Patent Description:
Inkjet printers employing Memjet® pagewide technology are commercially available for a number of different printing applications, including desktop printers, digital inkjet presses and wideformat printers. Memjet® printers typically comprise one or more stationary inkjet printhead cartridges having a length of at least <NUM>, which are user-replaceable. For example, a desktop label printer comprises a single user-replaceable multi-colored printhead cartridge, a high-speed inkjet press comprises a plurality of user-replaceable monochrome printhead cartridges aligned along a media feed direction, and a wideformat printer comprises a plurality of user-replaceable printhead cartridges in a staggered overlapping arrangement so as to span across a wideformat pagewidth.

Analogue printing presses are conventionally used for relatively long print runs in which the cost of producing dedicated printing plates is economically feasible. Increasingly, industrial print systems use single-pass digital inkjet printing for relatively shorter print runs. Digital inkjet printing avoids the high set-up costs of producing printing plates and allows each print job to be tailored to a particular customer. Desirably, web feed systems for existing analogue print systems should be adaptable so as to enable 'drop-in' inkjet modules in place of, for example, offset printing stations. It is therefore desirable for inkjet modules to occupy minimal space with respect to a media feed direction, whilst allowing full color printing at high speeds with optimum print quality.

Inkjet printheads need to be replaced periodically and it would be desirable to enable printhead replacement with a high degree of reliability and accuracy so as to minimize alignment errors, especially in print systems having a plurality of printheads aligned along a media path. It would further be desirable to protect sensitive electronics, delivering power and data to the printhead, from ink mist during printing.

<CIT> describes a full-color pagewide printhead having two rows of chips receiving ink from a common manifold.

<CIT> describes a print module having a pivotable printhead carrier for printhead removal and replacement via sliding longitudinal insertion of the printhead through an access opening at one end of the printhead carrier.

<CIT>describes a print module which is liftable upwards from a sleeve for printhead removal and replacement.

<CIT> discloses a digital printing apparatus comprising a plurality of decorative elements, each provided with a respective casing.

According to the invention, there is provided an integrated inkjet module comprising:.

The printhead nest assembly, which is typically mounted to an underside of the printhead carrier, enables users to replace printheads in the inkjet module without requiring overhead access to the printhead carrier. The printhead nest assembly provides a convenient unit for replacing printheads, firstly, within the nest and thence within the inkjet module. The printhead is removable from the nest only when the printhead nest assembly is detached from the printhead carrier (i.e. wholly separated from the printhead carrier about all sides, such that the printhead nest assembly can be handled by a user as a discrete unit). Furthermore, the printhead nest assembly provides accurate and repeatable datuming of the printhead, as well as protection of sensitive electronic components from ink mist, as will be described in further.

Preferably, the inkjet module comprisesa lift mechanism operatively connected to the printhead carrier for lifting and lowering the printhead carrier relative to the chassis (i.e. away from and towards a media surface).

Preferably, the printhead carrier houses at least one of:.

Preferably, the nest is datumed to the printhead carrier via a first datuming arrangement.

Preferably, the first datuming arrangement comprises datum pins extending upwards from each end of the nest and datum blocks at a lower portion of the printhead carrier, each datum block having a respective datum surface for engagement with the nest and a respective opening configured for complementary engagement with the datum pins. The datum surface provides z-datuming while the datum pins provide x- and y-datuming.

Preferably, each datum block is relatively wider than the printhead along a media feed direction. A relatively wide datum block provides robust printhead datuming compared to fastening and datuming the printhead directly to the printhead carrier.

Preferably, the nest is fastened to the printhead carrier via screw fasteners having user-operable lever handles.

Preferably, the printhead is datumed to the nest via a second datuming arrangement.

Preferably, the second datuming arrangement comprises complementary datum surfaces at respective opposite ends of the printhead and the nest.

Preferably, the nest envelops all sides of the printhead.

Preferably, the nest is configurable in open and closed positions, the nest allowing removal of the printhead therefrom only in the open position and only when the printhead nest assembly is detached from the printhead carrier.

Preferably, in the closed position, the printhead is nestably secured within the nest.

