Patent Publication Number: US-8523323-B2

Title: Method and apparatus for mounting a fluid ejection module

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is the national stage of International Application Number PCT/US2009/042994, entitled “Method and Apparatus for Mounting a Fluid Ejection Module ”, filed on May 6, 2009,which is based on and claims the benefit of the filing date of U.S. Provisional Application No. 61/055,911, entitled “Method and Apparatus for Mounting a Fluid Ejection Module”, filed on May 23, 2008, both of which as filed are incorporated herein by reference in their entireties. 
    
    
     BACKGROUND 
     The following description relates to mounting a fluid ejection module to a print frame. An ink jet printer, typically includes an ink path from an ink supply to an ink nozzle assembly that includes nozzles from which ink drops are ejected. Ink drop ejection can be controlled by pressurizing ink in the ink path with an actuator, for example, a piezoelectric deflector, a thermal bubble jet generator, or an electrostatically deflected element. A typical printhead module has a line or an array of nozzles with a corresponding array of ink paths and associated actuators, and drop ejection from each nozzle can be independently controlled. In a so-called “drop-on-demand” printhead module, each actuator is fired to selectively eject a drop at a specific location on a medium. The printhead module and the medium can be moving relative one another during a printing operation. 
     In one example, a printhead module can include a semiconductor printhead body and a piezoelectric actuator. The printhead body can be made of silicon etched to define pumping chambers. Nozzles can be defined by a separate substrate that is attached to the printhead body. The piezoelectric actuator can have a layer of piezoelectric material that changes geometry, or flexes, in response to an applied voltage. Flexing of the piezoelectric layer pressurizes ink in a pumping chamber located along the ink path. 
     Printing accuracy can be influenced by a number of factors. Precisely positioning the nozzles relative to the medium can be necessary for precision printing. If multiple printheads are used to print contemporaneously, then precise alignment of the nozzles included in the printheads relative to one another also can be critical for precision printing. Maintaining alignment of the printheads during and after alignment and mounting can be important. 
     SUMMARY 
     This invention relates to mounting a fluid ejection module to a frame. In one aspect, the systems and methods disclosed herein feature a frame configured to mount a fluid ejection module that includes a mounting component having a mounting surface. One or more connectors are configured to detachably attach to the print frame and are positioned between the frame and the mounting surface of the fluid ejection module. A portion of a mating surface of the connector positioned adjacent to the mounting surface of the corresponding fluid ejection module is in direct contact with the mounting surface. One or more recesses are formed in at least one of either the mounting surface of the fluid ejection module or the mating surface of the connector, wherein the one or more recesses have a substantially uniform thickness and are filled with an adhesive. The adhesive is a substantially uniform layer formed within the one or more recesses and is cured after aligning the fluid ejection module to the frame. 
     In another aspect, the systems and methods disclosed herein feature attaching a first surface of a connector to the frame and positioning a mounting surface of the fluid ejection module adjacent to an opposing second surface of the connector. At least one of either the mounting surface or the opposing second surface of the connector includes one or more recesses filled with an adhesive. The fluid ejection module is aligned to the frame, and after aligning the fluid ejection module, the adhesive positioned between the mounting surface and the second surface of the connector is cured thereby securing the fluid ejection module to the connector. A portion of the mounting surface of the fluid ejection module and a portion of the second surface of the connector are in direct contact and the adhesive is positioned such that substantially all contraction of the adhesive during curing occurs perpendicular to the mounting surface. 
     In another aspect, the systems and methods disclosed herein feature a frame configured to mount one or more MEMS device assemblies. Each of the one or more MEMS device assemblies includes a mounting component having a mounting surface. One or more connectors are configured to detachably attach to the frame and are positioned between the frame and the mounting surfaces of the one or more MEMS device assemblies. A portion of a mating surface of the connector is positioned adjacent to the mounting surface of a corresponding MEMS device assembly and is in direct contact with the mounting surface. One or more recesses are formed in at least one of either the mounting surfaces of the one or more MEMS device assemblies or the mating surfaces of the one or more connectors. The one or more recesses have a substantially uniform thickness and are filled with an adhesive. The adhesive comprises a substantially uniform layer formed within the one or more recesses, wherein the adhesive corresponding to a MEMS device assembly is cured after aligning the MEMS device assembly to the frame. 
