Patent Publication Number: US-8125451-B2

Title: Operation panel and image formation apparatus or electronic equipment using the operation panel

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This is a Division of application Ser. No. 10/732,258 filed Dec. 11, 2003, which claims priority to Japanese Patent Application No. 2003-149914 filed May 27, 2003. The disclosures of the prior applications are hereby incorporated by reference herein in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an operation panel including a display section on which a content of operation inputted at an operation section is displayed and an image formation apparatus or an electronic equipment using this operation panel. 
     2. Description of the Related Art 
     Conventionally, there is known an operation panel which includes a variable mechanism for changing a standing angle of a display section relative to a horizontal plane so as to maintain visibility of the operation panel both at a seated position at which an operator is seated in a wheelchair or the like and at a standing position at which the operator stands up. However, it is not preferable to provide the variable mechanism because the cost of the operation panel is disadvantageously pushed up and an electric wire is possibly broken if the electric wire is bent so as to change the display section standing angle. Further, with the operation panel with the display section standing angle fixed, it is difficult to ensure good visibility both at the wheelchair seated position and at the standing position. 
     In recent years, an operation panel operable even by a physically handicapped person has been on demand, following a request for a universal design of the operation panel. To this end, an operation key operable by a mouth stick held by the mouth of a person with a disabled hand or a head stick fixed at person&#39;s head when used is desired. 
     Japanese Patent Application Laid-Open (JP-A) No. 2002-103732 discloses an operation panel  106  which includes a print key  100  provided to be protruded, made large in size, and made conspicuous by vivid color or display, as compared with other keys  102  and  104 , as shown in  FIG. 14 , so that a user&#39;s attention is drawn to the print key  100 . With this configuration, however, the print key  100  can be made more conspicuous than the other keys  102  and  104  only at the standing position. Therefore, if the operator is seated in the wheelchair, the operator may possibly be unable to visually recognize the print key  100 . 
     JP-A No. 2002-236536 discloses a structure in which, as shown in  FIGS. 15A and 15B , a finger rest section  116  is provided in the middle of an upper button  108 , a lower button  110 , a left button  112 , and a right button  114  and an operator can operate the upper button  108 , the lower button  110 , the left button  112  or the right button  114  without significantly changing a finger position while the operator&#39;s finger continues to stay at this finger rest section  116 . The object of this configuration is, however, to eliminate the operator&#39;s fatigue or feeling troublesome caused by the movement of the finger and not to facilitate easy handling of a mouth stick, a head stick or the like. 
     SUMMARY OF THE INVENTION 
     In light of the above-stated circumstances, it is an object of the present invention to provide an operation panel which can ensure visibility both at a wheelchair seated position and at a standing position and can be easily operated by a handicapped person and to provide an image formation apparatus or electronic equipment using including this operation panel. 
     According to an aspect of the invention, there is provided an operation panel including an operation section; and a display section which displays a content of operation effected at the operation section, wherein the display section is raised, at a predetermined standing angle with respect to a horizontal plane, so that the display section can be visually recognized both from a wheelchair seated position viewpoint and from a standing position viewpoint in accordance with an angle of visibility of the display section, while the operation panel is attached to an apparatus main body. 
     According to the present invention, the display section is raised, at a predetermined standing angle with respect to a horizontal plane, so that the display section can be visually recognized both from a wheelchair seated position viewpoint and from a standing position viewpoint in accordance with an angle of visibility of the display section, while the operation panel is attached to an apparatus main body. Therefore, even when the angle of visibility of the display section is small and the operator is seated in a wheelchair, the operator can visually recognize the display section without fail. Further, at this standing angle of the display section, the operator at the standing position can also visually recognize the display section. Accordingly, the operation panel compliant with a so-called universal design, which imposes no discrimination among the handicapped, the elderly, and the non-handicapped, can be provided. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view which illustrates an image formation apparatus to which an operation panel in one embodiment of the present invention is attached. 
         FIG. 2  is a plan view which illustrates the image formation apparatus to which the operation panel in the embodiment of the invention is attached. 
         FIG. 3  is an explanatory view which schematically illustrates the image formation apparatus to which the operation panel in the embodiment of the invention is attached. 
         FIG. 4  is an explanatory view for evaluating the visibility of a display section of the operation panel in the embodiment of the invention. 
         FIG. 5  is an explanatory view for evaluating the visibility of the display section of the operation panel in the embodiment of the invention. 
         FIG. 6  is an explanatory view for calculating a standing angle of the display section of the operation panel in the embodiment of the invention. 
         FIGS. 7A and 7B  respectively illustrate results of calculations made to obtain the standing angle of the display section of the operation panel in the embodiment of the invention. 
         FIG. 8A  is a perspective view of the operation panel in the embodiment of the invention. 
