Orientation-independent print modules and arrays of multiple print modules

Abstract

The inkjet print module includes a printhead including first and second rows of print tips, the printhead having 180 degree rotational symmetry about a print axis parallel to a drop ejection direction, a cradle for removably receiving the printhead, and control circuitry for distributing data signals to the printhead via first and second data paths of the inkjet print module. The cradle is configurable to receive the printhead in first and second printhead orientations relative to the print module, the second printhead orientation being rotated 180 degrees about the print axis relative to the first printhead orientation. The control circuitry is configurable to reverse the distribution of data signals between the first and second data paths.

Description

[Technical Field]

[0001] The present invention relates to a printing module adapted for a plurality of module arrays. It was primarily developed to enable high-quality single-pass printing using a plurality of inkjet printing modules while enabling exchange of printheads between modules. [Background Art]

[0002] Inkjet printers employing Memjet® technology are commercially available in various printing configurations, such as desktop printers, digital inkjet presses, and wide-format printers. Memjet® printers typically include one or more stationary inkjet printheads, which are user-replaceable. For example, a desktop label printer includes a single user-replaceable full-color printhead, while a wide-format printer comprises a plurality of user-replaceable printheads arranged in a staggered overlapping arrangement across a wide-format media path.

[0003] U.S. Pat. No. 10,076,917, the content of which is incorporated herein by reference, describes a commercial page-wide printing system including an N×M two-dimensional array of monochrome printing modules and corresponding maintenance modules. Providing OEM customers with the flexibility to select the size and number of printheads in an N×M module array enables access to a broader commercial digital printing market that was traditionally served by offset printing systems. Nevertheless, integrating printing modules and maintenance modules into an inkjet printing press still requires development work by the OEM.

[0004] U.S. Patent No. 11,014,366 (the contents of which are incorporated herein by reference) describes a printing module having a full-color printhead with double redundancy for each color to provide superior print quality. This printing module has a fully integrated capper and wiping system for printhead maintenance and can be easily installed as a low-cost full-color print engine for many printing applications (e.g., direct mail, flexible packaging, corrugated cardboard, etc.).

[0005] To expand the market for integrated inkjet printing modules, such as those described in U.S. Patent No. 11,014,366, it is desirable to arrange such modules in an overlapping configuration along the media path to broaden the printable area. Precise alignment of the printheads is necessary to stitch the overlapping printheads, and it is desirable to position the printheads as close together as possible to minimize the effects of misalignment. The requirement to position overlapping printheads as close together as possible typically requires different mechanical designs for “forward-facing” and “backward-facing” printing modules, as described in U.S. Patent No. 9,061,531 (the contents of which are incorporated herein by reference). Nevertheless, it would be desirable to provide printing modules that can be positioned in either a backward-facing or forward-facing configuration with minimal adaptation of the printing module.

[0006] Furthermore, in a page-wide array, it is desirable to allow users to swap printheads between print modules regardless of the position or orientation of the print modules. [Overview of the project]

[0007] In the first embodiment, an inkjet printing module is provided, and this inkjet printing module is A printhead comprising first and second rows of print chips, having 180 degrees of rotational symmetry about a printing axis parallel to the droplet ejection direction, A cradle for removably receiving the print head, The inkjet printing module includes a control circuit for distributing data signals to the print head via first and second data paths, The cradle can be configured to accept print heads in first and second print head directions relative to the printing module, wherein the second print head direction is rotated 180 degrees around the printing axis relative to the first print head direction. The control circuit can be configured to invert the distribution of data signals between the first data path and the second data path.

[0008] The print modules according to the first embodiment are advantageous in that they can be arranged alternately ("forward" and "backward") across the media path, and that print heads can be swapped between print modules as needed. The print modules are virtually independent of their orientation, insofar as the adaptations required for a "backward" print module to use the same print head as a "forward" print module are minimized. In effect, all that is needed to reverse a print module in the array is to reverse the control circuit (e.g., via a user-activated switch) and change the order of ink connections to the print modules. Thus, the same print module can be used in either orientation, and the print head can be swapped between forward-facing and backward-facing modules without the risk of ink color mixing, as will be described in more detail below.

[0009] Preferably, the first and second rows of the printed chips have 180-degree rotational symmetry around the printing axis.

[0010] Preferably, the cradle includes a configurable key slot assembly for complementary engagement with a fixed printhead key feature, wherein the key slot assembly configures the cradle to accept the printhead in either a first printhead direction only or a second printhead direction only.

[0011] Preferably, the fixed printhead key feature is rotationally asymmetrical about the printing axis, regardless of the rotational symmetry of the printhead.

