Document feeder for printing equipment

Abstract: The document feeder for printing equipment as designated here, is designed to draw certain types of document, one by one, from a pile or stock of these to a device which prints certain characters or devices. The pile of documents is cons­ tantly pushed towards a set of tractor wheels (10, 11) by the action of a continuous pressure device (7), while the document is passed along the corresponding guide (1) in the direction of the exit (13) between a set of selector wheels (14, 15, 15′, 15″) equipped with thoroidal rubber bands (16, 17). These are arranged in such a way that the roller (14) on one side of the guide turns in forward direction, while on the other side of the guide (1) another roller (15) with subsidiary rollers (15′, 15″) connected to it turns in the opposite direction, tend­ ing to pull the documents back, thus preventing any documents in contact with it from moving forward. Finally, documents are moved towards the end (13) of the guide (1) by a last wheel set (18) close to the exit point.

Description: PURPOSE OF THE INVENTION This invention, as the title of this description states, is a document feeder for printing equipment, whose purpose is to draw single documents from a pile and deliver them to an auxiliary apparatus associated with a printer, where characters or devices will be printed on them. BACKGROUND Besides the various types of printing equipment for the treatment of different kinds of documents, there is a type used in banks and allied institutions which handles a very specific sort of document, such as the cheque, printing a series of characters, codes or devices on them for identification by the bank. To have these characters or codes printed on them, such documents will normally be passed through a printing machine, which will have attached to it a feeder device to deliver the documents singly from a storage zone to the printer. There are a number of such feeders in existence, provided with a guide along which the document is drawn by a set of tractor rollers. The documents are piled on a kind of tray in such a way that the pile rests on a set of wheels or rollers which supply the initial traction necessary to draw out the bottom document and pass it along to another set of selector rollers. These are arranged in such a way as to permit the passage of one document only, the document then being pushed by a last roller into the printing machine itself. It goes without saying that the tractor and selector rollers will be duly arranged and synchronised so that each starts to move at the right moment, and can be stopped when required. This is achieved by means of drive and/or gearing systems powered by a motor. In any case this type of device has a number of drawbacks: for example, the tray or plate bearing the pile of documents for processing is pushed towards the tractor wheels by a spring or similar element, which means that when the pile is high, the pressure exerted on the documents is great; however as the pile diminishes, the pressure decreases, and therefore the documents are not pressed against the tractor wheels with constant force. Such feeders moreover lack any means of adapting to documents of different lengths. Another disadvantage of these feeders is that the selector mechanism permitting the passage of only one document at a time consists at best of a simple pair of rollers set tangentially. This means that selection occurs along a single line, that is at the tangent of the two rollers, and is much less efficient than a broad surface, as is the case with the invention described here. European Patent No. EP-A-0 003 372 is known, which relates to a mechanism for documents separation, which obliges the documents to pass along the circumference of a wheel, the documents being folded over themselves, and being obliged to follow the wheel circumference effecting a rotation over the start direction. DESCRIPTION OF THE INVENTION The document feeder proposed here is designed to provide a totally satisfactory solution to these problems. To this end, its operation and function offer a maximum of simplicity and efficiency. More specifically, one of the innovative features of this feeder is that the inclined tray on which the documents rest awaiting access to the guide has an end-piece which can slide in or out to accomodate documents of any length. Furthermore, the document-bearing tray contains a groove through which a pushing element passes and acts on the pile of documents by force of gravity alone, thus ensuring a constant pressure irrespective of the height of the pile. Another feature of the invention is that one of the two tractor wheels or rollers against which the pile rests has protrusions on its circumference which jog the pile, causing it to vibrate and hence serving to separate papers which may have become adhered to one another as is frequently the case with new documents, thus facilitating the subsequent selection. A further improvement incorporated in the proposed feeder lies in the selector mechanism. This comprises a roller encircled by three toric rubber bands, in opposition to which and at alternating heights are two toric bands mounted over two rollers so as to present an elongated surface facing the three-banded roller. No two documents may pass at once since the single roller revolves in the opposite direction from the double opposing roller; the single roller, which draws the document forward, exerts more force than the other two, which tend to pull the document backwards, so that the document in contact with the three-banded roller is drawn towards the output end, while