With the advent of technology, we are now exposed to the world of machines which helps us to do our work with less effort and time. One of the common technological equipment nowadays is the photocopier machine. It is used to generate another copy of an original print. Chester Carlson invented the process called xerography in 1938. The xerographic process is actually used to make both copies and prints. The word xerography is derived from the Greek word “Xerox” which means “dry writing”. This is then developed and commercialized by the Xerox Corporation which is widely used to produce high-quality text and graphic images on paper, thus, making the photocopier to be commonly called as “xerox machine”.Moreover, photocopier machines work under the principle of photoconductivity and Coulomb’s law; photoconductivity is the principle by which certain substances like carbon sulfide and selenium conduct, when light is being exposed to them, and the Coulomb’s law states that like charges repel while unlike charges attract.Looking at the machine macroscopically, we can observed that it produces a copy of printed material by just placing the document on the glass and covering it. Just a click on the button and then it will generate a photocopied paper. This is how we see it basically. But how did really the images are reproduced by the photocopier?Copying a document in a photocopier machine is actually based on two natural phenomena defined by Carlson. He proposed that materials of opposite electrical charges attract and that some materials become better conductors of electricity when exposed to light. He then invented a six-step process to transfer an image from one surface to another using these phenomena. First, there is a photoconductive surface which is given a positive electrical charge. The photoconductive surface is then exposed to the image of a document. Because the illuminated sections or the non-image areas become more conductive, the charge disperses in the exposed areas. Thus, negatively charged powder spread over the surface adheres through electrostatic attraction to the positively charged image areas. A piece of paper is placed over the powder image and then given a positive charge. The negatively charged powder is attracted to the paper as it is separated from the photoconductor. Finally, heat fuses the powder image to the paper, producing a copy of the original image.That is how photocopier machine works at the back of our naked eyes. It functions in a way that only science could explain.