that generate vibrations based on received data. 
     The communication unit  390  transmits and receives data using short-distance wireless communication, such as ZigBee, Bluetooth, WiFi, or WiBro. 
     A power supply unit (not shown) converts commercial power supplied from the outside into operation power and supplies the converted operation power. The power supply unit interrupts the supply of overcurrent. The power supply unit rectifies and smooths power supplied from the outside in order to supply a predetermined operation power. 
     The sensor unit  350 , which includes a plurality of sensors, measures the voltage or current of the laundry treatment apparatus and senses the rotational speed of a motor, a water level, temperature, and humidity. The measured and sensed values are input to the controller  310 . 
     The sensor unit  350  may include a door sensor (not shown), a temperature sensor (not shown), a current sensor (not shown), and a water level sensor. In addition, the sensor unit  350  may further include a speed sensor for sensing the rotational speed of the motor, a humidity sensor, and a laundry sensor for sensing the state/material of laundry. 
     The temperature sensor senses the temperature in the laundry treatment apparatus and the water temperature. In the case in which a heater is provided, the temperature sensor senses the temperature of the heater. A plurality of temperature sensors may be provided at different positions in order to sense temperature. The water level sensor senses the level of water that is supplied to the tub  170 . The current sensor senses current that is supplied to the motor. The door sensor senses whether the door is open or closed. Before the laundry treatment apparatus is operated based on the settings, the door sensor senses whether the door is open or closed, and transmits a sensing signal to the controller  310 . In addition, the door sensor may sense whether laundry is caught in the door. 
     The driving controller  360  performs control such that current is supplied to the driving unit  220  and then the driving unit is rotated. The driving controller  360  converts power supplied from the outside into power necessary to rotate the driving unit  220  in order to control the operation of the driving unit  220 . 
     The driving controller  360  controls the rotational direction, the rotational angle, and the rotational speed of the driving unit  220  according to a control command of the controller  310 . The driving unit  220  is a motor. The driving controller  360  performs control such that the driving unit  220  is operated differently based on the set washing course and on whether washing, rinsing, or spin-drying is to be performed. The driving controller  360  controls the rotational direction, the rotational angle, and the rotational speed of the driving unit differently such that the wash water in the drum generates a water current having a specific form. 
     The water supply unit  240  controls the opening and closing of the water supply valve  244  and the first valve  371 . Based on washing and rinsing cycles, the water supply unit  240  continuously supplies water or supplies water for a predetermined amount of time and then interrupts the supply of water, which is repeatedly performed such that water is intermittently supplied. At the time of final rinsing during the rinsing cycle, the water supply unit  240  controls the first valve such that water is supplied to the first introduction unit  155 . 
     The drainage unit  380  controls the opening and closing of a drainage valve  381  and the operation of a drainage pump  382  such that the water in the tub  170  is discharged to the outside through a drainage hose. 
     The controller  310  controls a series of washing procedures, including washing, rinsing, spin-drying, and drying. In the following description, the term “washing” refers to all operations of the laundry treatment apparatus, including a washing cycle, a rinsing cycle, a spin-drying cycle, and a drying cycle. 
     The controller  310  stores the operation settings in the memory  320  and signals a water level, temperature, and control pattern based on a washing course corresponding to the data stored in the memory in order to control the operation of the laundry treatment apparatus. 
     The controller  310  performs control such that the operation settings or the operational state of the laundry treatment apparatus is output through the output unit  340 . In addition, the controller  310  performs control such that data is transmitted to the outside through the communication unit  390  and such that data received from the outside through the communication unit  390  is processed. The controller  310  may change the operation settings such that the laundry treatment apparatus is operated together with another laundry treatment apparatus based on data of the another laundry treatment apparatus received through the communication unit  390 . 
     The controller  310  controls the water supply unit  240  and the drainage unit  380  such that water is supplied to the tub  170  and water is drained from the tub  170  depending on the operation settings, and transmits a control command to the driving controller  360  such that the drum is rotated to perform washing according to the operation of the driving unit. In addition, the controller  310  transmits a control command to the heater (not shown) such that the heater heats wash water or such that a drying cycle is performed. 
