Patent Publication Number: US-8973414-B2

Title: Laundry treating apparatus

Description:
This application is a 35 USC §371 national stage entry of International Application No. PCT/KR2007/002477, filed on Jul. 18, 2007, and claims priority to Korean Patent Application No. 10-2006-0067064, filed Jul. 18, 2006; Korean Patent Application No. 10-2006-0067065, filed Jul. 18, 2006; and Korean Patent Application No. 10-2006-0067066, filed Jul. 18, 2006, all of which are hereby incorporated by reference herein in their entireties. 
     TECHNICAL FIELD 
     The present invention relates to a laundry treating apparatus and a method of controlling the same, and more particularly, to a laundry treating apparatus or a drying machine that is capable of removing or preventing wrinkles or rumples on laundry. 
     BACKGROUND ART 
     A laundry treating apparatus may be classified as a washing or drying machine for washing or drying laundry or a laundry refreshing machine for refreshing laundry. Here, refreshing laundry means the removal of moisture from the laundry, the removal of wrinkles or rumples from the laundry, the removal of static electricity from the laundry, or the removal of a smell from the laundry and the addition of perfume. 
     A drying machine is an electric home appliance that dries washed laundry, for example, washed clothes, using high-temperature air. Generally, the drying machine includes a drum for receiving an object to be dried, a drive source for driving the drum, a heating unit for heating air to be introduced into the drum, and a blower unit for suctioning or discharging air into or out of the drum. 
     Based on how to heat air, i.e., the type of the heating unit, the drying machine may be classified as an electric drying machine or a gas drying machine. The electric drying machine heats air using electric resistance heat. The gas drying machine heats air using heat generated by the combustion of gas. 
     In addition, the drying machine may be classified as a condensation type drying machine or a discharge type drying machine. In the condensation type drying machine, air, heat-exchanged with an object to be dried in a drum and changed into a high-humidity phase, is circulated without discharging the air out of the drying machine. Heat exchange is performed between an additional condenser and external air to produce condensed water, which is discharged out of the drying machine. 
     In the discharge type drying machine, air, heat-exchanged with an object to be dried in a drum and changed into a high-humidity phase, is directly discharged out of the drying machine. Based on how to put laundry in the drying machine, the drying machine may be classified as a top loading type drying machine or a front loading type drying machine. In the top loading type drying machine, an object to be dried is put in the drying machine from above. In the front loading type drying machine, an object to be dried is put in the drying machine from the front. 
     However, the conventional laundry treating apparatus with the above-stated construction has the following problems. 
     Generally, laundry, which has been already washed and spin-dried, is put in a drying machine such that the laundry is dried by the drying machine. However, the water-washed laundry is wrinkled according to the principle of water washing, and the wrinkles on the laundry are not completely removed during the drying process performed by the drying machine. Consequently, an additional ironing process is needed to remove wrinkles on a dried object, i.e., laundry which has been already dried by the conventional drying machine. 
     Furthermore, when clothes as well as washed laundry are normally stored and used, the clothes and the washed laundry may be wrinkled, crumpled, or folded (hereinafter, generally referred to as “wrinkled”). Consequently, there is a high necessity for an apparatus that is capable of easily and conveniently removing wrinkles on clothes during the normal use and storage of the clothes. 
     DISCLOSURE OF INVENTION 
     Technical Problem 
     An object of the present invention devised to solve the problem lies on a laundry treating apparatus that is capable of preventing and/or removing wrinkles on laundry and a method of controlling the same. 
     Technical Solution 
     The object of the present invention can be achieved by providing a laundry treating apparatus including a laundry receiving unit for receiving laundry, a steam generator for generating steam to be supplied to the laundry receiving unit, a water supply unit for supplying water to the steam generator, a water softening member for softening water to be supplied to the steam generator, and a control unit for controlling the replacement or regeneration time of the water softening member to be displayed on a display unit. 
     In another aspect of the present invention, provided herein is a laundry treating apparatus including a laundry receiving unit for receiving laundry, a steam generator for generating steam to be supplied to the laundry receiving unit, a water supply unit for supplying water to the steam generator, a water softening member for softening water to be supplied to the steam generator, a water softening detection unit for detecting whether water to be supplied to the steam generator has been softened, and a confirmation window for allowing a user to confirm the detection result of the water softening detection unit from the outside. 
     In another aspect of the present invention, provided herein is a drying machine including a drum for receiving laundry, the drum being selectively rotatable, a hot air heater for heating air to generate high-temperature hot air to be supplied to the drum, a steam generator for generating steam to be supplied to the drum, a water supply source for supplying water to the steam generator, a water softening member for softening water to be supplied to the steam generator, and a control unit for controlling the replacement or regeneration time of the water softening member to be displayed on a display unit. 
     In a further aspect of the present invention, provided herein is a drying machine including a drum for receiving laundry, the drum being selectively rotatable, a hot air heater for heating air to generate high-temperature hot air to be supplied to the drum, a steam generator for generating steam to be supplied to the drum, a water supply source for supplying water to the steam generator, a water softening member for softening water to be supplied to the steam generator, a water softening detection unit for detecting whether water to be supplied to the steam generator has been softened, and a confirmation window for allowing a user to confirm the detection result of the water softening detection unit from the outside. 
     Advantageous Effects 
     According to the present invention with the above-described construction, it is possible to effectively prevent and/or remove wrinkles on laundry. Furthermore, it is possible to replace or regenerate a water softening member at an appropriate point of time, thereby increasing the efficiency of a steam generator. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention, illustrate embodiments of the invention and together with the description serve to explain the principle of the invention. 
       In the drawings: 
         FIG. 1  is an exploded perspective view illustrating a laundry treating apparatus according to an embodiment of the present invention. 
         FIG. 2  is a vertical sectional view of  FIG. 1 . 
         FIG. 3  is a sectional view illustrating a steam generator of  FIG. 1 . 
         FIG. 4  is a view illustrating a steam generator of a laundry treating apparatus according to another embodiment of the present invention. 
