Abstract:
A sheet collecting device for collecting sheets leaving the printing device, which includes a delivery rack for collecting sheets, a front edge stopper for collecting the front edge of a sheet in a first position of the sheet collecting device in which the sheet is deposited on the delivery rack, and wherein the sheet collecting device can be placed in a second position in which the sheets can be deposited on the delivery rack without the intervention of the front edge stopper.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a sheet collecting device for a printing device for collecting sheets leaving the printing device, which includes a delivery rack for collecting sheets, and a front edge stopper for collecting the front edge of a sheet in a first position of the sheet collecting device in which the sheet is deposited on the delivery rack. 
   Sheet collecting devices of this kind are frequently used in combination with a printer. They are generally heavy structures, inflexible and not well arranged for handling sheets of different sizes or qualities. In addition, these sheet collecting devices occupy considerable space in offices and this is particularly disadvantageous when not in use. 
   SUMMARY OF THE INVENTION 
   The object of the present invention is to obviate these and other disadvantages. To this end, according to the present invention, a sheet collecting device is provided which can be placed in a position in which the sheets can be deposited on the delivery rack without the intervention of the front edge stopper. As a result, both flat sheets and rolled-up prints can be collected with one collecting device. In another embodiment of the sheet collecting device according to the present invention, the front edge stopper is mounted at the front of the sheet collecting device and the delivery rack is mounted at the back, wherein when used in the first position the front of the sheet collecting device faces the printing device and when used in the second position the back of the sheet collecting device faces the printing device. Thus the rotation of the sheet collecting device through 180° enables the collecting device to be used for collecting rolls, for example, without any further conversion. 
   In another embodiment of the sheet collecting device according to the present invention, the sheet collecting device comprises a tubular frame with two substantially U-shaped tubes, a front tube and a back tube, both provided with wheels. This results in an easily movable and particularly light and hence cheap collecting device. 
   In another embodiment of the sheet collecting device according to the present invention, the front edge stopper comprises a slidable part, the distance of which from the top part can be adjusted. This makes the sheet collecting device particularly suitable for handling all formats of receiving sheets. 
   In still another embodiment of the sheet collecting device according to the present invention, a scale graduation is disposed on the non-slidable part of the front edge stopper. A scale graduation of this kind enables a reliable and accurate adjustment of the device so that practically any sheet format can be deposited without malfunction. 
   In yet another embodiment of the sheet collecting device according to the present invention, the front tube and back tube construction is collapsible. As a result, when the sheet collecting device is not in use it can be readily stored, thereby occupying very little space. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other advantages of the sheet collecting device according to the present invention will be described in detail hereinafter and explained with reference to the following Figures, wherein: 
       FIG. 1  is a 3D illustration of the sheet collecting device according to the present invention; 
       FIG. 2  is a diagram showing the sheet collecting device according to the present invention in the delivery position; 
       FIG. 3  is a diagram showing the sheet collecting device according to the present invention in the collecting position; 
       FIGS. 4 to 8  show the operation of the sheet collecting device according to the present invention in the delivery position; 
       FIGS. 9 to 11  show the operation of the sheet collecting device according to the present invention in the collecting position; 
       FIGS. 12 and 13  are a detail of the sheet collecting device according to the present invention, and 
       FIG. 14  is a detail of the front edge stopper in the sheet collecting device. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  is a 3D illustration of the sheet collecting device  10  according to the present invention. The frame consists of two U-shaped tubes  13 ,  15  of about 20 mm cross-section. The front tube  13  and the rear tube  15  are interconnected by means of a hinge  18 . The hinge is constructed in the form of a bolt which so connects the two tubes that they can still pivot around said bolt. Struts  25  provide a rigid structure. At the ends of the tubes  13 ,  15  castors  21  are provided by means of which the sheet collecting device can easily be moved or turned. 