Preferably, the nest comprises a pair of longitudinal side bars extending parallel with opposite longitudinal sides of the printhead and a pair of opposite end bars interconnecting the longitudinal side bars to define a nest cavity.

Preferably, a first longitudinal side bar is fixed and a second longitudinal side bar is relatively movable between the open and closed positions.

Preferably, the nest comprises a locking mechanism for locking the second longitudinal side bar in the closed position and releasing the second longitudinal side bar into the open position.

Preferably, the locking mechanism comprises a pair of nest levers cammingly engaged with the second longitudinal side bar to effect linear movement of the second longitudinal side bar towards and away from the first longitudinal side bar.

Preferably, each nest lever is pivotally mounted on a respective end bar and defines a cam slot engaged with a respective follower pin of the second longitudinal side bar.

Preferably, the printhead is engaged with the nest to form an ink mist seal, the ink mist seal protecting electronic circuitry housed in the printhead carrier from ink mist.

Preferably, the nest comprises opposed lips projecting inwardly towards the printhead from respective longitudinal side bars, each lip being engaged with a longitudinal edge of the printhead to at least partially define the ink mist seal.

Preferably, the printhead has opposite longitudinal flanges projecting laterally outwards therefrom, and wherein each longitudinal flange is positioned beneath and overlaps with a respective lip.

Preferably, the nest comprises datum pins projecting upwardly from each end bar at opposite ends of the nest cavity, each datum pin being configured for complementary engagement with the printhead carrier.

Preferably, each datum pin has a hollowed central bore for receiving a screw fastener of the printhead carrier.

Preferably, the inkjet module comprises:.

In a second aspect, there is provided a printhead nest assembly for facilitating printhead replacement, said printhead nest assembly comprising:.

wherein the nest is configurable in open and closed positions, the nest allowing removal of the printhead therefrom only in the open position and only when the printhead nest assembly is detached from the printhead carrier.

Preferred features of the printhead nest assembly are described above in connection with the first aspect.

In a third aspect, there is provided a method of replacing a printhead in an inkjet module, the method comprising the steps of:.

Preferably, the nest envelops all sides of the printhead in the printhead nest assembly.

Preferably, the step of opening the nest comprises releasing a locking mechanism of the nest.

Preferably, releasing the locking mechanism moves the second longitudinal side bar away from the first longitudinal side bar.

Preferably, the second longitudinal side bar is linearly movable towards and away from the first longitudinal side bar, and the locking mechanism comprises a pair of nest levers cammingly engaged with the second longitudinal side bar.

Preferably, the step of opening the nest comprises pivoting each nest lever about its respective pivot axis, each lever being pivotally mounted on a respective end bar and each pivot axis being parallel with a direction of droplet ejection from the printhead.

Preferably, the printhead is removed obliquely from the nest cavity via an upper side of the nest.

Preferably, the step of inserting the replacement printhead comprises the steps of:.

Preferably, the step of closing the nest comprises moving the second longitudinal side bar towards the first longitudinal side bar using the locking mechanism, thereby reforming the printhead nest assembly.

Preferably, the printhead is engaged with the nest in the printhead nest assembly to form an ink mist seal, the ink mist seal protecting electronic circuitry housed in the printhead carrier from ink mist.

Preferably, respective flanges extend laterally outwards from opposite longitudinal sides of the printhead, said flanges engaging with respective opposed lips projecting inwardly towards the printhead from opposite longitudinal side bars of the nest, thereby at least partially defining the ink mist seal.

In a fourth aspect, there is provided an integrated inkjet module comprising:.

wherein the printhead is movable between a print position in which the printhead projects through the longitudinal slot and a raised position in which the printhead is raised relative to the base plate.

Preferably, the base plate is C-shaped in plan view having a pair of transverse arms extending transversely from opposite ends of a longitudinal base member, the longitudinal slot being an open longitudinal slot defined between the transverse arms at a front side of the inkjet module.

Preferably, the inkjet module further comprises and rear- and end-walls extending upwards from the base plate.

Preferably, the lift mechanism comprises a lead screw mechanism having a pair of lead screws extending parallel with the posts, each lead screw having a respective lead nut connected to a respective bracket.

