Canon multipass c3000 Service Manual (en)

2.3 Data Flow
1) Interface
Character codes, control codes, and image data conforming to the printer's character table
are sent to the interface from the computer.  The data are received when the printer is in
on-line standby, or when the carriage changes directions during printing.
2) Input buffer
Data received from the interface are stored in the printer DRAM's built in  input (reception)
3) Data analysis and printer buffer
The MPU analysis the data stored in the input buffer, and printing image data for each
nozzle of the BJ cartridge are stored in the printer DRAM's built-in print buffer.
If there are character data, the Control/CG ROM font image data are stored in the print
buffer.  Control codes are used for switching print modes, etc.  The image data are already
formatted for each nozzle of the BJ cartridge, and are stored as is in the print buffer.
4) Printing
When control codes with a CR/LF, etc, print start function are processed, and the print
buffer becomes full, the image data stored in the printer buffer are sent to the  BJ cartridge
and printed out.
Chapter 2: Technical Reference
Character "BJ"
Image "
"B" = [ 42 ] Hex.
"J" = [ 4A ] Hex.
ESC * <m> <n> <d> (Select Image Graphics Mode)
       = [ 1B ] Hex., [ 2A ] Hex.,  <m>, <n>, <d>
Character Code:
Character Code:
Control Code:
Image Data:
Input Buffer
[ 42 ]  [ 4A ]  [ 1B ]  [ 2A ]  <m>  <n>  <d>  [ 
 image data ]
Character Code
Control Code
Image data
Font Image
Data (ROM)
Print Buffer
Selected Font
Image Data
Image Data
BJ Cartridge
Select Image
Graphics Mode
Figure 2-2 Data Flow (image)