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
Print technology in the 1970Print technology in the 1970’’ss
Impact printing – Slow– Noisy– Expensive– Not “all points addressable”
paper
Color ribbon
Print hammer
Print typeback printing
Principle of Impact printingPrinciple of Impact printing
Typical Impact printerTypical Impact printer
Typical impact printerTypical impact printer
Alternative technologies: impact free Alternative technologies: impact free printingprinting
Laser printingInkjet printing– Continuous ink jet– Drop-on-Demand inkjet
Continuous ink jet technologyContinuous ink jet technology
continuousOnly 3 percent of drops are usedHigh drop rate Ink sump requiredInk must be cleaned
Continuous ink jetContinuous ink jet
““All points addressableAll points addressable”” print technologyprint technology
Multi nozzle print headMulti nozzle print head
Ink jet printer with multi nozzle print headInk jet printer with multi nozzle print head
DropDrop--onon--Demand Inkjet Demand Inkjet TechnologieTechnologie
Drop-on-DemandDrop only created if drop is neededLow drop rateMulti nozzle head is needed
DropDrop--onon--Demand drop generatorDemand drop generator
Drop generator according to Drop generator according to StemmeStemme
DropDrop--onon--Demand PrincipleDemand Principle
Drop formation in DropDrop formation in Drop--onon--Demand InkjetDemand Inkjet
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
Inherent contradiction of ink jet technologyInherent contradiction of ink jet technology
Ink shall never dry in the nozzleInk shall be dry on paper instantaneously
Schematic of inkjet print head (Schematic of inkjet print head (HeinzlHeinzl))
PT 80 ink jet print headPT 80 ink jet print head
Principle of thermal ink jet (HP)Principle of thermal ink jet (HP)
heat element
Nozzle plate
Gas bubble
ink
Thermal ink jet print headThermal ink jet print head
Typical thermal ink jet head (HP)Typical thermal ink jet head (HP)
Ink reservoircontacts
nozzles
Typical thermal inkjet head Typical thermal inkjet head (HP, Cannon)(HP, Cannon)
Typical ink jet printer (HP)Typical ink jet printer (HP)
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.
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
HP print headHP print head
Schematic of ink jet nozzleSchematic of ink jet nozzle
Schematic of nozzle and resistorSchematic of nozzle and resistor
Heater fluid interfaceHeater fluid interface
Temperature profile in liquid/solid Temperature profile in liquid/solid interfaceinterface
Temperature profile in heater and fluidTemperature profile in heater and fluid
Temperature profile in thermal printerTemperature profile in thermal printer
Pulse energy as a function of thickness of Pulse energy as a function of thickness of passivationpassivation layerlayer
Drop ejectionDrop ejection
Simulation of drop ejectionSimulation of drop ejection
Typical ink jet print head (again)Typical ink jet print head (again)
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
Fabrication stepsFabrication steps
Resistor structureResistor structure
Pinholes cause reliability problemsPinholes cause reliability problems
Lifetime vs. type and thickness of Lifetime vs. type and thickness of passivationpassivation layerlayer
PassivationPassivation micro cracksmicro cracks
Next step: Fabrication of orifice plateNext step: Fabrication of orifice plate
Layout of orifice plateLayout of orifice plate
Nozzle and barrier wallNozzle and barrier wall
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
Mandrel fabricationMandrel fabrication
Schematic of electroformingSchematic of electroforming
Electroforming of orifice plateElectroforming of orifice plate
Front view of nozzle plateFront view of nozzle plate
Back view of orifice nozzle plateBack view of orifice nozzle plate
Print head after assembly (again)Print head after assembly (again)
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.
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)
DodDod discrete print head driversdiscrete print head drivers
Drop velocity vs. pulse widthDrop velocity vs. pulse width
DodDod discrete print head driversdiscrete print head drivers
Design of color print head (1980)Design of color print head (1980)
Epson Piezoelectric print Epson Piezoelectric print headhead
Planar piezoelectric elementsCommercially availableNot a bubble jet
Color perceptionColor perception
Three requirements– Light source– Object with pigment– Observer
Human eyeHuman eye
Human eye (cont.)Human eye (cont.)
Cones -- erythrolabe, chlorolabe and rhodopsinColor vision
Perception spectrumPerception spectrum
Color propertiesColor propertiesHue, Saturation, Lightness (Brightness) (HSB)
Color properties (cont.)Color properties (cont.)
Red, Green, Blue (RGB)Cyan, Magenta, Yellow, Black (CMYK)
Additive / Subtractive mixingAdditive / Subtractive mixing
Computer Monitors, TV’s -- AdditivePrinters, photographs -- Subtractive
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
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