Canon BJC-55 Service Manual

1.4 Print DriveThe printer outputs control signals from the ASIC's printer controller to the BJ head toeject ink from the BJ head for printing.The control signals consist of the print control signal for ejecting ink from the head'snozzles and the temperature control signal for adjusting the head's temperature so thatthe amount of ink ejected is uniform.To archive optimum printing, both these control signals are optimized by the printercontroller and sent from the carriage ribbon cable's signal contacts to the BJ head.The drive frequency varies depending on the printing mode and BJ cartridge type.1.4.1 Printing drive controla) Black BJ cartridge drive controlThe black BJ cartridge drive control is executed by dividing the head's 128 nozzlesinto 8 blocks (16 nozzles each). These blocks are further divided into odd and evenblocks (8 nozzles each). The odd blocks eject ink simultaneously and the evenblocks do so as well. The control signals for the former are the block enable 0, 1,and 2 signals (BENB 0, 1, 2) and for the latter the signals are the even/odd enablesignals (Even/Odd ENB). The heat enable A and D (HENB A, D), which are theheater drive control signals for ejecting the ink, comprise of a prepulse and mainpulse. To constantly archive optimum ink ejection, the internal conditions such asthe head's rank, printer temperature, and head temperature are monitored and theheater drive pulse width is varied before the pulse is output. Furthermore, the printdrive signal from the printer controller is transferred to the BJ head's shift resistoraccording to the HLATCH timing. The printing drive signal (HDATA) is latched andwhen the print control and heater drive control signals are output together, theheater for the applicable nozzles is driven and the ink is ejected.b) Color BJ cartridge (Large/Small Drop) drive controlThe two-size droplet type color BJ cartridge has a print head with 136 nozzles andeach nozzle has two heaters, one infront of the other, that regulate the ejection oflarge and small ink droplets. The 136 nozzles are divided into 8 functional blocks,each block consisting of 16 nozzles. Ink is ejected consecutively from each block.The order and selection of nozzles to be used are controlled by BLOCK ENABLEsignals (BENB 0,1,2) and the EVEN/ODD ENABLE signal (Even/Odd ENB). HEATENABLE signals (HENB A,B,C,D) control the heater boards.4-5BJC-50Part 4: Technical ReferenceBBBBBBBBBBBBBBBBAAAAAAAAAAAAAAAABBBBBBBBBBBBBBBBAAAAAAAAAAAAAAAA1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64EOBE8EOEOEOEOEOEOEOBE7BE6BE5BE4BE3BE2BE1::BE1 to BE 8 : Block Enable 1 to 8E : Even EnableO : Odd EnableA : Heat Enable 0B : Heat Enable 1Figure 4-3 Print Sequence (Black BJ Cartridge in HQ Mode)