Abstract:
Certain designs of paper feeding devices used in copiers and printers require that an edge of a stack of sheets be in close contact with a slanted surface. An apparatus engages an opposite edge of the stack to urge the stack against the slanted surface, so that the stack assumes a parallelogram shape. The apparatus includes a plate which is movable from a vertical, upright position to a slanted position. Means are provided to cause the plate to move to the slanted position in response to the closing of a paper tray of a printer or copier.

Description:
FIELD OF THE INVENTION 
     The present invention relates to office equipment such as printers and copiers, and in particular relates to an apparatus for holding a stack of sheets, as would be used in a paper supply for such equipment. 
     BACKGROUND OF THE INVENTION AND DESCRIPTION OF THE PRIOR ART 
     U.S. Pat. No. 5,377,969 describes a feeding apparatus for drawing sheets from a stack of paper, as would be used in a printer or copier. A stack of sheets is held so that one side of the stack abuts a slanted surface, so that, viewed elevationally, the stack assumes a generally parallelogram shape. The slanted surface is exploited by rollers which engage the top sheet of the stack, to ensure that exactly one sheet is drawn at a time when the printer or copier is in use. 
     The present invention relates to a device for holding a stack of sheets in a parallelogram shape. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the present invention, there is provided an apparatus useful in retaining a stack of sheets, comprising a plate for engaging an edge of the stack of sheets, and a mechanism for selectably positioning the plate in an upright position and a slanted position. 
     According to another aspect of the present invention there is provided a printing apparatus, comprising a paper tray for retaining a stack of sheets, a plate for engaging an edge of the stack of sheets and a mechanism for selectably positioning the plate in an upright position and a slanted position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevational sectional view of a paper supply drawer, as used in a copier or printer, using the present invention. 
     FIG. 2 is a perspective view of a portion of the exterior of a printer, showing an embodiment of the present invention. 
     FIG. 3 is a perspective view of one embodiment of the present invention. 
     FIG. 4 is a perspective view of another embodiment of the present invention. 
     FIG. 5 is a perspective view of another embodiment of the present invention. 
     FIG. 6 is a perspective view showing an additional aspect of the present invention. 
     FIG. 7 is a simplified elevational view of a xerographic printer including the present invention. 
    
    
     In the above Figures, like numerals indicate functionally equivalent elements in various embodiments. 
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 is a sectional elevational view of a paper supply drawer, or tray, as would be found, for instance, in a printer, copier, or other office equipment, showing some essential features of the present invention. With most relevance to the present invention, the drawer  100  defines a slanted surface  102 , which is a generally flat surface disposed approximately 30 to 60 degrees from the vertical. As described above in the &#39;969 patent, a certain type of paper feeding apparatus exploits such a slanted surface, and it is desirable that a paper stack, such as indicated in FIG. 1 as S, be disposed with one of its edges abutting such a slanted surface. 
     According to the illustrated embodiment, one edge of a paper stack S is caused to abut slanted surface  102  by the presence and action of a plate  10  in contact with an opposite side of the stack. When a stack S is initially placed in the drawer, with the typical vertical sides (such as when removed from a package), one side of the stack is in general contact with plate  10 , which is in a substantially vertical “upright position” as shown. After the stack S is loaded, the plate  10  is moved to a substantially slanted position as shown in phantom and indicated as  10 ′. When plate  10 ′ is in the second position, the opposite side of stack S is pushed against slanted surface  102 , and the stack S generally assumes a parallelogram shape, as shown. 
     Also shown in FIG. 1 is a lever  12 , which interacts with plate  10 , and is shown in a position which is consistent with plate  10  being in its upright position. Shown in phantom and indicated as  12 ′ is the lever in a position consistent with plate  10 ′ being in its second position. The various possible mechanical means by which lever  12  interacts with plate  10  will be discussed below. 
     FIG. 2 is a perspective view of a portion of some office equipment, such as a printer or copier, in which a paper supply drawer or tray such as  100  is used. As is familiar, such a drawer  100  can be slid in and out from the body of the machine so that paper can be re-supplied to the machine. According to this embodiment of the invention, lever  12  is shaped and located so that, when drawer  100  is pushed back into the machine, such as after loading a stack of paper therein, lever  12  contacts a “contact surface” of the machine and is thus pushed downward as the drawer  100  is closed. As the lever  12  is pushed down, through a mechanism of a type which will be described in detail below, plate  10  is caused to move from its upright position to its slanted position, as described above. In turn, a stack of paper placed in the drawer  100  assumes the desired parallelogram shape and is pressed against the slanted surface  102 . In brief, pushing the drawer  100  in causes the stack S to assume the parallelogram shape. According to this aspect of the invention, the contact surface of a machine for this purpose can be an outer surface of the machine, as shown in FIG. 2, or can be on a member internal to the machine. Alternately, lever  12  can be in effect attached to a member within the body of the machine. 
