High density interconnect apparatus for an ink jet printhead

Ink jet printhead apparatus removably connectable to an electronic driver operative to output piezoelectric driving signals through a spaced series of electrically conductive exterior side surface areas disposed thereon, said ink jet printhead apparatus comprising:

• a mounting plate member having top and bottom side surfaces, front end edge surface and rear end edge surface opposite side edge surfaces extending between said front nd edge surface and said rear end edge surface, and an elongated top side surface groove disposed between said opposite side edge surfaces and longitudinally extending rearwardly from said front end edge surface to a rear end location spaced forwardly of said rear end edge surface;
• an ink jet printhead having a body received in said groove and secured to said mounting plate member, said body having a front-to-rear length and further having:
• a front end section with a spaced series of ink discharge orifices extending rearwardly therethrough, said front end section being adjacent said front end edge surface of said mounting plate member,
• a spaced, parallel series of internal sidewall sections extending rearwardly through a longitudinally intermediate portion of said body from said front end section and laterally bounding a spaced series of internal ink receiving channels interdigitated with said sidewall sections and opening outwardly through said discharge orifices, an opposing pair of said sidewall sections being piezoelectrically deflectable toward one another to constrict a channel which the opposing pair of said sidewall sections laterally bound to thereby force ink received in said channel outwardly through one of said ink discharge orifices,
• a rear end portion extending rearwardly beyond said longitudinally intermediate portion of said body, toward the rear end of said groove, and having an upper side surface essentially flush with said top side of said mounting plate member, and
• a mutually spaced first array of electrically conductive areas, formed on said upper side surface and operatively connected to said internal sidewall sections, through which piezoelectric driving signals are transmitted to said internal sidewall sections, said first array of electrically conductive areas having a first spacing density;
• and
• a multi-tiered printed circuit board secured to said top side of said mounting plate member and having:
• a bottom side surface having a first portion positioned against said upper side surface of said printhead body, and a second portion extending along and positioned against said top side of said mounting plate member, and a top side surface,
• a mutually spaced second array of electrically conductive areas formed on said first portion of said bottom side surface of said printed circuit board, said second array of electrically conductive areas being in registery with and fixedly and conductively secured to, said first array of electrically conductive areas,
• a mutually spaced third array of electrically conductive areas formed on said top side surface of said printed circuit board, said third array of electrically conductive areas having a second spacing density less than said first spacing density, and
• a mutually spaced series of electrically conductive crossover circuit paths formed within an interior of said printed circuit board and operatively interconnecting said second and said third array of electrically conductive areas,
• said mounting plate member being movable toward and away from the electronic driver in a manner respectively engaging said third array of electrically conductive areas with said electrically conductive exterior surface areas on the electronic driver and disengaging said third array of electrically conductive areas from said electrically conductive exterior surface areas on the electronic driver.