Printing to the beat of a different drum
Jul 26th, 2010 by admin
Laser printing technology is deceptively simple. You use some software to create a digital image and a laser temporarily etches the image onto a round drum which picks up toner and transfers it onto paper which then passes through a heating source to “cure” it – simple, right? Wrong!
Let’s take it one step at a time:
- You create a digital image – this is actually a complex mathematical set of numbers describing each point in the image as a grid reference.
- Each of these grid references becomes an address for the laser beam to use to reproduce the image on the drum.
- The drum is given an electric charge as it rotates which is negated by the laser beam as it follows the instructions of the software to reproduce the image onto the drum.
- The drum picks up the toner in the areas which the laser has negated.
- An electrostatic charge on the clean paper then attracts the toner from the drum.
- The toner is then heat fixed onto the paper which is why it feels warm when it emerges from the printer.
When you next look at your laser printer cartridge consider also that the circumference of the drum is typically much smaller than the length of the paper receiving the image. This means that each time the drum rotates it is cleaned off and prepared to receive the next section of that particular page.
Generally, there are two configurations of drum units within printers. The smaller, lower volume, inexpensive laser printers usually have a combined toner and drum unit. This means that when you run out of toner ink you replace both the toner and the drum unit as one. The other configuration is where the printer has a separate toner unit to the main drum unit. This type of configuration is common with large scale, high volume and fast action laser printers. Only the toner unit needs replacing when you run out of printer ink. The drum unit is replaced less frequently – usually you will replace the toner cartridge 4 to 5 times before needing to replace the drum unit. When the drum unit needs replacing the printer / copier will send a warning message to the console.
Now you know all about laser printing. At least the black and white part of it! Doing it all in colour is a story we will save until another time!
Image Source:http://computer.howstuffworks.com

















