Patent Publication Number: US-9885999-B2

Title: Image forming apparatus including detecting device detecting opening/closing state of cover

Description:
INCORPORATION BY REFERENCE 
     This application is based on and claims the benefit of priority from Japanese Patent application No. 2015-254306 filed on Dec. 25, 2015, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     The present disclosure relates to an image forming apparatus which includes an opening/closing detecting device which detects an opening/closing state of a cover member. 
     An image forming apparatus is configured such that a toner container storage part or a sheet conveying part can be opened and closed by a cover member in order to replace the toner container or to remove a jammed sheet. When the cover member is opened, a user may touch a rotating body, such as a gear or a motor, or an electrical conductive member to supply electrical power to a driving member and an image forming unit may be exposed. Then, the image forming apparatus is generally provided with an interlock switch which interrupts the power supply when the cover member is opened. 
     The interlock switch is generally activated by the opening and closing of the cover member. In some cases, a link member is interposed between the interlock switch and the cover member. 
     However, because the cover member has a large size and also a large variation in dimension precision and assembling precision, the interlock switch may not be accurately activated by the opening and closing of the cover member. In addition, if a distance between the closed cover member and the interlock switch is smaller than a predetermined distance, the cover member is excessively pressed toward the interlock switch and then the interlock switch may be damaged by the cover member. 
     Furthermore, when the link member is interposed, it is necessary to prepare a dedicated link member. This may increase cost. In addition, in order to absorb the variation in dimension precision and assembling precision of the cover member, the interlock switch may be provided so as to be movable. However, in this case, since it is difficult to hold the interlock switch stably and also it is necessary to lengthen a wire connected to the interlock switch, a structure may be complicated and an erroneous detecting may easily occur. 
     SUMMARY 
     In accordance with an embodiment of the present disclosure, an image forming apparatus includes a cover member, an opening/closing detecting device and an elastic member. The cover member is supported so as to open and close an opening formed in an apparatus main body. The opening/closing detecting device is configured to be switched into OFF state to detect that the cover member is in opening state where the opening is opened and into ON state to detect that the cover member is in closing state where the opening is closed. The elastic member is interposed between the opening/closing detecting device and the cover member. The elastic member is configured to be deformed when the cover member closes the opening and then to switch the opening/closing detecting device from the OFF state into the ON state. 
     The above and other objects, features, and advantages of the present disclosure will become more apparent from the following description when taken in conjunction with the accompanying drawings in which a preferred embodiment of the present disclosure is shown by way of illustrative example. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing a color printer, viewed from a rear side, according to one embodiment of the present disclosure. 
         FIG. 2  is a side view schematically showing an entire structure of the color printer according to one embodiment of the present disclosure. 
         FIG. 3  is a perspective view showing an apparatus main body with a rear cover opened, viewed from the rear side, in the color printer according to one embodiment of the present disclosure. 
         FIG. 4  is a perspective view showing the apparatus main body with a left side cover removed, viewed from the rear side, in the color printer according to one embodiment of the present disclosure. 
         FIG. 5  is a perspective view showing an interlock switch in OFF state and its peripheral portions, in the color printer according to one embodiment of the present disclosure. 
         FIG. 6  is a front view showing the interlock switch in the OFF state and the peripheral portions, in the color printer according to one embodiment of the present disclosure. 
         FIG. 7  is a perspective view showing the interlock switch in ON state and the peripheral portions, in the color printer according to one embodiment of the present disclosure. 
         FIG. 8  is a front view showing the interlock switch in the ON state and the peripheral portions, in the color printer according to one embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, with reference to figures, an image forming apparatus according to an embodiment of the present disclosure will be described. 
     First, an entire structure of a color printer as the image forming apparatus will be described with reference to  FIG. 1  and  FIG. 2 .  FIG. 1  is a perspective view showing the color printer viewed from a rear side and  FIG. 2  is a view schematically showing an internal structure of the color printer. In the following description, front and rear directions shown in  FIG. 1  indicate front and rear directions of the color printer  1  and left and right directions are based on a direction in which the color printer  1  is viewed from the front side. 
     A color printer  1  includes an apparatus main body  2  in a rectangular parallelepiped shape. An upper face, a left side face, a right side face, a front face and a rear face of the apparatus main body  2  are respectively covered with an upper cover  4 , a left side cover  5 , a right side cover  6 , a front cover  7  and a rear cover  8 . As shown in  FIG. 2 , the upper cover  4  is formed with a switchback part  11  and a sheet ejecting port  12  which are arranged in the vertical direction. The upper cover  4  is also formed with an ejected sheet tray  13  below the sheet ejecting port  12 . The rear cover  8  that is a cover member is supported to an opening  2   a  formed on the rear face of the apparatus main body  2  so as to be rotatable around its lower end to open or close the opening  2   a . Inside the opening  2   a , a conveying unit  15  is supported so as to be rotatable around its lower end. 
