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Large Scale High Speed Newspaper Offset
Masakazu Akatsuka, Mitsubishi Heavy Industries,ltd., Toshio Yoshikawa,
Mitsubishi Heavy Industries,ltd., Satoshi Matsushima, Mitsubishi Heavy
Industries,ltd., Koji Nishiyama, Mitsubishi Heavy Industries,ltd., and
Shoichi Aoki, Mitsubishi Heavy Industries,ltd.
1. Abstract
We developed newspaper offset press with high
productivity, high print quality, and high reliability to meet the
expectation from newspaper industry that needs to print high quality
newspaper in tight time schedule. (Fig.1)
This press introduced as gDiamond
Starh has capability to run at world fastest 90,000 copies for an hour,
which enables three sets of Diamond Star presses to complete jobs that
needed four sets of conventional speed presses before.
Diamond Star
presses also reduced energy consumption by 20% comparing to our old
presses.
Variety of fundamental research projects had been done to
insure high quality and high productivity simultaneously; structure and
vibration analysis, handling of thin paper, stable transfer and supply of
ink film in the order of micrometer, to name a few.
2. Technology
Newspaper offset press shown in Fig.2. (height 15m, length 20m)
prints 40 pages of newspaper including 16 full color pages. Main
components of the press are reel stands that hold paper rolls, infeed
units which control paper tension before printing process, printing units,
web path section that arranges page sequence, folder that cuts and folds
paper web to produce final newspaper, and control system.
Reel stand and infeed unit
For the stable operation at high speed
where 1.2 tons of newsprint roll is consumed in 20 minutes, precise
tension control system and automated splicing devices are designed, which
reduced paper breaks during print operation.
Printing unit
Color images are reproduced after four separate color
printing. Each color must be printed exactly on the same position,
otherwise images become blurred. In order to align four color images
within some ten micrometer while allowing paper to run at 14m/s, rigid
frame and improved roller design for less vibration are applied. Improved
ink roller design, based on the research works of emulsified ink transfer
at roller nips, also give uniform and vivid print image.
Web path
Paper tension analysis and the simulation technology
developed better design method of arrangement of rollers and air floating
devices, which enables stable and accurate paper handling at high
speed.
Folder
Printed paper webs are gathered, cut, and folded at folder
where unconstrained paper edges moves irregularly, which tend to cause
paper wrinkle and breaks. High speed visualization technology and computer
simulation helped us to apply specially designed folding rollers and air
jet to reduce paper deformation in the narrow path.
Environmental improvement
Reduction of mechanical losses such as
friction, use of fully independently controlled distributed motor drive
system and relating technology contributes to energy saving. Stable paper
handling and precise ink supply system reduced paper waste from newspaper
printing plant that consumes a lot of paper.
3. Conclusion
The first Diamond Star press starts printing from
April 2004 ( start production at May 2004). Five sets are in the
operation, two are under installation, and five more sets are ordered,
which indicate the Diamond Star press is welcomed from the newspaper
industry. (as of September 2004)
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