Gravure "the modern intaglio printing "

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History and development
In the 19th century, a number of developments in photography allowed the
production of photo-mechanical printing plates. W H fox Talbot mentions in
1852 the use of a textile in the photographic process to create half-tones in the
printing plate. A French patent in 1860 describes a reel-fed gravure press. A
collaboration between Klic and Fawcett in Lancaster resulted in the foundingof
the Rembrandt Intaglio Printing Company in 1895, which company produced
art prints. In 1906 they marketed the first multi-colour gravureprint.
In 1912 Messrs Bruckman in Munich produced proofs for Bavarianpostage
stamps which went into production in 1914. Also in 1912 newspaper
supplements printed by reel-fed gravure were on sale in London andBerlin

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Irving Berlin's song "Easter Parade" specifically refers to these type of
supplements in the lines "the photographers will snap us, and you'll find that
you're in the rotogravure". And the song "Hooray for Hollywood" contains the
line "…armed with photos from local rotos" referring to young actresseshoping
to make it in the movie industry.
In 1932 a George Gallup "Survey of Reader Interest in Various Sections of
Sunday Newspapers to Determine the Relative Value of Rotogravure as an
Advertising Medium" found that these special rotogravures were the most
widely read sections of the paper and that advertisements there were threetimes
more likely to be seen by readers than in any other section.
Gravure is one of several printing techniques being actively used in thenew
field of printed electronics.

4. Printing Methods
Printing Technology is in widespread use.
Printing is necessary for modification, or improvement of the
substrate to make it more suitable.
Several Industries are based on Printing technology.
Adhesive coating , Printing, Flexible laminates are the few
examples.
The basic steps in continuous production of Printing substrates are
as follows.
1. Preparing the coating solution
2. Unwinding the substrate roll
3. transporting / passing it through the coater
4. applying the coating from the coating solution
5. drying the coating
6. winding the final coated roll
7. Converting the coated substrate to final size

5. Printing Methods
There are few other operations that are often used , such as,
a) surface treatment on the substrate to improve adhesion.
b) cleaning the substrate prior to coating , to reduce contamination
c) lamination with other substrate
Different types of Printing methods are used depending upon
the substrate as well as the end product requirement.

7. Printing Process
The application of a liquid Ink to the traveling web / substrate is
accomplished by one of the many coating methods. Widely used
Printing methods are , Gravure direct and or offset , Flexo ,
Screen, Letter Press , Digital, Inkjet, etc.
The choice of the method depends on the nature of the web/
substrate , the rheology of the Ink , the solvent the wetcoating
weight desired, the desired coating width and speed, the no of
layers or coating to be applied simultaneously , cost
considerations, environmental considerations .

8. Printing Process
The printing method should be chosen based on the specific
requirement. many a times a method is selected based on the
availability of a specific coating applicator.
even though it may not be the best choice. much time , money
and raw materials may be wasted by trying to make the product
by a process that is not suitable.
The printing method may be too narrow at the conditions
selected or it may be impossible even to obtain a quality coating.
A process that works well at low speed in laboratory or pilot
priter may not be appropriate for a manufacturing plant , coating
at high speeds . Similarly a high speed printing plant may not be
appropriate for laboratory trials.

9. Printing is a very Important
process involved in the Manufacture
of several intermediate or final
products

10. The selection of the best printing method for any
particular type of work depends on a number of
factors. The key factors that need to be considered are
as follows:
1. Type of substrate
2. The Thickness
3. Width of substrate
4. Full or partial printing
5. Handling after printing
6. Cleanup

11. 1. Digital Printing.
2. Flexography.
3. Letterpress Printing.
4. Offset Printing.
5. Rotogravure.
6. Screen Printing.

