M i t s u b i s h i Va r i a b l e - S i z e
Commercial Web Offset Press,
DIAMOND MAX-V, Realizing aDream of the Printing Industry

1. Introduction
Commercial offset presses for printing magazines andadvertising inserts on the market can be roughly classified by the paper conveying method into sheetfed offset
presses using sheet paper already cut and aligned, andprinting on each side or both sides individually, and web
offset presses using a web, printing on both sides continuously, cutting to a specified size, folding and producing
prints. In offset presses, an image plate of thin aluminum plate is wound on a plate cylinder and rotated toprint on the paper. In the sheetfed offset press for holding only the tip of the sheet paper, by selection of the paper
size according to the image size, printing continues without causing loss of paper. In the web offset press, however,since the paper for the portion of circumferential lengthof the plate cylinder is always printed, a printing press
suited to the production size must be prepared in order toFig.1
avoid wasting paper (Fig.1Fig.1).
In web offset presses, since continuous paper is used,high-speed operation is possible and productivity is morethan three times higher than that of sheetfed offset
presses. Printing size flexibility, which is difficult toachieve and for which expectations are high, has long
been a dream of the printing industry. Mitsubishi Heavy
Industries, Ltd. (MHI) has newly developed a variablesize commercial web offset press, DIAMOND MAX-V,
which is easily capable of replacing the plate cylinderand other important parts. A prototype of this press wasexhibited at the print media messe "drupa 2004"(Dusseldorf). Subsequently, a full set machine was operated in public (2005, in Japan), and was highly evaluatedby the printing business both in Japan and abroad.

YUKIKAZU SHOJI* 1

YOSHIAKI KANDA* 1

MIKIO MOTOOKA* 1

TORAO IWAMOTO* 1

ISAMI MITAMURA* 1

HIROSHI KOBARA* 1

Larger margin

Larger margin

Smallermargin

Printing cylinder

Paper flow
direction

Smallermargin

Cut-off lengthWebFig. 1 Relation between machine size and production size
(Top: inappropriate size, bottom: appropriate size)

2. Existing variable-size presses
Although it was not for general commercial printing, there was a business form web offset press capableof exchanging all printing cylinders, but it took a half
day to change the size. The cost of the exchange cylinder is also very high and the machine is not inwidespread use. Around 2000, by contrast, two modelsof an offset press capable of replacing only the outer
periphery of the printing cylinder of the sleeve weresuccessively presented by two manufacturers in Europe
Table 1(T1). However, the applications of these offset
presses are not for commercial printing, and their productivity and quality are not suited to the demand of
the commercial printing field.

Table 1 Comparison of sleeve type web offset presses
Manufacturer

MHI

Model name

MAN Roland (Germany)

Drent Goebel (Holland)

MAX-V

DICO webVSOP 850

Commercial printing

On-demand printing

Form printing

Printed productCommercial printing in general

Small page tabloid

Business form

Printing system

Offset printing on both sides

Offset printing on both sides

Offset printing on one side

48 000 copies/hour

20 000 copies/hour

31 500 copies/hour

Cut-off size

546 - 625 mm

576 - 1 260 mm

381 - 762 mm

Applicable web width625 - 1 030 mm

300 - 520 mm

425 - 850 mm

Category

Productivity

Mitsubishi Heavy Industries, Ltd.
Technical Review Vol. 43 No. 1 (Jan. 2006)*1 Paper & Printing Machinery Division

1To exchange sleeves, the operation side sub-frame
is set aside to the waiting position, an exchange spaceis reserved, the sleeve inner wall is dilated by highpressure air, and the sleeve is then removed and replaced with the desired one. Required time for one
sleeve is about a minute (Fig. 2)2).
(2) Folder
The folder consists of an accelerating transfer belt
device developed and a tip jaw device as a cut-off sizechanging mechanism a folding cylinder and others of
the conventional technology, and the dimensions ofeach size are designed with the maximum cut-off sizeof 625 mm. In the variable size folder, the printingedge and cutting position must be matched, and theprinting cylinder and cutting cylinder of the folder
Fig. 3are synchronized in rotation (Fig.
3). Thus, when thesleeve diameter is changed, the paper speed is changed,
but the cutting timing is unchanged, and the cut-off
length of the paper is always the same as the circumferential length of the printing unit sleeve. If the cut-off
size is smaller than 625 mm, it is controlled so thatthe tip of the paper can be held at the proper time in
the tip jaw device of the folding cylinder.

