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Life cycle assessment of an

inkjet print cartridge

Doug Pollock
manufacturing development engineer
Hewlett-Packard lnkjet Business Unit

Remi Coulon
technical project manager
Ecobalance. Inc.
Hewlett-Packards lnkjet Business Unit (HP IJBU) designs and manufactures inkjet print cartridges for a wide
variety of computer printers, plotters, facsimile machines and related equipment sold by Hewlett-Packard and
other companies. In September 1994, HP IJBU undertook a comprehensive life cycle assessment (LCA) of its
highest selling print cartridge. The project was conducted with the assistance of Ecobalance, Inc., the U.S. branch
of a worldwide LCA consulting firm. After six months of extensive work involving many of HPs primary suppliers
and over 100 HP people spread over the U.S., Europe, and Asia, the project was completed. To the authors
knowledge, this in-depth LCA of a consumable is one of the first in the computer industry. This paper covers the
reasons for undertaking the study, the project findings, and how this information is being used.

Over the life of an inkjet printer, the average user may go through 50 or more print cartridges. Because the mass
of cartridges, ink, and related packaging consumed may exceed that of the printer, inkjet cartridges are often
perceived to be one of the leading sources of waste associated with computer printing. In Europe, especially,
environmental concern over printer consumables can be a significant factor affecting purchasing habits.
Legislation, like Germanys Electronic Waste Law is also a concern for print cartridge manufacturers, since
cartridges are one of the few consumable electronic products. In the face of these challenges, design engineers
often ask specific questions about the environmental impacts of different materials and product designs. Historical
environmental efforts often focused on manufacturing waste, with occasional design improvements. The
environmental impacts of distribution, product usage, and end-of-life disposal have not been accurately quantified
for printer consumables. In the face of growing environmental concern and a lack of scientific data for making
decisions, HP IJBU chose to perform an LCA of its highest selling inkjet print cartridge. Specifically, the goals of
this project were to provide:

guidelines for future product research and development

an understanding of current product impacts to focus product stewardship efforts
resourceddata for external communication

LCA was also seen to fit well with one of HPs corporate objectives, creating products which are environmentally
sound throughout their life cycle.
Project Description
A detailed life cycle assessment involves three primary phases:


1) Inventory Analysis: modeling and quantifying material and energy flows

2) Impact Assessment: translating inventory flows into potential environmental impacts
3) Interpretation & Suggestions for Improvement: using the results to reduce impacts of products and

Before beginning the LCA, the project scope or system boundaries had to be chosen. Since the European Union
(EU) is the source of leading environmental regulation and consumer pressure, an inkjet cartridge sold in Europe
was chosen as the focus of this study. This entailed modeling cartridge production and distribution from HPs
Singapore facility, the source of most HP cartridges sold in Europe. Fig. 1 shows an exploded view of an inkjet
cartridge. The primary components are the ink, the pen body and plug which contain the ink, and the printhead.
0-7803-2950-3/96$5.000 1996 IEEE