     In addition, while water is supplied up to a predetermined level of the tub  170 , the controller  310  controls the water supply unit  240  such that water is directly introduced into the tub or is supplied into the tub through the first introduction unit  155  or the second introduction unit  152  through the opening and closing of the valve. 
     The water supply unit  240  controls the opening and closing of the water supply valve  244  and the first valve  371  in response to a control command of the controller  310 . 
     During a rinsing cycle, the controller  310  controls the water supply unit  240  such that some of the water is directly introduced into the tub and such that some of the water is supplied to the tub through the first introduction unit  155 , whereby the fabric softener in the first introduction unit is introduced into the tub together with the water. 
     The water supply unit  240  does not continuously supply water but supplies water for a predetermined amount of time and then stops the supply of water, which is repeatedly performed such that the fabric softener in the first introduction unit is introduced into the tub and such that no water remains in the first introduction unit. 
     The water supply unit  240  may supply water to the second introduction unit  152  in the same manner. Since detergent is received in the second introduction unit, the supply of water to the second introduction unit may be controlled before washing such that no water remains in the second introduction unit. 
       FIG. 12  is a reference view illustrating the principle by which a detergent introduction unit according to an embodiment of the present invention is operated. 
     As shown in  FIG. 12 , the first introduction unit  155  is configured. 
     As described above, the first introduction unit  155  includes the introduction bowl  156  and the detergent housing  157 . The introduction pipe  159 , which is defined by the introduction bowl and the detergent housing, has a siphon structure, as shown in the figure. 
     In the case in which the level of the water in the first introduction unit exceeds a reference water level h 1 , a mixture in the introduction bowl and the detergent housing, i.e. a mixture of water and fabric softener, is discharged to the outside through the introduction pipe  159 . 
     In the case in which water is supplied through the water supply connection pipe  153  while the water (the mixture) in the first introduction unit is discharged to the tub as the result of the level of the water in the first introduction unit exceeding the reference water level, some water remains in the first introduction unit when the supply of water is stopped. Meanwhile, in the case in which the supply of water is stopped when the water (the mixture) starts to be discharged from the first introduction unit, all of the water may be introduced into the tub due to a siphon phenomenon. 
     In the case in which the level of the water in the first introduction unit is equal to or lower than a predetermined water level h 2 , all of the water in the first introduction unit may be discharged due to a siphon phenomenon. In the case in which the level of the water in the first introduction unit is higher than the predetermined water level h 2  and is lower than the reference water level h 1 , some of the water remains in the first introduction unit even when the water is discharged through the introduction pipe. 
     On the assumption that a siphon operation time until siphon operation is performed when water is supplied to the first introduction unit is ts and a time until the level of the water in the first introduction unit reaches a bottom level after the siphon operation is performed, i.e. an introduction time, is te, an additional water supply time ta must be longer than the siphon operation time ts. The siphon operation time is a time until the mixture in the first introduction unit starts to be introduced into the tub after water is supplied to the first introduction unit. 
     The value obtained by subtracting the siphon operation time ts from the additional water supply time ta is a time during which water is additionally supplied after the siphon operation is performed, which is related to the amount of water remaining in the first introduction unit. 
     In the case in which the value obtained by subtracting the siphon operation time ts from the additional water supply time ta is greater than the introduction time te to the bottom level, some water remains in the first introduction unit. In the case in which the value obtained by subtracting the siphon operation time ts from the additional water supply time ta is equal to or less than the introduction time te to the bottom level, no water remains in the first introduction unit. 
     Consequently, the water level h 2  is set based on the level of water that is supplied to the first introduction unit during the introduction time te to the bottom level. The water level h 2  may be variable depending on the capacity, water pressure, reference water level, water supply amount, and water introduction amount of the first introduction unit. 
     The controller  310  controls the water supply unit  240  such that the supply of water to the first introduction unit is stepwise controlled during a rinsing cycle in order to prevent some water from remaining in the first introduction unit. 
     At the time of first supply of water during the rinsing cycle, water is supplied to the first introduction unit based on the water level in the tub, which is set depending on a washing course. For this reason, it is difficult to determine whether some water remains in the first introduction unit. Consequently, the controller  310  performs control such that water is additionally supplied to the first introduction unit stepwise in order to prevent some water from remaining in the first introduction unit. 
