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IMPS 2007
16th International Munich Paper Symposium
Progress in Board and Paper Technology
21 - 23 March 2007
R. Beltz, Emco GmbH, Leipzig and
G. Meder, Mohn media Mohndruck GmbH, Gütersloh / Germany
"The most critical paper characteristics for
printability"
Printing at 1904: N e person heads E n printer printing E //i// //i//!
Complexity of printing 100 years ago
"Black art":
Particularly on the activities of the
printer and the typesetter this name is
applied. To the Gautschen
representatives of these professions "
disciple the blacks' art ", may
themselves call "black artist" or
disciple "of Gutenberg".
In a similar connection the concept
"white art" which refers to the skills at
the papermaking exists.
Complexity of printing today
Printing 100 years later:
Printing industry – colour industry – paper industry
machinery manufacturer – printer ...
And who steers what?
Printing
House
Paper mill
Finished product Raw material
Product specification +
established examining norms
Complaint
Research, examination of print problems
Print product
Cooperation Paper manufacturer – printery
What is the interest for the printer ?
However, the classic paper specification is
not decisive for it!
– The paper must run !!! –( Printability, Runability)
Reproducible, sufficient regularity of the material
(paper, ink, glue, ...).
Information about the product behaviour for the
planning, Production preparation, process control
Fundamental properties
Mechanical qualities
Structure qualities
Chemical qualities
Train and rolls qualities
Connection between paper qualities and use requirements with regard to Runability (IFRA report)
Runability
Train demolitions (holes,)
Train stability Young's modulus (
Register)
Walking for the train
Separating ability unpicker for rope
perforation
eveness of this one Expression
Fold formation
Fold break
Properties of the paper
Use requirements
Electrostatics
Further processing safety
Thickness changing
FAN OUT DWs, KWs
+ 5% at 40?(800 E 805) + yields 64 mm+1280 mm
IFRA report Runability
Fundamental properties
Mechanical qualities
Structure qualities
Chemical qualities
Visual qualities
Connection between paper qualities and use qualities with regard to Printability (followed IFRA report)
Printability
Fillers fray Deposits
Colour need
Colour acceptance Water acceptance
Coating Deposits
Colour drying water drying
Gleichmässigkeit of this one
Expression
Pressure sharpness
White-washes or Opacity?
Qualities of the paper Assigned Pressure problems Use requirements
Pulling up
Negative Piling Blinding
Positive Piling Ghosting
Vanishing Dots
Mottling
Cockling
Verb lure
Greasing
IFRA report Printability
Our problem analysis approach
Pressure process gives relevant
properties of every component!
Print press relevant properties of:
• Print press technology / machine
• Colour
• Paper
The paper is object of the refining,
that is reference point for every
pressure process analysis!
Problem analysis prints
What are print
press process
relevant
properties?
Ink
Paper
Print technology
.
Substratum
(Coating)
Base paper
Coloured printing inks
Emulgat Piece of paper water
Compressibility f (P, humidity, fibre type,)
Elasticity, flexibility
Plastizität/Deformierbarkeit
Z strength
Humidity
Grammatur, volume
2-Seitigkeit
Topography
Surface energy
Kapillarität/pore volume distribution
absolute pore volume
Roughness/topography
Area of the pressure point
Composition f (time)
Viscosity/Tack/G ', G; Dehnvisko
Emulsion quality (droplet size)
Surface tension
Entmischneigung/Entmischkinetik
colloidal stability
Emulsifying inclination DF/WW/kinetics
Way blow behaviour
Rubber cloth
Composition f (time)
Viscosity
Surface tension f (t)
Pressure
Time
Surface energy
Roughness/topography
Material type
Side/hardness
Process conditions:
Contact time on rollers
Temperature/atmospheric humidity
geometric order
Discount behaviour/angle
Effects in the Nip
Influence matrix printing
Complex interplay of all parameters or there are A-factors for printing relevant parameter?
