Patent Publication Number: US-8971757-B2

Title: Image forming device

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation of prior U.S. application Ser. No. 11/391,253, filed Mar. 29, 2006, which claims priority to JP 2005-98877 filed Mar. 30, 2005, which applications are herein incorporated by reference. 
    
    
     FIELD 
     Aspects of the present invention relates to an image forming device. 
     BACKGROUND 
     An arrangement which allows items housed within a device main body to be pulled outside the main body has been proposed in the field of image forming devices. Using such an arrangement makes it easier for an operator to access specific components arranged at locations deep inside the device during use (during image forming), increasing the convenience of maintenance. An arrangement of this sort, which enables items housed inside a device main body to be pulled out of the main body, includes for example that of Japanese Unexamined Patent Application Publication H5-257340. 
     However, with an arrangement that allows items housed inside the device main body to be pulled out of the main body as described above, the device can be easily overturned due to the pull-out. In particular, providing a tray which can be pulled out in cantilever fashion above a housing element which houses a recording medium allows access to housed items other than the recording medium, but the load on the tray when it is pulled out acts strongly upon the device main body via the tray, so the device as a whole can easily overturn. 
     SUMMARY 
     Aspects of the invention allow items housed inside the device main body to be pulled out while making it difficult for the device to overturn during pull-out. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a lateral cross-section of a color laser printer according to at least one aspect of the present invention. 
         FIG. 2  illustrates a cross-sectional schematic of the frontal cross-section of the color laser printer shown in  FIG. 1 . 
         FIG. 3  illustrates a process of pulling out the tray according to at least one aspect of the invention. 
         FIG. 4A  illustrates a tray suspended from a pivotal support element according to at least one aspect of the invention. 
         FIG. 4B  illustrates a process of pulling out the tray according to at least one aspect of the invention. 
         FIG. 5A  illustrates a lateral cross-section of another color laser printer according to at least one aspect of the invention. 
         FIGS. 5B  and C illustrate another process of pulling out a tray according to at least one aspect of the invention. 
         FIG. 6  illustrates how a tray is supported on the installation surface according to at least one aspect invention. 
         FIG. 7  illustrates a click mechanism according to at least one aspect of the invention. 
         FIG. 8  illustrates a resistance imparting mechanism according to at least one aspect of the invention. 
         FIG. 9A  illustrates a cross-section of another color laser printer according to at least one aspect of the invention. 
         FIGS. 9B  and C illustrate another process of pulling out a tray according to at least one aspect of the invention. 
         FIG. 10A  illustrates a lateral cross-section of another color laser printer according to at least one aspect of the invention. 
         FIGS. 10B  and C illustrate another process of pulling out a tray according to at least one aspect of the invention. 
         FIG. 11A  illustrates a lateral cross-section of another color laser printer according to at least one aspect of the invention. 
         FIGS. 11B  and C illustrate another process of pulling out a tray according to at least one aspect of the invention. 
         FIG. 12A  illustrates a lateral cross-section of another color laser printer according to at least one aspect of the invention. 
         FIG. 12B  and C illustrate another process of pulling out a tray according to at least one aspect of the invention. 
         FIG. 13  illustrates an application of a tray with a front cover according to at least one aspect of the invention. 
         FIG. 14  illustrates an application of a tray in which a belt unit can be placed according to at least one aspect of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     Illustrative Aspects 
     Aspects of the present invention will be described with reference to the drawings.  FIG. 1  is a simplified drawing representing the internal configuration of a color laser printer  1  according to at least one aspect of the present invention. 
     An image forming device in the form of the color laser printer  1  is illustrated in  FIG. 1 . The color laser printer  1  includes a toner image forming unit  4 , a paper conveying belt  6 , fixing unit  8 , paper feed unit  9 , paper ejection platform  52  and control unit  10 , and forms a four-color image on paper P corresponding to image data input from outside. Paper P corresponds to an illustrative recording medium. 
     The toner image forming unit  4  includes four developing units  51 M,  51 C,  51 Y, and  51 BK, and a photosensitive drum  3 , charging device  31 , and exposure device  41  for each of the four toner image processes using the magenta (M), cyan (C), yellow (Y), and black (BK) toners stored in the development units  51 M,  51 C,  51 Y, and  51 BK. 
