AU2004220745B2 - Modular printhead assembly with thermal expansion compensation - Google Patents

Modular printhead assembly with thermal expansion compensation Download PDF

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Publication number
AU2004220745B2
AU2004220745B2 AU2004220745A AU2004220745A AU2004220745B2 AU 2004220745 B2 AU2004220745 B2 AU 2004220745B2 AU 2004220745 A AU2004220745 A AU 2004220745A AU 2004220745 A AU2004220745 A AU 2004220745A AU 2004220745 B2 AU2004220745 B2 AU 2004220745B2
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AU
Australia
Prior art keywords
printhead
printhead assembly
support member
mounting
thermal expansion
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
AU2004220745A
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AU2004220745A1 (en
Inventor
Kia Silverbrook
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Memjet Technology Ltd
Original Assignee
Silverbrook Research Pty Ltd
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Filing date
Publication date
Priority to PCT/AU2001/000260 priority Critical patent/WO2001066357A1/en
Priority to AU4034301A priority patent/AU4034301A/en
Priority to AUPQ6111 priority
Application filed by Silverbrook Research Pty Ltd filed Critical Silverbrook Research Pty Ltd
Publication of AU2004220745A1 publication Critical patent/AU2004220745A1/en
Application granted granted Critical
Publication of AU2004220745B2 publication Critical patent/AU2004220745B2/en
Assigned to ZAMTEC LIMITED reassignment ZAMTEC LIMITED Request for Assignment Assignors: SILVERBROOK RESEARCH PTY LTD
Assigned to MEMJET TECHNOLOGY LIMITED reassignment MEMJET TECHNOLOGY LIMITED Request to Amend Deed and Register Assignors: ZAMTEC LIMITED
Application status is Ceased legal-status Critical
Anticipated expiration legal-status Critical

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Description

I

-1- SMODULAR PRINTHEAD ASSEMBLY WITH THERMAL EXPANSION O

COMPENSATION.

00 Field of the Invention The present invention relates to printers, and in particular to digital inkjet printers.

S 5 Co-Pending Applications.

Various methods, systems and apparatus relating to the present invention are disclosed in the following co-pending applications filed by the applicant or assignee of the present invention on 24 May 2000: PCT/AU00/00578 PCT/AU00/00579 PCT/AU00/00581 PCT/AU00/00580 PCT/AU00/00582 PCT/AU00/00587 PCT/AU00/00588 PCT/AU00/00589 PCT/AU00/00583 PCT/AU00/00593 PCT/AU00/00590 PCT/AU00/00591 PCT/AU00/00592 PCT/AU00/00584 PCT/AU00/00585 PCT/AU00/00586 PCT/AU00/00594 PCT/AU00/00595 PCT/AU00/00596 PCT/AU00/00597 PCT/AU00/00598 PCT/AU00/00516 PCT/AU00/00517 PCT/AU00/00511 Various methods, systems and apparatus relating to the present invention are disclosed in the following co-pending application, PCT/AU00/01445, filed by the applicant or assignee of the present invention on 27 November 2000. The disclosures of these copending applications are incorporated herein by cross-reference. Also incorporated by cross-reference are the disclosures of two co-filed PCT applications, PCT/AU01/00261 and PCT/AU01/00259 (deriving priority from Australian Provisional Patent Application No.

PQ6110 and PQ6158). Further incorporated are the disclosures of two co-pending PCT applications filed 6 March 2001, application numbers PCT/AUO1/00238 and PCT/AU01/00239, which derive their priority from Australian Provisional Patent Application nos. PQ6059 and PQ6058.

Background of the Invention Recently, inkjet printers have been developed which use printheads manufactured by micro-electro mechanical systems (MEMS) techniques. Such printheads have arrays of microscopic ink ejector nozzles formed in a silicon chip using MEMS manufacturing techniques. The invention will be described with particular reference to silicon printhead chips for digital inkjet printers wherein the nozzles, chambers and actuators of the chip are MJ125-AU formed using MEMS techniques. However, it will be appreciated that this is in no way restrictive and the invention may also be used in many other applications.

Silicon printhead chips are well suited for use in pagewidth printers having stationary printheads. These printhead chips extend the width of a page instead of traversing back and forth across the page, thereby increasing printing speeds. The probability of a production defect in an eight inch long chip is much higher than a one inch chip. The high defect rate translates into relatively high production and operating costs.

