Cause: Side Fence, Rear Fence Set Incorrectly

Paper with excessive buckle [A] can cause double-feeding, so adjust the fences to the correct positions so the paper lies flat [B].

Cause: Paper Curling

[A]

Concave curl. Paper exits with curve down.

[B]

Convex curl. Paper exits with curve up.

In either case if the curl is excessive (not within specification), this can cause double-feeding.

Solution: Measure and correct curl.

Measuring amount of curl

  1. Take a sheet of paper causing the problem and lay it on a flat surface.
  2. Set a scale at each corner of the paper and measure the amount of curl at each of the four corners. SEF curl is shown at [A], and LEF curl is shown at [B].

  • Place the paper face down to measure back curl accurately.

Allowed Amount of Curl

40.0 g/m2 to 300 g/m2   

Concave curl: 5mm

Convex curl: 5mm

300.1 to 350.0 g/m2      

Concave curl: +8mm

Convex curl: -8mm

Correcting Curl

  1. Lay the stack on a flat surface, opposite to the direction of curl.
  2. Bend the edge up as shown to straighten it the edge.
  3. Repeat the procedure for the other end of the stack.
  4. Fan the paper before loading it to loosen the sheets. Paper sticks together if it has excessive static electricity, burrs (due to edge cutting) or is damp.
  5. Hold the paper by the ends and slowly bend it several times.
  6. Make sure plenty of air gets in between the sheets.

If the above method is difficult, fan the paper in the following way.

  • Hold the paper by the edge and fan it by flipping through the sheets. Repeat this fanning for all four sides.
  • Place the paper on a flat surface and press down the edges.
  • Fan it by flipping through the sheets. Repeat this fanning for all four sides.