This is what Epson has to say: -

Key Features

• Fast print speed USD speed of 550 characters per second at 10 characters per inch
  
• Increased reliability Mean time between failure of 25,000 power-on hours
• Flexible printing 24-pin, 80-column dot matrix printer
• Increased number of copies Now original plus six copies
• Same consumables Uses the same ribbons as existing models

Fast print speed

The LQ-590II offers an improved USD (ultra speed draft) speed of 550 characters per second at 10 characters per inch, making a real difference to high-volume print runs such as stock reports and large batches of invoices or freight documents.

Increased reliability

Epson's dot matrix technology is already mature and very reliable. Building on this, the new printer improves the mean time between failure by 25% to 25,000 power-on hours, ideal for challenging conditions or where regular maintenance is not practical.

Same consumables

This printer uses the same ribbons as existing models, so you can upgrade your hardware and continue to use your current ribbon supplies.