Check-digit printing means

In a document printer with means for feeding successive documents to be successively serial-number printed in successive printing cycles, said printer including a sequentially indexible numerical print had and means synchronized with the printing cycle for numerically indexing said head in predetermined equal successive increments from one to the next printing cycle, the improvement which comprises indexible check-digit print means carried by said printer and including means synchronized with said printing cycle for check-digit imprinting of each successive document in accordance with the indexed position of said check-digit print means, and further means synchronized with said printing cycle for changing the indexed position of said check-digit print means in accordance with each successive index increment required by a particular weighted-modulus system of computing check-digits, said further means including a basic unitindexing drive for said check-digit printing means, a plurality of control devices having control connection to said drive and settable uniquelly for each digit position within the serial-number capacity of said print head, said control devices being preset to determine different integer-multiple control of said unit-indexing drive in accordance with the requirements of the particular weighted-modulus system, and counter means responsive to the instantaneous serial-number setting of said print head and determining which digit position of the serial number undergoes a single-digit change other than to zero for each successive printing cycle, said counter means producing for each printing cycle an output connection to that particular control device which is uniquely set for the particular digit position undergoing the single-digit change other than to zero.

In a document printer with means for feeding successive documents to be successively serial-number printed in successive printing cycles, said printer including a sequentially indexible numerical print head and means synchronized with the printing cycle for numerically indexing said head in predetermined equal successive increments from one to the next printing cycle, the improvement which comprises indexible check-digit print means carried by said printer and including means synchronized with said printing cycle for check-digit imprinting of each successive document in accordance with the indexed position of said check-digit print means, and further means synchronized with said printing cycle for changing the indexed position of said check-digit print means in accordance with each successive index increment required by a particular weighted-modulus system of computing checkdigits, said further means including a basic unit-indexing drive for said check-digit printing means, a plurality of control devices having control connection to said drive and settable uniquely for each digit position within the serial-number capacity of said print head, said control devices being preset to determine different integer-multiple control of said unit-indexing drive in accordance with the requirements of the particular weighted-modulus system, and digit-change sensing means responsive to the instantaneous serial-number setting of said print head and determining which digit position of the serial number undergoes a single-digit change other than to zero for each successive printing cycle, said digit-change sensing means producing for each printing cycle an output connection to that particular control device which is uniquely set for the particular digit position undergoing the single-digit change other than to zero.

In a document printer with means for feeding successive documents to be successively serial-number printed in successive printing cycle, said printer including a sequentially indexible numerical print head and means synchronized with the printing cycle for numerically indexing said head in predetermined equal successive increments fron one to the next printing cycle, the improvement which comprises indexible check-digit print means carried by said printer and including means synchronized with said printing cycle for check-digit imprinting of each successive document in accordance with the currently indexed condition of said checkdigit print means, said check-digit print means having a cycle of different indexed conditions corresponding to the modulus number required by a particular weighted-modulus system of computing check digits, said check-digit print means having the capacity to print a particular one of a plurality of different check digits for each indexed condition thereof, and further means synchronized with said printing cycle for changing the indexed condition of said check-digit print means in accordance with each successive index increment by the particular weighted-modulus system of computing check-digits, said further means including indexing-drive means for said check-digit printing means, a plurality of control devices having control connection to said drive means and settable uniquely for each digit position within the serial-number capacity of said print head, said control devices being preset to ddetermine different check-digit increments of indexing control of said indexing-drive means in accordance with the requirements of the particular weighted-modulus system, and means responsive to the instantaneous serial-number setting of said print head and determining which digit position of the serial number undergoes a single-digit change other than to zero for each successive printing cycle, said last-defined means producing for each printing cycle an output connection to that particular control device which is uniquely set for the particular digit position undergoing the single-digit change other than to zero.