Ink Sensor (Same As For Bj F600); Cover Sensor; Pump Sensor - Canon S6300 Service Manual

Part 3: Technical Reference

1.4.3 Ink sensor (Same as for BJ F600)

Consisting of an LED and photo sensor, the ink sensor uses optical means to detect
whether there is ink in the ink tank.
At the bottom of the ink tank is an indentation that works like a prism.
When there is ink in the ink tank, the refractive index of the ink and the prism's resin
material is about the same. Therefore, the reflected amount of light is small.
When the ink is exhausted, the refractive index of the air and the prism's resin is very
different, so all the light entering the sensor is reflected and the amount of reflected
light is high.
The ink sensor detects the difference in the reflected light amount to determine
whether or not there is ink in the tank. The MPU detects the voltage that changes
according to the change in the reflected light amount. The analog value that is input
is converted to a digital value by an internal A/D converter.
When the printer detects no ink in the ink tank, it indicates "ink low" on the status
monitor for the respective ink tank. After the printer detects no ink in the ink tank, it
starts to count the number of ejected dots corresponding to the amount of ink (about
20% of the ink amount) in the sponge and it starts to detect the no-ink error.
This error is detected in the following cases: While the power is ON, when the front
cover is closed, after the pumping operation, or after the set number of dots have been
printed. If the front cover is opened during the ink amount measurement, the external
light may prevent an accurate measurement. The presence of an ink tank will also not
be detected. If there is no ink tank, there will be no reflected light and the printer will
therefore assume that there is ink.
Refracted
Light
Incident
Light
Photo
Transistor
Ink Sensor
Ink Present

1.4.4 Cover sensor

The switch-type cover sensor detects whether the front cover is open or not. When the
printer detects that the cover is open, it will move the carriage to the replacement
position.

1.4.5 Pump sensor

The switch-type pump sensor detects the tube pump rotation's initial position. From
the pump's initial position as detected by the printer, the printer will start to control
the pumping operation.
Ink
Reflected
Light
Incident
Light
Photo Transistor
Ink Sensor
No Ink
Figure 3-6 Ink Sensor
3-8
Ink Tank
Air
Prism
Reflected Light
(Completely Reflected)
S6300