Graphic technology — Determination of the energy consumption of digital printing devices including transitional and related modes

This document provides directions for measuring and calculating the electricity consumption of any format of digital production press, whose modes, other than production printing mode, play a significant role in the comprehensive energy consumption. It excludes digital presses designed to print substrates other than paper or plastic and conventional printing presses fitted with digital inkjet printing heads. It can be used to compare the energy efficiency figures for different machine combinations: best-quality (slowest), highest-productivity (fastest) or other alternative combinations.

Technologie graphique — Détermination de la consommation d’énergie des dispositifs d’impression numérique en modes transitoires et connexes

Grafična tehnologija - Ugotavljanje porabe energije digitalnih tiskarskih naprav, vključno s prehodnimi in povezanimi načini delovanja

General Information

Status
Published
Publication Date
03-Dec-2018
Current Stage
6060 - International Standard published
Start Date
04-Dec-2018
Completion Date
04-Dec-2018

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INTERNATIONAL ISO
STANDARD 21632
First edition
2018-12
Graphic technology — Determination
of the energy consumption of digital
printing devices including transitional
and related modes
Technologie graphique — Détermination de la consommation
d’énergie des dispositifs d’impression numérique en modes
transitoires et connexes
Reference number
ISO 21632:2018(E)
ISO 2018
---------------------- Page: 1 ----------------------
ISO 21632:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 21632:2018(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 General conditions ............................................................................................................................................................................................. 6

4.1 Condition, age and machine configuration ..................................................................................................................... 6

4.2 Connection conditions ...................................................................................................................................................................... 7

4.3 Printing conditions and operational modes .................................................................................................................. 7

4.3.1 General...................................................................................................................................................................................... 7

4.3.2 Measurements referred to in ISO 20690 as well as in this document ............................... 8

4.3.3 Additional measurements required for this document to estimate

comprehensive energy consumption ............................................................................................................. 9

4.4 Measuring conditions ........................................................................................................................................................................ 9

4.5 Test procedures ...................................................................................................................................................................................10

4.5.1 General...................................................................................................................................................................................10

4.5.2 Power measurement for production print mode .............................................................................10

4.5.3 Procedures to determine power consumption of other relevant modes
for the calculation of comprehensive energy consumption of the digital

printing device ................................................................................................................................................................13

4.5.4 Combined test flow .....................................................................................................................................................20

4.6 Calculation and documentation of measurement results ...............................................................................22

4.6.1 General...................................................................................................................................................................................22

4.6.2 Formulae for the average power P, the average productivity S and the

nominal energy efficiency E during continuous production printing ...................23

nom

4.6.3 Rounding rule of data to be reported ..........................................................................................................24

4.7 Calculation of comprehensive daily energy consumption based on a typical job

structure using power measurement values .............................................................................................................24

4.7.1 Power measurement values ................................................................................................................................24

4.7.2 Typical job structure .................................................................................................................................................25

4.7.3 Calculation of daily energy consumption ................................................................................................26

4.7.4 Calculation of effective energy efficiency ................................................................................................26

Annex A (informative) Measurement data sheet ..................................................................................................................................27

Annex B (informative) Calculation of comprehensive energy consumption ...........................................................32

Annex C (informative) Calculation of carbon footprints for print media products ..........................................35

Bibliography .............................................................................................................................................................................................................................37

© ISO 2018 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 21632:2018(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso

.org/iso/foreword .html.

This document was prepared by Technical Committee ISO/TC 130, Graphic technology.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2018 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 21632:2018(E)
Introduction

The energy requirement of digital production printing devices varies considerably across technologies,

output formats, and productivity and quality expectations. Run length influences the overall energy

usage, so the energy consumption of devices used for relatively short run lengths is accompanied by the

relatively high amounts of transitional energy, including surge power, required to complete the print

run. Operating transitions contribute to the overall energy profile throughout the course of operations,

with frequent interventions between production printing modes.

As a proportion of the overall energy requirement for short run length jobs, transitional energy,

including the surge energy, and waiting energy, including preparatory maintenance, will be substantial.

This means that in order for the graphics industry to have accurate energy consumption data,

directions are required to assist stakeholders in making accurate calculations for digital production

printing devices, whose modes, other than production printing mode, play a significant role in the

comprehensive energy consumption. This includes digital printing machines used to produce sign and

display work, commemorative prints, photo books and similar high-value, on-demand print in narrow

and wide formats.

This document provides directions for measuring any format of digital production press, whose modes,

other than production printing mode, play a significant role in the comprehensive energy consumption.

This document can be used to compare the energy efficiency figures for different machine set ups: best-

quality (slowest), highest-productivity (fastest) or other alternative combinations.

