Xaar XJ128 Series User manual

Guide to Operation
XJ128
High Performance
Ink Jet Printhead
XJ128/200
XJ128/200 Plus
XJ128/360
XJ128 Guide to Operation
Xaar Document no D031010302 Version A
Xaar Confidential

XJ128 and XJ128 Plus Printhead
XJ128 Guide to Operation Xaar Document no: D031010302 Version A Page 1
XAAR
XJ128 Guide to Operation
_______________________________
Xaar
Science Park
Cambridge
CB4 OXR
United Kingdom
Phone [phone], Fax [phone]

XJ128 and XJ128 Plus Printhead
XJ128 Guide to Operation Xaar Document no: D031010302 Version A Page 2
Table of Contents
1Introduction....................................................................6
1.1 Overview ............................................................................................................................ 6
1.2 Safety instructions.............................................................................................................. 7
1.3 Disclaimer .......................................................................................................................... 7
2General Product Information .........................................8
2.1 The XJ128 printhead.......................................................................................................... 8
2.2 Xaar technology ................................................................................................................. 8
2.2.1 Xaar piezo technology................................................................................................... 8
2.3 Product handling and installation....................................................................................... 9
2.3.1 Anti-static precautions ................................................................................................... 9
2.3.2 Cleanliness.................................................................................................................... 9
2.3.3 Handling ........................................................................................................................ 9
2.3.4 Nozzle plate protective cap ........................................................................................... 9
2.3.5 Installation and pre-flushing........................................................................................... 9
2.3.6 “Hot-plugging”.............................................................................................................. 10
2.4 Storage and shipment...................................................................................................... 10
2.4.1 Storage conditions....................................................................................................... 10
2.4.2 Shipping conditions ..................................................................................................... 10
2.5 Product support................................................................................................................ 11
3Product Description.....................................................11
3.1 Parts description .............................................................................................................. 11
3.1.1 Actuator ....................................................................................................................... 11
3.1.2 Electrical connector ..................................................................................................... 11
3.1.3 Chassis........................................................................................................................ 11
3.1.4 Cover........................................................................................................................... 12
3.1.5 Driver chips.................................................................................................................. 12
3.1.6 Ink inlets and filter........................................................................................................ 12
3.1.7 Nozzle plate................................................................................................................. 12
3.1.7.1 XJ128/200 and XJ128/360................................................................................. 12
3.1.7.2 XJ128/200 Plus .................................................................................................. 12
3.1.8 Serial number .............................................................................................................. 12
3.2 Product specifications...................................................................................................... 13
3.2.1 Printhead life................................................................................................................ 14
4Mechanical Guide........................................................15
4.1 Channel numbering and side definition............................................................................ 15
4.2 Printhead mounting.......................................................................................................... 16
4.2.1 Printhead orientation ................................................................................................... 16