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Digital printing
Digital printing can be done in various ways. Twotechnologies
dominate the industry:
Inkjet – In an inkjet printer the image that needs to be printed is
created by small droplets of ink that are propelled from the nozzles
of one or more print heads. Inkjet devices can print on a widerange
of substrates such as paper, plastic, canvas or even doors and floor
tiles. Inkjet printing is used a lot for posters and signage. It is also
economical for short run publications such as photo books or small
runs of books. In-line inkjet printers are sometimes combined with
other types of presses to print variable data, such as the mailing
addresses on direct mail pieces. The press shown below is the HP
PageWide C500, meant for printing on corrugated board.

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Flexo
In flexography the content that needs to be printed is on a relief
of a printing plate, which is made from rubber. This plate is inked
and that inked image is subsequently transferred to the printing
surface. The process can be used to print on paper as well as
plastics, metals, cellophane and other materials. Flexo is mainly
used for packaging and labels and to a lesser extent also for
newspapers.
Some packaging printing is moving from flexo to digital.

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Letterpress
The first ever press was a Letterpress. It basically uses stamps to
grab ink and place it on the paper (or other material). Think of a
typewriter, but doing whole pages in one press. Of course, this
took long to do as each page was setup before by hand and
manually placing these letter stamps in place. As time went on,
full page stamps were created instead to make the process easier
(though still inefficient compared to other methods). Today
however, the Letterpress is not used much as it is not an efficient
and far too expensive method of printing.

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In offset lithography a printing plate, which is most often made
from aluminum, contains an image of the content that needs to be
printed. When the plate is inked, only this image part holdsink.
That inked image is subsequently transferred (or offset) from the
plate to a rubber blanket and then to the printing surface. The
process can be used to print on paper, cardboard, plastic or other
materials, but these have to have a flat surface.
Below is a picture of a 4 color sheetfed printing press. At the far
end is the intake where individual sheets of paper are
automatically fed into the press. The 4 towers or printing units
each print one color, typically black get printed first, followed by
cyan, magenta and yellow. The stack of printed sheets is visibleon
the front of the machine, underneath the press console & monitor
which the press operator uses to control the press.

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Offset is nowadays the
most widely used printing
technique for an extensive
range of products such as
books, newspapers,
stationery, corrugated
board, posters, etc.
There is a trend that
printing promotional
material is gradually
migrating to digital
printing while some
packaging printing is
moving to flexo.

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Gravure
Also known as rotogravure, this is a technique in which an image
is engraved into a printing cylinder. That cylinder is inked and
this ink subsequently transfers to the paper. Gravure is used for
high volume work such as newspapers, magazines, and
packaging.
Gravure is gradually losing market share to offset for publication
printing and to flexo for packaging applications.

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Screen printing
As its name implies, this printing technique relies on a
screen, which is a woven piece of fabric. Certain areas of
this mesh are coated with a non-permeable material. In
the remaining open spaces ink can be pushed through the
mesh onto a substrate. The advantage of screen printing
is that the surface of the recipient does not have to be flat
and that the ink can adhere to a wide range of materials,
such as paper, textiles, glass, ceramics, wood, and metal.

22. Selecting an appropriate coating method is a challenge because
there are currently many applicators in routine use and each of
these has unique capabilities in terms of the printing variables
that they can apply and the resulting coated substrateproperties.

23. Digital Printing.
Flexography.
Letterpress Printing.
Offset Printing.
Rotogravure.
Screen Printing.

24. There are a wide variety of technologies that are used to print
stuff. The main industrial printing processes are:
Offset lithography
Flexography
Digital printing: inkjet & xerography
Gravure
Screen printing
Additional printing techniques were developed for very
specific applications. These include flock printing, letterpress,
intaglio, pad printing, and thermography.

25. The gravure printing process relies on an engraved roller running
in a coating bath, which fills the engraved dots or lines of the roller
with the coating material.
The excess coating on the roller is wiped off by the Doctor Blade
and the coating is then deposited onto the substrate as it passes
between the Engraved roller and a Pressure Roller.
There are three different ways of gravure roll manufacturing . One
has to choose a correct type depending upon the required coating
gram mage and the material to be coated

26. Gravure Coating Capabilities
Viscosity Range
Web Width Range
Coat Weight Range
Substrates
: 10 - 2000 Cps
: 300 – 2500mm
: 1 – 5gsm (Offset Gravure)
: 3-20gsm (Direct Gravure)
: 10 – 100gsm(reverse Gravure)
: Paper, Film And Foil.

