Ink jet printhead and its manufacturing process

Process for manufacturing an ink jet printhead, comprising the steps of:

• preparing ejector modules, each including:
• a chip substrate having a front surface and a top surface,
• a plurality of resistors arranged parallel to the top surface of the chip substrate,
• a plurality of ejection cells located above the resistors,
• delivery channels to deliver ink to the ejection cells,
• a main distribution channel, defined in the top surface of the silicon chip, the main distribution channel extending orthogonally to the delivery channels, and along the front surface of the chip substrate without interruptions, and
• a nozzle layer having ejection nozzles aligned above the resistors and adjacent to an edge of the module, said ejection nozzles being parallel to the resistors and the top surface of the chip substrate
• providing a support having an ink feeding duct for one or more modules, the ink feeding duct being in fluid communication with the front surface of the chip substrate and the main distribution channel;
• mounting the module or modules on said support so as to have the main distribution channel or channels in fluid communication with said feeding duct;
• hydraulically sealing the nozzle layer of the module or of the modules from said support, for ink-tightness in feeding the ink between the feeding duct and the nozzles through said delivery channels;
• making an etching on a given face of the chip substrate to produce said main distribution channel extending along the front surface of the chip substrate without interruptions;
• producing sacrificial volumes for defining the limits of the ejection cells above the resistors and the delivery channels above the area;
• applying a structural layer over said sacrificial volumes to define said nozzle layer;
• wherein said etching step produces on said face, in addition to the main distribution channel, a series of ribs that extend transversely across the main distribution channel between the delivery channels and the main distribution channel to form a further distribution channel orthogonal to the main distribution channel and in fluid communication with both said delivery channels and said main distribution channel, and in which a part of the sacrificial volumes extend into the space between said ribs and on said main distribution channel,
• further wherein a part of the structural layer is applied on the ribs and remains fastened on said ribs after removal of the sacrificial volumes.