How a Digital Photocopier Works

igital photocopier technology has replaced thethan your original document.
analog photocopier in the workplace. Staff are noThe Technical Stuff
longer queuing in the copy room to reproduceInside your digital photocopier is a photoreceptor,
their documents, they request a lot of theirthis is a light sensitive surface consisting of a layer
copying and printing from the comfort of theirof photoconductive material that is attached to a
office chair! The advanced digital technology isdrum. In the dark the photoreceptor in insulating
better for the environment than old, analogbut expose it to light and it becomes conducting.
machines and they are easier to maintain andHigh voltage produces an electrical field near
repair. Combining the functions of a photocopier,adjacent wires causing ionisation and create an
laser printer, a scanner and a fax machine theelectric field across the photoreceptor.
digital photocopier has claimed a valuable place inThe image is scanned by a laser or a diode image
the office where one machine has replacedbar, the areas of the photoreceptor that are
several. A digital photocopier is a wise investmentexposed to the light are discharged causing a
for any workplace.reduction in the electric field. The darker areas
Old school, or analog (Xerography), photocopiersretain charge.
work by combining a positively charged drum andToner is the powder used to develop the image.
negatively charged substance called toner toToner is composed of colourant and plastic resin,
reproduce the image of the original document.the particles have electrostatic properties.
The original document would have to beMagnetised carrier beads transport the toner to
rescanned for each copy required. Digitalthe development area where they are charged
photocopiers scan the original document once andby static electricity (triboelectricity). The
store the data as a file on its hard drive so thephotoreceptor sends a electrostatic force to the
document can be reprinted easily and it can evencharged toner, this causes the toner to 'stick' to
be changed.the image.
The printing function of the digital photocopier isThe image is transferred to paper by the toner
very like a modern laser printer. The printercoming in contact with paper and applying a polar
efficiently memorises the document scanned andcharge opposite to that of the toner. A second
creates the page in the raster memory. Throughcharge releases the paper from the
lenses and mirrors, a laser reproduces the imagephotoreceptor, the image is now on the paper.
on paper, which is then made visible through tonerTo fuse the image the toner comprising the
with an opposite charge.image is melted and stuck to the paper. This is
Image quality is usually considerably higher on aachieved by passing the paper through rollers. A
digital copier than an analog model. The advancedheated roll melts the toner, which is fused to the
scanning technology means that duplicates can bepaper with the assistance of pressure from the
indistinguishable from the original document. If thesecond roller.
original document is not clear or faded, digitalThe advanced capabilities of a digital photocopier
copiers have facilities that enable you to changemake them faster, quieter and produce better
the intensity for the copies resulting in yourquality reproductions than traditional, analog
duplicates being of a far more superior qualityphotocopiers.