     Since it takes time until water is discharged due to a siphon phenomenon (the introduction time to to the bottom level), as described above, the controller  310  performs control such that water is supplied for a specific amount of time and then the supply of water is stopped for a predetermined amount of time in order to introduce the water from the first introduction unit to the tub. In addition, since it is not possible to sense the level of the water remaining in the first introduction unit, the controller  310  performs control such that the additional supply of water is performed in two stages in order to prevent some water from remaining in the first introduction unit irrespective of the level of the remaining water. At the time of additional supply of water, a water supply time and an interruption time may be set based on the predetermined water level described above in consideration of the capacity of the first introduction unit, the water supply flow rate, and the drainage flow rate. 
     After the first supply of water, additional supply of water may be performed twice in consideration both of the case in which the level of the remaining water is higher than a predetermined water level and of the case in which the level of the remaining water is equal to or lower than the predetermined water level. 
       FIGS. 13 and 14  are reference views illustrating the amount of water that remains in the detergent introduction unit through water supply control according to an embodiment of the present invention. 
     As described with reference to  FIG. 12 , whether water remains in the first introduction unit at the time of additional supply of water is determined depending on the level of the remaining water in the first introduction unit. 
     At the time of first supply of water to the first introduction unit, it is not possible to accurately check the amount of remaining water, since the amount of water that is supplied is variable depending on a washing course. After the first supply of water to the first introduction unit, therefore, the additional supply of water may be performed depending on the case in which the level of the remaining water is higher than the predetermined water level and the case in which the level of the remaining water is equal to or lower than the predetermined water level. 
     In the case in which the level of the remaining water in the first introduction unit is a first water level h 3 , which exceeds the predetermined water level, after the first supply of water, as shown in  FIG. 13( a ) , there is remaining water at the time of additional supply of water (second supply of water), as shown in  FIG. 13( b ) . At this time, the level of the remaining water is a second water level h 5 , which is lower than the predetermined water level h 2 . When the additional supply of water (third supply of water) is performed, therefore, all of the water in the first introduction unit is introduced into the tub, whereby there is no remaining water, as shown in  FIG. 13( c ) . 
     Also, in the case in which the level of the remaining water in the first introduction unit is a third water level h 4  after the first supply of water, as shown in  FIG. 14( a ) , the third water level h 4  is lower than the predetermined water level h 2 . When the additional supply of water (second supply of water) is performed, therefore, there is no remaining water, as shown in  FIG. 14( b ) . 
     When the additional supply of water (third supply of water) is performed in the state in which there is no remaining water (h 6 ), as shown in  FIG. 14( b ) , there is no remaining water in the first introduction unit, as shown in  FIG. 14( c ) . 
     At the time of additional supply of water, a water supply time and an interruption time may be set in consideration of a siphon operation time ts until a siphon operation is performed and a time ts until the level of the water in the first introduction unit reaches the bottom level after the siphon operation is performed, as described with reference to  FIG. 12 . Even though the amount of remaining water at the time of first supply of water is not checked, the additional supply of water is performed twice while controlling a water supply time and an interruption time, as described above, whereby no water remains in the first introduction unit. 
       FIG. 15  is a reference view illustrating a water supply method of the first laundry treatment apparatus according to the embodiment of the present invention. 
     As shown in  FIG. 15 , the water supply unit  240  controls the water supply valve  244  and the first valve  371  in response to to a control command from the controller  310 . 
     The water supply valve  244  is a main valve for supplying water from the water supply hose to the laundry treatment apparatus, and the first valve  371  is a valve for controlling the supply of water to the first introduction unit. 
       FIG. 15( a )  shows the opening and closing operation of the water supply valve  244 , and  FIG. 15( b )  shows the opening and closing operation of the first valve  371 . A water supply procedure will be divided into a plurality of periods in order to describe the operation of the water supply valve and the first valve. In the following description, the water supply procedure is a procedure of introducing fabric softener into the tub at the time of final rinsing. 
     In the case in which water is supplied to the first introduction unit, the water supply unit  240  controls the first valve  371  before controlling the water supply valve  244 , for example, at the final rinsing step. When the water supply valve is opened, the operation of the first valve may be limited due to water pressure. That is, the first valve may malfunction due to water pressure. For this reason, the first valve is controlled, and then the water supply valve is controlled. 
