Photocopiers may appear complex, but they work on two pretty simple pieces of science.
A drum that is coated with a special coating is the core of any photocopier. The paper is exposed to the bright light that is charged positively on the white areas and leaves the black parts negatively charged. The drum attracts the toner, which sticks to the paper, forming an inked impression.
Xerography
The technology that powers the majority of copy machines today is called the xerography. It’s a dry process made using electrostatic charge. Basically, it works by giving opposing electrical static charges the “ink” (a black powder referred to as toner), and then using heat to get them to stick to the paper.
Chester Carlson invented the xerographic method in his home laboratory in 1938. It transformed our work by permitting us to create large numbers of copies. While many big corporations did not like the idea at the time however, he was able to transform it into one of the most significant office technological innovations in the 20th century.
The sheet of paper that will be photographed is illuminated by a very bright light. The parts of the paper which have been printed – or marked with a symbol reflect light, whereas those that aren’t marked do. This causes electrons close to the surface of the drum to dissipate downwards, leaving behind a latent electrostatic image of the paper.
The next step is to apply a negative charge on the particles of toner. This is accomplished by passing the ‘ink’ through an electric field generated by corona wires. The negatively charged toner is attracted to the electric shadow of the photoconductor belt, and creates an inked duplicate of the original document. The paper from the other side of the belt gets a positive charge from an incline, and this draws the positively charged toner. The toner and the paper are melted under high temperatures. The result is that the copy the appearance of a permanent copy.
Photocopying Technology
Rather than printing out copies using ink, photocopiers utilize an electric charge to print the document on paper. The charge is produced by a rotating drum containing the reservoir that is filled with black powder, called toner. The drum is charged with one type of charge electrically and the toner has another – opposing charges draw each other. The drum is coated by a specific chemical that can capture the toner particles, and deposit them on a blank piece of paper.
The document that you want to copy can be placed in a slot at the uppermost part of the machine. A bright light scans the document looking for areas that are black. The scanner’s light reflects off these dark areas, creating an ‘electrical shadow’ on the page in a conveyor belt-like device called photoconductor.
Thue may photocopy hcm consists of a cylindrical object with a photoconductive coating. The drum gets positive charge through the laser of a printer or scanning system in scanner. It also exposes it a reservoir of carbon toner particles, which have the opposite charge. Toner adheres to exposed drum areas which are then heated and is bonded to the paper. The copy paper retains a bit of static electricity, which can sometimes cause the paper to stick in places it shouldn’t and cause jams. That’s why it is important to clean the paper surface of the copier frequently.
Photocopier components
The glass tray on which you can place your documents, is the most obvious component of a photocopier. There’s also the lamp, which shines a light on the document. And finally, there’s the drum, a rotating belt that is covered with a photo-conductive coating. Early copiers used selenium-based photoconductor. However, later models used selenium telluride. This metal converts light into electricity via the elimination of electrons in photoconductive atoms. If you shine a bright light on the original document more light will reflect off the unprinted white areas than the printed black regions. This causes an electrical shadow.
The document is then scanned by the optical scanner that creates an electronic image that the RIP transmits to the photocopier’s printing section. The print section is responsible for creating static electricity. it uses the same process as a photocopier analog to produce each line of text on the document. The document is printed by the drum using heat to make the ink.
It’s likely that you’ve seen static electricity in the past. Static electricity is what you get when you put a balloon in your clothes and then stick it on the wall. And the other scientific trick is the capability of certain materials to become more conductive when they absorb sunlight (photoconductivity). This is how xerography functions and is what makes most modern photocopiers the reliable and high-performance machines that they are.
Electrophotography
The key to the photocopying process is an electrostatic charge that is formed on a drum or other surface. The charge is generated by corona cables which are subjected to high voltage to generate an electric field between the paper and drum. Toner particles are positively charged and attract the negative charges of the paper. This creates an image.
Electrophotography, also referred to as xerography is the principle operation behind all laser and digital copy printers. Chester Carlson invented the process in 1937, and worked together with Battelle Memorial Institute on developing the technology into a product that could be used to be used in commercial settings. He created Haloid Corporation which became Xerox Corporation in the year 1961.
Two natural phenomena can be utilized in electrophotography. Materials with opposite charges interact with one another, and certain materials conduct more electricity when exposed to sunlight. Carlson created a six-step procedure for transferring images from one place to another making use of these natural phenomena.
First, the document is exposed to a photoreceptor. It is typically an instrument that is coated with a semiconductor which only conducts in the vertical direction. When the document is placed on top of a photoreceptor glowing light will be swung onto it. The light is reflected off the white parts of the document, and later transmitted through mirrors in order to illuminate the dark portions. The light reflected from the mirrors is transmitted through the photoreceptor, which releases the electric charge to the areas that are illuminated. Latent images are patterns of electric charges that appear on the photoreceptor.