Application of this document provides the energy efficiency figures that correspond to the energy

consumption for a digital printing device. These values can be used to inform the individual production

scenarios covering different shifts, printing materials and other factors typical of the graphic arts.

Energy usage is generally estimated according to the connected load of a machine. The connected load

is the machine’s potential maximum power consumption. But calculated values do not necessarily

reflect the machine’s energy consumption. Actual energy consumption often differs significantly from

estimated values. Power consumption data across devices can therefore not be accurately compared,

since the calculations are unlikely to have followed a common framework that takes into account the

influence of peripheral equipment such as IR or UV dryers. Nor can they accommodate differences in

measurement cycles.

The universal availability of verifiable energy consumption data will enable print machinery buyers,

printers and their customers to assess the power consumption of machines. However, the user of this

document should understand that the effectiveness of power does not determine acceptable quality

levels for the output that customers may require or expect. Power consumption is an important part of

all the output requirements and quality expectation. This data can be used in life cycle analyses (LCA)

and to calculate the carbon footprint of a printing system and of printed matter. Energy efficiency can

be reported in various ways, such as the number of prints printed per kWh. This information can be

used to:
— provide data for the LCA of a printing device;

— assess the power consumption and energy efficiency of digital printing production machines and

peripheral devices;
— estimate operating costs for investment planning;
— benchmark the energy efficiency of digital production presses;
— calculate the CO footprint of printed matter;

— encourage the energy efficiency improvements of digital printing devices over time;

— provide data to enable companies to claim environmental subsidies;
— provide data for carbon offsetting purposes.
© ISO 2018 – All rights reserved v
---------------------- Page: 5 ----------------------
ISO 21632:2018(E)

This document defines how to calculate the electrical energy requirements and therefore the energy

efficiency of digital printing devices.

This document can be used to determine the energy efficiency of any format of digital production press,

whose modes, other than production printing mode, play a significant role in the comprehensive energy

consumption.

Care should be taken when comparing the results obtained from this document that the devices being

compared were set up to produce the same print quality using comparable types of printing technology,

process and device configurations.
vi © ISO 2018 – All rights reserved
---------------------- Page: 6 ----------------------
INTERNATIONAL STANDARD ISO 21632:2018(E)
Graphic technology — Determination of the energy
consumption of digital printing devices including
transitional and related modes
1 Scope

This document provides directions for measuring and calculating the electricity consumption of any

format of digital production press, whose modes, other than production printing mode, play a significant

role in the comprehensive energy consumption. It excludes digital presses designed to print substrates

other than paper or plastic and conventional printing presses fitted with digital inkjet printing heads.

It can be used to compare the energy efficiency figures for different machine combinations: best-quality

(slowest), highest-productivity (fastest) or other alternative combinations.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

IEC 60204-1, Safety of machinery — Electrical equipment of machines — Part 1: General requirements

3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
digital printing machine
digital printing device
digital press

machine used in commercial/industrial applications where the printing image is produced in the machine

from data stored in digital form and transferred to the substrate without the use of a printing plate

[SOURCE: ISO 12643-2:2010, 3.9, modified — “digital printing device” and “digital press” have been

added to the term.]
3.2
electrical energy

electricity converted to other forms of energy (power, light, heat) for the operation of machines and

devices

Note 1 to entry: Electricity generated in this way is calculated using the following formula:

Eu=×ti tdt
() ()
where u(t) and i(t) are the instantaneous values of voltage and current.
© ISO 2018 – All rights reserved 1
---------------------- Page: 7 ----------------------
ISO 21632:2018(E)
3.3
energy usage
power required for the operation of a given process over time

Note 1 to entry: Energy usage or electric energy consumption is typically measured in watt-seconds (Ws),

kilowatt-hours (kWh) or watt-hours (Wh).
3.4
connected load

theoretically possible maximum power consumption of a machine, which can be expected when

components of the printing machine are running at maximum load

Note 1 to entry: The connected load is the power specified by the manufacturer and used to rate the electrical

power supply of the printing house (power rating, fuse rating, cable cross section). This ensures fail-safe

operation of the machine under any possible operating condition. Determination of the connected load value has

not been uniformly regulated so machine manufacturers handle it differently.

Note 2 to entry: The connected load should not be used to calculate a device’s actual power consumption. This is

always lower and in most applications, it is significantly lower.
[SOURCE: ISO 20690:2018, 3.3]
3.5
operational power consumption

power consumption of a machine in a defined operating condition or operational mode

Note 1 to entry: Typical operating modes are sleep, print-ready and production (also known as active mode).

