Mounting assembly for mounting a plurality of inkjet print modules

Abstract

A mounting assembly (1) for mounting a plurality of inkjet print modules in an adjoining relationship along a longitudinal direction of the mounting assembly (1) comprises a linear guide (13, 14) extending in the longitudinal direction for supporting the plurality of modules such that the modules are movable along the linear guide (13, 14). It further comprises for each of the plurality of modules a carrier (100.1 . . . 4) for mounting an inkjet print head including an array of nozzles formed on a nozzle face, wherein the carriers (100.1 . . . 4) are supported on the linear guide (13, 14) such that they are movable along the linear guide (13, 14), wherein in a mounted configuration of the inkjet print heads their nozzle face is arranged on a first side of the linear guide (13, 14). Each carrier (100.1 . . . 4) comprises a first adjustment mechanism for adjusting a distance of the carriers 100.1 . . . 4) of two adjoining modules of the plurality of modules, the first adjustment mechanism comprising a first control member having an operating section for mechanically cooperating with a tool for adjusting the distance. Each carrier (100.1 . . . 4) further comprises a second adjustment mechanism for adjusting an angle position of the inkjet print head mounted to the carrier (100.1 . . . 4) with respect to an axis perpendicular to the longitudinal direction, the second adjustment mechanism comprising a second control member having an operating section for mechanically cooperating with a tool for adjusting the angle position. The operating sections of the control members of the first and of the second adjustment mechanism are accessible from the first side of the linear guide (13, 14).

Claims

1. Mounting assembly for mounting a plurality of inkjet print modules in an adjoining relationship along a longitudinal direction of the mounting assembly, comprising a) a linear guide extending in the longitudinal direction for supporting the plurality of modules such that the modules are movable along the linear guide; b) for each of the plurality of modules a carrier for mounting an inkjet print head including an array of nozzles formed on a nozzle face on a nozzle face side of the print module, wherein the carriers are supported on the linear guide such that they are movable along the linear guide; c) wherein at least one of the carriers comprises a first adjustment mechanism for adjusting a distance of the carriers of two adjoining modules of the plurality of modules, the first adjustment mechanism comprising a first control member having an operating section for mechanically cooperating with a tool for adjusting the distance; d) wherein at least one of the carriers further comprises a second adjustment mechanism for adjusting an angle position of the inkjet print head mounted to the carrier with respect to an axis perpendicular to the longitudinal direction, the second adjustment mechanism comprising a second control member having an operating section for mechanically cooperating with a tool for adjusting the angle position; wherein the operating sections of the control members of the first and of the second adjustment mechanism are accessible from the nozzle face side of the print module.

2. Mounting assembly according to claim 1, wherein the control members are screws and the operating sections are screw heads.

3. Mounting assembly according to claim 2, at least one of the screws comprising a fine thread.

4. Mounting assembly according to claim 1, wherein the linear guide comprises two longitudinal rails and in that the carriers are slidably mounted on the rails.

5. Mounting assembly according to claim 4, wherein the rails comprise a mechanism for maintaining a predetermined temperature.

6. Mounting assembly according to claim 1, wherein the carriers are mounted to the linear guide in such a way that the plurality of carriers are urged against a first end of the linear guide, whereas the first adjustment mechanisms allow for adjusting the mutual distance of the carriers of two adjoining modules.

7. Mounting assembly according to claim 6, wherein a compression spring acts onto an outermost carrier opposite the first end of the linear guide for urging the plurality of carriers against the first end.

8. Mounting assembly according to claim 1, wherein the first adjustment mechanism comprises a first wedge element contacting two adjoining carriers, wherein a position of the first wedge element is adjustable by operating the first control member.

9. Mounting, assembly according to claim 8, wherein a lever cooperates with the first control member and the first wedge element.

10. Mounting assembly according to claim 1, wherein the second adjustment mechanism comprises a second wedge element mechanically coupled to the second control member for adjusting the angle position.

11. Mounting assembly according to claim 10, wherein the carrier comprises a rotatable mount for the inkjet print head, the rotatable mount having a projecting element cooperating with the second wedge element.

12. Inkjet printer comprising a) at least one mounting assembly according to claim 1; b) an adjusting robot comprising a tool for cooperating with the operating sections of the control members of the first and of the second adjustment mechanism, the robot being arranged on the nozzle face side of the print modules supported by the linear guide.

13. The inkjet printer according to claim 12, wherein the adjusting robot selectively cooperates with a single one of the inkjet print heads, wherein the adjusting robot is movable along the longitudinal direction.