         FIG. 5  is an exploded perspective view illustrating an example of a water supply source of  FIG. 4 . 
         FIG. 6  is an exploded perspective view illustrating a water softening member of  FIG. 5 . 
         FIGS. 7A to 7C  are front views illustrating examples of a display unit for displaying a replacement or regeneration time of the water softening member, which is applied to the present invention. 
         FIG. 8  is a view illustrating another example for informing about a replacement or regeneration time of the water softening member, which is applied to the present invention. 
         FIG. 9  is a sectional view schematically illustrating an example of a pump of  FIG. 4 . 
         FIG. 10  is a perspective view illustrating an installation example of components of  FIG. 4 . 
         FIG. 11  is a perspective view illustrating another example of the water supply source of  FIG. 4 . 
         FIG. 12  is a view illustrating a method of controlling the laundry treating apparatus according to an embodiment of the present invention. 
         FIG. 13  is a flow chart illustrating a method of controlling a pump of  FIG. 12 . 
     
    
    
     MODE FOR THE INVENTION 
     Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. 
     Hereinafter, a front loading electrical condensation type drying machine will be described as an embodiment of the present invention in order to describe a laundry treating apparatus, especially a drying machine, according to the present invention and a method of controlling the same. However, the present invention is not limited to the above-specified drying machine, and therefore, it is also possible to apply the present invention to a top loading gas condensation type drying machine. 
     A laundry treating apparatus, especially a drying machine, according to an embodiment of the present invention and a method of controlling the same will be described with reference to  FIGS. 1 and 2 . 
     In a cabinet  10 , forming the external appearance of the drying machine, are mounted a rotary drum  20 , and a motor  70  and a belt  68  for driving the drum  20 . At predetermined positions, in the cabinet  10 , are mounted a heater  90  (hereinafter, referred to as a “hot air heater” for convenience of description) for heating air to generate high-temperature air (hereinafter, referred to as “hot air”), and a hot air supply duct  44  for hot air, generated by the hot air heater  90 , into the drum  20 . In the cabinet  10  are also mounted an exhaust duct  80  for discharging high-humidity air, heat-exchanged with an object to be dried in the drum  20 , out of the drying machine, and a blower unit  60  for suctioning the high-humidity air. In addition, a steam generator  200 , for generating high-temperature steam, is mounted at a predetermined position in the cabinet  10 . 
     In this embodiment, an indirect drive system, in which the drum  20  is rotated using the motor  70  and the belt  68 , is illustrated and described for convenience of description. However, the present invention is not limited to the indirect drive system. For example, the present invention may be applied to a direct drive system in which the motor is directly connected to the rear of the drum  20  such that the drum  20  is directly rotated by the motor. 
     In this embodiment, laundry is received in the drum  20 . Consequently, a drying machine corresponding to this embodiment includes a laundry receiving unit formed in the shape of the drum  20 . According to the present invention, however, the laundry receiving unit is not limited to the drum. In other words, any laundry receiving units will belong to the technical concept of the present invention so long as steam can be supplied into the laundry receiving units, in which laundry is received. 
     Now, the respective components of the drying machine will be described in detail. 
     The cabinet  10  forms the external appearance of the drying machine. The cabinet  10  includes a base  12  forming the bottom thereof, a pair of side covers  14  mounted vertically on the base  12 , a front cover  16  and a rear cover  18  mounted at the front and rear of the side covers  14 , respectively, and a top cover  17  located at the top of the side covers  14 . A control panel  19 , having various manipulation switches, is normally disposed at the top cover  17  or the front cover  16 . To the front cover  16  is mounted a door  164 . The rear cover  18  is provided with a suction unit  182 , thrash which external air is introduced, and an exhaust hole  184 , which is a final channel for discharging air in the drum  20  out of the cabinet  10 . 
     The interior space of the drum  20  serves as a drying chamber in which a drying process is carried out. Inside the drum  20  are preferably mounted lifts  22  for lifting and dropping an object to be dried, such that the object turns over, to increase the drying efficiency. 
     On the other hand, a front supporter  30  and a rear supporter  40  are mounted between the drum  20  and the cabinet  10  (the front cover  16  and the rear cover  18 ). The drum  20  is rotatably mounted between the front supporter  30  and the rear supporter  40 . Between the front supporter  30  and the drum  20  and between the rear supporter  40  and the drum  20  are mounted sealing members (not shown) for preventing the leakage of air, respectively. Specifically, the front supporter  30  and the rear supporter  40  enclose the front and the rear of the drum  20  to define the drying chamber. Also, the front supporter  30  and the rear supporter  40  serve to support the front and rear ends of the drum  20 . 
     In the front supporter  30  is formed an opening, through which the drum  20  communicates with the outside of the drying machine. The opening is selectively opened and closed by the door  164 . Also, a lint duct  50 , which is a channel for discharging air in the drum  20  out of the drying machine, is connected to the front supporter  30 . In the lint duct  50  is mounted a lint filter  52 . One side of the blower unit  60  is connected to the lint duct  50 , and the other side of the blower unit  60  is connected to the exhaust duct  80 . The exhaust duct  80  communicates with the exhaust hole  184 , which is formed in the rear cover  18 . Consequently, when the blower unit  60  is operated, air in the drum  20  is discharged out of the drying machine through the lint duct  50 , the exhaust duct  80 , and the exhaust hole  184 . At this time, foreign matter, such as fuzz, is filtered out by the lint filter  52 . Generally, the blower unit  60  includes a blower  62  and a blower housing  64 . The blower  62  is generally connected to the motor  70 , which drives the drum  20 . 
     In the rear support  40  is formed an opening  42  including a plurality of through-holes. The hot air supply duct  44  is connected to the opening  42 . The hot air supply duct  44 , communicating with the drum  20 , serves as a channel for supplying hot air into the drum  20 . Consequently, the hot air heater  90  is mounted at a predetermined position on the hot air supply duct  44 . 