         FIG. 8B  is an explanatory view which illustrates the relationship between an operation key and a key cover of the operation panel shown in  FIG. 8A . 
         FIG. 9  is a plan view of the operation panel in the embodiment of the invention. 
         FIG. 10  is an explanatory view which illustrates the relationship between the operation key on the operation panel and a stick in the embodiment of the invention. 
         FIG. 11  is another explanatory view which illustrates the relationship between the operation key and the stick in the image formation apparatus in the embodiment of the invention. 
         FIG. 12  is a plan view which illustrates a modified example of the operation panel according to the aforementioned embodiment of the invention. 
         FIG. 13  is a plan view which illustrates another example of the operation panel according to the aforementioned embodiment of the invention. 
         FIG. 14  is a perspective view which illustrates a conventional operation panel; and 
         FIGS. 15A and 15B  are a plan view and a cross-sectional view of the conventional operation panel, respectively. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An image formation apparatus which uses an operation panel in one embodiment of the invention will be described hereinafter. 
     The outline of the image formation apparatus will first be described. As shown in  FIG. 3 , the image formation apparatus  10  consists of an image formation apparatus main body  12  and a paper feeder  14 . The image formation apparatus main body  10  includes an image carrier  16  on a surface of which an electrostatic image is formed by uniformly electrifying the surface of the carrier  16  and emitting an image light thereto, an electrifier  18  which uniformly electrifies the surface of the image carrier  16 , an optical box  20  which irradiates the image carrier  16  with the image light based on image data and which forms a latent image by a difference in electrostatic potential, a developer  22  which selectively transfers a toner onto the latent image to visualize the image, a transfer device  26  which transfers a toner image (an unfixed image) on the surface of the image carrier  16  onto a sheet fed by a resist roller  24 , a fixing device  28  which heats and pressurizes the toner image on the sheet to fixedly melt the toner image, and a cleaner  30  which cleans the toner remaining on the image carrier  16  after the toner image is transferred. 
     The image carrier  16  has a photosensitive layer on its surface and a potential of an exposure section thereof attenuates by exposure after uniform electrification. The electrifier  18  is a rolled member abutted on the image carrier  16 . By applying a voltage between the image carrier  16  and the electrifier  18 , discharge occurs in a very small gap near an abutment portion and the surface of the image carrier  16  is electrified substantially uniformly. As the electrifier, an electrifier that applies a high voltage to an electrode wire and that electrifies the image carrier  16  by corona discharge can be used besides the electrifier described above. 
     The optical box  20  allows a flashing laser light to be scanned relative to a peripheral surface of the image carrier  16  to thereby form the electrostatic latent image based on the image data on the peripheral surface of the image carrier  16 . As the optical box  20 , a device which has a light emitting element such as an LED arranged thereon and which flickers the element based on image data can be used. 
     The developer  22  includes a cylindrical development roller  22 A arranged to be proximate to and face the image carrier  16 . A development bias voltage is applied between the development roller  22 A and the image carrier  16 . By applying the development bias voltage, a development bias electric field is generated between the development roller  22 A and the image carrier  16  and the charged toner is transferred to the exposure section on the image carrier  16 , thereby forming a visible image. 
     The transfer device  26  is a rolled member provided to face the image carrier  16 . By forming a transfer electric field between the transfer device  26  and the image carrier  16 , the toner image is transferred onto a passing sheet. 
     After the toner image is transferred onto the sheet by the transfer device  26 , the sheet is separated from the image carrier  16 . The separated sheet is transported to the fixing device  28 , heated, pressurized and fixed by the fixing device  28 , and discharged onto a discharge tray  44 . Further, after the toner image is transferred onto the sheet, the surface of the image carrier  16  is cleaned by the cleaner  30  in preparation for the next image forming processing. 
     The paper feeder  14  which feeds sheets into the image formation apparatus main body  12  one by one is provided below the image formation apparatus main body  12 . This paper feeder  14  includes detachable trays  32 ,  34 ,  36 , and  38  which can be pulled out in an opposite direction to a sheet feed-out direction. 
     The tray  32  has a capacity of 150 sheets. The tray  34  has a capacity selectable between a capacity of 250 sheets and a capacity of 550 sheets. The trays  36  and  38  are optional and each has a capacity of 550 sheets. 
     Paper feed rollers  40  for feeding sheets from the trays  32 ,  34 ,  36 , and  38  are provided near tip end portions of the trays  32 ,  34 ,  36 , and  38 , respectively. Handling members (not shown) pressure-fitted by the paper feed rollers  40  are provided on tip end sides of the trays  32 ,  34 ,  36 , and  38 , respectively, thereby feeding the sheets in the tray  32 ,  34 ,  36  or  38  one by one. 
     The sheet fed from the paper feeder  14  is transported to a toner image transfer position at a predetermined timing by the resist roller  24  provided near the paper feeder  14 . 
     If double sided printing is performed, the sheet having an image fixed to one side is transported to a double sided printing transport unit  48  by changing a transport direction by a switching gate  46  without directly discharging the sheet to the discharge tray  44 . In this double sided printing transport unit  48 , transport rollers  52  provided along a transport path  50  transport the sheet to the resist roller  24  again with the sheet turned inside out, an image is transferred and fixed onto a rear side of the sheet, and then the sheet is discharged to the discharge tray  44 . 
