Abstract:
An image forming apparatus including an image forming apparatus body, a cassette attaching section having a media supplying roller, a media cassette with a loading plate and a supporting section, a first ground conducting route and a second ground conducting route. The first ground conducting route conducts static electricity charged on the media when the media stacked in the media cassette is spaced away from the media supplying roller. A conducting portion of the first ground conducting route maintains the media cassette in an electrically disconnected state when the media passes through an opening in the cassette attaching section and reconfigures the media cassette from the electrically disconnected state to an electrically connected state before the media cassette reaches a first position. The second ground conducting route conducts static electricity charged on the media when the media cassette is in the first position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a division of published U.S. patent application Ser. No. 13/072,323 filed Mar. 25, 2011, which is a continuation of U.S. Pat. No. 7,929,879 filed Oct. 10, 2007, which is a continuation U.S. patent application Ser. No. 11/014,576 filed Dec. 16, 2004, now abandoned, the disclosures of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an image forming apparatus to prevent trouble caused by static electricity. 
     2. Description of Related Art 
     In some kinds of image forming apparatuses such as what uses an electrophotographic method, an electrostatic method, or a magnetoelectric method; toner images are formed on surfaces of photosensitive drums etc. based on image information received from host devices. These toner images are transcribed onto recording media supplied from media supplying units. And, these toner images are fixed with heat in fixing units, so as to form images. In the media supplying units, media contained in media cassettes are pressed to media supplying rollers, so as to be supplied. Inside of the media cassettes, loading plates to be pushed to the media supplying rollers are provided. And, the recording media are loaded on these loading plates. In these states, the loading plates with media are pushed or moved toward the media supplying rollers. Then, the recording media are pressed to the media supplying rollers. And, each medium is separated and supplied one by one by a conveying force of media supplying rollers with friction between the rolls and separating rubbers. 
     In the media supplying apparatus, static electricity is generated by friction such as friction between the recording medium and the media supplying roller, friction between the recording medium and the separating rubber, or friction between the recording media themselves, when the recording media are conveyed. Moreover, in some cases, static electricity is already charged on the recording medium, before the media supplying unit is attached to the image forming apparatus. Such static electricity can flow in unexpected routes. Especially, in an image forming apparatus of recent years, many component parts are made of resin. Therefore, much static electricity is likely to be generated on the recording medium loaded on a media cassette made of resin. The static electricity flowing in unexpected routes becomes a noise of electric current that causes inconvenience such as drop of graphical quality, malfunction of the apparatus, or electric shocks to operators (c.f. JP 7-237783). 
     Therefore, the present invention is made to remove inconvenience such as drop of graphical quality, malfunction of the apparatus, or electric shocks to operators caused by static electricity flowing in unexpected routes becoming a noise of electric current. 
     BRIEF SUMMARY OF THE INVENTION 
     According to one aspect of the present invention, there is provided an image forming apparatus having: a first ground conducting route for conducting static electricity charged on a recording medium through an outer frame of a media supplying unit to a grounding point, and a second ground conducting route for conducting static electricity charged on a recording medium through a media supplying roller to a grounding point. 
     And in the image forming apparatus mentioned above: the first ground conducting route is formed when the media supplying unit is on a way to a position where the media supplying unit is attached to the image forming apparatus body, so as to conduct static electricity charged before the media supplying unit is attached to the image forming apparatus body; and the second ground conducting route conducts static electricity charged after the media supplying unit is attached to the image forming apparatus body. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The foregoing summary, as well as the following detailed description of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. 