     On the other hand, the steam generator  200 , for generating steam to be supplied into the drum  20 , is mounted at a predetermined position in the cabinet  10 . The details of the steam generator  200  will be described with reference to  FIG. 3 . 
     The steam generator  200  includes a water tank  210  for storing water, a heater  240  mounted in the water tank  210 , a water level sensor  260  for sensing the water level in the steam generator  200 , and a temperature sensor  270  for sensing the temperature in the steam generator  200 . The water level sensor  260  includes a common electrode  262 , a low water level electrode  264 , and a high water level electrode  266 . The water level sensor  260  senses a high water level or a low water level in the steam generator  200  based on the current conduction between the common electrode  262  and the high water level electrode  266  or the current conduction between the common electrode  262  and the low water level electrode  264 . 
     To one side of the steam generator  200  is connected a water supply hose  220  for supplying water. To the other side of the steam generator  200  is connected a steam hose  230  for discharging steam. To the tip end of the steam hose  230  is preferably mounted a nozzle  250 , which is formed in a predetermined shape. One end of the water supply hose  220  is connected to an external water supply source, such as a facet. The tip end of the steam hose  230  or the nozzle  250 , i.e., the steam discharge port, is located at a predetermined position in the drum  20  for spraying steam into the drum  20 . 
     Between the water supply hose  220  and the external water supply source may be mounted a valve (not shown) for selectively supplying water to the steam generator  200 . The water supply hose  220  and the valve constitute a water supply unit for supplying water to the steam generator. 
     In this embodiment, on the other hand, the steam generator  200  is constructed in a structure in which a predetermined amount of water stored in the water tank  210 , having a predetermined size, is heated by the heater  240  to generate steam (hereinafter, referred to as a “tub heating type steam generator” for convenience for description). However, the present invention is not limited to the above-specified steam generator. Consequently, the present invention may use any steam generator so long as the steam generator is capable of generating steam. For example, the steam generator  200  may be constructed in a structure in which the heater is directly mounted around the water supply hose, through which water passes, to heat water without storing the water in a predetermined space (hereinafter, referred to as a “pipe heating type steam generator” for convenience for description). 
     Now, a drying machine according to another embodiment of the present invention will be described with reference to  FIG. 4 . 
     In this embodiment, a water supply source  300 , for supplying water to the steam generator, is detachably mounted to a steam generator  200 . As in the previous embodiment, the water supply source may be a facet. In this case, however, the installation of the water supply source is very complicated. This is because water is not generally used in the drying machine, and therefore, when the facet is used as the water supply source, it is necessary to install various devices, which are annexed to the faucet. 
     In this embodiment, therefore, the detachable water supply source  300  is used. Specifically, the water supply source  300  is separated from the steam generator  200  so as to fill the water supply source  300  with water. After the water supply source  300  is filled with the water, the water supply source  300  is connected to the water supply channel of the steam generator  200 , i.e., the water supply hose  220 , which is very convenient. 
     Between the water supply source  300  and the steam generator  200  is preferably mounted a pump  400 . The pump is preferably rotatable in forward and reverse directions. Consequently, it is possible to supply water to the steam generator, and, if necessary, it is possible to collect the remaining water from the steam generator  200 . However, it is also possible to supply water to the steam generator  200  using water head difference between the water supply source  300  and the steam generator  200 , not using the pump  400 . 
     However, various components of the drying machine are normally standardized articles and designed in a compact structure, with the result that the structurally available space of the drying machine is absolutely insufficient. For this reason, the water supply using the water head difference is actually impossible if the size of various components of the conventional drying machine is not changed. Consequently, when the small-sized pump  400  is used, it is possible to install the steam generator  200  without the change in size of various components of the conventional drying machine. The use of the pump  400  is very beneficial. Also, the reason to collect the remaining water from the steam generator  200  is that the heater may be damaged due to the remaining water in the steam generator  200 , or decomposed water may be hereafter used, if the steam generator  200  is not used for a long period of time. 
     The water supply unit for supplying water to the steam generator  200  includes the water supply source  300 , which is detachably mounted to a machine body of the drying machine, an intermediate hose  490 , the pump  400 , and the water supply hose  220 . 
     In the previous embodiment, water is supplied into the upper part of the steam generator  200 , and steam is discharged from the upper part of the steam generator  200 . In this embodiment, on the other hand, water is supplied into the lower part of the steam generator  200 , and steam is discharged from the upper part of the steam generator  200 . This structure is advantageous in collecting the remaining water from the steam generator  200 . Also, a safety valve  500  is preferably mounted on a steam channel for discharging steam from the steam generator  200 , i.e., a steam hose  230 . 
     Hereinafter, the respective components of the drying machine will be described in detail. 
     First, the details of the detachable water supply source  300  (hereinafter, referred to as a “cartridge” for convenience of description) will be described with reference to  FIG. 5 . 
     The cartridge  300  including a lower housing  310  for storing water and an upper housing  320  detachably mounted to the lower housing  310 . When the cartridge  300  is constructed in a structure including the lower housing  310  and the upper housing  320 , it is easy to clean scale accumulating in the cartridge  300 . In addition, it is easy to separate filters  330  and  340  and a water softening member  350  from the upper and lower housings and to clean or regenerate the separate filters  330  and  340  and the water softening member  350 . 
     A first filter  330  is preferably mounted to the upper housing  320 . Specifically, the first filter  330  is mounted in a water introduction part of the upper housing  320  for primarily filtering water when the water is supplied to the cartridge  300 . 
     To the lower housing  310  is preferably mounted an opening and closing member  360  for selectively discharging water in the cartridge to the outside. Consequently, when the cartridge is separated from the drying machine, the water in the cartridge is not allowed to be discharged to the outside, and, when the cartridge is mounted in the drying machine, the water in the cartridge is allowed to be discharged to the outside. To the opening and closing member  360  is preferably mounted a second filter  340  for filtering water. More preferably, the second filter  340  is detachably mounted to the opening and closing member  360 . By the provision of the first filter  330  and the second filter  340 , it is possible to doubly filter out impurities, such as micro dust, from the water. 
