Impact Printer Maintenance

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• impact printer strikes an inked ribbon against paper to leave marks
  • common type is the dot matrix printer
    • uses a column of pins in a print head to strike the ribbon
    • Desktop dot matrix devices are no longer very widely deployed for document printing
      • still used for specialist functions
        • E.g., printing invoices or pay slips on continuous, tractor-fed paper

Impact Printer Paper

• can be used with either plain, carbon, or tractor-fed paper:
  • Plain paper
    • held firmly against the moving roller (the platen) and pulled through the mechanism by friction as the platen rotates
    • cut sheet feeder may be added to some printers to automate the process of providing the next page
  • Carbon paper (or impact paper)
    • used to make multiple copies of a document in the same pass
      • hence carbon copy, or “cc”
    • sheet of carbon paper is inserted between each sheet of plain paper
    • when the print head strikes, the same mark is made on each sheet
  • Tractor-fed paper
    • fitted with removable, perforated side strips
    • holes in these strips are secured over studded rollers at each end of the platen
    • more suitable for multi-part stationery
      • there is less chance of skewing or slippage since the end rollers fix the movement of the paper
    • When you are loading a tractor-fed impact printer with paper
      • ensure that the holes in the paper are engaged in the sprockets and that the paper can enter the printer cleanly
      • Ensure that the lever is in the correct position for friction feed or tractor feed as appropriate for the media being used

Impact Printer Components

• impact printer will also have some form of replaceable ribbon
  • Older-style printers used to have a two-spool ribbon
  • most units now have a cartridge device that slots over or around the carriage of the print head
  • integrated ribbons simplify the design of the printer
    • can be made as a complete loop moving in one direction only
  • two-spool design requires a sensor and reversing mechanism to change the direction of the ribbon when it reaches the end
  • When the ribbon on an impact printer fails to produce sufficiently good print quality
    • the ribbon-holder and contents are normally replaced as an integrated component
  • Some printers can use a re-usable cartridge
  • Follow the manufacturer’s instructions to replace the print head
    • print head may become very hot during use