What is Xerography? | What are its History and Benefits?

Xerography, known as electrostatic printing, utilizes dry electrostatics to duplicate documents or images. It uses static electricity to produce copies without wet ink or direct contact.

What is Xerography Technology and Its History?

Xerography is derived from Greek roots, which mean dry and writing. The term xerography means dry paper, reflecting its process. It differs based on chemical printing processes and utilizes photoconductivity. Photoconductivity is the ability of particular objects to conduct under light.

Silicon, germanium, and selenium absorb electrons from light, becoming weak electrical conductors. When voltage is applied, it enables the flow of electricity from atom to atom. Once the light is removed, they revert to being soft electrical conductors.

Xerography technology uses photoconductive selenium, aluminum, or other conductive metal backing layer.

Chester Carlson invented Xerography on October 22, 1938. Carlson graduated from the physics department and became a patent lawyer. In this job, he realized the need to create copies of documents quickly.

Later, Carlson experimented with materials that exhibited changes in electrical properties. These materials, known as photoconductive materials, were sensitive to electrostatic charges and light. In 1938, when he was 32 years old, he created the first xerographic image in his laboratory.

In 1947, Carlson discovered a small company in northern New York. With his invention, he acquired the rights to produce 4 billion pages of products. This technology later became the most widely used document printing method in offices.

How Does Xerography Work?

Static electricity charges the surface evenly. It is then exposed to light, which discharges or destroys the electric charge. This process leaves only shadow-charged areas.

It distributes powder pigment to the charged areas, making the image visible. Heat and pressure, then fix the ink on the form, completing the printing process.

Positive or negative ions electrostatically charge the layer. It depends on the polarity of the selected photoconductive insulating layer type. When a camera exposes the license plate, the light-receiving areas lose charges. So, this affects image capture and formation. It occurs based on the intensity they receive.

The charge retained on the plating layer creates an electrical or electrostatic model. So, this model represents and displays the image. The image forms when sprinkling a charged powder onto the exposed plate. This powder adds an opposite charge to the initial amount applied. In turn, it affects the plate and insulation layer.

The powder adheres to the charged areas, creating the print. Then, cover the plate with paper and apply a charge of the same polarity to the reverse side. So, this step helps in creating an electrostatic model. The dust image melts on the form when exposed to heat, thus fixing the image on the paper.

High-speed mechanized equipment performs all these operations in less than a second. Furthermore, the cost is cheap due to its reusable nature. As a result, the photoconductive insulating layer provides affordability.

Advantages and Disadvantages of Xerography

Advantages

Xerography is suitable for machines used in small, medium, or large offices. It allows text and graphics to be reproduced in seconds. It also offers variable image resolution for short to medium-sized jobs.

Users can use paper, cardboard, and transparencies easily without a CPU. Since the form does not need drying, users can feed it into the device. Additionally, the device provides support for stapling and double-sided printing.

Disadvantages

The main disadvantage of Xerography devices is that they use letter or A4 paper types. When the toner runs out, the printer leaves a blank white space. Additionally, users should allow some prints to cool as printouts may become extremely hot.