Grayscale Processing Mode - Ricoh A230 Service Manual

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IMAGE PROCESSING

Grayscale processing mode

A231D534.WMF

The image data from the IPU first goes to the FIFO block. This block consists of 14

FIFO memories (7 for data input, 7 for data output). FIFOs are used because the

image compression is done using four scan lines at the same time to improve the

image compression speed.

The image data then goes to the GA2 IC, where the image data for a whole page is

divided into many blocks (the block size is 4 x 4 pixels) as shown above left. Then,

each block is compressed and sent to HDD, DRAM and SIMM memory. For

printing, the compressed data blocks from the HDD, DRAM and SIMM memory go

back to the GA2 IC. This IC assigns these blocks to the proper positions for

printing, then the data blocks are decompressed. In the image rotation mode, each

compressed data block is rotated into the correct orientation and mapped into the

proper position, then the blocks are decompressed.

A230/A231/A232