     The developing units  51 M,  51 C, and  51 Y have the same configuration as the black developing unit  51 BK, and in  FIG. 1 , the representative internal configuration is illustrated only for the black developing unit  51 BK and is shown in simplified fashion for the other developing units  51 M,  51 C, and  51 Y. Furthermore, in  FIG. 2  and subsequent figures, these developing units  51 M,  51 C,  51 Y, and  51 BK are shown in simplified fashion. 
     The photosensitive drum  3  of the toner image forming unit  4  includes a substantially cylindrical member. Four such drums are lined up horizontally at substantially equal spacing and mounted rotatably about a photosensitive element drum shaft  3   a . For the substantially cylindrical member of the photosensitive drum  3 , an aluminum base material with a positively charged photosensitive layer formed thereon, for example, may be used. The aluminum base material can be grounded to the ground line of the color laser printer  1 . 
     The charging device  31  is a so-called scorotron charging device, which includes a charging wire  32  arranged opposite the photosensitive drum  3  and extending in a widthwise direction, and a shielded case  33  which houses the charging wire  32  and is open on the photosensitive drum  3  side. Applying a high voltage to this charging wire  32  causes the surface of the photosensitive drum  3  to be charged to a positive polarity. Furthermore, the shielded case  33  has a structure with a grid provided at the open part on the photosensitive drum  3  side. Applying a rated voltage to this grid causes the surface of the photosensitive drum  3  to be charged to substantially the same potential as the rated voltage. In  FIG. 2  and subsequent figures, the charging device  31  is shown in simplified fashion. 
     Furthermore, the exposure device  41  is rotationally driven by a polygonal motor  26 , irradiating the surface of the photosensitive drum  3 . The exposure device  41  is arranged to expose each photosensitive drum  3  downstream of the charging device  31  in the direction of rotation of the photosensitive drum  3  by emitting laser light from a light source according to image data of one color input from outside, and scanning the laser light with a polygonal mirror or the like. In  FIG. 1 , the representative internal configuration is shown for the exposure device  41  corresponding to the black developing unit  51 BK. The exposure devices  41  corresponding to the developing units  51 M,  51 C, and  51 Y have the same structure and are shown in simplified fashion. In  FIG. 2  and subsequent figures, all exposure devices  41  are shown in simplified fashion. 
     When the surface of the photosensitive drum  3  is irradiated with laser light corresponding to image data by the exposure device  41 , the surface potential of the irradiated area drops, and a static latent image is formed on the surface of the photosensitive drum  3  as a result. 
     As illustrated representatively for developing unit  51 BK, the developing units  51 M,  51 C,  51 Y, and  51 BK include a developing unit case  55  which houses toner and is provided with a developing roller  50 . The developing units  51 M,  51 C,  51 Y, and  51 BK are arranged so that the developing roller  50  contacts the photosensitive drum  3  downstream of the exposure device  41  in the direction of rotation of the photosensitive drum  3 . The developing units  51 M,  51 C,  51 Y, and  51 BK give a “+” (positive polarity) charge to the toner and supply the charge in a uniform thin layer to the photosensitive drum  3 , and the “+” (positive polarity) charged toner is developed by a reversal development method in response to the “+” (positive polarity) static latent image formed on the photosensitive drum  3  at the contact position between the developing roller  50  and the photosensitive drum  3 . 
     The developing roller  50  is fashioned in a cylindrical shape with conductive silicone rubber or the like as the base material, with a coating layer of rubber material or resin containing fluorine formed on the surface thereof. 
     Furthermore, the toner contained in the developing unit case  55  is a positive charging non-magnetic one-component toner, with the developing units  51 M,  51 C,  51 Y, and  51 BK holding magenta, cyan, yellow, and black toner, respectively. 
     Furthermore, the paper feed unit  9  is provided in the lowermost part of the device and includes a housing cassette  91  which houses paper P and a pick-up roller  92  which feeds out the paper P. The paper P housed in the housing cassette  91  is extracted one sheet at a time by the pick-up roller  92  from the paper feed unit  9  and is fed to the paper conveying belt  6  by conveying rollers  99  and the like. 
     Furthermore the paper conveying belt  6  is fashioned as an endless belt to travel integrally with the paper P carried on its top surface and circulates over a drive roller  62  and follower roller  63 , with transfer rollers  61  being arranged near the location opposite each photosensitive drum  3 . 
     As shown in  FIG. 1 , the surface  6 a of the paper conveying belt  6  on the side facing the photosensitive drum  3  is moved by the rotation of drive roller  62  from left to right in the drawing, and pieces of paper arriving from the conveying rollers  99  are conveyed sequentially between the photosensitive drum  3  and the belt and sent to the fixing unit  8 . 
