Document handler

Abstract: A document sheet feeding apparatus 24 for delivering successive documents to an imaging station of a copier 10. The document input apparatus 24 includes a document input tray 21 for receiving documents to be copied, a cover 44 arranged to be guided between a first position, in which the tray 21 is uncovered, allowing documents to be loaded therein, and a second position in which the cover 44 covers the tray 21. Drive means is provided for automatically driving the cover 44 from the first position to the second position, and control means 100 for controlling the drive means whereby the cover 44 is automatically driven into the second position prior to a document feeding operation from the tray 21.

Description: The present invention relates generally to a document handler and more particularly, but not exclusively, to a document sheet feeding apparatus for delivering successive documents to an imaging station of a copier. The noise associated with document handlers, particularly recirculating document handlers (RDHs), has been found to be a source of customer dissatisfaction. Noise is associated in particular with airflow, the document sheet acquisition "slap", and sheet impact noise while the sheets are in transport. Historically, the method of reducing the emitted document handler noise has been to add sound deadening material to the inside of the document handler and/or provide a manually operable cover over the otherwise open document tray of the RDH, as in the Xerox Corporation "5047" RDH, and some Eastman Kodak RDHs. Sound deadening reduces some noise, but the remainder of the noise is emitted from the open document loading area, that is, the document input station (tray area) of the RDH. Manual covers are disadvantageous in that they must be manually opened and closed each time a print job document is loaded into or removed from the RDH, and otherwise interfere with document loading and unloading. Semi-automatic platen covers are known, for different functions in some types of document handlers, as in 4,721,981, and art cited therein in Cols. 3 and 4, etc. In a typical document handler of the type often used with image input terminals, such as those used for providing electronic digital images (e.g., raster input scanners), or, more commonly, those used with light-lens optical imaging systems, documents are sequentially transported from a document input station to an imaging station. In the case of light-lens copiers, this is repeated many times in many recirculations of document sets in an RDH to provide precollated output from the light-lens copier. Some examples of such RDHs are disclosed in Xerox Corporation U.S. 5,026,044; 5,062,602; 4,831,419; 4,428,667; 4,469,319; 4,621,801; etc. As noted, in an attempt to reduce the noise emitted from the document input station, a manual cover has been provided in the Xerox Corporation "5047" copier's document handler. This manual cover can be pulled manually over the top of a document input tray at the document input station. An operator first loads the documents into the document input tray, pulls the cover over the tray and then operates the RDH. After the RDH operation has been completed the cover must be manually pushed back to uncover the tray and allow the unloading of the documents therein. Operators, however, often fail to make use of this cover either because they forget or are so rushed that they perceive its use as a delay, and thus leave it open. Customers thus still complain about the noise coming from the machine during its operation. One object of the present invention is to provide a document input apparatus having means whereby the cover movement is controllable automatically to ensure that the area above the document input tray is covered during the feeding operations when documents are being fed out of and back into the tray. Accordingly, the present invention provides a document input apparatus including a document input tray for receiving documents to be copied, a cover arranged to be guided between a first position, in which the tray is uncovered allowing documents to be loaded therein, and a second position in which the cover covers the tray, characterised by drive means for driving the cover from the first position to the second position, and control means for controlling the drive means whereby the cover is automatically driven into the second position prior to a document feeding operation from the tray. In a preferred embodiment the drive means is adapted to drive the cover back and forth between the first and second positions. Conveniently, the back and forth movement is executed in a horizontal plane. In a preferred embodiment a reversible drive means is provided for reciprocating the cover between its first and second positions, the cover reaching each of its first and second positions when a respective side edge of the cover abuts against a respective datum surface. Conveniently, the reversible drive means comprises a bidirectional motor, the motor being adapted to stall when a predetermined overload is encountered. By utilising a stallable drive means in this manner the need for sensors to sense the cover's position is obviated. In one embodiment there is provided switch means operable by an operator for signalling to the control means that a document feeding operation is to be initiated. In a preferred embodiment timing means, associated with the control means, is also provided. The timing means energises the drive means for a predetermined period prior to the start of the actual document feeding from the tray, the period being sufficient to ensure that the cover moves from its first position to its second position. The timing means also energises the drive means for a second predetermined period after the document feeding operation has been completed, the second period being sufficient to ensure that