We often use printers but, ever thought how it actually works? we select an image on PC and ask for a colour printer and boom you are done. You get an accurate copy of it in no time. Let’s see how..

Obviously first the printer transmits the data from the computer or data storage device as a digital file to the printer’s image processor.

Inside the printer, there is a drum that holds an electric charge. Next to the drum is a transfer corona roller, which can be negatively or positively charged as the drums requirement. In most laser printers, the drum starts out positively charged, although this process can also work in reverse. The controller throws out negative charge on the drum creating an “electrostatic image” of the digital file we chose to print.


Then, the drum is rolled on a positively charged toner. Which when rolled it sticks to the negative charged part of the drum, which is the projection of the image drawn.

The electrostatic image on the drum will transfer to the paper with more negative charge, Then it is fed through a fuser, which heats the toner and causes it to bind with the fibers in the paper.

It sounds great right. Here comes the more interesting part..

How colour is printed?

Printers have blue, red, black, yellow etc.. which can be combined to form any color. Some printers progressively lay the ink onto the drum so that the image will print with one pass of the paper( same process as specified above), while others recirculate the paper multiple times to apply progressive layers of color. Large color printers sometimes have separate drum and toner assemblies for each colour, with the paper passing each drum separately.

Well… Today 15th September is ENGINEERS day. So, Happy Engineers day.. Today is celebrated as Engineers day in the remembrance of  Sir Mokshagundam Visvesvaraya in India…

2 thoughts on ““LASER PRINTER” How it works?

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