     In order to provide the desired interaction between lever  12  and plate  10 , any number of types of mechanisms can be used. Below, certain mechanisms will be basically described, but it will be apparent that many variations can be made to the described mechanisms within the spirit and language of the claims. 
     FIG. 3 is a perspective view of one embodiment of the present invention. In this embodiment, plate  10  is movable between and upright position and a slanted position, as shown. Plate  10  assumes its slanted position when lever  12 , which is pivotably mounted relative to a main portion  16  of a mechanism which supports plate  10  in a particular position, is in a down position (as opposed to the up position, such as shown in FIG.  2 ). The mechanism includes at least one camming surface, such as  18 , which in effect transfers the motion of the downward positioning of lever  12  to move the plate  10  to its slanted position. When the lever  12  is pulled up again, the plate  10  returns to an upright position, either through the action of another camming surface, or of springs associated with the mechanism (not shown). 
     FIG. 4 is a perspective view of an alternate embodiment of the present invention. In this case, the plate  10  is once again caused to change position by the action of a lever  12 , but the lever  12  slides relative to the basic mechanism instead of pivoting. The member forming lever  12  slides along a bar  20  while a surface thereof engages a camming surface  22  associated with plate  10 . In this particular embodiment, when lever  12  is slid to the right in the Figure, the plate  10  is moved to its slanted position; when the lever  12  is slid to the left, plate  10  returns to an upright position, aided by spring  24 . Although a very simple mechanism is illustrated, many practical variations on the design can be contemplated to allow the sliding action of lever  12  and resulting positioning of plate  10 . 
     In the FIG. 4 embodiment, the lever  12  can be attached to or otherwise contact other surfaces (not shown) of the rest of a machine, to achieve the principle of “automatic” positioning of plate  10  to its slanted position when a paper tray or drawer is closed. The lever  12  can contact the outside of a machine, as largely shown in FIG. 2 above, or contact or be attached to a member within the body of the machine. In the FIG. 4 view, if the drawer and the attached mechanism including lever  12  is pushed to the left, the lever  12  will contact a surface of the machine, be pushed to the right, and therefore place plate  10  in its slanted position. 
     FIG. 5 is a perspective view of another possible embodiment of the present invention. Here, the plate  10  is more or less directly moved, such as by a user&#39;s hand, into a slanted position as needed, and a lever  12 , pivotably mounted on a surface (such as a main portion  16  as shown, or even a bottom surface of a paper tray or drawer), functions mainly as a “stop” to hold plate  10  in its slanted position. In this case, the “mechanism” for positioning plate  10  basically comprises the hinge on which plate  10  is mounted. 
     As is well known in the art of office equipment, a paper tray or drawer is typically provided with adjustable parts so that the tray can accommodate paper stock of various sizes. Returning to FIG. 1 above, it is desirable that the position of plate  10  in terms of distance to slanted surface  102  be adjustable so that a stack S of a range of sizes can be placed properly in the tray. To this end, there is provided means for adjusting the position of plate  10 , and such means can include a track  14 , which can be defined by a set of teeth or other structure in the body of tray  100 . The plate  10  and its associated mechanism moves along track  14  as needed to conform to a stack S of a given size. 
     FIG. 6 is a perspective view of another aspect of the present invention, what can generally be called a slidable mount for adjusting a position of the plate  10 , particularly relative to slanted surface  102  such as shown in FIG. 1. A catch  30 , which can be of any design, engages the teeth of track  14  to retain the plate  10  in a selected position relative to slanted surface  102 . Any basic design of such a slidable mount, generally familiar in the art, can be provided, with or without the illustrated teeth in track  14 . Another aspect of the invention is disposing the catch  30  or equivalent element underneath lever  12  when lever  12  is in a position consistent with plate  10  being in a slanted second position. The position of lever  12  thus makes catch  30  largely inaccessible, so that the position of plate  10  cannot be changed when the plate is in its slanted position. 
     Although the illustrations show plate  10  as a substantially solid plate with a flat surface, it will be appreciated that the plate  10  can be of any practical configuration, such as including openings, fingers, ridges, etc. as required to enhance performance. 
     FIG. 7 is a simplified elevational view of an office machine, in this case a xerographic or electrostatographic printer  200  (which may also function as part of a copier or facsimile machine) embodying the present invention. Sheets from a tray  100  are stacked in a parallelogram-shaped stack S by the action of plate  10 . Sheets are individually drawn by feed head  202  from stack S in a manner such as shown in the &#39;969 patent, and sent through paper path  204 . Each sheet receives marking material forming an image from charge receptor  206 , and the marking material is fused in fuser  208  and deposited in tray  210  or other finishing device.