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4.2.2 Printhead datum locations........................................................................................... 16
4.2.3 Print distance............................................................................................................... 17
4.2.4 Angle of printhead relative to substrate....................................................................... 17
4.3 Thermal management...................................................................................................... 18
4.3.1 Printhead temperature................................................................................................. 18
4.4 Ink connection.................................................................................................................. 19
4.5 Mechanical system design............................................................................................... 21
4.5.1 Printhead shock and vibration ..................................................................................... 21
4.5.2 Printhead enclosure..................................................................................................... 21
4.5.3 Multiple printheads ...................................................................................................... 21
4.5.4 Substrate / media or printhead motion ........................................................................ 21
5Electrical Functions .....................................................22
5.1 Function overview ............................................................................................................ 22
5.2 Signal level definition ....................................................................................................... 23
5.3 Signal descriptions........................................................................................................... 24
5.4 Electrical connection to the printhead .............................................................................. 25
5.5 Grounding and isolation ................................................................................................... 26
6Electrical Specifications and Data...............................27
6.1 Electrical requirements..................................................................................................... 27
6.1.1 Absolute maximum electrical ratings........................................................................... 27
6.1.2 Power supply sequencing............................................................................................ 27
6.1.3 Recommended electrical operating conditions............................................................ 29
6.1.4 Temperature compensation......................................................................................... 30
6.2 Data structure................................................................................................................... 31
6.2.1 Configuration data structure........................................................................................ 31
6.2.2 Cycle order .................................................................................................................. 31
6.2.3 Phase triggering .......................................................................................................... 32
6.2.4 Print data structure ...................................................................................................... 32
6.3 Electrical system design................................................................................................... 35
6.3.1 Power supply and grounding connections................................................................... 35
6.3.2 Cable lengths and signals ........................................................................................... 36
6.3.3 ESD and EMC considerations..................................................................................... 36
7Ink Supply System Design...........................................37
7.1 Ink supply materials compatibility..................................................................................... 37
7.2 Ink preparation ................................................................................................................. 37
7.2.1 Good ink ...................................................................................................................... 37
7.2.2 Ink filtration .................................................................................................................. 37
7.3 Providing a negative pressure ink supply......................................................................... 38
7.3.1 Gravity fed negative pressure ink supply..................................................................... 38
7.3.2 Vacuum fed negative pressure ink supply................................................................... 39
7.4 Ink supply system design................................................................................................. 39

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7.4.1 Small ink reservoir....................................................................................................... 40
7.4.2 Ink pump system.......................................................................................................... 40
7.4.3 System filter................................................................................................................. 40
7.4.4 Ink tubing..................................................................................................................... 40
7.5 Filling the printhead and supply system........................................................................... 40
7.5.1 Cleaning the ink supply system................................................................................... 40
7.5.2 Filling the printhead ..................................................................................................... 41
8Maintenance, Reliability and Lifetime..........................43
8.1 Printhead maintenance .................................................................................................... 43
8.1.1 Why printhead maintenance........................................................................................ 43
8.2 Maintenance strategies.................................................................................................... 43
8.2.1 Operational maintenance ............................................................................................ 43
8.2.2 Short-term maintenance.............................................................................................. 44
8.2.3 Long-term maintenance............................................................................................... 44
8.3 Printhead maintenance methods ..................................................................................... 44
8.3.1 Pressure purge............................................................................................................ 44
8.3.2 Vacuum purge ............................................................................................................. 45
8.3.3 Wiping.......................................................................................................................... 45
8.3.4 Vacuum wiping ............................................................................................................ 46
8.3.5 Blotting......................................................................................................................... 46
8.3.6 Ink Spitting................................................................................................................... 47
8.3.7 Capping ....................................................................................................................... 47
9Image Processing........................................................48
9.1 Image processing background......................................................................................... 48
9.1.1 File formats.................................................................................................................. 48
9.1.2 Image processing software.......................................................................................... 49
9.1.3 Colour spaces.............................................................................................................. 49
9.2 Processing an image........................................................................................................ 50
9.2.1 Process flow ................................................................................................................ 50
9.2.2 Resolution and sizing .................................................................................................. 51
9.2.3 Changing colour space................................................................................................ 52
9.2.4 Ink control.................................................................................................................... 52
9.2.5 Splitting ink channels................................................................................................... 53
9.2.6 Binary patterning methods........................................................................................... 54
9.2.7 Saving an image for printing........................................................................................ 55
9.2.8 XJ128 image transformation........................................................................................ 56
9.2.8.1 Printing angle and horizontal / vertical resolution ratios..................................... 56
9.2.8.2 Extraction of image data..................................................................................... 57
10Trouble Shooting.........................................................59
10.1 Printhead problems.......................................................................................................... 59
10.2 Returning printhead(s) to Xaar......................................................................................... 59

