Patent Publication Number: US-8109481-B2

Title: Operation device and image recording device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims priority from Japanese Patent Application No. 2007-274067 filed on Oct. 22, 2007, the entire contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present invention relates to an operation device including an operation panel body rotatably disposed at a main body and a tilt mechanism configured to maintain the operation panel body at a desired rotation angle, and an image recording device including the operation device. 
     BACKGROUND 
     An operation device including a touch panel or an operation panel having operation buttons is generally provided at a printer, a scanner, a telephone, a facsimile machine, etc. This operation device is desirably arranged on an upper surface of the printer in view of operability of the touch panel or the operation button or a size of the printer. 
     The operation panel may be operated from the upper side of the device and also operated from the front side of the device. Therefore, when the operation panel faces above, operability from the front side of the device becomes worse. Similarly, when the operation panel faces the front surface side of the device, operability from the upper surface side of the device becomes worse. Therefore, there has been proposed an operation device in which an operation panel is disposed a device body capable of falling and rising with respect to the device body, and a posture of the operation panel can be changed to direct the operation panel in any direction of the upper surface side of the device or the front surface side of the device. Such an operation device includes a mechanism capable of holding the operation panel in any posture, the so-called tilt mechanism. 
     JP-A-10-63192 describes an angle holding mechanism in a tilt mechanism for holding a display unit at a desired inclination angle. This angle holding mechanism holds the display unit at the desired inclination angle by locking of a rack to a stopper. Also, when a release button of a release portion is pressed and operated, the locking of the rack to the stopper is released, and the display unit can be rotated. 
     JP-A-11-354941 describes a hinge mechanism in the portable electronic device, in which a mechanism holds a portable electronic device at any angle so as not to move in a direction of closing the portable electronic device by engagement between a ratchet and a latching potion. When the portable electronic device is moved to 90°, the latching portion deviates from a locus of the ratchet and the portable electronic device can be moved in the closed direction. 
     SUMMARY 
     According to the mechanisms disclosed in JP-A-10-63192 and JP-A-11-354941, once the display unit is held at a desired inclination angle, the display unit is not rotated even though pressing force by operation is applied to the display unit. In order to fall the display unit, an operation for releasing an engagement mechanism for holding the inclination angle of the display unit is required. Therefore, a user is forced to perform two operations of the release of engagement and the falling of the display unit, which degrades operability. 
     The invention has been made in consideration of the above circumstances, and an object thereof is to provide a tilt mechanism for maintaining an operation panel body rotatably disposed at a main body at desired rotation angles, in which a posture of an operation panel body can be changed by one action but the operation panel body is resistant to falling even by a pressing operation. 
     According to an aspect of the invention, there is provided an operation device comprising: a main body; an operation panel body attached to the main body rotatably around a rotation axis, such that a rotation of the operation panel body allows a posture of the operation panel body to change to take a first posture falling with respect to the main body and a second posture rising with respect to the main body, and a tilt mechanism configured to maintain the operation panel body at predetermined rotation angles, wherein the tilt mechanism comprises: a plurality of substantially V-shaped recessed grooves formed at one of the operation panel body and the main body, the recessed grooves recessed in a radial direction of the rotation axis of the operation panel body and arranged along a circumferential direction of the rotation axis; a substantially V-shaped pawl member provided at the other of the operation panel body and the main body, the pawl member configured to engage with and disengage from the recessed groove at a predetermined position of the circumferential direction of the rotation axis; and an urging member provided at the other of the operation panel body and the main body, the urging member configured to elastically urge the pawl member in a direction that the pawl member engages with the recessed groove, wherein, when the pawl member is urged by the urging member and engages with the recessed groove, the pawl member contacts with the recessed groove at a first position and a second position, the first position at which a contact pressure in the recessed groove increases in case where the operation panel body rotates toward the first posture side, and the second position at which a contact pressure in the recessed groove increases in case where the operation panel body rotates toward the second posture side, and wherein a following relationship is satisfied: 0°&lt;θ 1 &lt;θ 2 &lt;90° where, in cross-section orthogonal to the rotation axis, an angle θ 1  is defined between: a first imaginary line connecting the first position and the rotation axis; and a second imaginary line along an inclined surface of the first position side in the recessed groove, and an angle θ 2  is defined between: a third imaginary line connecting the second position and the rotation axis; and a fourth imaginary line along an inclined surface of the second position side in the recessed groove. 
