Abstract
A device for adjusting a printing head includes a step-by-step switching mechanism, an actuator for shifting the step-by-step switching mechanism, and a locking disk supported for rotation. A first shifting tongue is provided for incrementally rotating the locking disk in a first direction of rotation. The first shifting tongue has two elongated holes for guidance purposes, one of which has a lateral recess. It is thus possible to adjust printing heads with a high degree of accuracy while saving time and costs. The device is preferably implemented in industrial inkjet printing.
Claims
1. A device for adjusting a printing head, the device comprising: a step-by-step switching mechanism; an actuator for shifting said step-by-step switching mechanism; a rotatably supported locking disk; and a first shifting tongue for incrementally rotating said locking disk in a first direction of rotation, said first shifting tongue having two elongated holes for guidance, one of said elongated holes having a lateral recess.
2. The device according to claim 1, which further comprises a second shifting tongue for incrementally rotating said locking disk in a second direction of rotation opposite the first direction of rotation, said second shifting tongue having two elongated holes for guidance, one of said elongated holes having a lateral recess.
3. The device according to claim 2, wherein said two elongated holes having said lateral recess acting to allow a lateral compensation movement of a respective shifting tongue (31, 31a, 31b, 31c, 31d).
4. The device according to claim 2, wherein said two elongated holes having said lateral recess are mirror-symmetrical to one another.
5. The device according to claim 2, wherein said first shifting tongue or said second shifting tongue carries out a forward movement as a shifting movement and a return movement in an opposite direction.
6. The device according to claim 5, wherein said first shifting tongue or said second shifting tongue shifts said locking disk in a form-locking way in said shifting movement.
7. The device according to claim 6, wherein said first shifting tongue or said second shifting tongue grazes said locking disk in a frictionally engaging way in said return movement.
8. The device according to claim 5, which further comprises a block or a brake associated with said locking disk for preventing at least one of any uncontrolled shifts of said locking disk or any shifts caused by said return movement of said shifting tongues.
9. The device according to claim 1, which further comprises spring elements each associated with a respective one of every shifting tongue for disengaging said respective shifting tongue, in an unactuated state, from a respective locking disk.
10. The device according to claim 1, which further comprises a transmission translating an actuating movement of said locking disk into a corrective movement of the printing head.
Description
BRIEF DESCRIPTION OF THE FIGURES
[0029] FIG. 1 is a fragmentary, diagrammatic, perspective view of a preferred exemplary embodiment of a print bar of a printing unit according to the invention;
[0030] FIG. 2 is a perspective view of a preferred exemplary embodiment of two step-by-step switches;
[0031] FIG. 3 is a side-elevational view of the same preferred exemplary embodiment of two step-by-step switching mechanisms shown in FIG. 2 in an unactuated state;
[0032] FIG. 4 is a view similar to FIG. 3 of the two step-by-step switch mechanisms in an actuated state;
[0033] FIG. 5 is a fragmentary, side-elevational view of a preferred exemplary embodiment of a shifting tongue;
[0034] FIG. 6 is a vertical-sectional view of a preferred exemplary embodiment of a transmission; and
[0035] FIG. 7 is a perspective view showing details of a preferred exemplary embodiment of an inkjet printing machine for printing on a printing substrate such as a web of paper.
DETAILED DESCRIPTION OF THE INVENTION
[0036] Referring now in detail to the figures of the drawings, in which corresponding features have the same reference symbols and repetitive reference symbols have sometimes been left out for reasons of visibility, and first, particularly, to FIG. 1 thereof, there is seen a perspective view of a preferred exemplary embodiment of a print bar of a printing unit of the invention (for instance a printing unit 3 of an inkjet printing machine 1, as seen in FIG. 7). A print bar 4, which is preferably disposed to be stationary, includes a crossbar 4a. A plurality of neighboring printing heads 5 is disposed in a row 7 on the crossbar. Every printing head is disposed in a respective printing head mount 8 in a guide 9 and includes a nozzle surface 5a (see also FIG. 2, for example). Ink is supplied to the printing heads 5, preferably in a circulatory manner, for instance by using illustrated lines 6. The inkjet printing machine 1 further includes a computer 12, preferably a digital computer for controlling the adjustment process.