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11Feedback and Support................................................60
11.1 Feedback ......................................................................................................................... 60
11.2 Support............................................................................................................................. 60
Appendices......................................................................61
Appendix A, Environmental Considerations .................................................................................. 61
Recycling packaging materials.................................................................................................. 61
Recycling the printhead............................................................................................................. 61
Appendix B, Document History and Changes ............................................................................... 62
Revision history......................................................................................................................... 62
Document changes ................................................................................................................... 62
Appendix C, Patents, Trademarks and Product Marking............................................................... 63
Patents...................................................................................................................................... 63
Trademarks............................................................................................................................... 63
Product marking........................................................................................................................ 63
Copyright................................................................................................................................... 63
Safety standards ....................................................................................................................... 63
CE Compliance and working environment................................................................................ 64
Appendix D, Mechanical drawing .................................................................................................. 65
Appendix E, The Xaar flex-cable................................................................................................... 66
Glossary ..........................................................................67
Index................................................................................68

XJ128 and XJ128 Plus Printhead
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1 Introduction
1.1 Overview
This document is only valid for the Xaar XJ128 product. This document is provided to supply details
and information relating to the XJ128 printhead and it’s operation. The document will cover the
following sections:
 Introduction
 General Product Information
 Product Description
 Mechanical Guide
 Electrical Functions
 Electrical Specifications and Data
 Ink Supply System Design
 Maintenance, Reliability and Lifetime
 Image Processing
 Trouble Shooting
 Feedback and Support
 Appendices
This edition applies to the above product only and to all subsequent releases and modifications until
otherwise indicated in new editions. Changes are made occasionally to the information herein; any
such changes will be reported in subsequent revisions.
Note that the use of this symbol indicates that the text you are reading is critically
important and the instruction should be observed.
This document will make references to other Xaar documents, which should be used in conjunction
with this referenced material.
Please address any comments to:
Sales Engineering
Xaar plc
Science Park
Cambridge
CB4 OXR
United Kingdom

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1.2 Safety instructions
Although all efforts have been made to ensure that the XJ128 is safe for use, Xaar cannot be held
responsible for any incidents or injuries resulting from mishandling or misuse. It is important to
ensure that liquid does not come into contact with electrical areas and that appropriate safety
precautions are taken when using the XJ128 printhead.
1.3 Disclaimer
This manual is intended as a guide for the installation and use of the Xaar XJ128 printhead and the
contents are believed to be accurate at the time of compilation. Xaar assumes no liability for direct or
indirect damage or loss incurred due to errors, omissions, discrepancies or changes between the
equipment and it’s documentation and does not give any representation, condition or warranty
(whether express or implied, by law, custom or otherwise) as to its accuracy, completeness or
correctness, or its fitness for purpose, or that use of a device described herein or reproduction of the
contents will not infringe any rights of any third party or otherwise whatsoever, and the user agrees
that it has not relied on any. Information in this manual is intended for reference only. Equipment and
documentation is subject to change without notice.
In no circumstances shall Xaar have any liability whatsoever for any loss or damage, howsoever
arising, and whether direct, indirect, consequential, financial or otherwise in any way from any use of
or reliance placed on or otherwise in connection with the contents of this manual or use of a device
described herein. The foregoing shall not exclude any liability, which cannot by law be excluded.
No license, either expressed or implied or otherwise, is granted under any patents, copyrights or
other intellectual property rights of Xaar.
No part of this document may be copied or reproduced in any form or by any means without the prior
written consent of Xaar.

