Gestetner A294, Service Manual

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IMAGE PROCESSING
A294/A295 2-24 SM
Pale Mode
The image processing for pale mode is basically the same as in text mode.
However, the contrast of the original is low. So, to preserve details, a stronger MTF
filter is used. Also, the independent dot erase level is set at a lower level, so that
only the faintest of dots are deleted; this ensures that dotted lines and periods are
not deleted.
With UP Mode (Copy/Document Server Features – General Features – Original
Mode Level), the user can select ‘Soft’, ‘Normal’, ‘Sharp’, and ‘SP Mode Changed’.
The settings of the SP modes indicated with an asterisk (*) are not used unless the
user selects ‘Service Mode’.
Image Processing Path Related SP Modes
Input
Correction 1
•
SP4903-068 *
(Scanner Gamma Thresh Level)
•
SP4903-73 *
(Background Erase Level)
Input
Correction 2
•
SP4903-063
(Independent Dot Erase Level)
Filtering
•
SP4903-015 *
(Pre Filter)
•
SP4903-055 to 056 *
(MTF Filter Coefficient – Pale
Originals)
Magnification
•
SP2909-001
(Main Scan Magnification)
ID Control
Gradation
•
SP4904-23
(Line Width Correction Type)
Auto Shading
Independent Dot Erase
MTF
Main Scan Magnification
γ
Correction
Background Erase
Grayscale Processing/
Line Width Correction
Rev. 2/2000
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