3.6
active power
power available for conversion into other types of power

Note 1 to entry: mechanical, thermal or chemical power. In general, the active power of a consumer in a periodic

AC voltage system can be determined with the formula
PT=×1/ ut it dt
() ()
where T is the desired period.
Note 2 to entry: Standard units are watts (W) and kilowatts (kW).
3.7
power meter

power analyser, which records voltages and currents as continuous values to determine power

parameters
Note 1 to entry: These are high-precision devices designed for industrial use.
3.8
sleep mode

period when a printing machine is switched on, not running and operating with lower power than print-

ready mode

Note 1 to entry: A reduced power state that a printing device automatically enters after a set period of inactivity

(a.k.a. default delay time). Sleep mode permits operation of all product features (including maintenance of

network connectivity), albeit with a possible delay to transition into print-ready or production mode.

2 © ISO 2018 – All rights reserved
---------------------- Page: 8 ----------------------
ISO 21632:2018(E)
3.9
print-ready mode

period when a printing machine is switched on with all assembled components (pre- and post-

processing units) prepared to deliver outputs in the shortest time after a print order is given, compared

with other waiting modes, such as sleep mode or off mode
3.10
production print mode
steady production print mode
period when a printing machine is printing live jobs

Note 1 to entry: A production print mode is characterized by a stable power consumption, when the printing

machine is printing in a representative and typical fashion.
3.11
RIP
raster image processor which converts data into a raster bit stream or bitmap
3.12
machine combination

software, hardware and print media which has a direct influence on the resulting print image quality

EXAMPLE Best-quality combination = device configuration (hardware) + substrate (media) + print mode

(software).

Note 1 to entry: RIP and print mode settings are examples of machine combination.

Note 2 to entry: When the settings depend heavily on the RIP and printing technology, the machine combination

can also be referred to as the digital printing combination.
3.13
device configuration
physical hardware equipment included in a given production line
[SOURCE: ISO 20690:2018, 3.14]
3.14
basic device configuration

standard hardware equipment configuration as defined by the manufacturer, owner or user of the

device for the type of printed products or market for which the press is being used

3.15
alternative device configuration
physical hardware configuration differing from the basic device configuration
[SOURCE: ISO 20690:2018,3.16]
3.16
print mode

collection of settings, that are used to control a given device configuration via software (RIP) to enable,

disable or otherwise influence the operation of that device

EXAMPLE Using four colours on a machine capable of seven colours, varying the resolution, changing the

speed or enabling duplex printing.
3.17
alternative print mode

collection of settings different from the print modes used for obtaining the best-quality or best-

productivity combinations and used for defining additional combinations
© ISO 2018 – All rights reserved 3
---------------------- Page: 9 ----------------------
ISO 21632:2018(E)
3.18
imposition

fitting of test images (with no change to size) into the screen, sheet or unit length without overlapping

[SOURCE: ISO 20690:2018, 3.19]
3.19
imposition rate

ratio between the area of the imposed test images and the total area of the screen, sheet or unit

length paper

Note 1 to entry: In this document, the imposition rate is used to calculate the equivalent A4 or Letter pages

printed on larger paper formats, regardless of the original image size.
[SOURCE: ISO 20690:2018, 3.20]
3.20
nominal energy efficiency
nom

number of printed equivalent A4 pages or m per kWh, measured in cruising state of production print

mode, excluding the first page

Note 1 to entry: The number of output pages and the corresponding integral power are measured over the

specified time.
3.21
effective energy efficiency
eff

number of printed equivalent A4 pages or m per kWh, whose energy covers not only production print

mode but also other relevant modes, such as print-ready, sleep, transitional and maintenance modes

3.22
transitional mode
start-up mode

period connecting two stable modes with different average power consumptions, i.e. “off mode and print-

ready mode”, “sleep mode and print-ready mode” and “print-ready mode and production print mode”

3.23
maintenance mode

period required to maintain quality of devices, conducted regularly, for example prior to starting

production print
3.24
first page print time
FPPT

number of seconds or minutes between the initiation of the job and the completion of the first cut sheet

print or the completion of the first unit-page print imposed across the width of roll paper

Note 1 to entry: FPPT is measured from a stable condition of the relevant mode. For example, print-ready mode

after the completion of a previous job may need a considerable time to stabilize because the heating unit needs

several minutes for cooling to a stable, ready condition. If FPPT were measured before cooling off, the measured

value could be shorter than that measured from a stable print-ready state, creating inconsistencies.

Note 2 to entry: In small format devices, FPPT is known as “first print out time” (FPOT). See ISO/IEC 17629:2014.