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2 General Product Information
2.1 The XJ128 printhead
The XJ128 inkjet printhead consists of a piezo based, 128-channel actuator with ink-supply filter and
drive circuitry mounted on a metallic chassis. The printhead is available in three different models.
Each model operates in a ‘binary’mode, thus ejecting a single sized drop upon demand.
2.2 Xaar technology
As with all Xaar technology products the
printhead utilises Xaar’s patented shear
mode, shared wall piezo based
technology.
2.2.1 Xaar piezo technology
Xaar’s printhead technology is based upon a piezo ceramic material (PZT). When a voltage is
applied across this material the material distorts or bends. Xaar uses this phenomenon by machining
rows of parallel channels into a PZT block. An electrode is then placed onto the sides of the channel
walls allowing a voltage to be applied across it. The way in which Xaar makes the wall bend due to
the applied voltage is known as “shear mode.”Two channels share the wall, and hence the term
“shared wall.”
These channels are filled with ink and a pressure wave inside the ink is generated due to the
distortion of the PZT walls. This pressure wave forces ink out of the end of the channels via the
printheads nozzle.

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2.3 Product handling and installation
2.3.1 Anti-static precautions
Xaar printheads are static sensitive devices, which can be damaged if they are touched
without the necessary precautions being taken.
Xaar printheads are supplied in antistatic packaging. These should only be opened and handled in
an anti-static or electrostatic protected area (EPA). Unpacking and handling of the printheads should
be performed with the correct electrostatic discharge (ESD) precautions such as a grounded wrist
strap and conductive work mat.
2.3.2 Cleanliness
Xaar printheads are precision devices and should be treated as such. It is essential to
carry out all installation and development in as clean an environment as possible.
2.3.3 Handling
The nozzle plate on the printhead is sensitive to handling. On two models of the XJ128
printhead, the nozzle plate has a special coating, called a non-wetting coating (NWC).
This keeps the nozzle plate free of excess ink. Contact with this surface must be
avoided to prevent damage to this coating. Damage to this coating can cause a
reduction in the performance of the printhead. With all models of the XJ128 printhead,
contact with the nozzle plate surface must be minimised to avoid damage to the nozzle
plate.
2.3.4 Nozzle plate protective cap
The nozzle plate is protected during shipment by a plastic protective guard. This must
be carefully taken off prior to the printhead being filled with ink.
2.3.5 Installation and pre-flushing
The XJ128 printhead is supplied having been through a series of printing tests as part
of the manufacture. There will be some residual print test fluid within the printhead. In
some cases, the residual fluid will be incompatible with the ink to be used with the
printhead. In such cases, the printhead will require additional pre-flushing using
approved flushing fluids and procedures. These will be ink specific and are detailed in
the corresponding Ink and Printhead User Guide.

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2.3.6 “Hot-plugging”
The XJ128 printhead must not be connected or disconnected to the electrical supply
whilst the power is on. This is known as “hot-plugging”and will cause damage to the
printhead.
2.4 Storage and shipment
2.4.1 Storage conditions
 Air Temperature -15oC to 60oC
 Humidity 10% to 90% RH non-condensing
The XJ128 printhead should not be stored outside of its original packaging. It is recommended that
the printhead be stored in its packaging until required and that installation time is kept to a minimum.
Should a printhead be removed from an application, the printhead should be flushed clean of ink with
the appropriate Xaar cleaning solution. The cleaning solution should then be purged out of the
printhead with clean, dry filtered air. This process is detailed in the Ink and Printhead User Guide
documentation. Once clean the printhead should be stored in it’s packaging. If the original packaging
is not available a clean, opaque, ESD proof bag will suffice.
2.4.2 Shipping conditions
In conjunction with the unopened packaging as provided by Xaar, the XJ128 printhead has been
tested to withstand the following shipping conditions. Storage and/or shipment of the products
outside of these conditions can void any claim for warranty on the printhead.
The XJ128 printhead has passed tests according to standard ETSI EN 300 019-2-2 Transportation,
Class 2.3, 1999-09
Description Detail
Vibration X, Y and Z axis 5-20 Hz, -3dB/oct, 0.78 gRMS, 30 mins
Bump X, Y and Z axis 18g, 6 ms, half sine, 100 bumps
Drop Test One flat drop towards each side Height 1.0 m
Temperature Minimum -15oC
Maximum 60oC
Humidity 8 to 80%RH non-condensing
Table 2.1- Shipping conditions

