Canon BJC-8500 Service Manual

Also see for BJC-8500: User manual

Contents

1.5 BJ Cartridge DriveThe printer controller drives the BJ cartridges in accordance with print data andcontrol signals that are output from the logic board.The control signals perform three functions. They determine the ink ejection timingand ink amounts ejected from the nozzles of the BJ cartridges, maintain the BJcartridges at the optimum temperature, and stabilize the ink ejection amounts.1.5.1 Printing drive controlPrinting drive control on this printer is executed by dividing the heads nozzles into 16blocks and simultaneously driving these blocks. This is to reduce the number ofsimultaneous ink ejections from adjacent nozzles. This method of drive control isapplied simultaneously to two BJ cartridges (Black BJ cartridge BC-80 + Color BJcartridge BC-81, or Color BJ cartridge BC-81 + Photo BJ cartridge BC-82 Photo).The heat enable signals are the heater drive control signals for ejecting the ink, andare comprised of a pre-pulse and main pulse. To constantly achieve optimum inkejection, internal conditions such as the head's rank, printer temperature, and headtemperature are monitored, and the heater drive pulse width is varied before the pulseis output.4-7BJC-8500Part 4: Technical ReferenceCLKData1Signal NameData2DecoderOUTB.G.HESHEHeater Drive Current(printing heater)Data 1 and 2are latched atthe rising edge.2.0 to 2.8μsecHeater Drive Current(non-printing heater)(BLE)0 32 64 96 1281 3310 42 74 106 138 23465 97 129224225 11 43 75 107 139 2350- -151I/ *(Min.50μsec)I/ */17(Min.2.941μsec)* =drive frequencyData 1 and 2are latched atthe rising edge.Data 1 and 2are latched atthe rising edge.Figure 4-7 Printing Drive Control