     In another aspect, the systems and methods disclosed herein feature a frame configured to mount one or more fluid ejection modules and one or more fluid ejection modules. Each fluid ejection module includes a mounting component having a first mounting surface and a second mounting surface. One or more connectors are configured to detachably attach to the frame. For each fluid ejection module, a first connector is positioned between the frame and the first mounting surface and a second connector is positioned between the frame and the second mounting surface. One or more recesses are formed in at least one or either the first and second mount surfaces of the one or more fluid ejection modules or a mating surface of the one or more connectors. The one or more recesses have a substantially uniform thickness and are filled with an adhesive. The adhesive includes a substantially uniform layer formed within the one or more recesses. For each fluid ejection module, the adhesive at an interface between the first mounting surface and the first connector is cured after aligning the fluid ejection module to the frame in a first direction, and the adhesive at an interface between the second mounting surface and the second connector is cured after aligning the fluid ejection module to the frame in a second direction and a third direction. 
     Implementations of the invention can include one or more of the following features. A screw can detachably attach the connector to the frame. At least a portion of the connector can comprise a light-transmissive material and the adhesive can be cured by exposure to light transmitted through the light-transmissive portion of the connector. The one or more fluid ejection modules can include fiducials for aligning the one or more fluid ejection modules to the frame. The adhesive can be positioned such that substantially all contraction of the adhesive during curing occurs perpendicular to the mounting surface. The mounting component can include one or more openings configured to receive a second adhesive at an interface between the mounting component and the connector. Each of one or more MEMS device assemblies can include an actuator, a sensor, or both. A system may also include a bracket having a first mating surface and a second mating surface, the first mating surface being attached by a first connector to the frame and the second mating surface being attached by a second connector to the mounting component. 
     One or more of the following additional features may also be included. Aligning the fluid ejection module to the frame can include aligning the fluid ejection module to one or more fluid ejection modules mounted to the frame. Curing the adhesive can include exposing the adhesive to ultra-violet light through the light-transmitting portion of the connector. Aligning the fluid ejection module can include aligning a mask to the frame, aligning a first pair of cameras to fiducials on the mask, and aligning the fluid ejection module with a second pair of cameras that are in a fixed relationship with the first pair of cameras. Aligning the fluid ejection module can include calibrating the first pair of cameras and the second pair of cameras using a calibrating mask. 
     Implementations of the invention can realize one or more of the following advantages. The connector can be detachable, so a fluid ejection module can be removed from the print frame after the adhesive is cured. Removal can be done without breaking an adhesive bond between the connector and the print frame, and potential damage to other fluid ejection modules and the print frame is mitigated or prevented. The adhesive may be positioned between the connector and the mounting component, and most contraction or shrinkage (if any) of the adhesive may occur in a direction perpendicular to the nozzle face. Because contraction in this direction will not have as significant an effect on fluid ejection module alignment as contraction in other directions, improved alignment may be obtained. The use of a transparent connector permits use of adhesives that are cured by ultraviolet light. Such adhesives can provide none, some, or all of the following advantages. Thermal expansion of parts can cause misalignment of the fluid ejection module, but ultraviolet light imparts little or no heat to the components being bonded, so little or no thermal expansion may occur during curing. Such adhesives may also have longer working times than other adhesives, which permits more time for proper alignment of the fluid ejection module. Such adhesives may also cure more rapidly than other types of adhesives, thus facilitating faster mounting of the fluid ejection module. In implementations using a secondary adhesive, the adhesive cured by ultraviolet light can maintain accurate alignment of the fluid ejection module while the secondary adhesive provides improved bond strength. 
     The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1A  is a perspective view of an example fluid ejection module mounted to a print frame. 
         FIG. 1B  is a perspective view of multiple fluid ejection modules mounted to a print frame. 
         FIG. 2  is a flowchart showing an example process for mounting the example fluid ejection module to the print frame. 
         FIG. 3A  is a perspective view of an example alignment apparatus. 
         FIG. 3B  is a perspective view of a portion of the alignment apparatus shown in  FIG. 3A . 
         FIG. 3C  is a schematic representation of an alignment mask. 
         FIG. 3D  is a schematic representation of a fiducial. 
         FIG. 3E  is a schematic representation of a calibration mask. 
         FIG. 3F  is a schematic representation of an alignment mask and a nozzle face. 
         FIG. 4A  is a cross-sectional perspective view of an example of a fluid ejection module mounted to a print frame. 
         FIG. 4B  is a cross-sectional perspective schematic representation taken along line B-B in  FIG. 4A . 
         FIG. 4C  is a cross-sectional planar schematic representation of a portion of the cross-section shown in  FIG. 4B . 
         FIG. 5  is a flowchart showing an example process for aligning and mounting a fluid ejection module using the apparatus shown in  FIG. 3A . 
         FIG. 6  is a cross-sectional schematic representation of an example fluid ejection module mounted to a print frame. 
