HP 250C - Manual (Page 193)

230
250C
330
350C
8Ć59 Troubleshooting C4699Ć90000
VerticalĆLine Straightness (VLS)
Symptoms
VerticalĆline straightness is a measure of the horizontal distance between the segments of a
vertical line plotted in two consecutive swaths. If the plotter is working correctly, this
distance should be less than 2 mils. (PrintĆQuality Plot ' page 8Ć56
3. - VLS
.)
(See also ' User's Guide, chapter 4.)
Swath Printing Direction
Maximum allowable VLS Error = 2 mils.
Swath (n–1)
Swath (n)
Swath (n+1)
Swath Printing Direction
Swath Printing Direction
Depending on the causes of the error, lines that are supposed to be vertical may appear as
shown below:
Combined error
Swath W
idth
Swath W
idth
Swath W
idth
Swath W
idth
Carriage Swath
Direction
1 2 3a 3b 4a 4b
1 No error
2 Bidirectional error
3a Theta–Z error
3b Theta–Z error
4a Combined error
4b
Customer Expectations
Although the VLS specification satisfies the expectations of most customers, some may
complain even when the plotter is working within this specification. If the VLS error is
already less than 2 mils, do not try to improve it.
Bidirectional Error
Error numbered 2 above is called a bidirectional error. If you print the same plot using a
unidirectional print mode, the error should not appear. (Print modes ' chapter 5.)
This error can occur for various reasons, including:
D Incorrect distance between nozzles and media. (Adjustment ' chapter 7.)
D EncoderĆstrip slots are damaged or dirty.
D Dirt on the pulley is causing the belt to slip.
D Friction between carriage bushings and slider rod:
(See ' Error code
Steady 346
.)
(See ' Error code
Steady 234
.)