Preferably, each lead screw is operatively connected to a common lift motor via a pulley belt assembly.

Preferably, each sleeve bushing has a lower flange portion for datuming engagement with the base plate in the print position.

Preferably, the inkjet module comprises a capper for capping the printhead, the capper being linearly slidably movable towards and away from the printhead in a direction parallel with the transverse arms.

Preferably, the inkjet module comprises a cap cover positioned towards a rear side of the inkjet module, wherein the capper is covered by the cap cover during idle periods.

Preferably, the cap cover is pivotally mounted to the rear wall via rocker arms configured for camming engagement with respective cam guides positioned at each end of the capper, such that sliding movement of the capper towards the cap cover causes the cap cover to pivot and cover the capper.

Preferably, the inkjet module further comprises a wiper for longitudinally wiping the printhead in a direction parallel with a longitudinal axis thereof.

Preferably, the wiper is parked at one end of the longitudinal slot; and one of the brackets has a bracket roof and bracket sidewalls configured for covering the wiper in the print position.

Preferably, the cavity of the printhead carrier houses a supply module for the printhead.

Preferably, the supply module comprises one or more PCBs for supplying power and/or data to the printhead.

Preferably, the supply module further comprises a fan for cooling the PCBs and the brace has a truss structure allowing airflow from through an upper side of the printhead carrier.

Preferably, the printhead is mounted to the datum blocks via a nest enveloping the printhead.

Preferably, the datum blocks are datumed against the nest, the datum blocks having a width dimension greater than a width dimension of the printhead along a media feed direction.

As used herein, the term "inkjet module" is taken to mean an assembly of components, which includes an inkjet printhead, such as an elongate printhead configured for single-pass printing (known in the art as a "pagewide" or "linehead" printhead). The inkjet module typically also includes maintenance components and/or ink delivery components to provide a fully integrated inkjet system. The inkjet module may itself be a component of a modular print system, which may comprise, for example, a plurality of inkjet modules. Inkjet modules may be, for example, aligned along a media feed direction for very high-speed printing, or a plurality of inkjet modules may be positioned in a staggered overlapping arrangement across a media feed path for wide-format printing.

As used herein, the term "ink" is taken to mean any printing fluid, which may be printed from an inkjet printhead. The ink may or may not contain a colorant. Accordingly, the term "ink" may include conventional dye-based or pigment based inks, infrared inks, fixatives (e.g. pre-coats and finishers), 3D printing fluids, solar inks, and the like.

As used herein, the term "mounted" includes both direct mounting and indirect mounting via an intervening part.

Specific embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which:.

<FIG> show an integrated inkjet module <NUM> suitable for use in industrial printing systems. The inkjet module <NUM> is a self-contained unit comprising an elongate printhead <NUM> configured for single-pass printing, as well as requisite components for capping, wiping and delivering ink, power and data to the printhead in a compact, fully integrated assembly. The printhead <NUM> contains two rows of butting print chips <NUM> mounted on a singular uniform ink manifold, as described in <CIT> and <CIT>.

The inkjet module <NUM> may be used singly or as a modular component of a single-pass printing system comprising a plurality of such inkjet modules. For example, inkjet modules may be fully aligned in a stacked arrangement along a media feed path, or positioned in a staggered overlapping arrangement across a wider media feed path. Hence, the integrated inkjet module <NUM> allows facile construction of single-pass printing systems in a versatile and scalable manner. By way of example only, Applicant's co-filed US Application No._____ (Attorney Docket No. FXB029US) entitled "PRINTING UNIT WITH TANDEM INKJET MODULES" describes a high-speed industrial printing unit incorporating an opposing pair of such inkjet modules <NUM>.

The inkjet module <NUM> comprises a chassis <NUM> having an elongate base plate <NUM> with a rear wall <NUM> and a pair of opposite end walls <NUM> extending upwards from the base plate. Aside from providing the chassis <NUM> with structural rigidity, the rear wall <NUM> also serves as a support for mounting various fluidic components (e.g. pinch valves <NUM> and pumps <NUM>) and electronic components (e.g. module controller PCB <NUM>) on both its front and rear faces. Openings in the rear wall <NUM> allow fluidic connections from the rear face of the inkjet module <NUM>, without requiring overhead access.