       In the drawings: 
         FIG. 1  is an explanatory diagram showing a chief elements of a structure (before attaching) of Embodiment 1; 
         FIG. 2  is an explanatory diagram showing an image forming apparatus; 
         FIG. 3  is a slant viewed diagram showing a media cassette and its attaching portion of Embodiment 1; 
         FIG. 4  is a slant viewed diagram showing a loading plate of Embodiment 1; 
         FIG. 5  is an explanatory diagram showing a chief elements of a structure (a first state of combination) of Embodiment 1; 
         FIG. 6  is an explanatory diagram showing a chief elements of a structure (a second state of combination) of Embodiment 1; 
         FIG. 7  is an explanatory diagram showing a chief elements of a structure (a state of completed attachment) of Embodiment 1; 
         FIG. 8  is an explanatory diagram showing a chief elements of a structure (before attaching) of Embodiment 2; 
         FIG. 9  is a slant viewed diagram showing a media cassette and its attaching portion of Embodiment 2; 
         FIG. 10  is a slant viewed diagram showing a loading plate of Embodiment 2; 
         FIG. 11  is an explanatory diagram showing a chief elements of a structure (a first state of combination) of Embodiment 2; 
         FIG. 12  is an explanatory diagram showing a chief elements of a structure (a second state of combination) of Embodiment 2; 
         FIG. 13  is an explanatory diagram showing a chief elements of a structure (a state of completed attachment) of Embodiment 2; 
         FIG. 14  is an explanatory diagram showing a chief elements of a structure (before attaching) of Embodiment 3; 
         FIG. 15  is a slant viewed diagram showing a media cassette and its attaching portion of Embodiment 3; 
         FIG. 16  is a slant viewed diagram showing a loading plate of Embodiment 3; 
         FIG. 17  is an explanatory diagram showing a chief elements of a structure (a first state of combination) of Embodiment 3; 
         FIG. 18  is an explanatory diagram showing a chief elements of a structure (a second state of combination) of Embodiment 3; 
         FIG. 19  is an explanatory diagram showing a chief elements of a structure (a state of completed attachment) of Embodiment 3; 
         FIG. 20  is an explanatory diagram showing a chief elements of a structure (before attaching) of Embodiment 4; 
         FIG. 21  is a slant viewed diagram showing a media cassette and its attaching portion of Embodiment 4; 
         FIG. 22  is a slant viewed diagram showing a loading plate of Embodiment 4; 
         FIG. 23  is an explanatory diagram showing a chief elements of a structure (a first state of combination) of Embodiment 4; 
         FIG. 24  is an explanatory diagram showing a chief elements of a structure (a second state of combination) of Embodiment 4; and 
         FIG. 25  is an explanatory diagram showing a chief elements of a structure (a state of completed attachment) of Embodiment 4. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Embodiment 1 
     Configuration 
       FIG. 1  is an explanatory diagram showing a chief elements of a structure (before attaching) of Embodiment 1. 
       FIG. 1  shows a diagram of an image showing a positional relation of chief component parts only, seeing inside of an apparatus through a side wall of the apparatus&#39; body, so as to refer to explain a structure, a function and an operation of Embodiment 1. 
     As shown in  FIG. 1 , chief component parts of Embodiment 1 are an image forming apparatus body  1  and a media cassette  2 . The image forming apparatus body  1  comprises a media supplying roller  9 , a pushing out member  10 , a release portion  11  and a conveyance path  15 . The media cassette  2  (media supplying unit) comprises a loading plate  3 , a conducting plate  4 , a pushing up member  5 , a plate holding portion  6 , an L shaped crook portion  7 , an outer frame  8 , a separating rubber  12 , a coil spring  13  and a loading plate fulcrum  14 . 
     Before explaining a structure, a function and an operation of Embodiment 1 referring to  FIG. 1 , overall structure and operation of an image forming apparatus to which the present invention is applied (Embodiment 1 to 4) are explained. 
       FIG. 2  is an explanatory diagram showing an image forming apparatus. 
       FIG. 2  shows a diagram of an image showing chief component parts only, seeing an inside of the apparatus through a side wall of the apparatus&#39; body, so as to refer to explain an overall structure and operation of the image forming apparatus to which the present invention is applied. 
     As shown in  FIG. 2 , a pile of recording media  20  are contained in a media cassette  2 . Each of recording media  20  are supplied by a combination of a media supplying roller  9  and a separating rubber  12  one by one from the media cassette  2  to a conveyance path  15 . Then, a static electricity is generated by frictions such as a friction between each of recording media  20  and a media supplying roller  9 , a friction between each of recording media  20  and a separating rubber  12 , and a friction between recording media  20  themselves. And, how to discharge this static electricity is a subject of the present invention. 
     Each of recording media  20  supplied to a conveyance path  15  separated one by one, are sensed by an intake sensor  21 . After that, each of recording media  20  are sent by a resist roller  22  to a conveying belt  23  which is a portion of the conveyance path  15 . When each of recording media  20  pass at a halfway point sensor  37 , an image forming section  36  starts forming a toner image. This toner image is transcribed by a transcribing roller  24  to each of recording media  20  conveyed on a conveying belt  23 . 
     Formation of a toner image inside of the image forming section  36 , is performed as follows. A surface of a photosensitive drum  25  rotating in a direction shown by an arrow, is charged negative by a charging roller  26 . When this negative charged portion comes to a position under an exposing head  27 , the exposing head  27  radiates light, so as to form electrostatic latent image at the charged portion based on an image data. This electrostatic latent image is developed by a developing roller  29  provided in a developer  28 , so as to be a toner image. This toner image is transcribed by a transcribing roller  24  to one of recording media  20 . Then, toner remained on the surface of the photosensitive drum  25  is removed by a cleaning unit  30 . 
     The toner image transcribed by the transcribing roller  24  to one of recording media  20 , is fixed with a treatment of high temperature and high pressure by a heating roller  31  and a backup roller  32 . The one of recording media  20  on which a toner image is fixed, is let out by an outlet roller  33  onto a medium stack  34 , an outlet of the one of recording media  20 , is detected by an outlet sensor  35 . 
