User manual

95.08.23.11.29
Color LaserWriter 12/600 PS Basics & Theory 1–46
Toner-Level
Detection
When it presses against the photosensitive drum, the cartridge shifts
just enough so that the light from PS11 aligns with a window in the
bottom of the cartridge. In a totally empty cartridge, the light beam
would shoot through this window, out a second window in the top of
the cartridge, and strike the receiving diode of PS11.
In a normal cartridge, the controller judges level of toner by measuring
the duration that light strikes the receiving diode after the stirring plate
has swept in front of the bottom window. If the duration is longer than
a prescribed value, the DC controller determines that the toner is low
and notifies the I/O controller.
Example: See the cyan cartridge in frame 116 of the animation. This
is the position that a cartridge is in when toner level is detected. This
position is called the “press” position. It is the only position in which
the inner workings of the toner cartridge are mechanically driven. The
cartridge is in the “stop” position in frame 115.
Window
Stirring
Plate
Toner
Window
Normal Toner-Low
Toner Sensor PS11 (Emitter)
Toner Sensor PS11 (Receiver)
Animation