Abstract: A media position sensing system for a plotter in which a media is driven along at least one edge thereof comprising a plurality of apertures in the media positioned within the width of the edge and an optical detector positioned along the edge for sensing the appearance of the apertures in order to sense a selected position of the media. In a particular embodiment, the width of the apertures are less than one-half the width of the edge and are offset spaced from one another across the width of the edge to present an effective detection capability equivalent to a single aperture having a width equal to the width of the edge. The apertures extend along the length of the media a distance approximately equal to the width of the edge and are located near the end of the length of the media for sensing the end of the media.

Abstract: Apparatus and an associated method for ascertaining the operational status of a pen in a vector plotter in which a pen is moved into contact with a paper web at a test location, the pen is moved relative to the web and an optical detector is used to determine whether or not the pen is drawing a line on the web. The web is moved from a supply roll to a take-up roll to move the test area on the web to an optical testing location. The absence of a line after a pre-determined period of web movement time signals the inoperative status of the pen and the detection of a line by the pen within that pre-determined period of movement time signals that the pen is operative. Quality and proper line width of the line can also be determined.

Abstract: In a pen plotter having a pen carriage exchangeably carrying a pen with a downward-facing plotting tip controlled in its movement over a plotting area by control logic and also having a multiple pen-holding rotating turret hub controlled by the control logic, this invention consists of cleaning apparatus for automatically cleaning the tip of a pen after pickup from the turret hub and prior to or just after use. There is a brush ring having upward-facing bristles concentrically carried by the turret hub and additional logic contained in the control logic for moving the pen carriage to the brush ring to place the plotting tip within the bristles prior to or just after plotting with the plotting tip and for rotating the turret hub and the brush ring in combination when the plotting tip is within the bristles whereby to clean the plotting tip with the bristles. The brush ring can be rotated bi-directionally for better cleaning if desired.

Abstract: This is an apparatus and associated method for rolling large pieces of a flexible media such as completed plots produced by a plotting pen plotter. The rolling mechanism is placed adjacent an exit of the pen plotter to received ejected media pieces therein. Upon detecting the leading edge of a media piece while in an open position, the mechanism closes to form a guide slot to a cylindrical rolling chamber. The media piece is then urged along the guide slot and into the rolling chamber where it is rolled by a drive roller. Upon detecting the trailing edge of the media piece, the mechanism opens allowing the rolled media piece to fall into a receiving bin. The stationary portion and the rotating portion are formed of a plurality of slats having low contact area edges disposed for media pieces to move along whereby the media pieces move along a low friction path.