[0012] Preferably, the printhead has multiple printhead ink ports at both ends, and the inkjet printing module has complementary ink couplings for detachable connection to the printhead ink ports.

[0013] Preferably, the inkjet printing module further comprises multiple module ink ports for connecting to multiple corresponding ink reservoirs that supply ink to the ink coupling, and each module ink port is connectable to any one of the multiple ink reservoirs such that the order of ink supplied to the printhead ink ports can be reversed.

[0014] Preferably, the inkjet printing module further includes a switch (e.g., a toggle switch) operably connected to a control circuit to invert the distribution of data signals.

[0015] Preferably, the control circuit includes a controller chip configured to receive print data and distribute the data signal between a first data path and a second data path.

[0016] Preferably, the first and second data paths include first and second module contacts, respectively, and each of the first and second module contacts is configured to be electrically connected to either the first or second printhead contact in either the first or second printhead direction.

[0017] Preferably, the print head is positioned asymmetrically toward one side of the inkjet printing module.

[0018] Preferably, the inkjet printing module is Printed head cappers, Printhead wiping system, A lift mechanism for raising and lowering the print head relative to the media path. It further comprises one or more of the following.

[0019] In a second embodiment, a printing system is provided that includes a plurality of inkjet printing modules as described above, wherein the plurality of inkjet printing modules A first inkjet printing module disposed on a media path in a first module direction with respect to the media path, the first inkjet printing module comprising print heads received in their respective cradles in a first print head direction with respect to the first printing module such that a first row of print chips of the first printing module is upstream of a second row of print chips, A second inkjet printing module is positioned on a media path in a second module direction rotated 180 degrees with respect to a first module direction, and comprises a second printing module having print heads received in their respective cradles in a second print head direction relative to the second printing module such that the first row of print chips of the second printing module is downstream of the second row of print chips, The data signals corresponding to the first color plane are distributed only through the first data path of the first printing module. The data signals corresponding to the first color plane are distributed only through the second data path of the first printing module.

[0020] In one embodiment, the first and second printing modules are arranged across the media feed path in a staggered overlapping arrangement such that the first and second print heads overlap each other. However, if required, the printing modules can be arranged in alternative arrangements.

[0021] Preferably, ink is supplied to each print head such that the ink order in the first and second rows of print chips relative to the media path is the same in both the first and second inkjet printing modules.

[0022] Preferably, each row of print chips is configurable to print two colors of ink.

[0023] Preferably, a print head contaminated with ink and removed from the first or the second inkjet printing module is replaceable in either the first or the second inkjet printing module.

[0024] Preferably, a first switch operably connected to the control circuit of the first inkjet printing module is deactivated, and a second switch operably connected to the control circuit of the second inkjet printing module is activated, whereby the second switch is configured to invert a data signal distributed to the first inkjet printing module via the first and second data paths of the second inkjet printing module.

[0025] In a third aspect, there is provided an inkjet printing module, wherein the inkjet printing module: a print head including first and second rows of print chips, the print head having 180-degree rotational symmetry about a printing axis parallel to a droplet ejection direction; a fixed print head key feature extending from the print head, the fixed print head key feature being rotationally asymmetric about the printing axis regardless of the rotational symmetry of the print head; A cradle for detachably receiving a print head, comprising a configurable key assembly for complementary engagement with a fixed print head key feature, the key assembly being selectively configurable to either one of a first cradle configuration and a second cradle configuration. In the first cradle configuration, the cradle receives the print head only in a first print head orientation, In the second cradle configuration, the cradle receives the print head only in a second print head orientation, the second print head orientation being rotated 180 degrees about a print axis relative to the first print head orientation.

[0026] Preferably, the key assembly comprises a pair of slots defined in a portion of the cradle, and a shutter for selectively blocking either one of the slots.

[0027] Preferably, the shutter is slidable between the pair of slots.

[0028] Preferably, the cradle comprises a print head carrier for slidably receiving the print head in a longitudinal direction, the print head carrier including the key assembly.

[0029] Preferably, the key assembly is disposed at a first end of the print head carrier, and the print head carrier receives the print head at the first end.

[0030] Preferably, the print head carrier is pivotable about a second end opposite the first end thereof.

[0031] Preferably, the print head comprises a plurality of print head ink ports at opposite ends thereof, and an inkjet printing module comprises complementary ink couplings for detachably connecting to the print head ink ports.

[0032] Preferably, the inkjet printing module further comprises multiple module ink ports for connecting to multiple corresponding ink reservoirs that supply ink to the ink coupling, and each module ink port is connectable to any one of the multiple ink reservoirs such that the order of ink supplied to the printhead ink ports can be reversed.