27. The Main Components:
Coating Tray / Pan
Gravure Roller (Etched Metal roller)
Doctor Blade
Impression Roll (Rubber roller)
The Process:
Pick up of Coating from the Pan
Fill up the Cells in the gravure roller
Wipe out the excess coating by Doctor Blade
Transfer the Coating to the Web
Empty the Gravure Cells after Transferring to Web

28. The Adhesive level has to
be maintained Constantly
The Foam generation has
Gravure
Roll
Adhesive IN Adhesive
OUT
to be minimized
No settling of Solids
This is Possible with some
of the tray Designs shown
in the figure
Gravure
Roll
Ink in
InkOUT

29. The Gravure Roller performs important Functions
Apply continuous and homogeneous coating across
and down the web
The etching pattern determines the coating weight
It is a driven toll to manage web tension
At times it is hollow with water circulation to maintain
coating temp and the viscosity of the coating

32. In low weight coating or printing, anilox is a method used to
provide a measured amount of ink to a flexo printing plate.
An anilox roll is a hard cylinder, usually constructed of a steel
or aluminum core which is coated by an industrial
ceramic whose surface contains millions of very fine dimples,
known as cells. Depending on the design of the printing press,
the anilox roll is either semi-submerged in the ink fountain, or
comes into contact with a so-called metering roller, which is
semi-submerged in the ink fountain. In either instance, a thick
layer of typically viscous ink is deposited on the roll. A doctor
blade is used to scrape excess ink from the surface leaving just
the measured amount of ink in the cells. The roll then rotatesto
contact with the flexographic printing plate which receives the
ink from the cells for transfer to the printed material.

33. The characteristics of an anilox roll determine the amount of
ink that will be transferred to the plate: angle of the cells,
cell volume, and line screen. A 60 percent angle ensures
maximum density in a given space. Lower volume makes for
less ink. Low line numbers will allow for a heavy layer of ink
to be printed, whereas high line numbers will permit finer
detail in printing. Both cell volume and line screen areclosely
correlated.
Anilox rolls are often specified by their line screen, which is
the number of cells per linear inch. These often range from
around 250 to upwards of 2000, though the precise numbers
vary by manufacturer. Most rolls sold are within 800 LPI,
although a spike in demand for those with 800-1200 lines has
been seen. Anilox rolls are almost always designed to be
removed from the press for cleaning and for swapping out with
different line screen rolls.

34. Depending on the detail of the images to be printed, the press
operator will select an anilox roll with a higher or lower line
screen. Low line screen rolls are used where a heavy layer of
ink is desired, such as in heavy block lettering. Higher line
screens produce finer details and are used in four-color
process work such as reproducing photographs. Often a job
will require a different line screen for each color to be printed.
Experienced press operators are skilled at determining the
appropriate anilox rolls for a given print job.
Though large wide-web flexo rolls are only maneuverable by
overhead crane, on smaller presses anilox rolls are often
handled directly by operators. Extreme caution must be taken
when handling these pieces of hardware as a single bump
against a hard surface or sharp corner can destroy the delicate
cell structure on the surface and render a roller completely
useless,

35. at a cost of around US$5000 for even small narrow-web
rollers. Nicks and scratches add up quickly, so fine brushes
(never brass brushes) are used for cleaning the anilox roll.
Similarly, anilox rollers that are used with water, solvent and
oil based inks, which dry when left sitting out and unagitated,
must be cleaned immediately after use or a problem known as
plugging occurs, where minuscule amounts of ink dry in the
cells. This leaves tiny, but unacceptable, pinholes in anything
printed from the roll in the future.
Anilox rolls were originally made using a diamond pecking
machine, but modern rolls are laser engraved.
Laser engraving, which is different from laser marking,[1] is
the practice of using lasers to engrave an object. Lasermarking
on the other hand just discolors the surface, without cutting
into the surface.

