Tensionable ground electrode for fluid-jet marking apparatus

摘要

An electrode for use in a fluid-jet marking apparatus includes a flexible and tensionable electrode member mounted in confronting, substantially parallel alignment to a linear array of fluid droplet streams. The mounting of the flexible and tensionable electrode member is accomplished by a pair of mounting arms in spaced-apart relationship, one of the arms being pivotal while the other arm is immovable. The one pivotal arm is thus displaced relative to the other immovable arm so as to responsively tension the electrode member therebetween. In order to increase the vibrational frequency of the flexible and tensionable electrode member and/or to substantially decrease the vibrational amplitude thereof, at least one intermediate arm having a terminal end in operative contact with the electrode member is provided. The contact of the terminal end of the intermediate arm occurs at least one location along the electrode member between the pair of spaced-apart mounting arm members and thus essentially shortens the "free length" of the electrode member so that vibrational frequency of the electrode member is substantially increased thereby responsively substantially decreasing the vibrational amplitude of the electrode member towards and away from the droplet streams. In such a manner, the electrode member can be closely positioned laterally of the droplet streams. An alternative embodiment of the electrode structure employs an additional flexible and tensionable ground electrode ("ground shield") preferably composed of a flexible ribbon of electrically conductive material disposed directly beneath the deflection electrode and in a substantially opposed confronting relationship to the droplet catching structure.