HP 220 - Manual (Page 144)

7Ć6 Calibrations C3187Ć90000
Accuracy Calibration
Purpose
The accuracy calibration procedure is used to correct the endĆpoint accuracy of the media
axis. The cartridge axis does not require calibration and is used to calibrate the media axis.
Perform the accuracy calibration whenever the:
D EEROM is erased
D Main PCA is replaced
D Drive roller is removed or replaced
D Media (XĆaxis) motor is replaced
What is the EndĆPoint Accuracy Specification ?
The endĆpoint accuracy specifies how accurately a plotter can draw a given length of line.
The endĆpoint accuracy specification for the plotters is ± 0.38 mm (0.015 in) or ± 0.2% of the
specified vector length, whichever is greater, at 23 d C (73 d F), at 50Ć60% relative humidity on
HP special polyester film. Use the following formula to calculate the plotter's accuracy:
Measured length – Desired length
Desired length
x 100 = %Error
What can Affect the EndĆPoint Accuracy ?
Various part tolerances inside the plotter affect the accuracy (in particular the drive roller).
Other outside influences include:
D Mediathickness. Thicker mediacreates longer lines.
D Mediaexpansion. As the mediagrows, so do the lines.
D Application software. The software may be instructing the plotter to draw an incorrect
line length.
D The EEROM has been cleared. The accuracy constants are stored in this nonĆvolatile
memory component.
(Further information D chapter 5, w MediaĆDrive Accuracy.)