Abstract:
A recording apparatus includes a discharging roller for discharging, from a main assembly of the apparatus, a recording material having been subjected to a recording operation by recording means; an openable and closable sheet discharge tray for supporting the recording material discharged by the discharging roller; locking means for holding the sheet discharge tray at a closed position; drive transmitting means for transmitting a driving force to release the locking means in interrelation with main assembly driving means; and advancing and retracting means for advancing and retracting the drive transmitting means relative to the main assembly driving means in interrelation with a position of the sheet discharge tray, wherein the locking means is effective to release the locking means by the main assembly driving means so as to permit the drive transmitting means to retract away from the main assembly driving means by a weight of the sheet discharge tray and an urging force of urging means when the sheet discharge tray is at the closed position.

Description:
FIELD OF THE INVENTION AND RELATED ART 
       [0001]    The present invention relates to a recording apparatus which records on recording medium with the use of recording means, based on picture information. More specifically, it relates to a recording apparatus equipped with a mechanism for automatically unfolding a delivery tray. 
         [0002]    A recording apparatus, such as a printer, a copying machine, a facsimile machine, etc., is structured to record an image on recording medium, such as recording paper, etc., based on picture information. As recording methods employed by a recording apparatus, there are various methods, for example, the thermal transfer method, thermal method, ink jet recording method, laser beam recording method, wire-dot recording method, etc. As for recording media, there are also various media, for example, paper, fabric, plastic sheet, OHP sheet, envelop, etc. In other words, anything can be used as recording medium as long as an image is recordable thereon. Further, recording apparatuses of various types have come to be used as the means for printing a text or pictorial image based on information sent from a personal computer, a digital camera, or the like. 
         [0003]    A recording apparatus is provided with a delivery tray, which is for preventing the sheets of recording medium from changing in order after printing, preventing the sheets of recording medium (copies) from being soiled by falling to the floor, and/or preventing the like problems. A delivery tray is required to hold various recording media, as well as multiple sheets of recording medium, in an orderly fashion. Therefore, its size (length as well as width) needs to be greater than a certain value. Thus, in recent years, a delivery tray has been made foldable so that when it is not in use, it can be kept folded. Making the delivery tray of a recording apparatus foldable can reduce the recording apparatus in the amount of space the recording apparatus occupies when the apparatus is not in use, and also, can improve the appearance of the recording apparatus when it is not in use. It also can protect the interior of the recording apparatus from dust or the like. 
         [0004]    However, a foldable delivery tray has the following problem: If a recording apparatus equipped with foldable delivery tray is operated with the tray remaining in the folded state, recording mediums are prevented from being discharged from the apparatus, becoming therefore jammed in the apparatus, after recording is made thereon. As the means for solving this problem, Japanese Laid-open Patent Application 2004-82473 discloses a recording apparatus which is provided with a sensor for detecting the state of its delivery tray (whether or not delivery tray is in the folded state), so that a warning is issued, or the on-going printing operation is interrupted. Further, Japanese Laid-open Patent Application 2005-74659 discloses a recording apparatus structured so that its delivery tray is automatically unfolded by a delivery tray operating power source, such as a solenoid, dedicated to the tray, as soon as the power source of the recording apparatus is turned on, or in response to a command for starting a printing operation. 
         [0005]    However, the automatically unfoldable delivery trays, such as the abovementioned ones, which are in accordance with the prior art suffer from the following problems. That is, they require a dedicated sensor, a dedicated driving power source, and the wiring therefor, and therefore, providing a recording apparatus with an automatically unfolding delivery tray in accordance with the prior art substantially increases the apparatus cost. In other words, only an expensive recording apparatus can be equipped with an automatically unfolding delivery tray. As one of the means for keeping the cost of a recording apparatus equipped with an automatically unfolding delivery tray as low as possible, it is possible to employ a solenoid as the driving force source. However, the employment of a solenoid has its own problem, because a solenoid generates loud noises as it is driven. 
         [0006]    A recording apparatus which is provided with a sensor for detecting the state (whether its delivery tray is in folded or unfolded state) of its delivery tray so that a warning can be issued or the ongoing printing operation can be interrupted, is relatively low in cost. However, it suffers from the following two problems. The first one is that the delivery tray is difficult to operate: the tray must be manually unfolded by an operator after a warning is issued or the ongoing printing operation is interrupted. In particular, in the case in which a printing operation is carried out by a recording apparatus which is located away from an operator and must be remote-controlled, manually unfolding the delivery tray of the recording apparatus becomes an operation which is extremely troublesome (requires time and labor). Secondly, simply interrupting the ongoing printing operation or issuing a warning is insufficient to ensure that an operator will be prompted to unfold the delivery tray, sometimes causing the operator to erroneously think that the recording apparatus main assembly itself is having a problem. 
         [0007]    Further, in the case of a delivery tray which is large in the angle by which it has to be rotated into the unfolded position, there is the problem that a large collisional noise is created at the end of the operation for unfolding the delivery tray. As the means for preventing the occurrence of this large collisional noise, it is possible to provide the delivery tray stopper portion of the recording apparatus main assembly with a shock absorbing member, such a piece of sponge. However, the provision of the shock absorbing member reduces the delivery tray in the positional and attitudinal accuracy, which in turn reduces the recording apparatus in the accuracy with which the recording apparatus records. As another means for reducing the large collisional noise, it is possible to employ an oil-filled damper. However, the employment of an oil-filled damper substantially increases in cost and size a recording apparatus equipped with a foldable delivery tray. 
       SUMMARY OF THE INVENTION 
       [0008]    The primary object of the present invention is to provide a recording apparatus which is optimal in the amount of the moment which its delivery tray gains as the delivery tray is unfolded, the delivery tray of which automatically opens, and which is slower in the speed at which its delivery tray is unfolded, being therefore substantially smaller in the collisional noise which occurs at the end of the unfolding of the delivery tray, than recording apparatuses in accordance with the prior art. 
         [0009]    According to an aspect of the present invention, there is provided a recording apparatus comprising a discharging roller for discharging, from a main assembly of said apparatus, a recording material having been subjected to a recording operation by recording means; an openable and closable sheet discharge tray for supporting the recording material discharged by said discharging roller; locking means for holding said sheet discharge tray at a closed position; drive transmitting means for transmitting a driving force to release said locking means in interrelation with main assembly driving means; and advancing and retracting means for advancing and retracting said drive transmitting means relative to said main assembly driving means in interrelation with a position of said sheet discharge tray, wherein said locking means is effective to release said locking means by said main assembly driving means so as to permit said drive transmitting means to retract away from said main assembly driving means by a weight of said sheet discharge tray and an urging force of urging means when said sheet discharge tray is at the closed position. 