     An extension tray  45  is provided on a front surface side of the image formation apparatus  10  so that the tray  45  can be freely input and output. When a large-sized sheet (which is a sheet having a large sheet length such as an A3 or Legal size sheet) is used, by drawing the extension tray  45  out, the sheet is prevented from falling down from the image formation apparatus  10 . 
     An operation panel in one embodiment of the invention will next be described. 
     As shown in  FIGS. 1 to 3 , the operation panel  54  is provided at a front (the lower side in  FIGS. 1 and 2 ) right corner on a front top surface  12 A of the image formation apparatus  12 . The top surface of the image formation apparatus main body  12  is inclined so that the front surface  12 A, which is at the front side of the apparatus main body, is lower than the rear top surface, which is at the rear side of the apparatus main body (see  FIG. 1 ). The operation panel  54  is inclined so that the front portion thereof, which is at the front side of the apparatus main body, is lower than the rear portion thereof, which is at the rear side of the apparatus main body. 
     The operation panel  54  consists of an operation section  56  which sets an operation mode (a print mode, a power saving mode, or the like) of the image formation apparatus  10  and a display section  58  which displays the operation mode set by the operation section  56 . The display section  58  is arranged to be located outside of a discharge region to which sheets are discharged, and raised at about 50 degrees relative to the horizontal plane (as will be described later). 
     The discharge region refers to a region to which the sheets are discharged. Specifically, the discharge region represents regions of the top surface  12 A and the extension tray  45  of the image formation apparatus main body  12 A, which regions could be covered by a discharged sheet projecting from the discharge tray  44 . By arranging the display section  58  outside of the discharge region, it is possible to prevent the display section  58  from being covered with the discharged sheets and thus ensure the visibility of the display section  58 . 
     As shown in  FIG. 4 , a display section height (x) differs according to sizes and numbers of the paper feed trays. If the tray  34  has a capacity of 250 sheets, the display section height (x) of the image formation apparatus  10  is 990 millimeters (290 millimeters of a height to the display section  58  of the image formation apparatus  10 +700 millimeters of a height of a disk  59  according to Japanese disk standards). If the tray  34  has a capacity of 550, the display section height (x) of the image formation apparatus  10  is 1020 millimeters (320 millimeters of a height to the display section  58  of the image formation apparatus  10 +700 millimeters of the height of the disk  59  according to Japanese disk standards). 
     If the optional tray  36  having a capacity of 550 is attached to the image formation apparatus  10 , the display section height (x) of the image formation apparatus  10  is 1115 millimeters (415 millimeters of a height to the display section  58  of the image formation apparatus  10 +700 millimeters of the height of the disk  59  according to Japanese disk standards). If the tray  38  having a capacity of 550 sheets is further attached to the image formation apparatus  10  in addition to the tray  36 , the display section height (x) is 1205 millimeters (505 millimeters of a height to the display section  58  of the image formation apparatus  10 +700 millimeters of the height of the disk  59  according to the Japanese disk standards). 
     As shown in  FIGS. 4 and 5 , when a standing angle of the display section  58  relative to the horizontal plane is about 50 degrees, the largest angle of visibility, which is 80 degrees (with an angle α of 40 degrees formed between the line normal to the display surface of the display section  58  and the visibility range limit), is represented by a symbol b. In this condition, if the visibility of the display section  58  is evaluated at the standing position with the display section height (x) set at 1020 millimeters, a line-of-sight angle is 70 degrees relative to the horizontal plane when a height of the standing position viewpoint is 1778 millimeters (which is an upper limit of the height of the operator&#39;s eye at the standing position for Japanese male users (ages: 20 to 69 years old; and a range of objectives: 95 percents of the objectives)). Therefore, even if the standing angle of the display section  58  is set at 60 degrees, the aforementioned line-of-sight angle falls within the range of the angle of visibility of 80 degrees (a range a). 
     On the other hand, if the operator looks into the display section  58  from the wheelchair seated position (at the height of the seated position viewpoint of 1012.6 millimeters, which height is a lower limit of the height of the operator&#39;s eye at the seated position for Japanese female users(ages: 20 to 69 years old; and a range of objectives: 95 percents of the objectives)) (i.e., at a height of 1012.6 mm+30 mm=1042.6 mm), the operator can visually recognize the display section  58  even when the standing angle of the display section  58  is 40 degrees (i.e., when the angle of visibility is in a range c). However, in this condition, if the display section height (x) of the image formation apparatus  12  exceeds 1115 millimeters, the display section  58  is located out of the visible range and the operator can no longer visually recognize the display section  58 . 
     Next, a method of setting the standing angle A of the display section  58  relative to the horizontal plane will be described. 
       FIG. 6  illustrates the relationship between the standing angle A of the display section and the display section height (x). If the standing angle A of the display section  58  satisfies the following expression, it is possible to ensure the visibility of the display section  58  both at a height (y) of the operator&#39;s eye at the wheelchair seated position and at a height (z) of the operator&#39;s eye at a position at which a non-handicapped person stands up. 
     
