Toner Level Detection Control - Minolta Di551 Service Manual

TONER SUPPLY UNIT
*2 Toner cartridge
When the toner cartridge rotates, toner is fed to
the outlet of the cartridge through the spiral
groove on the surface of the toner cartridge.
When the outlet of the cartridge faces downward,
toner flows out of the outlet into the agitation/con-
veyance section of the toner supply unit.
90°
rotation
To agitation/conveyance block of
toner supply unit

[3] Toner Level Detection Control

Outlet
Toner level detection is controlled by the TLD
(toner level detection sensor) and the PRCB
(printer control board).
1. Operation
a. Toner level detection
A piezoelectric device is used as the TLD (toner
level detection sensor).
When the level of toner in the hopper becomes
low, the toner supply signal is output to PRCB
(printer control board). As a result, a message is
displayed on the LCD connected to OB1 (oper-
ation board/1).
b. Detection timing
The detection timing is as follows:
• Power-on
• When the front door opens or closes
• During copying
c. Toner supply to toner supply unit
When the no toner state is detected by TLD
(toner level detection sensor), M13 (toner bottle)
is turned ON to supply toner from the toner car-
tridge to the toner supply unit.
d. Detection of no toner state in toner cartridge
If the no toner state is detected by TLD (toner
level detection) after M13 has been held ON for
a specified period of time, the toner cartridge is
assumed to be empty.
2-H-2
S.GND
TONER SIG
T SENSE CONT
5V
P.GND
TONERM CONT
TONERM CLK
TONERM CW/CCW
TONERM EM
PRCB
MS1 MS2
24V2
P.GND
DCPS
TLD
M13