Abstract:
A connection mechanism connecting a sheet feeding unit, supplying a paper to an image forming apparatus, with the image forming apparatus or other sheet feeding unit, the connection mechanism comprising: a connection member disposed on a frame of the sheet feeding unit and rotatably supported on the frame; and an engaging member disposed on the image forming apparatus or the frame of the other sheet feeding unit, wherein: the connection member is rotated between an engaging position where the connection member engages with the engagement member and a retracting position where the connection member disengages with the engaging member and retracts from the engaging position.

Description:
The present application claims priority on Japanese Patent Application No. 2008-158897, filed Jun. 18, 2008, the content of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a sheet feeding unit that can be connected in series to a main body of an image forming apparatus via a connection mechanism. The image forming apparatus includes a sheet feeding unit. Examples of the image forming apparatus include a copying machine, a printer, and a facsimile machine. 
     2. Description of the Related Art 
     According to a image forming apparatus that includes a sheet feeding unit that can be connected in series to the main body of the image forming apparatus, merely fixing the positions of the sheet feeding unit and the printer P, such as the main body of the image forming apparatus or other sheet feeding units, makes it difficult to maintain physical stability when the image forming devices receive an impact by, for example, being pushed or struck from the front, back, right, or left. As a result, the image forming apparatus might be damaged because the connection may be detached and the image forming apparatus may fall over. Consequently, it is necessary to restrict any detachment or separation between the paper feeding unit and the printer P by setting up a connection mechanism between the paper feeding unit and the printer P. 
     In order to attain a level of safety regarding such image forming devices, safety guidelines such as UL, CSA, and IEC are established for testing how the image forming apparatus is knocked down. 
     Japanese Unexamined Patent Application, First Publication No. H5-142871 (hereinafter referred to as Patent Document 1) discloses a mechanism for fixing and connecting a copying machine. According to this fixing and connecting mechanism, a connecting device used to fix positions is set up in a lower section of the main body of the copying machine. In addition, the fixing and connecting mechanism forms a positioning fixture that fixes and connects a positioning connecting tool to the printer P. Further, this fixing and connecting mechanism matches a screw hole formed on the above connecting tool and the above fixing tool. Thus, the fixing and connecting mechanism is structured to bind and fix the connecting tool and the fixing tool using bolts and the like. 
     However, the connection mechanism recited in Patent Document 1 is structured to screw objects together using bolts and the like. Thus, even though a desired level of physical stability is attained, tools are needed to connect or disconnect objects. As a result, it is burdensome to use the connection mechanism, and the connection mechanism cannot be operated easily. 
     Considering the problems described above, the present invention aims to provide a sheet feeding unit and an image forming apparatus including a connection mechanism that is physically stable, easy to operate, and can easily establish connection between the sheet feeding unit and the printer P. 
     SUMMARY OF THE INVENTION 
     In order to achieve the above object, the present invention employs the following. 
     Namely, a connection mechanism connecting a sheet feeding unit, supplying a paper to an image forming apparatus, with the image forming apparatus or other sheet feeding unit, the connection mechanism including: a connection member disposed on a frame of the sheet feeding unit and rotatably supported on the frame; and an engaging member disposed on the image forming apparatus or the frame of the other sheet feeding unit, wherein: the connection member is rotated between an engaging position where the connection member engages with the engagement member and a retracted position where the connection member disengages from the engaging member and retracts from the engaging position. 
     In addition, the connection member is disposed on an upper part of the frame of the sheet feeding unit; and the engaging unit is disposed on a lower part of the image forming apparatus or a lower part of the frame of the other sheet feeding unit. 
     In addition, the connection mechanism according to the aspect of the present invention may be configured as follows: when the connection member is located at the connecting position, a part of the connection member protrudes outside from an upper part of the frame, and when the connection member is located at the retracted position, the connection member is stored within the frame. 
     In addition, the connection mechanism according to the aspect of the present invention may be configured as follows: the connection member includes a click portion protruding in a direction of a rotation center thereof, and the engaging member includes an engaging portion protruding to and engaged with the click portion in the connecting position. 