     
    
    
     Like reference symbols in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
     A method, apparatus, and system are described for mounting a fluid ejection module to a frame (referred to herein as a “frame” or “print frame”). Precise alignment of a fluid ejection module is desirable for accurate fluid ejection, e.g., printing. When combining two or more fluid ejection modules for printing, each fluid ejection module should be precisely aligned relative to the other fluid ejection modules for printing accuracy. The method, apparatus, and system described herein advantageously provide for precise alignment of a fluid ejection module when mounting the fluid ejection module to a print frame, while also providing for easy removal of a single fluid ejection module, for example, to repair or replace the fluid ejection module. 
     A first surface of a connector is connected to a print frame. The connector can be formed at least in part from a material that allows the transmission of light, e.g., at least a portion of the connector can be transparent or translucent. In one example, the connector is formed from glass. The print frame is configured to mount one or more fluid ejection modules. A mounting surface of the fluid ejection module is positioned adjacent to an opposing second surface of the connector. The fluid ejection module is then aligned to the print frame and/or to one or more fluid ejection modules mounted to the print frame. After aligning the fluid ejection module, an adhesive  485  (see  FIG. 4B ) positioned between the mounting surface and the second surface of the connector can be cured, thereby securing the fluid ejection module to the connector. The fluid ejection module is thereby coupled to the print frame. Preferably, the connector is detachably connected to the print frame, and therefore, if the fluid ejection module must be removed, the connector can be detached from the print frame. 
       FIG. 1A  shows an example fluid ejection module  100  mounted to a print frame  140 . Some hidden features are illustrated with broken lines in  FIG. 1A . In some implementations, the fluid ejection module  100  can be included in a fluid ejection system including multiple fluid ejectors, e.g., printheads. Each fluid ejector can include a fluid ejection module, such as fluid ejection module  100 . The fluid ejection module  100  can include a rectangular plate-shaped printhead module, which can be a substrate fabricated using semiconductor processing techniques. Each fluid ejection module  100  can also include a housing to support the printhead module, along with other components such as a flex circuit to receive data from an external processor and to provide drive signals to the printhead module. The printhead module can include a substrate in which a plurality of fluid flow paths are formed. The printhead module also includes a plurality of actuators to cause fluid to be selectively ejected from the flow paths. Thus, each flow path with its associated actuator provides an individually controllable micro-electromechanical system (MEMS) fluid ejector. The substrate can include a flow-path body, a nozzle layer, and a membrane layer. The flow-path body, nozzle layer, and membrane layer can each be silicon, e.g., single crystal silicon. The fluid flow path can include a fluid inlet, an ascender, a pumping chamber adjacent the membrane layer, and a descender that terminates in a nozzle formed through the nozzle layer. Activation of the actuator causes the membrane to deflect into the pumping chamber, forcing fluid out of the nozzle. 
     Referring again to  FIG. 1A , the example fluid ejection module  100  shown includes a printhead casing  105 . The fluid ejection module  100  also includes a mounting component  110  having a mounting surface  120 . A connector  130  is positioned on the mounting surface  120 , between the fluid ejection module  100  and the print frame  140 . The connector  130  can be transparent or, alternatively, translucent. The connector  130  is attached to the print frame  140  using screws  135 , which are shown in broken lines in  FIG. 1A . Alternatively, a single screw  135  can be used, or other fastening techniques can be used, e.g., pins or rivets. As discussed above, preferably the connector  130  is detachably affixed to the print frame  140 , so as to allow relatively easy removal at a later time without causing damage to the print frame  140 . The connector  130  can have a mating surface  132  opposite the print frame  140 . The mounting component  110  of the fluid ejection module  100  is bonded to the connector  130  (e.g., to the mating surface  132  of the connector  130 ), for example, by the adhesive  485 . The mounting component  110  can include apertures (see  FIG. 4B ) configured to allow removal of the screws  135 , thereby allowing removal of the fluid ejection module  100  from the print frame  140 . 
     The fluid ejection module  100  includes a fluid inlet  170 , a fluid outlet  180 , and a substrate  190  configured for ejection of droplets of a fluid. The fluid can be, for example, a chemical compound, a biological substance, or ink. In other implementations, the fluid ejection module  100  does not include a fluid outlet  180  (which optionally can provide for a recirculation scheme for the printing fluid). 
       FIG. 1B  shows multiple fluid ejection modules  100  mounted to the print frame  140 . Each fluid ejection module  100  includes a mounting component  110 . Connectors  130  are positioned between each mounting component  110  and the print frame  140 , which as shown includes an optional upper portion  141 . Fluid inlets  170  supply fluid to each fluid ejection module  100 , and optional fluid outlets  180  provide a fluid return path for each fluid ejection module  100 . As is discussed in further detail below, the method, apparatus, and systems described herein allow for precise alignment of a fluid ejection module  100  not only to the print frame  140 , but relative to one or more other fluid ejection modules  100  as well. 
