Abstract: Apparatus for producing updated information on a tangible medium including a hand-held type instrument having an optical character reader to read present information on the medium, a programmable bus-oriented computing type network, spaced from the instrument, which stores and compares the updated information with the present information being read and which outputs control words corresponding to the updated information if the updated information is different from the present information, and an ink jet printer, included in the hand-held type instrument, which prints the updated information on the medium in response to the control words. The computing type network can include a micro-computing unit which can be a microprocessor, for example, and memory units which can be RAM, ROM, etc.