     On the other hand, a sheet feeding unit supplies a paper in an image forming apparatus, the sheet feeding unit having a connection mechanism connecting the sheet feeding unit with the image forming apparatus or other sheet feeding unit, the sheet feeding unit comprising: a frame; and a connection mechanism including a connection member and an engaging member, the connection member disposed and rotatably supported on the frame, the engaging member disposed on the image forming apparatus or the frame of the other sheet feeding unit, wherein: the connection member is rotated between an engaging position where the connection member engages with the engagement member and a retracted position where the connection member disengages from the engaging member and retracts from the engaging position. 
     In addition, the sheet feeding unit according to the aspect of the present invention may be configured as follows: the frame is shaped approximately as a rectangle in planar view; a plurality of connection mechanisms are disposed along a short side of the frame; and a connection member of each of the above connection mechanisms is disposed so that an axis of the turning coincides approximately with the direction of the short side. 
     In addition, the sheet feeding unit according to the aspect of the present invention may be configured as follows: a plurality of the above connection mechanisms are included on both ends of the short side. 
     In addition, the sheet feeding unit according to the aspect of the present invention may be configured as follows: the connection member is located on a side of the frame that is lower in a weight distribution while the sheet feeding unit is connected to the image forming apparatus or the other sheet feeding unit. 
     In addition, the sheet feeding unit according to the aspect of the present invention may be configured as follows: the frame includes a cassette insertion slot for inserting a sheet feeding cassette therein; and the connection mechanism is located on an inner wall of the frame in a side opposite to a side where the cassette insertion slot is formed. 
     In addition, the sheet feeding unit according to the aspect of the present invention may be configured as follows: the connection member has a different color from the inner wall. 
     Based on the sheet feeding unit according to the aspect of the present invention described above, it is possible to provide a paper supplying unit and an image forming apparatus that are physically stable, easy to operate, and can be easily connected together. 
     On the other hand, an image forming apparatus includes the sheet feeding unit described above. 
     The above object as well as other objects of the present invention and the present invention&#39;s characteristics and advantages will become clearer from the appended figures and the detailed description below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing a printer according to an embodiment of the present invention. 
         FIG. 2  is a rough diagram showing a configuration of a printer according to the above embodiment of the present invention. 
         FIG. 3  is a perspective view of a sheet feeding unit showing a configuration of a connection mechanism according to the above embodiment of the present invention when a main body of an image forming apparatus is removed. 
         FIG. 4  is a cross sectional view in the X-X plane of  FIG. 3  showing a configuration of a connection mechanism according to the above embodiment of the present invention. 
         FIG. 5  is a perspective view showing a connection member according to the above embodiment of the present invention when the connection member is in a connecting position. 
         FIG. 6  is a perspective view showing a connection member according to the above embodiment of the present invention when the connection member is in a disconnected position. 
         FIG. 7  is a front view showing a connection member according to the above embodiment of the present invention when the connection member is in a connecting position. 
         FIG. 8  is a front view showing a connection member according to the above embodiment of the present invention when the connection member is in a disconnected position. 
         FIG. 9  is a perspective view showing a configuration of a back side of a connection member according to the above embodiment of the present invention. 
         FIG. 10  is a perspective view showing a configuration of a frontal side of a connection member according to the above embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An embodiment of a sheet feeding unit and an image forming apparatus according to the present invention is described with reference to the drawings. The description below concerns an aspect of the present invention being applied to a printer (an image forming apparatus). Each unit shown in the drawings is expanded or contracted, as necessary, so that each unit can be large enough to be visible. 
     First, a configuration of a printer P according to the present embodiment is described with reference to  FIGS. 1 and 2 . 
       FIG. 1  is a perspective view showing a printer P according to the present embodiment. 
       FIG. 2  is a rough diagram showing a configuration of a printer P according to the above embodiment. 
     As shown in  FIG. 1 , printer P includes a plurality of paper feeding units  100  that can be connected in series to the main body of the image forming apparatus  1 . The printer P according to the present embodiment is equipped with three paper feeding units  100  which are stacked on top of one another. The main body of the image forming apparatus  1  is placed on top of the three paper feeding units. The paper feeding unit  100  is configured as an optional unit so that the number of the paper feeding units can be increased to a desired amount. 