36. The technique does not involve the use of inks, nor does it
involve tool bits which contact the engraving surface and wear
out. These properties distinguish laser engraving from
alternative engraving or marking technologies where inks or
bit heads have to be replaced regularly.
The impact of laser marking has been more pronounced for
specially designed "laserable" materials and also for some
paints. These include laser-sensitive polymers and novel
metal alloys.
The term laser marking is also used as a generic term
covering a broad spectrum of surfacing techniques including
printing, hot-branding andlaser bonding. The machines for
laser engraving and laser marking are the same, so that the two
terms are sometimes confused by those without knowledge or
experience in the practice.

37. Laser engraving of anilox rolls
Prior to 1980 anilox rolls were produced by a variety of
mechanical processes. These metal anilox rolls were
sometimes sprayed with ceramic to prolong their life in
theflexographic printing press. During the 1980s laser
engraving systems were produced which used a carbon dioxide
laser to engrave the required cell pattern directly into the
polished ceramic surface. Since then Q-switched YAG lasers
were used for a period as they provided a more focusable laser
beam as well as increased pulsing frequencies capable of
engraving the finer cell configuration demanded by the ever
evolving flexographic printing process.

38. Since approximately the year 2000 the direct anilox laser
engraving process has been dominated by the use of fibre
lasers which provide the high powers of the carbondioxide
lasers together with the finely focusable beam of the YAG
lasers. Optical systems providing the rapid switching of
multiple beams have allowed the fibre laser system to be
dominant in this market. This technology has become known
as Multi-Beam-Anilox or MBA.

40. Type of
Engraving
Screen Cell Depth
mm
Deposit
gm/m2
Lines/in Lines/cm
Pyramidal 200
40
79
16
0.003
0.037
2.4
27.6
Quadrangular 200
16
79
6
0.005
0.065
3.6
49.5
Trihelical 120
24
47
9
0.010
0.055
11.7
63.1

41. Pyramidal cells
Quadrangular
Tri helical

42. QuadragravurePyramid
Quad Roto FloRoto-Flo Pyramid
Tri-Helical Quad Channel

43. Cell Properties
BCM: Volume
: 2 – 200 BCM
( Billion Cubic Micron
per Square Inch )
LPI: Cell Density /
Lines Per Inch
Release / TransferRate
: 10 – 1500 LPI
: % Coating Volume Released On to Substrate
Method of Cell Creation : MechanicalEngraving
Laser Engraving
Electronic Engraving

44. Depth=X
Breadth=Y
Depth=X-less
Depth=X-less
ImproveReleaseProperty

45. 30o Channel
60o Hex
Tri-Helical
30o Hex

48. Doctor’s blade Removes or Excess
Coating
Only the Coating filled up in the Cells
remains
Gravure
Roll
The Cell Determines the Coat Weight
Angle of Contact : Trailing Blade is
meant for
Low Speed / Low Viscosity
Hydraulic Forces Can Lift Blade
Traps Contaminates
Loading Pressure
0.5 – 4.0 pli

49. Reverse angle
Doctor’s blade Removes or Excess
Coating
Only the Coating filled up in the
Cells remains
The Cell Determines the Coat
WeightGravure
Roll
Angle of Contact : ReverseAngle
is meant for
Increased Speed and Viscosity
Hydraulic Force Helps Hold Blade
Rejects Contaminates
Loading Pressure
0.5 – 4.0 pli

50. Printing application methods
There are several coating methods, but three are the most commonlyused.
The blade coater rolls the liquid coating onto the bottom of the paper,then
uses a flexible blade to scrape away the excess coating. This method
produces a sheet with high gloss, but the resultant variation in coating
thickness can cause inconsistent ink holdout and produce uneven printed
solids (mottle).
The trailing blade coating method scrapes away excessive coating,but
leaves a thick-and-thin effect.
The trailing blade
coating method scrapes
away excessive coating,
but leaves a thick-and-
thin effect.

