Uses of static electricity

3 marks · Normal

Describe, using ideas about static electricity, how static charges are used in photocopiers.

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A drum or plate is charged, and when light reflects off the original image, the charge is lost where light strikes. Toner particles, which are given a charge, stick to the charged areas. The toner is then transferred to paper and heated to fix the image.

Also accept: Drum is charged; image exposes part; charged toner attracted to non-exposed areas; then transferred to paper

Common mistakes: Not referencing the use of charge

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Marking points

B1 · 1 mark · Drum is charged by static electricity.

B2 · 1 mark · Light removes charge from exposed regions.

B3 · 1 mark · Toner with opposite charge sticks to remaining charged areas, transferred to paper and fixed by heat.

Worked solution

Photocopiers use a drum that is charged by static electricity. Where light strikes the drum (white areas of original), the charge leaks away. Toner particles, which have the opposite charge, are attracted to the charged (unexposed) areas. The toner image is transferred onto paper and fixed by heat.