To reduce the production and operating costs of pagewidth printers, the printhead may be made up of a series of separate printhead modules mounted adjacent one another, each module having its own printhead chip. To ensure that there are no gaps or overlaps in the printing produced by adjacent printhead modules it is necessary to accurately align the modules after they have been mounted to a support beam. Once aligned, the printing from each module precisely abuts the printing from adjacent modules.

Unfortunately, the alignment of the printhead modules at ambient temperature will change when the support beam expands as it heats up to the temperature it maintains during operation.

Summary of the Invention Accordingly, the present invention provides a printhead assembly for an inkjet printer, the assembly comprising: an elongate support member for mounting in an inkjet printer body; and, two or more printhead modules mounted in series along the support member, the support member having a structural component for strengthening the member, and a mounting component for mounting the printhead modules; wherein, the mounting component is connected to the structural component to allow relative thermal expansion between the mounting component and the structural component, and wherein the printhead modules are positioned on the support member such that they align when the support member is at its operating temperature but not necessarily at other temperatures.

2a Conveniently, the support member may have a core of silicon and an outer metal shell. In a further preferred embodiment, the support member is adapted to allow limited relative movement between the silicon core and the metal shell. To achieve this, the support member may include an elastomeric layer interposed between the silicon core and metal shell. In other forms, the outer shell may be formed from laminated layers of at least two different metals.

0 It will be appreciated that this system requires the coefficient of thermal expansion of Sthe printhead chips to be greater than or equal to the coefficient of thermal expansion of the 0 beam, otherwise the "gaps" left between the printhead modules as compensation at ambient temperature will not close as the beam reaches the operating temperature.

Brief Description of the Drawing A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawing in which: N Figure 1 shows a schematic cross section of a printhead assembly according to the 0present invention.

to Detailed Description of Preferred Embodiments Referring to the figure the printhead assembly 1 has a plurality ofprinthead modules 2 mounted to a support member 3 in a printer (not shown). The printhead module includes a silicon printhead chip 4 in which the nozzles, chambers, and actuators are manufactured using MEMS techniques. Each printhead chip 4 has at least 1 fiducial (not shown) for aligning the printheads. Fiducials are reference markings placed on silicon chips and the like so that they may be accurately positioned using a microscope.

According to one embodiment of the invention, the printheads are aligned while the printer is operational and the assembly is at the printing temperature. If it is not possible to view the fiducial marks while the printer is operating, an alternative system of alignment is to misalign the printhead modules on the support beam 3 such that when the printhead assembly heats up to the operating temperature, the printheads move into alignment. This is easily achieved by adjusting the microscope by the set amount of misalignment required or simply misaligning the printhead modules by the required amount.

The required amount is calculated using the difference between the coefficients of thermal expansion of the printhead modules and the support beam, the length of each individual printhead module and the difference between ambient temperature and the MJ125-AU

I

operating temperature. The printer is designed to operate with acceptable module alignment within a temperature range that will encompass the vast majority of O environments in which it expected to work. A typical temperature range may be OOC to 00 040 0 C. During operation, the operating temperature of the printhead rise a fixed amount above the ambient temperature in which the printer is operating at the time. Say this increase is 50'C, the temperature range in which the alignment of the modules must be within the acceptable limits is 50C to 90 0 C. Therefore, when misaligning the modules cduring production of the printhead, the production temperature should be carefully maintained at 20 0 C to ensure that the alignment is within acceptable limits for the entire CNl 10 range of predetermined ambient temperatures 0°C to 40 0

C).

To minimize the difference in coefficient of thermal expansion between the printhead modules and the support beam 3, the support beam has a silicon core 5 mounted within a metal channel 6. The metal channel 6 provides a strong cost effective structure for mounting within a printer while the silicon core provides the mounting points for the printhead modules and also helps to reduce the coefficient of thermal expansion of the support beam 3 as a whole. To further isolate the silicon core from the high coefficient of thermal expansion in the metal channel 6 an elastomeric layer 7 is positioned between the core 5 and the channel 6. The elastomeric layer 7 allows limited movement between the metal channel 6 and the silicon core The invention has been described with reference to specific embodiments. The ordinary worker in this field will readily recognise that the invention may be embodied in many other forms.