     In a lower part of an inside of the apparatus main body  2 , a sheet feeding cassette  17  in which sheets S are stored and a sheet feeding device  18  which feeds the sheet S from the sheet feeding cassette  17  are provided. Above the sheet feeding cassette  17 , an exposure device  19  is provided. Above the exposure device  19 , an intermediate transferring belt  21  and an image forming unit  22  are provided. The intermediate transferring belt  21  is supported so as to circulate. The image forming unit  22  forms a toner image on the intermediate transferring belt  21  in an electrographic manner by using toner of four colors. To the image forming unit  22 , toner containers  23  containing toner of each color are connected. 
     On the rear side of the intermediate transferring belt  21 , a second transferring roller  25  is rotatably supported by the conveying unit  15 . Between the intermediate transferring belt  21  and the second transferring roller  25 , a second transferring part  26  is formed. Above the second transferring part  26 , a fixing device  28  is provided, and above the fixing device  28 , a sheet ejecting device  29  is provided so as to face the sheet ejecting port  12 . 
     In the inside of the apparatus main body  2 , a main conveying path  31  and a duplex printing path  32  for the sheet S are formed. The main conveying path  31  is formed from the sheet feeding device  18  toward the sheet ejecting device  29  through the second transferring part  26  and the fixing device  28  along in inner face of the conveying unit  15 . The duplex printing path  32  is branched from the main conveying path  31  at a downstream side portion from the fixing device  28  in the conveying direction into the switchback part  11  and then joined to the main conveying path  31  at a downstream side portion from the sheet feeding device  18  along a space between the conveying unit  15  and the rear cover  8 . 
     Next, the operation of forming an image by the color printer  1  having such a configuration will be described. When the exposure device  19  exposes the image forming unit  22  based on an image date, the image forming unit  22  forms a toner image on the intermediate transferring belt  21 . On the other hand, the sheet S fed from the sheet feeding cassette  17  by the sheet feeding device  18  is conveyed along the main conveying path  31  into the second transferring part  26  in a suitable timing with the above image forming operation. At the second transferring part  26 , the toner image on the intermediate transferring belt  21  is second-transferred on the sheet. The sheet on which the toner image is transferred is conveyed on a downstream side along the main conveying path  31  to the fixing device  28 . Then, the toner image is fixed on the sheet S in the fixing device  28 . The sheet S with the fixed toner image is ejected from the sheet ejecting device  29  to the ejected sheet tray  13 . 
     In the duplex printing, the sheet S with the image formed on one side is conveyed from the main conveying path  31  into the duplex printing path  32 , then along the duplex printing path  32  and then along the main conveying path  31  again to form an image on the other side in the same way. 
     When the sheet S jammed on the duplex printing path  32  is removed, the rear cover  8  is turned around its lower end to open the duplex printing path  32 . On the duplex printing path  32 , conveying rollers and the others (not shown) are provided. When the duplex printing path  32  is thus opened, conductive members (not shown) which supply power to the conveying rollers and the others may be exposed. Then, the apparatus main body  2  is provided with an interlock switch  40  as an opening/closing detecting device that detects an opening/closing state of the rear cover  8  and interrupts the power supply to the conductive members when the rear cover  8  is in the opening state. 
     Next, the rear cover  8  and the interlock switch  40  will be described with reference to  FIG. 3  to  FIG. 8 .  FIG. 3  is a perspective view showing the color printer with the rear cover opened, viewed from the rear side and  FIG. 4  is a perspective view showing the color printer with the left side cover removed, viewed from the rear side.  FIG. 5  to  FIG. 8  are views showing the interlock switch and its peripheral portions.  FIG. 5  and  FIG. 6  are respectively a perspective view and a front view showing the rear cover in the opening state and  FIG. 7  and  FIG. 8  are respectively a perspective view and a front view showing the rear cover in the closing state. 
     As shown in  FIG. 3 , the rear cover  8  is formed with a projection  42 . The projection  42  protrudes forward from a center portion in the vertical direction of a left side edge portion of the inner face of the rear cover  8 . A tip end face of the projection  42  curves in an arc shape in a side view. In the tip face of the projection  42 , a vertical groove  42   a  is formed (refer to  FIG. 7 ). The left side cover  5  is formed with a passing port  43  through which the projection  42  is passed when the rear cover  8  is closed. 