3.25
warm-up time

time required by the printing device to warm up from off mode, given by the difference in FPPT between

off mode and print-ready mode
4 © ISO 2018 – All rights reserved
---------------------- Page: 10 ----------------------
ISO 21632:2018(E)
3.26
recovery time

time required by the printing device to recover from sleep mode given by the difference in FPPT between

sleep mode and print-ready mode
3.27
copy
test form printed on a substrate regardless of being printed simplex or duplex

EXAMPLE 100 copies = 100 test forms printed on 100 sheets (simplex) or 50 sheets (duplex) or 100 images of

the test form imposed on the given substrate.
3.28
consistency check

method for determining the stability and validity of two sequential measurements before averaging

the results

EXAMPLE “5 % consistency” is satisfied when the first result value A and the second result value B meet

0,95 ≤ 2A / (A + B) ≤ 1,05, where result value means reporting value (e.g. XX pages/kWh for “energy efficiency”).

3.29
image quality adjustment

modifications made during printing to ensure print image quality that forces the printing system to

pause production for a short period of time

Note 1 to entry: Image quality adjustments depend on many parameters such as test form area coverage or

required quality level.

Note 2 to entry: Some printing devices will make image quality adjustments during printing to ensure print

quality, where the devices continue moving without delivering any printouts.
3.30
unit under test
UUT
the digital printing device which is being measured
3.31
dummy print
preliminary job conducted in order to bring the UUT to print-ready mode
3.32
trailing edge

ridge line of printed cut sheet or imposed image form on roll paper, situated at the end along the

transportation direction
3.33
job structure

typical work flow of the printing press per period (e.g. day) with power consumption levels along

sequential modes
3.34
tonal coverage
cumulative colourant percentage

EXAMPLE A full sheet of 100 % deep black in CMYK has a tonal coverage = “400”. The colourant coverage is

defined by the tone value as specified in ISO 12647-1.

Note 1 to entry: Typical coverage based on one colour plane are: light — 1 % to 9 %, medium — 10 % to 35 %,

heavy — 36 % above.
[11]
[SOURCE: XJDF-Specification-2.0 Draft 2017-05-11 ]
© ISO 2018 – All rights reserved 5
---------------------- Page: 11 ----------------------
ISO 21632:2018(E)
4 General conditions
4.1 Condition, age and machine configuration

How much power a digital printing device and peripheral devices uses is subject to many influences

such as the selected print mode, equipment characteristics and their condition, ambient conditions,

selected print speed, additional machine settings and the printing substrates used, especially their

drying requirements.

The operational climate should comply with the following conditions and the actual conditions shall be

documented:
— temperature: 20 °C–25 °C, and
— relative air humidity: 45 %–60 %.

Measurement of the operational climate parameters shall be made immediately before the start of the

power measurement at a distance of 1 m from the front side of the paper input, at a height of 1,60 m

above floor level.

The manufacturer, owner or user of a printing system shall determine a basic or standard device

configuration that can be used for testing the two required machine combinations, best-quality and

best-productivity. These two combinations shall be used for printing and measuring, to reflect the

influence of the digital press’s configuration on its power consumption and energy efficiency data.

— Best-quality (BQ) combination: The manufacturer, owner or user of a printing system shall select

a device configuration, print mode and substrate for achieving the best possible saleable print

quality. All colourants of the system shall be used.

— Best-productivity (BP) combination: The manufacturer, owner or user of a printing system shall

use the same device configuration as used in the best-quality combination with a print mode and

substrate for achieving the highest possible saleable productivity.

— Alternative (AL) combination: Using the same device configuration, alternative print modes

are allowed (e.g. monochrome printing of a colour test page on a colour device, printing with four

colours on a device capable of seven colours or changing the print resolution) and shall be reported

as an alternative combination so as not to be confused with the mandatory best-quality or best-

productivity combinations.

On a monochrome printing device, monochrome printing is not considered to be an AL combination and

is to be tested in both BQ and BP combinations, if possible.

Electrophotographic processes have significantly fewer parameters affecting energy efficiency than

inkjet printing. However, printing systems are available that allow for a change in print image quality,

for example by adding a further colourant. If the printing press to be evaluated does not allow for a

meaningful separation between BQ and BP, one machine configuration may be used. This machine

combination shall be labelled best-quality/best-productivity (BQ/BP).

AL device configurations may include additional pre- or post-handling or print and output enhancement

equipment (e.g. sheeting, folding, binding, seven colours, substrate enhancement or manipulation)

under the condition that the additional equipment is built in as part of the production line (in-line). Any

AL device configurations shall be seen and reported as a different device configuration and tested in

both BQ and BP combinations as defined by the user of this document.

