Normal Interlace Processing (360Dpi; General - Brother MP-21C Service Manual

CHAPTER II
1.

GENERAL

1.1

Normal Interlace Processing (360dpi)

Fig. 2.1 below shows the relationship between the printing area and the line feed amount
for each print head pass.
pass 4
pass 1 (Position to start printing)
Area covered by
the printing head
The printing operation is performed by repeating the following sequence:-
(120/1440 line feeding + 32 nozzle printing + 124/1440 line feeding + 32 nozzle printing +
124/1440 line feeding + 32 nozzle printing + 124/1440 line feeding + 62 nozzle printing +).
A buffer stores the data for each pass and interlace tables indicating how to allocate the
raster data for each pass are used for the printing operation.
To which pass (storing buffer) the binary raster data is loaded sequentially is allocated
and is initially determined according to the interlace table.
4 rasters of color print data and 1 raster of monochrome print data are converted to raster
graphics transfer commands (G/Z) and stored in the buffer. After the above conversion,
TIFF compression or mirroring is performed if necessary.
The number of rasters handled by each interlace table corresponds to the line feed
amount. Rasters are handled sequentially and the buffer store for sending commands for
1 pass is generated when the last raster of each table (the 1st raster of the next table in
normal and draft modes) is reached. Therefore, once data in the buffer is sent to the
printer with the line feed command (F), the buffer is initialized so that it will be ready for
use for later passes and processing of the next raster starts in the same manner.
THEORY OF OPERATION
pass 2
pass 3
pass 4
pass 1
pass 2
Interlace table 1
Interlace table 2
Interlace table 3
Interlace table 4
Fig. 2.1
II-1
(Line feed amount)
124/1440
124/1440
124/1440
124/1440