     As mentioned above, an outline of the overall structure and operation of an image forming apparatus, has been explained. And, the chief component parts shown in  FIG. 1  referred to above, will be explained in detail, referring to a slant view corresponding to Embodiment 1. 
       FIG. 3  is a slant viewed diagram showing a media cassette and its attaching portion of Embodiment 1. 
       FIG. 3  shows a slant view of a media cassette and a slant view of a portion of an image forming apparatus body where the media cassette is attached. 
     When a user is going to detach the media cassette  2  from the image forming apparatus body  1 , he touches his hand to a handle  42 . Then, the handle  42  rotates around a handle fulcrum  43  which is supporting the handle  42 . And, a latch  41  is taken off. Then, the media cassette  2  is pushed out by a pushing out member  10  provided in the image forming apparatus body  1 . 
     A loading plate  3  is provided in the media cassette  2 . And, a pile of recording media (not shown in  FIG. 3 ) are loaded on the loading plate  3 . Then, a pair of side guides  44  hold the recording media  20  (shown in  FIG. 1 ) at longitudinal sides of them, and a tail guide  46  holds a lateral side of them, so as not to scatter in the media cassette  2 . 
     Thus, the recording media (not shown in  FIG. 3 ) held in the media cassette  2  and loaded on the loading plate  3 , are pressed by a pushing up member  5  to the media supplying roller  9  provided in the image forming apparatus body  1 , after the media cassette  2  is attached to the image forming apparatus body  1 . The loading plate  3  is supported by a loading plate fulcrum  45 , so as to rotate up and down around the loading plate fulcrum  45 . 
       FIG. 4  is a slant viewed diagram showing a loading plate of Embodiment 1. 
       FIG. 4  shows a slanted view of a backside of the loading plate  3  which is taken apart from the image forming apparatus body  1 . 
     As shown in  FIG. 4 , a loading plate  3  with a pile of recording media  20  is pressed to a media supplying roller  9  by a pushing up member  5  comprising a coil spring. 
     Moreover, a release frame  16  is made for containing a force of a pushing up member  5  by engaging a plate holding portion  6  with an L shaped crook portion  7  formed on the backside of the loading plate  3 , when the media cassette  2  is not attached to the image forming apparatus body  1 . Here, the release frame  16  with the plate holding portion  6  is provided at a prescribed portion of an outer frame (shown in  FIG. 3 ). When the media cassette  2  is attached to the image forming apparatus body  1 , a release portion  11  formed on an inner base of the image forming apparatus body  1  (shown in  FIG. 1 ) releases the engagement between the plate holding portion  6  and the L shaped crook portion  7 , with pressing a coil spring  13 . 
     Returning to  FIG. 1 , a function and an operation of Embodiment 1 will be described. 
     As shown in  FIG. 1 , the recording media  20  are loaded on the loading plate  3  piling up on it. The recording media  20  are held by a pair of side guides  44  ( FIG. 3 ) at longitudinal sides. And, they are held by a tail guide  46  at a lateral side. Thus, they do not scatter in the media cassette  2 . In  FIG. 1 , a force of a pushing up member  5  is contained by engaging a plate holding portion  6  with an L shaped crook portion  7  formed on the backside of the loading plate  3 , as the media cassette  2  is not attached to the image forming apparatus body  1 . 
     A conducting plate  4  is provided, so that one end portion of it contacts with at least either of said recording medium  20  or said loading plate  3  and that other end of it is projected to outside of the media cassette  2 . 
       FIG. 5  is an explanatory diagram showing a chief elements of a structure (a first state of combination) of Embodiment 1. 
       FIG. 5  shows a state that a conducting plate  4  of the media cassette  2  contacts with a pushing out member  10  of the image forming apparatus body  1 , when the media cassette  2  is on a way to a position where the media cassette  2  is attached to the image forming apparatus body  1  (a first state of combination). 
     In the first state of combination, a first ground conducting route comprising the recording media  20 , the loading plate  3 , the conducting member  4  and the pushing out member  10 ; is formed. A static electricity already charged before the attachment, on a recording medium or in the media cassette including the loading plate  3 , is discharged through the first ground conducting route to a grounding point  100 . 
       FIG. 6  is an explanatory diagram showing a chief elements of a structure (a second state of combination) of Embodiment 1. 
       FIG. 6  shows a state that a plate holding portion  6  of the media cassette  2  contacts with a release portion  11  of the image forming apparatus body  1 , when the media cassette  2  is still on a way near to a position where the media cassette  2  is attached to the image forming apparatus body  1  (a second state of combination). 
     In the second state of combination, the recording media  20  does not contact with a media supplying roller  9  yet, because a force of a pushing up member  5  is contained by engaging a plate holding portion  6  with an L shaped crook portion  7  formed on the backside of the loading plate  3 . 
