Ricoh M040 Service Training page 120

New unit detection is performed when machine is powered on. After replacing the ITB unit
(after H signal is detected), image transfer belt counter is cleared.
Fuse type register is open due to current in the circuit. L signal is detected as new unit
signal, and counter for ITB begins. Thus SP-code "Reset Transfer Unit Life Counter" is not
necessary.
"Near end" is indicated when transfer unit counter reaches 89.2 k. Machine stops after 90 k.
Slide 120
.
New Detection Mechanism
for Image Transfer Belt Unit
Mina body Image transfer belt unit
+24V
C
120
MD-P1b / M040 / C311N
MD-P1c / M041 / C312DN
New unit incorporates fuse
type register. When machine
detects low resistance, it is
interpreted as a new unit.
Once used, the fuse opens,
and if reinstalled, the machine
Fuse type register
recognizes that there is an
older unit being reinstalled.
Condition Old New
New unit signal Ｌ Ｌ Ｌ Ｌ Ｈ Ｈ Ｈ Ｈ
Fuse resistance High Low