~ 15 m
Grid-Point
~ 100 µ m
5 mm Pressure Nip
2 m 2 m 2 m
5 mm?~ 10 sec
100 µ m?10 -10 sec
-4
-5
Dryer/KWS
~ 19 m
Superstructure/fold
10 m/s
V =?10 m/s 0.2 sec 0.2 sec 0.2 sec 1.5 sec 2 sec ~ 4 sec?
V = 15 m/s 0.13 sec 0.13 sec . 0.13 sec 1 sec 1.3 sec ~ 2.6 sec?
Damp water must having disappeared in the paper surface, next before paper Reached Nip place has!
> 1 sec Dwell time in the dryer
Example: Grid distance 70 Lpc, 40% global coverage Matrix dot diameter: 102 µ m yields
Time conditions in the printing press
-6
RW
Web offset
10-4 10-3 10-2 10-1 100 101 102 103 104 105 106 107
lg t
Short time Middle time
1 sec 1 min. 1 H
Long time
~ 1 day 11 days
Matrix dot moving the Nip
Capillary transport V. Liquid into pores
Steam diffusion into pores
VD
U = 620 mm
V = 15 m/s
Matrix dot: 100 mm
Nip = 5 mm
Publication distance = 2 m
Paper length DW 1 fold = 40 m
Water shipment to the fibres
Trapping matrix dot meets the next Ink
Pressure point deserts publications 1-4
Drying
Fold
PRACTISE
Bar forklift Palettierer
Store
Dublieren
Drying problems
Abschmier-problems
Cockling
sec
G
NP
PP
Mottling
Greases
Verb curls, stick of products
Smell formation
Temporal classification of the pressure problems
?
Visual densities for coloured printing inks with a different colour layer thickness
1 MT colour layer thickness:
Black D = 1.8
Cyan D = 1.5
D = 1.4 magenta
Yellow D = 1.3
Standard (paper class 2):
Black D = 1.75
Cyan D = 1.45
D = 1.4 magenta
Yellow D = 1.25
(Kipphan, manual of the print
media)
s
Dependence of the matrix dot diameter R of density step x and grid distance RW
2 R
FR
LRW
RW = (grid value z.B 60s grids, RW = 60)
LRW = grid distance
TW = density step = (e.g. 40% density step x = 40)
40% density step meant:
100
x
2
RWR L100
40F
2
22
RW
2
RRW
10
100
xL
100
xRF
x
RWR
1
30
40
50
60
70
80
90
100
45 50 55 60 65 70 75 80 85
RW
R [μm]
x = 20
40
60
Size conditions in the pressure
5
50
5
1 µm water layer or colour layer
Coating
60 g/m2
Paper
60 µm
Water, colour layer
+2 µm
5 µm
15 µm
1 µm
Z
Z
Coloured micrograph of
paper fibres
A scanning electron
micrograph of fluid
inside The partially
saturated zone of paper.
It shows The pore ares
unfilled and that fluid is
moving through film
flow, need The paper
primarily ace via The
bulk filling of pore (ace
hectare traditionally
been thought to be, The
Case).
credit: photo by Ray
Roberts
Where the colour is, where the water?
Absorption dynamics into coated paper (Schölkopf, Gane, The moment ink contacts of The surface..)
The dynamic absorption behaviour of Fluiden to a porous medium determines this one
printability of painted papers in the context of the way blow behaviour.
Parameters are pore structure, size distribution the pores: (preferred pathway river)
capillarity and permeability.