         [0010]    These and other objects, features, and advantages of the present invention will become more apparent upon consideration of the following description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a vertical sectional view of the recording apparatus, in the first preferred embodiment of the present invention, the delivery tray of which is in the unfolded state, showing the general structure of the apparatus. 
           [0012]      FIG. 2  is a vertical sectional view of the delivery tray of the recording apparatus, in the first preferred embodiment of the present invention, which is in the folded state, and the components related to the delivery tray operation. 
           [0013]      FIG. 3  is a vertical sectional view of the delivery tray of the recording apparatus, in the first preferred embodiment of the present invention, which has just begun to be automatically unfolded, and the components related to the tray operation. 
           [0014]      FIG. 4  is a vertical sectional view of the delivery tray of the recording apparatus, in the first preferred embodiment of the present invention, which is being rotated away from the apparatus main assembly about its hinge portion by a pusher spring, and the components related to the tray operation. 
           [0015]      FIG. 5  is a vertical sectional view of the delivery tray of the recording apparatus, in the first preferred embodiment of the present invention, which is being unfolded by its own weight at a slow speed while being subjected to the force which is working in the direction to fold the tray, and the components related to the tray operation. 
           [0016]      FIG. 6  is a vertical sectional view of the delivery tray of the recording apparatus, in the first preferred embodiment of the present invention, which has just automatically and fully unfolded, and the components related to the tray operation. 
           [0017]      FIG. 7  is a graph showing the relationship between the delivery tray angle (tray position during unfolding or folding of tray) and the moment of the delivery tray. 
           [0018]      FIG. 8  is a vertical sectional view of the delivery tray of the recording apparatus, in the first preferred embodiment of the present invention, which is being rotated toward the apparatus main assembly about its hinge portion, that is, in the direction in which it is to be folded, and the components related to the tray operation. 
           [0019]      FIG. 9  is a vertical and partially sectional view of the trigger lever, sheet discharger roller gears, and the adjacencies thereof, showing their states during the rotation of the trigger lever by the sheet discharger roller gear in the counterclockwise direction shown in the drawing. 
           [0020]      FIG. 10  is a vertical and partially sectional view of the trigger lever, sheet discharger roller gears, and the adjacencies thereof, showing their states during the rotation of the trigger lever by the sheet discharger roller gear in the clockwise direction shown in the drawing. 
           [0021]      FIG. 11  is a vertical sectional view of the delivery tray of the recording apparatus, in the second preferred embodiment of the present invention, which is in the folded state, and the components related to the tray operation. 
           [0022]      FIG. 12  is a top plan view of the mechanism for folding or unfolding the delivery tray. 
           [0023]      FIG. 13  is a vertical sectional view of the delivery tray, which is in the halfway unfolded state. 
           [0024]      FIG. 14  is a vertical sectional view of the delivery tray, which is in the fully unfolded state. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiment 1 
       [0025]    Hereinafter, the preferred embodiments of the present invention will be concretely described with reference to the appended drawings. Incidentally, if a given component in one of the drawings is designated with the same referential numerals or characters as those designating a component in another drawing, the two components are identical or correspond to each other. 
         [0026]      FIG. 1  is a vertical sectional view of the recording apparatus in the first preferred embodiment of the present invention, and shows the general structure of the recording apparatus, the delivery tray of which is in the unfolded state.  FIG. 2  is a vertical sectional view of the same recording apparatus as the one shown in  FIG. 2 , except that in  FIG. 2 , the delivery tray of the apparatus is in the folded state. 
         [0027]    The recording apparatus  1  in this embodiment is an ink jet recording apparatus. It is provided with bottom and top frames  10  and  11 , respectively. A portion of the bottom frame  10  and a portion of the top frame  11  make up the external shell (housing) of the recording apparatus  1 . The bottom and top frames  10  and  11  are solidly fixed to each other by their unshown outer edge portions. The recording apparatus  1  is provided with a sheet feeding portion for feeding recording medium, such as recording paper, to the image forming portion. The sheet feeding portion is located behind the rear end of the bottom frame  10 . The sheet feeding portion is provided with: a sheet feeder tray  20 , which can be folded or unfolded; a pressure plate  21  which is movable in an oscillatory manner; a sheet feeder roller  22  which is rotatable; a sheet separator roller  23  which is kept pressed upon the sheet feeder roller  22 , and is rotated by the rotation of the sheet feeder roller  22 ; and a sheet guide  25  provided with a sheet sensor  24 . 
         [0028]    A recording medium S is in the sheet feeder tray  20 ; multiple recording mediums S are stacked in the sheet feeder tray  20 , with the bottommost recording medium S being in contact with the pressure plate  21 . More specifically, as the sheet feeder tray  20  is unfolded, the recording medium bearing surface of the sheet feeder tray  20  becomes roughly flush with the recording medium bearing surface of the pressure plate  21 , which is tilted. Thus, a stack of recording mediums S is placed in the sheet feeder tray  20  so that the bottommost recording medium S comes into contact with both the recording medium bearing surface of the sheet feeder tray  20  and the recording medium bearing surface of the pressure plate  21 . The pressure plate  21  and sheet feeder roller  22  are driven by an unshown sheet feeder roller motor. The position of the pressure plate  21  and the rotation of the sheet feeder roller  22  are controlled by an unshown control cam. The sheet separator roller  23  is provided with an internal torque limiter (unshown) so that the sheet separator roller  23  rotates only when the amount of torque to which it is being subjected is greater than a preset value. 
         [0029]    The recording apparatus  1  is also provided with: a recording head  40  which makes up the image forming portion; and a platen  32 . The recording head  40  and platen  32  are located roughly in the center portion of the bottom frame  10 . The recording head  40  makes up the recording means which records an image on the recording medium S, based on picture information. The platen  32  is positioned so that it opposes the recording head  40 . It is a component which guides and supports the recording medium S so that the recording medium S directly faces the recording head  40 . Further, the recording apparatus  1  is provided with a sheet conveyer roller  30 , a pinch roller  31 , and a sheet guide  25 . In terms of the recording medium conveyance direction, the sheet conveyer roller  30  and pinch roller  31  are on the upstream side of the platen  32 , and on the downstream side of the sheet guide  25 . The pinch roller  31  is kept pressed upon the sheet conveyer roller  30  and is rotated by the rotation of the sheet conveyer roller  30 . The recording apparatus  1  is also provided with a pair of spur-like wheels  34 , which are on the downstream side of the platen  32 . The spur-like wheel  34  is kept pressed upon the corresponding sheet discharger roller of a pair of sheet discharger rollers, and is rotatable by the rotation of the sheet discharger roller. The sheet discharger rollers  33  and spur-like wheels  34  make up a discharging means for discharging the recording medium S from the apparatus main assembly. 
