Image Processing; Image Density Setting - Ricoh C217 Service Manual

3. IMAGE PROCESSING

3.1 IMAGE DENSITY SETTING

The A/D conversion parameters (refer to page 2-43 of the VT1730 service
manual) and thermal head energy changes depend on the image density
selected on the operation panel.
The table below illustrates the relationships between the image modes,
parameters, and the thermal head energy.
Shading Distortion Memory
Image Line Mode
Setting
Photo
Mode
In the VT1730 model, the thermal head energy is always the same,
regardless of the image density setting. Only the A/D conversion parameters
are changed depending on the selected image density. Using this method,
the image density of solid black areas will not change even if a darker setting
is selected. This is because all of the pixel data will be the same after the
binary processing, if the area is purely black.
In the VT1800, when Darker 2 is selected, the A/D conversion parameters
are the same as those of Darker 1, but the thermal head energy is increased
to 115% of the normal thermal head energy. (This is done by changing the
pulse width.) As a result, the density of solid black areas will become darker.
C225
VH (%) M1 (%) M2 (%) M3 (%) VL (%)
100
Lighter 74.0
Normal 100
Darker 1 100
Darker 2 100
Lighter 70.0
Normal 80.0
Darker 1 85.0
Darker 2 85.0
2-4
86.5 73.0 59.5
57.0 40.0 23.0
76.5 53.0 29.5
79.8 59.5 39.3
79.8 59.5 39.3
36.6 19.6 11.4
43.4 24.8 15.8
47.9 29.0 19.9
47.9 29.0 19.9
T/H
Energy
(%)
46.0
6.0 100
6.0 100
19.0 100
19.0 115
7.0 100
11.0 100
15.0 100
15.0 115
SM