     As shown in  FIG. 2 , the main body of the image forming apparatus  1  includes an image forming section  2  which forms an image on a recording medium, a paper feeding cassette  3  which stores the recording medium, a secondary transfer section  4  which transfers the image formed by the image forming section  2  to the recording medium, a fixing unit  5  which fixes the copied image to the recording medium, a discharge tray  6  which stacks the recording mediums that are ejected after the fixing of the image was completed, and a conveying path  7  which conveys the recording medium from the paper feeding cassette  3  to the catch tray  6 . Further, the main body of the image forming apparatus  1  includes a manual tray  8  which can be pulled open and closed. Consequently, the main body of the image forming apparatus  1  is configured so that a carrying path from the manual tray  8  can be joined into the carrying path  7 . 
     The image forming section  2  includes an intermediate transfer belt  20 , a cleaning unit  21  which cleans the intermediate transfer belt  20 , and image forming units F (FY, FM, FC, and FB) which correspond respectively to colors yellow (Y), magenta (M), cyan (C), and black (BK). 
     The intermediate transfer belt  20  is wrapped around a driving roller  22  and a tension roller  23 . In addition, the intermediate transfer belt  20  runs clockwise in  FIG. 2 . 
     The cleaning unit  21  includes, for example, a cleaning roller and a cleaning blade, and the like. In addition, the cleaning unit  21  removes toners, and the like, which were left in the intermediate transfer belt  20 . 
     The image forming unit F includes a photoconductor  10 , a charging device  11 , an exposure device  12 , a development device  13 , and a primary transfer roller  14 . Further, the image forming unit F includes, for example, a cleaning device and a erase device, and the like (not diagramed). 
     The photoconductor  10  is formed as a cylinder. An electrostatic latent image and a toner image based on the electrostatic latent image are formed on a circumferential surface of the photoconductor  10 . The charging device  11  is located to face the photoconductor  10 . The charging device  11  charges the circumferential surface of the photoconductor  10 . The exposure device  12  scans a laser beam which is generated based on image data in a printable format on the circumferential surface of the photoconductor  10  in an electrically charged state. 
     The development device  13  develops the electrostatic latent image on the circumferential surface of the photoconductor  10  by supplying toner. The primary transfer roller  14  is located so that the primary transfer roller  14  faces the photoconductor  10 , with the intermediate transfer belt  20  located between the primary transfer roller  14  and the photoconductor  10 . In addition, the primary transfer roller  14  primarily transfers the image, developed on the photoconductor  10 , onto the intermediate transfer belt  20 . 
     The paper feeding cassette  3  can be pulled out from the main body of the image forming apparatus  1 . Furthermore, the paper feeding cassette  3  holds the recording medium. 
     The secondary copying unit  4  secondarily copies the image, formed on the intermediate transfer belt  20 , onto the recording medium. In addition, the secondary copying unit  4  includes a driving roller  22  which drives the intermediate transfer belt  20  and a secondary copying roller  41  which is placed facing the driving roller  22 , with the intermediate transfer belt  20  located between the driving roller  22  and the copying roller  41 . 
     The fixing unit  5  fixes images which were secondarily transferred onto the recording medium. In addition, the fixing unit  5  includes a heating roller  51  which fixes a toner by applying pressure and heat. 
     The conveying path  7  includes, for example, a pickup roller  71  placed on the paper feeding cassette  3 , the pickup roller  71  carrying a recording medium from the paper feeding cassette  3 , a paper feeding roller  72  which carries the recording medium, and an ejection roller  73  which ejects the recording medium onto the catch tray  6 . 
     The paper feeding unit  100  is an optional unit which can be detached from the main body of the image forming apparatus  1  configured as described above. This paper feeding unit  100  can be connected to the main body of the image forming apparatus  1  or another paper feeding unit  100  via a connection mechanism  110  (described later). 
