Patent Publication Number: US-9432531-B2

Title: Input apparatus following task flow and image forming apparatus using the same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation Application of prior application Ser. No. 13/736,126, filed on Jan. 8, 2013 which is Continuation of prior application Ser. No. 12/276,495, filed on Nov. 24, 2008, now U.S. Pat. No. 8,368,642 in the United States Patent and Trademark Office, which claims priority under 35 U.S.C. §119 (a) from Korean Patent Application No. 10-2007-0132415, filed on Dec. 17, 2007, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present general inventive concept relates to an input apparatus and an image forming apparatus using the same. More particularly, the present general inventive concept relates to an input apparatus in which diverse keys and a display panel are arranged to accommodate a task flow, and an image forming apparatus using the same. 
     2. Description of the Related Art 
     As electronic technology has been developing, diverse image forming apparatuses such as printers, scanners, copiers, and facsimile machines have become widespread. Recently, multifunctional apparatuses integrating functions of diverse image forming apparatuses have been widely distributed. The more functions image forming apparatuses have, the more tasks users can perform using the image forming apparatuses. 
     The user can use the image forming apparatus in the following three situations: when the user writes and prints a document using a computer connected to the image forming apparatus; when the user copies or scans a document by manipulating a control panel of the image forming apparatus; and when a facsimile is externally received and printed. 
     In these cases, the user must be able to input diverse selection commands using an operation panel mounted on the image forming apparatus so as to utilize the image forming apparatus conveniently. However, since the image forming apparatus has more diverse functions but is miniaturized, utilizing the image forming apparatus efficiently and conveniently using the conventional operation panel is difficult. 
     Furthermore, the user needs to recognize whether the image forming apparatus is functioning normally and whether the user is manipulating the image forming apparatus normally when the user carries out a desired task using the image forming apparatus. 
     Accordingly, the conventional image forming apparatus provides the user with feedback of user input using movement of a cursor or texts on the LCD area. However, the LCD area and navigation keys are disperse, so the user can be distracted. That is, in order to check the feedback (reaction) of the image forming apparatus, the user has to monitor the display unit while manipulating the diverse keys. 
     In addition, if the structure of the operation panel is complicated to implement increasingly diverse functions, manipulating the operation panel by the user is difficulty. 
     These limitations are not restricted to the image forming apparatus, but are commonly applied to all electronic apparatuses having diverse menus. 
     SUMMARY OF THE INVENTION 
     The present general inventive concept provides an input apparatus in which diverse keys and a display panel are arranged appropriately according to a task flow and to provide respective feedback in response to user input so that the user can input selection commands efficiently, and an image forming apparatus using the same. 
     Additional aspects and utilities of the present general inventive concept will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the general inventive concept. 
     The foregoing and/or other aspects and utilities of the present general inventive concept may be achieved by providing an input apparatus including a command input unit to input a command, a key input unit having at least one key, a navigation key input unit having a navigation key to perform at least one of a rotation and a selection of a direction, and a display panel unit to perform displaying according to a manipulation of the command input unit, the key input unit, and the navigation key, wherein the command input unit, the key input unit, the navigation key input unit, and the display panel unit are arranged in sequence. 
     The display panel unit may include a variable menu button, and a display panel disposed next to the variable menu button to perform displaying, and to display a menu to be located corresponding with the variable menu button. 
     The display panel unit may further include a mode button disposed at one side of the display panel to set an operation mode of an electronic apparatus to which the input apparatus is applied. 
     The navigation key input unit may further include a state display unit including a plurality of luminous elements which are arranged along a circumference of the navigation key to provide a user with feedback in response to a user input by providing one or more display patterns corresponding to the manipulation of at least one of the command input unit, the key input unit, and the navigation key. 
     The state display unit may provide at least one of the display patterns including a display pattern having lighting luminous elements of a number corresponding to a degree of rotating the navigation key, a display pattern having sequentially lighting and flickering of the plurality of luminous elements in one direction, a display pattern having lighting or flickering of the plurality of luminous elements at the same time, a display pattern having repeating lighting and flickering of the plurality of luminous elements at the same time, and a display pattern having changing a color of the luminous elements. 
