The paper maker and challenges in printing technologies

Per Jonsson, Research Director (Stora Enso Research)

Developing the market share of print on paper as a communication tool in the media market is one of the most important and decisive challenges facing papermakers today. It is a challenge that will to a large extent define the future of our industry. This is not to say that printed paper is at threat or that we are approaching the paperless society. It is to say, however, that with other and competing industries growing faster, we have to struggle for gaining a healthy profit.

Figure 1

Figure 1. Media market development

The above diagram taken from Heidelberg's Handbook of Print Media illustrates the situation well. The print dominance of the media market over electronic media is shifting to a balanced situation meaning a substantially higher growth for the latter.

Our task as papermakers is to provide innovative production techniques and materials to secure print industry profitability. Luckily we are not alone in this battle. We fight it together with our prime customers, the printers. But to realise this in thought and action is another challenge that calls for creation of partnership and alliances.

We promote joint innovative technologies and have done so for many years, secretly on a company basis. We now also need to do this also on the industry and research society level. This mutual understanding of each other's technology was also requested by Patrice Mangin from CTP at the Speciality & Technical papers Europe 2000 Conference in Berlin two years ago. (1)

The S2P2 and T2F programmes

S2P2 and T2F are two Swedish network printing research programmes that currently fulfil these quests. These programmes presently comprise about 30 doctorate students, about 20 completed and ongoing master thesis projects and about 10 senior postdoctoral projects. S2P2 and T2F are jointly funded by the printing and paper industry, together with the Swedish Foundation for Strategic Research and the Knowledge foundation in Sweden.

The network, which also includes some 25 supervisors, is strengthened by steering committees and reference groups . Here researchers and research students regularly meet representatives from both the printing and paper industries.

A sub programme in T2F under the co-ordination of Nils Enlund at KTH is steered to directly explore the strengths and weaknesses of print on paper as a communication tool (2). These results should tell us where to target our development efforts.

Figure 2

Figure 2. The common website for the T2F and S2P2 programmes www.t2f.nu is highly recommended for studies

Behavioural sciences

Another challenge for papermakers is to realise that the customers, who in the end judge our efforts, are individuals, real persons and not other companies. Individuals normally don't buy technologies; they want real products and services. This is an approach and a field where we can learn a lot from partners in the printing industry, who have this situation as their normal daily life and also from the electronic media industry, which since long spend a lot in behavioural research.

One example that we are at least learning a bit of the lesson is last years CEPI-COST Conference in Stockholm under the theme "The future of paper as a Communications Medium". Most of the presentations there focused on the use of behavioural sciences to examine and explain paper in various communication roles. At the end of the conference Cepiprint commissioned STFI to organise a prestudy concerning sociological and behavioural aspects of Printed Media Usage. The pre-study has resulted in a number of cross discipline research proposals. Regardless of their outcome it is safe to say that behavioural sciences have entered the minds of the papermakers.

More evidence of the entrance of the behavioural sciences into the papermaking field can be found in the previously mentioned programmes (2). A close follow up is recommended of the progress of Siv Lindberg's T2F project "Multidimensional analysis of print quality" and of Carl Magnus Fahlcrantz' S2P2 project "Perceptual effects of deterministic noise in digital prints". Both projects represent pioneering work for our industry.

Understanding phenomena behind processes and test methods

Improved understanding of quality and material characteristics is another challenging topic for research and the industrial application of research results. This need has grown parallel with the quality development work on standard grades but is really brought to the edge by the introduction of new printing processes. Mainly this relates to methods and techniques for describing and modelling the interactions between printing surfaces and liquids (including toners) and between printed and printing surfaces and light.

When these new methods are combined with the knowledge gained in human perception preferences we will have powerful tools for product development. For example, they include:

  • looking behind the curtain to see what gloss really is
  • models for light scattering in paper and effects on colour reproduction
  • surface chemistry and topography studies matched with print results
  • characterisation of porosity in printing surfaces and spreading of inks

Digital Printing

Digital printing is probably the new technology development most spoken about in the printing field. Still there are many definitions to choose from when looking behind the concept.

A GAIN reported study by Frank Romano of RIT justifies this talking. Taking Digital Printing into the broadest sense and including copying as well as DI machines, it points at an increase of the digital printing share from today's 1/3 of all paper reproduced to more than 2/3 by the year 2020. A development mainly taking place at the expense of conventional offset printing. (3)

 

Digital Print/Copy

Direct Imaging

Offset Litho

Flexo

Gravure

2000

24%

8%

54%

7%

7%

2010

43%

10%

37%

5%

5%

2020

58%

14%

20%

4%

4%

Table 1 Printing processes

The Print-on-Demand and Book-on-Demand sectors are examples which have developed, thanks to digital printing and mainly techniques of the electrophotographic family. Here a main obstacle to really fulfil the objective of completing the product in one operation lays in the post-treatment of the print.