     The paper feeding unit  100  is shaped substantially as a rectangular box in planar view (refer to  FIG. 3 ). The paper feeding unit  100  includes a frame  101  which is shaped like a box, a paper feeding cassette  103  which stacks recording mediums and can be inserted to and removed from the frame  101 , a feeding path  107  which connects the paper feeding cassette  103  and the carrying path  7  of the main body of the image forming apparatus  1 . The bottom surface (not diagramed) of the frame  101  is not closed by a bottom plate but opened. 
     The paper feeding unit  100  (frame  101 ) includes a cassette loading slot  102  which opens toward the front side. The paper feeding cassette  103  can be pulled out via the cassette loading slot  102 , and can be detached as well. 
     The unit feeding path  107  provided in the frame  101  includes, for example, a pickup roller  171  that feeds out a recording medium from the paper feeding cassette  103  and a paper feeding roller  172  which feeds the recording medium. 
     According to the printer P as configured above, the weight distribution deviates toward the front side (the side where the manual tray  8  is placed) where a number of devices and rollers and the like are placed as shown in  FIG. 2 . 
     Next, a configuration of the connection mechanism  110  is described with reference to  FIGS. 3 to 10 . 
     As shown in  FIG. 3 , the paper feeding unit  100  (frame  101 ) includes a connector  111  which electrically connects the paper feeding unit  100  with a connected object such as the image forming apparatus, printer P, or other paper feeding units, a positioning pin  112  which positions the connected object, which is placed on top of the paper feeding unit  100 , to a desired location, and a connection mechanism  110  which connects and disconnects the paper feeding unit  100  and the connected object. 
     The connector  111  and the positioning pin  112  are provided on a ceiling plate  101   a  which forms a ceiling of the front side of the frame  101  of the paper feeding unit  100 . The positioning pin  112  is placed respectively on both ends of the paper feeding unit  100  (frame  101 ) in the direction of the shorter side. One of the positioning pins  112  is placed near the connector  111 . 
     A plurality of the connection mechanisms  110  are located along a short side of the back side of the paper feeding unit  100  (frame  101 ). In other words, the connection mechanism  110  is located on the back side in which there is a lower weight distribution of the printer P supported by the paper feeding unit  100 . Further, two connection mechanisms  110  according to the present embodiment are placed on both ends of the short side. One connection mechanism  110  is placed on each end of the short side. 
     The connection mechanism  110  includes a connection member  120  and an engaging member  130 . As shown in  FIG. 4 , the connection member  120  is placed so that a basal portion  121 , which is located on an inner wall  100   a  of the paper feeding unit  100  (frame  101 ), can turn freely. Further, as shown in  FIG. 4 , the connection member  120  is placed so that the rotation axis  121   a  of the basal portion  121  is approximately along in the direction of a short side. The connection member  120  is configured so as to turn freely around the rotational axis  121   a  of the basal portion  121 . 
     According to a configuration of the present embodiment, the tip portion  122  can move freely between a connecting position (shown in a solid line in  FIG. 4 ) and a disconnected position (shown in a dotted line in  FIG. 4 ). A connection of the paper feeding unit  100  and the printer P is made at the connecting position. A disconnected position is 180 degrees rotated from the connecting position. Connection is disconnected at the disconnected position. 
     When the tip portion  122  is located at the disconnected position, the connection member  120  is put in the paper feeding unit  100  (frame  101 ) as shown in  FIGS. 6 and 8 . As a result, it is possible to prevent the connection member  120  from being a contributing factor to damage such as unexpected impact from the outside that occurs when the connection member is not used to connect devices, for example, the paper feeding unit  100  is packaged or transported. 
     Meanwhile, when the tip portion  122  is located at the connecting position, the connection member  120  is located in a perpendicular state such that the tip portion  122  protrudes above the paper feeding unit  100  (frame  101 ) as shown in  FIGS. 5 and 7 . At this time, the connection member  120  engages with the engaging member  130  which is located on the bottom part of the printer P shown in  FIG. 4 . 
     Regarding the back side  120 A of the connection member  120  shown in  FIG. 9 , three convex portions  124  are formed parallel to each other on the connection member  120 . Each of the three convex portions  124  is elongated in the width direction of the connection member  120 . Furthermore, one convex portion  124  is formed on the end of the tip portion  122  of the connection member  120 . Further, a transfixing slot  125  is formed perpendicular to the back side  120 A and closer to the basal portion  121  than the convex portions  124 . 