[0033] In a fourth aspect, a printing system is provided that includes a plurality of inkjet printing modules as described above, wherein the plurality of inkjet printing modules A first inkjet printing module disposed on a media path in a first module direction with respect to the media path, the first inkjet printing module comprising print heads received in their respective cradles in a first print head direction with respect to the first printing module such that a first row of print chips of the first printing module is upstream of a second row of print chips, A second inkjet printing module is positioned on a media path in a second module direction rotated 180 degrees with respect to a first module direction, and comprises a second printing module having print heads received in their respective cradles in a second print head direction relative to the second printing module such that the first row of print chips of the second printing module is downstream of the second row of print chips, The key assembly of the first inkjet printing module is configured to engage complementarily with the fixed printhead key feature portion of each printhead only in the first printhead direction. The key assembly of the second inkjet printing module is configured to engage complementarily with the fixed printhead key feature of each printhead only in the second printhead direction.

[0034] Preferably, the first and second inkjet printing modules are arranged to cross the media feed path in a staggered overlapping arrangement such that the first and second print heads overlap.

[0035] Preferably, ink is supplied to each printhead such that the ink sequence in the first and second rows of print chips relative to the media path is the same in both the first and second inkjet printing modules.

[0036] Preferably, each row of the print chip can be configured to print two colors of ink.

[0037] In a fifth aspect, a method is provided for configuring an orientation-independent inkjet printing module for use in either a first or second module direction with respect to a media path, wherein the second module direction is rotated 180 degrees with respect to the first module direction, and the method is A step of configuring a key assembly to correspond to either a first or a second module orientation, wherein the key assembly determines the orientation of each print head relative to the inkjet printing module. The steps include configuring a switch to correspond to either a first or a second module direction, wherein the switch is operably connected to a controller circuit that distributes data signals to a print head via first and second data paths, and the switch inverts the distribution of data signals between the first and second data paths.

[0038] Preferably, the key assembly has a pair of slots defined in a portion of the cradle and a shutter for selectively covering one of the slots.

[0039] Preferably, configuring the key assembly includes the step of sliding a shutter so as to selectively cover one of the slots.

[0040] Preferably, the method includes the step of arranging first and second inkjet printing modules across a medium feed path, wherein the first inkjet printing module is arranged and configured in the first module direction, and the second inkjet printing module is arranged and configured in the second module direction.

[0041] Preferably, the printheads are arranged asymmetrically toward one side of the inkjet printing module, with the printheads of the first and second inkjet printing modules positioned close to the media path.

[0042] Preferably, the method further includes the step of connecting each ink reservoir to the module ink ports of the first and second inkjet printing modules, with the order of ink connections being reversed for the second inkjet printing module compared to the first inkjet printing module.

[0043] In this specification, “180-degree rotational symmetry printhead” means that the printhead has 180-degree rotational symmetry as a whole with respect to its functional and mechanical features, such as the print chip, ink ports, datums, printhead contacts, ink manifold, printhead housing, and datums. However, it will be understood that the 180-degree rotational symmetry of the printhead does not include one or more asymmetric key features specifically provided to control the direction in which the printhead is inserted into the cradle. Naturally, the 180-degree rotational symmetry does not necessarily include non-functional features such as labels, surface patterns, or decorations. Furthermore, to avoid any doubt, the 180-degree rotational symmetry of the printhead refers only to the mechanical features of the printhead and does not include, for example, the ink contained in the printhead.

[0044] In this specification, the term "ink" means any printing fluid that can be printed from an inkjet printhead. Ink may or may not contain colorants. Therefore, the term "ink" may include conventional dye-based or pigment-based inks, infrared inks, fixatives (e.g., precoats and finishers), 3D printing fluids (e.g., binder fluids), functional fluids (e.g., solar inks, sensing inks, etc.), biological fluids, and the like.

[0045] In this specification, the term “attached” includes both direct attachment and indirect attachment via intermediary components. [Brief explanation of the drawing]

