1. Inkjet Printing Inkjet Technology Fundamentals Rafi Bronstein Rafi
Inkjet Printing Inkjet Technology Fundamentals Rafi Bronstein Mobile:

2. Inkjet Technology and Inkjet Printing
Rafi Bronstein
2008

3. Course Syllabus Inkjet technology history and fundamentals
Types on inkjet technologies
History of inkjet printing
Industrial applications
Most successful inkjet printing technologies
Continuous inkjet technologies
Drop-on-Demand inkjet technologies
Thermal inkjet
Piezo inkjet
Novel ink ejection technologies

4. Course Syllabus Print head fabrication materials and processes
Print head designs and key vendors
Thermal inkjet
Piezo inkjet
Direct ink ejection
Piezo print head design parameters
Frequency, crosstalk, drop placement accuracy …

5. Course Syllabus Printing inks and their composition
Ink types and properties
Inkjet printing substrates
Paper and coatings
Non-paper media
Basics of radiometry and basic color theory
Radiometry
Color systems and color management

6. Course Syllabus Ink drying and curing technologies
Drop-on-demand ink droplet deflection techniques
Sony
Kodak
Others

7. Course Syllabus Inkjet printing systems design The printing industry
Digital printing and inkjet printing

8. Ink Jet Printing Methods Classification

9. Ink Jet Printing History (I)
1878 – Lord Rayleigh
1929 – Hansell, USP #1,941,001 Electrostatic Deflection Recorder
1938 – Genschmer, USP #2,151,683 Spark Type Ink Ejector
1946 – Hansell, USP #2,512,743 Jet Sprayer Actuated by Piezoelectric
1958 – Winston, USP #3,060,429 Drop Jetting by Electrostatic Attraction
1962 – Naiman, USP #3,179,042 Sudden Steam Printer
1964 – Sweet, USP #3,596,275 Continuous Inkjet Printing
1966 – Hertz et al. USP #3,416,153 Modulation by Electrostatic Dispersion
1967 – Sweet et al. USP #3,373,437 Array of Continuous Ink Jets

10. Ink Jet Printing History (II)
1970 – Kyser et al. USP #3,946,398 Drop-on-Demand Bend Mode Inkjet Apparatus
1970 – Zoltan, USP #3,683,212 Squeeze Tube Piezoelectric Inkjet
Stemme – USP #3,747,120 Bend Mode with Metal Diaphragm
1979 – Endo et al. GBP #2,007,162 Electrothermal Transducer (Bubble jet)
1982 – Howkins, USP #4,459,601 Piezoelectric Push Mode
1982 – Vaught et al. USP #4,490,728 Electrothermal Transducer (Thermal Inkjet)
– Fishbeck, USP #4,032,929 - USP #4,584,590 Shear Mode Transducer
1989 – Bartky et al. USP #4,879,568 Droplet Deposition Apparatus

11. Ink Jet Printing Continuous Drop-On-Demand (DOD) Others Piezoelectric
Thermal (Bubble) inkjet
Others

12. Lord Rayleigh – Drop Formation Law (I)V P L λ
Emerging from an orifice liquid jet breaks-up into droplets. Because of the surface tension:
Droplets have random size
Droplets have random spacing

13. Lord Rayleigh – Drop Formation Law (II)
L = K*ln(d/2α0)V(ρd3/σ)0.5
λ = 4.51d; fs = V/4.51d d V P L λ
α0 – the initial disturbance
ρ - the density of the fluid
σ – the surface tension of the fluid
L – break-up length
fs – the frequency of spontaneous drop formation
λ – wave length

14. Drop Formation – Ink Jet Basics
Can the drop size be controlled?
Can the spatial spacing of the drops be controlled?
Can the break-up length be controlled?
What would be the drop selection method?

15. Sweet-type Continuous Ink Jet
Deflection
Plates
Pressure
Charge
Electrodes
Gutter
Substrate

16. Binary Continuous Ink Jet
Deflection
Plates
Pressure
Charge
Electrodes
Gutter
Substrate

17. Is It So Simple?
                                                                              
Change in Viscosity
with pressure
Viscosity
Density

18. Drop Charging Methods Plate Charging (Sweet) Tunnel Charging
(S. Bahl?)
Plate Face Charging
(S. Bahl?)

19. Drop Charge Requirements and Limits
Drop charge limits:
(Rayleigh limit)
Q = Sq.Rt.(64π2ε0r3σ);
ε – free space permittivity
σ – surface tension
r – drop radius
Electric field between the
electrodes
Conductive ink
Inductive charging
Charging voltage
Charging electrode shape
Jet break-up parameters

20. Drop Deflection L Electrostatic deflection field
Plates
Pressure L
Charge
Electrodes
Gutter
Substrate
Electrostatic deflection field
Aerodynamic drag force
Neighboring drops repulsion
Deflection on paper X = (qE/mV2)L(D-(L/2))
Where q, m, and V are charge, mass and drop velocity. L- length of the deflection plate. D – distance from the plate edge to the substrate.

