Epson TM-U950 Technical Manual page 52

CONFIDENTIAL
Slip paper insert sensor assembly
The slip paper insert sensor assembly detects the tip of the paper when slip paper is being
inserted and detects the end of the paper during printing. It is mounted immediately to the right
of the paper set position.
The sensor sub-assembly uses an LED and photo transistor arrangement. When slip paper is
inserted, it blocks the light from the LED and causes a change in the output level of the photo
transistor. This change is used to generate the slip paper presence signal.
Figure 2-11. Slip Paper and Slip Paper Insert
Slip paper eject sensor assembly
The slip paper eject assembly is mounted on the right side of the slip paper eject slot. It detects
whether or not the paper has been properly ejected after printing.
The sensor sub-assembly uses an LED and photo transistor arrangement to detect light reflected
by the paper. Since the photo transistor is also subject to external light, the light of the LED is
modulated by turning it on and off with a 2-kHz pulse. The output of the photo transistor is then
extracted via a 2-kHz filter to inhibit the influence of external light.
Paper roll sensor assembly
The paper roll sensor assembly consists of the paper roll sensor, and paper sensor lever. The
assembly detects the presence of the paper roll.
Rev. A
Sensor Sub-assembly
Figure 2-13. Slip Paper Eject Sensor Circuit Diagram
TM-U950/U950P Technical Manual
Figure 2-12. Slip Paper Insert
Sensor Circuit Diagram
Mechanism Configuration and Operating Principles 2-7