       FIG. 7  is an explanatory diagram showing a chief elements of a structure (a state of a complete attachment) of Embodiment 1. 
       FIG. 7  shows a state that the media cassette  2  containing the recording media  20  is completely attached to the image forming apparatus body  1 . In this state, the plate holding portion  6  of the media cassette  2  is pushed by the release portion  11  of the image forming apparatus body  1 . Then, engagement of the plate holding portion  6  with the L shaped crook portion  7 , is released. When the engagement is released, the recording media  20  piled and loaded on the loading plate  3 , is pushed by a pushing up member  5  up to the media supplying roller  9 . As a result, a second ground conducting route comprising the recording media  20 , the media supplying roller  9 , the image forming apparatus body  1  and a grounding point  100 ; is formed. Here, the media supplying roller  9  is made up of a material such as a rubber, in which fragments of electron-conductive matter such as carbon or fila are scattered. This media supplying roller  9  contacts with a conductive contacting portion formed as prolonged from a prescribed portion of the image forming apparatus body  1 . And, the conductive contacting portion is connected to a grounding point  100  through a conductive portion of the image forming apparatus body  1 . Then, a static electricity generated in a printing operation by a friction between the recording media  20  and the media supplying roller  9 , between the recording media  20  and the separating rubber  12 , or between the recording media  20  themselves; and charged on a recording medium; is discharged through the second ground conducting route including the media supplying roller  9 , to a grounding point  100 . 
     As described above, a first ground conducting route is formed, when the media cassette  2  is on a way to a position where the media cassette  2  is attached to the image forming apparatus body  1 . Then, a static electricity already charged on a recording medium, is discharged through the first ground conducting route. And, a second ground conducting route is formed, when the media cassette  2  containing the recording media  20  is completely attached to the image forming apparatus body  1 . Then, a static electricity generated in a printing operation and charged on a recording medium existing at top of the pile of recording media  20 , is discharged through the media supplying roller  9  included in the second ground conducting route. Therefore, every static electricity charged on the media cassette  2 , is completely removed. And, obtained is an effect of eliminating inconveniences such as drop of graphical quality, malfunction of the apparatus, or electric shocks to operators; which are caused by a static electricity flowing in unexpected routes as a noise of electric current. 
     In the description mentioned above, a first ground conducting route comprises the recording media  20 , the loading plate  3 , the conducting member  4  and the pushing out member  10  leading to a grounding point  100 . However, the present invention is not limited to this example. That is, a static electricity to be discharged, is not limited to a static electricity charged on the recording media  20  or on the loading plate  3 . But, a static electricity charged on every element in the media cassette  2 , is a subject of the present invention. Therefore, a first ground conducting route can comprise all the conducting route that that is grounded through the pushing out member  10 , when the media cassette  2  is on a way to a position where the media cassette  2  is attached to the image forming apparatus body  1 . For example, a first ground conducting route can comprise the pushing up member  5  or the plate holding portion  6 , and the loading plate  3 , the conducting member  4  and the pushing out member  10  leading to a grounding point  100 . 
     Moreover, in the description mentioned above, a first ground conducting route is formed, when the media cassette  2  is on a way to a position where the media cassette  2  is attached to the image forming apparatus body  1 . However, the present invention does not limit a position of forming a first ground conducting route. That is, a first ground conducting route is continuously formed after the media cassette  2  is completely attached to the image forming apparatus body  1 . And, a static electricity generated in a printing operation and charged on a recording medium existing at top of the pile of recording media  20 , is discharged not only through the second ground conducting route but also through the first ground conducting route. 
     Embodiment 2 
     Configuration 
       FIG. 8  is an explanatory diagram showing a chief elements of a structure (before attaching) of Embodiment 2. 
       FIG. 8  shows a diagram of an image showing a positional relation of chief component parts only, seeing inside of an apparatus through a side wall of the apparatus&#39; body, so as to refer to explain a structure, a function and an operation of Embodiment 2. 
     As shown in  FIG. 8 , chief component parts of Embodiment 2 are an image forming apparatus body  51  and a media cassette  52 . The image forming apparatus body  51  comprises a media supplying roller  9 , a release portion  11  and a conveyance path  15 . The media cassette  52  (media supplying unit) comprises a loading plate  3 , a pushing up member  55 , a plate holding portion  6 , an L shaped crook portion  7 , an outer frame  58 , a separating rubber  12 , a coil spring  13 , a loading plate fulcrum  14  and a projecting portion  54 . 
     Chief component parts shown in  FIG. 8 , will be described in detail, referring to  FIG. 9 . The component parts in Embodiment 2 same as Embodiment 1, are designated with the same number as Embodiment 1. 
       FIG. 9  is a slant viewed diagram showing a media cassette and its attaching portion of Embodiment 2. 
