• They are noisy
  • They create noise when the pins or typeface strike the ribbon to the paper.
  • The use of Sound dampening enclosures or covers become necessary in quiet environments.
• They have limited scope
  • They can only print lower-resolution graphics.
  • Their colour performance is low.
  • They print low quality printouts.
  • Their speeds are limited by waiting for the next input.
• Difficult to adjust single sheet
  • It becomes difficult to wind and align single-sheet papers.
  • Doing it manually is time consuming.
  • The other alternative is the use of unreliable sheet feeder.
  • The paper jams when printing labels on release paper.
  • It occurs when a print wire snags the leading edge of the label while printing at its very edge.
• Paper jams

Read more: http://wiki.answers.com/Q/Disadvantages_of_impact_printers#ixzz1X1jrIiBK