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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
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
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
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
Principle of thermal ink jet (HP)Principle of thermal ink jet (HP)
heat element
Nozzle plate
Gas bubble
ink
Typical thermal ink jet head (HP)Typical thermal ink jet head (HP)
Ink reservoircontacts
nozzles
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
Temperature profile in liquid/solid Temperature profile in liquid/solid interfaceinterface
Pulse energy as a function of thickness of Pulse energy as a function of thickness of passivationpassivation layerlayer
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
Lifetime vs. type and thickness of Lifetime vs. type and thickness of passivationpassivation layerlayer
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
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)
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 eye (cont.)Human eye (cont.)
Cones -- erythrolabe, chlorolabe and rhodopsinColor vision
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