Abstract: A substrate (10; 110; 210; 310) for an ink jet printhead comprising: at least three slots (12a, 12b, 12c) of elongated shape, oriented parallel to one another lengthwise in a vertical direction (13); three corresponding actuating banks (16a, 16b, 16c); a plurality of drive circuits (18); and a plurality of terminals (21, 21a, 21b), lesser in number than the ejection actuators (16), connected to the drive circuits (18) for receiving external signals, wherein at least two (12a, 12b) of the three slots are arranged side by side along the respective long edges in an upper portion (10a) of the substrate, and the third slot (12c) is arranged in a lower portion (10b) of the substrate, and wherein moreover the terminals (21) connected to the drive circuits are arranged in a line along the edges (11a, 11b) of the substrate (10) parallel to the slots and therefore to this given vertical direction (13). This substrate has a robust structure and is less likely to crack in the zone of the slots.

Abstract: This invention relates to a printhead in which a plurality of resistors are selectively activated by an external control circuit to produce the ejection of droplets of ink through nozzles located in correspondence with the resistors. Selection and activation are performed according to a matrix having a plurality of vertical lines corresponding to the number of resistors per group of nozzles and a plurality of horizontal lines corresponding to the number of groups of nozzles in the head. The groups of nozzles in the polychromatic head comprise real nozzles and fictitious nozzles, as a result of which the groups of nozzles have a regular layout, and are uniformly distributed and equivalent to the corresponding layout of a monochromatic head. With this solution, polychromatic heads having the same number and the same disposition of contacts with the external circuit and the same height as a monochromatic head can be manufactured simply.

Abstract: A substrate (10; 110; 210; 310) for an ink jet printhead comprising: at least three slots (12a, 12b, 12c) of elongated shape, oriented parallel to one another lengthwise in a vertical direction (13); three corresponding actuating banks (16a, 16b, 16c); a plurality of drive circuits (18); and a plurality of terminals (21, 21a, 21b), lesser in number than the ejection actuators (16), connected to the drive circuits (18) for receiving external signals, wherein at least two (12a, 12b) of the three slots are arranged side by side along the respective long edges in an upper portion (10a) of the substrate, and the third slot (12c) is arranged in a lower portion (10b) of the substrate, and wherein moreover the terminals (21) connected to the drive circuits are arranged in a line along the edges (11a, 11b) of the substrate (10) parallel to the slots and therefore to this given vertical direction (13). This substrate has a robust structure and is less likely to crack in the zone of the slots.

Abstract: This invention relates to a printhead in which a plurality of resistors are selectively activated by an external control circuit to produce the ejection of droplets of ink through nozzles located in correspondence with the resistors. Selection and activation are performed according to a matrix having a plurality of vertical lines corresponding to the number of resistors (1) per group of nozzles and a plurality of horizontal lines corresponding to the number of groups of nozzles (P) in the head. The groups of nozzles (P) in the polychromatic head comprise real nozzles ( 1, 27, 53, 79, 131, 157, 183, 235, 261, 287) and fictitious nozzles (105, 209), as a result of which the groups of nozzles have a regular layout, and are uniformly distributed and equivalent to the corresponding layout of a monochromatic head. With this solution, polychromatic heads having the same number and the same disposition of contacts with the external circuit and the same height as a monochromatic head can be manufactured simply.

Abstract: In a thermal ink jet printhead, an emission resistor includes a layer of electrically conductive material for making connections to the resistor. A temperature sensor and a reference temperature sensor, provided for detecting the temperature of enucleation of a bubble and used to directly determine the amount of energy needed for the emission resistor to effectively reach the temperature of enucleation, are arranged in correspondence with an integrated test resistor identical in construction to the emission resistor. The temperature sensor is formed from the layer of electrically conductive material. A differential amplifier having inputs connected to the temperature sensor and the reference temperature sensor effects regulation of a variable duration of pulses applied to the emission resistor.