     In the cartridge  300  is preferably mounted a water softening member  350  for softening water. More preferably, the water softening member  350  is detachably mounted in the cartridge  300 . As shown in  FIG. 6 , the water softening member  350  includes a lower housing  352  having a plurality of through-holes and an upper housing  353  detachably mounted to the lower housing  352 . The upper housing  353  has a plurality of through-holes. Preferably, a space defined between the upper housing  353  and the lower housing  352  is filled with ion-exchange resin (not shown). 
     However, the present invention is not limited to the above-specified water softening member or any specific water softening mechanism. In other words, the use of any water softening member that is capable of softening water belongs to the technical concept of the present invention. 
     The reason to use the water softening member  350  is as follows. When the hardness of water to be supplied to the steam generator  200  is high, lime, such as calcium carbonate (CaCO 3 ), may be separated as calcium hydrogencarbonate (Ca(HCO 3 ) 2 ), dissolved in the water, is heated, and the heater may be corroded by the lime. 
     Especially, water in Europe and the Americas is hard water having a high hardness. For this reason, the above-mentioned phenomenon may be serious. Consequently, it is preferable to previously remove calcium and magnesium ions, using ion-exchange resin, thereby preventing the separation of lime. The efficiency of the ion-exchange resin is lowered as the water softening process is carried out. Consequently, it is possible to regenerate the ion-exchange resin, using a salt solution (NaCl) such that the ion-exchange resin can be reused. For reference, the water softening process using the ion-exchange resin is represented by 2(R—SONa)+Ca2&lt;-&gt;(R—SO)Ca+2Na, and the regenerating process of the ion-exchange resin is represented by (R—SO)Ca+2NaCl&lt;-&gt;2(R—SONa)+CaCl. 
     In this embodiment, on the other hand, the water softening member  350  is mounted in the cartridge  300 . However, the present invention is not limited to the above-specified structure. For example, the water softening member  350  may be mounted on the intermediate hose  490  or on the water supply channel  220 . That is, it is possible to locate the water softening member  350  at any position in the water supply unit. 
     In other words, the water softening member  350  may be mounted in the cartridge  300  or at any position between the cartridge and the steam generator  200 . 
     In this embodiment, on the other hand, the first filter  330 , the second filter  340 , and the water softening member  350  are mounted to the detachable cartridge  300 . However, the present invention is not limited to the above-specified structure. For example, the present invention may be also applied to a case in which an external facet is used as the water supply source  300 . In this case, it is preferable to mount at least one of the first filter  330 , the second filter  340 , and the water softening member  350  on the water supply channel, connected to the steam generator  200 . Even in this case, it is more preferable to detachably mount the first filter  330 , the second filter  340 , and the water softening member  350  to the cartridge  300 . Also, it is preferable that the first filter  330 , the second filter  340 , and the water softening member  350  are included in a single container, and the container is detachably mounted on the water supply channel. 
     As previously described, the efficiency of the water softening member  350 , for softening water to be supplied to the steam generator  200 , may be lowered with the passage of time or with the increase in frequency of use. Consequently, it is necessary to replace or regenerate the water softening member  350  at an appropriate point of time such that the water softening efficiency of the water softening member  350  is maintained. 
     This is because, when the water softening efficiency of the water softening member is lowered, the purpose of using the water softening member is not accomplished, with the result that calcareous scale accumulates in the steam generator, and therefore, the efficiency of the steam generator may be lowered, or the water supply channel  220  or the steam channel  230  may be clogged. Especially, it is preferable to remove scale, accumulating on the outer surface of the heater, from the heater, thereby maintaining the efficiency of the heater. 
     Consequently, the laundry treating apparatus, especially the drying machine, according to the present invention may include a control unit for controlling a display unit for displaying a replacement or regeneration time of the water softening member such that a user can be easily informed of the replacement or regeneration time of the water softening member. 
     Here, the replacement or regeneration time of the water softening member may be decided based on various factors. 
     As an example, the replacement or regeneration time of the water softening member may be decided based on the frequency of supply of water to the steam generator. Specifically, it is possible for the control unit to aunt the frequency of supply of water to the steam generator using the pump based on the frequency of opening and closing of the valve opened and closed to supply water to the steam generator from the external faucet. 
     Generally, the control unit (not shown) is mounted in the control panel  19  shown in  FIG. 1 . The operation of the laundry treating apparatus is controlled by the control unit. On the other hand, the display unit (not shown) is mounted on the front of the control panel for allowing a user to easily see the information displayed on the display unit. 
     As another example, the replacement or regeneration time of the water softening member may be decided based on whether a specific time has elapsed irrespective of whether the water softening member is used or not. Specifically, the control unit counts time until the replacement or regeneration of the water softening member is needed after the replacement or regeneration of the water softening member is completed. Consequently, the control unit decides that the replacement or regeneration of the water softening member is necessary when the specific time has elapsed. 
     As another example, the replacement or regeneration time of the water softening member may be decided based on the frequency of use of the steam generator. This may be carried out by counting the frequency of supply of electric current to the heater in the steam generator. 
     As a further example, the replacement or regeneration time of the water softening member may be decided based on the accumulated amount of water supplied to the steam generator through the water supply unit. Specifically, the replacement or regeneration time of the water softening member may be decided based on how mush water necessary to generate steam is supplied to the steam generator. When water contains a large amount of limestone, for example, it is possible to lower a reference value with respect to the accumulated amount of water. When water contains a small amount of limestone, on the other hand, it is possible to raise a reference value with respect to the accumulated amount of water. 
     The accumulated amount of water may be easily confirmed by the controller accumulatively counting the quantity of flow measured through a flow meter mounted between the water supply unit and the steam generator. 