         [0030]    The recording head  40  is mounted on a carriage  41  which is movable above the platen  32  in the direction (primary scan direction) parallel to the width direction of the recording medium S. The carriage  41  is supported by a guide shaft  42  and a guide rail  11   a,  which are parallel to the shaft of the sheet conveyer roller  30  and the shaft of the sheet discharger roller  33 , in such a manner that it can be reciprocally movable along the guide shaft  42  and guide rail  11   a.  The guide rail  11   a  is integral with the top frame  11 . The carriage  41  is driven by a carriage motor  34  as the carriage driving force source, through a timing belt  44  suspended by an unshown motor pulley and an unshown idler pulley. The recording head  40  is in connection with an unshown FFC (flexible flat cable) for transmitting signals and electric power between the apparatus main assembly and recording head substrate. 
         [0031]    This recording apparatus is structured to record an image by jetting ink from the ink jetting orifices of the recording head  40 , onto the recording medium S, based on picture information. The ink jet recording head  40  in this embodiment selectively drives the heaters located inward of the ink jetting orifices to jet ink droplets. More specifically, as each of the selected heaters is heated, the body of ink in the corresponding ink jetting orifice is boiled by the heat. More specifically, bubbles grow and collapse, changing therefore the internal pressure in the orifice. This pressure change is utilized to jet ink droplets from the orifice. The recording head  40  is in connection with an ink container, which is removably attached to the recording head  40 . 
         [0032]    The sheet conveyer roller  30  and sheet discharger rollers  33  are synchronously driven by a sheet conveyance motor  37 . The sheet conveyer roller  30  is provided with a sheet conveyer roller gear  35 , which is solidly attached to one of the lengthwise ends of the shaft of the sheet conveyer roller  30 . The sheet discharger roller  33  is provided with a sheet discharger roller gear  36 , which is solidly attached to one of the lengthwise ends of the shaft of the sheet discharger roller  33 . The sheet discharger roller gear  36  is provided with a gear portion  36   a  and a cam portion  36   b.  The sheet conveyer roller gear  35  and the gear portion  36   b  of the sheet discharger roller gear  36  are in connection with each other through a transmission gear  39 . The sheet conveyance motor  37  and sheet conveyer roller gear  35  are in connection with each other through a sheet conveyer belt  38  suspended by the pulleys, so that driving force can be transmitted from the sheet conveyance motor  37  to the sheet conveyer roller gear  35 . Thus, as driving force is transmitted to the sheet conveyer roller gear  35  through the sheet conveyer belt  38 , the sheet conveyer roller  30  is rotationally driven. At the same time, the rotation of the sheet conveyer roller gear  35  is transmitted to the sheet discharger roller gear  36  through the transmission gear  39  and gear portion  36   a.  Thus, as driving force is transmitted to the sheet conveyer roller gear  35 , the sheet discharger roller  33  is also rotationally driven in synchronism with the sheet conveyer roller  30 . 
         [0033]    Next, referring to  FIG. 1 , the operation of the recording apparatus  1  will be described. As a record start command is issued, the pressure plate  21  is oscillated by the unshown sheet feeder motor. As a result, the stack of recording mediums S in the sheet feeder tray is pressed upon the sheet feeder roller  22 . Thus, several recording mediums S on the sheet feeder roller  22  side are sent out from the sheet feeder tray by the rotation of the sheet feeder roller  22 . However, the recording mediums S other than the topmost recording medium S are held up by the sheet separator roller  23  which is provided with the torque limiter. Thus, only the topmost recording medium S is conveyed further along the sheet guide  25 . Thereafter, the pressure plate  21  is retracted far enough to keep the stack of recording mediums S in the sheet feeder tray separated from the sheet feeder roller  22 , and the recording mediums S which were held up by the separator roller  23  are returned to the original location in the sheet feeder tray by an unshown sheet return lever. 
         [0034]    Meanwhile, the recording medium S which was sent out along the sheet guide  25  is conveyed further by the rotation of the sheet feeder roller  22  and sheet separator roller  23 , and collides into the nip between the sheet conveyer roller  30  and a pinch roller  31 , which are remaining stationary. As a result, the recording medium S is made to curve by a preset amount. Thus, the entirety of the leading edge of the recording medium S is placed in contact with the nip by the resiliency of the recording medium S; in other words, the recording medium S is properly aligned. Then, as soon as it is determined, based on the information from the sheet sensor  24 , that the recording medium S was conveyed by a preset distance, the sheet conveyer roller  30  begins to be rotationally driven by the sheet conveyance motor  37 . The preceding steps described above can correctly position the recording medium S, even if the recording medium S was being conveyed askew. Thereafter, the transmission of driving force to the sheet feeder roller  22  is stopped, and the separator roller  23  is separated from the sheet feeder roller  22 . This separation of the separator roller  23  from the sheet feeder roller  22  reduces the excessive amount of forward pressure to which the recording medium S is being subjected while being held by the abovementioned nip. Therefore, the recording medium S is conveyed with a higher level of precision. 
         [0035]    After the recording medium S is conveyed a preset distance along the platen  32 , it is stopped so that the leading edge of the recording medium S aligns with the image formation position (recording start position) on the platen  32 . Then, the carriage  41  is driven by the carriage motor  43  so that the recording head  40  is moved in the primary scan direction while being driven to jet ink from its ink jetting orifices onto the recording medium S, based on picture information. As a result, recording is made by the amount equivalent to a single line, that is, a portion of the intended image, which corresponds to the length of each column of ink jetting orifices of the ink jet recording head. Then, the recording medium S is conveyed by a preset distance (pitch) in the secondary scan direction. The process of recording a portion of the intended image, which corresponds to a single primary scanning line, and the process of conveying the recording medium S in the secondary scan direction, are alternately repeated until the intended image is completed on the recording medium S. After being moved past the platen  32 , the recording medium S is pinched between the sheet conveyer roller  30  and the sheet discharger roller  33 , which are being synchronously driven, and is discharged from the apparatus main assembly. While the image is being formed, the presence of the trailing edge of the recording medium edge is also detected by the sheet sensor  24  so that recording can be continued until the time of the arrival of the trailing edge of the recording medium S at the image formation position, which can be calculated based on the result of the detection by the sheet sensor  24 . 
