Xerox 4450 - Manual (Page 57)

TROUBLESHOOTING
The hardware limitation of 320 dispatchable items per 300 spi
scan line (640 for 600 spi) includes the required overhead of two
dispatchable items. For example, a dispatchable item could be a
maximum of 32 dots wide for 300 spi (64 dots for 600 spi), and
thereby might be a full character (less than point size 8 or 9), a
fraction of a character (greater than point size 8 or 9), or a line
segment that is equal to or smaller than 32 dots in the scan
direction.
Determining line density limitations The following is a guide for determining 300 spi line density
limitations. If printing at 600 spi, the same size character or same
length line has twice as many dots, as follows:
• Every 32 dots (or fraction thereof) of a line drawn on the
long axis of the paper are one dispatchable item.
• Each line drawn on the short axis of the paper is one
dispatchable item.
• Each active character is at least one dispatchable item. (An
active character includes all the space from the top of the
character cell to the bottom of the character cell, even if
there is only white space present on a given scan line.) If the
dimension along the scan line is greater than 32 dots, the
character consists of some multiple dispatchable items.
It is not possible to construct a form with two adjacent lines if
both use the full count of 318 dispatchable items (320 minus the
two required for overhead) resulting from text and lines. The
imaging system requires a rest period of about four scan lines
before it can image the second fully loaded line.
Landscape pages Line density restrictions differ as a function of the mode
(landscape or portrait) of the form. An 8-point or smaller
landscape font is smaller than 32 dots for 300 spi and 64 for 600
spi. A vertical line is a single dispatchable item. A horizontal line
is treated as a series of 32 dots in length, joined end-to-end.
For 300 spi, this means that a form using an 8-point or smaller
font on a landscape page may have up to 318 characters (plus a
two-item overhead, for a total of 320 dispatchable items) on a
scan line. For example, when using a 6-point font, it is possible
to have 132 characters, a line across the page under the text, and
up to 90 vertical lines, without exceeding the line density
limitations.
If a form requires a 9-point or larger font, the number of
characters that may be imaged on a landscape page is reduced to
160 because the characters are generally more than 32 dots
wide. While the dispatchable-item count remains 320 per line,
fonts 9 points and larger use two dispatchable items per
character. Since a character in a large font constitutes two
dispatchable items, only half as many characters in a large font
may be imaged on a scan line as is possible with a smaller font.
Portrait pages Restrictions for a portrait page are significantly different from
those for a landscape page because the system always images in
the landscape direction. Therefore, if a page is formatted in
portrait orientation, the hardware must reorganize the data into
landscape prior to imaging.
XEROX 4050/4090/4450/4650 LPS FORMS CREATION GUIDE 4-7