     Each transfer roller  61  can be connected to a constant current source (not shown), and is configured so that a transfer bias of opposite polarity to the polarity of the toner charge is applied between the transfer roller  61  and the photosensitive drum  3  from the constant current source when transferring toner to the transfer target element (paper P), whereupon the toner image formed on the photosensitive drum  3  is transferred to the paper P being conveyed by the paper conveying belt  6 . 
     The fixing unit  8  includes a heating roller  81  and a pressurizing roller  82 , applying heat and pressure to paper P to cause the toner image to be fixed to the paper P. Paper P carries a four-color toner image while being conveyed between the heating roller  81  and the pressurizing roller  82 . 
     Furthermore, a paper ejection platform  52  is formed on the top surface of the color laser printer  1 . The paper ejection platform  52  is provided on the paper ejection side of the fixing unit  8  and holds paper ejected from the fixing unit  8 . 
     Next, the operation of forming an image on the paper P in the color laser printer  1  will be described. First, one sheet of paper P is supplied by the pick-up roller  92  from the paper feed unit  9  illustrated in  FIG. 1 , and is fed to the paper conveying belt  6  via conveying rollers  99 . 
     Next, the surface of the leftmost photosensitive drum  3  in  FIG. 1  (i.e. the photosensitive drum  3  corresponding to the magenta developing unit  51 M) is charged uniformly to a prescribed voltage by the charging unit  31  and is exposed by exposure unit  41  in accordance with the magenta image data input from outside. The potential of just the exposed area falls, forming a static latent image. Next, in the developing unit  51 M, magenta toner charged to a positive polarity by developing roller  50 , to which a positive developing bias is applied, is supplied to the surface of the photosensitive drum  3  to carry out development, with the magenta toner adhering only to areas where the static latent image has been formed and the potential has been reduced by the developing bias. The “+” (positive polarity) charged toner image formed in this manner is then transferred to the surface of the paper P conveyed by the paper conveying belt  6  by the transfer roller  61 , to which a negative polarity transfer bias is applied. After this transfer has been carried out, the magenta toner charged to a “+” (positive polarity) and transferred to the paper P by transfer roller  61  adheres to the paper P. 
     Next, the paper P is sequentially conveyed to the locations opposite the photosensitive drums  3  for cyan toner, yellow toner and black toner, and by the same procedure as for magenta toner, a toner image can be formed on the surface of the photosensitive drum  3  and overlaid onto the paper P by the transfer roller  61 . Finally, the four-color toner image formed on the paper P is fixed on the paper P in the fixing unit  8 , and the paper P is ejected to the paper ejection platform  52 . 
     Next, the tray will be described. 
       FIG. 2  shows the frontal cross-section of color laser printer  1  (cross-section near A-A in  FIG. 1 ), with some of the components being shown in simplified fashion.  FIGS. 3A  through C explain the process of pulling out the tray according to aspects of the invention.  FIG. 3A  illustrates the state of  FIG. 1  in simplified fashion, while  FIGS. 3B  and C present the inside of the device in a side view along with a conceptual representation of a partial cross-section of a wall area. 
     In the color laser printer  1  according to at least one aspect, a tray  11 , in which the developing units  51 M,  51 C,  51 Y, and  51 BK are placed, is arranged above the holding cassette  91  which holds the paper P. In this description, “upward” signifies vertically upward and “downward” signifies vertically downward. This tray  11 , as illustrated in  FIG. 2 , is configured to be supported by a guide groove  20  and to slide along this guide groove  20 . Furthermore, this tray  11  is made displaceable independently of the holding cassette  91 , and can be pulled out from the device main body  1   a  while leaving the holding cassette  91  inside the device main body  1   a.    
     According to certain aspects, a pair of protrusions  12  (see also  FIGS. 3B  and C) is provided at the upstream end in the pull-out direction of tray  11 , and the guide groove  20  is provided to support these protrusions  12 . The protrusions  12  are configured to protrude outward in the widthwise direction from the two sidewalls of the tray  11 , as shown in  FIG. 2 . 
     The guide groove  20 , as shown conceptually in  FIGS. 3B  and C, is formed into a groove shape in a direction substantially parallel to the installation surface F in the wall areas  71  and  72  ( FIG. 2 ). In the example of  FIG. 2 , the guide groove  20  is also configured so as to support the bottom end part of the tray  11  other than the protrusions  12  (specifically, the two widthwise ends of the bottom end part). This arrangement allows the tray  11  to move along the guide groove  20  and makes it possible to pull out the whole unit  10  along the installation surface F. 