       FIG. 9  shows a slant view of a media cassette and a slant view of a portion of an image forming apparatus body where the media cassette is attached. 
     A loading plate  3  is provided in the media cassette  52 . And, a pile of recording media (not shown in  FIG. 9 ) are loaded on the loading plate  3 . Then, a pair of side guides  44  hold the recording media  20  (shown in  FIG. 8 ) at longitudinal sides of them, and a tail guide  46  holds a lateral side of them, so as not to scatter in the media cassette  52 . 
     Thus, the recording media (not shown in  FIG. 9 ) held in the media cassette  52  and loaded on the loading plate  3 , are pressed by a pushing up member  55  to the media supplying roller  9  provided in the image forming apparatus body  51 , after the media cassette  52  is attached to the image forming apparatus body  51 . The loading plate  3  is supported by a loading plate fulcrum  45 , so as to rotate up and down around the loading plate fulcrum  45  formed at a prescribed portion of an outer frame  58 . The outer frame  58  is formed by a mold with resin. 
       FIG. 10  is a slant viewed diagram showing a loading plate of Embodiment 2. 
       FIG. 10  shows a slanted view of a backside of the loading plate  3  which is taken apart from the image forming apparatus body  51 . 
     As shown in  FIG. 10 , a loading plate  3  with a pile of recording media  20  is pressed to a media supplying roller  9  by a pushing up member  55  comprising a coil spring. A projecting member  54  is formed at an end of the pushing up member  55 . The projecting member  54  contacts with a metal plate  56  shown in  FIG. 9  provided on an inner base of the outer frame  58 . Thus, a static electricity charged on the recording media flows to the projecting portion  54 . 
     Moreover, a release frame  16  is made for containing a force of a pushing up member  55  by engaging a plate holding portion  6  with an L shaped crook portion  7  formed on the backside of the loading plate  3 , when the media cassette  52  is not attached to the image forming apparatus body  51 . Here, the release frame  16  with the plate holding portion  6  is provided at a prescribed portion of an outer frame (shown in  FIG. 9 ). When the media cassette  52  is attached to the image forming apparatus body  51 , a release portion  11  formed on an inner base of the image forming apparatus body  51  (shown in  FIG. 8 ) releases the engagement between the plate holding portion  6  and the L shaped crook portion  7 , with pressing a coil spring  13 . 
     Returning to  FIG. 8 , a function and an operation of Embodiment 2 will be described. 
     As shown in  FIG. 8 , the recording media  20  are loaded on the loading plate  3  piling up on it. The recording media  20  are held by a pair of side guides  44  ( FIG. 9 ) at longitudinal sides. And, they are held by a tail guide  46  at a lateral side. Thus, they do not scatter in the media cassette  52 . In  FIG. 8 , a force of a pushing up member  55  is contained by engaging a plate holding portion  6  with an L shaped crook portion  7  formed on the backside of the loading plate  3 , as the media cassette  52  is not attached to the image forming apparatus body  51 . 
     A portion of the recording media  20  contacts with the metal plate  56 . 
       FIG. 11  is an explanatory diagram showing a chief elements of a structure (a first state of combination) of Embodiment 2. 
       FIG. 11  shows a state that a projecting portion  54  of the media cassette  52  contacts with a release portion  11  of the image forming apparatus body  51 , when the media cassette  52  is on a way to a position where the media cassette  52  is attached to the image forming apparatus body  51  (a first state of combination). 
     In the first state of combination, a first ground conducting route comprising the recording media  20 , the loading plate  3 , the metal plate  56  (shown in  FIG. 9 ), the projecting portion  54  and the release portion  11 ; is formed. A static electricity already charged before the attachment, on a recording medium or in the media cassette  52  including the loading plate  3 , is discharged through the first ground conducting route to a grounding point  100 . 
       FIG. 12  is an explanatory diagram showing a chief elements of a structure (a second state of combination) of Embodiment 1. 
       FIG. 12  shows a state that a plate holding portion  6  of the media cassette  52  contacts with a release portion  11  of the image forming apparatus body  51 , when the media cassette  52  is still on a way near to a position where the media cassette  52  is attached to the image forming apparatus body  51  (a second state of combination). 
     In the second state of combination, the recording media  20  does not contact with a media supplying roller  9  yet, because a force of a pushing up member  55  is contained by engaging a plate holding portion  6  with an L shaped crook portion  7  formed on the backside of the loading plate  3 . 
       FIG. 13  is an explanatory diagram showing a chief elements of a structure (a state of a complete attachment) of Embodiment 2. 
