
Hardware Description
MFC 2000 Multifunctional Peripheral Controller 2000
100723A
Conexant
9-3
9.1.2 Vertical Conversion
Expansion in the vertical direction is accomplished by the processor duplicating lines as needed to achieve the
desired expansion ratio. Reduction in the vertical direction is accomplished by the processor either deleting lines
or ORing lines together as needed to achieve the vertical reduction ratio. ORing of lines is also done by the
resolution conversion logic. When ORing is enabled, each byte of the current line's line buffer data is ORed with
the corresponding byte from the previous line. The DMA channel associated with the Resolution Conversion
Block performs a read-modify (OR) -write operation. The DMA read and write accesses do not occur on
consecutive bus cycles. The firmware should set the DMA channel start address for the line to be ORed equal to
the address for the previous line. The threshold of the ORing function is selectable. If the threshold value is 0, all
the black pixels in the current line will be used for the ORing function. In order to reduce the background image
noise, the threshold value can be set from 1 to 7. If the threshold value is set to 2, the single black pixels and 2
contiguous black pixels in the current line will not be used for the ORing function.
9.1.3 Shingling
Shingling is a process in which color intensity was built up in the course of several passes of the head for the
inkjet printing. The objective is to print a portion of the data on each of the passes, using a checkerboard mask to
decide which pixels to print on each pass and which pixels to mask out. This allows time for dots of ink printed on
one pass to dry somewhat before adjacent ink dots are printed on subsequent passes, thereby improving quality.
The checkerboard varies with the level of shingling in use. This level is described as a percentage, with 50, 33,
and 25 percent shingling levels having been discussed to date. Briefly:
50 percent shingling requires two passes of the head. The matrix below shows a section of the pixels on the
page, with the number being the pass of the head on which the pixel in printed:
1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2
2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1
1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2
2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1
33 percent shingling requires three passes to build up full intensity:
1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2
2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1
1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
25 percent shingling requires four passes:
1 3 2 4 1 3 2 4 1 3 2 4 1 3 2 4 1 3 2 4 1 3 2 4
2 4 1 3 2 4 1 3 2 4 1 3 2 4 1 3 2 4 1 3 2 4 1 3
1 3 2 4 1 3 2 4 1 3 2 4 1 3 2 4 1 3 2 4 1 3 2 4
2 4 1 3 2 4 1 3 2 4 1 3 2 4 1 3 2 4 1 3 2 4 1 3
Paper moves a portion of the height of the nozzle array between passes of the head, so different nozzles print
different dots on a scanline. In this situation, the data for the scanline must be moved from the band buffers to the
print buffers several times, with a mask applied along the way so that only part of the data gets through on each
move. Note that printing is slower when shingling is in use, so bandwidth is not significantly affected. Also note
that the mask changes between scanlines.