     To pull out the unit  10  including the tray  11 , first, from the state of  FIG. 3A , the front cover  2   a  is opened, the front cover being arranged to be opened and closed on the front surface of the main body casing  2 . The opening  30  formed in the device main body  1   a  can be exposed as a result, as shown in  FIG. 3B , and the tray  11  becomes accessible through the opening  30 . Then, from the state of  FIG. 3B , the tray  11  is pulled out until the protrusions  12  engage with the pivot support elements  100  at a pulled out position, whereupon the unit  10  moves out of the main body casing  2 . 
     A pair of pivot support elements  100  is provided to support the pair of protrusions  12  (only one of the elements is illustrated in  FIG. 3 ), and the existence of this pivot support element  100  makes it possible to pivot the tray  11  (and thus, the unit  10 ) centered about the protrusions  12 . Specifically, after pulling the unit  10  out of the main body casing  2  to the pulled out position, the downstream side of the unit  10  in the pull-out direction is pivot downward (toward the installation surface F), as a result of which a portion of the downstream side of the tray  11  (specifically, the corner part  11   a ) comes to be directly supported on the installation surface F on which the color laser printer  1  is installed, as illustrated in  FIG. 3C . In other words, a tilted state is assumed, with the protrusions  12  formed on the upstream side being supported by the pivot support element  100  and the angle part  11   a  on the downstream side being supported by the installation surface F. The “directly supported arrangement” referred to here is the arrangement whereby a portion of the tray  11  directly contacts the installation surface F, as illustrated in  FIG. 3C . 
     According to some aspects, when the tray  11  is pulled out from the main body casing  2 , the upstream side can be supported on the main body casing  2  side while the downstream side can be supported by utilizing the installation surface F, so the tray  11  is not cantilevered, making it possible to effectively prevent overturning of the device. In devices with the tray  11  being arranged to be pulled out above the holding cassette  91  which holds the paper, if the tray is cantilevered, a large force will be applied upward, making the device prone to overturning. The arrangement whereby a portion of the downstream side of the tray  11  is supported on the installation surface, as in  FIG. 3C , or the arrangement whereby a portion of the downstream side of the tray  11  pivots downward ( FIG. 4B , described below)) can make a device less susceptible to overturning. 
     Furthermore, pivot support element  100  is made displaceable between an in-use position (i.e. a forward position) protruding downstream in the pull-out direction of the tray  11  from the main body casing  2   a  of the device main body  1   a  (the position in  FIG. 3B ) and a retracted position in which it is housed inside the main body casing  2  (the position in  FIG. 3A ). Specifically, when in the retracted position as in  FIG. 3A , the pivot support element  100  is supported at the front by the front cover  2   a  while being impelled in the direction of pivoting by a spring member  40 , and when the front cover  2   a  opens, the front support is removed, and the pivot support element  100  is displaced by the spring member  40  to the in-use position as shown in  FIG. 3B . This arrangement makes it possible to house the pivot support element  100  inside the main body casing  2  when not pivoting the tray  11 , allowing the device to be made more compact. The arrangement shown here is only an example. Other arrangement may be used so long as they allow the displacement between an in-use position protruding out from the main body casing  2  and a retracted position housed within the main body casing  2 . For example, an arrangement can be used whereby displacement between the in-use position and retracted position is accomplished by rotation. 
     Moreover, since according to some aspects, protrusions  12 , constituting the first supported part, are provided on the tray  11  on the upstream side in the pull-out direction, and the pivot support element  100  is provided in the device main body  1   a  at the downstream side end in the pull-out direction of the tray, the space needed for sliding inside the device main body  1   a  can be reduced. Therefore, it becomes less likely for other elements to be restricted by the arrangement for sliding, increasing the degree of freedom of device configuration. 
     Furthermore, since in some aspects, the existence of the pivot support element  100  allows the part of the tray  11  downstream of the protrusions  12  to be pivoted downward when pulled out from the device main body  1   a  to the pulled out position, the center of gravity of the tray  11  can be brought closer to the device main body side by pivoting as compared to a cantilevered state where the tray  11  is just pulled out horizontally. Therefore, even with an arrangement where a portion of the downstream side of the tray  11  cannot be supported, as in  FIG. 4A , the unit  10  is suspended from the pivot support element  100 , so it is still possible to provide a support that makes overturning less likely than in a cantilevered arrangement. In other words, since the moment generated on the device main body  1   a  can be made smaller as compared to the case of pulling out into a cantilevered state, the device becomes less prone to being upset, providing for an arrangement which allows overturning of the device to be effectively suppressed. 
