Quick Start Print System ofCommercial Offset Press
SHIGEO MAKINO*1
MASAKAZU AKATSUKA* 1
TATSUO FUJIKAWA*2
SHINICHIRO SENOO* 2
HIROSHI KOBARA*2

Most of the printed matters including folded leaflets of newspapers, catalog magazines and books displayed in thebookstore shelves are mass-produced using commercial offset presses with printing capacity of approximately 50 000
copies per hour, with the amount of paper consumed being huge. About 10% of the consumed paper is laid on the
shelf (as waste) because of the difference in the color of the sample, which mostly occurs during the printing start
time, i.e., in the quasi-printing stage. The “Quick Start Print System of Commercial Offset Press” is equipped with asystem capable of reducing the said time zone by half, contributing to the saving of resources and improvement inproductivity.
In the case of color printing normally 4 colors (black,indigo blue, red and yellow) are mixed to provide different color tones, with the color tone of the transferred
pictures, printing positions of the 4 colors (register), cutting position and folding accuracy counted as the factors
most influencing the printing quality. These factors delicately react to the changes in printing speed and tension
at the time of paper traveling depending on the qualityof the paper, and cause difference between the printed
paper and the proof sheet, resulting in generation ofwaste paper that cannot be counted as a product. Various adjustments of the aforesaid color tones are carriedout during the time zone of printing start in order thatthe printed paper conforms to the proof sheet. However,the longer the time taken for these adjustments, thelarger the waste paper quantity. Hence, shortening thestart time is an important factor leading to the reduction in the waste paper quantity and to improve theproductivity.

1. Introduction
The diversified market needs for the conventionalcommercial offset presses used mainly for large-lot printing are shifting towards medium-and-small lot printing
and short-term delivery production while maintaining
the rapid printing speed. In order to meet this demand,
it is necessary to improve the production efficiency bydrastically reducing the waste paper generated at thetime of printing start in addition to shortening the start
time after the exchange (switching) of printing job. However, there was some limit with the conventional drive
system and operation control method in achieving the
aforesaid goals.
Hence, several types of new mechanism and new systems adopting independent drive motor and shaft-lesssystem were developed to allow wider option to the operating method in order to respond to the market need.
These technologies developed ahead of the German makers, which had taken lead in the field of shaft-less drive,
are used in new commercial offset presses, MAX and SSS,
and are already in operation in the market.

Du T1

2. "MAX-Saver" for Realization of Higher Productivity

Ink supply unit

T6

V3

T2

T1
V2

V1

2.1 Need for shortening the (printing) start time
As shown in Fig. 1
1, printing is carried out by a groupof ink rollers that make a thin film of ink, a plate cylinder equipped with a press plate with the pictures(images) printed on it, a damping roller device that supplies water to the surface of the press plate and a blanket
cylinder that once transfers the pictures on the press
plate. The printed paper (web) is then dried with a drier
and is cut into specified sizes and folded before being
discharged.

Moistening unit

WebGroup ofink rollers

PlatecylinderBlanketcylinderFig. 1 Principle of printing
Shows ink and moistening water used for printing.

Mitsubishi Heavy Industries, Ltd.
Technical Review Vol.41 No.2 (Apr. 2004)*1 Hiroshima Research & Development Center, Technical Headquarters*2 Paper & Printing Machinery Division1

Further, since job changeover in printing is generally
carried out by the unit of several hundred thousand copies, and since a commercial offset press is capable ofprinting five hundred thousand copies per hour, one job
has to be completed in less than 1 hour at the shortest.
Making changeover of jobs dozens of times a day is not arare case, so that shortening the changeover time leads
to improving the operating factor of the press, which isdesired by most customers. In order to meet with thisdemand, we have developed MAX-Saver by making useof the shaft-less technology.
2-2 MAX-Saver and shaft-less drive
MAX-Saver is composed through organic combinationof a large number of functions required for printing suchas various automated devices and press control devices(IPC: Intelligent Press Control), etc. in order to improve
the stability of the press and to respond to the demandof skill-less operation in addition to "shortening the printing start time" and "reducing the waste paper," and is asystem that aims at comprehensive improvement in productivity.
Fig. 2 shows the configuration of MAX-Saver. It isequipped with a shaft-less drive system indispensable
to improving the productivity and the "MAX-Expert"
function that makes the most of the shaft-less drive
system.
The shaft-less drive system replaces drive transfer
shaft, connecting in-feed (feed control) unit, printing unit,
cooling cylinder (for cooling printing paper), web-pass(paper transfer) unit and folding (paper cutting and folding) unit that conventionally required synchronizeddriving, with independent motors for the aforesaid units
to ensure synchronized driving.
The basic technology for this system is the conventional "multi-shaft simultaneous control technology" usedin machine tool, with the substantial differences between
the two being as follows: the phase synchronization andspeed tracking synchronization of the various units fordriving the whole printing machine operate under thecommand of Virtual Master that creates the virtual syn[Major objective]

