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Automation of newspaper printing machines: visit at CIEL

Prof. Dr. H. KirrmannABB Research Center, Baden, Switzerland

2006 April, HK, 1/36

2 CIEL visit - Printing principlesEPFL - Industrial Automation

Offset printing

The most common form of printing low and high-volume jobs used today is "offset" - used for everything from fliers to magazines and newspapers.

Offset printing uses an intermediate medium between the printing plate and the paper - the rubber-coated "blanket" is inked by the plate roller under relatively low pressure, to prevent the image from deforming. Half a revolution later the same image is printed on sheet or continuous (web) paper under much higher pressures. The plate is continually inked to maintain the image on the blanket.

Printing plates don't have any "relief" - there is no change in depth where the image isn't printed - instead the plate uses Teflon to repel water from some areas.

http://www.umax.co.uk/support/binuscan/technotes/nbi03.htm


Offset plates

The printing plate is initially coated with a light-sensitive material that protects the water-repellent Teflon layer below - this top layer retains water, preventing ink from building up and being printed on the blanket.

In areas where the Teflon has been revealed water will not stay on the surface of the plate, but ink will - hence the exposed areas are those that 'print'. The coating of the plate is removed using a photographic process and (typically) a negative copy of the image-setter films.

To produce the plate, films are held in place over the coating (usually via a vacuum frame to ensure perfect contact) while areas of the plate are exposed by a high-intensity UV light source. The plate is then chemically processed to expose the Teflon and fix the coating.


Halftones - Dot Shape, Screen Ruling and Screen Angles

To give the illusion of a continuous tone image when printed, all images have to be recreated using "halftone" patterns of regularly spaced ink dots, of varying sizes.

To "fool" the eye into seeing a continuous tone image, the lines of dots are very close together: typical line screen rulings are 133 lpi for mono (sometimes 120 lpi) or 150 lpi for colour (or higher). Although these general values are valid for "conventional" printing, uncoated stocks and especially newsprint dramatically reduce the line screens used (e.g. 100 lpi mono / 120 lpi colour).

The size of these dots, measured in a percentage tint, represents the lightness/darkness of each small area of the image.

The spacing of the dots is the "screen ruling", normally measured in Lines per Inch (lpi).


Colour printing

Colours are reproduced by combining four inks: (CMYK)Cyan, Magenta, Yellow, blacK

web lead

plate cylinder printing cylinder

A page printed in full colour must therefore pass through four cylinders, in the order CMYK.

bande de papierPapierband


Moiré and rastering

Overlaying several halftones produces interference patterns, called "moiré".

The most effective dot shape in 4-colour printing is elliptical - this allows overlaid colours to be "angled" to minimise interference.

The angle between Cyan and Magenta is critical as interference is obvious;

Yellow is far less critical as the colour is so light against white paper;

Black will give interference effects but is usually only reinforcing dark areas of an image where moiré is obscured.

The screen ruling (measured in lines per inch) varies between colours to reduce “rosette” patterns - the four "irrational screening" angles will usually average the output LPI, with black typically the highest ruling, angled at 45º.


Computer-to-Plate

In Computer-To-Plate (CTP), there are no films anymore: the plates are directly etched by a powerful laser and treated chemically.

The plate precision is in the order of 0.05 mm, so that the different colours blend without visible shadows.