The printhead consists of the orifice plate and silicon substrate which fire the ink and the flex circuit which provides
electrical connections to the printer. Fig. 2 is a simplified flowchart of the LCA system boundaries. The processes
of seven suppliers and hundreds of internal operations were analyzed. HP processes studied ranged from thin film
and plating to assembly, ink-fill, and final product packaging. HP manufacturing facilities operations such as deionized water production, nitrogen, pressurized air, vacuuim, and waste treatment systems were also analyzed and
modeled. At each step, data were gathered on all primary sources of energy, chemicals and materials consumed,
and wastes produced. Yield data and the packaging and shipping distances for all primary supplies were included.
Distribution from Singapore to Europe, as well as within tlhe EU was also thoroughly investigated and modeled.
Customer usage patterns and end-of-life product disposal practices for Europe were used. The data gathering
phase of the project lasted for over four months with mope than 1,100 processes modeled. A testimony to the
project thoroughness is the fact that 99.6% by mass of the total chemical and material inputs in inkjet
manufacturing were included in the LCA.
In order to achieve consistency, all data were normalized to a common functional unit. The unit chosen was the
portion of a cartridge corresponding to 100 printed pages with an average print coverage of 5% black ink. For
reasons of simplicity and because they are sold in lower volume, color cartridges were not considered in this study.
The functional unit of 100 pages corresponds to the averlage weekly printer usage of a typical business and homebusiness user. Based on the average life of the product we studied, 100 pages equates to approximately 15% of
the cartridge life span.
As the data from suppliers and HP were collected, Ecobalance processed the data to create a complex computer
model. Associated with each material, chemical, and uniit of energy consumed were upstream and downstream
flows. The upstream flows consisted of other materials and chemicals which ultimately led to natural resources
extracted from the earth. The downstream flows consisted of wastes or co-products (used wastes) as well as the
usable product. Ecobalance used their extensive materiel and process databases to convert all of the materials,
chemicals, and units of power consumed to physical inputs from and outputs to the environment. Inputs consisted
of such things as crude oil, natural gas, water, iron ore, hydrogen, sand, and NaCI. Outputs included air emissions
(CO2, CO, SOx,NO,, hydrocarbons, metals, etc.), water effluents (suspended and dissolved solids, sulfates,
nitrates, dissolved organics, chlorides, etc.) and solid wastes (mineral, ash, non-hazardous and hazardous, etc.).
In the end, all of the data on inkjet processes and materials were linked to over 200 basic environmental inputs
and outputs.
With the inventory analysis phase of the project completed, individual process areas could be compared based on
environmental inputs and outputs. For example, the distribution process (consisting of air transport from
Singapore to Europe and truck and air transport within Europe) could be compared to the end-of-life disposal
(landfill, incineration with some energy recovery) on the lbasis of energy consumed and individual air and water
pollutants. However, with more than 200 environmental flows, this type of comparison can be tedious. To provide
additional interpretation for material and energy flows, Ecobalance conducted an impact assessment. This
consisted of translating and aggregating the inputs and outputs into potential environmental impacts. Flows were
first classified based on their contribution to specific enviironmental issues such as global warming, ozone layer
depletion, acidification, and depletion of natural resources. Next, the specific contributions of the inputs and
outputs to environmental issues were evaluated. For ex,ample, greenhouse gases were weighted according to
their global warming potential (GWP), with the final index representing CO2 equivalency as the common unit. This
process resulted in four primary environmental indices:

greenhouse effect
atmospheric acidification
natural resources depletion
nutrification potential

The greenhouse effect index is based on a list of provisional best estimates for global warming potentials
provided by the Intergovernmental Panel on Climate Change (IPCC), a group of worldwide scientists addressing
climate change. The acidification index is calculated based on the potentially acidifying emissions of S02,NOx
and NH, and their potential to form H+ ions. All acidifying substances were normalized to SO;! equivalency to
maintain consistency and reach a common unit of comparison. The natural resources depletion index takes into
account consumption, known reserves, and annual production figures to come up with a measure reflecting

resource scarcity. Nutrification potential of a substance is calculated on the basis of its potential biomass
formation by the addition of mineral nutrients to the soil or water. The addition of mineral nutrients (N and P) in
large quantities generally results in undesirable shifts in ecological diversity (e.g., algae growth and death of fish).
Fig. 3 shows the profile of these environmental indices across the print cartridge life cycle. The life cycle phases
are defined as follows:
Printhead Manufacture: impacts associated with the printhead component of the cartridge (silicon wafer
fabrication, thin film processing and chemicals to form the inkjet circuitry, plating, wafer sawing, bonding,
manufacture of the flexible circuit which makes electrical contact with the printer)
Final Assembly: impacts associated with the assembly of the cartridge, as well as parts used in assembly
and final packaging (ink manufacture, plastic and metal production for cartridge pieces, assembly
equipment power, all materials used in packaging the final cartridge)
Distribution: impacts of finished product transport from factory to final dealer (air transport from
Singapore to Europe and ground and air transport to the various countries in Europe)
Use: print cartridge energy as well as the energy used by the printer to move the cartridge and paper
during the print operation (does not include the energy used by the printer during rest or paper impacts,
although these impacts are included for comparison later in this paper. The usage impacts due to printing
energy were found to be very small and are not shown in Fig. 3.)
End-of-Life: impacts of product disposal after use by the customer (landfill and incineration with some
energy recovery)

