Oki MC770 Maintenance Manual

45584901TH Rev.1
4-5 /
Oki Data CONFIDENTIAL
4.2 Image Quality Adjustment (Copying Function)
4.2.1 Automatic gamma adjustment
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gammaadjustment.Incase
the gradationreproduction of the image checked is not satisfactory, makethis adjustment as
described below at parts replacement.
Whenunpackingoranyofthefollowingpartshasbeenreplaced,besuretomakethis
adjustment:
• Drumunit
• Transferbeltunit
• SRAMboard(CUboard)
• PUboard
• HDD
Notes:
Be sure that this adjustment be made after performing the image adjustment in

P.4-2“4.1.2
Performing density correction” and

P.4-3“4.1.3ImageDimensionalAdjustment”.
<Procedure>
(1) Whilepressing[0]and[5]simultaneously,turnthepowerON.
→
Adjustment Mode
(2) SelecttheA4/LTTray.Keyinthepatternnumberandpressthe[FAX]buttontooutputa“Patch
chart for gamma adjustment”.
<Adjustment Mode (05)>
Pattern No. Pattern No. Remark Paper type
4 Color/black integrated Whenperformingcode05-7869 All paper types
200 Color/black integrated Whenperformingcode05-7871-0 Plain paper
204 Color/black integrated Whenperformingcode05-7871-2 Thick paper 5
206 Color/black integrated Whenperformingcode05-7871-3 Thick paper 1
208 Color/black integrated Whenperformingcode05-7871-4 Thick paper 2
210 Color/black integrated Whenperformingcode05-7871-5 Thick paper 3
212 Color/black integrated Whenperformingcode05-7871-6 Thick paper 4
216 Color/black integrated Whenperformingcode05-7871-8 Special paper 4 to 6
218 Color/black integrated Whenperformingcode05-7871-9 User type
220 Color/black integrated Whenperformingcode05-7871-10 Plain (Thin)
(3) Place the patch chart for adjustment printed in step (2) face down on the original glass.
 Placethechartaligningitssidewith2blacksquaresagainsttheoriginalscale.
(4) Keyinacodeandpressthe[START]button.
→
The scanner reads the chart automatically and performs automatic gamma adjustment
calculation (approx.30 sec.).
<Adjustment Mode (05)>
Code Item to be adjusted Contents
7869
(7871)
Automatic gamma
adjustment
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 gamma adjustment. The
result of 7869 is applied to all paper types. The result of 7871 is
applied to the specified paper type.

Oki MC770 Specifications

General

Brand	Oki
Model	MC770
Category	All in One Printer
Language	English