The balance between Spreitung,
penetration/absorption influences the process
Surface energy of the phases involved (celebration
liquid, gaseous) determines contact angles and with
that the wetting
A geometric order of the different interfaces checks
the motion of the gas/liquid interface meniscus ()
Surface roughness has influence
External pressure
Chemical inequality
Contact paper/top-hat, Dwell time t (L1)
Verweilzeit der Rasterpunkte im Gebiet L1
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
10 15 20 25 30 35 40 45 50
Ex/h in tsd
t (m
s)
FO43 FO23 FO39 FO 25 / 26 FO 37 / 38 FO 40 / 41 FO 33 FO 27 / 29 / 31 FO 36 FO 35 FO 21
FO 43
FO 23
FO 25 / 26 / 37 / 38 / 39 / 40 / 41
FO 27 / 29 / 31
FO 33
FO 35 / 36
FO 21
w1
L1
w3
w2
L2
L3
Example pressure problem Vanishing Dot
109' 110' 111' 112' 113' 114' 115' 118' 119' 120' 121' 122' 123' 124' 125' 126' 127' 128' 129'
DV 1,82 1,51 1,61 1,65 1,67 1,65 1,67 1,6 1,62 1,68 1,71 1,71 1,69 1,75 1,75 1,81 1,8
80%
40% 15 23 22 20 19 17 16 22 18 17 19 17 16 15 16 16 15
DV 1,4 1,3 1,37 1,39 1,4 1,36 1,38 1,31 1,35 1,37 1,37 1,43 1,43 1,42 1,4 1,41 1,4
80%
40% 16 24 24 22 20 18 18 23 20 19 18 18 17 17 17 19 16
DV 1,62 1,64 1,65 1,63 1,64 1,66 1,65 1,65 1,63 1,61 1,61 1,63 1,63 1,65 1,64 1,65 1,66 1,65
80%
40% 17 23 24 22 22 20 19 24 25 22 21 19 19 18 17 17 17 16
DV 1,74 1,7 1,74 1,73 1,75 1,72 1,75 1,68 1,69 1,68 1,7 1,71 1,72 1,72 1,7 1,72 1,72 1,72
80%
40% 25 25 24 23 25 25 24 25 25 25 24 24 23 24 22 24 24 22
10
12
14
16
18
20
22
24
26
DV
/ T
WZ
Test II - FO29 unteres DW
Process
Train speed
Train tension
Farb, water leadership
Temp., dampness
Subject (front U . back)
Paper
Type, line
Grammatur
Resistances
Sucking ability, porosity, Perm.
Seitigkeit
pH
Colour (pigment, binder, additives)
Viscosity, toughness
Water photo
Fluctuation into consistency
Colour additions (paste, thinner, ..)
Water, damp means
Surface tension
pH
Elektr . conductivity
Harden etc.
Temp.
Rotation
Top-hat order
Top-hat diameter
Separating acceleration
Farb, damp plant
Roller cover
Plate
Negative/positive
Grid
Preservative
Water photo
Rubber cloth
Type
Topography
Compressibility
Spring resistance
Quick release
Example pressure problem Vanishing Dot, Ghosting
Paper specification and printing phenomena
There is no simple correlation between a pressure problem on the one
hand and an effect or a parameter of the paper specification on the other
hand.
It is important to analyse the different printing problems and phenomena
for the printer lead her to different working mechanisms.
It is important to know the potential for a printing problem (e.g. Ghosting,
verb curls etc.). It depends on different factors and conditions, whether and
as the printing problem also really appears strongly.
"The journey is the reward.“
Topography
Young's modulus (dampness)
strength
Behaviour with water, oil
(capillarity, sucking ability)
Tack measuring
Identification values
paper, standard
(thickness, V,
type,)
?
Colour
consumption
Train thriller
Pressure
problems
Printability
Runability
Print quality
Our problem analysis approach
Pressure process gives relevant
properties of every component!
Print process relevant properties of:
• Print technology / machine
• Ink
• Paper
The paper is object of the
production, the paper has to be
in the focus for every print
process analysis!
Problem analysis printing
What are print
process
relevant
properties?