[0046] Hereinafter, embodiments of the present invention will be described with reference to the attached drawings, merely as examples. [Figure 1] Figure 1 is a side perspective view of an inkjet printing module. [Figure 2] Figure 2 is a bottom perspective view of the inkjet printing module. [Figure 3] Figure 3 is a front perspective view of the inkjet printing module. [Figure 4] Figure 4 shows the maintenance subassembly of the inkjet printing module. [Figure 5] Figure 5 is a front perspective view of the print head support module. [Figure 6] Figure 6 is a rear perspective view of the print head support module. [Figure 7] Figure 7 is a top perspective view of an inkjet print head. [Figure 8] Figure 8 is a bottom perspective view of the inkjet print head. [Figure 9] Figure 9 is a perspective view of the cradle of the inkjet printing module. [Figure 10] Figure 10 is a top perspective view of the supply assembly of the inkjet printing module. [Figure 11] Figure 11 is an exploded perspective view of the supply assembly shown in Figure 10, with the PCB removed. [Figure 12] Figure 12 is a partial perspective view of the supply assembly shown in Figure 10, with the PCB removed. [Figure 13] Figure 13 shows the access opening at the first end of the inkjet printing module. [Figure 14] Figures 14A to 14C are schematic side views showing the removal of the print head from the rotating print head carrier. [Figure 15] Figure 15 is a perspective view of the print head carrier. [Figure 16] Figure 16 is an end view of the inkjet printhead shown in Figures 7 and 8. [Figure 17] Figures 17A to 17C show various key configurations for the print head carrier key slot assembly. [Figure 18] Figures 18A and 18B show the data paths of an inkjet printhead module with printheads accepted in the first and second printhead directions, respectively. [Figure 19] Figure 19 is a schematic plan view of a printing system having forward-facing and reverse-facing inkjet printing modules. [Modes for carrying out the invention]

[0047] Inkjet printing module Referring to Figures 1 to 3, an inkjet printing module 10 (or “print engine”) as described in U.S. Patent No. 11,014,366 (the contents of which are incorporated herein by reference) is shown. This inkjet printing module 10 is designed as a fully integrated “drop-in” module incorporating a print head mounting structure, ink supply system, maintenance system, print head lift mechanism, etc., enabling OEMs to install the inkjet printing module into an end-user’s printing system with minimal development work.

[0048] As shown in Figure 1, the inkjet printing module 10 comprises a chassis 15 for fixed mounting to the printing system and a printhead support module 17 movably connected to the chassis 15 via a module lift mechanism 19. The inkjet printing module 10 typically incorporates an integrated ink supply system having module ink ports 11 that provide connection to an external ink reservoir (not shown). The integrated ink supply system may include, for example, a pressure regulating tank, a pump, a pinch valve, and circulating fluid loops for each color channel, as described in U.S. Patent No. 10,639,903 (the contents of which are incorporated herein by reference).

[0049] In Figures 1 to 3, the inkjet printing module 10 is shown with the print head support module 17 in its raised (maintenance) position. The module lift mechanism 19 takes the form of a rack and pinion mechanism including a pair of racks 21 mounted on both ends of the back plate 22 of the chassis 15 and a corresponding pair of pinions 23 that engage with the racks, the pair of pinions being fixedly mounted around an interconnecting pinion shaft 25. The module lift mechanism 19 is driven by a lift motor 27, which is operably connected to one of the pinions 23 to move the pair of pinions along the racks via the rotation of the interconnecting pinion shaft 25.

[0050] The pinion shaft 25 is rotatably mounted between a pair of lift brackets 29 that house the respective pinions 23, and the module lift mechanism 19 allows the lift brackets to be lowered or raised. The lift brackets 29 are interconnected via an elongated mounting beam 31 that extends longitudinally along the length of the print engine 10. The top of the print head support module 17 is provided with appropriate mounting fixtures 30 for fixed attachment to the mounting beam 31 (see Figure 5). Thus, the print head support module 17 can be raised and lowered between a maintenance position and a printing position via the operation of a lift motor 27.

[0051] The lower part of the chassis 15 includes an L-shaped frame 32 fixed to the backplate 22. The L-shaped frame 32 houses a maintenance subassembly 33 of the inkjet printing module 10, which is shown separately in Figure 4. The maintenance subassembly 33 includes a capper 35 and a wiper carriage 37 for performing maintenance operations on the elongated inkjet printhead 50 received in the printhead support module 17. The capper 35, housed in the longer arm 39 of the L-shaped frame, is extendable laterally from the backplate 22 of the chassis 15 via a scissor mechanism 40 that caps the printhead 50. The wiper carriage 37, housed in the shorter arm 41 of the L-shaped frame, is traversable along the longitudinal axis of the printhead support module 17 to wipe the printhead 50. In the configuration shown in Figures 1 to 4, the capper 35 is positioned laterally extended with the print head capped, and the wiper carriage 37 is in a stopped or "home" position housed within the shorter arm 41 of the L-shaped frame 32. The maintenance subassembly 33 is similar in both function and mechanism to the maintenance module described in U.S. Patent No. 10,081,204 (the contents of which are incorporated herein by reference). For a more detailed description of the function and mechanism of the maintenance subassembly 33, those skilled in the art should refer to U.S. Patent No. 10,081,204.