     The navigation key input unit may further include a pushable area to be formed on a portion of the navigation key such that if a portion of the pushable area is pressed, the state display unit lights a luminous element corresponding to the pressed portion of the pushable area, and if the navigation key is rotated while a portion of the pushable area is being pressed, luminous elements corresponding to a moving distance of the pressed pushable area. 
     The command input unit, the key input unit, the navigation key input unit, and the display panel unit may be arranged in sequence according to a task flow. 
     The state display unit may provide at least one of the display patterns including a display pattern having sequentially lighting and flickering of the plurality of luminous elements, a display pattern having lighting of the plurality of luminous elements at the same time, a display pattern having repeating lighting and flickering of the plurality of luminous elements at the same time, and a display pattern having changing a color of the luminous elements, corresponding to a state of the electronic apparatus to which the input apparatus is applied. 
     The state of the electronic apparatus includes at least one of power on/off, ready state, power save mode, fax transmission/reception, data transmission/reception, mail transmission/reception, printing state, and error occurring. 
     The foregoing and/or other aspects and utilities of the present general inventive concept may also be achieved by providing an image forming apparatus including an operation panel unit including a command input unit to input a command, a key input unit having at least one key, a navigation key input unit having a navigation key to perform at least one of a rotation and a selection of a direction, and a display panel unit, wherein the command input unit, the key input unit, the navigation key input unit, and the display panel unit are arranged in sequence, and a control unit to perform displaying corresponding to a manipulation of at least one of the command input unit, the key input unit, and the navigation key input unit. 
     The display panel unit may include a variable menu button, and a display panel to be formed next to the variable menu button to perform displaying, and to display a menu to be located corresponding with the variable menu button. 
     The display panel unit may further include a mode button to be formed at one side of the display panel to set an operation mode of an electronic apparatus to which the input apparatus is applied. 
     The navigation key input unit may further include a state display unit including a plurality of luminous elements which are arranged along a circumference of the navigation key, and to provide a user with feedback in response to a user input by operating according to a display pattern corresponding to the manipulation of at least one of the command input unit, the key input unit, and the navigation key. 
     The image forming apparatus may further include a storage unit to store information regarding the display patterns, and an engine controller to control an operation of forming images, wherein the control unit detects the information regarding the display pattern corresponding to the manipulation of at least one of the command input unit, the key input unit, and the navigation key, operation state of the engine controller, and state of the image forming apparatus, from the storage unit, and controls the state display unit to perform displaying corresponding to the detected information regarding the display pattern. 
     The information regarding the display pattern includes information regarding lighting luminous elements of a number corresponding to a degree of rotating the navigation key, sequentially lighting and flickering the plurality of luminous elements in one direction, lighting or flickering the plurality of luminous elements at the same time, repeating lighting and flickering the plurality of luminous elements at the same time, and changing a color of the luminous elements. 
     The control unit controls the state display unit to display at least one of the display patterns including a display pattern having sequentially lighting and flickering of the plurality of luminous elements, a display pattern having lighting of the plurality of luminous elements at the same time, a display pattern having repeating lighting and flickering of the plurality of luminous elements at the same time, and a display pattern having changing a color of the luminous elements, corresponding to a state of the image forming apparatus. 
     The state of the image forming apparatus may include at least one of power on/off, ready state, power save mode, fax transmission/reception, data transmission/reception, mail transmission/reception, printing state, and error occurring. 
     The navigation key input unit may further include a pushable area disposed on a portion of the navigation key such that if a portion of the pushable area is pressed, the state display unit lights a luminous element corresponding to the pressed portion of the pushable area, and if the navigation key is rotated while a portion of the pushable area is being pressed, luminous elements corresponding to a moving distance of the pressed pushable area. 
     The command input unit, the key input unit, the navigation key input unit, and the display panel unit may be arranged in sequence according to a task flow. 
     The foregoing and/or other aspects and utilities of the general inventive concept may also be achieved by providing an input apparatus usable with an electronic apparatus, the input apparatus including a display panel unit to perform displaying according to a user input, and a plurality of input units to allow the user to provide input to the electronic device, wherein an arrangement of the display panel unit and the plurality of input units with respect to each other on the input apparatus is in a sequential order corresponding to an order of actions to be performed by the user to perform a predetermined task. 