         [0036]    Next, referring to  FIGS. 1 and 2 , the structure of the mechanism for unfolding or folding the delivery tray of the recording apparatus  1  will be described. A delivery tray  50  into which recording mediums S are accumulated as they are discharged from the apparatus main assembly is attached to the front side of the apparatus main assembly. More specifically, the delivery tray  50  is provided with a pair of shafts  50   a,  which are located at the left and right ends of the tray  50 , one for one, whereas the apparatus main assembly is provided with a pair of bearings  10   a,  which are located at the bottom front ends of the apparatus main assembly, one for one. Thus, as the delivery tray  50  is attached to the apparatus main assembly by fitting the pair of shafts  50   a  into the pair of bearings  10   a,  one for one, the delivery tray  50  can be rotationally folded or unfolded relative to the apparatus main assembly. One of the lateral walls of the delivery tray  50  is provided with an arcuate slot  50   b  with a preset length (preset angular range), the center of which coincides with the axial line of the shaft  50   a.  On the other hand, the lateral wall of the bottom frame  10 , which corresponds to the lateral wall of the delivery tray  50  having the slot  50   b,  is provided with a projection  10   b,  which fits into the slot  50   a  of the delivery tray  50  so that the projection  10   b  can slide from one end of the slot  50   a  to the other. Thus, as the projection  10   b  of the bottom frame  10  is fitted into the arcuate slot  50   a  of the delivery tray  50 , the delivery tray  50  can be rotationally moved between its folded position, or the virtually upright position, shown in  FIG. 2 , and its unfolded position, or the slight angled position relative to the horizontal direction, shown in  FIG. 1 . 
         [0037]    When the delivery tray  50  is in the unfolded position shown in  FIG. 1 , the recording mediums can be discharged from the apparatus main assembly into the delivery tray  50  so that they accumulate on the combination of the sheet supporting surface portion  10   c  of the bottom frame  10  and the sheet supporting surface of the delivery tray  50 . The abovementioned lateral wall of the delivery tray  50  is provided with a cam portion  50   c  and a hook portion  50   d,  which are outside the space in which the recording mediums are accumulated. Incidentally, in this embodiment, the cam portion  36   b  of the sheet discharger roller gear  36  solidly attached to the sheet discharger roller  33  will be referred to as first cam portion, and the cam portion  50   c  of the delivery tray  50  will be referred to as third cam portion. Further, the hook portion  50   d  will be referred to as second cam portion. The end of the delivery tray  50  is provided with a handhold portion  50   e.    
         [0038]    The rear end portion of the apparatus main assembly is provided with a primary lever  60 , which is outside the space in which recording mediums are accumulated. The primary lever  60  is supported by its shaft portion  60   b  by the top frame  11  so that the primary lever  60  can be rotationally moved about the axial line of the shaft portion  60   b.  Further, the primary lever  60  is kept pressured in the counterclockwise direction, shown in the drawing, by a spring  61 . The primary lever  60  makes up the driving force transmitting means, which will be described later. The primary lever  60  is provided with a roller  62 , which is rotatably attached to the front end of the primary lever  60  by its shaft. The roller  62  functions as a cam follower, which follows the cam portion  50   c  (third cam portion) of the delivery tray  50  while rolling on the cam portion  50   c.  The roller  62  remains in contact with the cam portion  50   c  of the delivery tray  50 . It is enabled to follow the cam portion  50   c  of the delivery tray  50  while rolling on the cam portion  50   c  as the delivery tray  50  is unfolded or folded. The cam portion  50   c  of the delivery tray  50  and the roller  62  of the primary lever  60  make up the means for moving forward or backward the primary lever  60  and trigger lever  63 , which will be described later. 
         [0039]    The primary lever  60  is also provided with a trigger lever  63 , which is attached to the opposite end of the primary lever  60  from the roller  62 . The trigger lever  63  is rotationally movable about the shaft portion  60   c  of the primary lever  60 . The trigger lever  63  is kept pressured by a spring  64  so that it remains at the center of the range of its rotational movement. That is, the resiliency of the spring  64  is strong enough to keep the trigger lever  63  at the center of the range in which the trigger lever  63  is rotationally movable. More specifically, referring to  FIGS. 2-5 , the dimension of the range (rotational angle) in which the trigger lever  63  is rotationally movable is determined by the engagement between the projection  60   i  of the primary lever  60  and the arcuate slot  63   b  of the trigger lever  63 . Further, the spring  64  is made and positioned so that its ends engage with both the projection  63   c  of the trigger lever  63  and the projection  60   i  of the primary lever  60 . Thus, as the trigger lever  63  is rotationally displaced by the cam portion  36   b,  the spring  64  is elastically deformed, and then, the primary lever  60  is rotationally displaced. This rotational displacement of the primary lever  60  causes the hook portion  50   d  to disengage from the hook catching portion  60   a  (delivery tray becomes unlocked), which will be described later. In this embodiment, the trigger lever  6   3 , with which the primary lever  60  as the driving force transmitting means is provided makes up the cam follower portion which follows the cam portion  36   b  (first cam portion) of the sheet discharger roller gear  36  of the sheet discharger roller  33  as the driving means on the apparatus main assembly side. 
         [0040]    The primary lever  60  is also provided with a pusher spring  65 , which is attached to the front end of the primary lever  60 . The pusher spring  65  is a tortional coil spring, and is attached to the primary lever  60  so that it can rotationally move. One end of the pusher spring  65  projects frontward as an elastic arm. More specifically, the pusher spring  65  is attached to the shaft portion  60   e  of the primary lever  60 , being thereby enabled to rotationally move. The pusher spring  65  is made and position so that one of its arm portions is enabled to contact the projection  60   e  of the primary lever  60 , and the other is enabled to contact the back surface of the delivery tray  50 . When the delivery tray  50  is in the folded position ( FIG. 2 ), the second arm portion is between the delivery tray  50  and the primary lever  60 , being thereby chargeable (elastically deformable by application of pressure). 
         [0041]    Further, the front end of the primary lever  60  is provided with a hook catching portion  60   a,  which can be engaged with the hook portion  50   d,  which is on the back surface of the delivery tray  50 . As the delivery tray  50  is folded, this hook catching portion  60   a  engages with the hook portion  50   d,  and while the delivery tray  50  is in the folded position, the hook catching portion  60   a  remains engaged with the hook portion  50   d,  continuing to apply the force from the spring  61  attached to the primary lever  60 , to the delivery tray  50 . Therefore, while the delivery tray  50  is in the folded position, it is provided with such a moment that acts in the direction to rotate the delivery tray  50  in the clockwise direction shown in the drawing, about the shaft portion  10   a,  and therefore, the delivery tray  50  remains folded after it is moved into the folded position. That is, the hook catching portion  60   a  of the primary lever  60 , which is provided, by the spring  61 , with the moment which acts in the direction to cause the primary lever  60  in the counterclockwise direction, is engaged with the hook portion  50   d  of the delivery tray  50 . In other words, the spring  61 , hook catching portion  60   a,  and hook portion  50   d  make up the locking means for keeping the delivery tray  50  in the folded position (keeping delivery tray  50  locked to apparatus main assembly). 