the cover moves from its second position to its first position. Conveniently the first period equals the second period. In an embodiment the drive means includes a belt and pulley arrangement coupled to a roller, the roller engaging the undersurface of the cover to drive the cover back and forth between the first and second positions. A shaft associated with the roller carries a paddle for engaging a projection, carried on the undersurface of the cover, when the cover has reached its second position, the paddle and said projection cooperating to prevent further rotation of the roller after the cover has reached its second position. The paddle on the shaft may also engage a further projection or lip on the undersurface or edge of the cover when the cover has returned to its first position, the paddle and said further projection or lip cooperating to prevent further rotation of the roller after the cover has returned to its first position. Guide means is provided for guiding the cover between its first and second positions. In one embodiment the guide means comprises an elongate guide rail extending parallel and adjacent to one side edge only of the cover. The cover is provided with two pairs of rollers, the rollers of each pair being spaced apart to be in sliding engagement with opposing surfaces of the the guide rail. It is well known and commonplace to program and execute printing, document, and/or paper handling control functions and logic with software instructions for conventional or general purpose microprocessors. This is taught by various prior patents and commercial products. Such programing or software may of course vary depending on the particular functions, software type, and microprocessor or other computer system utilized, but will be available to, or readily programmable without undue experimentation from, functional descriptions, such as those provided herein, or prior knowledge of functions which are conventional, together with general knowledge in the software and computer arts. That can include object oriented software development environments, such as C+ +. Alternatively, electronic control systems or methods may be implemented partially or fully in hardware, using standard logic circuits or a single chip using VLSI designs. In the description herein the term "document" or "sheet" refers to a usually flimsy physical sheet of paper, plastic, or other suitable physical substrate for images, whether precut or initially web fed. A job is normally a set of related sheets, usually a collated copy set copied from a set of original document sheets or electronic document page images, from a particular user, or otherwise related. As to specific hardware components of the subject apparatus, or alternatives therefor, it will be appreciated that, as is normally the case, some such specific hardware components are known per se in other apparatus or applications which may be additionally or alternatively used herein, including those from art cited herein. The invention will be described further by way of example, with reference to the accompanying drawings, substantially to scale, in which: Fig. 1 is a schematic side view of a copier having a recirculating document handler (RDH) with an automatic cover system in accordance with an embodiment of the invention; Fig. 2 is an enlarged view of the document handler and cover of Fig. 1, per se; Fig. 3 is an enlarged perspective view in more detail of the cover for the RDH of Figs. 1 and 2 and an exemplary guide and drive mechanism therefor; Figs. 4A and 4B are more detailed illustrations of the cover drive mechanism of Fig. 3, in two different perspective views; Fig. 5 is a side view of the drive mechanism and the cover in its open position of the embodiment of Figs. 1-4; Fig. 6 is a plan or bottom view of the cover and drive mechanism of Fig. 5, showing the cover in its closed position; Fig. 7 is a perspective view of the cover per se of Fig. 3; Fig. 8 is a section taken along the line A-A in Fig. 7; and Fig. 9 is a partial exploded view of the recirculating document handler and cover of Figs. 1-8. Fig. 1 shows a copier 10 with a document handling system 20 having a recirculatory input stacking tray 21, and also a side entrance shelf 22 for a semiautomatic document system into which documents may be individually inserted. The recirculating document handler 24 (RDH) of the document handling system 20 provides for automatically transporting individual registered and spaced document sheets onto and over a conventional platen imaging station 23 of the copier 10, using a friction belt platen transport system 32 overlaying the platen 23. In this example, documents are fed one at a time from the bottom of a stack placed in the tray 21 by a driven belt 33 to a roller set 34 which direct documents to driven rollers 28 and then to the friction belt transport system 32 for imaging. Documents input from the semi-automatic input are fed from the shelf 22 through rollers 35 to the platen 23. Documents exiting the platen transport system 32 are then directed via a decision gate (not shown) to either the lower two rollers 36 or the rollers 38. Documents fed from the semi-automatic shelf 22 are directed to an output tray 37 via the decision gate and rollers 36. Documents input from the tray 21 are directed by the gate to the rollers 38 from which they pass via a further decision gate 43 to either a pair of rollers 45 for feeding direct to the tray 21 or, if an inverting operation is required, to the lower pair of the three rollers 41. An inverted sheet can then be passed back to the tray 21 by the upper pair of the rollers 41. As apparent, the described arrangement of rollers provides for both simplex and duplex imaging of documents placed in the tray 21. A moveable cover 44, described in more detail later, is provided to cover the tray 21 during a document handling operation, the