     The plurality of input units may include a command input unit to input a command, a key input unit having at least one key, and a navigation key input unit having a navigation key to perform at least one of a rotation and a selection of a direction. 
     The display panel unit may be disposed on a first end portion, the command input unit may be disposed on a second end portion opposite to the first end portion, the key input unit may be disposed between the display panel unit and the command input unit, and the navigation key input unit may be disposed between the key input unit and the display panel unit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and/or other aspects and utilities of the present general inventive will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which: 
         FIG. 1  is a block diagram illustrating a configuration of an input apparatus according to an exemplary embodiment of the present general inventive concept; 
         FIG. 2  is a diagram illustrating in detail a configuration of the input apparatus of  FIG. 1 ; 
         FIG. 3  is a diagram illustrating an example of a process of manipulating a navigation key; 
         FIGS. 4A and 4B  are diagrams illustrating an example of a process of navigating menus according to manipulation of the navigation key; 
         FIG. 5A  is a diagram illustrating an example of a configuration of a state display unit; 
         FIGS. 5B to 5D  are diagrams illustrating diverse display patterns; 
         FIG. 6  is a block diagram illustrating a configuration of an image forming apparatus according to an exemplary embodiment of the present general inventive concept; and 
         FIG. 7  is a block diagram illustrating in detail a configuration of the image forming apparatus of  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference will now be made in detail to embodiments of the present general inventive concept, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiments are described below in order to explain the present general inventive concept by referring to the figures. 
       FIG. 1  is a block diagram illustrating a configuration of an input apparatus according to an exemplary embodiment of the present general inventive concept. As illustrated in  FIG. 1 , the input apparatus  100  includes a display panel unit  110 , a navigation key input unit  120 , a key input unit  130 , and a command input unit  140 . 
     The display panel unit  110  displays menus to set diverse functions of an electronic apparatus in which the input apparatus  100  is mounted, results of executing each function, and messages from the input apparatus  100 . 
     The navigation key input unit  120  includes a navigation key to navigate each menu displayed on the display panel unit  110 . The navigation key may be implemented as a wheel, a jog shuttle, or a jog dial to rotate, for example, 360°. The user can navigate the menus on the display panel unit  110  by rotating the navigation key. 
     The key input unit  130  includes at least one key to input diverse selection commands, such as number keys, and text keys. 
     The command input unit  140  includes command buttons to input diverse commands, such as a start command and a finish command. 
     As illustrated in  FIG. 1 , the display panel unit  110  is located leftmost on the input apparatus  100 , and the navigation key input unit  120 , key input unit  130 , and command input unit  140  are disposed in sequence on a right portion of the display panel unit  110 . This location is determined considering a task flow of the user. For example, such a sequential arrangement would correspond to a predetermined task to be performed that would require a user to first, view the display panel  110 ; second, use the navigation key input unit  120 ; third, use the key input unit  130 ; and fourth, use the command input unit  140 . 
     In greater detail, the user looks at the menus displayed on the display panel unit  110 , and selects a desired menu by manipulating the navigation key on the navigation key input unit  120 . The key input unit  130  may also be used to select the menu. If the menu is selected, the user executes the desired task by manipulating the command input unit  140  located rightmost on the input apparatus  100 . That is, in order to process the task, the user can execute the desired task from left to right efficiently without confusion. 
     For example, if an electronic apparatus to which the input apparatus  100  is applied is a facsimile machine or a multifunctional apparatus having a facsimile function, the user identifies a current state of the electronic apparatus on the display panel unit  110 , and selects an option for facsimile transmission and reception using the navigation key. Subsequently, the user inputs a fax number of a destination using number keys on the key input unit  130 , and then inputs an execution command to transmit the fax using the command input unit  140 . 
     For another example, in the case of a scanner or multifunctional apparatus having a scan-to-email function, the user selects desired options using the display panel unit  110  and navigation key input unit  120 , inputs a mail address of a destination using the key input unit  130 , and selects an execution command on the command input unit  140 . Therefore, the user can operate the input apparatus  100  along the one direction to prevent distracting the user. 