       FIG. 2  is a flowchart showing an example process  200  for mounting a fluid ejection module  100  to a print frame  140 . For illustrative purposes, the process  200  shall be described in the context of mounting the example fluid ejection module  100  shown in  FIG. 1A  to the example print frame  140 , however, it should be understood the process  200  can be implemented to mount a differently configured fluid ejection module  100  to the same or a differently configured print frame  140 . 
     The connector  130  is attached to the print frame  140  (step  210 ). As previously described, preferably the connector  130  is detachably attached to the print frame  140  to allow for relatively easy removal at a later time without damaging the print frame  140 . In one implementation, the connector  130  is attached to the print frame  140  by one or more screws received within threaded openings  145  (see  FIG. 38 ) formed within the print frame  140 . 
     Adhesive  485 , or some material that becomes adhesive on curing, is applied to a surface of the connector  130 , to the mounting surface  120  of the mounting component  110 , or both. The fluid ejection module  100  is positioned adjacent to the connector  130  with the mounting surface  120  facing the connector  130  (step  220 ). The fluid ejection module  100  is then aligned relative to the print frame  140  or relative to one or more neighboring fluid ejection modules  100  or both (step  230 ). The adhesive  485  can be formed from a material that, when uncured, allows for relative movement between the fluid ejection module  100  and the connector  130  to facilitate the alignment process. Once the alignment is achieved, the adhesive  485  can then be cured to affix the fluid ejection module  100  to the connector  130  (step  240 ). Once the adhesive  485  is cured, no significant relative movement of the fluid ejection module  100  and the connector  130  is possible. 
       FIG. 3A  shows an example alignment apparatus  300  supporting the print frame  140  and the fluid ejection module  100 . The alignment apparatus  300  is one example of a device that can be used to achieve the alignment step  230  described above. However, it should be understood that other configurations of the alignment apparatus  300  can be used, and the apparatus described is but one example. For illustrative purposes, the alignment apparatus  300  is described in the context of aligning the fluid ejection module  100  to the print frame  140 , although it should be understood that the alignment apparatus  300  can be used to align a differently configured fluid ejection module  100  to the same or a differently configured print frame  140 . 
     In this implementation, the alignment apparatus  300  includes a base  305 . A camera support rail  315  is mounted on the base  305 , and a camera support  325  is mounted on, and configured to move along, the camera support rail  315 . The camera support  325  supports a camera assembly  350 . A print frame support  330  is also mounted on the base  305 . The print frame support  330  supports the print frame  140  and a mask holder  335 . The mask holder  335  supports an alignment mask  340 . The alignment mask  340  can be used together with the camera assembly  350  to align one or more fluid ejection modules  100  to the print frame  140 , as discussed in more detail below. A manipulator assembly  355  is mounted to the base  305  by a manipulator base  345  and a manipulator rail  347 . The manipulator assembly  355  is configured to move the fluid ejection module  100  relative to the print frame. The manipulator base  345  is configured to move along the manipulator rail  347 . 
       FIG. 3B  is a close-up view of a portion of the alignment apparatus  300 . The fluid ejection module  100  is positioned in the print frame  140 . The connector  130  is positioned between the mounting component  110  and the print frame  140 , and the connector  130  is attached to the print frame  140 . The mask holder  335  supports the alignment mask  340 , and the alignment mask  340  includes fiducials  341 , which are discussed in more detail below. The manipulator assembly  355  includes a manipulator plate  380  configured such that movement of the manipulator plate  380  effects movement of the fluid ejection module  100  relative to the print frame  140 . 
     In this implementation, the camera assembly  350  includes two low magnification cameras  360  and four high magnification cameras  370 , although more or fewer cameras can be used. The high magnification cameras can be calibrated using a calibration mask  344  (see  FIG. 3E ), as discussed in more detail below. Light emitters  390  are configured to direct light at the connector  130 . In this implementation, the light emitters  390  are configured to emit ultraviolet light. 
       FIG. 3C  is a schematic representation of an implementation of the alignment mask  340 . The alignment mask  340  includes one row of fiducials  341 . The fiducials  341  can be used as reference marks for aligning the fluid ejection modules  100 . 
       FIG. 3D  is a schematic representation of an implementation of the fiducial  341 . In this implementation, the fiducial  341  includes conspicuity features  342  arranged around a fiducial point  343 . The conspicuity features  342  facilitate locating of the fiducial point  343  with the high magnification cameras  370 . References in this disclosure to alignment with a fiducial  341  can refer to alignment with a fiducial point  343 . That is, for example, aligning a high magnification camera  370  with a fiducial  341  can include aligning the high magnification camera  370  with a fiducial point  343 . The conspicuity features  342  can be sized to be conspicuous to a low magnification camera  360 , to a camera with no magnification, or to a human eye. 
