Canon GP160, Service Manual

Page: 107 / 797

COPYRIGHT © 1999 CANON INC. CANON GP160 REV.0 FEB. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 6 IMAGE FORMATION SYSTEM
6-9
VII. CARTRIDGE DETECTION
A. Operation
The circuit for detecting whether or not there is a cartridge, and the volume of toner
in the cartridge, is shown in the diagram below.
The DC controller PCB’s CPU (IC301) compares the developing bias AC (TNRCHKD)
which has been sent from the developing bias generation circuit and the output signal
(TNRCHKT) which has been output from the antenna inside the cartridge, and, judges
whether there is a toner cartridge, and also the level of toner in the cartridge.
When the developing bias is applied to the developing cylinder, the CPU checks the
difference between the 2 signals and judges whether there is a toner cartridge, and also
the level of toner in the cartridge.
Furthermore, the volume of remaining toner is regularly monitored when the devel-
oping bias is being applied, but the presence of the cartridge is only monitored when
developing bias is being applied during the initial rotation.
Figure 6-701
CPU
(IC301)
Developing
bias gene-
ration circuit
Antenna
output detection
circuit
Toner cartridge
[2] TNRCHKT
[1] TNRCHKD
DC controller PCB
[1] TNRCHKT: Developing bias AC output [2] TNRCHK: Antenna output signal