Specifications

6.2 ID SENSOR FUNCTION IN DETECT SUPPLY MODE
The image density sensor checks the density of the sensor pattern image
once every 10 copy cycles. The CPU receives two voltage values directly
from the sensor: the value for the bare drum (Vsg) and the value for the
sensor pattern (Vsp). These two values are then compared to determine
whether more toner should be added.
1. Vsp ≤1/8 Vsg .....No toner is added. (High density)
2. Vsp >1/8 Vsg .....Toner is added.(Low density)
When the image density is too low, the CPU activates the toner supply clutch
solenoid to add toner over the next 10 copy cycles. The amount of toner
added depends on the value of Vsp, the selected toner supply ratio (SP
mode #31) and the paper size in use. (See page 2-42 for more information.)
When the data of SP mode #35 is set to "1" (factory setting = "0"), the CPU
changes the interval of the ID check from every 10 copies to every 5 copies
for the black development unit.
I/D Sensor
Main Board
ID Sensor LED
CN110-1
CN110-3
CN110-2
ID Sensor Output
TP 110
(PSE)
IC 105
I/O
IC190
RAM
IC111
ROM
+5V
A
K
C
E
B
C
A
VR102
R
SOL 1
+24V
CPU
CN118-2
CN118-1
Toner Supply
CL Solenoid
[BLACK]
Vsg 4V
Vsp
Low Density
High Density
(1/8 Vsg)
1 December 1990
2-36