     According to another aspect of the invention, there is provided an image recording device comprising an operation device, said operation device comprising: a main body; an operation panel body attached to the main body rotatably around a rotation axis, such that a rotation of the operation panel body allows a posture of the operation panel body to change to take a first posture falling with respect to the main body and a second posture rising with respect to the main body, and a tilt mechanism configured to maintain the operation panel body at predetermined rotation angles, wherein the tilt mechanism comprises: a plurality of substantially V-shaped recessed grooves formed at one of the operation panel body and the main body, the recessed grooves recessed in a radial direction of the rotation axis of the operation panel body and arranged along a circumferential direction of the rotation axis; a substantially-shaped pawl member provided at the other of the operation panel body and the main body, the pawl member configured to engage with and disengage from the recessed groove at a predetermined position of the circumferential direction of the rotation axis; and an urging member provided at the other of the operation panel body and the main body, the urging member configured to elastically urge the pawl member in a direction that the pawl member engages with the recessed groove, wherein, when the pawl member is urged by the urging member and engages with the recessed groove, the pawl member contacts with the recessed groove at a first position and a second position, the first position at which a contact pressure in the recessed groove increases in case where the operation panel body rotates toward the first posture side, and the second position at which a contact pressure in the recessed groove increases in case where the operation panel body rotates toward the second posture side, and wherein a following relationship is satisfied: 0°&lt;θ 1 &lt;θ 2 &lt;90° where, in cross-section orthogonal to the rotation axis, an angle θ 1  is defined between: a first imaginary line connecting the first position and the rotation axis; and a second imaginary line along an inclined surface of the first position side in the recessed groove, and an angle θ 2  is defined between: a third imaginary line connecting the second position and the rotation axis; and a fourth imaginary line along an inclined surface of the second position side in the recessed groove. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing an appearance configuration of a multi function device according to an embodiment of the invention; 
         FIG. 2  is a perspective view showing an appearance configuration of the multi function device in a state of setting a touch panel body in a second posture; 
         FIG. 3  is a perspective view showing a structure of coupling between the touch panel body and a body; 
         FIG. 4  is a cross-sectional view taken along a line IV-IV in  FIG. 3 ; 
         FIG. 5  is a cross-sectional view showing taken along the line IV-IV in the second posture; 
         FIG. 6  is a plan view showing a support structure of a leaf spring; 
         FIG. 7  is a partially enlarged view showing the portion of engagement between a pawl portion and a recessed groove in  FIG. 5 ; and 
         FIGS. 8A and 8B  are partially enlarged views showing the portion of engagement between the pawl portion and the recessed groove in cross-section taken along the line IV-IV. 
     
    
    
     DESCRIPTION 
     An embodiment of the invention will hereinafter be described properly with reference to the drawings. In addition, the present embodiment is only one example of the invention and needless to say, the embodiment can properly be changed without departing from the scope of the invention. 
     [Description of Drawings] 
       FIG. 1  is a perspective view showing an appearance configuration of a multi function device  10  according to an embodiment of the invention.  FIG. 2  is a perspective view showing an appearance configuration of the multi function device  10  in a state of setting a touch panel body  15  in a second posture.  FIG. 3  is a perspective view showing a structure of coupling between the touch panel body  15  and a main body  20 .  FIG. 4  is a cross-sectional view taken along the line IV-IV in  FIG. 3 .  FIG. 5  is a cross-sectional view taken along the line IV-IV in the second posture.  FIG. 6  is a plan view showing a support structure of a leaf spring  33 .  FIG. 7  is a partially enlarged view showing the portion of engagement between a pawl part  38  and a recessed groove  29  in  FIG. 5 .  FIGS. 8A and 8B  are partially enlarged views showing the portion of engagement between the pawl part  38  and the recessed groove  29  in cross-section taken along the line IV-IV. In addition, the cross-section taken along the line IV-IV corresponds to cross-section orthogonal to a rotation axis and is a plane orthogonal to the rotation axis  25 . 