     Regarding the front side  120 B of the connection member  120  shown in  FIG. 10 , a holding portion  126  is formed on the connection member  120 . The holding portion  126  protrudes toward the engaging member  130  in the connecting position. The holding portion  126  is formed according to the shape of the engaging member  130 . Further, a click portion  127  is provided on the connection member  120 . The click portion  127  protrudes in the direction of the radius of the turning excursion. The holding portion  126  is shaped so that the holding portion  126  holds the engaging unit  130 . Described in more detail, when the holding portion  126  engages with the engaging unit  130 , the holding portion  126  encompasses three sides that include both sides of the engaging unit  130  in the direction of the short side and an upper side. 
     In addition, as shown in  FIGS. 4 ,  9 , and  10 , a D-cut plane  121   a   1  is formed in the center portion of the rotational axis  121   a  of the basal portion  121  of the connection member  120 . According to this configuration, when the connection member  120  is located at the connecting position, the D-cut plane  121   a   1  is in contact with the horizontal surface of the supporting unit  100   a   1 . 
     The connection member  120  as described above is shaded yellow while the paper feeding unit  100  (frame  101 ) and the inner wall  100   a  of the paper feeding unit  100  (frame  101 ) is shaded gray. 
     On the other hand, the engaging member  130  is formed on the printer P so that the engaging member  130  protrudes towards the inner side from the inner wall  100   a . In addition, as shown in  FIG. 4 , the engaging unit  130  protrudes in the path through which the click unit  127  passes as the connection member  120  turns. When the connection member  120  is located in the connecting position, an engaging portion  131  is formed. The engaging protruding portion  131  engages with the click unit  127  in the direction in which the engaging unit  130  turns as the engaging unit  130  moves towards the disengaging position. 
     Next, the connecting and disconnecting operations of the connection mechanism  110 , configured as above, are described. 
     First, the user makes sure that the connection member  120  is located at the disconnected position. Then, the user places the printer P above the paper feeding unit  100 . At this time, the user places the printer P so that the printer P matches the connector  111  and the positioning pin  112  shown in  FIG. 3 . 
     Next, the user pulls out and takes out the paper feeding cassette  103  equipped in the paper feeding unit  100  (frame  101 ). The user then sticks his or her hand through the cassette insertion slot  102  placed on the paper feeding unit  100  (frame  101 ), and accesses the connection member  120  which is placed in the back section (refer to  FIGS. 2 and 3 ). At this time, through the cassette insertion slot  102 , the user sees the connection member  120  placed in a dim section within the paper feeding unit  100  (frame  101 ). The user can visibly recognize the connection member  120  because the connection member  120  is placed along the direction in which the user looks through the cassette insertion unit  102 , and because the connection member  120  is shaded in a color different from the color of the inner wall  100   a.    
     When the user connects multiple paper feeding units  100  to each other, the user may take out the paper feeding cassette  103  shown in  FIG. 3 , and access the connection member  120  by placing his or her hand from above through an opening on the back side with respect to the ceiling plate  101   a  placed on the front side of the paper feeding unit  100  (frame  101 ). 
     Then, the user wraps his or her finger around the bump  124  formed on the connection member  120 . Next, the user holds the tip portion  122 . The user then rotates the connection member  120 , which is placed in the disconnected position, up by 180 degrees. Further, the user moves the connection member  120  to the connecting position shown in  FIG. 4 . The user thus connects the paper feeding unit  100  to the printer P. 
     At this time, a resistance, caused when the engaging protruding portion  131  undergoes an elastic deformation as the clicking unit  127  comes in contact with the engaging protruding portion  131  and, and an impact, caused when the resistance is released as the click unit  127  moves beyond the engaging protruding portion  131 , inform the user that a connection was made properly. Further, the click unit  127  engages with the engaging protruding portion  131 . This configuration restricts the connection member  120 , located in the connecting position, from turning towards the direction of the disconnected position. At this time, the D-cut surface  121   a   1  comes in contact with the horizontal surface of the supporting unit  100   a   1 . Consequently, the restriction of the turning, described above, becomes more reliable. 
