Patent Publication Number: US-6669188-B1

Title: Multi-positional, rotatable/large substrate backstop guide

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to handling of substrates and, in particular, to a multi-positional, rotatable/large substrate backstop guide for a tray that holds substrates of different widths and lengths for feeding within a printing machine. 
     2. Description of Related Art 
     In a typical printer/copier, one or more suitable trays for supporting stacks of substrates or sheets are provided with the sheets being fed, in seriatim, therefrom. These trays rely on guides prior to feeding to align the sheets and may include side and rear guides adapted to engage the side edge portion and rear edge portion of a sheet stack. Usually, a pair of sheet guides is provided for locating and retaining the sheets in predetermined feeding position normal to the direction of sheet feed. A sheet stop locates the sheets in the sheet feeding direction. 
     For example, a tray adapted to support a stack of sheets is shown in U.S. Pat. No. 4,607,834 issued Aug. 26, 1986 to Richard M. Dastin that is adjustable to accommodate stacks of sheet material of different widths and lengths. The rear registration and the side registration surfaces are moved in unison with one another so as to engage the rear and side edges of the stack of sheet material respectively. 
     In FIGS. 4 and 5 of U.S. Pat. No. 4,505,575 to Stephen A. J. Palumbo, issued Mar. 19, 1985 main and auxiliary paper trays are disclosed that include a movable sheet elevator or base onto which a stack-like supply of copy sheets may be placed for use by a copier or printer. A pair of movable sheet guides is provided for locating and retaining the copy sheets in a predetermined feeding position normal to the direction of sheet feed. A fixed stop member is located in the rear of each paper tray in order to locate the copy sheets in the sheet feeding direction. 
     A self-centering adjustable feed tray assembly is disclosed in U.S. Pat. No. 5,332,209 issued Jul. 26, 1994 that includes a pair of edge guides opposedly arranged about the centerline of the tray. Movement of one of the edge guides results in the corresponding movement of the other about the centerline. With the use of a clutch disc, either paper guide may be moved independently of the other effectively changing the centerline relative to the feed path of a transport. 
     Even though the above-mentioned adjustable substrate trays are useful, there is still a need for a tray that can supply edge support near the back edge of large sheet stacks, for example, 11″×17″ or larger in order to prevent the trail edge of large size substrates from rotating while the tray is being closed with too much force. Rotation of the substrates would cause their lead edges to be skewed, giving a higher probability of a substrate jam. The conventional edge guide does not extend back far enough to provide support in this area. Typically, this edge support function is attempted by using a fixed support which can only accommodate two paper sizes (11″×17″ and A3) or a sliding guide that is difficult to access. However, the rear guide cannot be made wider to support wider substrates such as 11″, A3, 12″ &amp; 12.6″ because of close proximity to another assembly within a copier/printer. A molded stop feature is not feasible because 12″ and 12.6″ wide substrates have a larger width/length ratio. 
     SUMMARY OF THE INVENTION 
     Accordingly, pursuant to the features of the present invention, an improved substrate feed tray is disclosed that answers the above-mentioned problems by providing a tall backstop guide that is attached to the bottom of the feed tray and which rotates about a vertical axis into three positions 45° apart, presenting a different surface to a stack of substrates in the tray in each of two positions and two different surfaces to a stack of substrates in a third of the three positions of the backstop guide. Each surface accommodates a different substrate size and thereby accommodates four different widths of substrates. The backstop guide includes a cam member that is positioned in close proximity to a back wall of the tray and is adapted to be flexed into the back wall of the tray when a load is applied to the backstop guide by the stack of substrates shifting inboard due to excessive tray closing force being applied to the tray by an operator. Thus, the excess force will be transmitted to the tray&#39;s back wall. Also, by rotating instead of sliding, the backstop guide of the present invention makes it easy to change positions with no binding, and is easy to access and manipulate by grasping the top of the guide. 