14. The inkjet printer according to claim 12, wherein the adjusting robot comprises a drive for rotatably operating the tool.

15. The inkjet printer according to claim 12, wherein the adjusting robot comprises an adjusting section comprising the tool and a cleaning section comprising a device for cleaning the array of nozzles of the inkjet print head mounted on a carrier in a cooperating position with the adjusting robot.

16. The inkjet printer according to claim 15, wherein the adjusting robot comprises a first operating configuration in which the adjusting section is in cooperating position with one of the plurality of carriers and a second operating configuration in which the cleaning section is in cooperating position with the array of nozzles of the inkjet print head mounted to the carrier.

17. The inkjet printer according to claim 15, wherein the device for cleaning comprises at least one lip for cooperating with the array of nozzles of the inkjet print head and least two nozzles for ejecting a cleaning agent and a rinsing solution, respectively.

18. Mounting assembly according to claim 1, wherein a mounted configuration of the inkjet print heads their nozzle face being arranged on a first side of the linear guide and wherein the operating sections of the control members of the first and of the second adjustment mechanism are accessible from the first side of the linear guide.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The drawings used to explain the embodiments show:

(2) FIG. 1 An oblique view of a mounting assembly according to the invention;

(3) FIG. 2 an oblique view of the mounting assembly with print heads installed;

(4) FIG. 3A an oblique view of a carrier of the mounting assembly with the mechanism for the adjustment of the distance to an adjoining carrier;

(5) FIG. 3B an oblique view of the wedge element of the mechanism;

(6) FIG. 4 an oblique view of the print head with an interfacing element for supporting the print head in the carrier;

(7) FIG. 5A an oblique view of the carrier of the mounting assembly with the mechanism for the adjustment of the angular position of the print head;

(8) FIG. 5B an oblique view of the wedge element of the mechanism;

(9) FIG. 6 an oblique view of an adjusting and cleaning robot according to the invention;

(10) FIG. 7 a side view of the adjusting and cleaning robot;

(11) FIG. 8A a bottom view of two print modules in a basic position;

(12) FIG. 8B an oblique view of the carrier of one of the modules in the basic position;

(13) FIG. 9A a bottom view of two print modules, where one of the print modules is angularly displaced with respect to the other print module;

(14) FIG. 9B an oblique view of the carrier of the angularly displaced module;

(15) FIG. 10A a bottom view of two print modules with an increased mutual distance;

(16) FIG. 10B an oblique view of the carrier of one of the modules with increased distance;

(17) FIG. 11A a bottom view of two print modules with an reduced mutual distance; and

(18) FIG. 11B an oblique view of the carrier of one of the modules with reduced distance.

(19) In the figures, the same components are given the same reference symbols.

PREFERRED EMBODIMENTS

(20) An embodiment of the invention is described in connection with FIGS. 1-11. FIG. 1 is an oblique view of a mounting assembly according to the invention, FIG. 2 shows the mounting assembly with print heads installed. The mounting assembly 1 comprises a frame 10 including two basically rectangular plate shaped side parts 11, 12, which are arranged parallel to each other in a distance. The lower regions of the side parts 11, 12 are connected by two parallel rails 13, 14. Four carriers 100.1, 100.2, 100.3, 100.4 are supported on the rails 13, 14. The carriers 100.1 . . . 4 are described in more detail below, in connection with FIGS. 3-5.

(21) Adjoining carriers 100.1 . . . 4 contact each other, they are urged to one of the side plates 11 by a compression spring 16 which are supported on the rails 13, 14 adjoining the other side plate 12 and which contact the first carrier 100.1.

(22) In each of the carriers 100.1 . . . 4 a print head 20.1 . . . 4 is supported. The mounted print heads 20.1 . . . 4 are accommodated in a space defined by the two side parts 11, 12 of the mounting assembly 1. In a manner known as such, the print heads 20.1 . . . 4 inter alia comprise an ink nozzle array and are components of print modules that comprise further components for feeding and preconditioning ink and controlling the ejection of the ink by the ink nozzle array. In the mounted configuration of the print heads 20.1 . . . 4, the ink nozzle array is positioned on a first side of the carriers 100.1 . . . 4 (below in the view shown in FIG. 2), whereas the other components of the print heads 20.1 . . . 4 are positioned on a second side of the carriers 100.1 . . . 4, which is opposite to the first side (above the carriers 100.1 . . . 4 in the view shown in FIG. 2). The two rails 13, 14 are provided with a duct that is part of a heat exchanging fluid circuit. This ensures that the rails 13, 14 and the carriers 100.1 . . . 4 may be held at a predetermined temperature, thus minimizing thermal effects on the geometry of the mounting assembly.