     [Multi Function Device  10 ] 
     As shown in  FIG. 1 , the multi function device  10  includes a printer unit  11  in a lower portion and a scanner unit  12  in an upper portion, and has a print function, a scan function, a copy function and a facsimile function. The multi function device  10  serves as an example of an image recording device. Also, the printer unit  11  in the multi function device  10  may serve as an example of an image recording device. Therefore, the image recording device may be implemented as, for example, a printer having only a print function. 
     The multi function device  10  is connectable to external information devices such as a computer or a digital camera, and records an image or a document on a record sheet based on print data sent from the external information device. Also, various storage media such as a memory card can be mounted to the multi function device  10 . Data such as image data stored on the storage media are read out, and the image can be recorded on the record sheet. 
     An operation unit  13  is disposed on an upper surface of the front surface side of the multi function device  10 . The operation unit  13  is provided at a main body  20  and includes various operation keys  14  and a touch panel body  15 . The operation keys  14  are disposed on a surface of the main body  20  and protrude substantially upward. Therefore, a user can operate the various operation keys  14  from the upper portion of the operation unit  13 . The touch panel body  15  falls to flush with an upper surface of the main body  20  in a first posture, and an operation area  16  of the touch panel body  15  faces substantially upward in the first posture. The user can input a desired command using the operation unit  13 . The multi function device  10  receives a predetermined input and performs a predetermined action. The multi function device  10  is connectable to a computer and operates by a command sent from the computer through a printer driver or a scanner driver, in addition to the command input from the operation unit  13 . This operation unit  13  serves as an example of an operation device, and the touch panel body  15  serves as an example of operation panel body. The operation panel body is a structural body having an operation area in which a predetermined operation is performed by an operation button, a touch panel, etc. 
     In the embodiment, the operation device is implemented as the operation unit  13  of the multi function device  10 , but the operation device is not limited to the multi function device  10 , and can be implemented in a printer, a scanner, a copy machine, a telephone, a facsimile machine, a computer, etc. 
     An opening  17  is formed in the front surface side of the multi function device  10 . A paper feed tray and a paper discharge tray (not shown) are disposed inside the device through the opening  17  to accommodate a record sheet on which an image is recordable by the printer unit  11 . A various techniques such as an ink-jet method, a laser method or a thermal method can be adopted as recording on the record sheet by the printer unit  11 . In addition,  FIGS. 1 and 2  show the multi function device  10  in a state of removing the paper feed tray and the paper discharge tray. The scanner unit  12  includes an auto document feeder (hereinafter called an “ADF”)  18  in an FBS (Flatbed Scanner). In the FBS, an image scanner such as a CIS (Contact Image Sensor) is configured to move with respect to a platen on which a document is placed. In addition, a known configuration can arbitrarily be adopted as an internal configuration of the scanner unit  12  and the printer unit  11 , so that detailed description is herein omitted. 
     [Operation Unit  13 ] 
     The operation unit  13  of the multi function device  10  will hereinafter be described in detail. As shown in  FIG. 1 , the operation unit  13  is provided at a part of the upper surface in the front surface side of the multi function device  10 . The operation unit  13  has a laterally long shape with substantially the same width as a width of the multi function device  10 . The main body  20  of the operation unit  13  is formed integrally with a casing of the multi function device  10 , and various operation keys  14  and the touch panel body  15  are disposed on an upper surface of the main body  20 . 
     The touch panel body  15  has a laterally long rectangle in plan view, and its longitudinal dimension is smaller than a depth dimension of the operation unit  13 . As shown in  FIG. 1 , the touch panel body  15  falls with respect to the main body  20  such that a surface including the operation area  16  is flush with the upper surface of the main body  20 . A posture of this touch panel body  15  is called a first posture in the present specification. On the other hand, as shown in  FIG. 2 , the touch panel body  15  is rotatable so as to rise with respect to the main body  20 . This posture of the touch panel body  15  shown in  FIG. 2  is called a second posture in the present specification. The touch panel body  15  is rotated between the first posture and the second posture by a tilt mechanism and can also be maintained in any posture where a leaf spring  33  engages with a latch member  27  (see  FIG. 5 ). Therefore, a user of the multi function device  10  can change a posture of the touch panel body  15  in any posture with the best visibility or operability of the touch panel body  15 . 
