APS SS205-V4+ LV - End of Paper Sensor

Advanced Printing Systems
SS205-V4+ LV - Technical Manual - Rev B Page 18
5. END OF PAPER SENSOR
SS205-V4-LV has an end of paper opto sensor achieved by a photo-transistor. Arrange the circuitry
so that no energy is applied to the head when there is no paper. If the head is energized when there is
no paper and the head is in the down position, then both roller and head may be strongly damaged.
The table below contains opto sensor specification.
Parameter
Symbol
Conditions
Min.
TYP.
Max.
Unit
Input
Forward Voltage
VF
IF=10mA
-
-
1.3
V
Reverse Current
IR
VR=5V
-
-
10
μA
Output
Collector Dark Current
ICEO
VCE=10V
-
-
0.2
μA
Transfer
characteristics
Collector Current
IC
VCE=5V
IF=10mA
180-
-
440
μA
Response
time
Rise
time
tr
VCE=2V
IC=100μA
RL=1KΩ,d=1mm
-
30
-
μsec
Fall
time
tf
-
25
-
μsec
One possible interfacing of the opto-sensor circuit is shown in the figure below:
Where:
V1 = 5V
R1 = 380 Ohms (for ILED = 10mA) or R1 = 180 Ohms (for ILED =21mA)
V2 = 3.3V
R2 = 4700 Ohms
VOUT = V2 - R2·ICC
In such configuration Phototransistor Threshold Current can be defined as follow:
Light Current
I Led (mA)
Phototransistor Threshold Current
Icc (µA)
10
15
21
33