Calibrating a bi-directionally scanning electrophotographic device

Methods and apparatus include aligning printing of a bi-directionally scanning electrophotographic (EP) device, such as a laser printer or copy machine. At least first and second scan lines formed in opposite directions define a calibration page for manufacturing, servicing or end-user operation. The page includes pluralities of objects with one formed from either the first or second scan lines, but not both, and another of the objects formed from the other of the first or second scan lines, but not both. In this manner, corrections can be implemented by simply observing misalignments between the objects. Printed calibration pages also include visually or mechanically read objects for implementing corrections. In this regard, calibrating devices external to the EP device are contemplated. Objects include lines, squares or other shapes and their arrangement on a page varies. Fiducials for macro-scale observations are also contemplated.