Tektronix PHASER 380, Service Manual

Page: 308 / 346

9-28
Phaser 380 Color Printer
9
Checks and Adjustments
Adjusting scale and skip factors
Scale adjustment compensates for gain error in the x-axis drive mechanism. If
not properly set, the printhead will not travel far enough or will travel too far as
it performs its short, lateral movement to “print” the image on the drum.
Due to jet interlacing, traveling an incorrect distance actually results in a series
of dark lines or light lines where the adjacent jets produce lines that are to close
or too far from neighboring lines. You make scale adjustments for printing
single-scan, A-size images (Scale Factor A) and for double-scan, B-size images
(Scale Factor B).
Tools needed
■
Magnifying loupe
Figure 9-16 Concept of scale adjustment
9661-166
Too little gain
Correct gain
Too much gain
Gain exaggerated
for clarity