A PDF file of the output image shall be attached to the test report to show the test has been conducted

with suitable image quality.

To demonstrate that prints are of adequate quality, colour accuracy should fulfil the requirements of

ISO 12647-8:2012, 5.2. This ensures that the required ink coverage is used for test prints. However, this

test does not fully measure the colour accuracy of the printing system.
6 © ISO 2018 – All rights reserved
---------------------- Page: 12 ----------------------
ISO 21632:2018(E)
4.2 Connection conditions

Digital printing systems, including pre-and post-processing units shall use one- or three-phase

connection, 50 Hz–60 Hz and 100 V–650 V. The power supply quality and the voltage tolerance shall

comply with IEC 60204-1 or equivalent.

Measurements may be performed on more than one outlet. Typical connection points are:

— main printing unit (main switch cabinet);
— paper feeder;
— pape
...

SLOVENSKI STANDARD
SIST ISO 21632:2020
01-april-2020

Grafična tehnologija - Ugotavljanje porabe energije digitalnih tiskarskih naprav,

vključno s prehodnimi in povezanimi načini delovanja

Graphic technology - Determination of the energy consumption of digital printing devices

including transitional and related modes

Technologie graphique - Détermination de la consommation d’énergie des dispositifs

d’impression numérique en modes transitoires et connexes
Ta slovenski standard je istoveten z: ISO 21632:2018
ICS:
37.100.10 Reprodukcijska oprema Reproduction equipment
SIST ISO 21632:2020 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST ISO 21632:2020
---------------------- Page: 2 ----------------------
SIST ISO 21632:2020
INTERNATIONAL ISO
STANDARD 21632
First edition
2018-12
Graphic technology — Determination
of the energy consumption of digital
printing devices including transitional
and related modes
Technologie graphique — Détermination de la consommation
d’énergie des dispositifs d’impression numérique en modes
transitoires et connexes
Reference number
ISO 21632:2018(E)
ISO 2018
---------------------- Page: 3 ----------------------
SIST ISO 21632:2020
ISO 21632:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved
---------------------- Page: 4 ----------------------
SIST ISO 21632:2020
ISO 21632:2018(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 General conditions ............................................................................................................................................................................................. 6

4.1 Condition, age and machine configuration ..................................................................................................................... 6

4.2 Connection conditions ...................................................................................................................................................................... 7

4.3 Printing conditions and operational modes .................................................................................................................. 7

4.3.1 General...................................................................................................................................................................................... 7

4.3.2 Measurements referred to in ISO 20690 as well as in this document ............................... 8

4.3.3 Additional measurements required for this document to estimate

comprehensive energy consumption ............................................................................................................. 9

4.4 Measuring conditions ........................................................................................................................................................................ 9

4.5 Test procedures ...................................................................................................................................................................................10

4.5.1 General...................................................................................................................................................................................10

4.5.2 Power measurement for production print mode .............................................................................10

4.5.3 Procedures to determine power consumption of other relevant modes
for the calculation of comprehensive energy consumption of the digital

printing device ................................................................................................................................................................13

4.5.4 Combined test flow .....................................................................................................................................................20

4.6 Calculation and documentation of measurement results ...............................................................................22

4.6.1 General...................................................................................................................................................................................22

4.6.2 Formulae for the average power P, the average productivity S and the

nominal energy efficiency E during continuous production printing ...................23

nom

4.6.3 Rounding rule of data to be reported ..........................................................................................................24

4.7 Calculation of comprehensive daily energy consumption based on a typical job

structure using power measurement values .............................................................................................................24

4.7.1 Power measurement values ................................................................................................................................24

4.7.2 Typical job structure .................................................................................................................................................25

4.7.3 Calculation of daily energy consumption ................................................................................................26

4.7.4 Calculation of effective energy efficiency ................................................................................................26

Annex A (informative) Measurement data sheet ..................................................................................................................................27

Annex B (informative) Calculation of comprehensive energy consumption ...........................................................32

Annex C (informative) Calculation of carbon footprints for print media products ..........................................35

Bibliography .............................................................................................................................................................................................................................37

© ISO 2018 – All rights reserved iii
---------------------- Page: 5 ----------------------
SIST ISO 21632:2020
ISO 21632:2018(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso

.org/iso/foreword .html.

This document was prepared by Technical Committee ISO/TC 130, Graphic technology.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2018 – All rights reserved
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Introduction

The energy requirement of digital production printing devices varies considerably across technologies,

output formats, and productivity and quality expectations. Run length influences the overall energy

usage, so the energy consumption of devices used for relatively short run lengths is accompanied by the

relatively high amounts of transitional energy, including surge power, required to complete the print

run. Operating transitions contribute to the overall energy profile throughout the course of operations,

with frequent interventions between production printing modes.