         [0042]      FIG. 3  is a vertical sectional view of the delivery tray  50  and the components related to the operation of the delivery tray  50 , showing the state of the delivery tray  50  and the components before the starting of the operation for automatically unfolding the delivery tray  50 .  FIG. 4  is a vertical sectional view of the delivery tray  50  and the components related to the operation of the delivery tray  50 , showing the state in which the delivery tray  50  and the components are while the delivery tray  50  is rotationally pushed away from the apparatus main assembly by the pusher spring  65 .  FIG. 5  is a vertical sectional view of the delivery tray  50  and the components related to the operation of the delivery tray  50 , showing the state in which the delivery tray  50  and the components are while the delivery tray  50  is unfolded at a slower speed by its own weight alone while remaining under the pressure (moment) which acts in the direction to fold the delivery tray  50 .  FIG. 6  is a vertical sectional view of the delivery tray  50  and the components related to the operation of the delivery tray  50 , showing the state in which the delivery tray  50  and the components are after the unfolding of the delivery tray  50 .  FIG. 7  is a graph showing the characteristic of the moment with which the delivery tray  50  is provided while the delivery tray  50  is automatically unfolded, or folded, that is, the relationship between the angle of the delivery tray  50  and the amount of the moment to which the delivery tray  50  is provided while the delivery tray  50  was automatically unfolded, or folded. 
         [0043]    Next, referring to  FIGS. 1-7 , the steps through which the delivery tray  50  is automatically unfolded will be described. As a recording start command is issued when the delivery tray  50  is in the folded position, the aforementioned operation for feeding recording mediums, and operation for properly positioning the recording mediums which are being conveyed askew, are started. Then, after the completion of these two operations, the driving of the sheet conveyance motor  37  is started. Thus, the sheet conveyer roller  30  and sheet discharger roller  33  are rotationally driven by the sheet conveyance motor  37  as the driving force source. As a result, the sheet discharger roller gear  36 , which is integral with the sheet discharger roller  33 , is rotationally driven ( FIG. 3 ). As the sheet discharger roller gear  36  rotates, the cam portion  36   b  (first cam portion) of the sheet discharger roller gear  36  presses the tip portion of the trigger lever  63 , which is the cam follower portion of the trigger lever  63 . As a result, the trigger lever  63  is pushed downward. Thus, the trigger lever  63  rotates into the position in which it begins to rotate the primary lever  60  in the clockwise direction against the force from the spring  61 ; in other words, the trigger lever  63  is rotated into the position, beyond which it rotates the primary lever  60  in the direction to elastically deform the spring  61 , as shown in  FIG. 3 . 
         [0044]    Thus, as the sheet discharger roller gear  36  is further rotated, the tip portion of the trigger lever  63  moves onto the functional surface (peripheral surface) of the cam portion  36   b  while the trigger lever  63  is rotationally displaced in the clockwise direction, as shown in  FIG. 4 . This rotational displacement of the trigger lever  63  in the clockwise direction causes the hook catching portion  60   a  to disengage from the hook portion  50   d,  and then, the front arm portion of the pusher spring  65  which is in the elastically deformed state pushes the hook portion  50   d  outward. As a result, the delivery tray  50  is rotationally pushed away from the apparatus main assembly, into the position shown in  FIG. 4 . Incidentally, if there are obstacles in front of the delivery tray  50  and/or delivery tray  50  is held, the arm portion of the pusher spring  65  absorbs external force by elastically deforming. Therefore, the components, such as the primary lever  60 , which make up the mechanism for folding or unfolding the delivery tray  50 , are not damaged. The primary lever  60  and trigger lever  63  make up the driving force transmitting means which unlocks the locking means  60   a  and  50   d  by being moved by the rotational movement of the sheet discharger roller gear  36 . 
         [0045]    As the delivery tray  50  is pushed outward into the position (angle) shown in  FIG. 4 , the center of gravity G of the delivery tray  50  shifts frontward of the axial line of the shaft portion  50   a,  which coincides with the rotational axis of the delivery tray  50 . Thus, the delivery tray  50  is rotated by the moment provided by its own weight in the unfolding direction to the position ( FIG. 5 ) where the cam portion  50   c  comes into contact with the roller  62  (cam follower portion). Then, the delivery tray  50  is further rotated by the moment provided by its own weight, with the roller  62  rolling on the cam portion  50   c,  until it reaches the position (unfolded position) shown in  FIG. 6 . During this rotational movement of the delivery tray  50 , the roller  62  rolls on the cam portion  50   c,  and the primary lever  60  is rotationally moved further in the direction (clockwise direction shown in drawing) to elastically deform the spring  61  ( FIG. 6 ). As the spring  61  is elastically deformed, the force which is applied to the delivery tray  50  in the direction to fold the delivery tray  50  by the spring  61  increases. The amount of this force is smaller than the amount of moment provided by the weight of the delivery tray  50  itself. However, the mechanism for folding or unfolding the delivery tray  50  is designed so that as the delivery tray  50  is rotationally moved in the unfolding direction, this force which acts on the delivery tray  50  in the direction to fold the delivery tray  50  increases in a manner to follow a preset curve. This will be described later in detail. 
         [0046]    Further, during this period, the delivery tray  50  is rotated by the moment provided by its own weight, causing the primary lever  60  and trigger lever  63  to rotate in the clockwise direction indicated by the arrow mark in the drawings, through the cam portion  50   c  (third cam portion) and roller  62 . As a result, the trigger lever  63  separates from the cam portion  36   b  (first cam portion) of the sheet discharger roller gear  36 , as shown in  FIG. 6 . The cam portion  50   c  of the delivery tray  50  and the roller  62  of the primary lever  60  make up the means for moving forward or backward the primary lever  60  and trigger lever  63 , which make up the driving force transmitting means, relative to the sheet discharger roller gear  36  which is the driving means on the apparatus main assembly side. 
         [0047]    Further, in this embodiment, the mechanism for rotationally moving (folding or unfolding) the delivery tray  50  is structured so that when the delivery tray  50  is in the folded position, the locking means (hook catching means  60   a  and hook portion  50   d ) is unlocked by the sheet discharger roller gear  36 . Further, it is structured so that the primary lever  60  and trigger lever  63  are moved away from the sheet discharger roller gear  36  by the rotational movement of the delivery tray  50 . The above described process in which the delivery tray  50  automatically unfolds ends before the recording medium S is conveyed to the image formation position on the platen  32 . Therefore, the variation in the torque, vibrations, etc., which occur while recording is made do not adversely affect the operation for automatically unfolding the delivery tray  50 . 
