Droplet jet application of adhesive to cigarette ends

An apparatus for applying a fluid capable of accepting an electric charge to a cigarette having a coal end portion which contains tobacco shreds, the cigarette being located in a groove on the perimeter of a rotating drum defining a path of travel which is perpendicular to the longitudinal axis of the cigarette, the path containing a sensor location and a target location, the apparatus comprising:

• a) a fluid supply connected to a nozzle to form a fluid stream,
• b) a vibrator which vibrates the nozzle to form droplets from the fluid stream,
• c) a droplet director for directing the droplets into the vicinity of a charging electrode,
• d) a voltage applicator connected to the charging electrodes which applies a series of voltages to the charging electrodes to cause a charge to be applied to at least some of the droplets, which applicator comprises
• i) a detector for detecting the presence of a cigarette on the drum as the cigarette passes the sensor location,
• ii) a start pattern signal generator which generates a start pattern signal beginning a period of time after the detected cigarette passes the predetermined sensor location, the period of time being equal in duration to the difference between the time required for the drum to move the detected cigarette from the sensor location to the target location and the time one of the series of droplets to travel from the point at which the droplets break from the fluid stream to the target location, and
• iii) a sequential voltage applicator which applies a sequential series of voltages of predetermined magnitudes to the charging electrodes at predetermined intervals in response to the start pattern signal to cause at least some the droplets passing in the vicinity of the charging electrode to be in proportion to the magnitude of the voltage applied to the charging electrode, and
• e) an electric field generating accelerator which deflects the charged droplets towards the target location in proportion to the charge on each droplet.

An apparatus for applying a predermined pattern of droplets of a fluid to an end of each of a series of cigarettes occupying at least some of a series of grooves located around the circumference of a cigarette drum having a variable rate of rotation, the fluid being capable of accepting an electric charge, the apparatus comprising:

• (a) means for generating a series of droplets of fluid;
• (b) means for passing the series of droplets in the vicinity of a charging electrode;
• (c) means for detecting incremental rotational movement of the cigarette drum;
• (d) means for generating a clocking signal in response to the detection of incremental rotational movement of the cigarette drum;
• (e) means for detecting the presence of a cigarette in a groove on the rotating cigarette drum as the groove passes a predetermined sensor location;
• (f) means for applying the clocking signal to a control circuit to cause a series of voltages to be applied to the charging electrode after the cigarette drum has rotated a predetermined number of increments following detection of the presence of the cigarette, whereby a charge is applied to at least some of the series of droplets passing in the vicinity of the charging electrode;
• and
• (g) means for passing the series of droplets through an electric field to cause the charged droplets to be deflected at an acceleration in proportion to the charge on each droplet and to cause at least some of the charged droplets to contact the end of the detected cigarette in a predetermined pattern as the detected cigarette passes through a predetermined target location.

A method for applying a fluid which is capable of electric charge to at least a portion of a coal end of a cigarette tobacco shreds, the cigarette being located in a groove on a perimeter rotatable drum, the rotation of the drum defining a predetermined path along which the cigarette moves in a direction perpendicular to the longitudinal axis of the cigarette, which path intersects a sensor and a target location, comprising the steps of:

• a) supplying the fluid to a nozzle to cause a stream of fluid to emerge from the nozzle,
• b) vibrating the nozzle to cause the stream of fluid to break up a series of droplets,
• c) directing the droplets into the vicinity of a charging electrode,
• d) detecting the presence of a cigarette on the drum as the passes a sensor location,
• e) generating a start pattern signal beginning a period of time after the detected cigarette passes the sensor location, the period of time equal in duration to the difference between the time required for the to move the detected cigarette from the sensor location to the target location and the time required for one of the series of droplets to from the point at which the droplets break from the fluid stream to the target location,
• f) sequentially applying a series of voltages of magnitudes to the charging electrodes at predetermined intervals in response to the start pattern signal to cause at least some of the passing in the vicinity of the charging electrode to be charged in proportion to the magnitude of the voltage then applied to the
• g) passing the charged droplets through an electric field to cause charged droplets to be deflected toward the target location at an acceleration in proportion of the charge on each droplet, wherein the timing of the voltages is synchronized with the movement of the along the predetermined path to cause at least some of the deflected charged droplets to contact the cigarette in a predetermined pattern as the cigarette moves across the target location.