Accuracy Calibration - HP C2858A Service Manual

ACCURACY CALIBRATION

Performance of these accuracy procedures allow you to either restore the plotter to the facto-
ry accuracy settings or to recalibrate the plotter to the current environment. Accuracy calibra-
tion constants are stored in the plotter EEROM. When performing the accuracy calibration
from the "Service Test" menu, the factory correction value will be recalculated. This will be
the new factory default calibration value. The calibration performed from the "Utilities"
menu will calculate a new user calibration value. This value will override the factory value
until the plotter is reset from the "Resets" submenu. Once reset, the plotter will use the factory
default until another user calibration is run.
Check the accuracy calibration whenever the:
D
D
D
Before performing an accuracy calibration, run a configuration plot. An accuracy calibration
is needed if the distance between the centers of the "X" marks on the configuration plot is not
500 mm (20 in.) 1 mm (0.04 in.) under normal environmental conditions. Media expansion
and thickness can affect endpoint accuracy. The plotter endpoint accuracy is specified on ink-
jet polyester film only, at 0.2% of the specified vector length.
If the measured accuracy, media thickness, or environmental conditions vary greatly from
the factory standards, recalibrate the plotter using the following procedure.
To perform the accuracy calibration, use the following steps:
'User' and 'service' accuracy calibration procedures are similar. Follow the
appropriate 'user' or 'service' noted paths in the steps.
1. Place a sheet of media over the top of the plotter for 10 minutes to let it stabilize to the
environmental conditions. Use a sheet approximately 24 x 36 inches (61 x 91 cm).
Roll media may also be used. Use polyester film when performing the Accuracy
Calibration from the "Service" menu. If using inkjet polyester film, load the film
with the matte (dull) side down.
2. Load the media. If using D-size media, load the short edge as the leading edge in
C2858A plotters and the long edge as the leading edge for C2859A plotters. The
C2859A can also use E-size media. Both plotters can use polyester film roll media
for this procedure.
Adjustments/Calibrations
7-4
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EEROM IC is replaced or erased
platen (drive) roller is replaced
X axis motor/encoder is replaced
Note