The end-of-life impacts were found to be relatively small based on the European country average used in this
study. Results would vary depending on regional waste disposal practices. The option of recycling was not
covered in this study. Most of the packaging materials could be easily recycled, given availability of paperboard,
paper, and polystyrene recycling. Recycling of the packaging materials would be expected to partially offset the
final assembly profile by producing an end-of-life credit.
One of the most valuable uses of LCA is the ability to compare various product and process scenarios. In this
LCA, a number of alternative scenarios were analyzed. One scenario compared new print cartridge packaging
(introduced in mid 1994) with the former style of packaging. The new packaging encloses the cartridge in a
polystyrene clam shell which is sealed in a plastic/foil pouch and put into a paperboard box with a small paper
insert. The old packaging used a much bulkier aluminum tub design to provide critical moisture retention for the
product. The packaging change was initiated largely for environmental reasons and resulted in a 35% reduction in
packaging mass and a doubling of shipping efficiency. It also yielded significant savings in manufacturing and
shipping costs. However, it was unknown how the environmental savings compared to other product and process
impacts. A second scenario which was investigated was ocean shipment of cartridges in lieu of air transport. The
impacts of ocean shipment are widely recognized as being less than those of air transport. How much shipping
could improve the distribution impacts relative to the entire environmental profile was unknown. Since changes in
transport are largely independent of product design, this seemed like a relatively simple and realistic alternative for
reducing impacts. A final scenario modeled a resin change for the plastic used in the cartridge housing. In this
scenario, the change from the current specialty engineering resin to a less expensive and lower performance resin
was analyzed.
Figure 4 shows the reduction in potential environmental impacts due to the three product scenarios studied. The
new packaging is shown to have a significant reduction in environmental impact, totaling more than 15% across
each of three environmental indices. Ocean shipment also significantly reduces the cartridge impacts and has
subsequently been implemented for many of HPs cartridge shipments from Singapore. Together, these two
changes reduce the resource depletion index by more than 1/3 and both the global warming and acidification
potential by approx. l/.Q.Theresin change would also lead to sizable environmental savings, but requires
significant engineering resources and product qualifications to implement.

Besides the impacts of the inkjet cartridge, it was clear that several other related impacts might also be significant.
Studying inkjet printing without considering impacts of the print medium seemed incomplete. Including the
impacts of paper production would help to put the other results in perspective. Printer energy usage during periods
of non-use was also considered. Even though HPs printers meet the EPA Energy Star criteria for energy savings,
the small power consumption of idle mode can be significant over time. With studies indicating that most users
leave their printers on even when not in use, a usage model was chosen with 80% of printers being left on seven
days per week, 24 hours per day and 20% of printers tuirned on five days per week, eight hours per day.
Concerning cartridge manufacturing, secondary impacts such as the steel and concrete used in the buildings and
the copper, steel, and aluminum used in making the automated inkjet assembly equipment were also taken into
account. In addition, the energy required for lighting, hleating, and air conditioning of the production building were
considered. Finally, the LCA included the impacts of eimployees commuting to the manufacturing facility. Since
data on Singapore commuting were unavailable, data from HP IJBUs Oregon site were used. With the average
employee commuted 21.2 miles round trip and approxiimately 3,000 employees driving to work each day, this
impact seemed important to include.
Fig. 5 shows the composite of environmental indices fair the primary impacts related to inkjet production and use.
It is interesting that the environmental costs of paper production and printer idle energy account for almost 95% of
all four primary indices. The impacts of the building and production equipment were found to be negligible.
Employee commuting, though small relative to paper and printer energy usage, was a significant factor compared
to the print cartridge life cycle. The impacts of commuting on a functional unit basis equated to 12% of the natural
resource depletion and 14% of the global warming potential of the entire cartridge life cycle. Not shown in Fig. 5 is
the fact that commuting also contributed 1.5 times as much carbon monoxide to the atmosphere as the inkjet
cartridge total.