       FIG. 13  shows a state that the media cassette  2  containing the recording media  20  is completely attached to the image forming apparatus body  51 . In this state, the plate holding portion  6  of the media cassette  52  is pushed by the release portion  11  of the image forming apparatus body  51 . Then, engagement of the plate holding portion  6  with the L shaped crook portion  7 , is released. When the engagement is released, the recording media  20  piled and loaded on the loading plate  3 , is pushed by a pushing up member  55  up to the media supplying roller  9 . As a result, a second ground conducting route comprising the recording media  20 , the media supplying roller  9 , the image forming apparatus body  51  and a grounding point  100 ; is formed. Then, a static electricity generated in a printing operation by a friction between the recording media  20  and the media supplying roller  9 , between the recording media  20  and the separating rubber  12 , or between the recording media  20  themselves; and charged on a recording medium; is discharged through the second ground conducting route including the media supplying roller  9 , to a grounding point  100 . 
     As described above, Embodiment 2 obtains an effect that the number of component parts can be decreased in addition to the same effect as Embodiment 1, because a metal plate is provided on an inner base of the media cassette in Embodiment 2, instead of a conducting plate  4  in Embodiment 1. 
     Embodiment 3 
     Configuration 
       FIG. 14  is an explanatory diagram showing a chief elements of a structure (before attaching) of Embodiment 3. 
       FIG. 14  shows a diagram of an image showing a positional relation of chief component parts only, seeing inside of an apparatus through a side wall of the apparatus&#39; body, so as to refer to explain a structure, a function and an operation of Embodiment 3. 
     As shown in  FIG. 14 , chief component parts of Embodiment 3 are an image forming apparatus body  61  and a media cassette  62 . The image forming apparatus body  61  comprises a media supplying roller  9 , a conveyance path  15 , a pulling up section  68  and a guide plate  69 . The pulling up section  68  comprises an arm plate  70 , an arm spring  71 , an arm frame  72  and a fulcrum portion  73 . The media cassette  62  comprises a loading plate  63 , an outer frame  65 , a separating rubber  12 , a loading plate fulcrum  45 , a catching portion  66  and a conducting plate  67 . 
     Chief component parts shown in  FIG. 14 , will be described in detail, referring to  FIG. 15 . The component parts in Embodiment 3 same as Embodiment 1, are designated with the same number as Embodiment 1. 
       FIG. 15  is a slant viewed diagram showing a media cassette and its attaching portion of Embodiment 3. 
       FIG. 15  shows a slant view of a media cassette and a slant view of a portion of an image forming apparatus body where the media cassette is attached. 
     A loading plate  63  is provided in the media cassette  62 . And, a pile of recording media (not shown in  FIG. 15 ) are loaded on the loading plate  63 . Then, a pair of side guides  44  hold the recording media  20  (shown in  FIG. 14 ) at longitudinal sides of them, and a tail guide  46  holds a lateral side of them, so as not to scatter in the media cassette  62 . 
     Thus, the recording media (not shown in  FIG. 15 ) held in the media cassette  62  and loaded on the loading plate  63 , are pressed by a pulling up section  68  of the image forming apparatus body  61 , to the media supplying roller  9  provided in the image forming apparatus body  61 , after the media cassette  62  is attached to the image forming apparatus body  61 . The pulling up section  68  is provided at each of left and right side of the image forming apparatus body  61 . The loading plate  63  is supported by a loading plate fulcrum  45 , so as to rotate up and down around the loading plate fulcrum  45  formed at a prescribed portion of an outer frame  65 . The outer frame  65  is formed by a mold with resin. 
       FIG. 16  is a slant viewed diagram showing a loading plate of Embodiment 3. 
       FIG. 16  shows a slanted view of a backside of the loading plate  63  which is taken apart from the image forming apparatus body  61 . 
     As shown in  FIG. 16 , a loading plate  63  comprises an arm plate  70 , an arm spring  71  and an arm frame  72 . And, the loading plate  63  with a pile of recording media  20  is pressed to a media supplying roller  9  by a pulling up section  68  of the image forming apparatus body  61 . In the pulling up section  68 , an arm frame  72  is pushed by a catching portion  66  formed on both side walls of the media cassette  62  (c.f.  FIG. 14 ). Then, an arm spring  71  is pulled, so as to rotate an arm plate  70  around a fulcrum portion  73 . 
     A conducting plate  67  comprising a conducting material of metal prolonged under the loading plate  63  in a direction of attaching the media cassette  62 , is provided in the media cassette  62 . An end of the conducting plate  67  touches a base of the loading plate  63  loading the recording media  20  (c.f.  FIG. 14 ). The other end of the conducting plate  67  prolonged upward of the media cassette  62 , touches a guide plate  69 . Then, a static electricity charged on the recording media  20  flows to a guide plate  69  provided at a prescribed portion of the image forming apparatus body  61 . The guide plate  69  is made of a metal plate. 
     Returning to  FIG. 14 , a function and an operation of Embodiment 3 will be described. 