51. The Doctor Blade holder assembly looks like the figure
below
 Generally fitted with pneumatic movement
 The blade angle is changeable
 The blade Oscillation system is motor driven

52. This is a Rubber roller
Width of this roller has to be slightly lesser than
the web width
The Rubber should be of Hardness 60-65 ShoreA
Rubber Roller
WEB

53. The Hardness of the Roller has a Impact on the quality as
well as the quantity of coating
Higher Rubber thickness with a softer Hardness of around
60-70 shoreA , generally gives more coating weight
Lower Rubber thickness with a higher Hardness of around
80-90 shoreA , generally gives lower coating weight
For uniform coating across the web the Rubber roller needs
to be ground to precision.
Generally higher the rubber hardness more uniform is the
coating

54. Rubber
Roll Web
Gravure
Roll
Ink IN
Ink Out
Coated
Web

56. ReverseApplication
Speed Range: 90-120%
Benefits
Removes Cell Pattern
Film SplitAvoided
Minimizes Ribbing
Adjust Coat Weight with Roll Speed
Rubber
Roll WebCoated
Web
Gravure
Roll
Impression Control is Critical
Light / Controlled Impression
Precision Required – BetterRolls
Driven Impression Roll
Suggested for TensionControl
Overcome ReverseAction

57. WebCoated
Web
Steel
Backup
Roll
 Roll Rotation
 All Roll Same Direction
Synchronous Rotation
 Two Film Splits Thinner Coatings
 Roll Speeds
 All Rolls at 100% Line Speed Single
Drive is Possible
 Gravure Roll is Typically Driven – Idle Mode
 Applicator Roll is Nip Driven Back-up
Roll is Web Driven
3-Roll System
Gravure is Offset from Substrate
Removes Substrate from Coating Nip
Protects Sensitive Substrates
Gravure
Roll
Rubber
Roll

58. • Very Cost Effective
– Coat Both Sides at One Coating
Station
– Single Dryer vs. Dual Dryers
– Reduced Overall Line Length
• Direct Application (Kiss Coating)
– Forward or ReverseApply
– Coat Weight is Susceptible to
Tension Variations
• Limited Range ofApplications
– Thinner Coatings
– Same / Similar Functional
Coatings on Both Sides

63. 5-roll coating system
Extremely slight and precise coating weights are adjustable
Coating weight can be increased or reduced, up to 50%, by
changing one cylinder velocity during machine run
Accurate repeatability through high precision mechanical stops
with micro-adjustments
Specifications
Production speed up to 1500m/min (4900ft/min)
Coating width >3000mm possible
High precision cross profile over the whole web width of 2%
which is guaranteed by using a special cylinder technology witha
patented deflection compensated impression roll
Applications
solvent less coatings with 100% solids
thermal curing
UV curing
EB curing

64. 5-roll coating head for solventless, 100% solids coatings.
The coating head is designed for a production speed of up to 1500
m/min.,
with a coating width of 1700 mm and is equipped with a patented
roll deflection compensating system.
This coating method is especially suitable for low coating weights
with high quality requirements in regard to the coverage and
coating weight tolerances at high production speed.
The precision presetting mechanism ensures highest accuracyin
repeatability of production parameters.

65. • Gravure cum Kiss
coating method for very
low viscosity coatings

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75. Gravure Printing
Some video’s
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Rotogravure printing technology
https://www.youtube.com/watch?v=uv-RkAHuTlQ
Understanding of Gravure Printing Technology
https://www.youtube.com/watch?v=Af4yDdQY_uk
full process of rotogravure cylinder production
https://www.youtube.com/watch?v=5hb3EKQv4ic&t=294s
Graphic Arts; Gravure
https://www.youtube.com/watch?v=xialgxiIpNk

76. Gravure Printing
Some video’s
Don't Miss Out on this Anilox Roll
https://www.youtube.com/watch?v=gL01qR0vVUQ&t=107s
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Prepared by : Md. Ali Hossain.
Collected from: Shrikant Athavale.