The base plate <NUM> is generally C-shaped in plan view having a pair of transverse arms <NUM> extending from opposite ends of a longitudinal base member <NUM> along a nominal x-axis of the inkjet module <NUM>. An open longitudinal slot <NUM> is defined between the transverse arms <NUM> at a front side of the inkjet module <NUM>. The open longitudinal slot <NUM> extends parallel with a longitudinal axis along a nominal y-axis of the inkjet module <NUM> and is configured for receiving the elongate printhead <NUM>. Thus, the printhead <NUM> is asymmetrically positioned in the inkjet module <NUM> towards a front side thereof, allowing proximal positioning of printheads from oppositely oriented inkjet modules. The printhead <NUM> may be either lowered through the slot <NUM> for printing or raised above the base plate <NUM> for maintenance (e.g. capping and/or wiping).

A pair of posts <NUM> extend upwards from the transverse arms <NUM> of the base plate <NUM> at opposite ends of the open longitudinal slot <NUM>. Each post <NUM> is anchored to the base plate <NUM> at a lower end thereof and secured to a respective end wall <NUM> at an upper end thereof. A pair of brackets <NUM> are slidably engaged with the posts <NUM> via respective sleeve bushings <NUM> inserted in each bracket. Each sleeve bushing <NUM> is slidably movable relative to a respective post <NUM> allowing vertical linear movement of the brackets <NUM> towards and away from the base plate <NUM> along a nominal z-axis of the inkjet module <NUM>. A flanged portion <NUM> at a lower end of each sleeve bushing <NUM> is fastened to each bracket <NUM> and datums its respective bracket against the base plate <NUM> in the printhead lowered position (<FIG>).

An elongate printhead carrier <NUM> is fixedly supported between the brackets <NUM> and is linearly slidably movable with the brackets. The printhead carrier <NUM> comprises spaced apart front and rear carrier plates <NUM> interconnecting the brackets <NUM> and defining a cavity <NUM> therebetween for housing electronic components supplying power and data to the printhead <NUM>. A brace <NUM> interconnects upper parts of the carrier plates <NUM>, while a pair of datum blocks <NUM> interconnect lower parts of the carrier plates. The datum blocks <NUM> are positioned at opposite longitudinal ends of the printhead carrier <NUM> towards respective brackets <NUM>. The braced printhead carrier <NUM>, in combination with the sleeve bushings <NUM>, posts <NUM> and chassis <NUM> provide a robust support structure for the printhead <NUM>. The printhead <NUM> is itself secured within a complementary nest <NUM> to form a printhead nest assembly <NUM> (see <FIG>), which is mounted to the datum blocks <NUM> via screw fasteners <NUM> engaged with the nest.

The printhead <NUM> is linearly slidably movable towards and away from the base plate <NUM> between a printing position (<FIG>) and a maintenance position (<FIG>) by means of a lift mechanism operatively connected to each bracket <NUM>. As best shown in <FIG>, the lift mechanism comprises a pair of lead screws <NUM> rotatably mounted to the base plate <NUM> and extending upwards parallel with the posts <NUM>. Each lead screw <NUM> has respective lead nut <NUM> fixedly connected to a respective bracket via a lead nut connector <NUM>. The lead screws <NUM> are rotatable by means of an interconnecting pulley belt assembly operatively <NUM> connected to a common lift motor <NUM>. Accordingly, the printhead <NUM> may be moved between raised and lowered positions by actuation of the lift motor <NUM>, which rotates the leads screws <NUM> simultaneously via the pulley belt assembly <NUM>, thereby lifting or lowering the printhead carrier <NUM> connected to the lead nuts <NUM> via the brackets <NUM>.

As best shown in <FIG>, the inkjet module <NUM> comprises a wiper carriage <NUM>, having a microfiber wiping web <NUM>, parked at one end of the longitudinal slot <NUM>. In the printhead raised position, the wiper carriage <NUM> is movable longitudinally along the length of printhead <NUM> by means of a wiper movement mechanism <NUM> mounted on a longitudinal wiper support <NUM> in order to wipe ink and debris from the printhead face. In the printhead lowered position (<FIG>), one of the brackets <NUM>, having a bracket roof <NUM> and bracket sidewalls <NUM>, shields the wiper carriage <NUM>. Thus, the bracket roof <NUM> and bracket sidewalls <NUM> provide at least some protection from ink mist and/or debris that may contaminate the wiper carriage <NUM> via an open front face of the inkjet module <NUM> during printing.

