Which reproduction technique uses an electrostatic charge to duplicate an original?

The technique that uses an electrostatic charge to duplicate an original is xerography. This method involves creating an image using electric fields to attract toner particles to specific areas on a sheet of paper, resulting in a reproducible copy of the original document. The process begins with the original image being projected onto a photoreceptive drum, which is then charged with an electrostatic charge that corresponds to the light and dark areas of the original. Afterward, toner, which is also charged, adheres to the areas of the drum that have received a negative charge, creating a visible image that can be transferred onto paper through heat and pressure.

In contrast, the other choices do not specifically rely on an electrostatic charge for reproduction in the same way. Chemical printing involves processes that require chemical reactions and does not primarily utilize electrostatics. Photocopying can often be used interchangeably with xerography but encompasses various technologies that may not emphasize the electrostatic charge as its defining characteristic. Digital printing utilizes inkjet or laser technology but focuses more on direct transfer of digital images rather than electrostatic means. Therefore, the use of electrostatic charges to duplicate an original distinctly identifies xerography as the correct answer.