The nature of a paper
1. Surface topography
2. Compressibility/strength
3. Capillarity
4. Water absorbency (surface tension of the fibre wall)
5. Dimension (thickness, length MD, breadth of CD)
6. Modulus of elasticity (E-Modul)
7. Grammage and stiffness as a function of the water content.
The hidden properties of the paper
Paper fibres are hygroscopic, i.e. they react in the environment to humidity, temperature
and therefore also to air pressure until a balance state adapts. These events are
dynamically and directly connected to a change of physical qualities of the fibres and
the fibre structure.
The nature of the paper determines its process properties !
The major properties of the paper for the print press process are:
1. Topography (ink assignment, amount of ink, colour impression, colourconstruction)
2. Compressibility in the print gap (ink assignment, ink stand)
3. Capillarity (ink absorbency, ink anchorage, ink drying, ink stand)
4. Water absorbency (surface tension of the paper and the fibre wall)
5. Dimension stability and strength (opposite water and temperature)
6. Elasticity and its change in dampness and heat (E-Modul)
7. Absolute water content condition of the paper (balance dampness).
The properties 1-6 are dependent on the water content of the paper!
Process properties of printing papers to Beltz and Meder
One can measure all important printing process relevant properties
and one get numerically values for each property !
Process property Topography
1st property: topography
2nd measuring principle: direct measuring of the property
Stripe light projection determines millions some height information with an evaluable
resolution of 0.1 µm in the point grid 1600 x 1200 (1,92 ) to an area within 6 seconds.
Sensors are used for printing papers by 100 mm² or 400 mm² with measuring areas.
3rd measurement result parameterCalculating out judging algorithms which are mathematically dominated and motivated:roughness measure and values according to DIN EN ISO 4488 and 4487, roughness in ± µm
surface volume in cm3/m2
scaredness index according to Dr. Praast
Kriti's heights and depths with number and area, decision value in µm eligible for office.
4th significance for the printing process
Ink assignment, ink consumption, colour impression, stood liability, colour construction
Comparison of the topography before and after the pressure uncovers the effect of the
printing process for the topography, e.g. offset Heatset, decoration pressure.
Print phenomena: Mottling, Missing Dots, barns.
Process propertyCompressibility
1st quality: compressibility
2nd measuring principle: indirect measuring of the property
Stripe light projection determines millions some height information with an evaluable
resolution of 0.1 µ m in the point grid 1600 x 1200 (1,92 ) to a line area within 6 seconds.
The paper is pressed at the measuring with a line pressure corresponding to the printing
process against a visually transparent plate.
3rd measurement result parameters to one defined pressure
calculating out judging algorithms which are mathematically dominated and motivated:
roughness measure and values according to DIN EN ISO 4488 and 4487. roughness ± µm
surface volume in cm³/m2
scaredness index according to Dr. Praast
Kriti's heights and depths with number and area, decision value in µm eligible for office.
4th significance for the pressure process
Ink assignment, ink consumption, colour impression, ink stand, ink construction
Compare it with and without under pressure repetitions and dampness steps is possible
for topography provide information about the process understanding
Print phenomenon: Mottling, Missing Dots, Ghosting.
Process propertyCapillarity
1st property: Capillarity
2nd measuring principle: indirect measuring of the property
Ultrasound transmission measuring emcoDPM after dynamic contact of a paper
page with n-Heptan.
3rd measurement result parameter emco7 (tD) from page 1 and emco7 (tD) from page 2 in the print process relevant time
duration D.
4th significance for the printing process
Ink absorbency
Ink drying
Ink anchorage
Ink construction
Colour impression, pressure gleam, colour intensity
Print speed area
Sideness (differences between side 1 and side 2)
Print phenomena: verb curls, stick together, Dublieren, Ghosting, grease, put down
board like stiffening.
Process property Water absorbency
1st property: Water absorbency
2nd measuring principle: indirect regulation of the quality
Ultrasound transmission measuring emcoDPM after dynamic contact of a paper
page with distilled water.
3rd measurement result parameter
emco1 (tD) to of emco7 (tD) from page 1 and from page 2 in the pressure process
relevant time domain D.
Measuring is also possible with damp means and other liquids.