The inkjet module <NUM> further comprises a capping assembly <NUM> which is parked towards the rear wall <NUM> and linearly slidably movable towards and away from the printhead <NUM> along transverse capper rails <NUM> by means of rack-and-pinion mechanism <NUM>. The capping assembly comprises <NUM> a capper base <NUM> slidably engaged with the capper rails <NUM>, a perimeter printhead capper <NUM> mounted on the capper base, and cam guides <NUM> mounted fast with the capper base at opposite ends of the printhead capper. In its parked (covered) position shown in <FIG>, the printhead capper <NUM> is covered with a cap cover <NUM> pivotally mounted to the rear wall <NUM> of the chassis <NUM>. The cap cover <NUM> takes the form of a rigid plate, which seals against a perimeter seal <NUM> of the printhead capper <NUM> and maintains a humid environment within the printhead capper whenever the printhead capper is not being used for capping the printhead <NUM>. The wiper movement mechanism <NUM> is mounted on the wiper support <NUM>, which is fixedly attached to the rear wall <NUM> directly above the cap cover <NUM>.

For printhead capping, the capping assembly <NUM> is laterally moved away from the cap cover <NUM> into alignment with the printhead <NUM>, and the printhead is gently lowered onto the printhead capper <NUM> into a capped position using the lift mechanism. With the printhead raised, transverse movement of the capping assembly <NUM> back towards the rear wall <NUM> engages a rear cam surface <NUM> of the cam guides <NUM> with an engagement node <NUM> of respective rocker arms <NUM> at each end of the cap cover. The rocker arms <NUM> are pivotally mounted to the rear wall <NUM> and allow the cap cover <NUM> to pivot upwards on engagement with the cam guides <NUM>, thereby enabling the capping assembly <NUM> to slidingly traverse under the cap cover. Once the capping assembly <NUM> has reached its rearmost parked position, the cap cover <NUM> pivots back downwards, by virtue of the profile of the cam guides <NUM> and rocker arms <NUM>, into the covered position in which the printhead capper <NUM> is covered by the cap cover.

<FIG> shows the rear cam surface <NUM> of the cam guide <NUM> engaged with an engagement node <NUM> of the rocker arm <NUM> as the capping assembly <NUM> approaches the rear wall <NUM>. <FIG> shows the rocker arm <NUM> pivoted upwards as the capping assembly transitions towards its covered position. <FIG> shows the capping assembly <NUM> in its rearmost parked position with the rocker arm <NUM> pivoted back into a horizontal plane and the printhead capper <NUM> covered by the cap cover <NUM>. For printhead capping, the capping assembly <NUM> slides from its parked position shown in <FIG> towards the printhead <NUM>. A front cam surface <NUM> of the cam guide <NUM> engages with the engagement node <NUM> of the rocker arm <NUM> in order to pivot the rocker arm upwards and allow sliding movement of the capping assembly towards the printhead <NUM>.

As foreshadowed above, and referring now to <FIG>, the printhead carrier <NUM> defines a cavity <NUM> between front and rear plates <NUM> thereof. The cavity <NUM> houses a supply module <NUM>, which includes front and rear PCBs <NUM> for supplying power and/or data to the printhead <NUM>. A cooling fan <NUM> is positioned between the PCBs <NUM> for cooling electronic components with cool air drawn into the cavity <NUM> from an upper side of the printhead carrier <NUM>. The brace <NUM>, which defines a roof portion of the printhead carrier <NUM>, has an open truss structure, which allows circulation of cool air through the cavity <NUM> and between the PCBs <NUM>. The supply module <NUM> further comprises ink couplings <NUM> for engagement with complementary ink ports <NUM> at opposite ends of the printhead <NUM>. The supply module <NUM> forms ink and electrical connections with the printhead <NUM> upon installation of the printhead (secured in its printhead nest assembly <NUM>) onto the printhead carrier <NUM>, as will be explained in more detail below.