(23) An inkjet printing device may include a single or several mounting assemblies with print heads installed. The number of print heads in a mounting assembly may be below or above 4 (e. g. 2, 3 or 6).

(24) Further elements will be attached to the mounting assembly, namely a manifold for the distribution of ink to the different print modules, electronic components for controlling the printing operation and a housing enclosing the different components.

(25) The FIG. 3A is an oblique view of a carrier 100 of the mounting assembly with the mechanism for the adjustment of the distance to an adjoining carrier. The FIG. 3B is an oblique view of the wedge element of the mechanism. It is to be noted that of the four carriers 100.1 . . . 4 shown in the FIGS. 1 and 2, only three of them, namely carriers 100.2 . . . 100.4, include such a mechanism as in order to enable seamless printing it is sufficient to adjust the mutual distance of adjoining carriers 100.1 . . . 4, i. e. three distances.

(26) The mechanism 110 includes an adjustment screw 111 with a fine thread, the lower part of which is supported in a vertical bore 102 of a base body 101 of the carrier 100. A screw head of the adjustment screw 111 is situated below the base body 101 and includes a hexagon socket. The upper part of the adjustment screw 111 cooperates with a bore 113 of a link element 112 (cf. also FIG. 8B). A lever 114 is pivotally supported on a pillar 115 of the base body 101, its pivoting axis runs parallel to a main plane of the base body 101 of the carrier 100. One end of the lever 114 is linked to the link element 112, the other end of the lever 114 is linked to a wedge element 116. If the link element 112 is lowered by corresponding action of the adjustment screw 111, the wedge element 116 is raised due to action of the lever 114 and vice versa (cf. also FIG. 8B).

(27) The wedge element 116 as shown in FIG. 3B comprises a yoke 116a linking two legs 116b, 116c. Starting from the yoke 116a, a thickness of the legs 116b, 116c decreases. The wedge element 116 contacts the base body of the adjoining carrier. Due to the geometry of the legs 116b, 116c, the distance between the adjoining carriers is reduced if the wedge element 116 is raised, and the distance between the adjoining carriers is increased if the wedge element 116 is lowered.

(28) The base body 101 further comprises two through bores 121, 122 running parallel to each other and parallel to the main plane of the base body 101. In the mounted configuration of the carrier 100 they cooperate with the rails 13, 14 of the mounting assembly 1. Finally, the base body 101 comprises a central opening 125 for accommodating the print head (cf. FIG. 4).

(29) The FIG. 4 is an oblique view of the print head 20 with an interfacing element 30 for supporting the print head 20 in the carrier. The print head 20 is firmly glued to the interfacing element 30. The latter comprises a base part 31 having a central opening for accommodating the print head 20 as well as an upper part 32 having an arcuate outer shell surface, a rotational symmetry axis standing perpendicular to a main surface of the base part 31 and a positioning pin 33 protruding perpendicular to the outer shell surface.

(30) The print head 20 being firmly glued to the interfacing element 30, the rotational symmetry axis of the outer shell surface of the upper part 32 is exactly perpendicular to the plane defined by the nozzle array of the print head 20. In the installed configuration, the interfacing element 30 cooperates with the carrier 100, in particular with the central opening 125 of the carrier. For that purpose, in order to ensure precise positioning of the print head, the outer shell surface of the interfacing element 30 is precisely adapted to the geometry of the opening 125.

(31) The FIG. 5A is an oblique view of the carrier of the mounting assembly with the mechanism for the adjustment of the angular position of the print head. The FIG. 5B is an oblique view of the wedge element of the mechanism. In contrast to the mechanism for adjusting the mutual distance between adjoining carriers, all the carriers 100.1 . . . 4 comprise such a mechanism for adjusting the angular position as such adjustment may be required for any of the print heads.

(32) The mechanism 130 includes an adjustment screw 131 with a fine thread, the lower part of which is supported in a further vertical bore 103 of the base body 101 of the carrier 100. A screw head of the adjustment screw 131 is situated below the base body 101 and includes a hexagon socket. The upper part of the adjustment screw 131 cooperates with a bore 133 of a wedge element 132.