     In this way, by pivoting the tray  11 , the tray  11  can be suspended in a position near the device main body  1   a , as shown in  FIG. 4A , or to support a portion of the downstream side of the tray  11  in the pull-out direction on the installation surface, as shown in  FIG. 3C , and using either of these support methods allows for a more stable support which makes toppling less likely than when the tray is held in a cantilevered state. 
     In addition to being supportable on the pivot support element  100 , as shown in  FIG. 3C  and  FIG. 4A , the tray  11  can also be detached from the device main body  1   a , as shown in  FIG. 4B . In other words, the upper part of the pivot support element  100  is open, and moving the unit  10  upward from the state of  FIG. 3C  or  FIG. 4A  allows the tray  11  to be detached from the device main body  1   a . This arrangement makes it easier to access the items held inside the tray  11  which can improve workability during maintenance. 
     Furthermore, as discussed above, the developing apparatus, i.e. the developing units  51 M,  51 C,  51 Y, and  51 BK are placed in the tray  11 , and a configuration which places the developing apparatus, with its high replacement frequency, into the tray  11  also increases the frequency of pulling out of the tray  11 . The arrangement can prevent overturning of devices with this sort of configuration, so the operator does not need to always be concerned about overturning when pulling out the tray, making for an arrangement which is very easy to use for the operator. 
     Next, aspects of the present invention will be described with reference to  FIGS. 5 through 8 .  FIG. 5A  is a lateral cross-section schematically illustrating the configuration of the color laser printer according to at least one aspect.  FIGS. 5A  through C explain the process of pulling out the tray.  FIGS. 5B  and C provide a simplified side view of the inside of the device along with a conceptual representation of a partial cross-section of a wall area. Furthermore,  FIG. 6  is an illustration explaining the state where the tray is supported on the installation surface,  FIG. 7  is an illustration explaining the click mechanism, and  FIG. 8  is an illustration explaining the resistance imparting mechanism. The arrangement includes both the click mechanism  120  shown in  FIG. 7  and the resistance imparting mechanism  130  shown in  FIG. 8 , but for ease of explanation, the resistance imparting mechanism has been omitted from  FIG. 7  and the click mechanism has been omitted from  FIG. 8 . 
     As shown in  FIG. 5A , developing units  51 M,  51 C,  51 Y, and  51 BK are arranged above the holding cassette  91 . A tray  11  is provided for loading the developing units as shown in  FIG. 5B . The device is configured such that the tray  11  can be pulled out from the device main body  1   a  while leaving the holding cassette  91  inside the device main body  1   a , as shown in  FIGS. 5A  and B. Furthermore, protrusions  12  are provided on the upstream side of the tray  11  in the pull-out direction, and guide grooves  30  capable of supporting the protrusions  12  are provided in the device main body  1   a . The guide grooves  30  are formed in the wall areas in the same way as described according to another aspect ( FIG. 5  shows only one of the wall areas  71 ). 
     A pivot support element  200  which pivotally supports the tray  11  centered on the protrusions  12  is provided in the device main body  1   a  at the downstream end in the pull-out direction (specifically, near the downstream end of the guide grooves  30 ). In this aspect, the existence of the pivot support element  200  allows the downstream portion of the tray  11  to be pivoted downward while pulling the tray out from the device main body  1   a.    
     This downward pivoting allows the tray  11  to be supported on the installation surface via another member, as shown in  FIG. 6 . Specifically, a convex element  17  is mounted on the downstream bottom end of the tray  11 , and the tray  11  is configured to be supported on the installation surface F by convex element  17 . A pair of convex elements  17  is provided at the locations of the two widthwise ends of the tray  11 , supporting the tray while maintaining its balance in the widthwise direction. According to other aspects the tray  11  can be supported directly on the installation surface as described above. Conversely, it is also possible to provide a convex element similar to convex element  17  of  FIG. 6  in aspects of the invention including those described previously  1 . 
