These sparks are a discharge of electrical energy that has been generated from rubbing together two non-conductive surfaces - the phenomenon known as static electricity. Materials differ in their ability to generate static electricity, but many man-made fibres do so to a greater extent than natural fibres such as wool.

The quantity of electricity stored in a charge of static electricity is tiny by comparison with normal measurements. It leaks away readily unless the surfaces are very good insulators. Since water conducts electricity, high static charges usually occur only in low humidity environments. These may be due solely to the prevailing weather conditions (e.g. warm and dry or cold and frosty), or be additionally influenced by the presence of other equipment in the room or air-conditioning for the building.

The strength of the shock may be greater to a piece of electrical equipment because its exposed metal is likely to be connected direct to earth through its mains lead. There is therefore a lower electrical resistance than through an unearthed metal object such as a door knob or filing cabinet.

Shocks from the static charges built up in clothing are not hazardous. The build-up of charge can be minimised by a number of actions, such as increasing the humidity in the room, wearing clothes containing a higher proportion of natural or anti-static fibres, or avoiding actions that may generate a static charge - for example, a sleeve brushing repeatedly over a plastic surface. In severe cases, conductive footwear with floor mats or carpet sprayed with an antistatic fluid may be helpful. An alternative is to install a small touch-pad near the most common place where shocks occur. The touch-pad consists of a conductive surface connected by a high-value electrical resistor to a lead which is connected to earth. Touching this discharges the static on your body at a controlled rate which does not cause an irritating spark. Suitable items are available from office or computer supplies firms, sometimes as mouse-mats. They can be mounted on the Océ machine and connected to the machine chassis if desired.

Faulty Earth Connection
The increasing use of interference suppression filters in equipment containing electronic components has made any fault in the mains earth wiring more apparent. It can result in a mild electric shock (e.g. a `tingle'), unreliable machine operation or data corruption. It is ESSENTIAL that the earth is checked at the socket where the Océ machine is connected. This can be done by any qualified electrician. The Line-to-Earth voltage must be equal to the Line-to-Neutral voltage. The Neutral-to-Earth voltage must be zero.