To supply the market with a paper that performs well in cutting, sorting, folding and binding is a real challenge. We might get some help from the machinery and process development as well as from the toner manufacturers where substantial improvements have taken place recently. A look at the S2P2 project "Optimised folding properties of paper" will reveal the mechanisms involved and also help in meeting the challenge (2).

Many of us were probably positively surprised by the relative robustness of toner digital printing to the type of substrate shown in early test printing. (4) Without reaching the quality standard of offset on coated material about the same fairly good result was achieved with toners regardless of coated or uncoated paper.

It seems, however, that this robustness might be lost with the new developments in toner technology that will reduce the toner layer thickness and make effects of surface finish more pronounced. These effects are addressed in the S2P2 project "Adhesion and friction in electrophotographic processing of papers", where the fundamentals of toner/paper interactions are explored (2).

The higher capacity of the new generations of digital printing presses and statements such as "running unattended for hours" will put emphasis on the runnability properties such as quality consistency and controlled curling.

Inkjet is another digital technology where development is going fast and requiring a quite extensive palette of paper products as substrates. The uses vary from ordinary home computer printing via high productivity variable printing, proofing and glossy photo reproduction to wide format printing for outdoor advertising.

Fundamentally the quality outcome and also productivity of inkjet printers is much connected to the interaction between the ink and the paper. This includes absorption and spreading of complex inks, curing mechanisms as well as physical and chemical models of the surface pore structure of the paper. Also the effects from these processes on the light scattering and colour appearance are vital for the print quality.

Understanding and modelling these phenomena and eventually describing individual perceptions of success and failure are prime tasks for a number of surface science (SS and IPQ) projects in the S2P2 programme (2).

Supplying paper for inkjet has gone from earlier gambling with standard A4 cutsize to the first generation of inkjet printers, a choice that sometimes worked and sometimes didn't, to providing a sophisticated range of surface treated and coated products today.

A big challenge for suppliers of paper is to find a universal paper for both standard offset and digital printing. Firstly, from customer view, quite a number of offset printers complement their equipment with a digital printing press for additional copies or short runs. They would certainly appreciate reduced stockholding and appearance consistency regardless of usage of printing press. Secondly, universal grades should also give possibilities for rationalisation of our own production.

Hybrid Printing Systems

The quest for a universal paper is of course set on its edge for supplying Hybrid Printing Systems, which is another emerging technology for the papermaker to watch. This could involve Offset Flexo, Offset/NIP (Inkjet) as well as Electrophotography/ Inkjet and gives challenges for the papermaker. But again, to find the right path through the quality obstacles suggests a thorough understanding of the phenomena.

Use of Colour

Colour usage is a predominant trend for all printing and it is expected to rise from about 50% today to 80% in 2020 with multicolour as the leading process and the short run end exhibiting the fastest development.

An example of the colour issue from Sydsvenskan, a successful Swedish newspaper, is a 30% increase in colour advertising and a 70% increase in total colour ink purchase over the last three years. Thus editorial sections are increasingly colour printed.

In this context it is also vital for the papermakers to follow the development of waterless offset and particularly the deployment of waterless offset in combination with Computer-to-Press technology. This technique can reproduce sharper and more saturated dots than conventional offset giving improved colour reproduction, better resolution and print contrast (5). Utilising the potential of waterless offset for high-resolution pictures will place high requirements on the paper surface characteristics, both physically and chemically. Jan-Erik Nordstrom's thesis work, "Studies of Waterless Offset" carried out in the T2F programme reveals the fundamentals of the process.

Another result from the increasing use of colour printing is that consistent ICC or other profiles will be required by the printers. Getting acquainted with these techniques both for conventional and for digital printing will be necessary also for the paper suppliers.

Short Runs and Just-in-time deliveries

Printers are presently experiencing a dramatic change in run lengths, partly driven by themselves utilising new technology development for gaining market share but also required by their customers. A GAIN RIT study performed by Frank Romano projects that by 2020 run lengths of 500 and less will account for 30 % of the printing volume. (3)

Developments regarding the Turn-Around-Times are also fierce. Whereas today only around 8% of print jobs are delivered within a day of order the same study predicts this figure to rise to 30% by 2020. (3)

It is evident that these conditions will put increasing demands on the logistics and supply power of the papermaker.