The next step will be Computer-to-Cylinder: there will be no more plates, the cylinders will be directly written by a laser (and erased for the next production). However, this technology is not yet mature and the number of copies produced in one run (before rewriting the cylinder) is insufficient for a newspaper production.


plate

Around a cylinder

waterfaucets

homogenizer

ink supply

rubber cylinder(blanket) ink

water


Two cylinders

plate

rubberblanket

rubber blanket

plate


Cylinder arrangements

each manufacturer has its preferred cylinder arrangement


Tower and Folder

web

folder

turner bar

draw roller

folder roller

upper H

lower H

reelstand

dancer roller

infed

tour d'impression

barres de retournement

entonnoir

bobines

cylindres

plieuse

bande

12 dN/m

20 dN/m

25 dN/m

trotteuse

débiteur

tensionvalue


The folder

The folder folds one or several webs into bundles ("cahiers").(picture taken while introducing the paper in the machine)


10 75

14

10

3

7

Simple and Double production

16

12

1

5

14

10

3

7

16

12

1

5

12

8

6

1

3

5 68 1

8

6

1

3

5 68 1

double productiontwo newspapers per rotation of the cylinder – the same plates are mounted twice on the cylinder.

simple productionone newspaper per rotation of the cylinder – all plates of a cylinder are different

cylinder(flattened)

31416 1

11 1111


Web path

web

web colours

couleurs des bandesturner bar

barres de retournement

reelstands, changeurs de bobines

bars

folder

plieuse

web width

largeur de la bande


Paper colour and cylinder arrangement

Every newspaper is different. The web path is switched after each productionand the paper is thread in by a carrier system.


Web tracks (Chemins de papier)

Nearly every production requires a different threading


The transporter

The transporter carries the printed newspapersto the expedition.

En route, insets (advertising, prefabricated parts) can beinserted.


Drives

The cylinders were formerly connected by a shaft (Axe, Welle). Today, the shaft is replaced by an electronic synchronization based on a hard real-time bus, SERCOS.The precision of the drives position is about 0.05 mm, i.e. 2.5 microseconds at 20 m/s web speed.


Section control

A section is a number of towers producing into exactly one folder(towers can be assigned to different folders depending on the number of pages).


Several sections (folders)


Example WIFAG machine

Terminal Server

Bridge

Remote Diagnosis

Modem

Ethernet

Report Printer DB Server and

Workplace

MPS Production Computer 760

DECPersonal Workstation

Backup DB Server andWorkplace

Ethernet

CC

PM

Linebus AF100 RC

THE DALLAS MORNING NEWS

ArcNet

Sectionbus AF100/1

T3 T6

F TS

F1 T8 T10T4 T9

R2RSR1 R8R6R4R3 R5 R7 R9 R10

L

RIP Interface to Parascan

Report Printer

MPS Inform 710(Option)

PC

L U

R11

L U

T1 T2 T5 T7

SL U L UL L UL U

Sectionbus AF100/2

RC

L U L U T

RS RS RS RS RS RS RS RS RS RS

CC CC CC CC

PM

PM PMBackup

EP

Key of Symbols

L Lower H-Unit Control (AC110)

Mounted in Bridge

U Upper H-Unit Control (AC110)

Mounted in Bridge

T Turner Bar Unit Control (AC110)

Mounted on Press

S Section Unit Control (AC110)

Mounted in Cubicle SK

F Folder (Double) Unit Control (AC110)

Mounted on Press

G

G General Fct Unit Control (AC110)

Mounted in Cubicle NK

RC Reelstand Coupler (CS31)

Mounted in Cubicle SK

RS Reelstand Control System (WPOS)

Mounted on Reelstand

PM PressMaster System

Mounted in Cubicle PMR

CC MPS Control Console (LS)

EP Event & Fault Printer

PD

PD MPS Prod. Computer Distribution

Integrated in Cubicle MRV

U2U1


The console

The console allows to:

load the machine configuration

save the settings

adjust the ink and water for each page

display the state of the machine

display alarms and events

support diagnostics

save the settings

Console = Leitstand, pupitre


Console: adjusting the colour for each lane (screw)

a page is divided into lanes, each each controlled by a "screw“ that adjusts the ink and water

("vis d'encrage“Farbschraube)

in the console at right, 11 lanes are visible


Console: adjusting the web tension

the web tension defines the print quality, it varies as the machine warms up and humidity changes, but shall not lead to paper tear.


