When you print a file on the Imagewriter, sometimes the first printed line at
the beginning of the paper is crunched or expanded. This problem sometimes
occurs after you take the paper out of the platen: you may have left the
tractor gears in a position "between linefeeds". Solve this problem by doing a
form feed right every time you reload the printer with paper.
Sometimes the paper is not held tight enough by the rollers, especially when
you use cut sheets. Solve the problem by "burping" the printer: turn the
printer off and on so the printhead moves back and forth and the gears are
tightened.