21. Density modulation (W. Lloyd & H. Taub)
Substrate
Substrate
Mask
Mask
Charge
electrode
Substrate
Charge
electrode
Nozzle
Mask V V
Drop dispersion on
mask/aperture
Charge
electrode V

22. Density modulation (H. Hertz)
Deflection
Plates
Pressure
Charge
Electrodes
Gutter
Substrate
Variable number of drops per pixel

23. Key Inkjet Patents (I)

24. Key Inkjet Patents (II)
Zoltan

25. Piezoelectric Materials
Ceramics poling

26. Piezo effect and Piezoelectric Deformation- + + -

27. Piezoelectric Materials (I)

28. Piezo effect and Piezoelectric Deformation- + + -

29. Elements of Piezoelectric Inkjet technology
Source: S. Negro and E. Smouse, Hewlett-Packard Inkjet Printing Technology: The State of the Art, 1999

30. Key Inkjet Patents (III)

31. Drop-on-Demand Piezoelectric Inkjet
Piezoceramic
Membrane
Manifold
Pressure
chamber
Orifice
Inlet
Orifice plate

32. Drop Ejection Process
Drop Ejection Process:
Push-on
Draw-push

33. Forces Acting on Ink Drop
VCarriage
Drop charge
Electric field of the substrate
Ejection frequency
Nozzle plate state …
VDrop
Windspeed H
Drug d
daero

34. Elements of Thermal Inkjet (print head structure)
Source: S. Negro and E. Smouse, Hewlett-Packard Inkjet Printing Technology: The State of the Art, 1999

35. Elements of Thermal Inkjet (how it works)
Source: S. Negro and E. Smouse, Hewlett-Packard Inkjet Printing Technology: The State of the Art, 1999

36. Elements of Thermal Inkjet (drop ejection process)
Source: S. Negro and E. Smouse, Hewlett-Packard Inkjet Printing Technology: The State of the Art, 1999

37. Thermal Inkjet Configurations
Source: S. Negro and E. Smouse, Hewlett-Packard Inkjet Printing Technology: The State of the Art, 1999

38. Key Inkjet Patents (IV)
Canon

39. Key Inkjet Patents (V) HP

40. Key Inkjet Patents (VI)
Fishbeck

41. Key Inkjet Patents (VI)
Fishbeck

42. Key Inkjet Patents (VII)

43. Key Inkjet Patents (VIII)
Bibl
MicroFab

44. Key Print Head Characteristics
Resolution
Drop ejection frequency
Drop volume
Drop speed
Array pitch
Drop speed uniformity across the array
Operating temperature range
Physical size and weight

45. Print Head Resolution – Print Resolution
Pitch between two neighboring nozzles
Actual resolution
Linear array
Two dimensional array
Electronic resolution
Minimal printable distance between two successive dots

46. Drop Ejection Frequency
Minimal time between two successive drop ejection cycles
System resonance
Fixed frequency
Plurality of ink ejection frequencies
Defines throughput

47. Drop Speed The speed at which the drop leaves the orifice
Aerodynamic resistance
Multi drop grey scale printing
Ejection force
Ink parameters
Defines printing speed
Drop speed variations

48. Effect of Drop Speed Variations

49. Drop Volume The volume of the ejected drop (picoliter; nanogram)
Drop volume variation
Drop volume variation as function of ejection frequency
Defines amount of ink on the substrate and accordingly image color gamut

50. Tektronix Print head US Pat. No. 5,155,498

51. Drive Signal Form US Pat. No. 5,155,498

52. Various Drop Formation Wait Periods. Signal of Fig. 2. US Pat. No

53. Drop Flight Speed with Signal of Fig. 2. US Pat. No. 5,155,498

54. Another Form of Drive Signal US Pat. No. 5,155,498

55. Print Head Pressure Changes with Drive Signals of Figs. 6-7. US Pat. No. 5,155,498

56. Crosstalk Between the Channels

57. Drop Volume as Function of Ejection frequency US 5,274,400 (HP)

58. XAAR XJ500/360. VEEjet.

59. Q&A
Do you have any questions?

60. Thank you