Electronic Print Position Indicator And Margin Scale Indicator For Interactive Ink Jet Printers
Original Publication Date: 1979-Dec-01
Included in the Prior Art Database: 2005-Feb-20
In the IBM SELECTRIC the print position indicator (PPI) comprises a hairline on a card guide mounted on the carrier. Because of the separation of the carrier and card guide from the paper, an accurate indication of print position is sometimes difficult because of parallax. In interactive ink jet printers, the carrier drives conventionally have a larger tolerance in stopping distance. For example, the stopping distance of the carrier after a stop command may vary 7 to 8 units (a unit equals approximately 1/60"). For reference purposes, a 10 pitch character is 6 units. Thus, with an interactive ink jet printer, a meaningful PPI should be more than a hairline. A similar, though perhaps less critical problem exists with the margin scale indicator (MSI).