Oki MC760 Maintenance Manual page 36

Oki Data CONFIDENTIAL
Error-confirming method and Error-solving method
Use the density correction test function in self-diagnostic mode to confirm the error.
(See 5.3.1.7)
Error solving method
• CALIBRATION ERR, DENS SENSOR ERR
Check 1: When the above display appears, please check the connection of sensor
cable.
When the connection is abnormal, please set it properly.
Check 2: Please check if the surface of the sensor is dirty with the toner and paper
melts etc.
Please wipe the dirt off if the sensor is dirty.
If there are no problems in check 1, 2, and 3, please check the circuit.
Please exchange the density sensor, relay PCB, PU PCB, and the cable one by one,
and then check if the error is displayed.
• DENS SHUTTER ERR
Check 3: Please confirm if the open and close operation of sensor shutter is
normal by utilization of MOTOR&CLUTCH TEST in self-diagnostic mode.
Exchange the shutter unit when the open and close operation is in
trouble.
• DENS ID ERR
Check 4: Remove the ID unit, and confirm if the toner abnormally leaves on the
surface of the drum.
Exchange LED head (Focus control). Or exchange the ID unit.
When a new ID unit is tried to use, please set the fuse keep mode of the
maintenance menu.
45376001TH Rev.1
Toner sensor detection principle
Toner low is detected by the toner sensor (reflect sensor) installed in the equipment.
The light board is installed in ID, and its rotation is synchronized with the mixing of toner.
Moreover, the shutter is installed in ID. Toner cartridge set properly by the lever of toner
cartridge and synchronized toner sensor can be detected.
The following problems may lead to abnormal detection and the toner sensor error is
occurred.
Shutter
Toner sensor
Toner count principle
After the image data is transformed into binary data which can be printed by the printer, the
data is counted as print dot number by LSI. The amount of the used toner is calculated from this
count value, and the residual amount is displayed on the menu.
Toner LOW detection (residual amount display on LCD) by the toner sensor is to detect a
certain amount of the reduction of the toner left in ID.
The principle of ID counter, belt counter, fuse counter
ID counter : when 3 pieces of A4 paper are continuously printed, one third of the
rotation of the drum is set as one count.
Belt counter : when 3 pieces of A4 paper are continuously printed, one thirdof the
rotation of the drum is assumed as one count.
Fuse counter : The length of paper of legal 13 inch is set as nominal value.
If the length of paper is less than this nominal value, it is assumed as
one count. If the length of paper is more than this nominal value,the
counted number is determined by the times of legal 13 inch.
(The number after decimal point is rounded up.)
2. Operating instructions
Light board
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