Improvementof user's
productivity

chronizing signal (SYN); the motors used need highpower and further the printing machine as a load has anextremely large moment of inertia. Hence, the motors
are appropriately used according to the functional requirements of the units and the drivers are provided withdrastically rapid processing capability through highspeed digital technology.
Further, the mounted encoder for feeding back the motor position is capable of processing the optical signal
electrically and then fragmenting the one turn into one
million divisions to ensure accurate and precise phaseindexing. In this way, the deviation between commandsignal and actual phase is instantaneously calculated tocarry out a constant correction in order to allow the motor to run according to the command signal with thesynchronization accuracy within 10 μ m.
MAX-Server makes the effective use of the independent shaft-less motor and the synchronization control
technology to actualize the "shortening of printing starttime" and "reduction of waste paper" in the following
manner.
(1) MAX-Expert
MAX-Expert is a system for reducing the waste paper generated at the time of exchanging the printing
job, and is composed of the SPE (Smart Print End)function to remove the excessive ink in the inking unit
after the job mounted on the aforesaid IPC ends, the
QSI (Quick Start Inking) function to optimize the ink
quantity at the start of job in addition to the BRC(Blanket Liquid Reducing Control) function to reduce
the waste paper at the time of blanket washing andthe web pre-tensioning function, etc.
(2) High-speed, semi-automatic plate exchanger
The plate exchange of each printing unit can be
carried out in parallel by using the shaft-less technology capable of independent drive, ensuring the
reduction of time from conventional 12 min to 4 min.
The independent drive of each printing unit causes
the phase deviation of colors to get automatically synchronized at the time of printing start.

[Problems to be solved][Solutions]

Ease in operability

Improvement invisibility of touch panel

Reduction ofwaste paper

MAX-Expert

MAX-NetConcentrated lubrication
New-type ink key

Ease in maintenanceImproved maintainability
High efficiency ofjob exchange

Shaft-less drive

High-speed, semi-automatic
plate exchange
Automatic discharge of
defective paper

Fig. 2 Configuration of MAX-Saver
A system for comprehensive realization of improved productivity.

Mitsubishi Heavy Industries, Ltd.
Technical Review Vol.41 No.2 (Apr. 2004)2

(3) New type ink key
The ink sticking in the piano-type keys arranged
in 28 rows to feed thin film of printing ink (3050 μ m) is prevented by using the Teflon coated tray,
while the key opening accuracy is maintained to reduce the color adjusting time at the printing starttime.
(4) Automatic discharge mechanism for defective paper
A printing operator had to discharge the paper andmake other confirmations before changing the folding style in order to prevent the paper from getting
jammed in the folding section, which was a burden at
the time of job exchange. This burden has been reduced through automated mechanism.
Besides, a large-size touch panel with enhanced visibility and operability, a network of peripheral machines
for the press connected to the management system andpre-press system of the user, a digital work flow systemenabling presetting of the printing machine based on
printing conditions and picture (image) information are
also available.
2-3 Shortening of the start time and reduction of
printing waste paper
Described below is the effect of the functions of theaforesaid MAX-Saver. Fig. 3 shows an example of thestart time shortened by MAX-Saver, with maximum
shortening seen at the time of plate exchange where thework can be carried out in parallel and at the time offolding style exchange. As a result, the start time has
been shortened from 24 min to 9 min as compared withconventional Mitsubishi printing machine. The start timein actual printing, however, differs according to the proficiency of the operator and other unsteady factors.
Nevertheless, the time needed conventionally for preparation and start has obviously been reduced to half.
Next, we would like to describe the problem of how to
reduce the printing waste paper (paper to be abolished