         [0048]    Shown in  FIG. 7  is the moment with which the delivery tray  50  is provided in the operation for automatically unfolding the delivery tray  50 . In  FIG. 7 , the horizontal axis represents the angle of the delivery tray  50 , and the vertical axis represents the amount of the moment, with respect to the rotational axis  50   a,  with which the delivery tray  50  is provided. The fine line represents the amount of moment with which the delivery tray  50  is provided by its own weight (which hereafter may be referred to as self-weight moment). The thick grey line represents the amount of the additional moment with which the delivery tray  50  is provided by the delivery tray moving (folding or unfolding) mechanism, made up of the primary lever  60 , etc. Further, the thick black line represents the total amount of moment, that is, the sum of (difference between) the self-weight moment and additional moment. 
         [0049]    First, the self-weight moment, which is represented by the fine line, will be described. When the delivery tray  50  is in the folded position, the center of gravity G of the delivery tray  50  is slightly behind the rotational axis of the shaft portion  50   a.  Therefore, the self-weight moment acts in the direction to keep the delivery tray  50  folded, and is very small. As the operation for automatically unfolding the delivery tray  50  begins, the delivery tray  50  is rotationally pushed away from the apparatus main assembly by the pusher spring  65 . When the delivery tray  50  is in the position shown in  FIG. 4 , the self-weight moment with respect to the shaft portion  50   a  is opposite in direction from when the delivery tray  50  is in the folded position; the self-weight moment acts in the direction to unfold the delivery tray  50 . As the attitude of the delivery tray  50  further changes in the direction to unfold, the position of the center of gravity G further moves frontward away from the rotational axis of the delivery tray  50 . Therefore, as the delivery tray  50  further unfolds, the self-weight moment keeps on increasing in a manner of following the so-called “sign curve (sinusoidal curve)”, until the delivery tray  50  completely unfolds. 
         [0050]    Next, the external force, which is represented by the thick grey line, will be described. When the delivery tray  50  is in the folded state, it remains locked in place by the moment with which the delivery tray  50  is provided by the pressure applied to the hook portion  50   d  (second cam portion) by the spring  61  of the primary lever  60  through the hook catching portion  60   a,  and which acts in the direction to fold the tray  50 ; the amount of this moment has a value of “a”. As the operation for automatically opening the delivery tray  50  is started, the pressure is eliminated from the hook catching portion  60   a  by the interaction between the cam portion  36   b  (first cam portion) of the sheet discharger roller gear  36  and the trigger lever  63 . Thus, the external force which acts on the delivery tray  50  is only the force generated by the pusher spring  65  in the direction to move the delivery tray  50  away from the apparatus main assembly, and this force has a very small value of “b”. Then, as the delivery tray  50  is rotationally pushed away slightly from the apparatus main assembly by the pusher spring  65 , that is, when the delivery tray  50  is in the position shown in  FIG. 4 , a small amount of external force, the value of which is “c”, is applied to the delivery tray  50  by the pusher spring  65  in the direction to unfold the delivery tray  50 . Then, the moment the delivery tray  50  separates from the pusher spring  65 , the external force becomes zero. 
         [0051]    Then, as the delivery tray  50  is rotationally unfolded into the mid position, shown in  FIG. 5 , by the self-weight moment, the cam portion  50   c  (third cam portion) of the delivery tray  50  comes into contact with the roller  62  of the primary lever  60 , and begins to be pressed by the roller  62 . As the cam portion  50   c  comes into contact with the roller  62 , the delivery tray  50  begins to be subjected to the external force which acts in the direction to fold the delivery tray  50 , and the value of which is “d”. As the attitude of the delivery tray  50  changes in the direction to unfold the delivery tray  50 , this external force which acts in the direction to fold the delivery tray continues to increase after the contact between the cam portion  50   c  and the roller  62  of the primary lever  60 , as shown in  FIG. 7 . The amount of the external force which acts on the delivery tray  50  in the direction to fold the delivery tray  50  when the delivery tray  50  is in the completely unfolded state has a value of “e”. 
         [0052]    Next, the overall amount of the moment with which the delivery tray  50  is provided, and which is represented by the thick black line will be described. Ignoring the resistance such as frictional resistance, the overall amount of moment means the actual amount of moment with which the delivery tray  50  is provided. When the delivery tray  50  is in the folded state, the overall amount of moment has a value large enough to keep the delivery tray  50  in the folded state. As the operation for unfolding the delivery tray  50  is started, the direction in which the overall amount of moment acts on the delivery tray  50  reverses from the direction to fold the delivery tray  50  to the direction to unfold the delivery tray  50 . Then, until the delivery tray  50  rotates to the position, shown in  FIG. 4 , beyond which the weight of the delivery tray  50  itself is sufficient to rotate the delivery tray  50  in the direction to unfold the delivery tray  50 , the overall moment keeps on acting in the direction to unfold the delivery tray  50 , and has a value sufficient to rotate the delivery tray  50  in the unfolding direction. 
         [0053]    While the delivery tray  50  is in the transitional state between the state shown in  FIG. 4  and the state shown in  FIG. 5 , the overall moment is equal to the self-weight moment that acts in the direction to unfold the delivery tray  50 , and its value gradually increases. While the delivery tray  50  is in the transitional state between the state shown in  FIG. 5  and the completely unfolded state shown in  FIG. 1 , the overall moment with which the delivery tray  50  is provided is the difference between the self-weight moment and the external force, being therefore such a moment that acts in the direction to unfold the delivery tray  50 . Therefore, it is roughly stable and has a very small value of “f”. That is, the mechanism for rotationally moving (unfolding or folding) the delivery tray  50  is structured so that the rotational speed of the delivery tray  50  is adjusted by applying to the delivery tray  50  a rotational force, the amount of which corresponds to the change in the attitude of the delivery tray  50 , with the use of the cam portion  50   c  of the delivery tray  50  and the roller  62  of the primary lever  60 . Incidentally, when the delivery tray  50  is in the completely folded state and completely unfolded state, the delivery tray  50  is subjected to the regulatory force generated by the slot  50   b  and projection  10   b.  Therefore, the value of the moment which acts on the delivery tray  50  is “0”, and therefore, the delivery tray  50  remains stationary. 
         [0054]    In the case of this embodiment described above, not only does the delivery tray  50  automatically and smoothly unfold, but also, at a slower speed than the delivery tray  50  in accordance with the prior art, being therefore substantially smaller in the amount of the impact which occurs at the end of the unfolding of the delivery tray  50 , and the noises resulting from the impact. Further, when the delivery tray  50  is in the folded state, the trigger lever  63  is not in contact with the first cam portion  36   b  of the sheet discharger roller gear  36 . Therefore, even if the sheet discharger roller gear  36  is rotated in response to a recording start command issued when the delivery tray  50  is in the unfolded state, the sheet discharger roller gear  36  and trigger lever  63  do not come into contact with each other, and therefore, the delivery tray  50  remains stationary (delivery tray does not change in status). Further, the delivery tray  50  can be easily unfolded or folded as necessary simply by grasping the handhold portion  50   e  of the delivery tray  50 . 