       FIG. 3E  is a schematic representation of an implementation of the calibration mask  344 . The calibration mask includes fiducials  341  arranged in a first row  338  and a second row  339 . The fiducials  341  are configured such that the four high magnification cameras  370  are properly positioned when each of the four high magnification cameras  370  is aligned with a certain fiducial  341 . A high magnification camera  370  is aligned with a fiducial  371  when the center of the field of view of the high magnification camera  370 , or some other reference point within the field of view of the high magnification camera  370 , is aligned with a fiducial  371 . For example, the high magnification cameras  370  can be calibrated by alignment with the four fiducials  341  shown within a broken circle in  FIG. 3E . In this implementation, the spacing S between the fiducials  341  in the first row  338  is equal to the spacing S between the fiducials  341  in the second row  339 . The first row  338  and the second row  339  are parallel to each other and separated by a distance D. In some implementations, once calibrated, the four high magnification cameras  370  are maintained in a fixed relation with respect to each other after alignment, unless and until calibration is performed again. 
       FIG. 3F  is a schematic representation of an implementation of the alignment mask  340  and the substrate  190 . The substrate  190  has a nozzle face  195  that can include two or more fiducials  341  (two fiducials in this example). The fiducials  341  on the nozzle face  195  are positioned such that a line defined by such fiducials  341  is parallel to a line defined by the fiducials  341  on the alignment mask  340  when the nozzle face  195  is properly aligned. Because the substrate  190  is attached to the fluid ejection module  100 , proper alignment of the nozzle face  195  of the substrate  190  indicates proper alignment of the fluid ejection module  100 . 
     The fields of view of the four high magnification cameras  370  are shown as broken circles in  FIG. 3F . The fields of view each have a center represented by a crosshair in  FIG. 3F  for illustrative purposes. The centers of the fields of view of a first pair of high magnification cameras  370  define a first line  378 . The centers of the fields of view of a second pair of high magnification cameras  370  define a second line  379 . The high magnification cameras  370  are shown having been calibrated by the calibration mask  344 , as described above, so the first line  378  and the second line  379  are parallel to each other and separated by a distance D. The first pair  371  of high magnification cameras  370  can be aligned to two of the fiducials  341  on the alignment mask  340 . The second pair  372  of high magnification cameras  370  can be positioned over the nozzle face  195  of the fluid ejection module  100 . Because the first line  378  and the second line  379  are parallel, a line defined by the fiducials  341  on the nozzle face  195  is parallel to a line defined by the fiducials  341  on the alignment mask  340  if the nozzle face  195  is properly aligned. Aligning the nozzle face  195  to the second pair  372  of high magnification cameras  370  thus achieves the desired alignment. 
       FIG. 4A  shows a cross-section of the example fluid ejection module  100  mounted to the print frame  140 . The connector  130  is between the print frame  140  and the mounting surface  120  of the mounting component  110 . The connector  130  is affixed to the print frame  140  by a screw  135 , and the mounting component  110  is bonded to the connector  130 , for example the mating surface  132  of the connector  130  that is opposite the print frame  140 , by adhesive  485 . The fluid ejection module  100  is but one example of a fluid ejection module  100  that can be mounted to the print frame  140  by way of the connector  130 . Other configurations of fluid ejection modules can also be mounted to the print frame  140  using the connector  130 . For illustrative purposes, the example fluid ejection module  100  is described in further detail below. 
     An optional cover  476  can be attached to a surface of the mounting component  110  opposite the connector  130 . The cover  476  can include apertures  478  (see  FIG. 4B ) configured to allow access to the screw  135 , such as for removing the screw  135 . The cover  476  can be configured to prevent accumulation of fluid in any openings or recesses in the mounting component  110 . In some implementations, the cover  476  can be attached to the mounting component  110  after the mounting component is attached to the connector  130 . In an example where a secondary adhesive is applied, e.g., via openings  472  as discussed further below, the cover  476  is attached after applying the secondary adhesive. The cover  476  can be attached to the mounting component  110  by adhesion, a snap fitment, a fastener (e.g. screws, rivets, pins), or some other suitable mechanism. 