       
         
           
             
               
                 
                   
                     90 
                     + 
                     α 
                     - 
                     
                       
                         tan 
                         
                           - 
                           1 
                         
                       
                       ⁢ 
                       
                         
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                           - 
                           x 
                         
                         L 
                       
                     
                   
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                   A 
                   ≥ 
                   
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                     - 
                     α 
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                           - 
                           y 
                         
                         L 
                       
                     
                   
                 
               
               
                 
                   ( 
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     In Expression (1), A represents the standing angle of the display section (in degrees), α represents an angle (in degrees) formed between the line normal to the display surface of the display section and the visibility range limit, x represents the display section height, y represents the height of the seated position viewpoint, z represents the height of the standing position viewpoint, and L is a horizontal distance from the display section  58  to the operator&#39;s eye. 
     As shown in  FIG. 7A , a calculation result based on Expression (1) demonstrates that, at the angle of visibility of 80° (i.e., with the angle α formed between the line normal to the display surface of the display section and the visibility range limit being 40°), if the display section height x is 1115 millimeters or more, the standing angle A does not satisfy Expression (1). However, as shown in  FIG. 7B , at the angle of visibility of 120° (with the angle α formed between the line normal to the display surface of the display section and the visibility range limit being 60°), even if the display section height x is 1205 millimeters, the standing angle A satisfies Equation (1). 
     Consequently, if the angle of visibility of the display section  58  is 80°, the standing angle of the display section  58  is preferably in a range of about 45 to 60 degrees. If the angle of visibility is 120°, the standing angle is preferably in a range of about 35 to 85 degrees. 
     The standing angle of the display section  58  can be further specified according to the display section height x. In the present embodiment, the angle of visibility of the display section  58  is set at 80 degrees and the standing angle thereof relative to the horizontal plane is set at about 50 degrees, as an example, so that the operator can visually recognize the display section  58  until the display height reaches 1020 millimeters, even while the operator is seated in the wheelchair. 
     Meanwhile, as shown in  FIGS. 8A ,  8 B, and  9 , the operation section  56  of the operation panel  54  is provided with a key cover  60  having a flat plate-like shape. The key cover  60  is arranged to be flush with or below the top surface  12 A of the image formation apparatus main body  12  so that the key cover  60  does not protrude from the top surface  12 A of the main body  12 . In addition, a plurality of holes  60 A are formed in the key cover  60  and operation keys  62  for setting the operation mode are arranged in the respective holes  60 A. 
     In the present embodiment, the key cover  60  is provided separately from the image formation apparatus main body  12 . However, the key cover  60  need not be always separated from the image formation apparatus main body  12  and may be provided integrally with the image formation apparatus main body  12 . In the latter case, even if the key cover  60  is not arranged to be flush with or below the top surface  12 A of the image formation apparatus main boy  12 , there is no fear that the tip end of the discharged sheet is caught in the cover  60 . 
     The operation keys  62  are classified to visual recognition keys (a menu key  62 C, a selection key  62 D, etc.) to be operated while the operator is viewing the display section  58  and non-visual recognition keys (an online key  62 A, a print stop key  62 B, etc.) which do not require the operator to view the display section  58  during the operation thereof. The visual recognition keys (the menu key  62 C, the selection key  62 D, etc.) are arranged out of a projection region of the display section whereas the non-visual recognition keys (the online key  62 A, the print stop key  62 B, etc.) are arranged within the projection region. 
     As shown in  FIGS. 8A ,  8 B, and  10 , each of the operation keys  62  includes a curved, inclined convex portion  63 B a having a protruding central portion and provided on a tip end of a cylindrical body  63 A. The inclined convex portion  63 B is arranged to be flush with or below a surface of the key cover  60  so as not to protrude from the surface of the key cover  60 . 
     If depths of the operation keys  62  are too large, the key cover  60  around the keys  62  obstructs the operator when the operator depresses one of the operation keys  62  with an operator&#39;s finger and the operativity is deteriorated. Therefore, in view of irregularity of dimensions and the like, it is preferable to set a depth at which a top of the inclined convex portion  63 B is positioned at about 0.5 millimeters from the surface of the key cover  60 . 
     Further, an inverted cone-shaped bank portion  64  is provided in each hole  60 A of the key cover  60 . A rising part P 1  (a boundary between a perpendicular surface and an inclined surface) on a lower side of the bank portion  64  is set higher than a rising part P 2  (a boundary between the cylindrical body  63 A and the inclined convex portion  63 B) of the inclined convex portion  63 B. 
     A tip end of a stick  66  such as a mouth stick or a head stick (which is held in the mouth or fixed to the head by a person having a disabled hand when the person operates a keyboard or the like) having a diameter of 3.5 millimeters (⅛ inches) is caught in between the bank portion  64  and an outer peripheral surface of the operation key  62 . 
     Even if the stick  66  is inclined at, for example, 30±5 degrees relative to the surface of the key cover  60  (the angle at which the stick  66  is inclined will be expressed as δ hereinafter), the operation key  62  can be reliably pushed down by the stick  66 . Further, even if the stick  66  slips over the top of the inclined convex portion  63 B, the operation key  62  can reliably be pushed down due to the stick  66  being blocked by the rear side of the bank portion  64 . 
     If a tilt angle of the bank portion  64  is expressed as β and a static friction factor between the stick  66  and the bank portion  64  is expressed as μ, the tilt angle β and the static friction factor μ are preferably set to satisfy the following expression:
 
β&lt;tan −1 μ+δ  (2)
 
     Namely, while assuming that a pressing force with which the stick  66  pressurizes the bank portion  64  is F, if a maximum frictional force, i.e., Fcos (β−δ)×μ, which acts on the bank portion  64 , is higher than an upward component force Fsin (β−δ), of the pressing force F, which component force acts along the bank portion  64 , the stick  66  does not slide on the bank portion  64  and the following relationships are, therefore, satisfied: 
     