As a proportion of the overall energy requirement for short run length jobs, transitional energy,

including the surge energy, and waiting energy, including preparatory maintenance, will be substantial.

This means that in order for the graphics industry to have accurate energy consumption data,

directions are required to assist stakeholders in making accurate calculations for digital production

printing devices, whose modes, other than production printing mode, play a significant role in the

comprehensive energy consumption. This includes digital printing machines used to produce sign and

display work, commemorative prints, photo books and similar high-value, on-demand print in narrow

and wide formats.

This document provides directions for measuring any format of digital production press, whose modes,

other than production printing mode, play a significant role in the comprehensive energy consumption.

This document can be used to compare the energy efficiency figures for different machine set ups: best-

quality (slowest), highest-productivity (fastest) or other alternative combinations.

Application of this document provides the energy efficiency figures that correspond to the energy

consumption for a digital printing device. These values can be used to inform the individual production

scenarios covering different shifts, printing materials and other factors typical of the graphic arts.

Energy usage is generally estimated according to the connected load of a machine. The connected load

is the machine’s potential maximum power consumption. But calculated values do not necessarily

reflect the machine’s energy consumption. Actual energy consumption often differs significantly from

estimated values. Power consumption data across devices can therefore not be accurately compared,

since the calculations are unlikely to have followed a common framework that takes into account the

influence of peripheral equipment such as IR or UV dryers. Nor can they accommodate differences in

measurement cycles.

The universal availability of verifiable energy consumption data will enable print machinery buyers,

printers and their customers to assess the power consumption of machines. However, the user of this

document should understand that the effectiveness of power does not determine acceptable quality

levels for the output that customers may require or expect. Power consumption is an important part of

all the output requirements and quality expectation. This data can be used in life cycle analyses (LCA)

and to calculate the carbon footprint of a printing system and of printed matter. Energy efficiency can

be reported in various ways, such as the number of prints printed per kWh. This information can be

used to:
— provide data for the LCA of a printing device;

— assess the power consumption and energy efficiency of digital printing production machines and

peripheral devices;
— estimate operating costs for investment planning;
— benchmark the energy efficiency of digital production presses;
— calculate the CO footprint of printed matter;

— encourage the energy efficiency improvements of digital printing devices over time;

— provide data to enable companies to claim environmental subsidies;
— provide data for carbon offsetting purposes.
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This document defines how to calculate the electrical energy requirements and therefore the energy

efficiency of digital printing devices.

This document can be used to determine the energy efficiency of any format of digital production press,

whose modes, other than production printing mode, play a significant role in the comprehensive energy

consumption.

Care should be taken when comparing the results obtained from this document that the devices being

compared were set up to produce the same print quality using comparable types of printing technology,

process and device configurations.
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SIST ISO 21632:2020
INTERNATIONAL STANDARD ISO 21632:2018(E)
Graphic technology — Determination of the energy
consumption of digital printing devices including
transitional and related modes
1 Scope

This document provides directions for measuring and calculating the electricity consumption of any

format of digital production press, whose modes, other than production printing mode, play a significant

role in the comprehensive energy consumption. It excludes digital presses designed to print substrates

other than paper or plastic and conventional printing presses fitted with digital inkjet printing heads.

It can be used to compare the energy efficiency figures for different machine combinations: best-quality

(slowest), highest-productivity (fastest) or other alternative combinations.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

IEC 60204-1, Safety of machinery — Electrical equipment of machines — Part 1: General requirements

3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
digital printing machine
digital printing device
digital press

machine used in commercial/industrial applications where the printing image is produced in the machine

from data stored in digital form and transferred to the substrate without the use of a printing plate

[SOURCE: ISO 12643-2:2010, 3.9, modified — “digital printing device” and “digital press” have been

added to the term.]
3.2
electrical energy

electricity converted to other forms of energy (power, light, heat) for the operation of machines and

devices

Note 1 to entry: Electricity generated in this way is calculated using the following formula:

Eu=×ti tdt
() ()
where u(t) and i(t) are the instantaneous values of voltage and current.
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3.3
energy usage
power required for the operation of a given process over time

Note 1 to entry: Energy usage or electric energy consumption is typically measured in watt-seconds (Ws),

kilowatt-hours (kWh) or watt-hours (Wh).
3.4
connected load

theoretically possible maximum power consumption of a machine, which can be expected when

components of the printing machine are running at maximum load

Note 1 to entry: The connected load is the power specified by the manufacturer and used to rate the electrical

power supply of the printing house (power rating, fuse rating, cable cross section). This ensures fail-safe

operation of the machine under any possible operating condition. Determination of the connected load value has

not been uniformly regulated so machine manufacturers handle it differently.

