The present disclosure broadly relates to the art of printing systems and, more particularly, to at least a diverter assembly, a printing system including a diverter assembly, and a method of transporting sheet media.
Known printing systems commonly include two or more media transport paths that divert from one another at certain points and join one another at other points. Thus, a given sheet of media can normally be transported through a known printing system along any one of a variety of transport paths.
One example of printing systems in which such various transport paths are utilized are those printing systems having multiple marking engines. In such printing systems, sheets of media are selectively transported from a media supply to one of two or more marking engines. Thus, a diversion point is provided along the transport pathway at which one or more sheets of media will be directed toward one of the two or more marking engines.
Upon reaching the diversion point, a sheet of media will not itself select the appropriate media transport path along which movement of the sheet is desired. As such, mechanical diverters are typically provided immediately in front of the divergent transport paths to deflect the sheet along the desired pathway. One example of such a known mechanical diverter includes a gate that extends across the media transport path immediately in front of the diversion point of the transport path. The gate includes an upstream edge and a downstream edge, and is oriented along the transport path such that the downstream edge is pivotally supported at approximately the diversion point of the transport pathway. Thus, the gate creates a diagonally-extending blockage across the pathway that displaceable between first and second positions corresponding to sheet media diversion along the first and second transport paths.
In the first gate position, the leading edge of the gate is stationed away from or opposite the direction of the first transport pathway (e.g., stationed along the bottom of a horizontal transport path for diversion along an upwardly directed pathway), which thereby exposes a first side or surface of the gate. An incoming sheet of media will pass by the leading edge of the gate and contact the first side thereof, which will direct the sheet into and along the first transport path. In the second gate position, the leading edge of the gate is stationed away from or opposite the direction of the second transport path (e.g., stationed along the top of a horizontal transport path for diversion along a downward-directed pathway), which thereby exposes an opposing second side or surface of the gate. An incoming sheet of media will pass by the leading edge of the gate and contact the second side thereof, which in turn directs the sheet into and along the second transport path.
In operation, a printing system will transport sheets along the media transport pathway and frequently shift the gate between the first and second gate positions to selectively direct the transported sheets along an appropriate one of the first and second pathways. Commonly, a linear actuator, such as a spring-based solenoid, for example, will be operatively associated with the gate to switch the same between the first and second gate positions. One difficulty with such known arrangements, however, is associated with the continued demand for and corresponding advancement of the performance of printing systems (e.g., increased output in pages per minute). As the number of sheets transported through the pathways of a printing system increase, the number of corresponding gate switching operations is typically also increased. Thus, undesirable occurrences, such as impacts, vibrations and/or noise levels, for example, may become elevated due, at least in part, to these more frequent gate switching operations.
Another difficulty with known gate arrangements, which is also associated with the advancing performance of printing systems, involves the timing between the passing of a first sheet of media, the movement of the gate to a different position, and the arrival of a second sheet of media. More specifically, a given printing system will operate using a predetermined inter-document gap (IDG), which generally refers to the spacing between the trailing edge of a first sheet of media and the leading edge of a second sheet of media. However, as the output performance of printing systems continues to be improved, increasingly smaller inter-sheet gaps are expected to be used.
It is well known that the arrival of a second sheet of media at a diversion point prior to a gate reaching a desired gate position could result in the leading edge of the sheet of material contacting the upstream edge of the gate and thereby creating a jam or other undesirable condition. It will be recognized, them that as increasingly smaller IDGs are used, the time available for the gate to move from one position to the other is reduced. As such, the operating speed of the gate can be increased to maintain the desired operating. However, it is expected that a practical performance threshold will be eventually reached, above which only marginal increases gate switching speeds will be achievable using practical gate configurations (e.g., mechanisms of practical size or having a reasonable cost relative to the price point of the printing system).
One technique that can be used to increase the performance of known gate mechanisms involves initiating the switch between gate positions prior to the trailing edge of the first sheet clearing the upstream edge of the gate. However, while such techniques seem to work well at known printing system performance levels, as sheet media speeds increase and IDGs are reduced, the window for initiating the gate switch is reduced, Furthermore, care is normally exercised to ensure that that the upstream edge of the gate does not pinch or otherwise engage the first sheet of media, such as along the trailing edge thereof, and thereby undesirably slow or disrupt the movement of the sheet, This may be of particular concern where an advancement in the timing of the gate switching operations is being used to increase performance of the printing system.
Accordingly, it is believed desirable to develop a diverter assembly, printing system and method that overcomes the foregoing and other problems and difficulties.