Minolta CF910 Service Manual page 48

11 Miscellaneous Processing: PWB-C
<Improved reproduction of black characters>
The Bk data for black characters is replaced with MAX (DR, DG, DB) data, which
improves reproduction of black fine lines, realizing reproduction of black characters that
do not depend on line width very much.
Edge Emphasis
• The number of data readings on the edges of the image is increased to make the out-
line of the image sharper as it appears on the copy.
• The amount of edge emphasis is obtained in directions of 0°, 90°, 45°, and -45° and is
determined using the greatest value obtained.
<Edge 3 × 3 crossing>
Edge emphasis produces a difference in contrast between the edge and center of a char-
acter. This processing identifies the center of a character whose density is low over a
width of 1 or 2 dots as a new edge.
Smoothing
The noise components contained in the image data are removed to smooth the data.
Density Adjustment and Color Balance
• Density adjustment is made by changing the angle of the γ curve that represents the
relation between the input and output of the image data.
• Color balance is adjusted by changing the angle of the γ curve for each color.
Gamma (γ) Correction
The type of γ curve is changed to make the image brighter or darker, or sharper or softer.
256
Output
128
0
DR DG DB
256
Higher
Density
Output
128
0
Darker
Brighter
128 256
1144M154AA
Input
To Printer Head (PH)
M-31
curve
Lower
Density
128 256
1144M153AA
Input
256
Sharper
Output
128
0
128
Input
1154M020AA
1144G04MBA
1154M021AA
1144G05MBA
Softer
256
1144M155AA