<FIG> show the printhead nest assembly <NUM> in isolation. As shown in <FIG>, the nest is in its closed position with the printhead <NUM> nestably secured within the nest <NUM> and enveloped about all sides by the nest. In <FIG>, the nest <NUM> is in its open position, which allows removal of the printhead <NUM> from the nest, but only when the printhead nest assembly <NUM> is fully detached from the printhead carrier <NUM>. In other words, the printhead <NUM> must be united with the nest <NUM> to form the printhead nest assembly <NUM> before the printhead (e.g. a replacement printhead) can be installed in the inkjet module 1by fastening the nest <NUM> to the printhead carrier <NUM>.

The nest <NUM> is configured for detachable fastening to the printhead carrier <NUM> via the pair of screw fasteners <NUM>, which extend vertically through a height of the printhead carrier <NUM>. Each screw fastener <NUM> has a screw lever <NUM> at one end which is user-accessible from above printhead carrier <NUM> and a screw tip projecting through a recessed opening <NUM> in a respective datum block <NUM> (<FIG>). An upper surface of the nest <NUM> has a pair of datum pins <NUM> configured for complementary engagement with the recessed openings <NUM> of the datum blocks <NUM>. For installation of the printhead nest assembly <NUM>, each screw fastener <NUM> is screwed through a hollowed bore <NUM> of a respective datum pin <NUM> and into a threaded nut insert <NUM> of the nest <NUM>. Thus, the printhead nest assembly <NUM> may be firmly secured to the printhead carrier <NUM> with accurate datuming controlled by complementary datuming engagement between the datums pins <NUM> and the recessed openings <NUM> in each datum block <NUM>. The nest <NUM> enables the use of relatively large datum pins <NUM>, separate from the printhead <NUM>, for highly accurate and repeatable datuming between the printhead carrier <NUM> and the printhead nest assembly <NUM>.

Screw fastening of the printhead nest assembly <NUM> to the printhead carrier <NUM> via the datum blocks <NUM> simultaneously forms ink and electrical connections between the printhead <NUM> and the supply module <NUM>. Ink ports <NUM> at opposite ends of the printhead <NUM> are raised into engagement with ink connectors <NUM> of the supply module <NUM>. Likewise, electrical contacts <NUM> extending along opposite longitudinal sides of the printhead <NUM> are brought into electrical contact with complementary PCB contacts <NUM> of respective PCBs <NUM> in the supply module <NUM>. Spring-biased PCB mounting plates <NUM> of the supply module <NUM> allow the PCBs <NUM> to flex laterally away from each other while the printhead <NUM> is raised between the PCBs during installation of the printhead nest assembly <NUM>. The spring bias provides reliable electrical connections, while the requisite insertion force (for both the ink and electrical connections) is provided by the screw fasteners <NUM>, which are readily operable by the user using the screw levers <NUM>. Accordingly, this arrangement obviates the movable supply assembly and two-staged ink and electrical connections, described in <CIT>.

The printhead nest assembly <NUM> may be fastened to the printhead carrier <NUM> either in the printhead lowered (<FIG>) or printhead raised position (<FIG>), depending on whichever configuration is more accessible in a particular modular set-up of the inkjet module <NUM>. As shown in <FIG>, the printhead nest assembly <NUM> has been removed in the printhead lowered position.

<FIG> disclose an embodiment which is not covered by the scope of the claims. Referring now to <FIG> and <FIG>, the nest <NUM> is configurable in a nest open position for printhead removal and insertion. The nest <NUM> comprises first and second longitudinal side bars <NUM> and <NUM> extending parallel with opposite longitudinal sides of the printhead <NUM> and a pair of shorter transverse end bars <NUM> interconnecting each end of the longitudinal side bars to define a rectangular (oblong) nest cavity <NUM>. The first longitudinal side bar <NUM> and end bars are fixed <NUM>, while the second longitudinal side bar <NUM> is movable towards and away from the first longitudinal side bar between the open and closed positions.

