<p>I have a few (4) HP 4480 all-in-one printers, and plan on attempting to reverse engineer the flex cable that goes to the printhead controller, not the printhead itself.</p>
<p>I have already determined the optical encoder’s pinout, and it looks like most of the rest is matrix signalling at logic levels that goes to a voltage buffer ASIC on the printhead controller carriage.</p>
<p>With luck, that could radically simplify the control of the printhead, and reduce part count (since I’ll be able to re-use the on-carrier printhead controller and logic to 30v voltage buffer).</p>