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2.5 Product support
Support for all Xaar products is available from Xaar. Please contact your regional office for further
information. Please refer to section 11 for details.
3 Product Description
The product description detailed in the next section provides a brief overview of the main
components that make up the XJ128 printhead. Greater detail is given in later sections of this
document.
3.1 Parts description
The XJ128 printhead is built up from the following basic components as shown in figure 3.1.
Figure 3.1 - Isometric views of the XJ128 printhead
3.1.1 Actuator
The actuator (not visible in figure 3.1) is located behind the nozzle plate and is the active element of
the printhead. The actuator consists of an array of ink channels, which are sawn into a piezo-ceramic
material. The actuator converts the electrical energy into a pressure wave necessary to eject drops
of ink.
3.1.2 Electrical connector
Interface to the outside user electronics.
3.1.3 Chassis
This is the mounting base for the mechanical assembly. The chassis has datum areas to provide
location of the printhead in a mechanical assembly. The chassis is thermally connected to the driver
electronics and is used to dissipate or provide heat to the printhead.
Nozzle plate
Cover
Coloured Insulator
Serial number
Electrical
connector
Ink inlet port
Chassis

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3.1.4 Cover
A plastic cover to protect the actuator and electronic circuitry, including ink filter and internal ink path.
The cover must not be removed or tampered with. Any attempt to do so will invalidate the printhead
warranty.
3.1.5 Coloured insulator
The coloured insulator indicates the model of the printhead, for example XJ128/200, XJ128/360 or
XJ128/200 Plus. The colours and associated models are detailed in Table 3.1
3.1.6 Driver chips
The driver chips (not shown in figure 3.1) store and control the information for the ‘firing’pulses to be
sent to the actuator.
3.1.7 Ink inlets and filter
The XJ128 printhead has a single ink inlet port. The ink inlet is the point at which the ink connection
is made to the printheads. The printhead is fitted with a filter (not shown in figure 3.1) to protect the
actuator and nozzles from contamination. It is made of a 15µm stainless steel mesh. This is the final
filter acting as a complement to the filter in the ink delivery system. For maximum life, staged filtering
is essential, with the OEM incorporating a primary filter in their design. See section 7 for details.
3.1.8 Nozzle plate
Depending upon the model of the XJ128 printhead, the nozzle plate properties differ. In both cases,
the nozzle plate is the plastic film into which the nozzles are formed. Depending upon the printhead
model used, different ink system and maintenance strategies must be adopted. These are detailed in
sections 7 and 8 of this document.
3.1.8.1 XJ128/200 and XJ128/360
The standard XJ128/200 and XJ128/360 nozzle plate is coated with a special non-wetting coating
(NWC). This helps to keep the nozzle plate clear of ink around the nozzle orifices.
3.1.8.2 XJ128/200 Plus
The XJ128/200 Plus printhead utilises a ‘wetting’nozzle plate. This means that a thin film of ink is
required on the surface of the nozzle plate at all times to ensure reliable and high quality printing is
achieved.
3.1.9 Serial number
The printhead serial number is marked on the rear of the printhead as shown in figure 3.1

