US Patent 7871142 Systems and methods for controlling ink jet pens

A control circuit is provided for controlling ink jet pens having different numbers of internal select lines using external select lines that extend between the control circuit and the ink jet pens and that are shared by the ink jet pens. In one embodiment, the control circuit includes a register that store values, the values indicating whether a pulse is or is not to be sent as to each of the external select lines, a first control module configured to control select pulses sent on a first external select line after consultation of the register, and a second control module configured to control select pulses sent on a second external select line after consultation of the register.