     On the other hand, the accumulated amount of water may be easily confirmed by a rotational frequency sensor  950  for sensing the rotational frequency of a gear unit of the pump  400 , as shown in  FIG. 9 . Generally, the amount of water pumped by the pump may be decided in proportion to the rotational frequency of the gear unit. Consequently, when the rotational frequency of the gear unit is decided, it is possible to decide the amount of water supplied through the pump  400 . As a result, it is possible to confirm the accumulated amount of water supplied to the steam generator through the pump by accumulatively counting the rotational frequency of the gear unit. That is, it is possible to easily confirm the accumulated amount of water supplied to the steam generator by the control unit accumulatively counting the rotational frequency of the gear unit sensed by the rotational frequency sensor  950 . 
     The rotational frequency sensor  950  may sense the change of magnetic flux according to the rotation of a magnet  960  formed at a predetermined position of the gear unit to easily sense the rotational frequency of the gear unit. For example, the rotational frequency sensor  950  may by a hole sensor. 
     On the other hand, the replacement or regeneration time of the water softening member is decided by the control unit counting time or frequency. Consequently, the counted time or the counted frequency is preferably reset to an initial value after the replacement or regeneration of the water softening member is completed. Here, the initial value may be “0”. The reset may be accomplished by sensing the attachment or detachment of the water softening member under the control of the control unit. Alternatively, an additional reset button (not shown) may be mounted on the control panel  19  such that the reset is accomplished by pressing the reset button. 
     For example, when the frequency of use of the steam generator is “100”, and the replacement or regeneration of the water softening member is needed, the control unit displays that the replacement or regeneration of the water softening member is needed through the display unit. When a user replaces or regenerates the water softening member, the displayed information disappears from the display unit, the counted frequency of use of the steam generator is reset, and the frequency of use of the steam generator is newly counted. 
     The control unit may further include a memory for storing the frequency of use of the steam generator. The memory may be easily realized by using electrical erasable programmable read only memory (EEP-ROM). On the other hand, an additional battery (not shown) may be included for preventing the memory from being reset to the initial value when a power source is interrupted. 
     Hereinafter, examples of the display unit for displaying the replacement or regeneration time of the water softening member will be described in detail with reference to  FIGS. 7A to 7C . 
     Referring to  FIG. 7A , the display unit displays only the replacement or regeneration time of the water softening member. Specifically, when time, frequency, or the accumulated amount of water, counted by the control unit, exceeds a predetermined value, the display unit  900  displays that the replacement or regeneration of the water softening member is needed. This may be easily realized by lighting a light emitting diode (LED). The display unit  900  may be disposed at one side of the control panel  19 . Of curse, the display unit  900  may also generate a predetermined sound to easily inform a user that the replacement or regeneration of the water softening member is needed. 
     Referring to  FIG. 7B , the display unit displays remaining time, remaining frequency, or the remaining amount of water available as well as the replacement or regeneration time of the water softening member. Specifically, the number of LEDs constituting the display unit  910  is increased as time, frequency, or the amount of water supplied is accumulated. When time or frequency, counted by the control unit, exceeds a predetermined value, all the LEDs of the display unit  910  are lit. Of course, all the LEDs of the display unit  910  are initially lit, and all the LEDs of the display unit  910  are blinked when time or frequency, counted by the control unit, exceeds the predetermined value. 
     Consequently, a user can be easily informed that the replacement or regeneration of the water softening member is necessary after how much time or how many frequencies has elapsed as well as the replacement or regeneration time of the water softening member. Also, the user can be easily informed that the replacement or regeneration of the water softening member is necessary after how much water is further supplied. On the other hand, it is possible to construct the display unit  910  such that the user can be aware of time or frequency assigned to the lighting of each LED. 
     In addition to the above-described display pattern, it is possible to display the replacement or regeneration time of the water softening member with a percentage of 100 and to increase the percentage with the accumulation of the time or the frequency. For example, on the assumption that the replacement or regeneration of the water softening member is needed when the frequency of use of the steam generator is 100, 50% of the LEDs may be lit on the display unit  910  when the frequency of use of the steam generator is 50. 
     The display unit shown in  FIG. 7C  is identical to the display unit shown in  FIG. 7B  except that the display unit  920  is formed in the shape of a bar graph. Consequently, the bar graph is raised as time, frequency, or the amount of water supplied is accumulated. When the time, frequency, or the amount of water supplied exceeds a predetermined value, the bar graph is fully raised. Consequently, it is possible for a user to be easily informed of the replacement or regeneration time of the water softening member. 
     On the other hand, the above-described replacement or regeneration time of the water softening member does not directly represent when the replacement or regeneration of the water softening member is needed. In other words, the replacement or regeneration time of the water softening member is indirectly represented through a predetermined time or frequency. Consequently, the time or the frequency may be large or small depending upon the status of water at a site to which the present invention is applied. For example, the replacement or regeneration of the water softening member may be needed even in a short time or small frequency of use in a region where the hardness of water is very high. On the other hand, the replacement or regeneration of the water softening member may be unnecessary even over a long time or large frequency of use in a region where the hardness of water is very low. Of course, the deviation in the replacement or regeneration time of the water softening member may be reduced depending upon how the initial value is set. 
     Consequently, the drying machine according to the present invention may further include a hardness sensor (not shown) for directly sensing the water softening efficiency of the water softening member and displaying the replacement or regeneration time of the water softening member. 
     The hardness sensor measures the content of minerals in wash water. For example, the hardness sensor measures the content of mineral matter, such as magnesium ions (Mg+) and calcium ions (Ca+), in the wash water. Consequently, it is possible to easily confirm whether water is softened into a satisfactory state thrash the water softening member by using the hardness sensor. 
     On the other hand, the hardness sensor measures the magnitude of conductivity changed depending upon the amount of ions contained in the water. Consequently, a conductivity sensor may be used as the hardness sensor. The amount of ions contained in the water is decided based on the conductivity sensed by the conductivity sensor. 
     The hardness sensor is preferably mounted between the water softening member  350  and the steam generator  200 . When the hardness of water sensed by the hardness sensor exceeds a reference value, the control unit preferably displays that the hardness of water is greater than the reference value through the display unit. 
     When the hardness of water sensed by the hardness sensor exceeds the reference value, for example, it is displayed through a hardness display unit  930 , shown in  FIGS. 7A ,  7 B, and  7 C, that the water softening member cannot sufficiently perform the water softening function. 