     As shown in  FIG. 14 , the recording media  20  are loaded on the loading plate  63  piling up on it. The recording media  20  are held by a pair of side guides  44  ( FIG. 15 ) at longitudinal sides. And, they are held by a tail guide  46  at a lateral side. Thus, they do not scatter in the media cassette  62 . In  FIG. 14 , a force of a pulling up section  68  does not operate on the loading plate  63 , as the media cassette  62  is not attached to the image forming apparatus body  61 . 
       FIG. 17  is an explanatory diagram showing a chief elements of a structure (a first state of combination) of Embodiment 3. 
       FIG. 17  shows a state that a catching portion  66  formed on both side walls of the media cassette  62  contacts with an arm frame  72  of the pulling up section  68  of the image forming apparatus body  61 , when the media cassette  62  is on a way to a position where the media cassette  62  is attached to the image forming apparatus body  61  (a first state of combination). 
     In the first state of combination, a first ground conducting route comprising the recording media  20 , the loading plate  63 , the conducting plate  67  and the guide plate  69 ; is formed. A static electricity already charged before the attachment, on a recording medium or in the media cassette  62  including the loading plate  63 , is discharged through the first ground conducting route to a grounding point  100 . 
       FIG. 18  is an explanatory diagram showing a chief elements of a structure (a second state of combination) of Embodiment 2. 
       FIG. 18  shows a state that a catching portion  66  formed on both side walls of the media cassette  62  pushes an arm frame  72  of the pulling up section  68  of the image forming apparatus body  61 , when the media cassette  62  is still on a way near to a position where the media cassette  62  is attached to the image forming apparatus body  61 . As a result, in the pulling up section  68 , an arm spring  71  is pulled, so as to begin rotating an arm plate  70  around a fulcrum portion  73  (a second state of combination). 
     In the second state of combination, the recording media  20  does not contact with a media supplying roller  9  yet. 
       FIG. 19  is an explanatory diagram showing a chief elements of a structure (a state of a complete attachment) of Embodiment 3. 
       FIG. 19  shows a state that the media cassette  62  containing the recording media  20  is completely attached to the image forming apparatus body  61 . In this state, in the pulling up section  68 , an arm spring  71  is pulled, so as to rotate an arm plate  70  around a fulcrum portion  73 . As a result, the recording media  20  piled and loaded on the loading plate  63 , is pulled by the pulling up section  68  up to the media supplying roller  9 . And, a second ground conducting route comprising the recording media  20 , the media supplying roller  9 , the image forming apparatus body  61  and a grounding point  100 ; is formed. Then, a static electricity generated in a printing operation by a friction between the recording media  20  and the media supplying roller  9 , between the recording media  20  and the separating rubber  12 , or between the recording media  20  themselves; and charged on a recording medium; is discharged through the second ground conducting route including the media supplying roller  9 , to a grounding point  100 . 
     As described above, Embodiment 3 obtains an effect that the number of component parts can be decreased in addition to the same effect as Embodiment 1, because a pulling up section is provided at an image forming apparatus body  61 , and a plate holding portion  6 , an L shaped crook portion  7 , a coil spring  13  and a release frame  16  are omitted at a media cassette  62  in Embodiment 3. 
     Embodiment 4 
     Configuration 
       FIG. 20  is an explanatory diagram showing a chief elements of a structure (before attaching) of Embodiment 4. 
       FIG. 20  shows a diagram of an image showing a positional relation of chief component parts only, seeing inside of an apparatus through a side wall of the apparatus&#39; body, so as to refer to explain a structure, a function and an operation of Embodiment 4. 
     As shown in  FIG. 20 , chief component parts of Embodiment 4 are an image forming apparatus body  81  and a media cassette  82 . The image forming apparatus body  81  comprises a media supplying roller  9 , a conveyance path  15  and a pulling up section  68 . The pulling up section  68  comprises an arm plate  70 , an arm spring  71 , an arm frame  72  and a fulcrum portion  73 . The media cassette  62  comprises a loading plate  63 , an outer frame  65 , a separating rubber  12 , a loading plate fulcrum  45 , a catching portion  66  and a conducting plate  67 . 
     Chief component parts shown in  FIG. 20 , will be described in detail, referring to  FIG. 21 . The component parts in Embodiment 4 same as Embodiment 1 to 3, are designated with the same number as Embodiment 1 to 3. 
       FIG. 21  is a slant viewed diagram showing a media cassette and its attaching portion of Embodiment 4. 
       FIG. 21  shows a slant view of a media cassette and a slant view of a portion of an image forming apparatus body where the media cassette is attached. 
     A loading plate  63  is provided in the media cassette  82 . And, a pile of recording media (not shown in  FIG. 21 ) are loaded on the loading plate  63 . Then, a pair of side guides  44  hold the recording media  20  (shown in  FIG. 20 ) at longitudinal sides of them, and a tail guide  46  holds a lateral side of them, so as not to scatter in the media cassette  82 . 