     As shown in  FIG. 4 , inside of the left side cover  5 , a base member  45  is provided. Along an outer periphery of the base member  45 , a side edge portion bent outward is formed. In a recess surrounded by the side edge portion, a main control substrate  47 , a power supply substrate  48  and a shield member (not shown) are supported on the base member  45 . The main control substrate  47  controls the image forming unit and the others. The power supply substrate  48  is electrically connected to an exterior power source and supplies the power to the main control substrate  47 . The shield member covers outsides of the main control substrate  47  and the power supply substrate  48  to shield them electrically. 
     In the rear side edge portion  45   a  bent outward along the rear edge of the base member  45 , an inner passing port  51  is formed so as to align with the passing port  43  formed in the left side cover  5 . Around the inner passing port  51 , a guide tube  52  protrudes rearward. 
     As shown in  FIG. 5  and  FIG. 6 , the interlock switch  40  is supported on the base member  45  above the inner passing port  51  by hooks. The interlock switch  40  has a rectangular parallelepiped shaped main body part  55 , a switching part  56  protruding from a side face of the main body part  55  and an operating lever  57  which presses and releases the switching part  56 . The main body part  55  is supported on the base member  45  with the switching part  56  directed rearward so that the switching part  56  is pressed and released from the pressing in the front and rear directions. The switching part  56  is pushed into the main body part  55  by being pressed with predetermined load and is returned into an original posture by being released from the pressing. When the switching part  56  is pressed, the interlock switch  40  is switched into ON state to detect that the rear cover  8  is in the closing state. When the switching part  56  is released from the pressing to return into the original posture automatically, the interlock switch  40  is switched into OFF state to detect that the rear cover  8  is in the opening state and then to interrupt the power supply from the power supply substrate  48  to the conductive members via the main control substrate  47 . 
     The operating lever  57  is supported to the side face of the main body part  55  in a cantilever manner above the switching part  56 . In a normal posture, the operating lever  57  is suspended in a lower oblique direction beyond the main body part  55 . When being pressed, the operating lever  57  is turned in the counterclockwise direction in  FIG. 6  into a pressing position to press the switching part  56 . When being released from the pressing, the operating lever  57  is elastically returned into the normal posture (a releasing position) to release the switching part  56 . With the elastic retuning of the operating lever  57 , the switching part  56  is returned into the original posture. 
     On the base member  45 , a restricting part  59  in a plate shape is formed along the vertical direction below the interlock switch  40 . The restricting part  59  is configured to restrict the pressing of the operating lever  57  over the switching part  56 . 
     On the base member  45 , a boss  61  is formed inside of the inner passing port  51 . From a tip end of the boss  61 , a slip-off preventing piece  61   a  protrudes radially. Around the boss  61 , a torsion coil spring  70  is fitted. The torsion coil spring  70  is an elastic member interposed between the rear cover  8  and the interlock switch  40 . 
     The torsion coil spring  70  has a coil part  71 , a first arm part  72  and a second arm part  73 . The coil part  71  is formed by winding a wire in a spiral shape. The first arm part  72  is formed by extending the wire from one end of the coil part  71 . The second arm part  73  is formed by extending the wire from the other end of the coil part  71 . A tip portion of the first arm part  72  is wound spirally in the same winding direction as the coil part  71 . At a tip portion of the second arm part  73 , a bent portion  73   a  bent along a coil axis of the coil part  71  is formed. The first arm part  72  has a length longer than a length of the second arm part  73 . 
     The coil part  71  is supported by the boss  61  so as to be turnable with the slipping off from the boss  61  prevented by the slip-off preventing piece  61   a . The first arm part  72  is engaged with a lower edge of the inner passing port  51  formed in the rear side edge portion  45   a  of the base member  45 . Then, the torsion coil spring  70  is grounded into the base member  45 . The second arm part  73  directs in a rear upper direction and the bent portion  73   a  is separated rearward from the operating lever  57  of the interlock switch  40 . 
     In the color printer having the above configuration, a turning of the rear cover  8  will be described with reference to  FIG. 5  to  FIG. 8 . 
     When the rear cover  8  is turned into the opening state where the opening  2   a  is opened, as shown in  FIG. 5  and  FIG. 6 , in the torsion coil spring  70 , the first arm part  72  is engaged with the lower edge of the inner passing port  51  formed in the rear side edge portion  45   a  of the base member  45  and the second arm part  73  is separated rearward from the operating lever  57  of the interlock switch  40 . 
     When the rear cover  8  is turned into the closing state where the opening  2   a  is closed, the projection  42  formed on the inner face of the rear cover  8  passes the passing port  43  of the left side cover  5  and enters the inner passing port  51  through the guide tube  52  of the rear side edge portion  45   a  of the base member  45 . Then, when the groove  42   a  of the projection  42  abuts against the first arm part  72 , the coil part  71  of the torsion coil spring  70  is turned in the clockwise direction in  FIG. 5  and  FIG. 6  around the boss  61 . 
