DataCard CP60 Service Manual page 25

Strobe
If an entire column of thermal elements (pixels) needs to be activated, the overall
power to the printhead will drop due to the current draw. The strobe setting
compensates for this drop in voltage by increasing the time that the pixels are
active.
For example, if all 672 pixels were turned on, it would take longer for each pixel
to reach the threshold temperature than it would if only 300 pixels were turned
on. This would result in a lighter image if more pixels are needed, and a darker
image if only a few pixels are needed.
The Strobe setting is a time factor that compensates for this reduction in power
by increasing the "on-time" for each pixel based on how many pixels are required
for the printed column. The strobe setting value is a baseline number for a
look-up table that the printer calculates for each printed column.
The gray test card is used to detect strobe misadjustment. This test card is
available only to the Advanced User in Diagnostics.
CP60 and CP60 Plus Service Manual 2-13