Machine speed (rpm)Precedingjob endbecause of defective color tone, deviation of register, defective cutting and folding. It is necessary to consider
from the stage where printing jobs ends in order to takemeasure for reducing the waste paper. An operation chart
aimed at reducing the waste paper is shown in Fig. 44,where preparation for the next job is made at the stage
when the equipment is shut down after preceding job
comes to an end. This is the print reducing function (SPE)and the blank paper reducing function (BRC2).
The SPE function irons out the uneven ink film on
the roller depending on the presence/absence of image(picture) and reduces the required ink level to the minimum level, so that if the next job is started withoutcarrying out SPE, a substantially long time is required
for stabilizing the color tone.
The BRC2 is an operation of cleaning the ink left as
picture on the blanket, i.e. the plate cylinder, and must
be carried out in order to prevent the waste paper generation due to the picture of the preceding job. The
blanket cleaning was conventionally carried out at medium-speed (200 rpm) zone with the paper running,

Preparation time for printing (min)

30

SPE

: Others: Confirmation: Printing adjustment: Preparation and start: Folding changeover: Plate exchange: Paper exchange: Blanket cleaning

20
15
10
5
0

Conventional
machineMAX

Fig. 3 Effect of shortening the preparation time for printing start
Indicates the preparation items before printing start and effect ofshortening the time by MAX-Saver.

9 min (conventional: 24 min)"Single-make ready"Pre-tension
High-speed, semi-automatic
plate exchange
1 000

Shortened by
15 min25

Next job
start
Pre-inking
SAC

BRC

BRC 2

400

Normal
paper

200
50
0
Slow-blow
paster

Discharge of
defective paper

Change inpaper path

Foldingchangeover

Temperaturerise of drier

Fig. 4 Operation chart for waste paper reduction
Indicates the flow between "end of preceding job" and "start of following job."

Mitsubishi Heavy Industries, Ltd.
Technical Review Vol.41 No.2 (Apr. 2004)3

turning all paper during the cleaning process into waste
paper. The adoption of shaft-less function, however, allows different-speed control to feed paper at the lowest
speed (10 rpm) although the blanket cleaning is carriedout at the conventional medium-speed zone, keeping thewaste paper generation to minimum level.
This completes the preparation for the next job before the equipment is started again. At this stage,
however, phase focusing of all units (paper traveling, infeeding, printing and folding units) as well as web tension
control (pre-tension function) is carried out. This completes the mechanical preparations, when the BRC
function gets activated to discharge the cleaning fluid
from the blanket. The cleaning fluid is removed by using the turning force, while suppressing the waste paper
generation by keeping the paper traveling speed at theminimum level as in the case of the aforesaid blanket
cleaning. After printing starts, the color tone, register,
cutting and folding are adjusted before accelerating to
the normal speed. The conventional acceleration at 2030 rpm/sec caused the color tone and register to differ
from the proof sheet because of the delay in ink supply
and change in tension during paper traveling, resulting
in the generation of waste paper.
This waste paper generation can be prevented throughstep acceleration control (SAC). The SAC is a control system where the printing speed is increased stepwise toenable the automatic control units for ink supply, regist e r a n d c u t t i n g t o f o l l o w a c c o r d i n g l y, w i t h t h eaccelerating speed remaining the same. In conventionalcase, acceleration of printing speed to maximum level

3.1 Waste paper reduction and productivity
All functions were independently verified during theprocess of development to confirm the practical effectand to judge the productivity. However, in order to confirm the serviceability during commercial operation at
the user side, it was necessary to install the system tothe user's printing machine. Therefore, MAX-Saver was
actually installed to the user's printing machine to confirm the performance in actual commercial operation.
MHI conventional printing machine was used as an object of comparison.
Fig. 6 shows the comparison per waste paper cause,with the waste paper generation rate expressed in termsof 100% of the conventional printing machine. The difference between actually measured and estimated(estimated at the verification stage) values of waste paper rate at the start of printing is considered to be causedby the difference in waste paper criteria between the user

Maximum speed
Normalacceleration

Adjustment
Waste
paper

Normalpaper

Waste paper generation rate (%)

Machine speed

3. Practical Effect of MAX-Saver

Substantiallynormal paper

Conventional acceleration
Printing
adjustmentend

immediately after printing start caused phase deviation
between printing units and folding units because of the
distortion of drive shaft and backlash of gears, resulting
in deviation of register and cutting position and leading
to the generation of waste paper. In the case of SAC system, however, the waste paper generated at the time ofacceleration can practically be prevented, in spite of thetime needed until the normal speed is gained.
Fig. 5 shows the effect of SAC system, indicating thatno waste paper is generated during acceleration, whereas
the production quantity for the same time gets reduced.
However, the time needed for making up for the inadequacy in production quantity is estimated to be 2.5 min,which can be accomplished through normal-speed printing. Thus, through adoption of the automation technology
making use of the shaft-less technology and innovated
MAX-Saver, the preparation time could be drasticallyshortened, contributing to reducing the printing start
time by half and improving the productivity by reducing
the generation of waste paper.