4th significance for the pressure process
Dynamics of the damp middle photo
Print speed area
Seitigkeit (differences between page 1 and page 2)
Water sensitiveness of the surface
Whether capillary penetration or fibre absorption conclusions about this are
Pressure phenomena: greasing, put down, Dublieren, verb curls, stick together.
Process property Dimension stability
2nd measuring principle: direct measuring of the property
Dynamic measuring of the length change into CD and MD under water or humidity
influence and drying. The change of the water content in the fibres lets itself be seen by
expansion and shrinking. There are two different measuring principles which measure the
change by load cell or optical by image analysing.
3rd measurement result parameterDimension change in %
extended over a time domain which establishes the change. Time domain (milliseconds) is
possible and required the dissolution on a print process relevant.
4th significance for the pressure process and the further processing
Wrinkle,
Fan out potential,
Flatness, waviness in multilayer products, waviness in the printed area,
Long time stability of print products,
Loss of gloss,
grow over of edges.
1st property: dimension change at wetting and drying
Process property Dampness dependent modulus of elasticity
1st property: dampness dependent modulus of elasticity
2nd measuring principle: indirect regulation according to the method of Beltz & bellringer
Under defined dampness conditions the Young's moduli are determined. With a second
method the dynamics of the dampness photo of the paper is determined.
3rd measurement result parameter
4th significance for the pressure process
Provision of the specification values for Bahnspannungs, colour register and cut
register regulations. These can do one fully automatic on the paper and its dampness
condition secure abgstimmte process control.
Dynamischer E-Modul-Verlauf
50
75
100
125
150
175
200
225
250
275
300
325
350
375
400
0 0,2 0,4 0,6 0,8 1 1,2 1,4 1,6 1,8 2
Einwirkzeit [s]
Bahn
span
nung
[daN
/m]
Papier B
Papier C
Papier APapier D
emco Methode
Process property Water content dependent paper condition
1st property: water content at balance dampness
2nd measuring principles and method: indirect regulation with a method.
Regulation of the environment climate of the paper, at least the temperature and the
relative humidity of the air.
Determination of the water content in the paper automates with a NIR method or with a
hand-held test equipment "emcoDelphin". A measuring judging comparison in a time
domain shows, whether the paper is to the environment in the balance.
3rd measurement result parameter
temperature of the surrounding air in ° degrees Celsius
relative dampness of the surrounding air in % rH
weight per cent water in the paper with a reproducibility of 0.1%
whether the paper was yes no statement about this in the balance.
4th significance for the pressure process
Condition determination of the paper,
Transferability and interpolation of the parameters of the paper specification (this is
only valid for a norm climate) on the current climate in the pressure hall,
Supervision of dewpoint and critical climate conditions.
Knowledge of the print process relevant
properties of paper (numerically):
1st choice (purchase) of the suitable paper
The paper is in the focus!
2nd arrangement (order, machine, ink, paper)
3rd consideration in the prepress (plate)
4th fine tuning of the ink (future)
5th machine presetting (regulation ranges)
at consideration of the climate
What is won for printer?
6th cause analysis in the problematic case and knowledge profit at every phenomenon!
Quality management+efficiency
Database
all material and
process relevant data
of a paper and his
NIR reference spectrum
The measurement concept connects
Paper Lab
+ database
Material data for
converting processing
and process control
NIR terminal
Paper
reconnaissance
and assessment
of the condition Paper Lab
laboratory
Online measuring
(Safeguard the regularity)
PAPER
MANUFACTURER PAPER
CONVERTER
DOMAS modules Topography
Roughness
Surface-Volume
Scaredness
Structures etc.
Paper identification
Contents substances
quantitative
Water content
NIR
3D SLP
Scanner
www.database-paper.virtuell
NIR terminal emcoPPA Print
Integrated double climate measuring (temperature and humidity) in the room and at the paper
Cooperation between partners – manufacturer and printers !