       FIG. 2  is a diagram illustrating in detail a configuration of the input apparatus of  FIG. 1 . As illustrated in  FIG. 2 , the display panel unit  110  may include a display panel  111 , variable menu buttons  112 , and mode buttons  114 . 
     The display panel  111  may be implemented as a liquid crystal display (LCD), cathode-ray tube (CRT), plasma display panel (PDP), or organic light emitting diodes (OLED). 
     The variable menu buttons  112  and mode buttons  114  are located along sides of the display panel  111 . The variable menu buttons  112  are buttons which can vary menus to be executed when one of the variable menu buttons  112  is selected according to the settings of the user. That is, the variable menu buttons  112  can be used as multi-purpose buttons. Menus  113  are displayed on one side of the display panel  111  to correspond to the variable menu buttons  112 . The menus  113  remain on the display panel  111  although an image displayed on the display panel  111  changes. The menus  113  corresponding to each variable menu buttons  112  include various types, such as “menu,” “basic setting”, and “job state.” The types of the menus  113  can be changed by the user. 
     The mode buttons  114  are buttons by which the user can change an operation state of the electronic apparatus to which the input apparatus  100  is applied when the electronic apparatus has various operation states, for example, if the electronic apparatus is a multifunctional image forming apparatus including a scanner, facsimile, and printer modes. Accordingly, the mode buttons  114  can be located around the display panel  111  so that the user can notice them with ease. That is, the mode buttons  114  may be located on the right side of the display panel  111  in a row as illustrated in  FIG. 2 , or located on an upper or lower side horizontally. 
     In  FIG. 2 , the variable menu buttons  112  and mode buttons  114  are implemented as hardware buttons, but may also be implemented as touch-screen buttons. 
     The navigation key input unit  120  includes a navigation key  121  and a state display unit  122 . A press button  123  may be formed on the navigation key  121 . The navigation key  121  rotates about the press button  123 . 
     The press button  123  can operate as a confirmation key to set a menu selected by the navigation key  121 . 
     The state display unit  122  is formed along a circumference of the navigation key  121 , so if the user manipulates the navigation key  121 , the key input unit  130 , or the command input unit  140 , the state display unit  122  provides feedback corresponding to the manipulation. 
     The state display unit  122  includes a plurality of luminous elements. Various display patterns can be provided by lighting or flickering each of the luminous elements in sequence, or lighting or flickering the luminous elements at the same time. For example, the state display unit  122  may be implemented as a light emitting diode (LED) module including a plurality of LEDs. Hereinafter, the state display unit  122  implemented as an LED module is described as an example. 
     The state display unit  122  displays the state using a display pattern, such as by lighting LEDs of a number corresponding to a degree of rotating the navigation key  121 , by sequentially lighting and flickering the plurality of LEDs in one direction, by lighting and flickering the plurality of LEDs at the same time, by repeating lighting and flickering the plurality of LEDs at the same time, or by changing color of the LEDs. 
     Moreover, the state display unit  122  may change the display pattern according to the operation state and condition of the electronic apparatus to which the input apparatus  100  is applied. That is, when the electronic apparatus exhibits a particular condition, such as power on/off, ready state, power save mode, fax transmission/reception, data transmission/reception, mail transmission/reception, printing state, and error occurring, the state display unit  122  lights or flickers the LEDs in a different display pattern depending on each of the situations, so that the user can realize the state of the electronic apparatus with ease. 
       FIG. 3  illustrates one example of a display pattern of the state display unit  122 . If the user presses “a” area on the navigation key  121 , an LED  122   a  corresponding to the “a” area is lit. The remaining LEDs stay unlit. In this state, if “a” area of the navigation key  121  is rotated to “b” area, the LED  122   a  corresponding to the “a” area is flickered and the LED  122   a  corresponding to the “b” area is lit. In another example, if “a” area of the navigation key  121  is rotated to “b” area, two LEDs corresponding to the “a” and “b” areas may be all lit. The state display unit  122  may further include an opaque sheet to cover the LEDs, so light of the LEDs can be dispersed and seen dimly. 
       FIG. 4A  illustrates a state of navigating menus on the display panel unit  110  ( FIG. 2 ) according to manipulation of the navigation key  121  ( FIG. 3 ). As illustrated in  FIG. 4A , various types of higher menus, such as “basic”, “edit”, “application”, and “setting”, are displayed on the display panel  111  of the display panel unit  110 , and each higher menu may change according to a mode which is supported by the electronic apparatus to which the input apparatus  100  is applied. 