     The pivot support element  200 , as illustrated in  FIG. 7A , is provided with a click mechanism  120  which changes the withdrawal force in the pull-out direction of tray  11  between an installation position at which the tray  11  is installed in the device main body  1   a  and a pivot position at which pivoting becomes possible based on support by the pivot support element  200 . This click mechanism  120  includes a pivoting member  121  pivotable about a shaft  121   a , and a spring member  122  capable of impelling the pivoting member  121 . In  FIG. 7A , the spring member  122  is in its natural state, in which state, the convex part  121   b  formed in the pivoting member  121  protrudes so as to overlap the guide groove  30  in the vertical direction. Then, as shown in  FIG. 7B , once the protrusion  12  moves downstream as the tray  11  is pulled out, the pivoting member  121  moves upward against the impelling force of the spring member  122 , with a load being applied by the spring member  122  and convex part  121   b  as the tray is moved. The load lets the operator know that the tray  11  has moved close to the end. If the movement of the tray  11  progresses further, the protrusion  12  moves downstream of the convex part  121   b  of the pivoting member  121 , reaching the pull-out position where the tray  11  can be pivoted, as shown in  FIG. 7C . At the end of the guide groove  30 , there is formed a bearing part  30   a , which has a circular arc shaped cross-section. Upon reaching the end of the guide groove  30 , the protrusion  12  becomes rotatable. Since the load disappears at this rotatable position, the operator can know, based on this change in load, that the tray  11  has reached the pivotable position and the pull-out position. Configuring the click mechanism  120  in this manner gives the operator a sense of clicking and allows the operator to be provided with an indication that tray is near the pivoting position. It will be appreciated that other structures and devices could be used to provide an indication that the tray is approaching the pivoting position such as a detector, which provides visual or aural feedback, all of which are within the scope of the invention. 
     According to a least one aspect, a pair of flat parts  12   a  and  12   b  is formed on the protrusion  12 . These flat parts  12   a  and  12   b  are designed to fit the guide groove  30 . When the protrusion  12  has not yet reached the end, as in  FIGS. 7A  and B, the flat parts  12   a  and  12   b  engage the guide groove  30 , making rotation impossible, and once the protrusion  12  reaches the bearing part  30   a  as in  FIG. 7C , this engagement is cancelled, and the protrusion  12  becomes rotatable. 
     Furthermore, the pivot support element  200  is provided with a resistance imparting mechanism  130 , as shown in  FIG. 8 , which imparts a force resisting the pivoting of the tray  11  when the tray  11  is pivoted. The resistance imparting mechanism  130  includes a rotating member  131  which rotates about a shaft  131   a  and a spring member  133  which impels the rotating member  131 . Furthermore, an extension  11   b  is formed upstream of the tray  11 , and a second protrusion  125  is formed on the extension  11   b . As shown in  FIGS. 8A , B, and C, when the tray  11  pivots at the pivoting position, the second protrusion  125  moves along a groove  35  formed by a pair of wall areas (here, only wall area  71  is illustrated). Here, the second protrusion  125  moves along the groove  35  while pushing away the rotating member  131 , at which time a load is applied from the spring member  133 . In other words, while the second protrusion  125  is moving through the groove  35 , as shown in  FIGS. 8B  and C, the rotating member  131  is constantly impelled by the spring member  133 , generating friction between the rotating member  131  and the second protrusion  125 . A force resisting the pivoting of the tray  11  is imparted by this friction. The resistance imparting mechanism  130  fashioned in this manner can suppress abrupt pivoting of the tray  11 , which can prevent problems due to abrupt pivoting. 
     Furthermore, the pivoting of the tray  11  upward from a horizontal state is constrained. Namely, if one attempts to pivot the tray  11  further upward from the horizontal state shown in  FIG. 8A , the second protrusion  125  will come into contact with the bottom wall part of the guide groove  30 , thereby constraining the upward pivoting of the tray  11 . This arrangement prevents the tray  11  from pivoting upward more than necessary, providing for greater ease of use. 
     Furthermore, the arrangement according to some aspects also allows the center of gravity of the tray  11  to be brought closer to the device main body by pivoting as compared to when the tray  11  is pulled out horizontally into a cantilevered state. So even with an arrangement where a portion of the downstream side of the tray  11  cannot be supported, by suspending the unit  10  from pivoting support element  200 , as shown in  FIG. 8C , it is still possible to provide support that makes overturning less likely than in the cantilevered case. 
     In this way, the tray  11  can be suspended in a position near the device main body  1   a , as shown in  FIG. 8C , or to support a portion of the downstream side of the tray  11  in the pull-out direction on the installation surface, as shown in  FIG. 6 . Using either of these support methods allows for a more stable support which makes toppling less likely than when the tray  11  is held in a cantilevered state. 
