Patent ID: 6848765

Claim:
Apparatus for printing images, by marking with a liquid-base ink, on a web-form printing medium that has a longitudinal direction and two lateral edges; said apparatus comprising: means for supporting such medium; a marking head disposed for marking on such medium; means for engaging such medium and for advancing such medium longitudinally past the marking head; first guide means for restraining such medium, over an area that is: upstream, longitudinally, from the marking head, and extended laterally across substantially a full width of such medium except in one or more regions that are laterally near the engagement of the engaging-and-advancing means with such medium; second guide means for restraining such medium, over an area that is: disposed laterally from the marking head, and extended laterally across such medium only in one or more regions that are laterally near the engagement of the engaging-and-advancing means with such medium; means, longitudinally beyond the marking head from the advancing-and-engaging means and generally aligned laterally with the advancing-and-engaging means, for tensioning such medium away from the advancing-and-engaging means to hold such medium substantially taut at the marking head; wherein such printing medium, when tensioned between the advancing-and-engaging means and the tensioning means, moves stepwise through the apparatus at a normal distance of advance in each step; and further comprising: means for sensing when a longitudinally rearward edge of such printing medium passes the advancing-and-engaging means so that such printing medium is advanced only by the tensioning means; and means, responsive to the sensing means, for decreasing the distance of advance through the apparatus in each step while such printing medium is advanced only by the tensioning means.