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3.2 Product specifications
The specification in table 3.1 details the performance of the each printhead model, as tested under
standard operational conditions. These specifications can vary according to printhead integration and
system set-up.
The specifications listed in table 3.1 are based upon testing carried out by Xaar under
laboratory conditions with approved inks. In a customer application, some
specifications such as linear speed, resolution and throughput, together with the final
print quality and machine output, will be subject to the design of the machine and the
number of passes required to achieve the print quality and coverage desired. The
choice of ink and substrate/media used will also ultimately impact the printhead
performance.
Description XJ128/200 XJ128/360 XJ128/200
Plus Unit
Colour of insulator Blue Black Purple -
Nozzle plate Non-wetting Non-wetting Wetting -
Active nozzles 128 -
Nozzle pitch 137.1 m
Nozzle diameter 50 35 50 m
Nominal drop volume180 40 70 pl
Drop velocity25.0 6.0 5.0 m/s
Maximum drop deviation 1.8 1.0 1.8 degrees
Ambient temperature range 10 to 40 10 to 40 10 to 40 oC
Ambient humidity range (non condensing) 10 to 80 RH 10 to 80 RH 10 to 80 RH %
Maximum frequency 4.25 5.55 5.55 kHz
Maximum linear speed 540 390 705 mm/s
Pixel resolution (single pass)3200 x 200 360 x 360 200 x 200 dpi
Print width416.5 9.0 16.5 mm
Printhead weight (dry) 15.5 15.5 15.5 g
Dimensions (W x D x H) 37.2 x 40.8 x 11.3 mm
Recommended printing distance51.0 mm
Maximum printhead acceleration 39.24
4 m/s2 g
Table 3.1 - Product specifications
1Drop volume is frequency, ink and system dependant.
2Drop velocity is ink and system dependant.
3At specified printhead angle.
4At specified print resolution.
5Print distance specified is from nozzle plate. Print quality beyond that distance recommended, will vary.

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3.2.1 Printhead life
The printhead is capable of performing up to and beyond 4 billion (4x109) drops within an approved
system utilising approved ink. This is a typical figure and subject to the use of a successful printhead
maintenance system.
Printhead life and performance is dependant on several key factors.
 Materials compatibility of ink and system components.
 Quality of printhead maintenance
 System design and environmental conditions.
Although this document does not cover these factors extensively, many of these issues can be
discussed with your local sales engineering representative, who can provide further details and
guidance to help printhead integration.

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4 Mechanical Guide
Before beginning a design phase with Xaar printheads, please ensure that you have obtained the
latest printhead drawings from Xaar Sales Engineering. See section 11 of this document for further
information.
4.1 Channel numbering and side definition
Looking directly at the nozzle plate on the printhead, with the nozzles pointing towards you and the
ink inlet pointing away from you, nozzle 1 is on the right side of the printhead.
“Top”means position closest to cover side.
“Bottom”means position closest to chassis side.
Figure 4.1 - Printhead side definition
There are a total of 134 nozzles viewable on the nozzle plate. The active nozzles are numbered 1 to
128. Nozzle 1 is referenced to the datum features on the printhead. Adjacent to nozzle 1 are 4
“guard”or “dummy”nozzles. These are shown in figure 4.3. Adjacent to nozzle 128 are 2 “dummy”
nozzles. All dummy nozzles are non functional and cannot be activated. When looking towards the
nozzle plate, on the printhead, the nozzles are numbered from right to left, as shown in figure 4.1.
Left side
Right side
Back side
Front
Top side
Dummy
nozzles
Dummy
nozzles
Print nozzle #128 (last)
Print nozzle #1 (first)

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4.2 Printhead mounting
The printhead must be treated with care. The most delicate part of the printhead is the
nozzle plate. Avoid contact with the nozzle plate at all times.
Note that all loads on connectors, tubes and cables should be relieved.
4.2.1 Printhead orientation
There are three primary orientations for mounting the XJ128 printhead, as shown in figure 4.2.
1. With the nozzle line horizontal, and the metal chassis down (XaarJet logo facing up), figure
4.2a.
2. With the printhead firing down (Connector facing up), shown in figure 4.2b.
3. With the nozzle line vertical or close to vertical and ink inlet from beneath. This is the best
orientation for easiest filling of the printhead with ink, as shown in figure 4.2c.
Positions set between the three primary orientations are also achievable, as indicated in figure 4.2.
Figure 4.2 - Printhead orientations
4.2.2 Printhead datum locations
The printhead chassis has three datum references with approximate reference dimensions to the first
firing nozzle in the printhead. These should be used as a guide to aid quick and easy mounting and
alignment of the printhead into appropriate mounting systems.
The mechanical drawing in Appendix D has details of the reference dimensions. The datums are
shown in figure 4.3.
Fig.4.2a
Fig.4.2b
Fig.4.2c

