Ink jet print head identification circuit with serial out, dynamic shift registers

摘要

An ink jet print head identification system for providing print head identifying information to the electronics of an ink jet printer includes one or more parallel load, serial out, dynamic shift registers (50 A-D) integrated into a print head chip having a plurality of address lines interconnecting the printer electronics and print head electronics. Each shift register is programmed or encoded with a single digital bit. In one embodiment, a voltage pulse (load signal) (70) received on a single chip address line by a plurality of shift registers (50 A-D) loads the input of each encoded register with the register's own encoded bit. Two of the address lines (72,74) provide each of the registers with successive sequential clock signals (1,2) to serially shift the encoded information to an output device (80) where the print head identifying information is read by the printer electronics. Other embodiments of the invention may employ any number of encoded registers independently of the number of available address lines. <IMAGE>