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 2018
© ISO 2018
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ii © ISO 2018 – All rights reserved

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
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

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.
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

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
E
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:
t2
Eu=×ti tdt
() ()
∫
t1
where u(t) and i(t) are the instantaneous values of voltage and current.
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
P
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
T
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

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
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
E
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
E
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

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 ]
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

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;
— paper delivery unit;
— external cooling units that can be directly attributed to the printing system;
— digital front end (RIP); and
— viewing cabinet.
All units that are required for printing but that can’t be attributed directly to the printing press (e.g.
a centralized pressure, air conditioning or cooling system) shall be estimated using averaged power
consumption values provided by the manufacturer. The method used shall be reported.
For units which can be directly attributed but for which power consumption varies with outside
temperatures, the actual temperature shall be reported. The average annual energy consumption based
on an average temperature of 10 °C and 20 °C should also be reported.
EXAMPLE A chiller or air conditioning unit mounted on the roof of a printing site might be connected
directly or indirectly to a press, but its power consumption relies on the outside temperature. Although for an
outside temperature of about 30 °C the device is constantly in operation, it might run only a fraction of the time
when the outside temperature is 10 °C or less. In order to account for this effect, the power consumption can be
estimated for two temperatures that represent different (cooler or warmer) climates. To accomplish this, one
would conduct power measurements or deduce the power based on the manufacturer data sheet provided for
temperatures around 10 °C and 20 °C. When performing power measurements, the recommended measurement
time is at least 1 hour.
4.3 Printing conditions and operational modes
4.3.1 General
The printing conditions, including the substrate used, shall be based on the machines’ BQ and BP
combinations and may also cover AL machine combinations. All combinations should be documented in
conformance with Annex A (measurement data sheet).
For printing, an unscaled one-page PDF test form shall be used. Any image can be used for the power
consumption measurement, as long as its contents represent practical commercial images with an area
coverage up to 40 % per channel, calculated by using tone value data as defined in ISO 12647-1. It is
advisable to use recognized test forms, such as that in ISO/IEC 24734:2014, B.2. The PDF file for the test
form shall be in A4, Letter or A3 format. The test form used shall be documented by means of a PDF file
of the printed image alongside the measurement data sheet.
Two-sided printing (duplex) may also be used. When two-sided printing is used, the same image shall
be printed on both sides of the sheet and the printed pages shall be included in the calculation of the
printed area or number of pages.
Large format presses, including those designed to accommodate continuous-form media greater than
[9]
or equal to 406 mm wide, are designed for A2 media and larger . Duplex printing may be used by
means of the optional print modes or accessories and the associated reporting shall cover this in an
unambiguous manner. For large format presses the pages shall be imposed to fill at least 66 % of the
total available substrate width. The imposition rate will be taken into consideration, see 4.6.
For small- and large-format printing, unless it can be reliably demonstrated that the consistency criteria
can be met in a shorter time, the continuous printing measurement time shall be at least five minutes.
In any event the measurement time shall not be less than one minute.
NOTE When a measurement time shorter than five min satisfies consistency criteria and gives the same
result as the five-min measurement, the shorter time measurement is considered to be reliable.
The print modes described in this clause shall be identified for the printing system to be tested and
the energy consumed for all existing modes shall be reported. Transitions between modes shall be
measured and reported.
4.3.2 Measurements referred to in ISO 20690 as well as in this document
4.3.2.1 General
The measurement of operational power consumption for this document should be consistent with the
principles of measurement as outlined in ISO 20690:2018, Annex B.
4.3.2.2 Off
The printer is connected to the power supply but is switched off.
In some cases, power is used even when the printer is switched off, for example for a heater. The power
used in this mode may be significant in cases where the printer is switched off overnight. The average
power (kW) consumed in this mode shall be measured and reported.
4.3.2.3 Sleep
A low-power mode where the printer can initiate printing corresponding to print requests, albeit with
a possible delay.
This mode is measured so that users will know whether it is important to turn the printer off when it is
not being used for a long time.
Where a sleep mode is supported by the press, the average power (kW) consumed in this mode shall be
measured and reported.
Where a sleep mode is not supported the report shall indicate this.
4.3.2.4 Print-ready
The printer is ready to print but printing has not yet started.
For many users the printer may spend a significant proportion of its time in this mode. The average
power (kW) consumed in this mode shall be measured and reported.
4.3.2.5 Production print (BQ)
The printing mode selected by the manufacturer or user of the UUT for use when highest-quality
printing is required.
The average of two measurements of the nominal energy efficiency during printing (A4 pages or m per
kWh) shall be measured and reported.
4.3.2.6 Production print (BP)
The printing mode selected by the manufacturer or user of the UUT for use when acceptable print
quality is required at high speed.
The average of two measurements of the E (A4 pages or m per kWh) shall be measured and reported.
nom
8 © ISO 2018 – All rights reserved