     As shown in  FIG. 4 , the touch panel body  15  includes an upper cover  21  and a lower cover  22  defining a cabinet of the touch panel body  15 , a touch panel module  23  (hereinafter also called a “TP module  23 ”), and a transparent cover  24  for covering an opening of the center of the upper cover  21 . Apart in which the TP module  23  is exposed from the upper cover  21  through the transparent cover  24  serves as to the operation area  16 . 
     The lower cover  22  has substantially a dish shape and a rectangular shape in plan view, and the lower cover  22  defines side surfaces and a back surface of the touch panel body  15 . Although not shown in each of the drawings in detail, bearings are formed at both sides of the device front surface side of the lower cover  22 , and a pair of shafts substantially horizontally disposed at the side of the main body  20  is respectively fitted to the bearing. A rotation axis of the touch panel body  15  formed by the shafts and the bearings is shown as a rotation axis  25  in  FIG. 3 . The touch panel body  15  is supported by the main body  20  and rotatable around this rotation axis  25 . Also, although not shown in each of the drawings, a through hole is formed in the lower cover  22 , and a flat cable  26  for electrically connecting the TP module  23  to a control substrate of the multi function device  10  is led out of the touch panel body  15  through this through hole. 
     The upper cover  21  has a rectangle substantially similar to plan view of the lower cover  22  in plan view, and defines side surfaces and a front surface of the touch panel body  15 . A combination of the upper cover  21  and the lower cover  22  defines a cabinet with substantially a rectangular parallelepiped having internal space capable of accommodating the TP module  23 . An opening corresponding to a screen of the TP module  23  is formed in a surface of the upper cover  21 . The screen of the TP module  23  accommodated in the internal space of the cabinet formed by the upper cover  21  and the lower cover  22  is exposed from this opening. 
     The transparent cover  24  is a sheet with a rectangle shape larger than the opening of the upper cover  21  in plan view. The transparent cover  24  is made of a flexible material having translucency. A user can visually identify display of the TP module  23  through the transparent cover  24  and can apply pressing force in a predetermined place of the TP module  23 . This TP module  23  is configured to, when the predetermined place is pressed from outside, e.g., by a finger, detect a physical change amount in the predetermined place and convert the pressing force into a predetermined input signal. Various methods for detecting its physical change amount, such as a resistance film method, an optical method, a capacitance method, an ultrasonic method, an electromagnetic induction method, is applicable to the TP module  23 . Since a known structure may be applied to the TP module  23 , detailed description is herein omitted. 
     A protective cover  39  is disposed in the lower cover  22 . The protective cover  39  has a flat plate shape with substantially the same width as that of the lower cover  22 . One end side of the protective cover  39  is rotatably attached to the lower cover  22  and the other end side is slidably attached to the main body  20 . The protective cover  39  rises and falls with the rotation of the touch panel body  15  and covers a tilt mechanism and the flat cable  26 . 
     [Tilt Mechanism] 
     A tilt mechanism capable of maintaining the touch panel body  15  at a desired rotation angles will hereinafter be described in detail. This tilt mechanism includes the latch member  27  and the leaf spring  33 . In  FIGS. 4 ,  5  and  7 , a position corresponding to the rotation axis  25  is shows as a point “C.” 