Each end bar <NUM> has a dowel pin <NUM> received the movable second longitudinal side bar <NUM>. Sliding movement of the second longitudinal side bar <NUM> relative to the fixed dowel pins <NUM> provides relative linear movement of the second longitudinal side bar towards and away from the first longitudinal side bar <NUM>.

Movement of the second longitudinal side bar is <NUM> effected by means of a locking mechanism, which configures the nest <NUM> in either the closed or open positions. The locking mechanism comprises a pair of nest levers <NUM>, each nest lever being pivotally attached to a respective end bar <NUM> and having a pivot axis perpendicular to a horizontal plane of the nest (i.e. parallel to a direction of droplet ejection from the printhead <NUM>). Each nest lever <NUM> defines a cam slot <NUM> engaged with a respective follower pin <NUM> extending parallel with the pivot axis at opposite ends of the second longitudinal side bar <NUM>. Pivoting motion of each nest lever <NUM> away from its respective end bar <NUM> moves the second longitudinal side bar <NUM> linearly away from the first longitudinal side bar <NUM>, by virtue of the cam engagement between the cam slots <NUM> and follower pins <NUM>, in order to open the nest <NUM>. Conversely, pivoting motion of each nest lever <NUM> towards respective end bars <NUM> moves the second longitudinal side bar <NUM> linearly towards the first longitudinal side bar <NUM> in order to lock the nest <NUM> closed. Each nest lever <NUM> has a finger-grip portion <NUM> at an opposite end from the pivot axis for user actuation of the locking mechanism.

In its closed position, the nest <NUM> is configured to form an ink mist seal around the printhead <NUM>. The ink mist seal inhibits the ingress of ink mist into the supply module <NUM> and thereby protects sensitive electronic circuitry on the PCBs <NUM> from fouling by any ink mist generated during printing. The ink mist seal comprises a pair of opposed first and second longitudinal lips <NUM> projecting inwardly towards the printhead from respective first and second longitudinal side bars <NUM> and <NUM>. Each lip <NUM> is engaged with a longitudinal edge region <NUM> of the printhead <NUM> so as to form part of the ink mist seal.

In order to insert the printhead <NUM> into the nest <NUM>, the nest is firstly configured into its open position as shown in <FIG>. The printhead is then laterally guided into the open nest cavity <NUM> at an oblique angle (<FIG>) towards the first longitudinal side bar <NUM>. A first longitudinal flange <NUM> at one side of the printhead <NUM> is initially held at an angle below the longitudinal lip <NUM> of the first longitudinal side bar <NUM> so as to overlap with the lip, and then the printhead is rotated about its longitudinal axis into a plane parallel with a plane of the nest. Printhead datums <NUM> at opposite ends of printhead <NUM> engage with complementary nest datums <NUM> to provide accurate and repeatable positioning of the printhead within the nest (<FIG>).

With the printhead <NUM> properly positioned inside the open nest (<FIG>), the nest levers <NUM> are pivoted inwards so as to close the second longitudinal side bar <NUM> and lock the nest <NUM> into its closed position, thereby forming the locked printhead nest assembly <NUM> (<FIG>). Closure of the nest <NUM> moves the longitudinal lip <NUM> of the second longitudinal side bar <NUM> towards the printhead <NUM> to complete the ink mist seal with each longitudinal flange <NUM> of the printhead positioned beneath and overlapping with its respective longitudinal lip.

The complete printhead nest assembly <NUM> may then be secured to the printhead carrier <NUM> using the screw fasteners <NUM> as described above. For printhead removal, the reverse procedure is followed whereby the printhead nest assembly <NUM> is detached from the printhead carrier <NUM>, the nest opened using the nest levers <NUM>, and the printhead <NUM> removed obliquely from the open nest <NUM>.

Claim 1:
An integrated inkjet module comprising:
a chassis (<NUM>);
a printhead carrier (<NUM>) mounted to the chassis; and
a printhead nest assembly (<NUM>) having (i) a nest fastened to an underside of the printhead carrier and (ii) a user-replaceable printhead nestably secured within the nest,
characterized in that
the printhead nest assembly is detachable from the printhead carrier as a discrete unit, and the printhead is removable from the nest only when the printhead nest assembly is detached from the printhead carrier.