Print Signal Flow; Data Between Host Computer And Printer; Print Signal Flow In The Printer - Canon BJC-5000 Service Manual

BJC-5000

1.3 Print Signal Flow

1.3.1 Data between host computer and printer

Conventionally, control functions were provided by a printer's firmware. For this
printer, however, these control functions are processed by the printer driver on the
computer.
Conventional printers receive the image data in the raster direction (horizontal
direction data) which is created on the printer driver. The printer converts the raster
direction image data it receives into column data (vertical direction data) and then
executes printing.
The printer driver on the host computer handles all processes until column data
creation and their the printer receives this column data and prints it. Thus, high
speed printing is realized because the printer does not need to convert the raster data
into column data before printing.

1.3.2 Print Signal Flow in the Printer

The print signal flow from when the printer receives the print data to when printing is
executed is described below.
a) The printing information (column data matching with the nozzle arrangement of
the built-in printhead) including control signals output by the host computer is
loaded through the parallel interface into the MPU & printer controller on the logic
board. The printing information is separated into control commands and print
data based on the data stored in the control ROM. The control commands are
processed in the MPU & printer controller. The print data is stored in the DRAM
print buffer.
b) The MPU & printer controller outputs the print data to the bubble jet head in the
form of print signals. In the bubble jet head, the print data is converted from serial
signals to parallel print data for each printed line. Printing is performed as the
MPU & printer controller is controlled by the print control signals.
c) The MPU & printer controller monitors the status of the bubble jet head and
printer and uses the control ROM and motor drivers to manage all printing driver
controls.
Computer
BJ Head
a
Host
b
Printer Controller
c
:
Print signal
:
Control signal
Figure 4-3 Print Signal Flow
a
b
MPU &
a
c
c
4-3
Part 4: Technical Reference
DRAM
Print Buffer
Logic Board
Control ROM
Motor Drivers
Sensors