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Ink Jet PrintingInk Jet Printing

Frank E. TalkeSpring 2008

MAE 268

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OutlineOutline

Review of Print Technology before 1980Principles of Ink jet technology– Continuous ink jet technology– Drop on demand ink jet technology

Design of drop on demand print headDiscussion of HP papers on design and manufacturing of drop on demand print head

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Print technology in the 1970Print technology in the 1970’’ss

Impact printing – Slow– Noisy– Expensive– Not “all points addressable”

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paper

Color ribbon

Print hammer

Print typeback printing

Principle of Impact printingPrinciple of Impact printing

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Typical Impact printerTypical Impact printer

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Typical impact printerTypical impact printer

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Alternative technologies: impact free Alternative technologies: impact free printingprinting

Laser printingInkjet printing– Continuous ink jet– Drop-on-Demand inkjet

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Continuous ink jet technologyContinuous ink jet technology

continuousOnly 3 percent of drops are usedHigh drop rate Ink sump requiredInk must be cleaned

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Continuous ink jetContinuous ink jet

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““All points addressableAll points addressable”” print technologyprint technology

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Multi nozzle print headMulti nozzle print head

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Ink jet printer with multi nozzle print headInk jet printer with multi nozzle print head

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DropDrop--onon--Demand Inkjet Demand Inkjet TechnologieTechnologie

Drop-on-DemandDrop only created if drop is neededLow drop rateMulti nozzle head is needed

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DropDrop--onon--Demand drop generatorDemand drop generator

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Drop generator according to Drop generator according to StemmeStemme

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DropDrop--onon--Demand PrincipleDemand Principle

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Drop formation in DropDrop formation in Drop--onon--Demand InkjetDemand Inkjet

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Technical difficulties of drop on demand Technical difficulties of drop on demand ink jet technologyink jet technology

Formation of gas bubblesChemistry of inkSmall drop ratesFabrication of a cheap and disposable print headLeaking of ink from nozzle

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Inherent contradiction of ink jet technologyInherent contradiction of ink jet technology

Ink shall never dry in the nozzleInk shall be dry on paper instantaneously

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Schematic of inkjet print head (Schematic of inkjet print head (HeinzlHeinzl))

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PT 80 ink jet print headPT 80 ink jet print head

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Principle of thermal ink jet (HP)Principle of thermal ink jet (HP)

heat element

Nozzle plate

Gas bubble

ink

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Thermal ink jet print headThermal ink jet print head

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Typical thermal ink jet head (HP)Typical thermal ink jet head (HP)

Ink reservoircontacts

nozzles

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Typical thermal inkjet head Typical thermal inkjet head (HP, Cannon)(HP, Cannon)

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Typical color printerTypical color printer

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Typical ink jet printer (HP)Typical ink jet printer (HP)

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SummarySummary

Ink jet printing is interdisciplinary Thermal ink jet head is a very complicated materials/mechanics deviceLittle information on fabrication of print head is available in the open literatureIn the following, we will discuss the fabrication and materials issues of the HP print head based on publications by HP.

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Discussion of HP papers on print head Discussion of HP papers on print head design and principles of color printingdesign and principles of color printing

Bubble jet (thermal jet)Use of semi-conductor technology for head fabricationHeating of planar resistor creates bubbles which collapseThrow away head (very important)Hp, Cannon, Lexmark, etc.Black and white and color

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HP print headHP print head

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Schematic of ink jet nozzleSchematic of ink jet nozzle

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Schematic of nozzle and resistorSchematic of nozzle and resistor

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Heater fluid interfaceHeater fluid interface

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Temperature profile in liquid/solid Temperature profile in liquid/solid interfaceinterface

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Temperature profile in heater and fluidTemperature profile in heater and fluid

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Temperature profile in thermal printerTemperature profile in thermal printer

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Pulse energy as a function of thickness of Pulse energy as a function of thickness of passivationpassivation layerlayer

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Drop ejectionDrop ejection

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Simulation of drop ejectionSimulation of drop ejection

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Typical ink jet print head (again)Typical ink jet print head (again)

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Fabrication of ink jet headFabrication of ink jet head

Nozzle plate is most critical partResistance heater and nozzle plate must be bonded and assembled with ink cartridgeDisposableRefillableLife time considerationscheap

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Fabrication stepsFabrication steps

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Resistor structureResistor structure

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Pinholes cause reliability problemsPinholes cause reliability problems

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Lifetime vs. type and thickness of Lifetime vs. type and thickness of passivationpassivation layerlayer

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PassivationPassivation micro cracksmicro cracks

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Next step: Fabrication of orifice plateNext step: Fabrication of orifice plate

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Layout of orifice plateLayout of orifice plate

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Nozzle and barrier wallNozzle and barrier wall

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Nozzle plate fabricationNozzle plate fabrication

Fabrication of nozzle plate is done by electro forming on a “mandrel “A mandrel has the inverse shape (negative) of the final nozzle plateFabrication of one mandrel (master) allows replication by electro forming of many nozzle platesPlated parts are removed and the master is re-used for repeated nozzle plate fabrication

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Mandrel fabricationMandrel fabrication

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Schematic of electroformingSchematic of electroforming

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Electroforming of orifice plateElectroforming of orifice plate

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Front view of nozzle plateFront view of nozzle plate

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Back view of orifice nozzle plateBack view of orifice nozzle plate

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Print head after assembly (again)Print head after assembly (again)

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DiscussionDiscussion

Hi tech part of printer is nozzle plateLaser can also be used for making holes for nozzleSilicon micro mechanics potentially “easy” but never commercializedPrinter does not “make money”, but the expendables like ink cartridges do.

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Color drop on demand ink jet print Color drop on demand ink jet print head design using piezoelectric head design using piezoelectric squeeze tubessqueeze tubes

(Lee, Mills, Talke, IBM Journal 1984)(Lee, Mills, Talke, IBM Journal 1984)

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DodDod discrete print head driversdiscrete print head drivers

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Drop velocity vs. pulse widthDrop velocity vs. pulse width

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DodDod discrete print head driversdiscrete print head drivers

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Design of color print head (1980)Design of color print head (1980)

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Epson Piezoelectric print Epson Piezoelectric print headhead

Planar piezoelectric elementsCommercially availableNot a bubble jet

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Color perceptionColor perception

Three requirements– Light source– Object with pigment– Observer

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Human eyeHuman eye

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Human eye (cont.)Human eye (cont.)

Rods -- rhodopsinNight vision

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Human eye (cont.)Human eye (cont.)

Cones -- erythrolabe, chlorolabe and rhodopsinColor vision

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Perception spectrumPerception spectrum

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Color propertiesColor propertiesHue, Saturation, Lightness (Brightness) (HSB)

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Color properties (cont.)Color properties (cont.)

Red, Green, Blue (RGB)Cyan, Magenta, Yellow, Black (CMYK)

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Object with pigmentObject with pigment

Subtractive scheme primary colors

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Additive / Subtractive mixingAdditive / Subtractive mixing

Computer Monitors, TV’s -- AdditivePrinters, photographs -- Subtractive

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Photo AlbumPhoto Album

by Home

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SummarySummary

Color printing has become accepted everywhereHuman eye is sensitive only to RGBAdditive primaries are complements to subtractive primariesAdvances bring high quality printing to the homeWithout mems technology, there would be no color printingTiming for technology is very important: without fast computers and high storage disks, color printing would not exist