Abstract: A linear array ink jet assembly is disclosed which includes a writing fluid source feeding a drop projection means which ejects a series of droplets of writing fluid from a nozzle in a discontinuous stream with sufficient velocity to traverse a substantially straight trajectory to a recording medium. The volume of each droplet is individually controlled by electrical pulses applied to the projection means from an electronic driver. A plurality of such projection means may be employed and connected to control means whereby to print or form predetermined graphical intelligence patterns on a recording medium.

Abstract: A recording apparatus and method is disclosed which includes a writing fluid source feeding a drop projection means which ejects a series of droplets of writing fluid from a nozzle in a discontinuous stream with sufficient velocity to traverse a substantially straight trajectory to a recording medium. The volume of each droplet is individually controlled by electrical pulses applied to the projection means from an electronic driver. A plurality of such projection means may be employed and connected to control means whereby to print or form predetermined graphical intelligence patterns on a recording medium.

Abstract: An ink supply connection to both an interchangeable print head and the ink supply container of an ink jet printer system of the asynchronous, volume displacement droplet ejection type, the ink supply including means for automatically closing off the ink supply line to prevent either the loss of ink or the introduction of air into the container, supply and print head when either the print head or the container is removed from the system. The print head includes an ink supply pressure sensor for sensing the changes in pressure in the system and a valve operated by the sensor to supply ink to the system upon reduction of the pressure below a predetermined level.

Abstract: A carriage and raceway mechanism for an ink jet printer upon which carriage is mounted an ink jet print head for driving the ink jet print head back and forth along the raceway to allow the ink jet print head to eject droplets on a recording medium. The raceway and various other functions are designed and combined into the main frame of the mechanism for simplified construction of the mechanism and lower manufacturing costs. Means for locking the carriage against movement and means for capping and purging the ink jet print head are also provided.

Abstract: An advancing mechanism for a recording web, such as paper, for an ink jet printer. The apparatus, including a platen having coaxially mounted discs on a shaft with the center disc of much higher coefficient of friction than the remaining discs, a tensioning roller, a pinch roller, and a recording web holding means, is self-aligning and self-threading, having low power requirements. Means for indicating the exhaustion of the recording web is also provided.

Abstract: An ink supply system for an ink printer having a pressurizable, interchangeable ink cartridge, means for pressuring the ink cartridge upon insertion into the ink cartridge receptacle, and means for establishing fluid communication between the interior of the ink cartridge and the ink supply line to the ink jet printer before pressurization of the ink cartridge occurs. The present ink supply system also includes an improved septum and needle method of establishing fluid communication.

Abstract: An optical encoder of the type having a fixed and rotating disc adjacent each other with superimposed varying light transmission patterns, such as slits, wherein one or more light beams are passed therethrough and the light pattern detected is an indication of the relative rotation between the fixed and rotary disc. A special optical element is located on one side of the fixed and rotary discs while the light source, detectors and electronics are located on another side of said discs. The optical element is a single solid optically clear piece of material with certain outside surface areas selectively positioned with respect to the light beams at angles for either total reflection or total transmission in a manner to provide a desired optical path.

Abstract: An electronic circuit for driving an ink jet print head of the type wherein a droplet of ink is ejected from an ink chamber through an orifice upon demand by pulsing a piezoelectric element in a manner to suddenly reduce the volume of the chamber. Switching circuits responsive to a low level control signal cooperatively energize the piezoelectric element for the duration of a control pulse and discharge the inherent capacitance of the crystal at the end of the control pulse. A storage capacitor is connected in a way to reduce the current drain on the power supply. Critical semi-conductor switching elements are provided with variable biases to maximize their switching speed.

Abstract: An electronic circuit for sensing and controlling the pressure and temperature of ink within an ink jet print head. Ink pressure is monitored by a pair of strain gauges electrically connected into a bridge whose output controls an ink supply valve. Part of that bridge is utilized with additional elements to form a second bridge for monitoring through one of the strain gauges the temperature of the ink jet head, accompanied with a heater of the head that is driven from the temperature signal to maintain the head temperature above a preset temperature.

Abstract: An interchangeable head system for an ink jet printer of the asynchronous, volume displacement droplet ejection type in which the print head is mounted on the print head carriage in a manner such that it may be readily detached and replaced with another head; the print head mounting allowing for adjustment of the distance from the print head nozzle to the print receiving medium. The ink supply connection to both the print head and the ink supply container includes means for automatically closing off the ink supply line to prevent either the loss of ink or the introduction of air into the container, supply and print head when either the print head or the container is removed from the system. The print head includes an ink supply pressure sensor for sensing the changes in pressure in the system and a valve operated by the sensor to supply ink to the system upon reduction of the pressure below a predetermined level.

Abstract: A recording apparatus and method is disclosed which includes a writing fluid source feeding a drop projection means which ejects a series of droplets of writing fluid from a nozzle in a discontinuous stream with sufficient energy to traverse a substantially straight trajectory to a recording medium. The volume of each droplet is individually controlled by electrical pulses applied to the projection means from an electronic driver. A plurality of such projection means may be employed and connected to control means whereby to print or form predetermined graphical intelligence patterns on a record medium.