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Figure 4.3 - Datum reference to 1st firing nozzle
4.2.3 Print distance
The recommended printing distance between the media or
substrate surface and the printhead nozzle plate is shown in figure
4.4.
Greater distances will significantly reduce the print
quality of the image. The effect of ‘satellite drop’
formation is increased significantly at high print
distances, reducing overall print quality.
A consistent print distant must be maintained during
operation to ensure optimal print quality.
Figure 4.4 - Print distance
4.2.4 Angle of printhead relative to substrate
The XJ128 printhead is designed to be mounted at an angle, relative to the substrate, to achieve the
desired printing resolution. Mounting the printhead at a more acute angle results in a higher vertical
printing resolution.
DATUM A
DATUM
FACE C
REF
REF
1
st
Firing Nozzle
Dummy nozzles
DATUM B
1.0 mm
Substrate/Media

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The horizontal printing resolution is driven by the firing frequency and the speed of the printhead
relative to the substrate. However, for a given vertical resolution the horizontal resolutions are
restricted. This restriction is a consequence of the nozzle divided into three different phases, with the
fire of each phase separated by a fixed period.
As an example, for ‘single-pass’printing6, the XJ128 printhead should be angled relative to the
substrate as shown in figure 4.5, in order to achieve the desired print resolution of 200 x 200dpi for
the XJ128/200 or XJ128/200 Plus printhead, or 360 x 360dpi using the XJ128/360 printhead.
Failure to angle the printhead and correctly process the image to be printed may result in a ‘saw
tooth’effect caused by the A-B-C firing sequence.
Figure 4.5 - Angled printheads for printing at specified resolution
4.3 Thermal management
The absolute maximum temperature of the printhead must not exceed 55oC. If the
printhead exceeds this temperature, permanent damage can occur.
4.3.1 Printhead temperature
Temperature control of the printhead is important to ensure reliable operation. Printheads produce
heat when powered, whether printing or idling. It is essential that heat management be considered
when installing the printhead in order to obtain optimum performance and reliability.
Please refer to the Ink and Printhead User Guide for the recommended operational temperature or
temperature range of the printhead for the specified ink.
6‘Single-pass’printing based upon testing using oil-based inks on porous substrates
XJ128/200 and XJ128/200 Plus
Print swathe
16.5mm
Print swathe
9.0mm
XJ128/360
31.0 deg
71.6 deg

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The operational temperature of the printhead will be controlled by several factors:
 Thermal paths arising from the way the printhead is mounted (heat sinking)
 Thermal paths in the application (mechanical and liquid)
 The type of ink used
 Internal heat generation (electronics etc)
 Environmental heat dissipation
The maximum heat dissipation to be removed from the XJ128 printhead is 6 Watts. A typical value
for heat dissipation to be removed from the XJ128 printhead is 1 to 2 Watts, in normal operation.
The most effective way of removing heat from the printhead is through the thermally
conductive aluminium chassis. This should be used to ‘cool’the printheads during
operation by removing heat generated by the printheads through a mechanical interface
with a heat sink.
4.4 Ink connection
Ensure that clean ink connectors are used. Ink connections to the printhead should be
prompt to reduce risk of contamination. Only use approved inks and associated
cleaning solutions available from Xaar.
Figure 4.6 –XJ128 ink inlet
The ink connection to the printhead is through the ink inlet port as shown in figure 4.6. Push a 3.0mm
ID tube over the ink inlet port. A flexible-type of tubing should be used, as an interference fit is
required. The ink inlet port has an OD of 3.1mm. This is also shown on the mechanical drawing in
Appendix D. A 4mm OD/3mm ID tubing is recommended when supplying ink to the XJ128 printhead.
Ink inlet