(33) As shown in FIG. 5B, the wedge element 132 comprises an outer guide surface 132a which cooperates with a fixed pillar 134 of the base body 101 of the carrier 100. Opposite to the guide surface 132a, the wedge element 132 comprises a generally planar wedge surface 132b, the distance of which increasing from top to bottom (cf. also FIGS. 9B, 10B). The pillar 134 of the base body 101 ensures that a rotational position of the wedge element 132 is constant, independent from the position of the adjustment screw 131. Nevertheless, by rotating the adjustment screw 131, the vertical position of the wedge element 132 may be adjusted.

(34) The wedge surface 132b of the wedge element 132 cooperates with the positioning pin 33 of the interfacing element 30 accommodated in the central opening 125 of the carrier 100. Opposite to the wedge element 132, the positioning pin 33 contacts an elastic element 135 which is mounted on a pin 136 fixedly attached to the base body 101 of the carrier 100. The position of the positioning pin 33 and thus the angular position of the print head glued to the interfacing element 30 are always precisely defined by the height of the wedge element 132. Lowering the wedge element 132 by a corresponding rotation of the adjustment screw 131 corresponds to a slight clock-wise rotation (seen from above) of the interfacing element 30, rising the wedge element 132 corresponds to a slight anti-clock-wise rotation.

(35) The FIG. 6 is an oblique view of an adjusting and cleaning robot according to the invention cooperating with a print bar comprising an assembly similar to the one as described above, in connection with FIGS. 1-5. The main difference is the number of print heads which is 6 instead of 4. The FIG. 7 is a side view of the adjusting and cleaning robot. The robot 200 includes a positioning system 210 and a head 230 that may be positioned along two Cartesian axes, namely the longitudinal axis X, a further horizontal axis Y that is perpendicular to X, and about a rotational axis A (parallel to direction Y) by the positioning system 210.

(36) The positioning system 210 comprises a first linear guide 211, a carriage 212 being supported on two rails 213 of the linear guide 211. The carriage 212 cooperates with a spindle 214 which is driven by a servo motor 215 in such a way that the carriage 212 may be positioned along the rails 213 in X direction.

(37) The carriage 212 carries a second linear guide 216 provided with a guide rail 217 and a spindle 218 operated by a further servo motor 219. Furthermore, a guide block 220 is attached to the carriage 212. A further carriage 221 is supported on the guide rail 217 of the first carriage 212 and may be positioned in Y direction by means of the servo motor 219 and the spindle 218. A rotatable shaft 222 is rotatably supported on the further carriage 221 and rotatably and slidably supported on the guide block 220. A further servo motor 223 supported on the further carriage 221 is coupled to the rotatable shaft 222 and allows for rotating the shaft about a rotation axis A parallel to direction Y.

(38) The head 230 of the robot 200 is coupled to the opposite end of the rotatable shaft 222. It comprises at one of its free ends an adjusting unit 231 having a drive motor 232 coupled to a hexagonal tool head 233. The tool head 233 extends into a direction perpendicular to the rotation axis A. At the opposite free end, the head 230 comprises a cleaning unit 234.

(39) The cleaning unit 234 comprises two nozzles that are connected to supplies for a cleaning agent and a rinsing solution, respectively. It further comprises a wiper that may interact with the nozzle arrays in order to distribute or wipe off the cleaning agent and the rinsing solution, respectively. It may comprise further components such as a nozzle for ejecting pressurized air, etc.

(40) Using the servo motors 215, 217, 223 the head 230 may be positioned along the X and Y directions, furthermore, the head may be rotated about the rotation axis A. This allows for selectively positioning the adjusting unit 231 or the cleaning unit 234 and a cooperating relationship with the adjustment screws of any of the carriers of the mounting assembly or the nozzle array of any of the print heads, respectively.

(41) The FIGS. 8-11 show different positions of two adjoining print heads and the corresponding configurations of the mechanisms for adjusting the mutual distance and the angular position of the heads. The FIGS. 8A, 9A, 10A, 11A show a bottom view of the two print heads mounted to the mounting assembly according to the invention. They show the two rails 13, 14 supporting the carriers 100 of the two print heads. The print heads 20.2, 20.3 are affixed to the carriers 100, the nozzle arrays 21.2, 21.3 of the print heads 20.2, 20.3 are visible. The bottom surfaces of the print heads 20.2, 20.3 as well as the nozzle arrays 21.2, 21.3 are both rhomboid shaped, the nozzle arrays 21.2, 21.3 being slightly slanted with respect to a longitudinal axis which runs parallel to the two rails 13, 14. This allows for having a seamless transition between the two adjoining modules.