     As shown in  FIGS. 4 and 5 , the latch member  27  is disposed in the lower cover  22 . The latch member  27  is fixed to the lower cover  22  on the device front surface side and on the back surface side of the touch panel body  15 , that is, opposite to the operation area  16 . Therefore, the latch member  27  rotates together with the touch panel body  15 . The latch member  27  includes a base  28  with a circular arc shape around the rotation axis  25  of the touch panel body  15 , and plural recessed grooves  29  formed in an outer circumferential surface of the base  28  and recessed in a radial direction of the rotation axis  25 . The recessed grooves  29  have substantially V shapes and are formed in the base  28  such that the recessed grooves  29  are continuously juxtaposed radially along a circumferential direction of the rotation axis  25 . In the embodiment, five recessed grooves  29  are formed in the base  28 , but the number of recessed grooves  29  can properly be selected according to the number of stepwise postures of the touch panel body  15 . 
     The recessed grooves  29  are not formed in all the outer circumferential surface of the base  28 , and a circumferential surface  30  is disposed on the device back side of the outer circumferential surface of the base  28 . This circumferential surface  30  is inclined in a direction proximate to the rotation axis  25  from the boundary with the adjacent recessed groove  29  toward the device back side. As described below, a pawl portion  38  of the leaf spring  33  abuts on the circumferential surface  30  in a first posture in which the touch panel body  15  is accommodated in a recessed portion  31 . 
     As shown in  FIG. 8A , two inclined surfaces  40 ,  41  having substantially a V shape of each recessed groove  29  are asymmetrical with respect to an imaginary line  42  in cross-sectional view taken along the line IV-IV. In addition, five recessed grooves  29  have the same shape except that arrangement with respect to the rotation axis  25  differs, so that one recessed groove  29  will herein be described in detail. The imaginary line  42  is a straight line connecting the rotation axis  25  (see  FIG. 3 ) and a vertex  43  of the substantially V-shaped recessed groove  29 . When an imaginary line  44  along the inclined surface  40  and an imaginary line  45  along the inclined surface  41  are herein drawn, a relation of A 1 &lt;A 2  is satisfied where the angle A 1  is defined between the imaginary line  42  and the imaginary line  44 , and the angle A 2  is defined between the imaginary line  42  and the imaginary line  45 . Then, A 1  is not equal to A 2 , so that the two inclined surfaces  40 ,  41  are asymmetrical with respect to the imaginary line  42 . 
     As shown in  FIGS. 4 and 5 , the recessed portion  31  configured to accommodate the touch panel body  15  of the first posture is formed in the main body  20 . The recessed portion  31  is space caved from an upper surface of the main body  20  and is formed in a shape mainly along the back surface side of the touch panel body  15 . Also, a region  32  corresponding to the latch member  27  in the recessed portion  31  is caved more deeply. A surface including the operation area  16  in the touch panel body  15  is substantially flush with the upper surface of the main body  20  in a state where the touch panel body  15  of the first posture is fully accommodated in this recessed portion  31 , and a rear surface of the touch panel body  15  contacts with the recessed portion  31 . 
     As shown in  FIG. 6 , the leaf spring  33  is disposed in the region  32  of the recessed portion  31 . A pair of pins  34 ,  35  protruding upward is disposed in the region  32 . The pair of pins  34 ,  35  is separated in a depth direction of the device (a direction vertical to a sheet face of  FIG. 6 ), and a separation distance between the pins  34 ,  35  is set in correspondence with a dimension of a longitudinal direction of the leaf spring  33 . The leaf spring  33  is locked in the pins  34 ,  35 , and the leaf spring  33  is fixed in the region  32  such that its longitudinal direction corresponds to the depth direction of the device. A notch  36  and a hole  37  are respectively formed at both end portions of the longitudinal direction of the leaf spring  33 . The leaf spring  33  is fixed at a predetermined position of the region  32  by engaging the pin  34  with the notch  36  and inserting the pin  35  into the hole  37 . This leaf spring  33  is fixed to extend in a two-dimensional direction (substantially a vertical direction and substantially a horizontal direction in  FIG. 6 ) along a bottom surface of the region  32 . The leaf spring  33  in this fixed state can be elastically deformed in a direction of contact and separation between the latch member  27  and the pawl portion  38  (a direction substantially perpendicular to the paper face of  FIG. 6 ). The fixed position of the leaf spring  33  is set by a relation with each of the recessed grooves  29  of the latch member  27 . 
