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

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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.