Abstract: An improved system for determining the optimal phase time to charge a liquid stream emitted from a jet as it evolves in form from a continuum to a separatuum of droplets wherein the optimal time for achieving the desired level of charge on a given droplet may be had by applying the charge immediately prior to break-off of droplets. A particular use of the system is in an ink jet droplet apparatus having a controlled liquid stream of ink that is separated into droplets by a sonic transducer and then charged by a pair of charging plates in a dynamically controlled manner at an optimal phase time as correctably tested by the system for subsequent static deflection of the charged droplets to a desired portion of a document to form printed characters.

Abstract: A laminar air flow passageway through which ink droplets are directed before striking a moving print medium, having a portion of the passageway contoured to expand toward the print medium for slowing a column of air passing therethrough before the column reaches the document. Air suction apertures located in the expanded portion of the passageway and near the print medium provide withdrawal of the airflow to prevent air buildup at the document interface and to maintain laminarity as the air slows. A separate embodiment includes a single air suction aperture located in the upper portion of a gently expanding air passsageway for airflow withdrawal.

Abstract: An improved character reading system that utilizes two separate read devices: a first read device and a second read device in combination with a random access memory for storing each character read by the first read device, a memory control circuit for writing each character into the random access memory, and a comparison logic circuit for comparing each character as read by the second read device with the corresponding character stored in the random access memory. The system also includes a time-out counter for indicating when the last character has been read and a comparison logic timing circuit for controlling the comparison logic and triggering the random access memory read control circuit so as to provide the corresponding character to the comparison logic.