How is a photocopy made?

Photocopies Are Made From an Original

• When a copy is made, there must first be an original work to copy. Depending on the copier used, the original work may be virtually any size or shape, and may be only black and white or contain thousands of colors. To place the original on the copier, a user simply lifts the copier lid and placed the original face-down on the copy surface; for originals that consist of more than one page, though, some photocopiers provide a tray for stacking the multiple pages. If a tray is used, a series of rollers and conveyers pull each page onto the copying surface one at a time, then return them to the pile when the copy has been made (in such machines, a small component is inserted on the top of the stack to mark the end of the queue).

• When an original document or image is placed on the copy surface and the photocopier is activated, an electronic scanner is passed over the original to acquire an electronic image (also known as a digital picture) of the copied item. To illuminate the original document without creating shadows or distorting any colors in the image, a greenish light (chosen for its color accuracy) is projected onto the original as the photoimaging device passes over it. Depending on the quality or build of the photocopier, it may take as little as a second for the imaging device to pass over the original, or it may take upward of a minute for lower-priced home copiers to complete the scan.

• After a photocopier completes its scan of the original document, it feeds the electronic image to a printing mechanism. Depending on the make and model of the photocopier, the printing mechanism may work much like a home inkjet printer or may use commercial-quality laser printing techniques. In inkjet copiers, generally found on lower-end and consumer machines, a cartridge of ink is passed over blank copy paper; as the cartridge is moved, ink is sprayed onto the blank paper in precise increments in order to re-create the copied image. In higher-end copiers, a laser focuses light onto a drum of toner in the form of the digital image scanned in Section Two above. As the blank paper passes over the toner drum, the heated, excited toner particles adhere to the paper in a re-creation of the scanned image. Regardless of the technology used, the photo duplication--or photocopy--of the original document or image is re-created on blank copy paper and presented to the waiting user.