     If one of the higher menus is selected, lower menus belonging to the higher menu are displayed under the higher menu. At first, “basic” menu and respective lower menus thereof are displayed, and if the navigation key  121  is rotated by one increment clockwise as illustrated in  FIG. 3 , “edit” menu which is at the right side of the “basic” menu is selected, and the lower menus of the “edit” menu, such as “move image”, “delete outline”, “both-sided”, . . . , and “ccc”, are displayed. 
       FIG. 4B  illustrates a process of navigating lower menus on the display panel unit  110  ( FIG. 2 ) according to manipulation of the navigation key  121  ( FIG. 3 ). Referring to  FIGS. 2 and 4B , in the state that the “edit” menu is selected, if the press button  123  is pressed, a cursor is located on the “move image” menu which is the first menu of the lower menus which are subordinate to the “edit” menu, as illustrated in the left drawing of  FIG. 4B . The press button  123  may be located on any place of the navigation key  121  other than a center of the navigation key  121  in plurality of numbers. The cursor may be expressed by illustrating color, shade, or flickering of the lower menu icons differently. 
     In this state, if the navigation key  121  is rotated clockwise again, the cursor moves to the “delete outline” menu as illustrated in the right drawing of  FIG. 4B . If the press button  123  is pressed, the “delete outline” menu is selected and applied to the task. 
       FIGS. 4A and 4B  illustrate the menu navigation operation using only the navigation key  121 . However, menu selection can also be performed using number keys on the key input unit  130  by allocating a number to each higher menu and lower menu. That is, since the key input unit  130  of  FIG. 2  includes a plurality of number keys and other selection keys, the user can personally input a fax number of a destination, email of a destination, or a short text message. 
     Referring to  FIG. 2 , the command input unit  140  which is located rightmost on the input apparatus  100  includes a start command key  141 , and a stop/clear key  142 . If menu selection and function settings are completed using the navigation key  121  and the key input unit  130 , the user can input a command to execute a task using the command input unit  140 . 
     That is, the user firstly identifies selectable menus on the display panel unit  110  which is located leftmost on the input apparatus  100 , navigates the menus using the navigation key input unit  120  and the key input unit  130  which are located right of the display panel unit  110 , and executes the task using the command input unit  140  which is located rightmost on the input apparatus  100 . Therefore, since a focus of the user can move along the one direction on the input apparatus  100 , distracting the user can be prevented. 
       FIGS. 5A to 5D  are diagrams illustrating various display patterns of the state display unit  122  ( FIG. 2 ) of the navigation key input unit  120  ( FIG. 2 ). For convenience of description, the description focuses on the LEDs except for the opaque sheet on the state display unit  122 . 
     Referring to  FIGS. 2 and 5A , the state display unit  122  are implemented as a plurality of LEDs in pairs. That is, the state display unit  122  includes the LEDs of 8 pairs (for example, # 1  and # 16  are in pairs), and two LEDs constituting one pair may have different colors. Display patterns of two or more colors can be provided by combining the LEDs of 8 pairs having different colors (for example, # 1  and # 16 ). For example, if the LEDs of 8 pairs consists of red LEDs (# 1  to # 8 ) and blue LEDs (# 9  to # 16 ), red LEDs and blue LEDs are used separately or are used together to display a display pattern of pink color. 
     The color of the plurality of LEDs (# 1  to # 16 ) can be used to display a state of the electronic apparatus to which the input apparatus  100  is applied. For example, if the input apparatus  100  is applied to an image forming apparatus, the blue LEDs are used when the image forming apparatus is in a normal state. When the image forming apparatus is in error states, such as in a toner empty state, paper jam state, and cover open state, the red LEDs are used. In addition, when the image forming apparatus is in a warning state, such as in a toner low state and paper mismatching state, the blue LEDs and red LEDs are used together to display pink light. 
     In addition, as illustrated in  FIG. 5B , the state display unit  122  ( FIG. 2 ) can sequentially light and flicker the LEDs (1 st →2 nd → . . . 8 th  LED order) when the electronic apparatus to which the input apparatus  100  is applied is performing a job or searching for a menu or a file. 