     Fluid can enter an upper supply chamber  410  of the fluid ejection module  100  from the fluid inlet  170  (see  FIG. 1A ). Fluid can pass from the upper supply chamber  410  through a supply filter  415  into a lower supply chamber  420 . From the lower supply chamber  420 , fluid can pass through an interposer  430  into the substrate  190 . The substrate  190  can include a fluid passage  192  or multiple passages  192  and one or more nozzles (not shown) formed on the nozzle face  195 . Fluid that is not ejected through any of the nozzles can exit the substrate  190  into a lower return chamber  450 . Fluid can pass from the lower return chamber  450  through a return filter  455  (optional) and into an upper return chamber  460 . Fluid can pass from the upper return chamber  460  into the fluid outlet  180  (see  FIG. 1A ). 
     In some implementations, a portion of the fluid passing through the fluid ejection module  100  does not enter the substrate  190 , but instead can bypass the substrate  190  and pass directly from the lower supply chamber  420  to the lower return chamber  450 . This bypass flow can facilitate a higher overall flow rate of fluid through the fluid ejection module  100 , which can, for example, remove contaminants from the fluid ejection module  100  and facilitate temperature control of the fluid ejection module  100 . 
       FIG. 4B  is a schematic representation of a cross-section of a portion of the assembly shown in  FIG. 4A  taken along line  4 B- 4 B shown in  FIGS. 1A and 4A . In this implementation, the mounting surface  120  includes contact areas  470  that contact the connector  130 , such as the mounting surface of the connector  130 . The mounting component  110  also includes one or more recesses  480  configured to receive adhesive  485 . Thus, the connector  130  and mounting surface  120  are in direct contact in the contact areas  470  and bonded with the adhesive  485  in the areas of the one or more recesses  480 . In other implementations, the connector  130  includes one or more recesses configured to receive the adhesive in addition to, or instead of, the one or more recesses  480  in the mounting surface  120  of the mounting component  110 . In implementations having multiple recesses  480 , all of the recesses  480  can be of a same depth. Providing a uniform depth for the recesses  480  can result in a uniform thickness of adhesive  485  across the entire connector  130  and among multiple connectors  130  used to attach a particular fluid ejection module  130 . This uniform thickness of adhesive  485  can reduce the likelihood of misalignment, such as by twisting of the fluid ejection module  100  during curing. 
     Non-uniform thickness of adhesive may be undesirable. For example, where the nozzle face  195  is intended to be orthogonal with the z direction, non-uniform thickness of the adhesive  485  may result in loss of this desired orthogonal relationship. If the adhesive  485  contracts during curing and the contraction causes movement of the fluid ejection module  100 , non-uniform thickness of the adhesive  485  can result in some portions of the fluid ejection module  100  moving more than others. In the absence of recesses  480 , the thickness of the adhesive  480  can be difficult to control for at least the reason that there is no direct contact between the mounting component  110  and the connector  130 . A uniform in thickness of adhesive  485  can prevent misalignment during curing if expansion or contraction of the adhesive  485  has equal effects at all portions of the fluid ejection module  100  that cancel each other out. The recesses  480  therefore facilitate proper alignment of the fluid ejection module by controlling the thickness of the adhesive  485 . 
     As discussed above, having the mounting surface  120  in direct contact with the connector at the contact areas  470  helps to maintain a desired relative position of the connector  130  and the mounting component  110  in the z direction, particularly if the adhesive  485  contracts during curing. The contact areas  470  can be referred to as “datums” or “datum features” since the contact areas  470  can establish a desired relationship between the fluid ejection module and the connector with higher accuracy and precision than might be attained without such features. Direct contact between the connector  130  and the contact areas  470  can mitigate or prevent relative movement of the connector  130  and the mounting component  110  in the z direction, e.g., if the mounting component  110  is resistant to compression or other deformation. Accordingly, the mounting component  110  can be composed of a material resistant to deformation. For example, the mounting component  110  can be composed of liquid crystal polymer (LCP). 
     The contact areas  470  can be formed in a manner during manufacturing of the mounting component  110  that provides a desired level of accuracy and precision in the contact between the mounting component  110  and the connector  130 . For example, the contact areas  470  can be manufactured with a desired degree of flatness across the mounting surface  120  of the mounting component  110  to minimize non-uniformity of contact between the mounting component  110  and the connector  130 . For example, the contact areas  470  can be manufactured with a degree of flatness across the mounting component  110  that facilitates contact of all contact areas  470  with the connector  130 . That is, it may be desirable that all contact areas  470  are in contact with the connector  430  so as to avoid warping of the connector  130 , the mounting component  130 , or both, before, during, or after curing of the adhesive  485 . The contact areas  470  can also be formed with a desired parallelism with the nozzle face  195  and with contact areas  470  on other mounting components  110  of a same fluid ejection module  100 . 
