The market share of digital printing, which is based mostly on toner technology, is expected to increase from the current level of 5% to around 25% by 2010. Digital printing will enable information produced anywhere in the world to be printed locally on pre-printed or unprinted paper. The effectiveness of publications is dependent on their print quality. Toner print quality is linked to the transfer of toner from the printing machine to the paper, toner adhesion to the paper, the paper itself, and the effect of the paper surface on the toner. Test methods will be developed to evaluate toner transfer, toner adhesion and toner print quality. The most effective use of paper surfaces will be made to reach the targeted print quality. Pre-printing flexo water-based ink and UV offset ink, leading to non-solvent evaporation, will be developed and the surface treatments of paper will be optimised. The parameters of toner printing machines will be enhanced, as will the properties of the toner. Print conditions will be defined for eco- and environment-friendly, high-quality and low-cost printing.
The project aims to define the requirements for safe, high-quality printing in high-speed and performance laser printing devices, using mono-colour or multi-colour dry toners. This also includes requirements for converting devices like folding and binding machinery.
The initial aim of the project is to develop a fundamental knowledge of printing technology, including toner transfer and paper adhesion, printing quality and the conversion of printed paper.
The influence of different parameters will be investigated: the effect of paper (surface energy, roughness, permeability), toner (composition, glass temperature, rheology), and printing conditions (temperature, pressure, dwell time), on toner transfer and adhesion. Printing quality and the converting ability of printed papers will also be investigated.
The work will lead to the optimisation of different parameters of toner-printing technology (paper, toner and printing processes) to guarantee efficient toner printing in terms of transfer, adhesion, print quality and conversion.
Progress to Date
The project comprises seven different work packages.
Work Package 1. 'Mapping' involves the comprehensive assessment of the current situation in modern high-performance printing systems, and the paper and toners available for these systems. Three technical reports have been written and the work package has been completed.
Work Package 2. 'Tools for transfer and adhesion assessment' involves developing and validating test methods for quantifying toner transfer and toner adhesion to paper. Two technical reports, including testing protocols, have been written and the work package has been completed.
Work Package 3. 'Tools for printed paper quality assessment' entails developing test methods to evaluate visual print quality, the environmental impact of laser printing, and to define the requirements for converting printed paper to different systems. Two technical reports have been written and the work package has been completed.
Work Package 4. 'Paper investigation' studies the influence of paper properties on toner print quality. Different types of papers (uncoated, coated and pre-printed) have been produced and printed with toners on an industrial scale. This work package has been concluded.
Work Package 5. 'Machine investigation' entails studying and optimising the printers, and converting machinery to produce high-quality printed products. Many trials have been carried out with different types of papers and toners, and different configurations of the converting line. A report has been written and the work package concluded.
Work Package 6. 'Optimisation of parameters' consists of studying the respective influence of all parameters studied to determine optimal conditions for toner printing and conversion. Three reports have been written and the work package has been concluded.
Work Package 7. 'Solutions for improved products' consists of defining recommendations for future developments and new technical solutions. This work package is continuing.
The planned schedule has been maintained. However, the last meeting and the development of the final report required a six-month extension of the project due to temporary staff reduction.
The results are summarised in the final report of the project.
The exhaustive mapping of the toner-printing technology is presented, as well as the properties of the papers, toners and pre-printing inks.
Various relevant tools are proposed and optimised to measure toner transfer, toner adhesion and print quality, through visual examination or automated image analysis.
The correlations between paper properties and toner print quality have been investigated and recommendations to produce papers with good 'runability', toner adhesion and printing aspects are given, as well as recommendations concerning printing and converting machines.
Scientist responsible for the project
Ms VERONIQUE MORIN
Domaine Universitaire Box 251
38044 Grenoble CEDEX 09
France - FR
Phone: +33 4 76 15 40 36
Fax: +33 4 76 15 40 16