Apparatus for grey level printing using a binary architectured printhead

Claim 1

A non-impact recording apparatus comprising: a binary architectured printhead including a) a plurality of recording elements; b) a respective register means associated with each recording element for storing a single image data bit and cooperating in activating a respective recording element for a predetermined enablement time as determined by a strobe pulse; c) means including a plurality of independent enable lines for carrying a plurality of strobe timing pulses; d) an enabling means for enabling a recording element in response to a data bit stored in a respective register means and to a strobe timing pulse; e) means for coupling a plurality of recording elements to one of said enable lines and a different plurality of recording elements to another one of said enable lines; and f) driving means for driving said binary architectured printhead to record grey level pixels using plural sub-lines to record each grey level pixel; said driving means including a) means for generating a new set of sub-line binary data signals for each sub-line of recording and for conveying such signals to the printhead for storing in a plurality of respective register means; and b) means for generating on each enable line a repeating series of strobe timing pulses, the series of pulses being a set of timing pulses of different durations for use in recording a grey level pixel, a pulse from the set of timing pulses being generated during a sub-line exposure period on each enable line and each enable line having a pulse from said set of timing pulses generated thereon that is a different duration that that generated on another enable line during said sub-line recording period and wherein during a sub-line exposure period pulses on the enable lines are substantially nonconcurrent.

Claim 4

The apparatus of claims 1 or 2 and wherein a sum of strobe pulse durations on three of the enable lines during a sub-line recording period is less than a duration of a strobe pulse on a fourth enabling line during said period.

Claim 6

The apparatus of claims 1 or 2 and wherein there are a plural number N of recording elements per inch in a main scanning direction and control means are provided for moving a recording medium relative to said recording elements for generating new sub-lines of data for recording on said recording medium at a rate of P sub-lines per inch, wherein P is larger than N.