Hewlett-packard Company

Data Products Corporation

Other

Hewlett-packard Corporation

Howard H Taub

Si-Ty Lam

Paul H McClelland

John D Meyer

Suraj L Hindagolla

Peter H Wolf

James S Aden

Glen A Hopkins

Gordon D Denler

Christopher A Schantz

David K Donald

Alfred I Pan

John L Vaught

William J West

Robert J Miller

Frank L Cloutier

Harold W Levie

Joan P Gallicano

A thermal inkjet printer is operated in a spray-mode by deliberately firing ink droplets from a printhead while the meniscus of the remaining ink in the printhead is settling down. Generally, the drops will not travel in a direction perpendicular to the printing surface. By calibrating the printhead, one can determine how many drops are needed to be fired within the boundaries of a pixel to achieve any given optical density. Drops may be fired at rates above 50 kHz, and, depending on the ink, above 70 kHz. Ink with a viscosity of 10 centi-Poise or less, and even 2 centi-Poise or less, may be used. When one is printing both text and non-text images on the same surface, a digital representation of an image to be printed is analyzed and divided into non-text image fields and text fields. Each non-text image field is printed on the printing surface by projecting the corresponding ink droplets in the spray-mode. Each text field is printed on the printing surface in a text-mode, in which the firing rate is typically reduced to 5-10 kHz and the corresponding ink droplets are projected substantially perpendicular to the printing surface.

Spray-mode inkjet printer

Selected portions of the orifice plate surfaces are formed to have wetting and non-wetting surface characteristics for minimizing the accumulation of residual ink on the outer surface of the plate and for enhancing the flow of supply ink to the orifices of the plate.

Orifice plate for an ink-jet pen

An inkjet printhead including a flexible substrate having at least one fold therein such that a first section of the substrate overlies a second section of the substrate. Inkdrop ejection chambers are disposed between opposed surfaces of the first and second sections of the substrate. Ink inlet orifices are provided in the first section of the substrate and each of the ink inlet orifices are in fluid communication with a respective one of the inkdrop ejection chambers. Ink outlet apertures are provided in the second section of the substrate and each of the ink outlet apertures are in fluid flow communication with a respective one of the inkdrop ejection chambers.

Printhead and a method for the manufacture thereof

An ink fill slot 18 can be precisely manufactured in a substrate 12 utilizing photolithographic techniques with chemical etching. N-type &lt;100&gt; silicon wafers are double-side coated with a dielectric layer 26 comprising a silicon dioxide layer and/or a silicon nitride layer. A photoresist step, mask alignment, and plasma etch treatment precede an anisotropic etch process, which employs an anisotropic etchant for silicon such as KOH or ethylene diamine para-catechol. The anisotropic etch is done from the backside 12b of the wafer to the frontside 12a, and terminates on the dielectric layer on the frontside. The dielectric layer on the frontside creates a flat surface for further photoresist processing of thin film resistors 16.

Anisotropically etched ink fill slots in silicon

A method of manufacturing a thermal ink jet printhead wherein a reusable mandrel consisting of either a metal pattern on an insulating or semiconductive substrate or an insulating pattern on a metal substrate or metal layer is used in the process of electroforming a plurality of metal substrates used for starting a batch fabrication process. Next, thin film layers of insulating, resistive, and conductive materials are formed on the surfaces of the metal substrates to thereby define heater resistors and lead-in conductors for the plurality of thermal ink jet printheads being formed. Then, a barrier layer such as Vacrel is photodefined on the surface of the thin film insulating, resistive, and conductive layers to thereby define a plurality of ink drop ejection chambers surrounding each of the previously formed heater resistors. Next, a plurality of orifice plates are secured, respectively, to the barrier layers in each of the printheads being formed. Finally, the plurality of metal substrates may be removed from the mandrel, such as by stripping away, without the requirement for substrate dicing, and an appropriate mask on the mandrel may be used to create an ink feed hole in each of the metal substrates. The metal substrates are further provided with a break tab line during the electroforming process which is aligned with break patterns in both the above thin film layers and orifice plates. In this manner, the individual thin film printheads may be easily broken away and separated one from another.

