Automatic Adjustment Of Gamma Correction - Toshiba FC-22 Manual

1. 7 Automatic Adjustment of Gamma Correction

(1) At the time of unpacking:
When the reproduction of gradation is not appropriate, the gradation reproducibility of all colors Y,
M, C and K can be corrected by performing this automatic adjustment of gamma correction. Check
the image, and if the gradation reproduction is not satisfactory, make this adjustment as described
below.
(2) When any of the following parts has been replaced, be sure to make this adjustment:
• Laser optical unit
(3) When any of the following parts are replaced or adjusted, make a copy and check the image to
determine if the adjustment is necessary:
• Main charger
Note: Be sure that this adjustment be made after performing the copy image adjustment in "1.5 Auto-
matic Initialization of Image Quality Control" and "1.6 Copy Image Dimensional Adjustment".
Code Adjustment item
643 Automatic adjustment
of gamma correction
FC-22 ADJUSTMENT
• Drum
• Transfer belt
<Procedure>
Adjustment of Text or Map mode
(1) While pressing [0] and [5] simultaneously, turn the power ON.
Adjustment mode
(2) Press [4] [SETTINGS] and output a "Patch chart for gamma
adjustment".
(3) Place the "Patch chart for gamma adjustment" produced in step
(2), face down onto the original glass, with the side, on which a
black band is present, precisely against the original scale.
(4) Input code [643] with digital keys and press [START].
(5) Input [2] with digital keys, and press [START] and then [INTER-
RUPT] The scanner reads the original automatically and
performs automatic gamma adjustment calculation (approx. 30
sec.).
(6) When the adjustment ends normally, "SCAN COMPLETE" is
shown. Press [START] to have the adjustment results reflected.
(To cancel the reflection of adjustment results, press [STOP].)
When "COMPLETE" is shown, press [STOP] to return to the
standby state.
In the case of an abnormal ending, "ADJUSTMENT ERROR"
is shown. Press [STOP] to clear the error display. When it is
cleared, the control panel display will return to the standby state.
Then, check if the gradation pattern image on the original glass
is oriented in the wrong direction or if it is placed inclined on the
original glass, and then repeat step (3) and afterward.
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January 2000 © TOSHIBA TEC