       
         
           
             
               
                 
                   
                     F 
                     ⁢ 
                     
                         
                     
                     ⁢ 
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                     ⁢ 
                     
                         
                     
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                       ( 
                       
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                   &gt; 
                   
                     F 
                     ⁢ 
                     
                         
                     
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                     sin 
                     ⁢ 
                     
                         
                     
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                       ⁢ 
                       
                           
                       
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                     ⁢ 
                     
                         
                     
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     Here, if the tilt angle β of the bank portion  64  is smaller (sharper), a trough formed by the bank portion  64  is deeper. Accordingly, the magnitude by which the stick  66  falls down is larger and the operativity is deteriorated. In addition, with small tilt angle β, when the stick  66  abuts on the bank portion  64 , an impact applied to the stick  66  increases. Therefore, it is preferable that the tilt angle β of the bank portion  64  is set as large (gentle) as possible within a range in which the stick  66  does not slide on the bank portion  64 . 
     On the other hand, a tangential angle γ formed between the vertical direction and a tangenitial line at a point at which the tip end of the stick  66  abuts on the operation key  62  is preferably set, as in the case of the tilt angle β of the bank portion  64 , to satisfy the following expression so that the stick  66  can push the operation key  62  without sliding on the outer peripheral surface of the operation key  62 :
 
γ&lt;tan −1 μ′+δ  (6)
 
