Ion generator structure

A corona device for use in modifying an electrostatic charge on a dielectric receptor surface of a printer and the like, the corona device comprising;

• a housing for mounting on the printer;
• an ion generator for engaging the housing to rotate in the housing, the generator having more than one corona wire for use one at a time to provide ion generation to modify said charge;
• and
• indexing means coupled to the housing and the ion generator and including resiliently biased means for releasably engaging and locating the ion generator angularly with respect to the housing in one of a number of positions equal to the number of corona wires as the ion generator is rotated in the housing, the resiliently biased means arranged to permit rotation of the ion generator in only one direction relative to the housing so that the wires are used sequentially.

A replaceable ion generator for use with an electrostatic printer having a suitable ion generator housing, the generator comprising:

• a support rod;
• a plurality of corona wires attached to the support rod and spaced angularly about the support rod;
• a protector extending about the rod and spaced radially from the wires, the protector having an axially extending window;
• a bush located in the protector for rotatably receiving an end of the rod in spaced relationship to the protector;
• and
• an end piece fixed to another end of the rod and journalled with an end of the protector to allow angular movement of the rod relative to the protector so that selected ones of the wires can be aligned with the window at an exposed location, the window having an annular extent less than the spacing between adjacent wires so that the rod can be located in the protector with the wires out of alignment with the window in unexposed locations to minimise the risk of damage thereto during transportation and handling.