     In a first period D 1 , before water is supplied, the water supply unit opens the first valve (t 0 ) and then opens the water supply valve (t 1 ) such that water is introduced into the tub  17  through the water supply pipe  241 . In addition, the water is supplied to the first introduction unit and the second introduction unit through the water supply channel diverging from the water supply pipe. 
     When the water in the tub  170  reaches a predetermined water level, the water supply unit  240  temporarily stops the supply of water. At this time, the water supply valve is closed (t 2 ) in consideration of the length of the water supply channel to the first valve and the amount of water remaining in the water supply channel, and the first valve is closed (t 3 ) after a predetermined amount of time. 
     In the case in which the supply of water is temporarily stopped by input through the manipulation unit in the first period, the water supply unit closes the water supply valve and the first valve. When the temporarily stopped state is released, the first operation (t 0 ) of the first period is performed again. 
     When first supply of water is completed in the first period D 1 , the water supply unit stops the supply of water for a predetermined amount of time and then opens the water supply valve such that water is supplied to the tub  170  in a second period D 2 . The first valve remains closed. Water is directly introduced into the tub through the water supply pipe, and some of the water is introduced into the tub through the second introduction unit. No water is introduced into the first introduction unit. 
     While the supply of water to the first introduction unit is stopped, some of the water in the first introduction unit may be introduced into the tub, and some of the water may remain in the first introduction unit. It takes time until the water is discharged due to the siphon operation. Consequently, the supply of water to the first introduction unit is stopped in order to discharge water from the first introduction unit. 
     In the case in which the supply of water is temporarily stopped by the manipulation in the second period, the water supply unit  240  stops the supply of water. When the temporarily stopped state is released, the first operation (t 3 ) of the second period is performed again. 
     After the supply of water in the second period D 2 , the water supply unit  240  closes the water supply valve  244  in order to stop the supply of water. 
     In a third period D 3 , the water supply unit  240  opens the first valve (t 6 ) after a predetermined amount of time in the state in which the water supply valve  244  and the first valve  371  are closed (t 5 ), and opens the water supply valve after a predetermined amount of time. 
     Water is introduced into the tub through the water supply pipe  242 . In addition, the water is supplied to the first and second introduction units through the water supply channel and is then introduced into the tub. 
     In the third period, the additional supply of water (second supply of water) to the first introduction unit is performed. 
     The water supply unit  240  supplies water to the first introduction unit for a predetermined amount of time. 
     After the predetermined amount of time, the water supply unit  240  closes the water supply valve, and then closes the first valve in order to stop the supply of water (t 8  and t 9 ). 
     In the case in which the operation is temporarily stopped in the third period, the water supply unit closes the water supply valve and the first valve in order to stop the supply of water. When the temporarily stopped state is released, the first operation (t 5 ) of the third period is performed again. 
     In a fourth period D 4 , the water supply valve and the first valve remain closed for a predetermined amount of time, and the supply of water is stopped. 
     In the third period, the additional supply of water is performed in the state in which some of the water supplied at the time of the first supply of water (the first period) remains in the first introduction unit. In the fourth period, the supply of water is stopped, and the water introduced into the first introduction unit is supplied to the tub together with the fabric softener remaining in the first introduction unit through the introduction pipe  159 . 
     Whether water remains in the first introduction unit at the time of the additional supply of water (second supply of water) is determined depending on the level of the remaining water at the time of the first supply of water. 
     In the case in which the level of the remaining water at the time of the first supply of water in the first period is equal to or higher to a predetermined water level, some water may remain in the first introduction unit or all water may be discharged to the tub through the introduction pipe due to a siphon phenomenon in the fourth period as the result of additional supply of water in the third period. 
     In a fifth period D 5 , the water supply unit opens the first valve  371  (t 10 ) and opens the water supply valve (t 11 ) in order to supply water. 
     In the fifth period, the additional supply of water (third supply of water) to the first introduction unit is performed. 
     In the case in which not all of the water introduced in the third period is introduced into the tub but there is remaining water, the water may be completely introduced into the tub through the additional supply of water in the fifth period. 