     Thus, the recording media (not shown in  FIG. 21 ) held in the media cassette  82  and loaded on the loading plate  63 , are pressed by a pulling up section  68  of the image forming apparatus body  61 , to the media supplying roller  9  provided in the image forming apparatus body  61 , after the media cassette  62  is attached to the image forming apparatus body  61 . The loading plate  63  is supported by a loading plate fulcrum  45 , so as to rotate up and down around the loading plate fulcrum  45  formed at a prescribed portion of an outer frame  65 . The outer frame  65  is formed by a mold with resin. 
       FIG. 22  is a slant viewed diagram showing a loading plate of Embodiment 4. 
       FIG. 22  shows a slanted view of a backside of the loading plate  63  which is taken apart from the image forming apparatus body  81 . 
     As shown in  FIG. 22 , a loading plate  63  comprises an arm plate  70 , an arm spring  71  and an arm frame  72 . And, the loading plate  63  with a pile of recording media  20  is pressed to a media supplying roller  9  by a pulling up section  68  of the image forming apparatus body  61 . In the pulling up section  68 , an arm frame  72  is pushed by a catching portion  66  formed on both side walls of the media cassette  62  (c.f.  FIG. 14 ). Then, an arm spring  71  is pulled, so as to rotate an arm plate  70  around a fulcrum portion  73 . The fulcrum portion  73  of the pulling up section  68  is connected to a grounding point  100 . 
     Returning to  FIG. 20 , a function and an operation of Embodiment 4 will be described. 
     As shown in  FIG. 20 , the recording media  20  are loaded on the loading plate  63  piling up on it. The recording media  20  are held by a pair of side guides  44  ( FIG. 21 ) at longitudinal sides. 
     And, they are held by a tail guide  46  at a lateral side. Thus, they do not scatter in the media cassette  82 . In  FIG. 20 , a force of a pulling up section  68  does not operate on the loading plate  63 , as the media cassette  62  is not attached to the image forming apparatus body  61 . 
       FIG. 23  is an explanatory diagram showing a chief elements of a structure (a first state of combination) of Embodiment 4. 
       FIG. 23  shows a state that a catching portion  66  formed on both side walls of the media cassette  82  contacts with an arm frame  72  of the pulling up section  68  of the image forming apparatus body  81 , when the media cassette  82  is on a way to a position where the media cassette  82  is attached to the image forming apparatus body  81  (a first state of combination). 
     In the first state of combination, a first ground conducting route comprising the recording media  20 , the loading plate  63  and the fulcrum portion  73 ; is formed. A static electricity already charged before the attachment, on a recording medium or in the media cassette  82  including the loading plate  63 , is discharged through the first ground conducting route to a grounding point  100 . 
       FIG. 24  is an explanatory diagram showing a chief elements of a structure (a second state of combination) of Embodiment 4. 
       FIG. 24  shows a state that a catching portion  66  formed on both side walls of the media cassette  62  pushes an arm frame  72  of the pulling up section  68  of the image forming apparatus body  81 , when the media cassette  82  is still on a way near to a position where the media cassette  82  is attached to the image forming apparatus body  81 . As a result, in the pulling up section  68 , an arm spring  71  is pulled, so as to begin rotating an arm plate  70  around a fulcrum portion  73  (a second state of combination). 
     In the second state of combination, the recording media  20  does not contact with a media supplying roller  9  yet. 
       FIG. 25  is an explanatory diagram showing a chief elements of a structure (a state of a complete attachment) of Embodiment 4. 
       FIG. 25  shows a state that the media cassette  82  containing the recording media  20  is completely attached to the image forming apparatus body  81 . In this state, in the pulling up section  68 , an arm spring  71  is pulled, so as to rotate an arm plate  70  around a fulcrum portion  73 . As a result, the recording media  20  piled and loaded on the loading plate  63 , is pulled by the pulling up section  68  up to the media supplying roller  9 . And, a second ground conducting route comprising the recording media  20 , the media supplying roller  9 , the image forming apparatus body  81  and a grounding point  100 ; is formed. Then, a static electricity generated in a printing operation by a friction between the recording media  20  and the media supplying roller  9 , between the recording media  20  and the separating rubber  12 , or between the recording media  20  themselves; and charged on a recording medium; is discharged through the second ground conducting route including the media supplying roller  9 , to a grounding point  100 . 
     As described above, Embodiment 4 obtains an effect that the number of component parts can be further decreased in addition to the same effect as Embodiment 3, because a fulcrum portion  73  of a pulling up section  68  comprises a first ground conducting route in Embodiment 4. 
     Incidentally, in the above Embodiments, an image forming apparatus body attached with only one media cassette was described. However, the present invention is not limited to this example. That is, the present invention can be applied to an image forming apparatus body attached with plural media cassettes. 
     It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.