     Of course, this display may be realized by an LED or a sound under the control of the control unit. 
     Hereinafter, another example for informing about the replacement or regeneration time of the water softening member, which is applied to the present invention, will be described with reference to  FIG. 8 . 
       FIG. 8  is a structural view illustrating a water softening detection unit for detecting whether water to be supplied to the steam generator shown in  FIG. 4  has been softened. 
     Referring to  FIG. 8 , this embodiment includes a water softening detection unit  970  for detecting the degree of softening of water to be supplied to the steam generator and a confirmation window  980  for allowing a user to confirm the detection result of the water softening detection unit  970  from the outside such that the user can be easily informed about the replacement or regeneration time of the water softening member. 
     Specifically, this embodiment includes the water softening detection unit  970  and the confirmation window  980  instead of the display unit and the control unit for controlling the display unit, which are included in the previous embodiment. Consequently, it is possible for a user to confirm the water softening detection unit  970  through the confirmation window  980 , and therefore, the user is easily informed about the replacement or regeneration time of the water softening member. 
     The water softening detection unit  970 , for detecting the degree of softening of water, is located as shown in  FIG. 8 . 
     According to the present invention, as shown in  FIG. 8 , the water softening detection unit  970  may be located at any position on the water supply channel between the water supply unit and the steam generator. Specifically, the water softening detection is possible as long as water passes through the water softening detection unit  970  before the water, having passed through the water softening member  350 , is supplied to the steam generator. 
     Of course, it is not necessarily needed for the water, having passed through the water softening detection unit  970 , to be supplied to the steam generator. For example, the water softening detection unit  970  may be located at the end of a branch pipe (not shown) diverging from the water supply channel  220 . 
     Preferably, however, the water softening detection unit  970  is mounted between the water softening member  350  and the pump  400 . This is because water does not flow before the pump  400  is driven, and therefore, it is possible to detect PH of the water more accurately. 
     The water softening detection unit  970  may be a PH sensor the color of which is changed depending upon the PH degree of water such that a user can easily determine whether the water has been softened. More specifically, the PH sensor may be a PH paper. 
     When water contains a large amount of limestone, the water exhibits basicity. Consequently, the water exhibits neutrality after the water is satisfactorily softened. When it is detected through the PH paper whether the water has been softened, on the other hand, the degree of softening of the water is easily detected according to the change in color of the PH paper. 
     When water exhibits basicity, for example, the color of the PH paper is changed to yellowish green or celadon green. As the basicity of the water is increased, the color of the PH paper is changed to celadon green. When water exhibits acidity, on the other hand, the color of the PH paper is changed to red or yellow. As the acidity of the water is increased, the color of the PH paper is changed to red. Consequently, when the color of the PH paper is changed to yellow, a user determines that the water is satisfactorily softened by the water softening member. Also, when the color of the PH paper is changed to yellowish green or celadon green, the user determines that the water is not satisfactorily softened by the water softening member. 
     Consequently, it is possible for the user to easily confirm the replacement or regeneration time of the water softening member based on the change in color of the PH paper. 
     On the other hand, it is preferable for the user to easily confirm the result detected by the water softening detection unit through the confirmation window. Consequently, the water softening detection unit is preferably located inside the confirmation window  980  such that the user can see the water softening detection unit through the confirmation window  980  from the outside. For this reason, the confirmation window  980  is preferably a visible window. 
     A position, the most easily accessible by a user, may be the control panel  19  of the laundry treating apparatus. Consequently, the confirmation window  980  is preferably located at the front of the control panel  19  shown in  FIG. 1 . 
     The details of the pump  400 , which is applied to the present invention, will be described with reference to  FIG. 9 . 
     The pump  400  serves to selectively supply water to the steam generator  200 . Specifically, the pump  400  is rotated, in a forward or reverse direction, to supply water to the steam generator  200  or collect the remaining water from the steam generator  200 . 
     The pump  400  is preferably a gear-type pump so as to perform the above-described function.  FIG. 9  illustrates a gear-type pump  400  as an example of the pump  400 . The gear-type pump  400  includes a pair of gears  420  disposed in a case  410 . The case  410  is provided with an inlet port  430  and an outlet port  414 . Specifically, water is discharged from the inlet port  430  to the outlet port  414  or from the outlet port  414  to the inlet port  430  depending upon the rotating direction of the gears  420 . 
     Hereinafter, an installation example of components of a steam line, including the steam generator according to the present invention, will be described with reference to  FIG. 10 . 
     At a predetermined position, in the drying machine, is mounted a drawer-type container (hereinafter, referred to as a “drawer”)  700  that can be inserted and withdrawn. Preferably, the cartridge  300  is mounted in the drawer  700 . Specifically, the cartridge  300  is not directly connected to a connection port  480 . The cartridge  300  is mounted in the drawer  700 , and the drawer  700  is inserted and withdrawn such that the cartridge  300  is indirectly coupled to and separated from the connection port  480 . 
     Preferably, the drawer  700  is located at the front of the drying machine, for example, at the control panel  19 . More specifically, a supporter  820  is mounted at the rear of the control panel  19 . The supporter  820  is arranged approximately in parallel with a top frame  830 . To the supporter  820  and the top frame  830  are mounted a drawer guide  710  for guiding and supporting the drawer  700 . Preferably, a top guide  810  is mounted at a portion of the top of the drawer guide  710 . 
     The top and one side (the front of the drying machine) of the drawer guide  710  are open. The drawer  700  is inserted and withdrawn through the side opening of the drawer guide  710 . The connection port  480  is located at the top of the drawer guide  710  at the other side of the drawer guide  710 . 
     As described above, it is preferable to install the drawer  700  at the front of the drying machine in consideration of convenience in use.  FIG. 10  illustrates the control panel  19  installed at the front cover of the drying machine. Consequently, the drawer  700  is inserted into and withdrawn from the control panel  19 . However, the present invention is not limited to the above-specified structure. For example, when the control panel is mounted at the top cover of the drying machine, as shown in  FIG. 1 , the drawer  700  may be directly mounted at the front cover of the drying machine. 