     Optionally, the mounting component  110  can include one or more openings  472  (see  FIGS. 4A and 4B ) for applying a secondary adhesive at the interface between the mounting component  110  and the connector  130 . The secondary adhesive can be of a non-ultraviolet curing type and may in some implementations provide additional bond strength between the mounting component  110  and the connector  130 . The secondary adhesive can be allowed to cure after the ultraviolet adhesive has been cured. The secondary adhesive can be, for example, an epoxy-type adhesive. The secondary adhesive can be introduced into a secondary recess  482  (see  FIG. 4B ) through the opening  472 . The optional cover  476  can cover the opening  472 . 
     In this implementation, the mounting component  110  includes apertures  490  that allow removal of the screws  135  or other such connection device. Removal of all of the screws  135  that attach the connector  130  to the print frame  140  allows detachment and removal of the connector  130  from the print frame  140  without damage to the print frame  140 . The fluid ejection module  100  can thereby be removed together with the connector  130  by removing the screws  135 . 
       FIG. 5  is a flowchart showing an alternative process  500  for mounting a fluid ejection module  100  to a print frame  140 . To align and mount a fluid ejection module  100 , the calibration mask  344  is placed in the mask holder  335  (step  505 ). The four high magnification cameras  370  are calibrated using the calibration mask  344  (step  515 ). The calibration mask  344  is then removed from the mask holder  335 , and the alignment mask  340  is placed in the mask holder  335  (step  525 ). The alignment mask  340  is aligned to the print frame  140  (step  535 ). The connector  130  is then attached to the print frame  140  (step  545 ). Adhesive is applied to the mounting component  110  so as to at least partially occupy the recess  480  (step  555 ). A fluid ejection module  100  is positioned in the print frame  140  such that a surface of the connector  130  contacts the contact areas  470  on the mounting surface  120  of the mounting component  110  (step  565 ). The first pair  371  of high magnification cameras  370  are then aligned with fiducials  341  on the alignment mask  340  (step  575 ). The manipulator assembly  355  engages with the fluid ejection module  100  by placing the manipulator plate  380  in contact therewith. The manipulator assembly  355  can then manipulate the fluid ejection module  100  so that the fiducials  341  on the nozzle face  195  align with the second pair  372  of high magnification cameras  370  (see  FIG. 3F ) (step  585 ). The light emitters  390  then shine light on the connector  130  (step  595 ). In this implementation, the light is ultraviolet light. Because the connector  130  in this implementation is transparent, the light travels through the connector  130  and reaches the adhesive. In this implementation, the adhesive is of a type that cures when exposed to ultraviolet light. The light emitters  390  shine light for a sufficient length of time to cure the adhesive. Additional fluid ejection modules  100  can be aligned and mounted to the print frame  140  in a similar manner. 
     Alternatively, adhesive can be applied to the connector  130 , and the adhesive can flow to at least partially occupy the recess  480  when the mounting surface  120  of the mounting component  120  is brought into contact with the contact areas  470 . Also, the first pair  371  of high magnification cameras  370  can be aligned with fiducials  341  on the alignment mask  340  before affixing the connector  130  to the print frame  140 , before applying adhesive to the mounting component  110 , before placing the fluid ejection module  100  in the print frame  140 , or at some other time. 
     In some implementations, the alignment apparatus  300  includes manipulator actuators configured to control the manipulator assembly  355 . The alignment apparatus  300  can further include a microprocessor programmed to receive input from the two pairs of high magnification cameras  370  and to provide signals controlling the manipulator actuators. The apparatus can further include actuators to control the movable camera support  325 . In one implementation, a microprocessor is programmed to receive input from the two pairs of high magnification cameras  370  and to control the camera support  325  actuators and the manipulator actuators. 
       FIG. 6  is a cross-sectional schematic representation of an alternative implementation of a system for mounting a fluid ejection module  100 . In this implementation, a first connector  532  and a second connector  536  are used such that the position of the fluid ejection module  100  relative to the print frame can be adjusted in three dimensions. In the particular example shown, a bracket  550  is included having a first mating surface  552  and a second mating surface  556 . The bracket  550  can be formed such that the first mating surface  552  and the second mating surface  556  are at right angles relative to each other. The first connector  532  is attached by a screw  135  to a surface of the print frame  140  proximate the printhead casing  105 . The first mating surface  552  of the bracket  550  is arranged proximate a surface of the first connector  532  that is opposite the print frame  140 . When so arranged, the second mating surface  556  is on a side of the bracket  550  opposite the print frame  140 . The bracket  550  is attached to the first connector  532  by an adhesive  485  that resides in a first recess  582  in the first mating surface  552  of the bracket  550 . The second connector  536  is attached by a screw  135  to the second mating surface  556  of the bracket  550 . The fluid ejection module  100  is arranged such that the mounting surface  120  of the mounting component  110  is proximate a surface of the second connector  536  that is opposite the second mating surface  556  of the bracket  550 . The mounting component  110  is attached to the second connector  536  by an adhesive  485  that resides in a second recess  586  formed in the mounting surface  120  of the mounting component  110 . The fluid ejection module  100  is thus attached to the print frame by way of the first connector  532 , the bracket  550 , and the second connector  536 . 