Machine speed

SAC acceleration
Maximum speed
Reducible
waste
paper
Step acceleration
Adjustment

Normalpaper

Fig. 5 Effect of SAC control adoption
Indicates the waste paper generation as compared with theconventional method.

100

Conventional MHI machine
waste paper rate regarded as 100%
Estimated value

Actuallymeasured
value

50

0

PrintedOverall
Waste paper Waste paper
waste paperat printing waste paper
duringend
printing

Fig. 6 Comparison per waste paper causing factor
Waste paper generation rate in the process of printing compared withthat of conventional MHI machine.

Mitsubishi Heavy Industries, Ltd.
Technical Review Vol.41 No.2 (Apr. 2004)

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25

Frequency (%)

20

Waste paper generation
reduced by 1100 copies

Average waste paper
generation: 1 500 copies
for the machine equippedwith MAX-Saver

Average waste paper
generation for the current
machine: 2 600 copies

15

10

5

0

800

1600

3 200

2 400

Printed out waste paper quantity (copies)
Fig. 7 Histogram of printed waste paper quantity at user side
Indicates the waste paper generation frequency per job during a period of 1 month.
Table 1 Estimation of productivity
Numberof
product
copiesfor 1 job
(copy)

Effect of saving through Effect of shortening
waste paper reduction the operating time
Annualsavingamount(yen)ment and research MAX-Saver has been successively
mounted to the prints. The investigation on records was
carried out for one month at the customer side to reconfirm the effects. Fig. 7 shows the histogram of printing
waste paper quantity for each printing job, where theprinting waste paper immediately after the changeover(exchange) of printing job is summed up, indicating that,compared with the conventional offset print, an average
waste paper reduction of 1 100 pieces/job has been confirmed through IPC and SPE.

Productivityof
MAX-Saver(yen)

Quantity ofannually
reducedwaste paper(copy)

Annualsavingamount(yen)

Ratio ofreducedtime(%)

20 0003 242 000

9 730 000

36

5 840 000 15 560 000

60 0003 322 000

9 970 00025

3 770 000 13 730 000(Estimation conditions)
Waste paper unit price: 3 yen, Number of personnel: 3 persons,Annual reward: 4 million yen, Machine running cost: 255 000 yen per month

4. Conclusion
and MHI. The average waste paper rate at the user side
is reduced to 51%. The average waste paper quantity forthe press equipped with MAX-Server is found to be 1 200
pieces against 2 400 pieces of the conventional press, withthe annual reduction of waste paper generation amounting to 3 million pieces (sheets).
Table 1 shows the productivity estimated on the basis of small- and medium-size lot production based on
the aforesaid results. The estimation shows that the effect is particularly large for small-lot production, which
is apparently attributed to the features of MAX-Saver"shortening the printing start time" and "reduction ofwaste paper"-acting more effectively because of thehigher frequency of printing job (in the case of small-lot
production).
3.2 Record at the customer side
A total of 23 units of shaft-less commercial offset
prints have so far been delivered since the first offset
print was launched in April 2001, and after its develop-

Shigeo Makino

The shaft-less technology has become indispensable
to commercial offset prints. MAX-Saver making most effective use of the technology largely contributes to saving
resources and improving productivity, the common objectives of users as well as manufacturers. By shortening
the printing start time by half and reducing the quantity of waste paper, the operating factor of the printing
machine can be increased to improve the productivity.
This in turn leads to reducing the annual cost estimatedto more than ten million yen. We are planning to improve MAX-Saver to make it easier to use, to develop
the acceleration system at printing to step-less acceleration control from step acceleration control (SAC) in orderto make further reduction of time and to save resources.
Further, we are determined to continue our research anddevelopment on commercial offset prints to meet thedemand for multi-type, small-lot production without
waste in order to respond to the expectation of our customers.

Masakazu Akatsuka

Tatsuo Fujikawa

Shinichiro Senoo

Hiroshi Kobara

Mitsubishi Heavy Industries, Ltd.
Technical Review Vol.41 No.2 (Apr. 2004)

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