     When the cartridge  300  is mounted in the drawer  700 , on the other hand, it is preferable that at least opposite sides of the cartridge  300  correspond in shape to those of the drawer  700 , and therefore, the cartridge  300  is tightly coupled to the drawer  700 . At the opposite sides of the cartridge  300  are preferably formed concave parts  301  for allowing a user to mount and separate the cartridge  300  in and from the drawer  700 . 
     Hereinafter, a method of supplying water to the cartridge  300  will be described in detail with reference to  FIG. 10 . 
     When a user withdraws the drawer  700 , the cartridge  300  is also withdrawn. In this state, the user separates the cartridge  300  from the drawer  700 . Subsequently, the user supplies water into the separated cartridge  300  through the water supply port, for example, the first filter  330 , such that the cartridge  300  is filled with the water. After that, the user puts the cartridge  300 , which is filled with the water, in the drawer  700 , and then pushes the drawer  700  inward. As a result, the cartridge  300  is automatically coupled to the connection port  480 , and therefore, the water in the cartridge flows toward the pump  400 . 
     After the use of the drying machine is completed, the user may separate the cartridge from the drawer  700  in the reverse sequence. According to the present invention, the cartridge  300  includes the upper housing  320  and the lower housing  310 . Consequently, it is easy and convenient to clean the separated cartridge  300 . 
     As shown in  FIG. 11 , on the other hand, the drawer  700  may be used as a directly detachable water supply source. When the drawer  700  is used as the directly detachable water supply source, however, water may overflow due to carelessness of a user during the supply of water to the drawer  700 . This problem may be solved to some extent by using the cartridge  300  as the detachable water supply source. When the drawer  700  is used as the directly detachable water supply source, it is possible to simplify the structure of the drawer  700 .  FIG. 11  illustrates the water softening member  350  mounted in the drawer  700  for convenience of description. However, the present invention is not limited to this structure. For example, the first filter  300  and the second filter  340  may be also mounted in the drawer  700 . 
     Hereinafter, a method of controlling the drying machine according to the present invention will be described with reference to  FIGS. 12 and 13 . 
     The method of controlling the drying machine according to the present invention includes a drum heating step (SS 3 ) of heating the drum, a steam supply step (SS 5 ) of supplying steam, generated by the steam generator, to the drum, and a hot air supply step (SS 7 ) for supplying hot air to the drum. Preferably, a water supply step (SS 1 ) is carried out before the drum heating step (SS 3 ). Preferably, the control method according to the present invention further includes a cooling step (SS 9 ) of cooling the drum, which is carried out after the hot air supply step (SS 7 ). 
     Preferably, the control method according to the present invention further includes a water collection step of discharging water remaining in the steam generator, i.e., the remaining water in the steam generator, to the outside, which is carried out after the steam supply step (SS 5 ). (The water collection step will be described hereinafter in detail.) 
     Now, the respective control steps will be described in detail. 
     The drum heating step (SS 3 ) is a step of heating the drum to a predetermined temperature such that the removal of wrinkles on laundry can be more effectively performed at the next step, i.e., the steam supply step (SS 5 ). The drum heating step (SS 3 ) is carried out for a predetermined period of time (T_pre T_pump). At this time, the drum is preferably tumbled. The drum may be intermittently tumbled. Tumbling is rotating the drum at a speed of approximately 50 rpm or less. Tumbling is well known in the art to which the present invention pertains, and therefore, a detailed description thereof will not be given. Preferably, the drum beating step (SS 3 ) is initiated at a point of time when the water level in the steam generator reaches a high water level after water is supplied to the steam generator for a predetermined period of time (T_pump). Also, the steam heater is preferably operated at a point of time when the drum heating step (SS 3 ) is initiated. This is because steam is generated a predetermined period of time after the steam heater is operated. Also, the termination of the drum heating step (SS 3 ) preferably coincides with a point of time when the steam is generated. 
     On the other hand, the drum heating may be accomplished by supplying hot air to the drum. 
     The steam supply step (SS 5 ) is a step of supplying steam to the drum such that the removal of wrinkles on laundry is performed. The steam supply step (SS 5 ) is carried out for a predetermined period of time (T_steam). At this time, the drum is preferably tumbled. More preferably, the drum is intermittently tumbled. The period of time (T_steam), for which the steam supply step (SS 5 ) is carried out, is previously set through experiments based on a factor, such as the amount of an object to be dried. At the steam supply step (SS 5 ), the water level in the steam generator is lowered. Consequently, water is preferably supplied to the steam generator when a low water level is detected. In this case, water may be continuously supplied to the steam generator until the high water level is detected. Preferably, however, water is supplied to the steam generator for a predetermined period of time before the water level in the steam generator reaches the high water level for example, approximately 3 seconds, so as to increase the heating efficiency. Also, it is preferable that tumbling at the steam supply step (SS 5 ) is repeated intermittently and periodically, for example, approximately 3 seconds per minute. 
     The hot air supply step (SS 7 ) is a step of supplying hot air, generated by the hot air heater, to the drum such that laundry, which may be slightly wetted by the steam, is dried again. The hot air supply step (SS 7 ) is carried out for a predetermined period of time (T_dry). At this time, the drum is not tumbled. The period of time (T_dry), for which the hot air supply step (SS 7 ) is carried out, is also previously set through experiments based on a factor, such as the amount of an object to be dried. 
     It is preferable to discharge the water remaining in the steam generator to the cartridge after the hot air supply step (SS 7 ) is completed. At this time, the temperature of the remaining water in the steam generator is high. Consequently, the remaining water in the steam generator is not immediately discharged to the cartridge but the discharge of the remaining water in the steam generator is delayed for a predetermined period of time (T_delay). When the temperature in the steam generator is less than a predetermined temperature (Temp_crit), the remaining water in the steam generator is discharged to the cartridge. (The details will be described below.) 