     The center of the longitudinal direction of the leaf spring  33  is bent in substantially a V shape upward and the pawl portion  38  is formed. As described above, the leaf spring  33  fixed in the region  32  urges the pawl portion  38  into pressure contact with the latch member  27  at a predetermined position of the circumferential direction of the rotation axis  25 . When the latch member  27  rotates together with the touch panel body  15 , the pawl portion  38  can engage with and disengage from the recessed groove  29  of the latch member  27 . The leaf spring  33  elastically urges the pawl portion  38  toward the side of the latch member  27  while the pawl portion  38  contacts with the latch member  27 . The pawl portion  38  serves as an example of a pawl member, and the leaf spring  33  serves as an example of an urging member. In addition, in the embodiment, the pawl member and the urging member are integrally formed by one leaf spring  33 , but it is not always necessary to integrally form these members and, for example, a pawl member may be formed as a separate component urged toward the latch member  27  by a leaf spring. 
     As shown in  FIG. 8B , two inclined surfaces  50 ,  51  having substantially a V shape of the pawl portion  38  are asymmetrical with respect to an imaginary line  52  in cross-section taken along the line IV-IV. The imaginary line  52  is a straight line connecting the rotation axis  25  (see  FIG. 3 ) and a vertex  53  of the substantially V-shaped pawl portion  38 . When an imaginary line  54  along the inclined surface  50  and an imaginary line  55  along the inclined surface  51  are herein drawn, a relation of B 1 &lt;B 2  is satisfied, where the angle B 1  is defined between the imaginary line  52  and the imaginary line  54 , and the angle B 2  is defined between the imaginary line  52  and the imaginary line  55 . Then, B 1  is not equal to B 2 , so that the two inclined surfaces  50 ,  51  are asymmetrical with respect to the imaginary line  52 . 
     As shown in  FIG. 7 , the pawl portion  38  is elastically urged by the leaf spring  33  and contacts and engages at a first position  61  and a second position  62  of the recessed groove  29 . Each of the recessed grooves  29  has the same shape except that arrangement with respect to the rotation axis  25  differs, so that an engagement state of the pawl portion  38  will be described using one recessed groove  29  as an example. 
     The first position  61  is a position in which a contact pressure increases when the touch panel body rotates toward the first posture side. The change in the posture of the touch panel body  15  toward the first posture side corresponds to the rotation of the touch panel body in a clockwise direction in the cross-section taken along the line IV-IV shown in  FIGS. 4 ,  5 ,  7  and  8 . In that case, the pawl portion  38  is pressed by the inclined surface  40  (see  FIG. 8A ) of the recessed groove  29  having the first position  61  toward a direction to be separated from the recessed groove  29 . Since the pawl portion  38  is elastically urged by the leaf spring  33  in a direction of engaging with the recessed groove  29 , it is necessary to move the pawl portion  38  against elastic urging of the leaf spring  33  in order to separate the pawl portion  38  from the recessed groove  29 . In that case, a pressure of contact between the pawl portion  38  and the recessed groove  29  in the first position  61  increases. 
     The second position  62  is a position in which a contact pressure increases when the touch panel body  15  rotates toward the second posture side. The change in the posture of the touch panel body  15  toward the second posture side corresponds to the rotation of the touch panel body  15  in a counterclockwise direction in the cross-section taken along the line IV-IV. In that case, the pawl portion  38  is pressed by the inclined surface  41  (see  FIG. 8A ) of the recessed groove  29  having the second position  62  toward a direction to be separated from the recessed groove  29 . Since the pawl portion  38  is elastically urged in a direction of engaging with the recessed groove  29  by the leaf spring  33 , it is necessary to move the pawl portion  38  against elastic urging of the leaf spring  33  in order to separate the pawl portion  38  from the recessed groove  29 . In that case, a pressure of contact between the pawl portion  38  and the recessed groove  29  in the second position  62  increases. 
     As described above, the recessed grooves  29  and the pawl portion  38  have the substantially V shape. The V shape is a recessed shape defined by intersecting two inclined surfaces at a predetermined angle and is approximated to the V shape when viewed from the cross-section or the side. However, the two inclined surfaces may be a plane surface or a curved surface or these combinations. Also, the so-called R processing or rounding processing may be performed in the bottom portion or vertex at which two inclined surfaces intersect. 
