Parts of a Document Scanner

Components of a Document Copier

A document copier comprises various essential components that facilitate its efficient operation. Among these key parts are:

Paper Tray

This component functions as a drawer or container that holds the paper intended for printing.

Paper Feed Mechanism

This part consists of a rubber-element mechanism designed to pull a sheet of paper from the paper tray and transport it to the printing system, starting from the designated registration roller.

Registration Roller

The registration roller is made of a soft rubber cylinder that collects the paper and feeds it toward the imaging drum.

Exposure Lamp

Typically found in older copier models, the exposure lamp provides illumination to the original document, allowing the light to reflect through a series of lenses and mirrors before projecting the image onto the drum.

Photo Drum

The photo drum is an aluminum cylinder coated with a light-sensitive film. This film reacts to light exposure, forming an image on the drum through a pattern of positively and negatively charged areas, thereby creating static electricity.

Charge Corona

Commonly referred to as “Charge Corona,” this component consists of a thin wire situated within a metallic housing. Its primary function is to generate an electrical charge on the drum’s surface, facilitating the interaction of light with the photosensitive film and attracting positively charged toner particles to the drum.

Toner Unit

This unit contains finely ground colored plastic powder that transforms into toner during the copying process. It also includes a “developer,” a chemically processed metallic substance that is electrically charged. As the electrically charged drum passes through the toner unit, the developer attracts the toner to the drum.

Transfer Corona

Similar to the Charge Corona, the Transfer Corona consists of a thin wire within a metallic housing designed to electrically attract toner from the drum to the paper. At the same time, it helps separate the charged paper from the drum, allowing the document to move on to the next stage of the copying process.

Fuser Unit

This component’s primary function is to bond the toner to the paper. It consists of two rollers heated to melt the plastic in the toner, which is then released onto the paper as it passes through the rollers. The upper fuser roller is heated by a lamp that regulates the temperature.

Cleaning Unit

Designed to eliminate any residual toner and charges that may have accumulated on the drum, the cleaning unit comprises a magnetic roller and a specialized cleaning blade made from a silicone rubber strip connected to a metallic arc. This assembly makes contact with the drum’s surface to remove any leftover debris.

Paper Transport System

This system facilitates the copying process by employing a series of rubber rollers that ease the movement of the paper throughout the operation.

Output Tray

Also known as the “output tray,” this optional extension serves as the designated area for collected copies, allowing the paper to stack neatly and preventing any sheets from falling out.

General Information about Document Copiers

Document copiers were invented in 1937 and gained popularity in the 1950s. They are utilized for producing duplicates of written material, prepared printed documents, and various illustrations. The basic principle of operation involves a selenium-coated drum reflecting light onto the document intended for copying. Subsequently, negatively charged toner particles are sprayed onto the drum, forming an image of the document. As the paper passes over the drum, positively charged areas pull the negatively charged toner particles onto the paper, resulting in a transferred image.