[0052] Referring to Figures 5 and 6, the printhead support module 17 is shown in a separated state. The printhead support module 17 is elongated as a whole and primarily serves to detachably mount the printhead cartridge 50 (or “printhead 50”) shown in Figures 7 and 8. This function is described in detail in U.S. Patent No. 10,293,609, which is incorporated herein by reference. Briefly, the printhead 50 includes a first row 102A of print chips and a second row 102B of print chips, each row containing multiple print chips butted end to end in a row. The print chips are mounted on the underside of an ink manifold (not shown in Figures 7 and 8) housed in a two-part housing 104. Ink ports 74 at both ends of the housing function as inlet or outlet ports for the printhead 50, sending ink into longitudinal ink channels (not shown) and enabling the circulation of ink through the printhead. Multiple printhead contacts 103 extend along both sides of the printhead 50 to electrically connect to complementary PCB contacts 101 of the printhead support module 17. The overhead hanger 114 is configured to slide-engage complementaryly with the printhead carrier 112 of the printhead support module 17. Despite the asymmetrical key projection 132 extending from the upper portion of the printhead 50, the printhead has 180-degree rotational symmetry about the centrally located printing axis P parallel to the droplet ejection axis. As a result of this symmetry, the printhead 50 can, in principle, be used in either a first orientation or a second orientation rotated 180 degrees around the printing axis P relative to the first orientation.

[0053] Returning to Figure 5, the print head support module 17 houses first and second opposing PCBs 52A, 52B, a pair of ink couplings 54, and various mechanisms for detachably connecting the PCB contacts 101 and the ink couplings to the print head 50. In particular, the print head support module 17 includes a cradle 56 and a movable supply assembly 60.

[0054] Referring to Figure 9, the cradle 56 comprises a lower nest 57 defining a longitudinal cavity 59 for receiving the printhead 50, front and rear cradle side plates 58 extending upward from the nest, and first and second end housings 78A, 78B fixed to the nest. Each of the first and second end housings 78A, 78B has a foot portion connected to an anchor point 80 of the nest 57 and an upper portion including a fixture 30 for mounting to the mounting beam 31 of the inkjet printing module 10. To allow some tolerance in the module lift mechanism 19 when aligning the printhead supply module 17 to its printing and maintenance positions, an elastic mounting structure 82 is used to attach the end housings 78A, 78B to the anchor point 80.

[0055] The supply assembly 60 is slidably received within the cradle 56 between the front and rear cradle side plates 58, and the supply assembly can be lifted in a direction toward or toward the nest 57 (including the print head 50) by a lever mechanism 62 actuated via a lever handle 90, as described, for example, in U.S. Patent No. 11,014,366.

[0056] Referring to Figures 10 to 13, the supply assembly 60 comprises a pair of front and rear PCB mounting plates 64 extending parallel to the cradle side plate 58. As shown in Figure 10, opposing PCBs 52 are each fixed to their respective PCB mounting plates 64, with space defined between the opposing PCBs. Each PCB 52 has its own PCB contacts 101 (not visible in Figure 10) located on its underside to form electrical connections with the respective print head contacts 103 on either side of the print head 50.

[0057] A fan assembly fixed between two PCB mounting plates 64 comprises a fan 70 and a duct structure 71 that supply airflow to the space between the PCBs 52 to cool various electronic components. Structural rigidity is provided by first and second end brackets 68A, 68B that interconnect the front and rear PCB mounting plates 64.

[0058] Each of the first and second end brackets 68A and 68B has a mounting bracket 69 extending longitudinally outward from there, thereby allowing a set of ink couplings 54 to be mounted via respective ink coupling brackets 72 suspended from the mounting bracket. That is, the ink couplings 54 are attached to the supply assembly 60 and move in cooperation with the PCB 52. At both ends of the supply assembly 60 are two sets of ink couplings 54 corresponding to the ink ports 74 at both ends of the print head 50.

[0059] Two sets of ink couplings 54, ink coupling brackets 72, and mounting shelves 69 located at both ends of the first printing module 17 are housed in the first and second end housings 78A and 78B, respectively, of the cradle 56. The first end housing 78A at the first end of the first printing module 17 is transparent in Figures 5 and 6 so that the ink couplings 54 and associated mounting fixtures are visible.

[0060] As described in U.S. Patent No. 11,014,366, the ink connection to the print head 50 is made by using a lever mechanism 62 to lower the supply assembly 60 along the nominal z-axis. When the supply assembly 60 is in its lowered position, the rows on both sides of the PCB contacts 101 are positioned adjacent to their respective print head contacts 103. The ink and electrical connections between the supply assembly 60 and the print head 50 are formed in separate steps, thereby minimizing the force required to form those connections.

