Pitney Bowes DM550 - Manual (Page 163)

SV61436 Rev. B 10-3
DM500™ and DM550™ Digital Mailing System Operating Guide
Envelope Sealing Problems
Description Possible Causes Solution
Envelope(s) not sealing
or not sealing properly
Envelope flap dimensions are not
within the acceptable range.
Use envelopes with flap depths between 1"
and 3" (25.4 mm and 76.2 mm).
Flap Depth