Note 2 to entry: The connected load should not be used to calculate a device’s actual power consumption. This is

always lower and in most applications, it is significantly lower.
[SOURCE: ISO 20690:2018, 3.3]
3.5
operational power consumption

power consumption of a machine in a defined operating condition or operational mode

Note 1 to entry: Typical operating modes are sleep, print-ready and production (also known as active mode).

3.6
active power
power available for conversion into other types of power

Note 1 to entry: mechanical, thermal or chemical power. In general, the active power of a consumer in a periodic

AC voltage system can be determined with the formula
PT=×1/ ut it dt
() ()
where T is the desired period.
Note 2 to entry: Standard units are watts (W) and kilowatts (kW).
3.7
power meter

power analyser, which records voltages and currents as continuous values to determine power

parameters
Note 1 to entry: These are high-precision devices designed for industrial use.
3.8
sleep mode

period when a printing machine is switched on, not running and operating with lower power than print-

ready mode

Note 1 to entry: A reduced power state that a printing device automatically enters after a set period of inactivity

(a.k.a. default delay time). Sleep mode permits operation of all product features (including maintenance of

network connectivity), albeit with a possible delay to transition into print-ready or production mode.

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3.9
print-ready mode

period when a printing machine is switched on with all assembled components (pre- and post-

processing units) prepared to deliver outputs in the shortest time after a print order is given, compared

with other waiting modes, such as sleep mode or off mode
3.10
production print mode
steady production print mode
period when a printing machine is printing live jobs

Note 1 to entry: A production print mode is characterized by a stable power consumption, when the printing

machine is printing in a representative and typical fashion.
3.11
RIP
raster image processor which converts data into a raster bit stream or bitmap
3.12
machine combination

software, hardware and print media which has a direct influence on the resulting print image quality

EXAMPLE Best-quality combination = device configuration (hardware) + substrate (media) + print mode

(software).

Note 1 to entry: RIP and print mode settings are examples of machine combination.

Note 2 to entry: When the settings depend heavily on the RIP and printing technology, the machine combination

can also be referred to as the digital printing combination.
3.13
device configuration
physical hardware equipment included in a given production line
[SOURCE: ISO 20690:2018, 3.14]
3.14
basic device configuration

standard hardware equipment configuration as defined by the manufacturer, owner or user of the

device for the type of printed products or market for which the press is being used

3.15
alternative device configuration
physical hardware configuration differing from the basic device configuration
[SOURCE: ISO 20690:2018,3.16]
3.16
print mode

collection of settings, that are used to control a given device configuration via software (RIP) to enable,

disable or otherwise influence the operation of that device

EXAMPLE Using four colours on a machine capable of seven colours, varying the resolution, changing the

speed or enabling duplex printing.
3.17
alternative print mode

collection of settings different from the print modes used for obtaining the best-quality or best-

productivity combinations and used for defining additional combinations
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3.18
imposition

fitting of test images (with no change to size) into the screen, sheet or unit length without overlapping

[SOURCE: ISO 20690:2018, 3.19]
3.19
imposition rate

ratio between the area of the imposed test images and the total area of the screen, sheet or unit

length paper

Note 1 to entry: In this document, the imposition rate is used to calculate the equivalent A4 or Letter pages

printed on larger paper formats, regardless of the original image size.
[SOURCE: ISO 20690:2018, 3.20]
3.20
nominal energy efficiency
nom

number of printed equivalent A4 pages or m per kWh, measured in cruising state of production print

mode, excluding the first page

Note 1 to entry: The number of output pages and the corresponding integral power are measured over the

specified time.
3.21
effective energy efficiency
eff

number of printed equivalent A4 pages or m per kWh, whose energy covers not only production print

mode but also other relevant modes, such as print-ready, sleep, transitional and maintenance modes

3.22
transitional mode
start-up mode

period connecting two stable modes with different average power consumptions, i.e. “off mode and print-

ready mode”, “sleep mode and print-ready mode” and “print-ready mode and production print mode”

3.23
maintenance mode

period required to maintain quality of devices, conducted regularly, for example prior to starting

production print
3.24
first page print time
FPPT

number of seconds or minutes between the initiation of the job and the completion of the first cut sheet

print or the completion of the first unit-page print imposed across the width of roll paper

Note 1 to entry: FPPT is measured from a stable condition of the relevant mode. For example, print-ready mode

after the completion of a previous job may need a considerable time to stabilize because the heating unit needs

several minutes for cooling to a stable, ready condition. If FPPT were measured before cooling off, the measured

value could be shorter than that measured from a stable print-ready state, creating inconsistencies.

