Print Process Explained

12 Jun

Many of you reading this blog own a large format print device. Have you ever wondered what happens after you click Print? In this week’s post, we try to break down the process.

All of these steps occur during the print cycle:

  1. Erasing – This is done by a series of LEDs to reduce the electric potential on the drum to zero volts while it rotates. It is the removal of negative electric charges.
  2. Drum Cleaning – Residual toner left on the drum is cleaned off by a cleaning roller that has 800 volts applied to it and the toner “jumps” on to the roller.
  3. Charge – The drum is now charged by the corona wire and grid plate  to a -820 V, which corresponds to the white (blank) areas of the printed image.
  4. Exposure – The LED Printhead throws infrared light onto the drum, which corresponds to the black areas of the image. The light causes the drum to lose its charge to -50V where the LED “hits” the surface. An “Electrostatic Latent Image” is now formed on the drum.
  5. Development – The developer assembly consists of 3 rollers: a developer roller, a supply roller, and a regulation roller.  The developer roller carries the toner to the drum which is fed by the supply roller. The regulation roller “meters” the amount of toner that is applied to the developer roller. Voltages are applied to all 3 rollers to help carry the toner.
  6. Pre Transfer LED – The purpose of this LED is to hit the white non-image areas of the drum with more light to bring down the surface potential from -820V to -80V. Otherwise, it would be difficult to get the media off the drum due to the high static charge and thus would cause a  paper jam.
  7. Transfer – The transfer corona wire puts a positive charge on the back side of the paper which now causes the toner to “jump” from the drum onto the paper.
  8. Separation – The separation corona wire puts an AC charge on the paper so the paper won’t stick to the drum along with the help of separation lamps (LEDs). The paper now “falls” off the drum and goes into the fuser.
  9. Fusing – Now that the image is on the paper, it is carried into the fuser where it is “pressed and baked” into the fibers of the paper by two fuser rollers and an extremely high heat of 160º C.

This picture shows the entire process.

This amazing process can be done to 22  “D” size copies per minute on the fastest machine that BPI offers.  The KIP 9900 prints at 600 x 1800 DPI while still being 100 percent toner efficient.  If you would like to see this machine in action, call BPI for a demonstration.


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