Canon BJC 6000 - Color Inkjet Printer Service Manual

2.2 Print Control2.2.1 Print modeThe printer adjusts the carriage action and paper feed action according to theinstalled cartridges, selected print media, printing quality, print data, etc. to ensurehigh quality printing free from diffusion and density variations. Multiple passes areused to provide staggered print timing with multiple nozzles used to print one luster,so that the quantities of discharge that vary from nozzle to nozzle will be smoothedout to minimize density variations. It is smear-free because it is not until the ink forthe last pass printed is fused on the paper that the next pass is printed. Printing canbe divided up to a maximum 8 passes, depending on the print media.2.2.2 Multi-drop printThe BJ cartridges used in this printer incorporate drop-modulation technology,allowing two ink drop sizes, large and small, to be ejected. This allows small dots tobe selectively used for printing in low-density areas to lessen granularity, while largedots can be used in high-density areas to offer high speed printing. In the 720 dpiand 1440 dpi print modes, only small dots are used continuously to provide highlydetailed printing.2.2.3 Photo-printThe photo-print uses both the Photo BJ cartridge, which uses low density ink, and theColor BJ cartridge to provide printing with up to 6 colors of ink. By printing in low-density image areas with ink of 1/3 normal ink density (photo-cyan and photomagenta), printing with rich gradation and suppressed graininess is possible.In the photo-print mode, each pixel is converted into a maximum of 4 values(expressed by two bits), so that for each 360 dpi pixel, up to 4 gradations of each colorcan be printed in a combination of large and small dots. The 6 ink colors of the PhotoBJ cartridge and Color BJ cartridge allow a more dynamic range of printing colors,thus providing higher printing density using less ink than would have been possiblewith 4 low-density ink colors.2.2.4 Automatic switching control of printing nozzlesWhen the printer is set to the normal (for speed) plain paper mode (1 path) with theBlack BJ cartridge (160-nozzle) installed, the number of nozzles to be used forprinting will be automatically set within the nozzle range 48 - 160 during printingaccording to the image data to be printed. Continuous printing with black will beperformed with 160 nozzles, but, in areas with color data, 48 nozzles will be used forprinting to prevent running.4-13BJC-6000Part 4: Technical Reference