     Here, in section view taken along the line IV-IV, an angle θ 1  is defined as an angle between: an imaginary line  63  connecting the rotation axis  25  (see  FIG. 3 ) and the first position  61  in a state of engaging the pawl portion  38  with the recessed groove  29 ; and the imaginary line  44  along the inclined surface  40  of the side of the first position  61  in the recessed groove  29 . Also, an angle θ 2  is defined as an angle between: an imaginary line  64  connecting the rotation axis  25  and the second position  62 ; and the imaginary line  45  along the inclined surface  41  of the side of the second position  62  in the recessed groove  29 . The angles θ 1  and θ 2  have a relation of 0°&lt;θ 1 &lt;θ 2 &lt;90°. The imaginary line  63  serves as an example of a first imaginary line, the imaginary line  44  serves as an example of a second imaginary line, the imaginary line  64  serves as an example of a third imaginary line, and the imaginary line  45  serves as an example of a fourth imaginary line. 
     [Rotation Action of Touch Panel Body  15 ] 
     As shown in  FIG. 4 , when the touch panel body  15  is in the first posture, the pawl portion  38  of the leaf spring  33  does not engage with all the five recessed grooves  29  and pressure contacts with the circumferential surface  30  of the base  28 . In order to rotate the touch panel body  15  of the first posture in a direction toward the second posture, it is necessary to elastically deform the leaf spring  33  and move the pawl portion  38  toward the radial outside of the rotation axis  25  along the circumferential surface  30 . Also, because gravity acts on the touch panel body  15  in a direction of rotating the touch panel body  15  in the first posture, it is necessary to apply external force (rotational force) against the gravity to the touch panel body  15  in order to rotate the touch panel body  15  of the first posture in a direction toward the second posture. In other words, the touch panel body  15  does not rotate from the first posture without the external force applied to the touch panel body  15  against the gravity and such a leaf spring  33 . The touch panel body  15  can adopt any rotation posture with a rotatable range of the touch panel body  15  at which the pawl portion  38  of the leaf spring  33  pressure contacts with the circumferential surface  30  of the base  28 . Therefore, in the vicinity of the first posture, the touch panel body  15  maintains the first posture by the gravity and the leaf spring  33  described above, and also a surface of the touch panel body  15  including the operation area  16  flush with as an upper surface of the upper cover  21  of the main body  20 . 
     When the touch panel body  15  of the first posture is rotated toward the second posture side, the leaf spring  33  is elastically deformed by rotational force applied to the touch panel body  15 , and the pawl portion  38  moves toward the radial outside of the rotation axis  25  along the circumferential surface  30 . When the pawl portion  38  exceeds the boundary between the recessed groove  29  and the circumferential surface  30 , the pawl portion  38  is elastically restored to the radial inside of the rotation axis  25  and engages with the recessed groove  29  adjacent to the circumferential surface  30 . In the case of rotating the touch panel body  15  from this state toward any of the first posture side or the second posture side, it is necessary to separate the pawl portion  38  from the recessed groove  29 . For that separation, it is necessary to move the pawl portion  38  toward the radial outside of the rotation axis  25  against elastic urging of the leaf spring  33 . Therefore, unless force of further rotation is applied to the touch panel body  15 , the touch panel body  15  is maintained at the rotation angle in a state where the pawl portion  38  engages with the recessed groove  29 . 
