Canon iPF710 - imagePROGRAF Color Inkjet Printer, Service Manual

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Chapter 2
2-3
c) The main controller decompresses the print data transmitted to the ASIC and gets it through resolution, color
and 5-color binarization conversion while loading the data into DDR-SDRAM from time to time.
It also converts the print data to 5-color binary equivalents of image and command data.
d) The ASIC (IC1) generates image data synthesized with mask data within the ASIC in sync with the discharge
time while loading the data into DDR-SDRAM from time to time.
e) The ASIC (IC2) collects printhead information from EEPROM mounted on the printheads and the printer
temperature from the latch IC on the carriage board and transmit them to the ASIC (IC1).
The ASIC (IC1) also receives mask pattern data from the firmware installed in flash ROM.
f) The ASIC (IC1) converts the image data synthesized with the mask pattern to data associated with the
printhead information and the printer temperature, transmitting the data to the printheads as a print signal. It
transmits heat pulses to the printheads at the same time to optimize head driving.
g) The printheads convert the received print signal from a serial signal to a parallel signal for each row of nozzles
and ANDs it with the heat pulses for perform printing.
h) The ASIC (IC1) controls the general aspects of image processing and print drive control by detecting the
status of the individual printer components with reference to the adjustment values stored in EEPROM. SDR-
SDRAM is used as work memory.
i) The ASIC (IC2) controls the general aspects of drive control by controlling button actuations and message
displays on the basis of the firmware installed in flash ROM.
2.1.3 Print Driving
0013-5398
Print and control signals are transferred via the carriage relay PCB and head relay PCB to the printheads to
discharge inks from the nozzle assembly at printing.
Each printhead has 12 trains of nozzles arranged in a zigzag pattern.
This printer uses one printhead.
(In installed state, from left to right, C, M, Y, MBK, MBK, BK)
Print signals directed at each nozzle train are even-numbered nozzle data (Hx-x-DATA-x-EV) and odd-
numbered nozzle data (Hx-x-DATA-x-OD). These are transferred in timing with a data transfer clock (Hx-
CLK) and data latch pulses (Hx-LT).
The Heat Enable (Hx-x-HE-x) drive control signal enables inks to be discharged from the nozzles.
1. Pint drive control
Each train of nozzles in a printhead has 2,560 nozzles.
Ink discharge nozzles are selected split in 40-, 20- or 10-nozzle blocks according to the Block Enable
information in the even-numbered nozzle data and odd-numbered nozzle data.
Each selected block of nozzles is impressed with a Heat Enable signal generated with variable pulse widths
according to the head rank, head temperature and printer temperature for optimized ink discharges. The nozzles
are driven by heater boards in the nozzles to discharge inks. Optimal nozzle blocks are selected according to
the print path.
The diagram below illustrates the relationship between a 40-block nozzle and nozzles driven.