A copier is a device capable of print, scan, copy functions and may include fax capability. Devices range in size from desktop models to room-sized equipment capable of producing tens of thousands of documents per day.

A copier, also known as a photocopier or copy machine, is a vital office tool designed to replicate documents and images quickly and efficiently. It employs various technologies to create duplicates of the original content onto sheets of paper, providing a convenient way to reproduce documents for distribution, record-keeping, and archival purposes.

The copier works by scanning the original document using a light-sensitive sensor, which converts the image into an electronic signal. This signal is then transferred onto a photoreceptor drum coated with a photoconductive material. The drum is charged with static electricity, and the charged areas attract toner, a fine powder that carries an electric charge. The toner is then transferred onto a sheet of paper and fused using heat or pressure, creating a replica of the original document. Modern copiers often include features such as duplex printing (printing on both sides of the paper), color copying, and the ability to scan documents directly to digital formats, making them versatile tools for various office tasks.

The history of copiers dates back to the early 20th century, with the first significant advancements in the mid-1900s. The Xerography process, invented by Chester Carlson and commercialized by the Xerox Corporation in the late 1950s, revolutionized document reproduction. Xerography uses electrostatic principles to transfer toner onto paper, allowing for the creation of fast and high-quality copies. The Xerox 914, introduced in 1959, became the first commercially successful plain-paper copier and marked a pivotal point in office technology.

Over the years, copier technology continued to evolve, with improvements in speed, image quality, and additional features. Digital copiers emerged in the 1980s, integrating computers for better control and flexibility in document reproduction. The transition to multifunctional devices in the late 20th century combined copier capabilities with printing, scanning, and faxing functionalities, further streamlining office workflows and increasing efficiency.