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

Matrix dot diameter

Grid diameters: 119 84 60 42/1000 mm

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

Where is the colour?

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

Example printing problem „Ghosting“

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 !