Apparatus and method for reproduction of character matrices ink jet printer using read only memory

Claim 1

In an ink jet recorder of the type wherein two spaced rows of laterally staggered ink jets are stimulated to produce streams of uniformly sized and regularly spaced drops, and said drops are selectively charged for deflection and catching to produce printed matrices corresponding to characters selected from a set thereof, apparatus for controlling said matrix printing comprising: a read only memory organized into sections corresponding to said characters, each section thereof being directly connected to input lines greater in number than the number of rows of said matrices and to output lines equal in number to the number of columns of said matrices, means for organizing laterally consecutive jets into a plurality of groups with each group membership corresponding in number to the number of output lines from one of said memory sections, switching means for placing each of said groups into communication with the output lines from any one of said sections, means for sequential activation of the input lines of any of said memory sections, means within each of said sections for connection of the section input lines to some of the section output lines whereby said sequential activation of the input lines of any of said memory sections communicates to charging means for jets within one row of a communicating jet group a set of parallel information signals corresponding to marking information in corresponding columns of the corresponding character matrix, other means within each of said sections for connection of the section input lines with other of the section output lines whereby saiD sequential activation of said section input lines communicates to charging means for jets within the other row of said communicating jet group another set of parallel information signals corresponding to marking information in other columns of the corresponding character matrix; said other set of parallel information signals being delayed with respect to the first aforesaid set of parallel signals an amount of time corresponding to the spacing between said other row of jets and the first aforesaid row of jets, a register connected to each of said memory sections and organized for bytewise receipt of said parallel information signals, shifting of bytes so received in synchronism with said sequential activation, and temporary storage of one marking control signal for each jet in said recorder, and means to transport a mark receiving member past said drop streams at a speed whereby the sets of parallel signals communicated to the charging means for said rows of jets produces deflection and catching of drops within said streams with row to row delays as required to reproduce said character matrix in correct registration.