User Guide

COPYRIGHT © 1999 CANON INC. CANON 660/2100 REV.0 FEB. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
E. Detecting the Level of Color Toner
The level of color toner is detected by the color toner level sensor (PS621), which con-
sists of a light-emitting section and a light-receiving section.
The light from the light-emitting section found on the outside of the toner cartridges
moves through the light guide to reach the detecting window inside the cartridge.
The stirring plate inside the cartridge moves away toner from around the detecting
window so that the light moves through the cartridge and reaches the light-reflecting sec-
tion of the sensor through the light guide. Then, as toner once again starts to cover the
detecting window, the DC controller PCB finds out the time that passes before the light
is blocked.
When the period during which light moves through the cartridge is longer than a spe-
cific value, the DC controller PCB identifies the condition as absence of color toner, and
communicates the fact to the printer board*
1
.
The machine checks the level of toner in reference to the timing at which the stirring
plate is rotating when power is turned on or when making prints.
*
1
Reader controller PCB (when making prints with the reader unit installed).
Figure 4-304
CHAPTER 4 IMAGE FORMATION SYSTEM
4-16
DC controller PCB
Light-
emitting
section
Color toner
level sensor
(PS621)
CTNSNS
CTNLED
Light-
receiving
section
Color toner
cartridge
Light guide
Download free service manual at http://printer1.blogspot.com