Specifications

Table Of Contents
^CO
Cache On
Description: The ^CO command is used to change the size of the character cache.
By definition, a “character cache” (from here on referred to as cache) is a portion of
the DRAM reserved for storing scalable characters. All printers have a default 22K
cache that is always turned on. The maximum single character size that can be
stored, without changing the size of the cache, is 450 dots by 450 dots.
There are two types of fonts used in Zebra printers: bitmapped and scalable. Letters,
numbers, and symbols in a bitmapped font have a fixed size. For example: 10
points, 12 points, 14 points, etc. On the other hand, scalable fonts are not fixed in
size. Their sizes are user-selectable.
Because their size is fixed, bitmapped fonts can be moved quickly to the label. By
contrast, scalable fonts are much slower because each character is built on an
as-needed basis before it is moved to the label. By storing scaled characters in a
“cache” they can be recalled at a much faster speed.
The number of characters that can be stored in the cache depends on two factors: the
size of the cache (memory) and the size of the character (in points) being saved. The
larger the point size, the more space in the cache it uses. The default cache stores
every scalable character that is requested for use on a label(s). If the same character,
with the same rotation and size is used again, it is quickly retrieved from the cache.
It is quite possible that after a while the print cache could become full. Once the
cache is full, space for new characters is obtained by eliminating an existing
character from the print cache. Existing characters are eliminated by determining
how often they have been used. This is done automatically. For example, a 28 point
“Q” that was used only once would be a good candidate for elimination from the
cache.
Maximum size of a single print cache character is 1500 dots by 1500 dots. It would
require a cache of 300K for this.
When the cache is too small for the desired style, smaller characters may appear but
larger characters will not. If possible, increase the size of the cache.
ZPL II Programming Guide Volume One: Command Reference for X.10
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