     In the expression (6), μ′ is the static friction factor between the stick  66  and the operation key  62 . 
     Furthermore, as shown in  FIG. 11 , a curved concave portion  68  with which the tip end of the stick  66  can be engaged may be provided on the top of the inclined convex portion  63 B of the operation key  62  so that the stick  66  can depress the operation key  62  without sliding on the outer peripheral surface of the operation key  62 . By so providing, the operation key  62  can be depressed with the tip end of the stick  66  caught in the concave portion  68 . 
     A width W of the concave portion  68  is preferably 3.5 millimeters or more so that the tip end of the stick  66  can be caught in the concave portion  68 . Meanwhile, since the operation key  62  is recessed as compared with the surface of the key cover  60 , the bank portion  64  of the key cover  60  may serve as an obstacle when the operator pushes the operation key  62  down with his/her finger, to thereby deteriorate the controllability. Therefore, as shown in  FIG. 10 , the largest distance L between the facing bank portions  64  is preferably kept ten millimeters or more. 
     This largest distance L need not be kept at 10 millimeters in either lengthwise or crosswise. It suffices to secure the 10 mm or more distance only in the crosswise direction viewed from the front side of the image formation apparatus  10 . With this arrangement, even if the image formation apparatus  10  is small in size, it is still possible to ensure the good operativity of the operation key  62  substantially equal to that in the large-sized image formation apparatus  10 . 
     It is also preferable that a distance L 1  from a boundary between the surface of the key cover  60  and the bank portion  64  to the center of the operation key  62  is set at 3.5 millimeters or more so that the tip end of the stick  66  can reliably be caught in between the bank portion  64  and the operation key  62 . 
     As shown in  FIG. 9 , a distance L 2  between one boundary of one bank portion  64  with respect to the surface of the key cover  60  and the other boundary of the other bank portion  64  with respect to the surface of the key cover  60 , is set at six millimeters or more. Further, a distance L 3  from one boundary between one bank portion  64  and the surface of the key cover  60 , to the center of the other operation key  62 , is set at nine millimeters or more. 
     The function of the image formation apparatus  10  in the embodiment of the invention will next be described. 
     As shown in  FIGS. 1 and 2 , by arranging the display section  58  on the front face side of the image formation apparatus main body  12 , the display section  58 , the visibility of which can be ensured both at the seated position at which the operator is seated in the wheelchair or the like and at the standing position, can be obtained relatively easily. Specifically, by raising the display section  58  relative to the horizontal plane, the operator can visually recognize the display section  58  even while the operator is seated in, for example, the wheelchair as shown in  FIGS. 4 and 5 . 
     If the display section  58  consists of a liquid crystal having an angle of visibility of 80 degrees (with an angle formed between the line normal to the display surface of the display section and the visibility range limit being 40 degrees), the display section  58  is raised at about 50 degrees relative to the horizontal plane, so that the visibility both at the wheelchair seated position at which a handicapped person is seated in the wheelchair and at the standing position at which the non-handicapped person stands up can be ensured. Accordingly, the operation panel in a so-called universal design, which causes no discrimination among the handicapped, the elderly, and the non-handicapped people, can be provided. 
     As shown in  FIG. 9 , by classifying the operation keys  62  to the visual recognition keys (the menu key  62 C, the selection key  62 D, etc.) operated while the operator is viewing the display section  58  and the non visual recognition keys (the online key  62 A, the print stop key  62 B, etc.) which do not require the operator to view the display section  58  during the operation thereof, and by arranging the visual recognition keys (the menu key  62 C, the selection key  62 D, etc.) outside of the projection region of the display section  58 , the disadvantage that the display section  58  is hidden by the operator&#39;s hand when the operator operates the visual recognition key and the operation is thereby disturbed does not occur. 
