Output image processing for small drop printing

Abstract

A method of forming a liquid pattern according to liquid pattern data on a receiving medium using a liquid drop emitter that emits a continuous stream of liquid from a nozzle that is broken into drops of predetermined volumes by the application of drop forming energy pulse is disclosed comprising associating a pixel area of the receiving medium with a nozzle and a time interval during which a plurality of fluid drops ejected from the nozzle can impinge the pixel area of the receiving medium. The time interval is divided into a plurality of subintervals that are, in turn, grouped into a plurality of blocks. Each block is defined as a printing block or a non-printing block. A drop forming energy pulse is provided between each pair of consecutive blocks and between the subintervals of each printing block. No drop forming energy pulses are provided between the subintervals of the non-printing blocks. The so-formed energy pulse sequence is applied to the stream of liquid causing the formation of small print drops and large non-print drops. The liquid pattern is formed on the receiver of print drops comprised of liquid emitted during subintervals associated with printing blocks. The block configuration is designed to ensure that non-print drops have the proper volume. In an alternate set of embodiments, individual subintervals rather than blocks of subintervals are individually defined as print or non-print subintervals subject to a non-print drop rule that forces non-print drops to be formed of adequate volume for differentiation from print drops and a maximum drop rule that ensures that non-print drops are not too large to be reliably captured and guttered.