     By using the bracket  550 , the position of the fluid ejection module can be adjusted in the x, y and z directions relative to the print frame. For example, the bracket  550  can be positioned such that the second mating surface  556  is at a desired position in the z direction. Alternatively, the second connector  536  can already be attached to the bracket  550 , and the bracket  550  can be positioned such that the second connector  536  is at a desired position in the z direction. Further, to the extent not constrained by interference with the print frame  140  or other components, the bracket  550  can be rotated about the y direction to achieve a desired angular position. Adhesive  485  in the first recess  582  can then be cured to fix the position of the bracket  550 . 
     The fluid ejection module  100  can then be positioned on the second connector  536  and aligned as desired in the x direction and the y direction. The adhesive  486  in the second recess  586  can then be cured to attach the fluid ejection module to the second connector  536 . This implementation thus permits adjustment of the position of the fluid ejection module  100  in three dimensions. Where multiple fluid ejection modules  100  are being mounted in the print frame  140  and aligned, multiple brackets  550  can be used. For example, some or all of the brackets  550  can be positioned such that some or all of the second mating surfaces  556  or the second connectors  536  are in a common position in the z direction. This adjustability can allow for accurate alignment of the fluid ejection modules  100  in the z direction, for example, to compensate for manufacturing irregularities in the thickness of the mounting component  110  or the relationship between the mounting component  110  and other components of the fluid ejection module  100 , such as the substrate  190 . 
     Although the above example using two connectors to adjust the position of the fluid ejection module uses a bracket, other configurations are possible. Any number of connectors and other components (e.g., a bracket) can be used, so long as the fluid ejection module can be adjusted in three directions before becoming affixed to the one or more connectors being used to connect to the print frame. 
     In the implementations shown and described herein, the connector  130  is configured as a substantially rectangular component formed entirely from a material permitting the transmission of light. However, other configurations of the connector  130  are possible. For example, the connector  130  can be formed from two or more separate components rather than one integral component. The connector  130  can include portions that are not transparent or translucent, so long as there is at least one portion that allows the transmission of light so as to cure a light-sensitive (e.g., UV light sensitive) adhesive. In other implementations, the connector  130  can be opaque. Also, in some implementations, the adhesive can be of a type curable in a manner other than by light, such as by time, temperature, chemical reaction, or some other process, characteristic, or property. The connector  130  does not have to be configured in a substantially rectangular shape, and can be configured differently, for example, to conform to a differently configured mounting component of a fluid ejection module  100 . As described above, in one example, the connector  130  is formed from glass. However, in other implementations, the connector  130  can be formed from materials having a coefficient of thermal expansion similar to that of the fluid ejection module  100  and the print frame  140 . For example, the connector  130  can be composed of silicon, liquid crystal polymer (LCP), silicon carbide, quartz, or some other suitable material. The components described herein, for example, the mounting component  110 , the connector  130 , and the print frame  140 , can be formed from materials having a low coefficient of thermal expansion in some implementations. 
     The methods and apparatus described above are in the context of connecting a fluid ejection module to a print frame. However, the methods and apparatus can be used in other applications. For example, the connector and bonding techniques described can be used to with a MEMS device assembly in which MEMS devices, such as actuators or sensors, are formed in the substrate of the fluid ejection module  100 . This can permit precise alignment of multiple MEMS device assemblies relative to each other. 
     A fluid ejection module  100  and a mounting component  110  for the fluid ejection module are described above. An exemplary fluid deposited by the fluid ejection module  100  is ink. However, it should be understood that other fluids can be used, for example, electroluminescent material used in the manufacture of light emitting displays, liquid metals used in circuit board fabrication, or biological fluid. 
     The use of terminology such as “front,” “back,” “top,” and “bottom” throughout the specification and claims is for illustrative purposes only, to distinguish between various components of the fluid ejection module and other elements described herein. The use of “front,” “back,” “top,” and “bottom” does not imply a particular orientation of the fluid ejection module. Similarly, the use of horizontal and vertical to describe elements throughout the specification is in relation to the implementation described. In other implementations, the same or similar elements can be orientated other than horizontally or vertically as the case may be. 
     A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.