     Further, the distance between the operation keys  62  is set relatively wide. Therefore, even if a physically handicapped person operates the operation section  56 , it is possible to prevent such a malfunction as pushing a plurality of operation keys  62  simultaneously from occurring, whereby the controllability of the operation keys  62  can be improved. 
     As shown in  FIGS. 8A and 8B , by arranging the upper surface of each operation key  62  below or to be flush with the surface of the key cover  60 , it is possible to prevent the operation key  62  from protruding from the surface of the key cover  60 . 
     As a result, when the operator operates the operation key  62  with the stick  66  by moving the tip end of the stick  66  along the surface of the key cover  60 , good operativity is ensured in the operation key  62  which is flush with or below the surface of the key cover  60  since there is no possibility that the operation key  62  disturbs the movement of the stick  66 , as compared with the operation key protruding from the surface of the key cover  60 . 
     Further, as shown in  FIGS. 8A ,  8 B, the inverted cone-shaped bank portion  64  is provided in each hole  60 A of the key cover  60 , so that the stick  66  can depress the operation key  62  with the tip end of the stick  66  caught in between the bank portion  64  and the outer peripheral surface of the operation key  62 . 
     As described above, by allowing the operator to operate the operation key  62  even with the stick  66 , the operation panel compliant with the universal design can be provided and an office environment friendly even to the handicapped can be provided. 
     Further, by providing the curved, inclined convex portion  63 B having the protruding central portion, on the tip end of the cylindrical body  63 A of each operation key  62 , and providing the inverted cone-shaped bank portion  64 A in each hole  60 A of the key cover  60 , the movement of the tip end of the stick  66  can be made more smooth. This smooth movement reduces the impact applied to the stick  66  and ensure good operativity. 
     Yet further, by setting the rising part P 1  (the boundary between the perpendicular portion and the inclined portion) on the lower side of the bank portion  64  higher than the rising part P 2  (the boundary between the cylindrical body  63 A and the inclined convex portion  63 B) of the inclined convex portion  63 B, it is possible to prevent the stick  66  from being caught in the outer peripheral surface of the operation key  62 . 
     Yet further, by providing the concave portion  68 , with which the tip end of the stick  66  can be engaged, on the top of the inclined convex portion  63 B of the operation key  62 , the operator can push the operation key down by making the tip end of the stick  66  be caught by the concave portion  68 , even in cases, for example, in which an outside diameter of the stick  66  is larger than 3.5 millimeters or an angle δ of the stick  66  with respect to the surface of the key cover  60  is larger than 30±5 degrees. 
     As described above, by arranging various methods of operatively pushing the operation key  62  with the stick  66 , the operation panel  54  can be made still easier to handle. 
     In the present embodiment, the standing angle of the display section  58  relative to the horizontal plane is set at about 50 degrees. However, this angle (50 degrees) is only an example. The standing angle of the display section  58  may change in accordance with the angle of visibility of the display section  58 . In short, it suffices as long as the standing angle of the display section  58  can achieve visibility of the display section  58  both at the wheel chair-seated position and the standing position at which the non-handicapped person stands up, and the standing angle of the display section  58  is not limited to about 50 degrees. 
     Further, in the embodiment of the invention, the visual recognition keys (the menu key  62 C, the selection key  62 D, etc.) are arranged outside of the projection region of the display section  58 , so that the operation section  58  is not hidden by the operator&#39;s hand when the operator operates the visual recognition key. However, the arrangement of the visual recognition keys is not limited to this arrangement, as long as a situation in which the operator&#39;s had hides the display section  58  is prevented. 