MJ125-AU

Claims (7)

1. A printhead assembly for an inkjet printer, the assembly comprising: an elongate support member for mounting in an inkjet printer body; and, two or more printhead modules mounted in series along the support member, the support member having a structural component for strengthening the member, and a mounting component for mounting the printhead modules; wherein, 1 the mounting component is connected to the structural component in a manner that allows Srelative thermal expansion between the mounting component and the structural component, and Swherein the printhead modules are positioned on the support member such that they align when the support member is at its operating temperature but not necessarily at other temperatures
2. A printhead assembly according to claim 1 wherein each of the printhead modules has an array of inkjet nozzles formed on a monolithic substrate and the coefficient of thermal expansion of the monolithic substrates is similar to that of the mounting component.
3. A printhead assembly according to claim 2 wherein the mounting component is connected to the structural component via an elastomeric element that allows relative thermal expansion and contraction.
4. A printhead assembly according to claim 1 wherein the structural component is a beam with a channel section and the mounting component is a core house within the channel section.
A printhead assembly according to claim 4 wherein the channel is an aluminium extrusion and the core has ink supply channels for the printhead modules.
6. A printhead assembly according to claim 5 wherein the monolithic substrates and the core are predominantly formed from silicon.
7. A printhead assembly according to claim 1 wherein the printhead assembly is a pagewidth printer. MJ 125-AU
AU2004220745A 2000-03-09 2004-10-18 Modular printhead assembly with thermal expansion compensation Ceased AU2004220745B2 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
PCT/AU2001/000260 WO2001066357A1 (en) 2000-03-09 2001-03-09 Thermal expansion compensation for modular printhead assembly
AU4034301A AU4034301A (en) 2000-03-09 2001-03-09 Thermal expansion compensation for modular printhead assembly
AUPQ6111 2002-03-09

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
AU2001240343A Division AU2001240343B2 (en) 2000-03-09 2001-03-09 Thermal expansion compensation for modular printhead assembly

Publications (2)

Publication Number Publication Date
AU2004220745A1 AU2004220745A1 (en) 2004-11-04
AU2004220745B2 true AU2004220745B2 (en) 2006-02-02

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
AU2004220745A Ceased AU2004220745B2 (en) 2000-03-09 2004-10-18 Modular printhead assembly with thermal expansion compensation

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AU (1) AU2004220745B2 (en)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5528272A (en) * 1993-12-15 1996-06-18 Xerox Corporation Full width array read or write bars having low induced thermal stress
US5734394A (en) * 1995-01-20 1998-03-31 Hewlett-Packard Kinematically fixing flex circuit to PWA printbar
US5818478A (en) * 1996-08-02 1998-10-06 Lexmark International, Inc. Ink jet nozzle placement correction
JPH1110861A (en) * 1997-06-19 1999-01-19 Brother Ind Ltd Ink jet printer head
WO1999065691A1 (en) * 1998-06-19 1999-12-23 Lexmark International, Inc. An ink jet heater chip module including a nozzle plate coupling a heater chip to a carrier
US6325488B1 (en) * 1997-10-28 2001-12-04 Hewlett-Packard Company Inkjet printhead for wide area printing
JP2002280496A (en) * 2001-03-15 2002-09-27 Denki Kagaku Kogyo Kk Heat sink for electronic equipment

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5528272A (en) * 1993-12-15 1996-06-18 Xerox Corporation Full width array read or write bars having low induced thermal stress
US5734394A (en) * 1995-01-20 1998-03-31 Hewlett-Packard Kinematically fixing flex circuit to PWA printbar
US5818478A (en) * 1996-08-02 1998-10-06 Lexmark International, Inc. Ink jet nozzle placement correction
JPH1110861A (en) * 1997-06-19 1999-01-19 Brother Ind Ltd Ink jet printer head
US6325488B1 (en) * 1997-10-28 2001-12-04 Hewlett-Packard Company Inkjet printhead for wide area printing
WO1999065691A1 (en) * 1998-06-19 1999-12-23 Lexmark International, Inc. An ink jet heater chip module including a nozzle plate coupling a heater chip to a carrier
JP2002280496A (en) * 2001-03-15 2002-09-27 Denki Kagaku Kogyo Kk Heat sink for electronic equipment

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AU2004220745A1 (en) 2004-11-04

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Owner name: ZAMTEC LIMITED

Free format text: FORMER OWNER WAS: SILVERBROOK RESEARCH PTY LTD

MK14 Patent ceased section 143(a) (annual fees not paid) or expired