[0037] FIG. 1 further illustrates an adjustment device 20 for adjusting/orienting the individual printing heads 5. The adjustment device 20 includes a plurality of step-by-step switches 21 disposed adjacent to one another/in a row, each including a first step-by-step switching mechanism 21a and a second step-by-step switching mechanism 21b. FIGS. 2 to 6 illustrate details of the step switching units, which will be explained in more detail in the context of these figures.
[0038] Like every printing bar, the printing bar 4 shown in FIG. 1 is assigned a cleaning device 10 movable back and forth in a direction 53 to clean the printing heads on printing bar 4, which is preferably disposed to be stationary. During a printing operation, the cleaning device 10 is in a stand-by position (illustrated on the right-hand side of FIG. 1). In the cleaning mode, the cleaning device 10 is in a cleaning position (illustrated on the left-hand side in FIG. 1). In the representation of FIG. 1, the cleaning device 10 is in an intermediate position. The cleaning itself is not part of the invention. At least one jointly movable actuator 22, preferably a pneumatically operated actuator, is disposed on the movable cleaning device 10. A drive motor 11 is provided to move the cleaning device(s) 10, as seen in FIG. 7.
[0039] FIG. 2 is a perspective view of a preferred exemplary embodiment of two step-by-step switches: namely of a first step-by-step switching mechanism 21a and a second step-by-step switching mechanism 21b. Every one of the two step-by-step switches includes an incrementally rotatable locking disk 30. Every one of the two step-by-step switches further includes two shifting tongues 31, which are preferably movable in a vertical direction and individually actuatable: a first shifting tongue 31a, a second shifting tongue 31b, a third shifting tongue 31c, and a fourth shifting tongue 31d. Transmissions 40a and 40b with gearwheels 41 and/or tapered spindles 42, for example, are assigned to the step-by-step switches 31 to translate the respective shifting movement into a corrective movement of the printing heads.
[0040] Every shifting tongue 31 preferably includes a protrusion 32 (see FIG. 5), which interacts with the locking disk 30 or rather the locking elements thereof in the shifting operation. Every shifting tongue 31 further includes a first elongated hole 33 and a second elongated hole 34. The first elongated hole 33 (e.g. the upper one) has a lateral recess 35. In cooperation with pins 36, the two elongated holes make the movement possible and limit it at the same time. In an unactuated state, the respective shifting tongues 31 are preferably located in a lower position into which they are pressed by a respective spring element 37. In an actuated state, the respective shifting tongues 31 are preferably in an upper position wherein the locking disk 30 is rotated one locking element further. A pressure element 38 prevents the locking disk 30 from rotating in an undesired way; alternatively, a spring plate may be provided, for instance.
[0041] FIG. 3 is a side view of the same preferred exemplary embodiment of two step-by-step switching mechanisms in an unactuated state, while FIG. 4 is a side view of the same preferred exemplary embodiment of two step-by-step switching mechanisms in an actuated state. A comparison of FIGS. 3 and 4 reveals that the two actuated shifting tongues 31a and 31c have moved upward/are located in an upper position whereas the two unactuated shifting tongues 31b and 31d are located in a lower position.