Process for manufacturing thermal ink jet printheads having metal

An orifice plate is thermally bonded to a thick film photopolymer spacer fabricated on a print head substrate using heat and compression. The compression is applied by pressurized gas to a pliable sheet covering the orifice plate and substrate assembly. Heat can be supplied through a vacuum chuck on which the assembly is mounted or from a heating element embedded in the pliable sheet. An apparatus comprising an air actuated ram with a flange having an o-ring seated within is used to seal the pliable sheet against the vacuum chuck circumferentially about the assembly. The ram includes a chamber with an open end which is sealed against the pliable sheet when in an engaged position. By filling the chamber with gas under sufficient pressure while heating the spacer forms a bond between the orifice plate and the assembly. After thermal bonding, curing of the photopolymer spacer can be completed in an oven.

Thermal-bonding process and apparatus

A thermal ink jet head incorporates bubble-generating resistors, each with a relatively thick layer of unpassivated resistive material, such as TaAl. The thermal ink jet head includes an ink source, ink channels, respective orifices, and circuitry for providing the electrical energy which the resistors convert to heat to form bubbles which expel ink through respective orifices. A range between 3,000 .ANG. and 5,000 .ANG. is preferred for the resistive material to minimize failure rate while avoiding thermal, electrical and manufacturing limitations of passivated resistors.

Ink jet head incorporating a thick unpassivated TaAl resistor

A three-sided barrier structure (22), comprising three walls (24a-c), is provided in conjunction with a resistor (10) used in a thermal ink-jet printhead. Placement of the structure less than about 25 .mu.m from the resistor results in longer resistor life and an improvement in the static bubble purging ability of the printhead.

Barrier structure for thermal ink-jet printheads

Off-setting the orifice (20) from the resistor (10) in a thermal ink-jet printhead provides improved print quality by controlling misdirection of first drops (26), second and subsequent drops (28) in multidrop printing, and for satellite drop control.

Thermal ink-jet head structure with orifice offset from resistor

A thermal ink jet printer is disclosed in which ink droplets are ejected from an orifice by the explosive formation of a vapor bubble within the ink supply due to the application of a two part electrical pulse to a resistor within the ink supply. The electrical pulse comprises a precurser pulse and a nucleation pulse; the precurser pulse preheats the ink in the vicinity of the resistor to a temperature below the boiling temperature of the ink so as to preheat the ink while avoiding vapor bubble nucleation within the ink supply and the subsequently occuring nucleation pulse very quickly heats the resistor to near the superheat limit of the ink.

Thermal ink jet printer

An improved impulse jet head structure utilizing etched silicon as the body of the structure. A silicon substrate is etched so as to form a nozzle groove, cavity, and ink supply groove. A layer of glass or other material is bonded to the top of the substrate so as to enclose the cavity and define, along with the grooves, and ink supply conduit and a nozzle conduit. A second layer of glass or other material is bonded to the bottom of the substrate and comprises the bottom surface of the cavity. A piezoelectric crystal driver is bonded to the bottom layer in a position corresponding to the location of the reservoir. An ink supply tube is bonded to the upper layer in a location above the supply groove and delivers ink to the head structure. The etching process may be utilized to form either single or multiple orifice head structures.

Impulse jet head using etched silicon

An improved ink jet print head structure. The print head includes a cylindrical glass rod having a bore extending along the axis of the rod. A surface is ground on the rod parallel to and near the bore. A metal organic paste is fired on the surface and a piezoelectric driver plate is soldered to the paste. A silicon nozzle plate is bonded to the front of the rod by means of an anodic bonding technique. The head structure may be attached to a charging electrode by means of an insulating support member, resulting in a prealigned and easily replaceable unit. Several alternative embodiments of the head structure and means for attaching the structure to an input line are disclosed.

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San Jose, CA, United States of America

Howard H Taub