Hewlett-Packard Co. promoted Martin Fink Thursday to chief technology officer and director of its research unit, HP Labs. Fink is a 27-year veteran of Palo Alto-based HP (NYSE:HPQ) and most recently ran its business critical server business. The CTO job was last held by Prith Banerjee, who left in April to become tech chief at Swiss automation and power company ABB. HP Senior Fellow Chandrakant Patel ran HP Labs in the interim and has been named chief engineer. Ric Lewis will now be interim head…