[0042] FIG. 5 is a side view of a preferred exemplary embodiment of a shifting tongue. For actuation purposes, a change in the position of the cleaning device 10 causes the actuator 22 to move into position, i.e. into a position opposite one of the shifting tongues 31, where it is then preferably actuated by the computer 12 to carry out a movement in a direction 55. In this process, the actuator contacts the respective shifting tongue 31, for example tongue 31a, and moves the latter in accordance with the configuration of the first elongated hole 33 and of the second elongated hole 34. Accordingly, the shifting tongue 31 carries out a movement in a direction 56: either a forward movement 58 (as the shifting movement; in the illustrated example, this is an upward movement) or a return movement 59 (in the illustrated example, this is a downward movement). In the shifting movement, a lateral compensation movement of the shifting tongue is made possible by the lateral recess 35. When a shifting operation is carried out with the shifting tongue 31a, the protrusion 32 preferably rotates the locking disk 30 in a first direction of rotation 54a; in contrast, when a shifting operation is carried out with shifting tongue 31b, the protrusion 32 preferably rotates the locking disk 30 in an opposite, second direction of rotation 54b.
[0043] FIG. 6 is a sectional view of a preferred exemplary embodiment of a transmission. The figure shows a tapered spindle 42, which translates the rotary movement provided by the locking disk 30 (and potentially gearwheels connected in between) into a corrective movement of the respective printing head 5/the printing head mount 8 thereof. For this purpose, as shown in FIG. 6, the tapered spindle is moved in a vertical direction due to a rotation thereof. This vertical movement is translated into a horizontal movement of the printing head/printing head mount via a respective cone.
[0044] FIG. 7 illustrates details of a preferred exemplary embodiment of an inkjet printing machine 1 for printing on a printing substrate 2 such as a web of paper. The inkjet printing machine 1 preferably includes multiple printing units 3 for printing operations involving multiple colors. Every one of the printing units 3 includes a printing bar 4 (only one of which is shown by way of example) oriented in a transverse direction 52a relative to the direction of transport 51 of the printing substrate and including printing heads 5. The drive motor 11 causes a horizontal displacement of at least one of the cleaning devices 10 (preferably a joint displacement of all cleaning devices; e.g. by using a common frame) in a direction of movement 53 along the printing bars 4. In this process, the actuator 22 successively reaches positions opposite every step-by-step switching mechanism 21 and may actuate each one as needed, i.e. shift it once or multiple times as a function of the correction requirements. The corrective movement of the respective printing head 5, the position and/or orientation of which requires correction, is achieved incrementally/in a step-by-step way (and preferably in micrometer steps) in the transverse direction 52a and/or in terms of its angle 52b relative to the direction of transport 51.
[0045] The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention.
LIST OF REFERENCE SYMBOLS
[0046] 1 inkjet printing machine [0047] 2 printing substrate [0048] 3 printing unit [0049] 4 printing bar [0050] 4a crossbar [0051] 5 printing head/printing heads [0052] 5a nozzle surface [0053] 6 line(s) [0054] 7 row [0055] 8 printing head mount [0056] 9 guide [0057] 10 cleaning device [0058] 11 drive motor [0059] 12 computer [0060] 20 adjustment device [0061] 21 step-by-step switching mechanism(s) [0062] 21a first step-by-step switching mechanism [0063] 21b second step-by-step switching mechanism [0064] 22 actuator(s) [0065] 30 locking disk [0066] 31 shifting tongue(s) [0067] 31a first shifting tongue [0068] 31b second shifting tongue [0069] 31c third shifting tongue [0070] 31d fourth shifting tongue [0071] 32 protrusion [0072] 33 first elongated hole [0073] 34 second elongated hole [0074] 35 lateral recess [0075] 36 pin(s) [0076] 37 spring element [0077] 38 block or brake, in particular pressure element [0078] 40a transmission [0079] 40b transmission [0080] 41 gearwheel(s) [0081] 42 tapered spindle(s) [0082] 51 direction of transport of the printing substrate [0083] 52a transverse direction [0084] 52b angle [0085] 53 direction of movement of the cleaning device [0086] 54a first direction of rotation of the locking disk [0087] 54b second direction of rotation of the locking disk [0088] 55 direction of movement of the actuator [0089] 56 direction of movement of the shifting tongue [0090] 57 lateral compensation movement [0091] 58 forward movement/shifting movement [0092] 59 return movement