     Then, as shown in  FIG. 7  and  FIG. 8 , the second arm part  73  abuts against the operating lever  57  and presses the operating lever  57 . When pressed, the operating lever  57  presses the switching part  56  so that the interlock switch  40  is switched into the ON state. During the turning of the torsion coil spring  70 , since the curved tip portion of the first arm part  72  is slide along the groove  42   a  of the projection  42 , it becomes possible to turn the torsion coil spring  70  smoothly so as not to deflect horizontally. 
     In addition, if the rear cover  8  is further turned after the switching part  56  is pressed, the first arm part  72  is pressed by the projection  42  and approaches the second arm part  73 . In other words, the torsion coil spring  70  is elastically deformed such that the first arm part  72  and the second arm part  73  approach each other. Then, a turning distance of the rear cover  8 , that is, a turning distance of the projection  42  after the switching part  56  is pressed is absorbed by the elastic deformation of the torsion coil spring  70  so that the switching part  56  is not applied with large load through the operating lever  57 . In addition, when the rear cover  8  abuts against the left side cover  5 , the turning of the rear cover  8  is prevented so that the first arm part  72  may not be excessively pressed by the projection  42 . Furthermore, since the tuning of the operating lever  57  is restricted by the restricting part  59 , the interlock switch  40  can be protected more surely. 
     When the rear cover  8  is turned into the opening state where the opening  2   a  is opened, the projection  42  is separated from the first arm part  72  of the torsion coil spring  70  and then the operating lever  57  is elastically returned into the normal posture. Then, the switching part  56  is released from the pressing and the interlock switch  40  is switched into the OFF state. By the elastic returning of the operating lever  57 , the second arm part  73  is biased to turn the coil part  71  in the counterclockwise direction in  FIG. 7  and  FIG. 8  around the boss  61 . In addition, since the first arm part  72  has the length longer than the length of the second arm part  73 , the coil part  71  easily turns in a direction of the first arm part  72  by the weight of the first arm part  72 , that is, in the counterclockwise direction. Then, the first arm part  72  is automatically engaged with the lower edge of the inner passing port  51  (refer to  FIG. 5  and  FIG. 6 ). 
     As described above, in the color printer  1  according to the present disclosure, the torsion coil spring  70  makes it possible to activate the interlock switch  40  surely with the tuning of the rear cover  8  into the opening state and the closing state. Accordingly, the erroneous detecting of the interlock switch  40  can be prevented. In addition, a variation in turning distance of the projection  42  caused by the large variation in dimension precision of the rear cover  8  is absorbed by the elastic deformation of the torsion coil spring  70 . Accordingly, the interlock switch  40  may not be damaged by being applied with excessive load. 
     In a state where the rear cover  8  is turned into the opening state where the opening  2   a  is opened, the torsion coil spring  70  is automatically supported such that the first arm part  72  is engaged with the lower edge of the inner passing port  51  and the second arm part  73  is separated from the operating lever  57 . Under the state, when the rear cover  8  is turned into the closing state where the opening  2   a  is closed, the projection  42  abut against the first arm part  72  first. At this time, if a user who turns the rear cover  8  may be electrically charged, when the user brings his finger closer to the inner passing port  51 , the static charge of the user is grounded into the base member  45  through the first arm part  72  and the coil part  71 . Accordingly, the static charge is prevented from flowing into the interlock switch  40  so that the interlock switch  40  can be protected against the static charge. 
     In the embodiment, the torsion coil spring  70  is used as the elastic member; a plate spring or the like may be used. However, the torsion coil spring  70  is preferable because of simple structure and easy assembling. 
     The embodiment shows a case where the rear cover  8  is turned to open and close the opening  2   a  of the apparatus main body  2   a . However, the embodiment can be applied to a cover member which is slid to open and close the opening  2   a  of the apparatus main body  2   a.    
     The embodiment was described in a case of applying the configuration of the present disclosure to the color printer  1 . On the other hand, in another embodiment, the configuration of the disclosure may be applied to another image forming apparatus, such as a copying machine, a facsimile or a multifunction peripheral, except for the printer  1 . 
     While the preferable embodiment and its modified example of the image forming apparatus of the present disclosure have been described above and various technically preferable configurations have been illustrated, a technical range of the disclosure is not to be restricted by the description and illustration of the embodiment. Further, the components in the embodiment of the disclosure may be suitably replaced with other components, or variously combined with the other components. The claims are not restricted by the description of the embodiment of the disclosure as mentioned above.