any document or documents in contact with the opposing bands are drawn back. Hence, only one document at a time can possibly pass along to the output end, where it is expelled by a final tractor wheel. Finally, the feeder is provided with a photo-detector to detect documents once they are selected and relay the appropriate run or stop commands to the wheels; the wheels are governed by a clutch mechanism which, when engaged, turns all the wheels or rollers except the final tractor wheel, so that a document is drawn out and selected; when the clutch is disengaged, the initial tractor and the selector rollers stop, and, as the drive motor continues to run, the final tractor turns alone, pushing the document on through the exit. DESCRIPTION OF THE DRAWINGS In order to provide a fuller description and contribute to the complete understanding of the characteristics of this invention, the written explanation is accompanied by a set of drawings which, while purely illustrative and not fully comprehensive, show the following details: Figure 1: Side-view of the feeder showing the inclined tray on which the documents are stored before being drawn through, with the sliding end-piece for adjustment to any length of document. Figure 2: Angled view of part of the mechanisms making up the feeder, seen from the angle indicated X in Figure 1. Figure 3: View of another part of the mechanisms, seen from the opposite side to Figure 2, that is from the angle indicated Y in Figure 1. Figure 4: Plane view of the rollers with their toric bands which comprise the selector mechanism. Figure 5: Detailed view of the element attached to the storage tray which exerts constant, uniform pressure on the pile of documents. Figure 6: The same element as in Figure 5 seen from a different angle. Figure 7: Shows the arrangement of wheels linked together by a toothed belt and constituting the transmission to the tractor and selector wheels. RECOMMENDED STRUCTURE OF THE INVENTION Referring to the above drawings particularly Figures 1 & 2, it can be seen how the proposed feeder is structured around the guide 1 along which the documents are passed, preceded by an inclined tray 2 on which documents are piled for selection. Tray 2 is equipped with an end-piece 3 which can be slid away from or towards tray 2, thus adjusting to the required length of document. Tray 2, on which the documents are piled, has a groove 4 which admits the wheels 5 mounted on rollers 6 which form part of the pressure element 7 shown in Figures 5 and 6 The purpose of this element is to press the pile of documents with constant and uniform force against the tractor wheels which will be described in due course. This pushing device is formed by two parallel plates 7 between which are mounted two rollers 6. At the centre of each roller 6 is one of the wheels 5 which pass through the groove 4 on the tray 2 in such a way that the end plate 8 presses down on the last document in the pile. Obviously the pressure element may take some other form, the key point being that it exerts pressure solely by the force of gravity and not by means of springs or similar devices as is the case in traditional feeders, where the force exerted diminishes as the pile of documents shrinks. Thus for example, an alternative structure for pressure element 7 might be an arm traversing groove 4 with a forked end bearing a roller which presses down on the documents. This or any other structure will suffice as long as it exerts downward pressure by virtue of its own weight. The documents will therefore be piled on tray 2 edge-on to groove 4, in the correct position for entry in the guide 1 through the entrance 9. The pile of documents rests on a pair of tractor wheels 10 & 11 placed before the entrance 9 to the guide 1. Wheel or roller 10 has protuberances 12 on its periphery which, as the wheel turns, jog the pile of documents and thus separate any which may be stuck together, facilitating the subsequent selection of the document. As the documents are moved through the entrance 9 to the guide 1, two or more may easily pass through at a time, and it is therefore essential to ensure that only one at a time issues from the output end 13. The selection of one single document is achieved by means of a set of selector rollers. These comprise one roller 14 on one side of the guide 1 and three rollers 15, 15' & 15'' arranged on the other side. Roller 14 is provided with three toroidal rubber bands 16, as shown in Figure 4, while two toroidal bands 17 run between rollers 15 & 15'' while also running over intermediate roller 15'. Thus, when the documents bass through the entrance 9 into the guide 1, they will attempt to pass between roller 14 on the one side and rollers 15, 15' & 15'' on the other. Roller 14 revolves in a forward direction, that is, it tends to push the document towards the output end 13, while rollers 15, 15' & 15'' revolve in the opposite direction, in other words they tend to push the documents back towards the entrance 9. Later on we shall describe in detail how the selection works, that is to say how the set of rollers described ensures that no more than one document may pass through at a time. Following the selector rollers is a final tractor wheel 18 which draws the selected document towards the output end 13. Level with wheel 18 is a photo-detector 19, which detects the passage of each document and relays the appropriate commands for the initiation of a new cycle. All the rollers and wheels described so far are driven by a transmission system powered by a motor 20. This turns a pinion 21 mounted on its output shaft, and also a coaxial pulley wheel 22. This