3. Fundamental technology of DIAMOND MAX-V
The background to development of a variable-size commercial offset press applicable to commercial printing
in general for the first time in the industry is made upof three pillar-technologies of MHI. DIAMOND MAX-V
is the product of a high degree of completion based on
experienced fundamental technology.
(1) Changing technology of printing length: sleeve blanket technology
The sleeve blanket offset press technology using
tubular sleeve blankets that has been employed in
products for a decade is applied in the size changing
mechanism of the printing unit.
(2) Changing technology of cut-off length: shaftless drive
technology
Different speed control technology used in shaftlessdrive commercial offset presses for driving each device by an independent motor is applied in thecircumferential speed adjustment of each drivingroller.
(3) Stable transfer technology of cut-off printed products:
pinless technology
Stable transfer technology of cut-off printed products in pinless folder used for sleeve blanket offset
presses is applied for preventing lags between cut-off
products when accelerating the printed product during change of the cut-off size of the folder.

5. Merits of variable-size commercial web offset presses
The variable-size commercial web offset press realizes the following merits.
(1) Applicable to intermediate size, not limited to A or Bformat
Of the commercial web offset presses presently installed in Japan, JIS B size machines account for 65%(for advertising inserts in newspaper, B5 size magazines, etc.), and JIS A size machines occupy 15% (forA4 size magazines, catalogues, etc.), but printing demands often vary - the A size demand increases or B
size demand increases, or equipment shortage mayoccur. However, the variable-size machine can solvethese problems without installing new machines.

4. Mechanism of change of cut-off size
(1) Printing unit
The printing cylinder has a sleeve mounted on thecylinder main body. By replacement of the sleeve, thecircumferential length of the cylinder and the cut-off
size are changed. The two most popular sizes in Japan, 546 mm and 625 mm, are the minimum andmaximum sizes, and the structure is applicable to any
size between them.

Accelerating transfer belt device

Jaw folding device

Transferbeltdevice

Chopperdevice

Tip jaw device
Second cutting cylinderFirst cutting cylinder
Fig. 3 Variable-size folder

Fig. 2 Sleeve exchange operation

Mitsubishi Heavy Industries, Ltd.
Technical Review Vol. 43 No. 1 (Jan. 2006)2In addition, the production size can be selected
freely, the range of proposals by printing companies
can be extended, and more printing orders can be received. Thus, depending on the proposal of irregularsize books or the required print quality, jobs ofsheetfed press can be also received.
(2) Improved operation rate
A size jobs and B size jobs are reportedly different
in peak season, and presses may be idle dependingon the season. However, by changing the print size
according to the season, the peak and low point ofjobs can be leveled, and the machines can be operated at full capacity throughout the year.
(3) Reduction of paper wastage
In printed matters of different heights such asmagazines, by selecting the cut-off size according tothe production size, paper wastage in binding can beminimized. For example, in recent magazines, the A4
modified size is the most popular, occupying about 40%(B5 size is 35%), and about 95% of the volume is believed to be 285 mm in height. In case of printing theA4 modified size magazines by a conventional commercial offset press, naturally, the A size machine isused. In the binding process, the trimming margin inthis case is more than 24 mm larger per copy thanthe A4 regular format magazine (297 mm in height),
and theoretically paper consumption can be reducedby more than 5%. This saving is impossible with theconventional printing process.

6. Conclusions
The first machine was installed in a printing company in Japan and started commercial operation in late
October 2005. This fact has been taken note of by theprinting industries in Japan and overseas, as it is theworld's first variable-size commercial web offset presswith features superior to conventional commercial
printing presses. Further automated devices and equipment will be developed for the Diamond MAX-V toimprove its value.

Yukikazu Shoji

Yoshiaki Kanda

Mikio Motooka

Torao Iwamoto

Isami Mitamura

Hiroshi Kobara

Mitsubishi Heavy Industries, Ltd.
Technical Review Vol. 43 No. 1 (Jan. 2006)

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