MFC2000 datasheet(243/426 Pages) ETC

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Hardware Description

MFC 2000 Multifunctional Peripheral Controller 2000

100723A

Conexant

11-11

11.4.2 Swath Loader Requirements (Software Issues)

Due to the fact that the color nozzles are staggered as well as the fact that there is a physical separation VP of

the color groups themselves, there are very special requirements imposed on the swath loader. In a situation

where the mode is black only, then a minimum of two block buffers within image memory are required. This is due

to the fact that while one block buffer is being printed, the other buffer may be simultaneously filled by the image

loader.

Color mode is quite different from black-only print mode. In color mode, three separate colors are used: yellow,

magenta, and cyan. The order of these colors may differ from one printhead to another. This is why the colors

have been assigned simply as “Color1”, “Color2”, and “Color3” in Figure 11-1. On the first print swath of a page,

Color3 is printed. On the next print block, Color3, and NG-VP + 1 nozzles of Color2 are printed. On the third pass,

Color3, Color2, and NG-(2*VP) + 1 nozzles of Color1 are fired. In looking at this pattern, we see that two buffers

are required to deal with printing Color3 (one block history required), three buffers are required in printing Color2

(two block history required), and four buffers are required in printing Color1 (three block history required).

Peerless PCL has a limitation that the color blocks that comprise the image data cannot be easily split up in order

to take into account the VP parameter. The color data must be contiguous within the blocks. Due to this fact

(along with the fact that the CPU may need to perform some preprocessing of the image prior to printing), the

color buffers that are provided for use by the Bit Rotation Block are prepared by the CPU in the background. The

figure shows the typical preparation of these buffers in the background by the CPU.

Note:

Before scanning starts, the two prepared color buffers must be zero-filled by the CPU for

reasons of top-of-page boundary conditions. If, at the end of the printed page, there are fewer

lines than the number in the prepared buffers, then the remainder of the prepared buffers must

be zero-filled to account for bottom-of-page boundary conditions.

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