     The cooling step (SS 9 ) is a step of cooling an object to be dried, the temperature of which has been increased at the hot air supply step (SS 7 ). The cooling step (SS 9 ) is carried out for a predetermined period of time (T_cooling). At this time, the drum is not tumbled. The period of time (T_cooling), for which the cooling step (SS 9 ) is carried out, is also previously set through experiments based on a factor, such as the amount of an object to be dried. Although cool air may be supplied to the drum at the cooling step (SS 9 ), the temperature of the object is not relatively high. Consequently, the object may be left as it is for a predetermined period of time, which is simple but preferred. 
     Hereinafter, a method of controlling the pump according to the present invention will be described with reference to  FIGS. 12 and 13 . 
     The pump control method according to the present invention includes a water supply step (S 100  and S 200 ) of supplying water to the steam generator, which generates steam to be supplied to the drum, and a water collection step (S 300 ) of collecting the water remaining in the steam generator. Of curse, the water supply step (S 100  and S 200 ) preferably includes an initial water supply step (S 100 ) and a water level maintenance step (S 200 ) of maintaining the water level in the steam generator. On the other hand, the water collection step (S 300 ) is preferably carried alt by the pump. More preferably, the water is collected to the detachable water supply source, which is connected to the steam generator. 
     Now, the respective steps will be described in detail. 
     As described above, the water supply step (S 100  and S 200 ) preferably includes the initial water supply step (S 100 ) and the water level maintenance step (S 200 ) of maintaining the water level in the steam generator. The pump is rotated in a forward direction to supply water to the steam generator (S 1 ). When the water level in the steam generator reaches a high water level (S 3 ), the pump is stopped, and the steam heater is operated (S 5 ). 
     As the steam heater is operated, water is heated to generate steam. With the discharge of the generated steam, the water in the steam generator is reduced. Consequently, the water level in the steam generator is detected, and, when the water level in the steam generator reaches a low water level, the pump is rotated in the forward direction to supply water to the steam generator (S 9  and S 11 ). At this time, as previously described, the water may be continuously supplied to the steam generator until the high water level is detected. Preferably, however, water is supplied to the steam generator for a predetermined period of time, for example, approximately 3 seconds, so as to increase the heating efficiency. 
     When a predetermined period of steam supply time (T_steam) has elapsed (S 7 ), on the other hand, the steam heater is stopped (S 13 ), and a predetermined period of time (T_delay) is delayed (S 15 ). The reason why the predetermined period of time (T_delay) is delayed is to maximally lower the temperature of the remaining water in the steam generator. Subsequently, when the temperature in the steam generator is lower than a safety temperature (Temp_crit) (S 17 ), the pump is rotated in the reverse direction for a predetermined period of time, for example, approximately 30 seconds, to collect the remaining water from the steam generator (S 25 ). However, when the temperature in the steam generator is higher than the safety temperature (Temp_crit), the remaining water is not directly collected from the steam generator but safety measures are taken. 
     For example, it is determined whether the water level in the steam generator is lower than the high water level (S 19 ). When it is determined that the water level in the steam generator is lower than the high water level, the pump is rotated in the forward direction for a predetermined period of time, for example, approximately 5 seconds, to supply water to the steam generator (S 21 ). When it is determined that the water level in the steam generator is not lower than the high water level, on the other hand, the temperature in the steam generator is compared with the safety temperature (Temp_crit) (S 23 ). When the temperature in the steam generator is lower than the safety temperature (Temp_crit) (S 23 ), the pump is rotated in the reverse direction for a predetermined period of time, for example, approximately 30 seconds, to collect the remaining water from the steam generator (S 25 ). When the temperature in the steam generator is higher than the safety temperature (Temp_crit), on the other hand, the procedure is ended without the rotation of the pump in the reverse direction to collect the remaining water from the steam generator (S 27 ). Of course, the temperature in the steam generator may be compared with the safety temperature after a predetermined period of time is delayed, and, when the above-mentioned requirement is satisfied, the remaining water may be collected from the steam generator. Here, the safety temperature (Temp_crit) means the maximum temperature at which the reliability of the pump is maintained. For example, the safety temperature is approximately 60 degree. 
     The water supply time (T_pump), the steam generation preparing time (T_pre), the steam supply time (T_steam), the drying time (T_dry), the cooling time (T_cooling), the delay time (T_delay), the tumbling time, and the pump operating time, shown in  FIGS. 12 and 13 , are illustrative examples, and the above-specified times may be appropriately changed depending upon the capacity of the drying machine or the amount of an object to be dried. 
     The results of experiments carried out by the inventors of the present application revealed that the laundry treating apparatus according to the present invention had the effect of removing and preventing wrinkles on laundry although there was a difference depending upon the kinds of laundry, for example, the kinds of laundry materials, and the hygroscopic degree of the laundry. An example of an object to be dried may be laundry spin-dried by a washing machine. However, the object is not limited to the laundry. For example, the present invention is particularly useful when wrinkles on clothes worn approximately one day, i.e., the clothes which are already dried and a little wrinkled, are removed by the drying machine according to the present invention. In other words, the drying machine according to the present invention may be used as a kind of wrinkle removing apparatus. 
     It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. 
     INDUSTRIAL APPLICABILITY 
     As apparent from the above description, the laundry treating apparatus, especially the laundry drying apparatus, and the method of controlling the same according to the present invention have the following effects. 
     First, the present invention has the effect of effectively preventing or removing rumples or wrinkles on a dried object. Also, the present invention has the effect of sterilizing the object and removing a smell from the object. 
     Secondly, the present invention has the effect of effectively removing rumples or wrinkles from dried laundry without additional ironing. 
     Thirdly, the present invention has the effect of effectively softening water to be supplied to the steam generator, thereby preventing the reduction in efficiency of the steam generator due to scale. 
     Fourthly, the present invention has the effect of allowing a user to easily infirm the replacement or regeneration time of the water softening member, thereby appropriately accomplishing the replacement or regeneration of the water softening member.