Jamming issues on the DM400C, DM450C and DM475

Ensure that your mailing material meets specifications and check your meter to remove dust and debris to resolve jamming issues.
Products affected: DM400C™, DM450C™, DM475™


Mailpieces enter the meter and get stuck or stopped before exiting.


There are several possible reasons for jamming issues:
  • The sealing lever may be in the wrong position.
  • The mailpiece may not be in specification for this meter.
  • A sensor may be dirty or covered.
  • A part may be worn or faulty.


Solution 1: Ensure that your material meets specifications

Review the material specifications including the minimum and maximum envelope sizes, envelope stack height, and tape size details.

Envelope Size

  • Minimum: 3.5 x 5 inches
  • Maximum: 13 x 15 inches
  • Maximum: 13 x 14 inches (in WOW mode on DM475)

Envelope Flap Depth

  • 3 inches

Envelope Thickness

  • Minimum: .02 inches
  • Maximum (DM300c): 3/8 inch
  • Maximum (DM400c/DM475): 5/16 inch

Stack Height for Mail

  • 3 inches – This is the height of the inner edge of the side guide

Envelope Weight

  • Minimum: .035 oz
  • Maximum: 16 oz

Tape Size

  • Minimum: 1.75 x 4 inches
  • Maximum: 1.76 x 8 inches

Material dimensions

For a proper seal, the envelope’s minimum flap angle must meet the following criteria:

  • For envelopes with a flap length from 1 to 2.36 inches, the minimum flap angle is 18 degrees.
  • For envelopes with a flap length greater than 2.36 inches to the maximum flap length for the particular model, the minimum flap angle is 21 degrees.

Material specifications - mail flap angle

If your issue is not resolved, try Solution 2.

Solution 2: Check your meter to resolve jamming issues

  1. Lift the feeder cover.
  2. Open the blue jam release (there are 2 blue jam releases on the DM475).
    pull the blue lever
  3. Remove any mailpieces in the feeder.
  4. Turn the jam release knob under the display clockwise.
    move clearance lever clockwise
  5. Remove any mailpieces in the printer.
  6. Check that the seal lever is in the correct position.
  7. Use a can of non-flammable canned air to blow onto the feed deck that the envelopes travel on, ensuring that all dust and debris are removed, working from the left side of the machine toward the exit.
  8. Close the jam release knob and blue jam release lever.
  9. Close the feeder cover.
  10. Clear the error and retry your mailpiece if it is not too damaged.

For more information, including diagrams of the release levers, see the Feeding Problems section in the DM300C, DM400c and DM475 Operator Guide.

If you need further assistance, please contact us.

UPDATED: January 03, 2023