4.3.3 Additional measurements required for this document to estimate comprehensive energy
consumption
4.3.3.1 Maintenance
Many printer manufacturers recommend that day-to-day maintenance tasks are performed, such as
quality check, calibration, replacing element and wiping. In some cases, these tasks consume significant
energy and so may be important when calculating effective energy efficiency, reflecting comprehensive
energy consumption.
Where the manufacturer recommends routine maintenance operations, the energy (kWh) consumed
for each operation shall be measured and reported.
The frequency with which each maintenance operation is required to be performed, for example for
each print run, daily or weekly, shall be reported.
4.3.3.2 Transition from off to print-ready
The press shall be turned on and a page (or set of pages) printed as described in 4.5.3.2.2.
The energy E (expressed with Wh, as the amounts are small) consumed over the period from turning
on the printer until the printer is ready for printing shall be measured and reported, along with warm-
up time, namely the time from turning the press on to when the printer is ready.
The power consumed for this transition is measured so that users can decide when it is more cost-
effective to switch the printer off.
4.3.3.3 Transition from sleep to print-ready
When the press is in sleep mode, a page (or set of pages) shall be printed as described in 4.5.3.2.3 and
the energy E (expressed with Wh, as the amounts are small) consumed over the period from making
the print request until the UUT reaches print-ready shall be measured and reported. Recovery time,
namely the time measured from making the print request to print-ready shall be reported.
The power consumed for this transition is measured so that users can decide when it is more cost-
effective to switch the printer off.
4.3.3.4 Transition from print-ready to FPPT
When the press is in print ready mode, a page (or set of pages) shall be printed as described in 4.5.3.2.1
and the total energy (expressed with Wh, as the amounts are small) consumed over the period from
making the print request until the FPPT shall be measured and reported. The time from making the
print request to FPPT shall be reported.
In cases where the printer is used for many jobs with short run-lengths, the energy used in this mode
may be significant.
4.4 Measuring conditions
The power meters shall fulfil the following requirements:
— type: power line analyser with data logging capacity;
— measurement parameters: voltage, current;
[10]
— accuracy: ±3 % .
The measurement device type, model and age shall be documented. Valid test or calibration certificates
shall be reported. The power meter shall measure voltage and current to compute the active power (P).
The active power shall not be calculated by tabulated power factors or power consumption values.
The internal sampling rate of the measuring device for the current and voltage values shall be 5 kHz or
higher. The recording frequency shall be one second or less and the power consumption over time shall
be reported.
NOTE A threshold of 5 kHz is commonly used in the industry since the bandwidth captures deviation from
non-sinusoidal waveforms. 5 kHz is a common international practice for this purpose. The above requirements to
measure voltage and current are to ensure that hand-held power clamp meters are not used.
4.5 Test procedures
4.5.1 General
The following procedures are based on typical modes of digital printing devices such as off, sleep,
print- ready, production print (BQ) and production print (BP). Some digital printing devices may not
implement all designated modes. In such cases, only the existing modes shall be tested.
The UUT shall acclimatize to room temperature according to the manufacturer’s recommendations. If
no information is available, the UUT shall acclimatize for 1 h or more before the commencement of
power measurement testing. The duration of the acclimatization (h) shall be reported.
For power measurement, the test duration time as well as the power sampling time is specified for
relevant modes.
Power measurement of any production print modes shall be repeated at least twice. For other print
waiting and transitional modes, one power measurement test is sufficient.
The test file shall be suitable for printing on the output paper size without scaling or cropping. The test
file used for the test run shall be reported.