[0061] The first end housing 78A at the first end of the first printing module 17 defines an access opening 110 for longitudinally inserting and removing the print head 50 along the nominal y-axis. The cradle 56 includes a print head carrier 112, which is rotatable about a cradle pivot axis 116 perpendicular to the printing axis P and the longitudinal axis of the print head. When inserting or removing the print head, the print head carrier 112 is rotated so that one end of it, which is close to the access opening 110, is raised to the print head access position.

[0062] Figures 14A to 14C show the basic rotational movement of the printhead carrier 112 for removing the printhead 50. In Figure 14A, the printhead is fully engaged with the printhead carrier and is positioned horizontally within the nest 57 in the printing configuration. In Figure 14B, the printhead 50 is still fully engaged with the printhead carrier 112, but the printhead carrier rotates around the pivot axis 116 at the second end of the nest 57, resulting in the first end of the printhead carrier 112 (and printhead 50) being lifted relative to the second end. In Figure 14C, the printhead 50 is removed from the printhead carrier 112 by sliding it longitudinally away from the printhead carrier.

[0063] As described in U.S. Patent No. 11,014,366, for a single inkjet printing module 10 ("print engine"), the key projections 132 of the print head 50 and the complementary key slots of the print head carrier 112 work together to ensure that the print head slides into the print head carrier 112 in only one preset orientation. However, for a modular configuration using multiple inkjet printing modules 10 in "forward" and "backward" orientations, as described later, the print head carrier 112 includes a configurable key slot assembly 150 that allows the print head to slide into the print head carrier in either of the first or second print head orientations, thereby taking advantage of the inherent rotational symmetry of the print head.

[0064] Cradle and printhead key arrangement Referring to Figures 15, 16, and 17A-17C, a cradle and printhead key arrangement is shown that can be configured to accept the printhead 50 only in a first printhead direction or only in a second printhead direction, through complementary engagement between the fixed printhead key feature section 132 and the configurable key slot assembly 150.

[0065] The key slot assembly 150 comprises first and second key slots 152A and 152B defined at the first end of the print head carrier 112, and a slidable movable shutter 154 for selectively covering one of the key slots. In the first cradle configuration shown in Figure 17A, the shutter 154 covers the first key slot 152A (but not the second key slot 152B) so that the print head 50 can be inserted longitudinally into the print head carrier 112 only in the first print head direction shown in Figure 16. In the second cradle configuration shown in Figure 17B, the shutter 154 slides to cover the second key slot 152B while the first key slot 152A remains open. In this second cradle configuration, the print head carrier 112 cannot receive the print head 50 in the first print head direction. In this second cradle configuration, inserting the print head 50 into the print head carrier 112 requires rotating the print head 180 degrees around the printing axis P so that it faces the second print head, with the key projection 132 being inserted into the open first key slot 152A.

[0066] Finally, as shown in Figure 17C, the shutter 154 is moved to the neutral position, resulting in both the first key slot 152A and the second key slot 152B being open. In this configuration, the print head 50 can be inserted in either the first or second print head direction. While this cradle configuration is useful for testing purposes, it is not typically used in the field.

[0067] In this embodiment, the key projection 132 of the print head 50 and the complementary key slot assembly 150 of the print head carrier 112 have been described with reference; however, it should be understood that complementary key engagement between the print head and the print head carrier can be achieved with any combination of key slots / key projections of either component.

[0068] Switchable data paths Referring to Figures 18A and 18B, the data paths for transmitting print data signals to the print head 50 are shown in a first orientation (Figure 18A) and a second orientation (Figure 18B). The print head 50 is schematically shown in a cross-section viewed from the first end of the inkjet printing module 10 having an access opening 110.

[0069] The onboard controller chip 160 of the inkjet printing module 10 receives print data for each color surface: cyan, magenta, yellow, and black. The print data is typically sent from an external raster image processor (RIP) to the controller chip 10, and in the case of multiple overlapping print heads 50, each controller chip 50 of each inkjet printing module 10 receives print data for its dedicated segment of the image.

[0070] The controller chip 160 distributes the received print data to the print head 50 via the first and second data paths 162A and 162B. The first and second data paths 162A and 162B each include the first and second PCBs 52A and 52B, respectively, and transmit data signals to the print head contacts 103 on both sides of the print head 50 via their respective PCB contacts 101.

[0071] As shown in Figure 18A, the print head 50 is inserted in its first orientation, determined by the position of the key projection 132 as viewed from the first end of the inkjet printing module 10 having the access opening 110. As just one example, the ink channels 164 in the ink manifold 166 of the print head 50 are nominally arranged in the order M, K, C, Y (from the first PCB 52A toward the second PCB 52B), with the first row of print chips 102A printing magenta and black ink (magenta being the leading ink color) and the second row of print chips printing cyan and yellow ink (yellow being the trailing ink color).