         [0055]      FIG. 8  is a vertical sectional view of the delivery tray  50  and the components related to the unfolding and folding of the delivery tray  50 , which are in the state in which the delivery tray  50  is being folded.  FIG. 9  is a vertical and partially sectional view of the trigger lever  63 , sheet discharger roller gear  36 , and the adjacencies thereof, which are in the state in which the trigger lever  63  is being rotated in the counterclockwise direction, shown in the drawing, by the sheet discharger roller gear  36 .  FIG. 10  is a vertical and partially sectional view of the trigger lever  63 , sheet discharger roller gear  36 , and the adjacencies thereof, which are in the state in which the trigger lever  63  is being rotated in the clockwise direction, shown in the drawing, by the sheet discharger roller gear  36 . Referring to  FIGS. 8-10 , the trigger lever  63  sometimes comes into contact with the edge of the contact surface of the cam portion  36   b  of the sheet discharger roller gear  36  as shown in  FIG. 8  (when cam portion  36   b  of sheet discharger roller gear  36  is at a specific location). In the case of this embodiment, it is unpredictable whether the trigger lever  63  will rotate in the direction shown in  FIG. 9  or  10  in the abovementioned situation. Regardless of the direction in which the trigger lever  63  rotates, the primary lever  60  is provided with a moment which acts in the direction to rotate the primary lever  60  in the clockwise direction, shown in the drawing, about the shaft portion  50   a.  Therefore, regardless of the direction in which the trigger lever  63  rotates in the abovementioned situation, the problem that the unfolding or folding of the delivery tray  50  is interfered with, by the abovementioned manner of contact between the sheet discharger roller gear  36  and trigger lever  63  does not occur: for example, the abovementioned manner of contact between the sheet discharger roller gear  36  and trigger lever  63  does not cause the delivery tray  50  to be unsatisfactorily unfolded or folded. 
         [0056]    Also in this embodiment, the sheet discharger roller gear  36  is provided with the cam portions  36   b  having multiple sections which are distributed with equal intervals in the circumferential direction of the sheet discharger roller gear  36 . Therefore, if the sheet discharger roller gear  36  rotates in response to a recording start signal issued while the delivery tray  50  is in the folded state, and the trigger lever  63  is on the functional surface of one of multiple sections of the cam portions  36   b  as shown in  FIG. 9 , the mechanism for unfolding or folding the delivery tray  50  reacts in the following manner. That is, first, as the sheet discharger roller gear  36  rotates, the tip portion of the trigger lever  63  is freed from the cam portion  36   b  with which it has been in contact, by the arrival of the interval between the section of the cam portion  36   b,  with which the trigger portion  63  has been in contact, and the next section of the cam portion  36   b.  Then, as the tip portion of the trigger lever  63  becomes free, the trigger lever  63  is temporarily returned to the center position shown in  FIG. 2 , and then, the operation for automatically unfolding the delivery tray  50  is continued. As described above, the sheet discharger roller gear  36  is provided with the cam portions  36   b  having multiple sections which are distributed with equal intervals in the circumferential direction of the sheet discharger roller gear  36 . Therefore, the operation for automatically unfolding the delivery tray  50  can be completed before the recording medium S is delivered to the image formation position on the platen  32 . Therefore, the operation for automatically unfolding the delivery tray  50  is not adversely affected by the variation in torque and/or vibrations resulting from a recording operation. 
         [0057]    Also in this embodiment, as an operator moves the delivery tray  50  in the direction to unfold the delivery tray  50 , by holding the handhold portion  50  of the delivery tray  50 , the primary lever  60  is rotated in the clockwise direction, shown in the drawing, by the moment with which the primary lever  60  is provided by this initial action in the delivery tray unfolding operation. As a result, the hook catching portion  60   a  is disengaged from the hook portion  50   d.    
         [0058]    Also in this embodiment described above, the mechanism for automatically and rotationally moving (folding or unfolding) the delivery tray  50  is not provided with a drive force source dedicated therefor, and also, is not specifically driven for unfolding or folding the delivery tray  50 . In other words, the driving force source (sheet conveyance motor, or the like) necessary for the apparatus main assembly to carry out a recording operation, and the sheet driving means (sheet conveyer roller  30 , sheet discharger roller  33 , etc.) are utilized to carry out the operation for automatically unfolding the delivery tray  50 . 
       Embodiment 2 
       [0059]    Next, referring to  FIGS. 11-14 , the second preferred embodiment of the present invention will be described.  FIG. 11  is a vertical sectional view of the recording apparatus in the second embodiment of the present invention, the delivery tray of which is in the folded state.  FIG. 12  is a top plan view of the mechanism for unfolding and unfolding the delivery tray.  FIG. 13  is a vertical sectional view of the delivery tray which is being unfolded, and the components related to the operation of the delivery tray.  FIG. 14  is a vertical sectional view of the delivery tray which is in the completely unfolded state, and the components relate to the operation of the delivery tray. The center of gravity G of the delivery tray  50  in this embodiment is on the frontward side of the center of gravity G of the delivery tray  50  in the first embodiment. In this embodiment, therefore, the moment of the delivery tray  50  attributable to the weight of the delivery tray  50  itself acts in the direction to unfold the delivery tray  50  even when the delivery tray  50  is in the completely unfolded state. In the case of a structural arrangement such as this one, it is unnecessary to push the delivery tray  50  away from the apparatus main assembly during the operation for automatically unfolding the delivery tray  50 . That is, all that is necessary to initiate the operation for automatically unfolding the delivery tray  50  is to unlock the delivery tray  50  from the apparatus main assembly. In other words, a component equivalent to the pusher spring  65  in the first embodiment is unnecessary. 
         [0060]    In the first embodiment, when the delivery tray  50  is in the completely folded state, the delivery tray  50  was kept held to the apparatus main assembly by keeping the hook portion  50   d  of the delivery tray  50  engaged with the hook catching portion  60   a  of the primary lever  60  by utilizing the force generated by the spring  61 . In comparison, in this embodiment, when the delivery tray  50  is in the completely folded state, the delivery tray  50  is kept held to the apparatus main assembly by keeping the roller  62  of the primary lever  60  in contact with the tray locking slant surface portion  50   g  of the delivery tray  50 , as shown in  FIG. 11 . Further, the primary lever  60  in this embodiment is provided with an arm portion  60   g  having a slant surface  60   h,  instead of the trigger lever  63  in the first embodiment. This arm portion  60   g  extends rearward so that it can be engaged with the bottom surface of the carriage  41 , as shown in the drawing. 