     These and other features and advantages of the invention are described in or apparent from the following detailed description of the exemplary embodiments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing and other features of the instant invention will be apparent and easily understood from a further reading of the specification, claims and by reference to the accompanying drawings in which like reference numerals refer to like elements and wherein: 
     FIG. 1 is a schematic plan view of a substrate tray employing the multi-positional, rotatable/large substrate backstop guide of the present invention therein; 
     FIG. 2 is an enlarged, partial schematic elevational view of the substrate tray of FIG. 1 with the multi-positional, rotatable/large substrate backstop guide of the present invention located therein and positioned in one of three positions; 
     FIG. 3 is an enlarged, partial schematic elevational view of the substrate tray of FIG. 1 showing the multi-positional, rotatable/large substrate backstop guide of the present invention positioned in a second of three positions; 
     FIG. 4 is a partial schematic plan view of the backstop guide of FIG. 1 showing a cam member that cushions the backstop guide in the event of movement against a back wall of the tray; and 
     FIG. 5 is a partial schematic plan view of the backstop guide shown in FIG.  1  and shows various detent positions for the backstop guide. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     While the present invention will be described in connection with a preferred embodiment thereof, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims. 
     For a general understanding of the features of the present invention, reference is made to the drawings. In the drawings, like reference numerals have been used throughout to identify identical elements. FIG. 1 schematically depicts a plan view illustrating a tray that supports substrates or sheets for feeding within a machine for further processing, such as, a copier/printer and incorporating the features of the present invention therein. It will become evident from the following discussion that the multi-positional, rotatable/large substrate backstop guide of the present invention may be employed in a wide variety of trays and machines and in not specifically limited in its application to the particular tray or machines specifically mentioned herein. 
     Referring now to FIG. 1, there is shown a plan view illustrating a substrate tray  10  that is adapted to be loaded with a stack of substrates and pushed in the direction of arrow  7  in order to position the substrates into a center registration machine for feeding the substrates out of the tray by conventional means (not shown) in the direction of arrow  8 . As shown, substrate tray  10  includes a back wall  12 , a front wall  14 , a side wall  11  and a registration wall  15 . A moveable base member  13  is positioned within the walls of the tray and is raised by an elevator (not shown) to predetermined positions so that the topmost substrate in a stack of substrates positioned thereon can be fed therefrom over registration wall  15 . Substrates are loaded into the tray by positioning them between adjustable rear (inboard) edge guide  16 , front (outboard) edge guide  17 , and trail edge guide  18 . In addition, as will be explained in detail hereinafter, and accordance with the present invention, a multi-positional, rotatable/large substrate guide  30  is shown positioning 11″×17″ substrates  20  for feeding in FIG.  1 . 
     A machine, such as a conventional copier or printer, with a center registration system, requires two movable edge guides that align and register the substrates at a preferred location on movable base member  13  of FIG.  1 . Thus, rear edge guide  16  has a generally planar surface, normal to base member  13 , adapted to contact one side edge of substrates  20 . Edge guide  16  is mounted slidably on base member  13  and moved in the direction of edge guide  17 . Similarly, edge guide  17  engages the other edge of substrates  20 . Edge guide  17  has a generally planar surface, normal to base member  13 , in engagement with the other side edge of substrates  20 . Edge guide  17  is also mounted slidably on base member  13  to move in the direction of edge guide  16 . The distance between edge guide  16  and edge guide  17  corresponds to the width of the substrates supported on base member  13 . Edge guide  16  and edge guide  17  move in unison with one another and are adapted to move either inwardly toward one another or outwardly away from one another depending upon the size of the substrates being supported on base member  13 . In addition to edge guides  16  and  17 , the substrates must be properly positioned lengthwise with respect to base member  13 . This is achieved by use of rear guide  18 . Rear guide  18  is mounted slidably on base member  13  to move in the direction of arrow  8 . In this way, the length of the area on base member  13  may be adjusted so as to correspond to the length of the substrates  20  supported thereon. Rear guide  18  has a generally planar surface, normal to base member  13  and to the planar surfaces of edge guides  16  and  17 , adapted to be in engagement with the rear edges of substrates  20 . In this way, substrates  20  are positioned lengthwise so as to be in a substrate feeding position. Conventionally, a suitable stepper motor and cam member can be employed to automatically position edge guides  16  and  17  and rear guide  18 , if desired. 