cover being mounted in guide means and adapted to be driven automatically back and forth, as indicated by the arrow A, in a horizontal plane above the document loading area of the tray 21. The document handler system has external covers 48, 50 to cover the moving parts which covers 48,50 are substantially contiguous with the cover 44 when it is closed. The exemplary copier 10 of Figure 1 is conventional, and need not be described. Conventionally, as disclosed above, the control of all document placement and feeding is by control unit 100, which is often a programmable microprocessor. A control unit of this type generally controls all functions of document handler system 20. The art readily teaches one to provide for a means and method to store and compare documents and copy counts to recognize jam signals, to implement time delays and the like through the control unit 100. Further, the control unit also controls all of the imaging and printing functions and steps of copier 10. A plurality of sensors S32, S33, S35, S36, S91 and S92 are provided in the RDH to detect document jamming. A sensor S34 is also provided to detect the presence of documents in the RDH and a sensor S37 is provided to count the documents. The outputs from these sensors are coupled to the control unit 100. Referring particularly to Figs. 3, 7 and 9, an arrangement is shown for mounting the cover 44 on the RDH. The cover 44 is provided along an edge with an extension piece 72 and, in the vicinity of its edge having the extension piece 72, is provided with two pairs of spaced rollers 80, 82. The rollers of each pair are spaced to accommodate therebetween an aluminium extruded guide rail or slide 78. The guide rail 78 may be fixed horizontally and parallel to the edge of the cover, with the rollers being in frictional engagement with the sides of the rail 78 for guided movement therealong. Referring also to Figs. 4A, 4B, 5 and 6, which show the cover drive mechanism in clearer detail, movement of the cover 44 is provided by means of a friction roller 84 mounted below the cover 44. The friction roller 84 together with a pulley 85 are coaxially mounted on a shaft 94, the roller 84 engaging with the undersurface of the cover 44. The roller 84 is kept in engagement with the undersurface of the cover 44 by urging means, in the form of a compression spring 92 (Fig 4B). The shaft 94, pulley 85 and roller 84 are mounted to one end of a supporting frame 97, which is itself supported and pivotally mounted to a bearing block 107. A drive shaft 95 of a bidirectional motor 90 is attached to the other end of the frame 97. The spring 92 is mounted to the end of the frame 97 carrying the roller 84, and urges that end of the frame 97 upwardly, thus forcing the friction roller against the underside of the cover 44. The pulley 85 is itself driven by a toothed belt 88 looped around both the pulley 85 and a drive pulley 86. The drive pulley 86 is mounted to the drive shaft 95 of the bidirectional motor 90 either directly or via a suitable gear train. The motor may have nominal operating conditions of 24 volts DC, 0.3 amps, 330 revs per min for a load of 0.11 Nm and the motor is selected to stall readily when the load exceeds a predetermined value. An exploded view of the RDH is shown in Fig 9 and illustrates the cover assembly comprising left hand upper and lower covers 50,112 and right hand upper and lower covers 48,116. Pairs of paper feed rollers mounted on respective shafts are also illustrated, and a pair of brackets 126, 128 for supporting the cover assembly. In operation the cover 44 starts (and is normally) in its first or open position, allowing documents to be loaded onto the tray. When the documents have been loaded in the tray 21, the operator presses a start switch or other control to initiate a normal operating sequence which leads to the feeding of the documents to the platen for imaging. This causes the control unit 100 to transmit firstly an actuating signal to energise the motor 90 which causes clockwise rotation of the drive pulley 86. The circuitry is arranged so that after the start button is pressed the motor 90 is energised to drive for a predetermined period, typically approximately 4 seconds. The clockwise rotation of the drive pulley in turn causes the friction roller 84 to rotate also in a clockwise direction. The underside of the cover 44 is in frictional contact with the friction roller 84 and it is driven in a horizontal direction over the tray until the forward edge of the cover 44 abuts against an opposite side wall of the right hand cover 48 of the RDH 20, at which point the cover has reached its second or closed position covering over the area above the tray. The cover 44 takes approximately two seconds to move from its open to its closed position. After the cover 44 has reached its closed position, a projection 102 provided on the underside of the cover 44 (see Fig. 5) engages with a projecting paddle 104 on the shaft 94 associated with the friction roller 84, thereby preventing the friction roller from further rotation. This in turn causes stalling of the motor, which nevertheless may remain energised for the further two seconds. After the 4 seconds have elapsed, the control unit 100 transmits signals to start the feeding of the documents from the tray area. After the RDH operations are completed, the control unit 100 then transmits a further signal to energise the motor 90, but for rotation in the opposite direction. The friction roller 84 now drives the cover 44 back into its first or open position in approximately 2 seconds. The paddle 104 on the shaft 94 associated with the friction roller comes into engagement with a further projection or lip on the underside or edge of the cover 44 (like 102), causing the friction roller to stop rotating and causing stalling of the motor 90, which nevertheless remains energised for a further 