         [0061]    Thus, as the carriage  41  is moved to the end of the moving range of the carriage  41 , which is on the side of the mechanism for unfolding or folding the delivery tray, that is, the position indicated by a double-dot chain line in  FIG. 12 , the slanted surface of the arm portion  60   a  is pressed by the carriage  41 . Therefore, the primary lever  60  is rotationally moved in the clockwise direction, shown in the drawing, about the shaft portion  60   a.  Therefore, the roller  62  of the lever  60  moves upward as shown in  FIG. 13 . The carriage  41  has a regulatory function similar to the regulatory function of the cam portion  36   b  (first cam portion) of the sheet discharger roller gear  36  in the first embodiment, and the arm portion  60   b  functions as the cam follower which follows the bottom surface of the carriage  41  which functions as a cam. As the roller  62  moves upward, the delivery tray  50  becomes unlocked from the apparatus main assembly, being thereby allowed to be rotated by its own weight to the midway point shown  FIG. 13 . As the delivery tray  50  moves into the position shown in  FIG. 13 , the cam portion  50   c  (second cam portion) of the delivery tray  50  comes into contact with the roller  62 . In this embodiment, the locking means for keeping the delivery tray  50  in the completely folded state is made up of the delivery tray locking slanted surface portion  50   g  and the roller  62 . Further, the primary lever  60  makes up the driving force transmitting means which is moved by the movement of the carriage  41 , as the driving means on the apparatus main assembly side, to disengage the delivery tray locking means made up of the delivery tray locking slanted surface portion  50   g  and roller  62 . 
         [0062]    As the cam portion  50   c  comes into contact with the roller  62 , the delivery tray  50  rotates further in the unfolding direction due to its own weight, as in the first embodiment, until it becomes completely unfolded as shown in  FIG. 14 . While the state of the delivery tray  50  changes from the state shown in  FIG. 13  to the completely unfolded state shown in  FIG. 14 , the roller  62  rolls on the cam portion  50   c,  and the primary lever  60  is rotationally moved in the direction to resiliently deform the spring  61  (clockwise direction shown in drawing), as in the first embodiment. That is, the delivery tray  50  is rotationally moved in the unfolding direction at a gentle speed by the difference between the self-weight moment of the delivery tray  50  and the external force attributable to the spring  61 , while rotating the primary lever  60  in the direction to elastically deforming the spring  61 . Thus, the moment which acts on the delivery tray  50  in the direction to fold the delivery tray  50  continuously increases until the delivery tray  50  is completely unfolded. 
         [0063]    Further, while the delivery tray  50  is rotated from the position shown in  FIG. 13  to the position shown in  FIG. 14 , the primary lever  60  is rotated in the clockwise direction, shown in the drawing, by the self-weight moment of the delivery tray  50  through the cam portion  50   c.  Therefore, the arm portion  60   g  retracts from the moving range of the carriage  41  (in particular, section in which arm portion  60   g  can engage with carriage  41 ). That is, also in this embodiment, the cam portion  50   c  of the delivery tray  50  and the roller  62  of the primary lever  60  make up the means for advancing or retracting the primary lever  60 , which is the driving force transmitting means, relative to the carriage  41 , which is the driving means on the apparatus main assembly side, in response to the change in the attitude of the delivery tray  50 . Further, the mechanism for rotationally moving (unfolding or folding) the delivery tray  50  is structured so that when the delivery tray  50  is in the folded state, the locking means (delivery tray locking slanted surface portion  50   g  and roller  62 ) is disengaged from the delivery tray  50  by the carriage  41 , and also, so that the primary lever  60  is moved away from the carriage  41  by the movement of the delivery tray  50 . Further, the mechanism is structured so that the rotational speed of the delivery tray  50  is adjusted by countering the moment of the delivery tray  50 , which is affected by the change in the attitude of the delivery tray  50 , with the external force which the interaction between the cam portion  50   c  of the delivery tray  50  and the roller  62  of the primary lever  60  generates. 
         [0064]    Except for the features described above, the means for unfolding or folding the delivery tray, in the second embodiment, is practically the same in structure and function as that in the first embodiment. Therefore, the second embodiment also can optimize the amount of the moment with which the delivery tray  50  is provided while the delivery tray  50  is unfolded, as can the first embodiment. That is, compared to the delivery tray controlling means in accordance with the prior art, the delivery tray controlling means in the second embodiment also can substantially reduce the speed at which the delivery tray  50  automatically unfolds, and therefore, can substantially reduce the amount of the impact which occurs at the end of the unfolding of the delivery tray, and the amount of noises attributable to the impact. Further, in the case of this embodiment, the delivery tray controlling means does not require a driving force source dedicated to the unfolding of the delivery tray, and an operation dedicated to the unfolding of the delivery tray. In other words, the delivery tray can be automatically unfolded by utilizing the operations which are carried out by the apparatus main assembly to record an image, and the driving force source necessary for recording. 
         [0065]    Further, in the second embodiment, it is unnecessary to move the carriage  41  by an additional distance to allow the delivery tray to unfold itself. Therefore, it does not occur that the carriage  41  is adversely affected by the unfolding of the delivery tray; the unfolding of the delivery tray does not affect the torque for driving the carriage  41 , and the vibrations which occur at the end of the unfolding of the delivery tray do not adversely affect the carriage  41  during a recording operation. Further, it is unnecessary to increase in size the recording apparatus. Incidentally, the operation for moving the carriage  41  to the position indicated by the double-dot chain line in  FIG. 12  has to be carried out between when a recording start command is received and when the carriage  41  begins to be moved for recording. 
         [0066]    Incidentally, in the preceding embodiments, the recording apparatuses were ink jet recording apparatuses. However, the application of the present invention is not limited to ink jet recording apparatuses. That is, the present invention is also applicable to recording apparatuses of various types, for example, the laser beam type, thermal transfer type, thermal element type, wire-dot type, etc., just as effectively as it is to ink jet recording apparatuses. 
         [0067]    Each of the preceding embodiments of the present invention makes it possible to optimize the amount of the moment with which the delivery tray is provided when it is unfolded. Further, not only do they allow the delivery tray to unfold itself, but also, they reduce the speed at which the delivery tray unfolds, reducing thereby the impact which occurs at the end of the unfolding of the delivery tray. 
         [0068]    While the invention has been described with reference to the structures disclosed herein, it is not confined to the details set forth, and this application is intended to cover such modifications or changes as may come within the purposes of the improvements or the scope of the following claims. 
         [0069]    This application claims priority from Japanese Patent Application No. 226565/2006 filed Aug. 23, 2006, which is hereby incorporated by reference.