Ink jet printer

Claim 1

An ink jet page printer comprising: a source of ink (201); one or more print heads (7) each comprising a plurality of jets (55) and a corresponding plurality of actuators (62) responsive to electrical signals for selectively projecting droplets of ink; a transfer medium (1) having a moving surface (16) thereof adjacent to but spaced apart from said print head (7) for receiving said projected droplets; circuitry (902) for generating said electrical signals for controlling said print heads to create patterns of droplets of ink on said moving surface (16) said circuitry comprising a memory (908) for storing indicia representative of patterns of droplets of ink to be projected on said moving surface (16), a means (906) for writing indicia into said memory in response to received input signals, a means (910) for reading indicia from said memory and means (913) for controlling said printing heads (7) in accordance with said indicia read from said memory; an arrangement (12, 203 to 207) for selectively transferring the droplet patterns from said transfer medium surface (16) to a printing medium (23), said arrangement comprising a printing medium support surface (11) and a printing pressure roller assembly (12, 204 to 207) for pressing a printing medium (23) supported on said support surface into line contact with said transfer medium surface (16) when enabled, and means (203) for selectively enabling said printing pressure roller assembly; a printing medium feed assembly (208) for storing a plurality of sheets of printing medium (23) and for moving said sheets one at a time to said printing medium support surface (11) in timed sequence with the operation of said printing pressure roller assembly (12, 204 or 207); means (81, 921) coordinated with the movement of said moving surface for generating control signals for said circuitry (902) said means coordinated with the movement of said transfer medium moving surface (16) comprising a timing track containing optically or magnetically discernible indicia (81) disposed on said surface (16) and means (921) for generating control signals in response to said discernible indicia; lateral motion means (8, 9, 10, 51) for controlling moving said print heads (7) in a first direction transverse to the direction of travel of said transfer medium moving surface (16); means (8) for controlling said lateral motion means to move said print heads (7) in coordination with the movement of said transfer medium such that each ink jet (55) successively serves the tracks of a plurality of adjacent parallel tracks on said transfer surface (16); means for controlling said lateral motion means to move said print heads in a direction opposite to said first transverse direction so as to position said ink jet over the first track of its plurality of tracks; and an arrangement (13) for cleaning said transfer medium (16) surface after the droplet patterns have transferred from said transfer medium surface to said printing medium (23), said arrangement (13) including a roller (17) for pressing a cleaning medium (14) into contact with the transfer medium surface (16) when enabled, and means (209) for selectively enabling said cleaning arrangement (13).