     When the touch panel body  15  is further rotated, the leaf spring  33  is elastically deformed, and the pawl portion  38  moves toward the radial outside of the rotation axis  25 . Then, when the pawl portion  38  reaches the boundary between the recessed grooves  29 , the pawl portion  38  is separated from the recessed groove  29  engaging previously. Substantially concurrently with this separation, the pawl portion  38  starts to engage with the next adjacent recessed groove  29  by elastic urging of the leaf spring  33 . In this process, the pawl portion  38  moves toward the radial inside of the rotation axis  25 , and this movement receives the elastic urging of the leaf spring  33 . Therefore, rotation of the touch panel body  15  from the boundary between the recessed grooves  29  to engagement with the next recessed groove  29  can be performed by considerably smaller force than the case of separating the pawl portion  38  from the recessed groove  29 . Then, when the pawl portion  38  engages with the next recessed groove  29 , the touch panel body  15  is maintained at the rotation angle unless force of further rotation is applied to the touch panel body  15  as described above. By such engagement between the recessed groove  29  and the pawl portion  38 , postures of the touch panel body  15  are maintained at any of circumferentially stepwise rotation positions. Then, in the case of moving the stepwise rotation positions, elastic deformation and restoration of the leaf spring  33  are continuously performed with disengagement and engagement between the recessed groove  29  and the pawl portion  38 , and a click feeling is generated in rotation of the touch panel body  15 . 
     Also, as shown in  FIG. 7 , the pawl portion  38  pressure contacts with the first position  61  and the second position  62  of the recessed groove  29  in a state where the pawl portion  38  engages with the recessed groove  29 . Then, the angles θ 1  and θ 2  have a relation of 0°&lt;θ 1 &lt;θ 2 &lt;90° as described above. A ratio, at which rotational force applied to the touch panel body  15  is converted into force of moving the pawl portion  38  to the radial outside of the rotation axis  25  (a direction of being separated from the recessed groove  29 ), varies depending on the angles θ 1  and θ 2 . That is, as the angles θ 1  and θ 2  decrease, force of moving the pawl portion  38  to the radial outside of the rotation axis  25  decreases with respect to force of rotating the touch panel body  15 . 
     Therefore, rotational force F 1  necessary to separate the pawl portion  38  from the recessed groove  29  against the leaf spring  33  and to change the posture of the touch panel body  15  toward the first posture side is greater than rotational force F 2  necessary to change a posture of the touch panel body  15  toward the second posture side in a similar manner (F 1 &gt;F 2 ). Consequently, the touch panel body  15  can relatively easily rotates toward the second posture side, but does not rotate toward the first posture side when greater rotational force is not applied. That is, by a pressing operation applied to the operation area  16 , the touch panel body  15  does not rotate easily even when force of rotating the touch panel body  15  toward the first posture side is applied. 
     Another Embodiment 
     In the above embodiment, the recessed grooves  26  are formed at the touch panel body  15 , and the leaf spring  33  including the pawl portion  38  is provided at the main body  20 . However, the present invention is not limited thereto. For example, the recessed grooves  26  may be formed at the main body  20 , and the leaf spring  33  including the pawl portion  38  may be provided at the touch panel body  15 . In other words, the recessed grooves may be provided at the main body, and the pawl member and the urging member may be provided at the operation panel body. 
     Effect of Embodiments 
     According to the operation unit  13  of the embodiments, since the posture of the touch panel body  15  can be changed, the device can be thinned, especially at the first posture. Also, the multi function device  10  is thinned by disposing the operation unit  13  on an upper surface of the multi function device  10  as described in the embodiments. 
     Also, the tilt mechanism allows the touch panel body  15  to set at maintain in any of postures. Further, according to this tilt mechanism, force F 1  necessary to rotate the touch panel body  15  toward the first posture side becomes greater with respect to force F 2  necessary to rotate the touch panel body  15  toward the second posture side, so that the touch panel body  15  which is relatively easy to rise and is resistant to falling during an operation to the operation area  16  is implemented. 
     Each of the recessed groove  29  and the pawl portion  38  is shaped such that a surface asymmetrical with respect to each of the imaginary lines  42 ,  52  connecting each of the V-shaped vertexes  43 ,  53  and the rotation axis  25  in the cross-section taken along IV-IV, which allows easy design of the angles θ 1  and θ 2  at arbitrary angles while sufficiently ensuring a depth of the recessed groove  29 . By ensuring the depth of the recessed groove  29 , force necessary to rotate the touch panel body  15  can increase and also a click feeling with rotation can increase. Also, the angles θ 1  and θ 2  can be designed at arbitrary angle and thereby, a ratio between forces F 1  and F 2  can be designed widely.