       FIG. 9A  is a lateral cross-section schematically illustrating the color laser printer according to aspects of the invention  FIGS. 9B  and C are illustrations schematically showing how a tray is pulled out of the color laser printer  1 . 
     According to some aspects, the tray  11  can be supported indirectly by another member. Specifically, legs  105  can be provided to support the second supported part (the part supported by the legs  105 ) of the tray  11  pulled out from the device main body  1   a  in a state where the legs contact the installation surface F. The legs  105  are provided in a pair, one on each widthwise end of the tray  11 , and support the tray while maintaining its balance in the widthwise direction. In  FIG. 9C , only the near side leg  105  is shown. 
     In some aspects, the front cover  2   a  is designed to rotate up to 90° from the closed state of  FIG. 9A , as shown in  FIG. 9B , and to not rotate any further downward from that position. The legs  105  are impelled downward by a spring member  109 , whereby the tray  11  is maintained in a substantially horizontal state when the legs  105  are in contact with the installation surface F. Furthermore, the legs  105  are configured to be supported by the edge of the front cover  2   a  when rotated 90° as in  FIG. 9C , providing for a structure which makes the legs  105  more stable. While in the example shown here, a pair of legs  105  were provided at the two widthwise ends of the tray  11 , the number of legs can also be three or more, or a single leg spanning a prescribed region in the widthwise direction of the tray  11  may also be used. 
     In some aspects, the legs  105  can be fashioned to be foldable and to be housed in the device main body  1   a  when not being used, allowing the device to be made more compact. 
     The legs  105  are provided with a rolling member  107  capable of rolling in the position where it contacts the installation surface F. Through the support of the legs  105 , the tray  11  is supported in a horizontal state over the installation surface F via the legs  105 . An arrangement which allows the tray to be supported in a horizontal state in this manner allows the tray  11  to be handled more easily and stably, since there is no need to tilt the tray  11 . Of course, this arrangement can also prevent overturning of the device main body. 
       FIG. 10A  is a lateral cross-section schematically illustrating the color laser printer according to aspects of the invention.  FIGS. 3B  and C are illustrations explaining how the tray is pulled out of the color laser printer of  FIG. 10A . 
     In some aspects the tray  11  can be supported indirectly by another member, wherein, similarly to  FIG. 9A , legs  110  can be provided to support the second support part of the tray  11  (the part supported by the legs  110 ) pulled out from the device main body  1   a  when the legs contact the installation surface F. 
     The legs  110  can be fashioned integrally with the tray  11  so as to extend downward from the tray  11 . Furthermore, the legs  110  can be provided with a rolling member  111  capable of rolling in the position where it contacts the installation surface F. Furthermore, the tray  11  can be supported in a horizontal state over the installation surface F by the legs  110 . Moreover, as shown in  FIG. 10C , the tray  11  can be configured such that it can be removed from the device main body  1   a  (specifically, with the developing units  51 M,  51 C,  51 Y, and  51 BK loaded in the tray). 
     In some aspects, the legs  110  can be provided in a pair, one at each widthwise end of the tray  11  (in  FIG. 10A  through C, only the near side leg  110  is shown), and the legs  110  support the tray  11  while maintaining its balance in the widthwise direction. Furthermore, in the case of  FIG. 10 , the legs  110  can be arranged at the two sides in the widthwise direction of the front cover  2   a  arranged to be opened and closed at a position in front of the tray  11 , and include an extension  110   a  which extends upstream in the pull-out direction. This extension  110   a  is designed to retain the tray  11  and to move in and out of the device main body  1   a  at the side of the front cover  2   a . When the front cover  2   a  is open, the area in front of the tray  11  is opened up and the legs  110  and tray  11  can be integrally pulled out, as shown in  FIG. 10B . The extension  110   a  and the tray  11  are made detachable, and pulling out the tray  11  as shown in  FIG. 10C  allows it be completely detached, as discussed above. 
     While in the example shown here the legs  110  and the front cover  2   a  were fashioned separately, it is also possible to configure a portion of the component constituting the legs  110  as the front cover. Furthermore, while in the example shown here, a pair of legs  110  was provided at the two widthwise ends of the tray  11 , the number of legs can also be three or more, or a single leg spanning a prescribed region in the widthwise direction of the tray  11  may also be used. 
