Printronix Online Data Validator - Manual (Page 85)

Print Speed Limits
85
Operation
There are a number of factors which contribute to successful bar
code validation, including printer speed, on-demand print settings,
calibration, and ambient light. The following sections describe how
to ensure your bar code validator is scanning and reporting
properly.
Print Speed Limits
Two factors in the validation process affect the printer’s speed limit:
minimum code height (bar code height) and minimum code gap.
The printer automatically examines the Min. Code Height and Min.
Code Gap values and sets the defined maximum slew (vertical
paper movement) and print speeds to insure proper operation. If
the current Print Speed and/or Slew Speed values in the MEDIA
CONTROL menu are higher than the newly defined maximum, the
values are changed to equal the maximum. If the current values are
lower than the newly defined maximum, no change in speed
occurs.
Min. Code Height (Bar Code Height)
The validator cannot function at the highest speed possible by the
printer. It requires a minimum number of scans per bar code to
make a reliable assessment, so the speed of the printer is limited
by the height of the bar code. If the bar code is very short, printing
needs to be slowed down to allow sufficient scans to occur. If the
print speed exceeds this limit, the message Speed Exceeds
Validator Limit will display. Print speed will be lowered automatically
if required, but will not automatically reset to a higher speed.
The printer cannot predict how high all the bar codes in a given job
will be, so it cannot automatically limit or adjust the print speed to
insure the code height/speed requirement is being met. When the
bar code is too short for the selected speed, the printer produces a
missing bar code error condition. Therefore, printer speed must be
set manually to compensate for bar code height.