The history of the photocopier began to be written in 1938, when an American physicist named Chester Carlson saw the need to make copies of documents quickly and easily, since he practiced law and was an inventor in his spare time. Carlson began his experiments with electrostatic charges and photoconductive materials, that is, materials that change their electrical properties when exposed to light, but the first results were not very good and companies like IBM or General Electric rejected his patent.

It was in 1938 when the process invented by Carlson was called “xerography”, and then, a small American company called the Haloid Company acquired the rights to this invention in 1947, after in 1944 the Battelle Memorial Institute in Ohio signed a Agreement with Carslon to develop Xerography. Ten years later, the company would be renamed Xerox Corporation. Shortly after, in 1950, the Radio Corporation of America, introduced a variant in the process, in which a paper specially designed for the purpose of photocopying was used, and finally, in 1959, the first photocopier in history was commercialized, the Xerox 914.

The development of the photocopier can be summarized in two parts: the first photocopiers were electrostatic, in which the image to be reproduced is projected directly onto the paper, whose surface is sensitized with electrical charges. The paper is then subjected to a toner bath and the particles are fixed in the electrified areas of the latter, giving rise to the final copy. The second part of the photocopier can be summarized with the color photocopier, developed by the Cannon company in 1973, and the first laser photocopier, also developed by Cannon in 1986.

The photocopying process consists of the original document being scanned by a beam of intense light that projects the image onto a rotating drum with a photosensitive surface (this is electrostatically charged in correspondence with the image). A pigmented powder (toner) is distributed on the drum that adheres to the electrified areas (where there is an image), reproducing the original writing or drawing. The thus pigmented image is transferred from the drum to the paper placed in the photocopier, which is finally heated to permanently fix the pigment on the copy.

Photocopying internally…!!!

Basically, analog photocopiers use many components and follow the following principle to produce a copy or document output:

Photocopying (Organic photoconductor drum).

This is where the actual image of the document being copied is produced. The drum is a hollow aluminum alloy cylinder coated with a light-sensitive organic photoconductor.

Loading the photocopy drum

A charging crown located and mounted on the top of the drum evenly deposits a strong negative charge across the entire surface of the drum. This makes the drum surface more sensitive to light.

Developing (LED exposure)

After charging, any area of the drum that is not used to produce an image will be neutralized. Most analog copiers use LEDs (light emitting diodes) to do this job.

To further illustrate, if your analog copier can make photocopies of documents up to A3 (297x420mm) and you are photocopying only an A4 (210x297mm) size document, all areas outside of the document size will be neutralized.

This is done to conserve toner usage.

Exposure to light

Light from the scanner lamp is directed towards the drum through a series of mirrors and lenses.

The light reflected from the scanned document strikes the surface of the drum reducing the amount of negative charge deposited by the corona charge assembly.

This process creates an invisible mirror image of the scanned document and will be seen in the next step.

Toner supply and development

The developer roller of the developer unit, in constant contact with the drum, supplies positively charged toner into the drum.

Only the areas of the drum surface that have been exposed to the light from the scanner will be filled with toner.

This forms the visible mirror image of the scanned document on the drum surface.

Feeding paper for the documentPhotocopying the document

This step feeds paper coming from the trays (cassettes) or bypass tray of the photocopier. The paper being fed is transported under the drum where the following process takes place.

Transfer and Separation

The mirror image created on the drum surface is transferred to the paper surface.

This creates an exact duplicate image of the scanned document and is done through the image transfer assembly installed under the drum.

The transfer corona emits a negative charge that attracts the positively charged toner from the drum surface.

As the image is transferred, the leading edge of the paper separates or peels away from the drum surface.

This is done by the separation corona which emits a charge to neutralize the paper that naturally separates it from the drum.

In addition, separation projections (also called claws) are installed under the drum to assist in this work.

Drum cleaning and toner recycling

Untransferred toner left on the drum surface during the developing process is physically scraped off with a rubber blade.

A spring coil mechanism transports the scraped toner back to the developer unit and then to the developer roller.

However, some models do not have a recycling mechanism and dispose of the untransferred toner as waste.

Drum neutralization

After cleaning the drum, small lamps are lit to neutralize the drum surface in preparation for the loading process.

paper fusing and output

The separated paper from the drum is transported to the fusing unit, where the image transferred to the paper surface is permanently fused.

Inside the fusing unit, fusing rollers apply heat and pressure to accomplish this process.

This is as if asphalt will be applied to the road surface and then steam laminated for a smoother finish.

Photocopying Transport Photocopying device

The paper is then transported to the output tray or sorting tray.

As the circumference of the drum is not sufficient to produce a full page of the scanned document, the whole process is repeated continuously until the complete image of the entire document is produced.

In addition, the scanner lamp is continuously illuminated per page of the document being scanned. This is one of the main distinguishing features of analog copiers.

But this feature had been eliminated and more features had been introduced in the development of digital copiers.

Digital printing

Day after day the digital is taking ground in the reading plane, however, with all the saturation of content that there is and due to distractions sometimes it becomes necessary to go back and use a good paper to concentrate and make an interesting and in depth reading.

Other times we need to have or carry certain physical documents from one place to another, it is there where the paper of a good quality photocopier is indispensable for a good photocopying.

Our digital printing is in London, 199 Walworth Road London SE17 RL we can make a multitude of copies in color or black and white with excellent quality and market prices.