     As shown in  FIG. 2 , the printer P, connected as described above, has a heavier weight distribution in its front side (the left side of  FIG. 2 ). As a result, the printer P is less likely to detach or fall down due to a pushing or an impact from the front side towards the back side (the right side of  FIG. 2 ). Regarding a pushing or an impact from the back side towards the front side, the printer P is less likely to detach or fall down because the connection member  120  is placed in the back side which has a lighter weight distribution. 
     Further, the printer P is shaped substantially as a rectangle in planar view. As a result, the printer P is more likely to detach or fall down due to a pushing or an impact applied in the direction of the short side compared to the direction of the long side. However, the connection member  120  is placed in both ends of the short side as shown in  FIG. 3 . Thus, a separation between a long side of the paper feeding unit  100  (frame  101 ) and the long side of the printer P is prevented because the connection member  120  appropriately receives, near these long sides, a moment by which the long side of the paper feeding unit  100  (frame  101 ) and the long side of the printer P may be separated. The moment described above is caused by a pushing or an impact in the direction of the short side. Furthermore, the rotational axis  121   a  is placed so that the axis line coincides with the direction of the short side. Consequently, the direction in which the moment is applied is perpendicular to the direction in which the connection member  120  turns. As a result, it is possible to prevent the connecting unit  120  from moving to the disconnected position due to the application of the above moment. 
     When the user disconnects the printer P which is connected as described above, the user first pulls out the paper feeding cassette  103  loaded in the paper feeding unit  100  (frame  101 ). Next, the user inserts his or her hand through the cassette insertion slot  102  placed in the paper feeding unit  100  (frame  101 ) and accesses the connection member  120  located in the back side. Further, the user turns the connection member  120  from the connecting position to the disconnected position. 
     In addition, when the user releases the connection between the paper feeding unit  100  and another paper feeding unit, the user may take out the paper feeding cassette  103 , and access the connection member  120  by placing his or her hand from above through an opening on the back side with respect to ceiling plate  101   a  placed on the front side of the paper feeding unit  100  (frame  101 ). 
     Thus, according to the present embodiment described above, a paper feeding unit, which supplies paper to an image forming apparatus and can be connected above and below, comprises: a frame; a paper feeding cassette which loads paper and can be inserted and pulled out from the frame; and a connection mechanism including a connection member and an engaging unit, wherein: the connection member can turn around a rotational axis placed in a rear anchor unit; the engaging unit is fixed to the frame; the connection mechanism is placed in the frame and can connect the image forming apparatus with the paper feeding unit, disconnect the image forming apparatus from the paper feeding unit, connect the paper feeding units to one another, and disconnect the paper feeding units from one another; the connection member of one of the paper feeding units can turn between a connection position, at which the connection member connects with the engaging unit of another paper feeding unit, and a disconnected position, at which disconnection is performed. According to the above configuration, the connection member  120 , located on the paper feeding unit  100 , turns. As a result, it is possible to connect and disconnect the paper feeding unit  100  and the printer P. Thus, tools are not necessary in order to connect and disconnect the devices. Consequently, the devices are easier to operate. 
     Therefore, the present embodiment is capable of providing a connection mechanism  110  of the printer P which can easily connect the paper feeding unit  100  and the printer P. The connection mechanism  110  is also physically stable and can be operated easily. 
     Further, according to the present embodiment, the connection member  120  is configured to be held within the paper feeding unit  100  (frame  101 ) when the connection member  120  is placed in the disconnected position. Because of this configuration, the connection member  120  will not be in the way when the paper feeding unit  100  is packaged and the like. Further, it is possible to prevent the connection member  120  from being damaged while being transported after the packaging. 
