Epson TM-U590 Operator's Manual page 48

.
OK to use
Paper feed direction
Since the BOF sensor uses a photo sensor, do not use paper that
has holes at the sensor position or is translucent.
Since the TOF sensor uses a reflective photo sensor and it
detects from the back of slip paper, do not use paper that has
holes or dark portions with low reflection (less than 40%
reflection) at the sensor position.
Form stopper position
18.9
38.5
18
Slip feeding roller
position
Paper feed direction
Use carefully
Do not use
31
TOF sensor
position
Center of the print head
Slip side guide
BOF sensor
3.6
OK to use
Glued area
37.2
21.9
[ All the numeric values are typical. ]
Reference Information 4-7