Canon BJC-55 Service Manual

2.2 720 dpi Printing/Smoothing Feature2.2.1 Canon extension modeIn Canon extension mode, the printer driver creates 720 dpi data for the horizontalaxis and sends it to the printer, allowing the printer to archive high-quality printing.With a black BJ cartridge installed, the printer driver smoothes the printedcharacter's edges to 720 dpi along the horizontal axis. The 720 dpi data for thehorizontal axis is sent to the printer and the edges are smoothed at a higherresolution.When a color BJ cartridge is installed, a 360 dpi data is represented by a set of twodots printed simultaneously to obtain a 720 dpi resolution. The multi-value data ofthe pixels processed by the printer driver for color correction, etc., is assigned threevalues (no printing, single-dot printing, two-dot printing) for each pixel. In the case oftwo-dot printing, the second dot is printed in the 720 dpi position. As a result, thismethod enables the printer to archive high degree gradation printing.2.2.2 Emulation modeWhen a black BJ cartridge is installed, the printed character's edges can be smoothedat a high resolution of 720 dpi along the horizontal axis. Dots along the character'sedges are added or deleted to smooth their edges. Along the horizontal axis, dots arealso overlapped by half a dot. This eliminates jaggies and doubles the equivalenthorizontal resolution.This smoothing feature greatly improves low-resolution, 180 dpi characters. However,it does not give noticeable improvement to TrueType fonts and illustrations.Note that with a color BJ cartridge installed, the emulation mode smoothing featurecannot be used.4-15BJC-50Part 4: Technical ReferenceBJ 1/720 inchAdd DotsDelete Dot1/360 inch 1/360 inchFigure 4-12 720 dpi/Smoothing Function