In this ever-changing world, technological advancement is taking its toll on producing invaluable innovations that feeds the global system to become convenient, efficient, fast and quality all at one go. Touched with modernity, we are living the life where we make use of the fundamental discoveries and devices that comes along the pursuit of breakthroughs owing to the greatest minds that had/have set foot here on Earth. Chester Carlson was one of them—an American inventor and the one who gave birth to a revolutionary instrument we normally use these days called photocopy machine or photocopier. Although Carlson originally called the process electrophotography. Suffice to say, a photocopier plays an important role not only in the office and business affairs but to school, home and to somewhere else as long as you have something that you want to make a copy of. It could be a document, paper or an image of someone you like.. a selfie, perhaps?Yes, we get it. Photocopy machine is quite a trend today that leaves our paperwork fast, easy and pretty much convenient for our very own comfort. In short, it’s essential to the functioning of our demanding lives on a regular basis. But, how does it work? The mechanics of a photocopier are modest, but still somewhat complex.When using photocopier, we begin with a few basic steps: open the copier lid, place the document to be photocopied face-down on the glass, select the options you want (number of pages, enlargements, lighter/darker), and lastly, press the Start button—and there we have it! Out emits a page akin to the original one, though not perfectly the same. Cool, right? You bet it is! Anyway, what happens inside the copier at this point is even more amazing! At its heart, a copier works because of one basic physical principle: opposite charges attract. Static electricity and photoconductivity are also two of the scientific tricks that makes a photocopier work.Inside a copier there is a special drum. The drum acts a lot like a balloon—you can charge it with a form of static electricity. Inside the copier there is also a very fine black powder known as toner. The drum, charged with static electricity, can attract the toner particles. There are three things about the drum and the toner that let a copier perform its magic. The drum can be selectively charged, so that only parts of it attract toner. In a copier, you make an “image” in static electricity on the surface of the drum. Where the original sheet of paper is black, you create static electricity on the drum. Where it is white you do not. What you want is for the white areas of the original sheet of paper to not attract toner. The way this selectivity is accomplished in a copier is with light –this is why it’s called a photocopier! Somehow the toner has to get onto the drum and then onto a sheet of paper. The drum selectively attracts toner. Then the sheet of paper gets charged with static electricity and it pulls the toner off the drum. The toner is heat sensitive, so the loose toner particles are attached (fused) to the paper with heat as soon as they come off the drum. The drum, or belt, is made out of photoconductive material.Here are the actual steps involved in making a photocopy as per Meeker-O’Connell’s article: The surface of the drum is charged. An intense beam of light moves across the paper that you have placed on the copier’s glass surface. Light is reflected from white areas of the paper and strikes the drum below. Wherever a photon of light hits, electrons are emitted from the photoconductive atoms in the drum and neutralize the positive charges above. Dark areas on the original (such as pictures or text) do not reflect light onto the drum, leaving regions of positive charges on the drum’s surface. In other words, it will have a kind of “electrical copy” of your hand. This is the key to how a photocopier works. Negatively charged, dry, black pigment called toner is then spread over the surface of the drum, and the pigment particles adhere to the positive charges that remain. A positively charged sheet of paper then passes over the surface of the drum, attracting the beads of toner away from it. The paper is then heated and pressed to fuse the image formed by the toner to the paper’s surface. Viola! The final output is now ready!