[0072] An electrical switch 168 (e.g., a toggle switch) operably connected to the controller chip 160 is nominally open when the print head 50 is in the first orientation shown in Figure 18A. With switch 168 open, the controller chip 160 distributes the magenta and black data signals ("first data signals") to the first data path 162A and the cyan and yellow data signals ("second data signals") to the second data path 162B. Thus, the first and second columns 102A and 102B of the print chip receive the correct data signals corresponding to their respective ink colors.

[0073] Referring to Figure 18B, the print head 50 is inserted into the inkjet printing module 110 in a second orientation, rotated 180 degrees relative to the first orientation, as indicated by the position of the key protrusion 132. In this second print head orientation, the ink channels 164 of the print head 50 are typically arranged in the reverse order of Y, C, K, M (from the first PCB 52A to the second PCB 52B). Thus, the first row 102A of the print chip still prints magenta and black ink, and the second row 102B of the print chip still prints cyan and yellow ink. In practice, changing the arrangement order of the print head 50 is achieved relatively easily by simply reversing the order in which the ink reservoirs are connected to the module ink ports 11.

[0074] Referring further to Figure 18B, the print head 50 is in the second orientation, the arrangement order of the ink channels 164 is reversed, and switch 168 is closed. Closing switch 168 instructs the controller chip 160 to reverse the distribution of the first and second data signals between the first and second data paths. As a result, the controller chip 168 distributes the magenta and black data signals ("first data signals") to the second data path 162B and the cyan and yellow data signals ("second data signals") to the first data path 162A. Thus, the first and second columns 102A and 102B of the print chip still receive the correct data signals for their respective ink colors.

[0075] First, the advantages of configuring the inkjet printing module 10 in this way with respect to the first and second print head directions will become readily apparent from the following description of a modular array having forward-facing modules and reverse-facing modules.

[0076] Modular array Figure 19 schematically shows a printing system 200 including a modular array of inkjet printing modules 10 arranged in a staggered, overlapping configuration across a media feed path 202. In this example, the printing system 200 includes a pair of inkjet printing modules, with a second inkjet module 10B following a first inkjet module 10A in the media feed direction indicated by arrow D. However, it should be understood that, naturally, any number of inkjet modules 10 can be arranged across the media path 202 to print on various media widths. For example, the printing system 200 may have two preceding inkjet printing modules and one succeeding inkjet printing module in a 3-width array. Other module arrangements will also be readily apparent to those skilled in the art.

[0077] As shown in Figure 19, the subsequent second inkjet printing module 10B is rotated 180 degrees relative to the first inkjet printing module 10A. Since the print heads 50 are positioned asymmetrically toward one side of each inkjet printing module 10, this arrangement ensures that the print heads 50 of the preceding and succeeding inkjet printing modules 10A and 10B are positioned as close together as possible along the media feed direction D. This close positioning of the print heads 50 is advantageous because it minimizes alignment errors, resulting in improved print quality, especially in areas where the modules overlap.

[0078] As a result of the second inkjet printing module 10B being rotated 180 degrees relative to the first inkjet printing module 10A, it will be understood that the cappers 35 of each of the first and second inkjet printing modules will inevitably move toward each other in opposite directions parallel to the media feed direction D in order to cap their respective print heads 50. Similarly, the wiper carriages 37 of each of the first and second inkjet printing modules will inevitably move toward each other in directions perpendicular to the media feed direction D in order to wipe their respective print heads 50.

[0079] As described above, the module ink ports 11 of the first and second inkjet printing modules 10A and 10B are connected to their respective ink reservoirs (not shown) in such a way that they maintain the same order of ink colors with respect to the media feeding direction D (nominally, the order M, K, C, Y in the printing system 200 shown in Figure 19). For this reason, the module ink ports 11 of the second inkjet printing module 10B are connected in the reverse order to the module ink ports of the first inkjet printing module 10A.

[0080] The inversion of the ink arrangement in the second inkjet printing module 10B maintains the order of ink colors relative to the media feed direction D, while inserting the printhead 50 into the second inkjet printing module 10B in its second printhead direction (as shown in Figure 19 and as described above in relation to Figure 18B) makes it possible to use all printheads in the printing system 200 interchangeably. Thus, the printhead 50 in the first printhead direction in the first inkjet printing module 10A can be inserted into and removed from the second inkjet printing module 10B in its second printhead direction without mixing ink colors and without reconfiguring the printing system 200.

[0081] Furthermore, each factory-manufactured inkjet printing module 10 can be easily converted for use in either forward or reverse orientation simply by moving the shutter 154 and appropriately configuring the switch 168. Essentially, each inkjet printing module 10 is independent of its orientation of use, offering a significant advantage compared to printing systems that require dedicated forward and reverse modules with different mechanical designs.

