Attachment systems and associated structures are configured to provide accurate installation, removal and reinstallation of modular print bars in a printing system. An exemplary attachment system comprises one or more matched attachment assemblies, comprising latches and pins, wherein the latches are fixedly arranged with respect to print bar bays, and wherein each of the print bars is slidable with respect to a corresponding print bar bay. When a print bar is alignably positioned with respect to a corresponding print bar bay, a corresponding pin is securable to the latch, to accurately affix the print bar with respect to the print bar bay. The attachment system provides repeatable and accurate registration of the print bar with respect to the printing system. The enhanced attachment system may preferably comprise comprises an actuators, e.g. pneumatic or electric, to controllably engage or disengage the pins and/or latches.