     In FIG. 2, and in accordance with the present invention, a multi-positional, rotatable/large substrate backstop guide  30  is positioned next to backstop or back wall  12  in order to prevent the trail edge of large size substrates from rotating while the tray is being closed by an operator in the direction of arrow  7  of FIG. 1 with too much force. Backstop guide  30  prevents rotation of the substrates that will likely cause a substrate jam within the machine, thereby necessitating unwanted machine operator intervention. Backstop guide  30  is attached to the bottom of tray  10  and rotates about a vertical axis into three positions 45° apart, presenting one of four surfaces  31 ,  32 ,  33 , or  34  to the substrates. Each surface accommodates a different substrate size. For example, surface  31  accommodates substrates that are 12.5″ and 12.6″ wide, surface  32  accommodates substrates 12″ wide, while surface  33  is used with A3 size substrates and surface  34  is used when substrates 11″ in width are required. 
     As shown in FIGS. 2 and 3, backstop guide  30  is rotatably adjustable about a vertical axis and is biased against rotation by a compression spring  50 . An advantage of backstop guide  30  is that it is easy to access and rotate into any one of three positions without binding occurring by grasping handle portion  60  of the backstop guide and turning it in a clockwise or counter-clockwise direction. A graphics label  80 , as shown in FIGS. 2 and 3, on tray  10 , as well as, graphics on the top of backstop guide  30  will instruct an operator where the backstop guide should be rotated to accommodate various substrate sizes (i.e., 11″, A3, 12″ and 12.6″). Backstop guide  30  is spaced a minimal distance from back wall  12  and includes a cam member  38  shown in FIGS. 4 and 5, that allows the backstop guide to rest against back wall  12  of tray  10  if an operator shoves the tray into a machine with enough force to shift substrates against the guide. Cam member  38  includes a curved portion  39  that facilitates contact with back wall  12  in any position backstop guide  30  is rotated, if substrate shifting occurs for any reason. When a load is applied to the backstop guide by a stack of substrates shifting inboard, any forces will be transmitted to the tray back wall  12 , thus registering the substrates and minimizing skewing of the substrate stack and preventing jams. In FIG. 4, backstop guide  30  is shown positioned to accept A3 and 11″×17″ substrates. A stop member  70 , shown in FIG. 1, prevents over rotating guide  30  in a clockwise direction and stop member  75 , shown in FIG. 4, prevents over rotating the guide in a counter clockwise direction. 
     An operator positions backstop guide  30  by grasping handle portion  60  and rotating the guide into any one of three detent positions that are molded into tray  10 . For example, in FIG. 5., detents  35 ,  36  and  37  are shown with the backstop guide  30  being positioned to accept 12.6″×18.5″ substrates. A Protruding member (not shown) extends from a bottom surface of backstop guide  30  and is adapted to fit into any one of the multiple detents in order to stabilize the guide in any one of predetermined positions. The detents are 45° apart. Backstop guide  30  is held in each detent position by conventional means, such as, a compression spring  50 . 
     It should now be understood that a simple, low cost substrate guide has been disclosed that is compact and accommodates various substrate widths. The substrate guide is attached to the bottom of a tray and rotates about a vertical axis into one of three positions 45° apart and thereby being able to present multiple registration surfaces to different substrate stacks placed into the tray. Each of two of the three positions accommodate different substrate sizes while the third position accommodates two different substrate sizes and a cam portion of the substrate guide is adapted to flex into contact with a back wall of the tray to prevent rotation or skewing of the substrate stack if the tray is pushed into a machine with too much force. 
     While the invention has been described in conjunction with the specific embodiments outlined above, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiments of the invention as set forth above are intended to be illustrative and not limiting. Various changes may be made without departing from the spirit and scope of the invention as defined herein.