Canon BJC 6000 - Color Inkjet Printer Service Manual

1.3 Flow of Print SignalsThe following outlines the flow of signals as the printer receives data from the hostcomputer and prints it.a) The data from the host computer that contains control commands will be fed into theprinter controller via the parallel interface, which is controlled by the printercontroller, on the control board. The printer controller sends this data on thededicated bus to store it in the receive buffer in the DRAM.b) The data saved in the receive buffer will be sent to the MPU, where it is separatedinto control commands and print data according to the data stored in the controlROM. The control commands will be processed in the MPU.c) The print data will be extracted into the DRAM's print buffer.d) The printer controller, on receiving the Print Start Request, allows the DMA totransfer the print data from the print buffer into the printer controller.e) The printer controller then converts the print data into serial data and sends it asprint signal to the BJ head. The serial print signal will be converted into one columnof parallel print data inside the BJ head. The data, as the print control signal, will beoutput under the control of the printer controller.f) The MPU, while controlling the printer controller, control ROM, and motor driver, andmonitoring the status of the BJ head and printer, controls the entire printingoperation.4-3BJC-6000Part 4: Technical ReferenceControl BoardDRAMabacdePrinter ControllercReceive BufferPrint BufferBJ HeadHostComputerb ff b Control ROMMotor DriverfSensorsfdMPU: Print Signals: Control SignalsFigure 4-3 Flow of Print Signals