For large-format printing devices, A4, Letter or A3 test images shall be imposed for output. The ratio
of image area to large-format output area, namely the imposition rate, shall be reported along with
production measures (power consumption, productivity, energy efficiencies). The imposition rate is a
part of the testing condition, as determined by the layout of test images and not the inherent parameter
attributable to the UUT.
4.5.2 Power measurement for production print mode
4.5.2.1 Job definition for production print
Job length shall correspond to at least 5 min of continuous printing. The actual measurement time (min)
shall be reported. If image quality adjustment procedures take place during the measurement cycle,
they shall be part of the evaluation and reported.
For large-format devices, the output area corresponding to at least 5 min of continuous printing includes
plural A4/Letter images according to the imposition rate.
Print settings shall be selected according to BQ and BP combinations.
For digital printing devices whose BQ or BP distinction is ambiguous, a single representative machine
combination may be used. As a single representative machine combination, default setting (i.e. as
shipped) is recommended. If a setting other than default is used, the difference should be reported.
AL machine combinations are allowed (for example for print service providers interested in specific
process variations, such as drying). AL machine combinations are handled (measured, evaluated and
reported) in the same manner as described for BQ and BP.
4.5.2.2 Power measurement for production print mode
1) Conduct a minimum job dummy print run so that the UUT is in print-ready mode.
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2) Wait 10 min before sending a print job to the UUT in print-ready mode and start recording time
(h) and energy (Wh). Stop recording once the final trailing edge of the total output has exited the
printing machine. This is the last page print time . If the UUT transits to sleep mode before
10 min, change the transition time to over 10 min. If it is not adjustable, wait the maximum time
instead of 10 min, which shall be reported.
3) Calculate the average power P (W) using energy E (Wh) and corresponding time Δt (h) between the
first page print time and the last page print time .
4) Calculate the continuous print productivity S (ppm) using number of output pages N corresponding
to Δt of 3).
5) Calculate the E (A4 1 000 pages/kWh) from the energy E (Wh) and number of output pages N
nom
corresponding to Δt of 3).
6) If the UUT is still in print-ready mode, then repeat 2) to 5). If the UUT might not be in print-ready
mode, then repeat 1) to 5).
7) Compare the two results of E .
nom
8) If the two E values satisfy 5 % consistency, then proceed to 12). See NOTE 1.
nom
9) If they fail to satisfy 5 % consistency and the UUT is still in print-ready mode, then repeat 2) to 5)
one more time. If the UUT might not be in print-ready mode, then repeat 1) to 5).
10) If the results of the second and the third tests satisfy 5 % consistency, adopt the second and the
third test results for the calculation of 12). The first test results shall not be used in the following
calculations of E but shall be used for comprehensive energy consumption calculation as
nom
5 %-inconsistent data. See NOTE 2.
11) If the results of the second and the third tests fail to satisfy 5 % consistency and the UUT is still in
print-ready mode, repeat 2) to 5) one more time to get the third and the fourth test results. If the
UUT might not be in print-ready mode, then repeat 1) to 5). Repeat this procedure at the maximum
of five times until the last two test results satisfy 5 % consistency, which shall be adopted for the
calculation of 12). If 5 % consistency is not satisfied even at the fifth run, all 5 %-inconsistent data
shall be reported and used for the comprehensive energy consumption calculation.
12) Averaging two results, P (W), S (ppm) and E (A4 1 000 pages/kWh) shall be determined.
nom
13) For 5 %-inconsistent data in 11), production print power P (W), S (ppm) and unstable nominal
energy efficiency (E ) shall be determined. This data, together with E values, will be used
unstable nom
to estimate comprehensive energy consumption.
14) Repeat 1) to 13) corresponding to BQ combination and BP combination. If both combin
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