     In addition, the state display unit  122  can repeatedly light and flicker the LEDs at the same time as illustrated in  FIG. 5C , and the state display unit  122  can sequentially light the LEDs and flicker all lit LEDs at the same time as illustrated in  FIG. 5D . 
     Such various display patterns are set to correspond to an action of the user or the operation state of the electronic apparatus, and can easily provide feedback of results of the action or the state of the electronic apparatus to the user. 
     As illustrated in  FIGS. 1 and 2 , the display panel unit  110 , navigation key input unit  120 , key input unit  130 , and command input unit  140  are located considering a right-handed user, and may also be located in inverse order in order to correspond to left-handed users. Furthermore, the display panel unit  110 , navigation key input unit  120 , key input unit  130 , and command input unit  140  are located horizontally in  FIGS. 1 and 2 , but may also be located vertically. That is, the display panel unit  110  may be located uppermost, and the command input unit  140  may be located lowermost, so the focus of the user flows from an up to down direction from viewing the display panel unit  110  to viewing the command input unit  140 . 
       FIG. 6  is a block diagram illustrating a configuration of the image forming apparatus  300  to which the input apparatus is applied. The image forming apparatus  300  includes an operation panel unit  100  and a control unit  200 . The operation panel unit  100  can be implemented with the input apparatus  100  as illustrated  FIG. 1  or  FIG. 2 , so for convenience of description, the reference numeral of the operation panel unit is shared with the reference numeral “ 100 ” of the input apparatus. 
     The user can select desired menus and input commands using the operation panel unit  100 . 
     If the user manipulates at least one of the command input unit  140 , the key input unit  130 , and the navigation key input unit  120  on the operation panel unit  100 , the control unit  200  change and displays menus on the display panel unit  110 . If a desired menu is finally selected, a task of applying a function of the selected menu is performed. That is, copying, scanning, printing, or fax transmission and reception can be performed. 
       FIG. 7  is a block diagram illustrating in detail the configuration of the image forming apparatus  300  of  FIG. 6 . The image forming apparatus  300  further includes an engine controller  210 , and a storage unit  220  in addition to the operation panel unit  100  and a control unit  200 . 
     The engine controller  210  controls an operation of an engine which substantially forms images, and operates a developing unit, a charge unit, a laser scanning unit (LSU), a photoconductive unit, a transfer unit, and a fusing unit according to bitmap images input by the control unit  200 . This is the case when the image forming apparatus  300  is a laser image forming apparatus, and the present general inventive concept can also be applied when the image forming apparatus  300  is an inkjet laser image forming apparatus. 
     The engine controller  210  notifies an operation state thereof (for example, a state of forming an image, a stand-by state, or an error occurring state) to the control unit  200 . Therefore, the control unit  200  operates the state display unit  122  to illustrate appropriate display patterns according to the operation state of the engine controller  210  and the state of the image forming apparatus  300 . The state of the image forming apparatus  300  includes power on/off, ready state, power save mode, fax transmission/reception, data transmission/reception, mail transmission/reception, printing state, error occurring, and other states. 
     Information regarding display patterns is detected from the storage unit  220 . The storage unit  220  stores information regarding display patterns according to diverse operation states, such as by lighting LEDs of the number corresponding to the degree of rotating the navigation key  121 , by sequentially lighting and flickering the plurality of LEDs in one direction, by lighting and flickering the plurality of LEDs at the same time, by repeating lighting and flickering the plurality of LEDs at the same time, or by changing color of the LEDs. 
     As described above, the control unit  200  provides the user with appropriate feedback according to the user input or the operation state of the image forming apparatus  300 , so the user can recognize the current operation state of the image forming apparatus  300 . 
     As can be appreciated from the above description, an input apparatus which can be applied to diverse electronic apparatuses including an image forming apparatus according to various embodiments of the present general inventive concept includes a display panel, diverse buttons, and a rotatable navigation key which are arranged according to a task flow. Therefore, such a user-friendly input apparatus allows the user to input selection commands more efficiently and conveniently. 
     Although various embodiments of the present general inventive concept have been illustrated and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the appended claims and their equivalents.