HP 8550 Service Manual - Page 224

Enlargement/reduction and image processing 1 Enlargement/reduction a Horizontal reproduction ratio (main scanning direction) Data units may be skipped when they are written into the memory (reduction) or read multiple times from the memory (enlargement). b Vertical reproduction ratio (sub-scanning direction) The scanner is moved at different speeds, thereby changing the width of scanning a single pixel on an original. Table 63. Enlargement/reduction and image processing Reproduction in scanning direction Reproduction in sub-scanning direction Direct All data units are written into or read from the memory as they are. Reduce To reduce by half, every other data unit is written into the memory. The scanner is moved faster to increase the width of scanning a single pixel on an original. Enlarge To enlarge by 200%, all data units are written into the memory as they are, but each data unit is read twice. The scanner is moved slower to decrease the width of scanning a single pixel on an original. 222 Chapter 5 - Theory of operation EN