Newspaper

There is a harsh reality for papermakers to realise that printing is no longer the core business of a number of newspapers.

Figure 3

Figure 3. Workflow at Aftonbladet, the biggest newspaper in Sweden

Their focus have shifted from "words on paper" to just "words" and as publishers they look upon themselves as content providers with the printed newspaper as one communication channel among others. An important one though.

It is therefore vital for us to look at the means and measures that are used to promote the printed newspaper. They can be summarised as

ˇ form

ˇ picture

ˇ colour

As papermakers we have to supply a better a product that supports this. One example is controlling the dimensional changes in paper with repeated wetting taking place when all pages in a newspaper are 4-colour. This situation is the background of the licentiate thesis project that Peter Aslund is running within the T2F-programme.

Printers of newspapers also have problems and developments of their own to consider. Runnability with ever shorter delivery times, faster presses and thinner paper is a main question. This is the target for a T2F subprogramme titled "Cost Effective Production" with at least four relevant doctorate projects. Here the fundamental fracture mechanics behind web breakage as well as friction and wrinkling problems are addressed (2). Another headache for the newspaper industry is the distribution costs. Apart from putting pressure on the papermaker for lower basis weights, they also have initiated, in many cases digital printing. The Océ process for Digital Newspaper Networks is already on stream and with that a new set of properties for newsprint suppliers to consider.

Elcorsy or Elcography is a digital technique that has been regarded as promising for quite some years now and still one worth looking out for. The process uses electrocoagulation of ink as a basic principle and is designed for high -speed printing. A test installation is planned for early 2002 and if successful it could well suit distributed printing of newspapers.

Packaging

Today packaging is looked upon as a service provider rather than a product. Protection and logistic services are more or less taken for granted and more emphasis is put on the promotion of the product packed meaning increased importance for the design and print of the package.

Increasing share of flexo has been a general trend for packaging printing during the last decade. Flexo packaging printing in Europe has increased at about twice the pace of packaging print as a whole or by about 8%.

This development has been supported by a number of innovations within the field of flexo printing enabling a considerable leap in print quality. These innovations include:

ˇ digital imaging of photopolymer plates

ˇ FM screening

ˇ advanced plate mounting technology including sleeves

ˇ UV inks

ˇ water-based inks

ˇ new colour management systems

ˇ gearless press drives

Figure 4

Figure 4. European printed packaging market

For papermakers the other side of the coin is a sharp increase in quality demands on material for flexo. Quality specifications are today as critically and strictly defined as for any offset or gravure substrate. But on the other hand that is where the additional shares shall be gained.

Therefore, the days when a flexo substrate was an uncoated and even uncalandered hopefully white, but often brown ordinary kraft with varying characteristics are things of the past. Rather this substrate today is a highly uniform coated material with whiteness, smoothness and ink receptivity optimised for the end use of the package.

It has also been proven that flexo is not the simple process it once was believed to be. On the contrary it comprises complex mechanical and chemical interactions between different materials, liquids as well as solids and semisolids. This has also been noted within the T2F programme where a whole subprogramme with five doctorate students is directed towards exploring the mysteries of flexo (2).

Conclusions

So what then is the common theme for all the areas where we can see new technologies emerging in printing?

For us as papermakers, there is a general challenge. We have to retain our unique knowledge about our own dear processes but at the same time shift our focus to the products they produce or make possible to produce. While doing so we also must recognise that the products in the end are approved and disapproved by individuals.

A second challenge is to co-operate with printers, publishers and packaging providers to gain understanding of the preferences of these individuals and the potential of our joint industries to meet their specifications and demands.

A third challenge is to use this gained knowledge and understanding to put the right questions and requirements in the dialogues with our suppliers of equipment and knowledge.

And fourthly these efforts must be made on every level:
ˇ research as well as marketing and production,
ˇ personal as well as company and industry.

After all we have a common interest of printed paper as a future material and tool for communication.

REFERENCES

1. Mangin, Patriee J. (2000) "Printing technologies, challenges and opportunities... and a significant part of the better paper products equation" Speciality & Technical papers Europe 2000 Conference, Berlin

2. www.t2f.nu

3. www.gain.org

4. DPC, Framkom and STFI, Lars Eidenvall, editor (2001) Digital Printing Evaluation ISSN I650-687

5. O,Rourke, John (1997): The Complete Guide to Waterless Printing, Quantum Resources, Inc

Presented at the 7th International Conference on New Available Technologies, 4-6 June 2002, Stockholm.