   A hinge rod  19  forming part of the delivery rack  11  is disposed on the front tube  13  and preferably as a part of the hinge  18 . A rack  20  is fixed on the hinge rod  19 . This rack serves to collect printed sheets originating from a printer or copier. The delivery rack  11  is adjustable at an angle around the hinge rod  19 . Two angle adjusters  17  are mounted on the back tube  15  for the angle adjustment (see  FIGS. 12 and 13 ). Adjustment rod  22  can be moved up or down with this, so that the angle of the rack  20  to the horizon can be adjusted. In an extreme position of the angle adjuster  17  the rack  20  hangs vertically down. A front edge stopper  12  is mounted at the top part  16  of the front tube  13 . This front edge stopper  12  consists of a non-slidable part  24  consisting of two rods fixed on the top part  16  ( FIG. 14 ). The front edge stopper  12  also has a slidable part  23  by means of which a tray  52  can be moved along the rods of the non-slidable part  24 . The tray  52  is provided with a vertical and horizontal toothed strip  50 ,  51  to ensure that sheets brought into the tray do not curl up and vanish from the tray  52 . The front edge of a sheet of paper is thus retained by the teeth. A scale graduation is mounted on the non-slidable part and indicates the position of the slidable part  23 . 
     FIG. 2  is a diagram showing a printer  30  with an outlet opening  31 . The sheet collecting device is in the delivery position (first position) against the printer. The numbering of the parts of the sheet collecting device is identical to the numbering used in  FIG. 1 . 
     FIG. 3  is again a diagram showing the printer  30  with the outlet opening  31 . The sheet collecting device has now been placed in the second position (collecting position) against the printer. By means of the castors  21  the sheet collecting device can be turned through 180° in order to move the sheet collecting device from the delivery position to the collecting position. 
     FIGS. 4 to 8  show the operation of the sheet collecting device in the delivery position. In  FIG. 4 , a copy sheet  40  leaves the printer  30  via the outlet opening. In  FIG. 5  said sheet  40  reaches the slidable part  23  of the front edge stopper and is prevented by a toothed strip ( 50 ,  51  in  FIG. 14 ) from any further passage or pushing into the front edge stopper. The sheet  40  then forms a slack over the top part  16  of the front tube  13  ( FIGS. 6 and 7 ) and when the sheet is cut off it is delivered on to the rack  20  of the delivery rack  11 . A large quantity of long sheets can be delivered in this way. To guide the sheet in the front edge stopper guide strips  53  ( FIG. 14 ) of plastic can be used. If the sheets are somewhat smaller, so that they still fit on the rack  20 , rear edge stoppers  56  can be used. 
   There is an optimum height setting of the front edge stopper  12  for each print length. This is overall such that considered from the top  14  of the front tube  13  approximately half the length of the sheet hangs down on both sides. The sheet must also have sufficient slack to be reliably deposited. A scale graduation is provided for this purpose on the non-displaceable part  23  of the front edge stopper and standard print formats are shown thereon. 
   The angle of the rack is also so adjusted that the sheets roll sufficiently over the rack but without sliding therefrom and dropping on the floor. A correctly adjusted angle also prevents curled sheets from rolling back over the rack after being cut off. The optimum position can be adjusted by reference to material data of the sheet (such as gram weight of the paper, coating, weather conditions and so on) and the adjustment mechanism ( FIGS. 12 and 13 ). For this purpose the angle adjuster  17  is provided with specially made holes that can rest on a receiver  42 . The sheets may be wet as a result of the considerable quantity of ink deposited thereon or due to high relative humidity of the air. Such sheets do not roll easily over the rack and tend to crease. For such sheets the rack must be in the lowest position. The rack can be placed in a vertical position. 
   Some sheets cannot be collected in the delivery position of the sheet collecting device, for example, very short sheets or sheets of thick material or material which curls very considerably. For these applications the sheet collecting device is turned through 180° and placed against the printer in the second position (collecting position). 
     FIGS. 9 to 11  show the operation of the sheet collecting device in the collecting position. The sheet  40  now falls directly on to the rack  20  of the delivery rack  11 . Here again the angle of the rack can be set to the optimal value for the material. The sheet collecting device is provided with four castors each having a braking mechanism and can thus be fixed in the correct position behind the printer. For this purpose the printer can be provided with the correct stops so that the position will always be the same. After, for example, 100 sheets have been deposited on the sheet collecting device, the rack can also be moved to a different position where the sheets can be processed further. The collecting width of the sheet collecting device is suitable for AO formats but the depth of the sheet collecting device is such that it can be pushed through current doorways. The strut  25  for this purpose is not wider than 75 cm. 
   The tubular frame of the sheet collecting device is also so made that the sheet collecting device can be collapsed and thus compactly stored. Thus the installation of the device requires no more than unfolding of the frame. 
   The present invention is not restricted to the embodiment described hereinabove and the skilled man will be able to devise many other embodiments all of which will however fall within the scope of the following claims.