     Further, according to the present embodiment, a click unit  127  is placed on the tip portion  122  of the connection member  120 . The click unit  127  protrudes in the direction of the radius of the turning described above. The click unit  127  sticks out to the printer P along the transportation path through which the click unit  127  passes during the turning described above. At the same time, an engaging protruding portion  131  is equipped so that the engaging protruding portion  131  engages with the click unit  127  in the direction in which the connection member  120 , located in the disconnected position, turns in order to reach the above connecting position. According to this configuration, when the connection member  120  is turned to the connecting position, a resistance, caused when the clicking unit  127  comes in contact with the engaging protruding portion  131 , and an impact, caused when the click unit  127  moves beyond the engaging protruding portion  131 , informs the user that a connection was made properly. Further, the click unit  127  engages with the engaging portion  131 . This configuration restricts the connection member  120 , located in the connecting position, from turning towards the direction of the disconnected position. As a result, the paper feeding unit  100  and the printer P are more reliably prevented from separating from each other and the like. 
     Transmitting an impact to the user as described above is effective in reliably engaging the connection member  120  placed in a dimmed area. 
     According to the present embodiment, the paper feeding unit  100  (frame  101 ) is shaped approximately as a rectangle from a planar view. Multiple connection members  120  are placed along the short side of the above rectangular form. In addition, multiple connection members  120  are placed so that the rotational axis  121   a  roughly coincides with the direction of the short side. According to this configuration, it is possible to prevent the paper feeding unit  100  and the printer P from separating in the direction of the short side. The paper feeding unit  100  and the printer P are likely to become disconnected particularly in the direction of the short side when the paper feeding unit  100  is shaped approximately as a rectangle from a planar view. 
     Further, according to the present embodiment, the connection member  120  is located on both ends of the short side. Because of this configuration, the connection member  120  appropriately receives a moment when a pressing force and the like is applied from one side of the short side or the other. The moment operates to separate the paper feeding unit  100  and the printer P. The moment is caused by the pressing force and the like described above. As a result, it is possible to prevent the paper feeding unit  100  and the printer P from separating and the like. 
     Further, according to the present embodiment, the connection member  120  is located on a section of the printer P, supported by the paper feeding unit  100 , which has a lower weight distribution. Because of this configuration, it is possible to prevent the paper supplying unit  100  and the printer P from separating and the like towards the side in which there is a lower weight distribution. The paper supplying unit  100  and the printer P are likely to separate from one another towards the side in which there is a lower weight distribution when a pushing force and the like is applied. 
     Further, according to the present embodiment, a cassette insertion slot  102  is formed on the paper supplying unit  100  (frame  101 ). A paper supplying cassette  103  can be inserted to the paper supplying unit  100  (frame  101 ) via the cassette insertion slot  102 . In addition, the connection member  120  is located on the inner wall  100   a  of the paper supplying unit  100  (frame  101 ) on the side that faces the section on which the cassette insertion slot  102  is formed. Because of this configuration, it is possible to view the connection member  120  from the cassette insertion slot  102 . At the same time, a user can access the connection member  120  via the cassette insertion slot  102 . Consequently, the device becomes easy to operate. 
     Further, according to the present embodiment, the connection member  120  is located on the inner wall  100   a . As a result, it is possible to prevent the user from viewing or accessing the connection member  120  from outside the device. Consequently, it is possible to prevent the user from inadvertently disconnecting the connection member  120 . At the same time, the aesthetic design of the device is maintained. 
     Further, according to the present embodiment, the connection member  120  is shaded in a different color compared to the inner wall  100   a . Because of this configuration, it is possible to prevent the visibility of the connection member  120  from decreasing due to being placed in a dimmed area within the paper supplying unit  100 . Further, it is possible to distinguish the connection member  120  from the inner wall  100   a.    
     While a preferred embodiment of the present invention has been described above, it should be understood that these are exemplary of the invention and are not to be considered as limiting the present invention. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit or scope of the present invention. 
     For example, it was explained above that the connection member  120  according to the present embodiment is shaded yellow, which is a color different from that of the inner wall  100   a . However, the present invention is not limited to this configuration. For instance, the connection member  120  may be coated with fluorescent paint which glows in the dark. The connection member  120  may also be coated with gold or silver and the like, which easily reflect light. 
     The invention is not to be considered as being limited by the foregoing description, and is only limited by the scope of the appended claims.