Note 2 to entry: In small format devices, FPPT is known as “first print out time” (FPOT). See ISO/IEC 17629:2014.

3.25
warm-up time

time required by the printing device to warm up from off mode, given by the difference in FPPT between

off mode and print-ready mode
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3.26
recovery time

time required by the printing device to recover from sleep mode given by the difference in FPPT between

sleep mode and print-ready mode
3.27
copy
test form printed on a substrate regardless of being printed simplex or duplex

EXAMPLE 100 copies = 100 test forms printed on 100 sheets (simplex) or 50 sheets (duplex) or 100 images of

the test form imposed on the given substrate.
3.28
consistency check

method for determining the stability and validity of two sequential measurements before averaging

the results

EXAMPLE “5 % consistency” is satisfied when the first result value A and the second result value B meet

0,95 ≤ 2A / (A + B) ≤ 1,05, where result value means reporting value (e.g. XX pages/kWh for “energy efficiency”).

3.29
image quality adjustment

modifications made during printing to ensure print image quality that forces the printing system to

pause production for a short period of time

Note 1 to entry: Image quality adjustments depend on many parameters such as test form area coverage or

required quality level.

Note 2 to entry: Some printing devices will make image quality adjustments during printing to ensure print

quality, where the devices continue moving without delivering any printouts.
3.30
unit under test
UUT
the digital printing device which is being measured
3.31
dummy print
preliminary job conducted in order to bring the UUT to print-ready mode
3.32
trailing edge

ridge line of printed cut sheet or imposed image form on roll paper, situated at the end along the

transportation direction
3.33
job structure

typical work flow of the printing press per period (e.g. day) with power consumption levels along

sequential modes
3.34
tonal coverage
cumulative colourant percentage

EXAMPLE A full sheet of 100 % deep black in CMYK has a tonal coverage = “400”. The colourant coverage is

defined by the tone value as specified in ISO 12647-1.

Note 1 to entry: Typical coverage based on one colour plane are: light — 1 % to 9 %, medium — 10 % to 35 %,

heavy — 36 % above.
[11]
[SOURCE: XJDF-Specification-2.0 Draft 2017-05-11 ]
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4 General conditions
4.1 Condition, age and machine configuration

How much power a digital printing device and peripheral devices uses is subject to many influences

such as the selected print mode, equipment characteristics and their condition, ambient conditions,

selected print speed, additional machine settings and the printing substrates used, especially their

drying requirements.

The operational climate should comply with the following conditions and the actual conditions shall be

documented:
— temperature: 20 °C–25 °C, and
— relative air humidity: 45 %–60 %.

Measurement of the operational climate parameters shall be made immediately before the start of the

power measurement at a distance of 1 m from the front side of the paper input, at a height of 1,60 m

above floor level.

The manufacturer, owner or user of a printing system shall determine a basic or standard device

configuration that can be used for testing the two required machine combinations, best-quality and

best-productivity. These two combinations shall be used for printing and measuring, to reflect the

influence of the digital press’s configuration on its power consumption and energy efficiency data.

— Best-quality (BQ) combination: The manufacturer, owner or user of a printing system shall select

a device configuration, print mode and substrate for achieving the best possible saleable print

quality. All colourants of the system shall be used.

— Best-productivity (BP) combination: The manufacturer, owner or user of a printing system shall

use the same device configuration as used in the best-quality combination with a print mode and

substrate for achieving the highest possible saleable productivity.

— Alternative (AL) combination: Using the same device configuration, alternative print modes

are allowed (e.g. monochrome printing of a colour test page on a colour device, printing with four

colours on a device capable of seven colours or changing the print resolution) and shall be reported

as an alternative combination so as not to be confused with the mandatory best-quality or best-

productivity combinations.

On a monochrome printing device, monochrome printing is not considered to be an AL combination and

is to be tested in both BQ and BP combinations, if possible.

Electrophotographic processes have significantly fewer parameters affecting energy efficiency than

inkjet printing. However, printing systems are available that allow for a change in print image quality,

for example by adding a further colourant. If the printing press to be evaluated does not allow for a

meaningful separation between BQ and BP, one machine configuration may be used. This machine

combination shall be labelled best-quality/best-productivity (BQ/BP).

AL device configurations may include additional pre- or post-handling or print and output enhancement

equipment (e.g. sheeting, folding, binding, seven colours, substrate enhancement or manipulation)

under the condition that the additional equipment is built in as part of the production line (in-line). Any

AL device configurations shall b
...

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