wheel is linked by a belt 23 to a second pulley wheel 24, at the other end of whose shaft is a pinion 25 which engages another pinion 26. On the shaft of pinion 26 is mounted the output tractor wheel 18. For its part, pinion 21 is linked by a toothed belt 27 to a crown wheel 28, whose shaft is equipped with a clutch. The clutch governs a pinion 29 which engages with a cog wheel 30, and it is this wheel, through the transmission system depicted in Figure 7, which powers the initial tractor wheels 10 & 11 and the selector rollers 14 and 15-15'-15''. Thus, on the same shaft as cog wheel 30 is wheel 31, which is linked by means of a toothed belt 32 with wheels 33, 34, 35, 36 & 37 by way of tensor rollers 38 & 39. Wheel 33 shares its shaft with initial tractor roller 10, and wheel 34 shares its with wheel 11. Roller 14 is moved by coaxial wheel 36, while rollers 15, 15' & 15'' are turned by wheel 35, which is coaxial with roller 15. When the motor starts, then, the transmission system turns output tractor wheel 18. Once a document has been selected, it is drawn by wheel 18 towards the output end 13, at which point it passes the photo-detector 19 and this signals the clutch to disengage. Up to this moment the clutch has been engaged and has hence been turning all the tractor and selector wheels and rollers in such a way that roller 14 draws the document in a forward direction while rollers 15-15'-15'' tend to push documents back. As roller 14 exerts the greater traction, the document in contact with it will be drawn forward, while any documents in contact with rollers 15-15'-15'' will be pulled back. Thus the selection is achieved, in other words a single document is passed through, since the greater traction exerted by roller 14 ensures that the one remaining document is not pulled backwards by rollers 15-15'-15''. Clearly by regulating the distance between the shafts of rollers 14 and 15 it will be possible to achieve optimum separation for different thicknesses of document.

Claims: Document feeder for printing equipment comprising, a guide (1) along which documents pass singly towards another apparatus which will print characters or devices on them, a storage tray (2) for documents inclined in such a way that the documents rest at all times on an initial set of tractor wheels (10,11) which move them towards the guide (1), a second set of wheels or rollers (14,15,15',15'') forming the selector mechanism, a motor which, through a transmission comprising belts and pulleys and/or pinions and chains, causes the drive and tractor elements to turn, a photo detector (19) level with a final tractor wheel (18), characterized in that, the inclined plate of the storage tray (2), on which the documents rest, is provided with a movable end piece (3) which may be slid in or away so as to provide a stable support for documents of any length, the base of said storage tray (2) has a groove (4) which acts as a guide for the movement of a device (7) which presses down the pile of documents constantly and uniformly, its force deriving exclusively from its own weight, one of the initial tractor wheels (10) has protuberances (12) on its circumference so that, when the wheel turns, it jogs the pile of documents causing them to vibrate and thus separating any papers which may be stuck together, said second set of wheels or rollers (14,15,15',15'') comprises one single roller (14) with three circumferential grooves, in each of which is set a toroidal rubber band (16), and, on the opposite side of the guide (1), a second roller (15) associated with two small rollers (15',15''), all three rollers being encircled by two toroidal bands (17) which thus form an elongated surface along the line of passage of the documents, said second set of rollers (14,15,15',15'') being disposed in such a way that the single roller (14) on one side of the guide (1) revolves in a forward direction while the other rollers (15,15',15''), on the opposite side of the guide, (1) revolve in the opposite direction, so that any documents in contact with the toroidal bands (17) forming the elongated surface tend to be pushed backwards until only one document remains between the rollers on the opposite side of the guide (1) and the single roller (14), said single roller (14) exerting a greater traction than the opposite set, and said single document is drawn forward and then passed to said final tractor wheel (18) which pushes it through the output end (13). Document feeder for printing equipment as specified in claim 1, characterized in that the assembly exerting pressure (7) on the pile of documents is ideally composed of a pair of rollers (6) mounted between two parallel plates, each of these rollers having a concentric wheel (5) of considerably larger diameter at its mid-point; these wheels fit into a groove (4) in the inclined plate against which the documents rest, while downward pressure is exerted on the pile of documents by another plate (8) fitted across the parallel plates bearing the rollers. Document feeder for printing equipment as specified in the foregoing claims, characterized in that the transmission mechanism includes a number of pulleys, wheels and belts linked to a clutch by means of which all the tractor wheels, including the selector rollers and excepting the final output tractor wheel (18), may be actuated at once. The final wheel may be activated together with the other wheels and rollers on engagement of the clutch, or it may turn independently.

Inventors: BLANCO MARTIN EMILIO, BLANCO MARTIN, EMILIO
Applicants: AMPER SA, AMPER S.A.
Application year: 1988
Main classification: B65H3
IPC codes: B65H3, B65H1