[0082] Naturally, the present invention is described merely as an example, and it should be understood that modifications of details are possible within the scope of the invention as defined in the appended claims.

Claims

1. Inkjet printing module, A printhead comprising first and second rows of print chips, having 180 degrees of rotational symmetry about a printing axis parallel to the droplet ejection direction, A cradle for removably receiving the print head, The inkjet printing module includes a control circuit for distributing data signals to the print head via first and second data paths, The cradle can be configured to receive the print heads in first and second print head directions relative to the printing module, wherein the second print head direction is rotated 180 degrees around the printing axis with respect to the first print head direction. The inkjet printing module is characterized in that the control circuit can be configured to invert the distribution of data signals between the first data path and the second data path.

2. In the inkjet printing module according to claim 1, An inkjet printing module characterized in that the first and second rows of the print chips have 180 degrees of rotational symmetry around the printing axis.

3. In the inkjet printing module according to claim 1, An inkjet printing module characterized in that the cradle comprises a configurable key slot assembly for complementary engagement with a fixed print head key feature portion, and the cradle is configured such that the key slot assembly accepts the print head in either the first print head direction or the second print head direction only.

4. In the inkjet printing module according to claim 3, An inkjet printing module characterized in that the fixed print head key feature portion is rotationally asymmetrical about the printing axis, regardless of the rotational symmetry of the print head.

5. In the inkjet printing module according to claim 1, An inkjet printing module characterized in that the print head has a plurality of print head ink ports at both ends thereof, and the inkjet printing module has complementary ink couplings for detachably connecting to the print head ink ports.

6. In the inkjet printing module according to claim 5, An inkjet printing module further comprising a plurality of module ink ports for connecting to a plurality of corresponding ink reservoirs that supply ink to the ink coupling, wherein each module ink port is connectable to any one of the plurality of ink reservoirs such that the order in which ink is supplied to the printhead ink port can be reversed.

7. In the inkjet printing module according to claim 1, An inkjet printing module further comprising a switch operably connected to the control circuit for inverting the distribution of the aforementioned data signals.

8. In the inkjet printing module according to claim 1, The inkjet printing module is characterized in that the control circuit includes a controller chip configured to receive print data and distribute data signals between the first data path and the second data path.

9. In the inkjet printing module according to claim 1, An inkjet printing module characterized in that the first and second data paths include first and second module contacts, respectively, and each of the first and second module contacts is configured to be electrically connected to either the first or second printhead contact in either the first or second printhead direction.

10. In the inkjet printing module according to claim 1, An inkjet printing module characterized in that the print head is arranged asymmetrically toward one side of the inkjet printing module.

11. In the inkjet printing module according to claim 1, Printed head cappers, Printhead wiping system, and A lift mechanism for raising and lowering the print head relative to the media path, An inkjet printing module characterized by further comprising one or more of the following.

12. A printing system comprising a plurality of inkjet printing modules as described in claim 1, The plurality of inkjet printing modules, A first inkjet printing module disposed on the media path in a first module direction with respect to the media path, the first inkjet printing module comprising print heads received in their respective cradles in a first print head direction with respect to the first printing module such that a first row of print chips of the first printing module is upstream of a second row of print chips, A second inkjet printing module is arranged on the media path in a second module direction rotated 180 degrees with respect to the first module direction, and the second printing module comprises print heads received in their respective cradles in a second print head direction relative to the second printing module such that the first row of print chips of the second printing module is downstream of the second row of print chips, The data signals corresponding to the first color plane are distributed only through the first data path of the first printing module. A printing system characterized in that the data signals corresponding to the first color plane are distributed only through the second data path of the first printing module.

13. In the printing system according to claim 12, A printing system characterized in that the first and second inkjet printing modules are arranged to cross the media feed path in a staggered arrangement, such that the first and second print heads overlap.

14. In the printing system according to claim 12, A printing system characterized in that ink is supplied to each print head such that the ink sequence in the first and second rows of print chips relative to the media path is the same in both the first and second inkjet printing modules.

15. In the printing system according to claim 14, A printing system characterized in that each row of print chips can be configured to print two colors of ink.

16. In the printing system according to claim 12, A printing system characterized in that a print head that has been soiled with ink and removed from the first or second inkjet printing module is replaceable in either the first or second inkjet printing module.

17. In the printing system according to claim 12, A printing system characterized in that a first switch operably connected to the control circuit of the first inkjet printing module is deactivated, and a second switch operably connected to the control circuit of the second inkjet printing module is activated, thereby causing the second switch to invert the data signals distributed to the first inkjet printing module via the first and second data paths of the second inkjet printing module.

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