(42) The position of one of the modules may be adjusted by operating the screw head of the adjustment screw 111 for the mutual distance, and the screw head of the adjustment screw 131 for the rotational position. Both screw heads are directly accessible from the bottom surface of the carrier 100.

(43) The FIGS. 8B, 9B, 10B, 11B show oblique views of the carrier of one of the modules in the different positions depicted in FIGS. 8A, 9A, 10A, 11A: In FIG. 8A, B, the basic position is shown; FIG. 9A, B shows an angularly displaced module, FIG. 10A, B relates to two modules with increased distance and FIG. 11A, B to two modules with reduced distance.

(44) As can be seen from FIG. 8B, which relates to the basic position, the position of the link element 112 and of the wedge element 132 are both at about half the height of the upper portion of the respective adjustment screw 111, 131 supported in the base body 101 of the carrier 100. Accordingly, the wedge element 116 is at about half its maximum height, controlled via the lever 114 supported on the pillar 115 of the base body 101. Similarly, the positioning pin 33 controlling the angular position of the print head is also at about a middle position. Its exact position is determined by the position of the wedge element 132 and the elastic element 135 mounted on the fixed pin 136 of the base body 101. Due to the fine threads, the two adjustment screws 111, 131 are self locking, i. e. it is sufficient to rotate the screws until the print heads attain their desired position and orientation, no step to lock that position is required.

(45) In the situation shown in FIGS. 9A, 9B and compared to the situation shown in FIGS. 8A, 8B, the angular position of the left print head 20.2 is rotated slightly in the anti-clockwise direction (seen from the bottom). This is achieved by rotating the adjustment screw 131 in such a way that the wedge element 132 is lowered. The portion of the wedge element 132 having a smaller cross-section will thus interact with the positioning pin 33. Due to the elastic force exerted by the elastic element 135 it is ensured that the positioning pin 33 is firmly supported against the wedge element 132. The adjustment screw 131 and its fine thread is designed in such a way that the shown situation is reached if the screw is rotated 7.8 rotations in the clock-wise direction. The resulting angle is 0.437.

(46) In the situation shown in FIGS. 10A, 10B and compared to the situation shown in FIGS. 8A, 8B, the distance of the two adjoining print heads 20.2, 20.3 is increased by 0.200 mm. This is achieved by rotating the adjustment screw 111 about 9.5 rotations in anti-clockwise direction. This causes the height of the link element 112 to increase and consequently the height of the wedge element 116 to decrease. A section of the wedge element 116 having an increased cross-section will thus cooperate with the two base bodies of the carriers and thus increase the distance between the two print heads 20.3, 20.4.

(47) In the situation shown in FIGS. 11A, 11B and compared to the situation shown in FIGS. 8A, 8B, the distance of the two adjoining print heads 20.2, 20.3 is decreased by 0.200 mm. This is achieved by rotating the adjustment screw 9.5 rotations in clockwise direction. This causes the height of the link element 112 to decrease and consequently the height of the wedge element 116 to increase. A section of the wedge element 116 having a decreased cross-section will thus cooperate with the two base bodies of the carriers and thus decrease the distance between the two print heads 20.3, 20.4 to the minimum.

(48) Adjustments may be caused by independently rotating the two adjustment screws 111, 131. This allows for precisely adjusting the position of the nozzle arrays 21.2, 21.3. The re-adjustment of the position of one of the print heads, especially the re-adjustment of the mutual distance of adjoining heads does not require a complete re-adjustment of the mutual distances between other pairs of adjoining heads, because the further heads will keep their relative positions and the change in the total length of the succession of heads is balanced by a slightly changed compression of the spring.

(49) The invention is not limited to the embodiment described above. In particular, the adjustment mechanisms of the carriers may be constructed in a different way. The same applies to the linear guide for supporting the carriers. The adjusting and cleaning robot may as well be embodied differently. In particular, the number of degrees of freedom provided by its positioning system may be different, and the corresponding axes may be provided by different mechanisms. The cleaning unit may be arranged next to the adjusting unit, on the same side of the head of the robot, or it may lack completely.

(50) In summary, it is to be noted that the invention provides a mounting assembly for mounting a plurality of inkjet print modules that is cost-efficient and lightweight and that allows for precise adjustment of the positions of the inkjet print heads of the print modules.