     In the case in which the operation is temporarily stopped by the manipulation in the fourth period and the fifth period, the water supply unit performs the operation (t 9 ) of the fourth period again when the temporarily stopped state is released. 
     The fourth period and the fifth period may constitute a single period. 
     After water is supplied for a predetermined amount of time, the water supply unit  240  closes the water supply valve  244  (S 12 ) and then closes the first valve (S 13 ) in order to stop the supply of water. After the first valve is closed, all of the water supplied to the first introduction unit in a sixth period is introduced into the tub due to a siphon phenomenon. 
     Since the level of the remaining water after the additional supply of water in the third period is equal to or lower than the predetermined water level, all of the water in the first introduction unit may be introduced into the tub through the additional supply of water in the fifth period. In a sixth period, all of the water in the first introduction unit is introduced into the tub. 
     In the sixth period D 6 , the first valve remains closed, and no additional supply of water is performed. 
     The water supply unit opens the water supply valve (t 14 ) to supply water up to a predetermined level of the tub. 
     In the case in which the operation is temporarily stopped by the manipulation when water is supplied in the first to fifth periods, the supply of water is stopped. When the temporarily stopped state is released, the water supply unit controls the water supply valve and the first valve such that the initial operation of each period is performed again. 
     The reason that the temporarily stopped operation of each period is not performed but the initial operation of each period is performed again is that it is necessary to perform the operation of each period again in order to normally perform the supply of water, since it is not possible to determine whether there is remaining water as the result of stopping the supply of water to the first introduction unit, and thus the operation is controlled and determined based on the water supply time or the interruption time. Even when the operation is performed again after temporary stoppage, the water supply time in the sixth period is changed, since the final water level is set. 
       FIG. 16  is a flowchart showing a control method of the first laundry treatment apparatus according to the embodiment of the present invention. 
     As shown in  FIG. 16 , when operation settings are input through the manipulation unit  330 , water is supplied to the tub based on a washing course, temperature, etc., and washing is performed. 
     The laundry treatment apparatus removes contaminants from laundry through washing, rinsing, and spin-drying. In addition, the laundry treatment apparatus may dry the laundry after spin-drying the laundry. 
     At the time of washing, the water supply valve is controlled to supply water up to a predetermined level of the tub  170 . When the water supply valve is opened, water is introduced into the tub through the water supply pipe. Some of the water is introduced into the tub together with detergent through the second introduction unit. 
     When washing is completed, water is drained, and water is supplied to the tub again in order to perform rinsing. The rinsing is performed several times depending on settings. 
     After the water is drained from the tub (S 310 ), the controller  310  determines whether rinsing to be performed is final rinsing before rinsing is performed (S 320 ). 
     At the final rinsing, the controller  310  transmits a control command to the water supply unit  240  such that water is supplied to the first introduction unit (S 325 ). 
     At the final rinsing, when water is supplied to the tub  170 , the water supply unit  240  opens the first valve and then opens the water supply valve such that some of the water is supplied to the first introduction unit (first supply of water) (S 330 ). 
     Some of the water is introduced into the tub through the water supply pipe, and some of the water is introduced into the tub through the first and second introduction units via the water supply channel. The fabric softener in the first introduction unit is introduced into the tub  170  together with the water supplied to the first introduction unit. 
     Time for the first supply of water is set based on the level of the water in the tub. When the level of the water in the tub reaches a predetermined water level, the water supply unit closes the water supply valve and then closes the first valve in order to stop the supply of water. 
     A predetermined time after the supply of water is stopped, the water supply unit  240  opens the water supply valve in the state in which the first valve remains closed in order to perform the supply of water (second supply of water) (S 340 ). While water is supplied to the tub through the water supply pipe and the second introduction unit in the state in which the supply of water to the first introduction unit is stopped, the water supplied at the time of the first supply of water is discharged to the tub through the introduction pipe  159 . Water may remain in the first introduction unit depending on the water supply interruption time. 
     After water is supplied for a predetermined amount of time, the water supply unit closes the water supply valve in order to stop the supply of water. 