Console: Alarms

there are some 1000 different alarms, categorized by severity.

Alarms must be acknowledged.


Console: On-line help

By clicking on ? a help text

corresponding to theactual windows is

displayed with Acrobat


Control Structure of an H

IOIBS safety bus

loop

IBS-M

BA DIO MCU LBA

BA AIO MCU LBA

DisplayLocal bus

IBS-M

IO IO IO

SERCOS-drive

IOloop IO IO IO

functions:

local display, local command buttons, supervision of paper tear, color screws, water

Work controller

check controller

IBS long-distance bus

Turmbus


Networking a printing machine section

Falz- und Wendeturm-

steuerung

to production preparation(Ethernet) bridge

PMPMstandby

GW GWstandby

Section bus D

Line bus - AF100 Rollenwechsler- koppler A

Pressmasterbus (Ethernet)

Interbus-S

PECOM-ARCnet

Rollen- wechslerkoppler I Sektions-

steuerungMR93KT94

IBG

V-Sercos

IBG

Interbus

AC160 AC160

H -PLCs

Service-ARCnet

Turmsteuerung

Section bus BSection bus C

H-Sercos

IBG

V-Sercos

IBG

Interbus

AC160Turmsteuerung

IBG

V-Sercos

IBG

Interbus

AC160Turmsteuerung

IBG

KT94

KT94

KT94

KT94

KT94

KT94

KT94

KT94

KT94

KT94

KT94

KT94

KT94

KT94

ODC

KT94

Oxydry-Arcnet

Oxydry

Sektions-

steuerungAC160

Auro

Tower-ARCnet

LS LS LS

V-Sercos

Section bus C (AF100)

Interbus-S 4G

Towers

Reelstands


Multiple sections

Section Control

MPS Control Console

reelstand control

B C DE

SS3 SS4

MPS Production

OP1 Oxydry (washing)

Reelstands

SS5SS2

PMLSLSLSPMLSLSLSPMLSLSLSPMLSLSLS

MPS

tower and foldercontrol


MPSproduction

consoles

Speed and hierarchyresponse time

section control

tower/foldercontrol

Ethernet

Arcnet

tower/foldercontrol

tower/foldercontrol

section control

SERCOS

Interbus-S

AF100

Messages

Process variables

motors

cylindres


Organisation of newspaper production


Production Order

O r d e r D a ta

T ite l

D a te O f Is s u e

O rd e r N u m b e r

O rd e r V a r ia n t

Pr in t R u n 7 2 0 0 0 7 2 0 0 0 7 2 0 0 0 7 2 0 0 0G r a m m a g e 4 5 4 5 4 5 4 2 .5V o lu m e 6 8 1 4 1 6 4 8S e c t io n S tr u c tu r e B 1 8 /T 1 6 /B 1 8 /T 1 6 B 8 /B 6 B 8 /B 8 T 4 8Pa g e s + S p o t 0 2 0Pa g e s + 1 c 0 0 0 8Pa g e s + 2 c 4 0 0Pa g e s 4 c 8 2 8 1 6In s e r ts O m e g a B M W N ike

G N C" Pa g e s " Pla n n e d ( D - 1 ) 2 3 :0 5 :0 0 ( D - 1 ) 2 1 :3 0 :0 0 ( D - 1 ) 2 0 :1 5 :0 0 ( D - 2 ) 1 0 :4 5 :0 0D e liv e r y Pla n n e d ( D ) 0 4 :1 5 :0 0

0 8 -0 2 -0 0

M o rn in g S ta r K 0 0 5

1

E d it io n V e rs io n sE d it io n 43 4o f

P ro d u c t D a ta

3 W e s t

C o s ts


Roll logistics


Prepress and Workflow with MPS Cockpit


WIFAG

Based in Bern, worldwide number 3

WIFAG and ABB pioneered the shaftless press, which is standard today.

industrial automation automation industrielle industrielle automation automation of newspaper...

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