       FIG. 11A  is a lateral cross-section schematically illustrating the color laser printer according to aspects of the invention.  FIGS. 3B  and C are illustrations explaining how the tray is pulled out from the color laser printer in  FIG. 11A . 
     Aspects involve a partial modification of  FIG. 10 . Specifically, the legs  114 , which have substantially the same configuration as legs  110  of  FIG. 10 , are fashioned as separate components from the tray  11 , and are mounted detachably on the tray  11 . This arrangement makes it possible to remove the legs  114  if required, allowing them to be used as appropriate for the circumstances. 
     The legs  114  can be provided in a pair, mounted at positions at the two widthwise ends of the tray  11  (more specifically, at positions outward from the front cover  2   a  in the widthwise direction) (in  FIGS. 11A  through C, only the near side leg  110  is shown) The legs are designed to support the tray  11  while maintaining its balance in the widthwise direction. In the example of  FIG. 11 , a space for inserting the legs  114  (not shown) is provided at the sides of the front cover  2   a . This space can be made to be opened and closed by a separate component from the front cover  2   a , or can be always left open if the space is small. Furthermore, in some aspects, a rolling member  115  can be provided below the legs  114 . While here a pair of legs  110  was provided at the two widthwise ends of the tray  11 , the number of legs can also be three or more, or a single leg spanning a prescribed region in the widthwise direction of the tray  11  may also be used. 
     In  FIG. 12 , a support mechanism  140  can be provided to be relatively displaceable with respect to the device main body  1   a  independently of the tray  11 . In some aspects, the mechanism for displacing the tray  11  is made separate from the mechanism for displacing the downstream supporting part (i.e. the mechanism for displacing the support mechanism  140 ). Doing so allows the mechanisms for displacing the individual components to be fashioned with a greater degree of freedom. 
     The support mechanism  140  can be configured to be foldable and to be housed in the device main body  1   a  in the folded state. More specifically, a portion of the support mechanism  140  doubles as the front cover  2   a , and the support mechanism  140  can be fashioned such that the frames  140   a  and  140   b  and the supporting part  140   e  spring upward when the front cover  2   a  is lowered, as shown in  FIG. 12B . The frames  140   a  and  140   b  and the supporting part  140   e  are provided in a pair to support the widthwise ends of the tray  11  and are fashioned to support the tray  11  while maintaining its balance in the widthwise direction. In the example of  FIG. 12 , only the near side frames  140   a  and  140   b  and supporting part  140   e  are illustrated. 
     The frames  140   a  and  140   b  of the support mechanism  140  are impelled by spring members  140   c  and  104   d , and in the supporting state, the supporting part  140   e  which receives the tray  11  is maintained in an impelled state where it is pushed upward, as shown in  FIG. 12B  and C. In this state, when the tray  11  is pulled out, the tray  11  becomes supported in a horizontal state above the installation surface F as shown in  FIG. 12C . Furthermore, when the frames  140   a  and  140   b  and the supporting part  140   e  are folded against the impelling force of the spring members  140   c  and  140   d  and the front cover  2   a  is closed, the support mechanism  140  becomes housed inside the device main body  1   a , as shown in  FIG. 12A . Although not illustrated in  FIG. 12 , a rolling member may also be provided at the upper end of the support mechanism  140 . 
     Aspects of the present invention are not limited to those explained in the above descriptions and drawings. For example, the following aspects are also included within the technical scope of the present invention, and other aspects beside those indicated below are also possible. 
     (1) In the above-described aspects, the image forming device can be a printing device other than a color laser printer a facsimile machine, a combination device with a printer function and scanner function, or the like. 
     (2) The recording medium is not limited to paper or paper based recording media, and can be for instance a plastic recording medium such as OHP sheets. 
     (3) In the above-described aspects, a tray into which a development apparatus is placed was illustrated, but the tray is not limited to this configuration as long as the tray can be pulled out above the housing element which houses the recording medium. For example, can also be applied to a tray with a front cover, as illustrated in  FIG. 13  (i.e. an arrangement wherein a portion of the tray functions as the front cover  15 ).  FIG. 13A  is a lateral cross-section schematically illustrating an example in which aspects of the present invention are applied to a tray with a front cover.  FIGS. 13  B and C are illustrations explaining how the tray is pulled out in this configuration. Furthermore, aspects can be applied to a tray which holds a belt unit, as shown in  FIG. 14 . Furthermore, aspects of the invention are not limited to these arrangements, and the tray can hold components other than a developer apparatus.