     After a predetermined amount of time, the water supply unit opens the first valve and then opens the water supply valve in order to perform third supply of water. Water is additionally supplied to the first introduction unit (second supply of water for the first introduction unit) (S 350 ). When water is additionally supplied after the first supply of water, the fabric softener remaining in the first introduction unit is introduced into the tub together with the water. 
     When the water supply valve is closed and then the first valve is closed in order to stop the supply of water, the water supply valve and the first valve remain closed for a predetermined amount of time, whereby the supply of water is stopped. 
     While the supply of water is stopped, the water in the first introduction unit is discharged to the tub through the introduction pipe. At this time, whether water remains in the first introduction unit may be determined depending on the level of the water remaining in the first introduction unit at the time of the first supply of water. As described above, when the level of the water remaining in the first introduction unit at the time of the first supply of water is equal to or lower than the predetermined water level h 2 , additionally supplied water is introduced into the tub due to a siphon phenomenon, whereby all of the water may be discharged. When the level of the water remaining in the first introduction unit at the time of the first supply of water is higher than the predetermined water level, some of the water may remain in the first introduction unit. At this time, the level of the remaining water is equal to or lower than the predetermined water level. 
     After the supply of water is stopped for a predetermined amount of time, the water supply unit  240  opens the water supply valve in order to perform fourth supply of water (S 360 ). 
     The water supply unit closes the water supply valve in order to stop the supply of water. 
     After the supply of water is stopped for a predetermined amount of time, the water supply unit  240  opens the first valve and then opens the water supply valve in order to perform fifth supply of water (S 370 ). 
     As the first valve is opened during the fifth supply of water, third supply of water for the first introduction unit (additional supply of water) to the first introduction unit through the water supply channel is performed for a predetermined amount of time. 
     As the result of the third supply of water to the first introduction unit for the predetermined amount of time, all of the water in the first introduction unit is discharged to the tub. 
     The water supply unit closes the water supply valve and then closes the first valve in order to stop the supply of water. 
     After the third supply of water (the second supply of water to the first introduction unit), since the level of the water remaining in the first introduction unit is lower than a predetermined water level. As a result, while the supply of water to the first introduction unit is stopped, all of the water in the first introduction unit, is supplied at the fifth supply of water, is discharged to the tub due to a siphon phenomenon. 
     After a predetermined amount of time, the water supply unit opens the water supply valve in the state in which the first valve remains closed in order to perform sixth supply of water (S 380 ). Water is continuously supplied to the tub until the level of the water in the tub reaches a predetermined water level. 
     When the supply of water is completed, the drum is rotated by the driving unit in order to perform rinsing (S 390 ). 
     After rinsing, the water is drained and spin-drying is performed (S 400 ). 
     In the present invention, therefore, fabric softener is discharged to the tub together with water through the first introduction unit, which has a siphon structure. In addition, the additional supply of water is stepwise performed for a predetermined amount of time in consideration of the capacity of the first introduction unit, the size of the siphon, the water supply flow rate, and the drainage flow rate, whereby it is possible to remove the remaining water from the first introduction unit. 
     As is apparent from the above description, it is possible for a laundry treatment apparatus according to the present invention and a control method thereof to control the supply of water to a detergent introduction unit, whereby it is possible to easily remove remaining water from the detergent introduction unit. 
     In addition, it is possible to easily set a water supply time based on the capacity of the detergent introduction unit, the water supply flow rate, and the drainage flow rate. 
     In addition, it is possible to secure the time necessary for the water from the detergent introduction unit to be introduced into a tub through water supply control such that detergent or fabric softener in the detergent introduction unit is introduced into the tub together with the water in the detergent introduction unit. 
     In addition, it is possible to control the supply of water irrespective of the level of water that is supplied to the tub and the amount of water remaining in the detergent introduction unit in order to remove remaining water from the detergent introduction unit, whereby it is possible to remove remaining water from the detergent introduction unit even in the case in which the amount of water remaining in the detergent introduction unit is not known. 
     In addition, it is possible to prevent wash water, detergent, or fabric softener from remaining in the detergent introduction unit, whereby it is possible to prevent the detergent introduction unit from being contaminated by remaining water or from becoming clogged. In addition, it is possible to keep the detergent introduction unit clean. 
     Although an exemplary embodiment of the present invention has been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the sprit and scope of the principles of the invention.