International Business Machines Corporation

Arthur R Hoffman

Thomas R Young

Gerald B Lammers

Robert Lewis Rohr

Gary L Fillmore

Arthur Harry Kendall

While present-day ink jet print heads are operable technically, they are too inconsistent and unreliable, and none has remained operational for as long as one year. The disclosure describes three structural improvements to these present-day ink jet print heads, any one of which offers a dramatic improvement over present-day head structures. However, if all three improvements described in the disclosure are included in the same print head, as high performance as 100% is available from those produced. The first improvement described relates to the gasket between the ink reservoir, with its nozzle plate attached, and the drop generator body that encloses the dynamic pressure transducer. If this gasket is formed of very soft material, having a durometer value in the order of 60, then it is only necessary to clamp the plate to the drop generator body with sufficient torque to seat and seal the ink reservoir to prevent ink leakage. The second improvement described requires a small space between each crystal in a piezoelectric transducer and the washer of acoustic-absorbing material, and the third improvement involves the support rod for these crystals. The support rod should fit with sufficient frictional force to retain the crystals in a preset position, avoiding all unnecessary extra loading of the crystals.

High performance ink jet print head for use in a high speed printer

An inner cylindrical tube has its outer cylindrical surface spaced from an inner cylindrical surface of outer means to have an ink cavity therebetween from which ink is supplied through one or more ink jet nozzles. At least the inner tube is a piezoelectric material so that the inner tube vibrates radially when electrically excited to produce vibrations at a desired operating frequency whereby a stream of ink droplets is supplied from each of the ink jet nozzles. The spacing between the inner surface, which has its longitudinal axis coaxial with the longitudinal axis of the inner cylindrical tube, of the outer means and the outer surface of the inner cylindrical tube is selected so that the ink cavity is resonant at the operating frequency of the inner cylindrical tube. To maintain the lowest frequencies of perturbations in the axial direction of the inner cylindrical tube substantially greater than the operating frequency, the inner cylindrical tube can be formed of a plurality of longitudinal segments acoustically isolated from each other in the axial direction. In another form, the outer means is a body formed with a membrane providing acoustical communication from a liquid cavity between the inner tube and the body and each ink cavity, which has ink jet nozzles at its end. The liquid cavity preferably has a liquid of substantially the same density as the ink. This enables each of the ink cavities to have a different colored ink if desired.

Ink jet head

A charge electrode array for a multi-nozzle ink jet array is fabricated from alternate layers of stainless steel and epoxy resin. The charge electrode array may be formed by positioning stainless steel tabs in previously grooved nonconductive substrate such as ceramic. The grooves are spaced sufficiently apart to allow insulating material to be placed between each stainless steel tab. Alternatively, a stainless steel plate may be bonded to a nonconductive substrate. Then the stainless steel can be sliced so that insulating material can be placed between each stainless steel strip. Epoxy fills the gap between tabs or strips forming an insulating layer. An ink drop charging channel through each tab or strip is formed by drilling through the tips of the steel tabs or strips, or by cutting U-shaped channels through the tips of the tabs or strips.

Charge electrode array for multi-nozzle ink jet array

A multi-nozzle ink jet array has all of the nozzles arranged in a single plane with each of the nozzles having a longitudinal passage extending therethrough of the same diameter. The lengths of the longitudinal passages of the nozzles at each end of the array are shorter than those in the center of the array to cause an increased initial velocity of the ink jet streams flowing therefrom so as to compensate for aerodynamic drag on the end streams.

Compensation for aerodynamic drag on ink streams from a multi-nozzle ink

Multiple nozzle arrays are formed from an assembly of at least one pair of plates having intersecting channels for receiving orifice elements and sealant. The joined plates, with inserted orifice elements in one channel and sealant in the other channel are then mounted vertically or at an appropriate angle and exposed to a temperature sufficient to cause the sealant alone to melt and to flow by capillary action to seal the orifice elements in a void-and-bubble free manner and to seal the plates to form a plate block. After cooling, the plate block is sliced into multiple nozzle wafers.

Growing community of inventors

Longmont, CO, United States of America

Arthur R Hoffman