Removal of protective liners from the media can cause static charge. The ionizer bar removes static charge to prevent print quality issues.
Usage of the ionizer bar is defined in the media profile, and the printer automatically enables or disables the ionizer bar based on the selected media profile. If you create a new media profile, you have to define in the profile whether you want to enable the ionizer bar.
For more information about media profiles, see Manage media profiles in ONYX.