Parts of a Copier – Labeled Diagram, Inside and Out

All 15 parts on the diagram

Show the list

Scanning 6

Automatic document feeder (ADF) Feeds a stack of originals one sheet at a time. Each goes to the glass's scanning area. Many feeders also turn two-sided originals over.
Platen glass An original is placed face down on it. Books and thick originals are copied from the glass, not the feeder.
Lamp It lights the original from below. The light the page reflects carries its image. The lamp moves along under the glass to cover the whole page.
Lens It carries the image of the original onto the image sensor. The mirrors bring the image to it.
Image sensor (CCD) Reads the image of the original and turns it into electrical signals.
Control panel Has the keys, display and indicator lights for working the machine.

Printing 9

Paper cassette It holds the stack of blank paper. It is also called a paper drawer or paper tray.
Bypass tray Paper is fed by hand from here. It is used for stock that does not go in the cassette, such as envelopes, labels and transparencies.
Charger (corona wire) Gives the drum's surface an even electric charge. This is done before the image is written on it. It is a high-voltage wire, called a corona wire, or a charge roller.
Drum (photoconductor) Its coating holds an electric charge in the dark. It loses the charge where light falls. A laser writes the image on it as a pattern of charge, which the toner then sticks to.
Toner cartridge It holds the toner, a fine powder. When the toner runs out the cartridge is pulled out and a new one put in.
Developer roller It is coated with toner and carries it to the drum. There the toner sticks to the charged image and makes it visible.
Transfer roller The paper passes between it and the drum. It pulls the toner image off the drum onto the paper.
Fuser A heat roller and a pressure roller. Together they melt the toner and bond it to the paper. Some makers call it the fixing unit.
Output tray The finished copy comes out here.

How this list was compiled: Every name checked on 2026-09-30, a name kept only where two independent sources use it. (1) Wikipedia, text only: Photocopier (corona wire or charge roller, photoconductive drum, lamp, toner, heat and pressure rollers, the digital copier as a scanner and a laser printer), Xerography (lens, developer roller, fuser), Laser printing (toner cartridge, developer roll, transfer roller, fuser), Automatic document feeder (platen) and Image scanner (image sensor, CCD). (2) Three unrelated makers' documents, read as full text on the Internet Archive: a digital copier service manual, https://archive.org/details/manualsbase-id-385889 (copy lamp, mirrors, lens, CCD image sensor, OPC drum, main charger, developing roller, transfer roller, heat roller and pressure roller, paper exit tray); a copier user's guide, https://archive.org/details/manualzilla-id-7427008 (feeder, platen glass, toner cartridge, drum unit, fixing unit, paper drawers and cassettes, stack bypass, output tray, control panel); and a second copier user guide, https://archive.org/details/manualsonline-id-fdd782c9-c528-4b22-8281-6a077531880a (automatic document feeder, original glass, cassette, stack feed bypass, output tray, control panel). Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry; no maker's machine, nothing traced. Licence: own work

How it works

The parts of a copier in two views. The top half scans the original: feeder, platen glass, lamp, lens and image sensor. The bottom half prints the copy: drum, toner, transfer roller, fuser and the paper trays.

Read the full guide

Follow the light, then the paper

In the top view a dashed line follows the light: the lamp lights the page on the platen glass, and mirrors send its image through the lens to the image sensor. In the bottom view a dashed line follows the paper: out of the cassette or the bypass tray, between the drum and the transfer roller, through the fuser and up to the output tray. Numbers 9 to 12 put the toner on the drum: charger, drum, toner cartridge, developer roller.

A digital copier is a scanner on top of a laser printer, which is why its bottom half has a drum, toner and a fuser.
Thick or bound originals go on the platen glass; loose sheets can go through the feeder.

Questions and answers

How does a copier work?

A lamp lights the original and a sensor reads it. The drum is charged, the image is written on it and toner sticks to the image. The toner is transferred to paper, then melted onto it by the heat and pressure rollers of the fuser.

What is the glass on a copier called?

The platen glass, or just the platen. The original lies face down on it to be scanned. Some makers' guides call it the original glass.

What is the ADF on a copier?

The automatic document feeder. It takes a stack of originals and feeds them one sheet at a time to the scanner, so a many-page document can be copied without placing each page by hand.

What does the fuser do in a copier?

It fixes the toner to the paper. The paper passes between a heat roller and a pressure roller, which melt the toner powder and bond it to the sheet.