2 seconds. In this way, the document loading area is always automatically covered during the document feeding operations, thereby minimising noise from that area, but the document tray is also always automatically fully exposed for loading and unloading the documents. The need to sense the position of the cover 44 is eliminated by the above drive system, thereby obviating the necessity for cover position monitoring sensors. Furthermore, should an operator inadvertantly place their hand in the way of the cover during its closing operation, the motor 90 will automatically stall with low force, protecting the operator from injury. That is, the cover stops moving whenever a low predetermined resistance is encountered. (As an alternative, or in addition to the stallable motor, a low slippage force may be provided between the roller 84 and the cover 44, as the drive mechanism for moving the cover). Figs. 7 and 8 illustrate the cover 44 in more detail . The cover 44 is preferably thin, e.g. approximately 3 mm thick, and is in the form of a substantially rectangular sheet having a length of approximately 525mm and a width of approximately 275mm. The cover may be manufactured from a plastics material, such as polycarbonate, and has its end portion 77 angled downwardly. Along a portion of the rear of the cover is provided an elongate, substantially L-shaped, member 70 which is bolted over the rear edge of the cover 44 to act as a stiffener. The extension member 72 extends along a portion of one side edge of the cover 44. It will be appreciated that the invention encompasses other embodiments. For example, whereas the preferred embodiment above describes the use of just one guide rail 78, for the purpose of simplicity and cost effective construction, it is also possible to use two guide rails each disposed in proximity to respective longitudinal edges of the cover 44. Also the drive mechanism and friction roller, although described as being mounted below the cover 44, to reduce noise and efficient use of space, could in principle be disposed so that the roller engages the cover along its edge, or top surface. Likewise, alternative drive mechanisms could be utilized for reciprocating the cover, and the design of the cover can take different forms to that described above.

Claims: A document sheet feeding apparatus (24) including a document input tray (21) for receiving document sheets to be fed from the input tray (21) to be copied, a cover (44) arranged to be guided between a first position, in which the tray (21) is uncovered allowing document sheets to be loaded therein, and a second position in which the cover (44) covers the tray, characterised by drive means (90, 84) for automatically driving the cover (44) from the first position to the second position, and control means for controlling the drive means whereby the cover is automatically driven into the second position starting prior to the document sheets feeding from the tray. A document sheet feeding apparatus as claimed in claim 1, characterised in that the drive means is adapted to drive the cover back and forth between the first and second positions. A document sheet feeding apparatus as claimed in claim 2, characterised in that the drive means is reversible for reciprocating the cover between its first and second positions, the cover reaching each of its first and second positions when a respective side edge of the cover abuts against a respective datum surface. A document sheet feeding apparatus as claimed in any one of claims 1 to 3, characterised in that the drive means comprises a bidirectional motor. A document sheet feeding apparatus as claimed in any one of claims 1 to 4, characterised in that the drive means is adapted to stall with low force when a predetermined resistance is encountered. A document sheet feeding apparatus as claimed in any one of claims 1 to 5, characterised by a time delay associated with the control means for energising the drive means for a predetermined period prior to the start of any document sheet feeding from the input tray, said period being sufficient to ensure that the cover moves from its first position to its second position prior to the start of any document sheet feeding from the input tray. A document sheet feeding apparatus as claimed in any one of claims 1 to 6, characterised in that that drive means includes a low force drive motor (90) coupled to a frictional roller (84), the roller frictionally engaging the undersurface of the cover. A document sheet feeding apparatus as claimed in any one of claims 1 to 7, further including means for stopping the drive means when the cover has reached the second position. A document sheet feeding apparatus as claimed in any of claims 1 to 8, characterised by guide means (80, 82) for guiding the cover between its first and second positions, comprising an elongate guide rail (78) extending parallel and adjacent to at least one side edge of the cover. A document sheet feeding apparatus as claimed in claim 7, characterised in that a shaft (94) associated with the roller (84) carries a paddle (104) for engaging a projection (102) on the undersurface of the cover when the cover has reached its second position, said paddle and said projection cooperating to prevent further rotation of the roller after the cover has reached its second position, and further characterised in that the paddle on the shaft is also arranged to engage a further projection on the undersurface of the cover when the cover has returned to its first position, said paddle and said further projection cooperating to prevent further rotation of the roller after the cover has returned to its first position.

Inventors: BENDALL DENNIS MICHAEL, LOWMAN MICHAEL JOHN, BENDALL, DENNIS MICHAEL, LOWMAN, MICHAEL JOHN
Applicants: XEROX CORP, XEROX CORPORATION
Application year: 1995
Main classification: G03G15
IPC codes: G03G15