Oki C810 Maintenance Manual page 29

Oki Data CONFIDENTIAL
Error checking methods and remedies
The density correction test function among the other self-diagnostic functions is employed to
check errors. (Section 5.3.2.7)
Remedial methods against different errors
• CALIBRATION ERR, DENS SENSOR ERR
Check 1: If the above indication appears, check the connected state of the sensor
cable.
If the connected state is found abnormal, restore it to the normal state.
Check 2: Check to see whether the sensor surface is stained with toner, paper dust
or any other foreign matter.
If it is found stained, wipe it clean.
If no problem was found by the checks 1 and 2, there is a problem with the circuit.
Replace each of the DENS SENSOR, the relay board (P6y PCB), the PU board (PU
PCB) and the cable one by one and check that no error will occur again.
• DENS SHUTTER ERR
Check 3: Check to see whether the sensor shutter opens and closes normally, by
the MOTOR & CLUTCH TEST of the self-diagnostic function. If the shutter
operates imperfectly, replace the shutter unit.
• DENS ID ERR
Check 4: Take out the ID units and examine them to see if the drum surface has
any abnormal toner smudge.
Replace the LED head (out-of-focus), or replace any ID units with any
abnormality.
To test-operate a new ID unit, use the Fuse Keep Mode of the maintenance
menu.
44015503TH Rev. 1
Principle of toner sensor detection
Toner LOW is detected by the toner sensor (Reflection sensor) installed inside the printer. The
shielding plate is mounted inside the ID and rotates in synchronization with toner agitation.
Moreover, the ID has a shutter fitted. The shutter is synchronized with the operation lever of
the toner cartridge, and the toner sensor can detect that the toner cartridge has been loaded
properly. Detection may not take place normally, and a toner sensor error may be issued, if
the shield plate or toner sensor is stained with toner, or if the ID unit and toner sensor do not
remain exactly opposite to each other in their positions.
Shutter
Toner sensor
Principle of the toner counter
After image data is developed to binary data that the printer can print, the LSI counts the
data as a number of print dots. The amount of toner consumed is calculated from that count
value, and the remaining amount of toner is thus indicated. As opposed to this, the toner
LOW detection by the toner sensor is implemented when the toner amount remaining inside
the ID unit physically decreases to below a certain level.
Principles of ID, belt, and fuser counters
ID counter: One count represents the value that results from dividing the amount of rotation
of the drum by three when three A4-size sheets are printed continuously.
Belt counter: One count represents the value that results from dividing the amount of rotation
of the belt by three when three A4-size sheets are printed continuously.
Fuser counter: One count is registered when paper is shorter than the length of Legal 13-inch
paper. When paper is longer than that, the count number is determined by the
number of times the Legal 13-inch paper length is exceeded. (Rounding up of
decimal fractions)
2. DESCRIPTION OF OPERATION
Shielding plate
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