     For example, as shown in  FIG. 12 , an operation panel  70  may be arranged at the left front corner on the top surface  12 A of the image formation apparatus main body  12 . In the example of  FIG. 12 , a display section  72  is arranged on a left rear side of the operation panel  70  and the visual recognition keys (the menu key  62 C, the selection key  62 D, etc.) are arranged at the right-hand side of the projection region of the display section  72 . With this arrangement, good operativity is ensured because an operator&#39;s right hand does not cross the operator&#39;s sight when the operator operates the operation section with his/her right hand. 
     Further, as shown in  FIG. 13 , only an operation section  76  of an operation panel  74  may be arranged at the front right corner portion of the top surface  12 A of the image formation apparatus main body  12  and a display section  78  may be provided in a right rear portion of the image formation apparatus main body  12 . 
     In the example of  FIG. 13 , by inclining the top surface of the image formation apparatus main body  12  so that the front top surface  12 A, which is at the front side of the apparatus main body, is lower than the rear top surface, which is at the rear side of the apparatus main body, the visibility can be ensured both at the wheelchair seated position and the standing position, even if the display section  78  is arranged in the rear portion of the image formation apparatus main body  12 . 
     In the example of  FIG. 13 , whether the operation key is operated by the operator&#39;s right hand or left hand, the display section  78  is never hidden by the operator&#39;s hand. Further, as the operation section  76  and the display section  78  are arranged so as to be on the same line along the operator&#39;s sight, no operational disadvantage occurs even if the operation &#39;section  76  and the display section  78  are provided separated from each other. 
     In the present embodiment, in the case in which the display section  58  consists of the liquid crystal having an angle of visibility of 80 degrees (i.e., with an angle formed between the line normal to the display surface of the display section  58  and the visibility range limit being 40 degrees), the display section  58  is raised at about 50 degrees relative to the horizontal plane, so that visibility can be ensured both at the wheelchair seated position and at the standing position at which the non-handicapped person stands up (feature  1 ). In addition, by providing the inverted cone-shaped bank portion  64  in each hole  60 A of the key cover  60  such that the operation key  62  can be pushed down with the tip end of the stick  66  being caught between the bank portion  64  and the outer periphery of the operation key  62 , the operation panel compliant with the universal design, which causes no discrimination among the handicapped, the elderly, and the non-handicapped, can be provided (feature  2 ). However, the operation panel of the present invention need not always have the aforementioned two features, and it suffices if the operation panel has at least one of the two features. 
     Further, in the embodiment of the invention, the angle δ formed between the stick  66  and the surface of the key cover  60  is 30±5 degrees. However, this angle is only an example and the angle δ is not limited to 30±5 degrees. 
     Furthermore, the operation keys  62  and the bank portion  64  may both be made of plastic. In this case, the static friction factor μ of each operation key  62  can be set substantially equal to the static frictional factor μ′ of the bank portion  64 , so that the angles β and γ (see  FIG. 10 ) are substantially equal to each other. Besides, if each operation key  62  is made of a high friction member such as rubber, it is possible to set the angle γ larger than the angle β. 
     In the present embodiment, the image formation apparatus  10  has been described. However, the present invention is not limited to the operation panel  54  of the image formation apparatus  10 . That is, the present invention may be applied to an operation panel of an electronic equipment such as a facsimile machine, a telephone, a washing machine, a microwave oven, a keyboard, or an electronic calculator. 
     In short, according to the present invention having the above-described structure, even if the angle of visibility of the display section is relatively small, the operator can visually recognize the display section while the operator is seated in the wheelchair. The display section is raised with respect to the horizontal level by a standing angle at which the operator can visually recognize the display section at the standing position seated position, as well. As a result, the operation panel compliant with the so-called universal design, which causes no discrimination among the handicapped, the elderly, and the non-handicapped, can be provided.