The results of the inkjet LCA have provided several clear priorities for reducing environmental impacts. First and
foremost, the results show the importance of the printeir and paper environmental impacts. lnkjet printers with
double-sided printing would allow for significant environmental savings. This could be accomplished by
mechanical design changes to the paper feed mechanism of the printer. A simpler and quicker solution to this
problem would be software changes which would print (everyother page and then allow the user to reinsert the
stack of paper to print the remaining pages. [For those committed green computer users, this can currently be
done in most software programs by first printing the odld pages in descending order, rotating the stack of papers
180 degrees, reinserting them, and finally printing the even pages in ascending order.] The environmental costs of
paper production also need to be considered. Non-wood fibers may have lower impacts during the paper pulping
process, although a full life cycle assessment is needed to account for all impacts. In addition, inkjet inks need to
be formulated to perform well on recycled and alternative fiber papers. Continued focus is also needed on printer
electricity usage. One possible improvement would be to design a printer that turns itself off after a specified
period of non-use. Again, an obvious solution is for users to turn their printers off when not printing. This simple
act would save nearly half of the printer electricity impacts, an amount nearly equivalent to the impacts of the
entire cartridge life cycle! It is also important to develop printers that use no power when in the off mode (the
printer we studied uses 3 watts of power when turned olff).
This study also indicated priorities for reducing the environmental impact of inkjet cartridges. The change in
product packaging highlighted the important role of prolduct size and distribution energy compared to the total life
cycle costs. The analysis of ocean shipment demonstrated another key way to reduce overall impacts. The
detailed breakdown of process impacts (not included in this paper) have also provided a great deal of direction for
minimizing impacts in specific HP product and process areas. Much of this input will be valuable to engineers
designing future products and processes. The LCA alstopointed out a surprising conclusion that employee
commuting can have a significant environmental impact relative to the product they produce. More importantly,
this study demonstrated the feasibility and usefulness of conducting a thorough life cycle assessment of a
computer peripheral. Even though the project involved primary data collection at several HP locations and at
more than seven major suppliers, it was completed in six months. This is well within the range of the product
development time cycle. With more than 1,100 linked processes representing 99.6% of the total inputs consumed
in the product manufacturing, the integrity of the results is ensured. Furthermore, the database compiled during
this project now allows full LCAs of similar products to be done in much less time.

Fig. 1Exploded View of lnkjet Print Cartridge

Orifice Plate

Nuturul Resources

Silicon Wafer



L V L - -




Steel production

Intermediate Products Manufactunng

(Gases, Chemicals, Metals, etc )




tartridge Assembly

PE, PP, Polyester



3 L Y -

- -


Ink Container
Resin Production

Flex circuit

Cartndge Filling and












- Cardboard, Corrugated


Board & Paper Productioii


Incineration With
Enerby Recovery


Incineration Without
Heal Recobeq


Fig.2. Print Cartridge Life Cycle - System Boundaries


Fig. 3. lnkjet Print Cartridge: Life Cycle Profile of Selected Potential Environmental













Final Assembly



Fig. 4 lnkjet Print Cartridge: Changes in Potential Environmental Impacts Due to

Product/Prociess Scenarios

0Global Warming Potential



Acidification Potential


2 %

z- .-g







0 0


i =La

3 m
o n

2 s

LCA scenarios


Fig. 5. lnkjet Print Cartridge: Potential Environmental Impacts - Results Put in Perspective










Life Cycle