Patent ID: 12202284

DETAILED DESCRIPTION

FIG.1, by way of example, schematically shows a perspective illustration in a drastically simplified manner of an array of several, for example four, preferably identical print heads01that each print in an ink jet printing process and collectively print at least part of the surface of a conical body of revolution02. This array of print heads01is located in a printing machine which is not described in greater detail here, the composition and operating principle of which are known to those skilled in the art. During the printing process, the body of revolution02to be printed rotates about the axis of rotation03thereof, wherein a longitudinal axis X2of the body of revolution02to be printed forms this axis of rotation03. Each of these print heads01is arranged, with respect to the surface of the body of revolution02to be printed, in such a way that both the print head is arranged, at least during the printing process, perpendicularly to the surface of this body of revolution02to be printed and that a longitudinal cutting plane04extending through the relevant print head01in each case intersects the axis of rotation03of the body of revolution02to be printed. The respective longitudinal cutting plane04of the relevant print head01also forms the printing plane04thereof.

FIG.1shows several, for example two different, printing planes04, wherein in each case two print heads01of the illustrated array, which are arranged in the same printing plane04, are not seamlessly placed next to one another, but are arranged in a row, spaced apart from one another by a mounting gap06in the relevant printing plane04. Each of the two printing planes04intersects the longitudinal axis X2of the body of revolution02to be printed, and the two rows of print heads01in this array thus create a V formation.

The print heads01arranged in the two printing planes04are preferably arranged in rows that are offset from one another. On the side facing the surfaces of the body of revolution02to be printed, each of these print heads01comprises at least one row, preferably several parallel rows, of printing nozzles07arranged next to one another, wherein each of these printing nozzles07is designed to eject ink, and wherein a length of the relevant row of printing nozzles07defines a printing width08of the relevant print head01. The printing width08of the relevant print head01is smaller than a length L02of the body of revolution02to be printed, so that in each case only a section on the surface of the body of revolution02to be printed can be printed with the printing width08of each print head01. The printing width08of the relevant print head01is, for example, in a range between 50 mm and 100 mm, preferably 70 mm, while the length L02of the body of revolution02to be printed, and generally also of the print image to be printed onto the outer surface thereof, is, for example, in a range between 200 mm and 300 mm. The respective rows of printing nozzles07arranged next to one another, of print heads01arranged in the different printing planes04in offset rows, are arranged so as to complement one another to form one continuous printing line, wherein this printing line is an outer surface line on the surface of the body of revolution02to be printed which is located in the respective longitudinal cutting plane04extending through the relevant print heads01. The at least one print head01is, or all print heads01of this array are, arranged at a distance between 1 mm and less than 8 mm with respect to the surface of the relevant body of revolution02which is to be printed.

It is provided that a three-dimensional, orthogonal coordinate system, the origin of which is arranged in a center of mass09of the relevant print head01and which is fixed in terms of the print head, has a longitudinal axis X1and a transverse axis Y1and a vertical axis Z1, wherein the longitudinal axis X1of the relevant print head01extends parallel to the printing width08of this print head01. A mount12holding the relevant print head01is preferably designed in such a way that the relevant print head01carries out a rotational movement, at least about the vertical axis Z1thereof. Moreover, this mount12of the relevant print head01is preferably designed so as to be movable in such a way that the relevant print head01not only carries out a rotational movement about the vertical axis Z1thereof, but also about the transverse axis Y1thereof and/or about the longitudinal axis X1thereof. Due to the rotatability of the relevant print head01about the vertical axis Z1thereof, and controlled tracking of the printing position of the relevant print head01, it is ensured that the at least one print head01, during the printing process, is always arranged perpendicularly to the surface of the relevant conically shaped article02to be printed, even if this article02has radial run-out in the order of magnitude of, for example, ±2 mm and/or the tolerances of the geometry thereof have a wide range. Due to the identified solution, the relevant print head01, as a result of the three-dimensional positionability thereof, can always be positioned in space with respect to the surface of the relevant article02in such a way that a longitudinal cutting plane04extending through the relevant print head01intersects an axis of rotation03of the relevant article02, wherein the axis of rotation03of the relevant article02is also the longitudinal axis X2thereof.

According to the present invention, several print heads01that each print the surface of the relevant article02in an ink jet printing process are provided, wherein these print heads01are arranged in a row longitudinally in relation to the axis of rotation X2of the article02to be printed, wherein a respective direction of the ink ejected by the respective printing nozzles07of these print heads01and the longitudinal axis X2of the article02to be printed are situated in the same printing plane04, and the respective direction of the ink ejected by the respective printing nozzles07of these print heads01is in each case oriented perpendicularly to the surface of the relevant article02to be printed. Several different printing planes04are provided with respect to the surface of the relevant article02to be printed, wherein each of the printing nozzles07arranged in the different printing planes04ejects the same ink or inks that differ in color from one another, directly adjacent printing planes04creating a V formation.

In addition to the rotationally movable mount12for the relevant print head01, it is furthermore preferably provided that the article02to be printed is held by a holding device that belongs to the printing machine and differs from the mount12that holds the relevant print head01. This holding device is designed, for example, as a clamping device, which holds the article02to be printed by a force acting in opposite directions at the two end faces. As an alternative, this holding device can, for example, be designed as a mandrel holding the article02to be printed by vacuum pressure or as a clamping mandrel. In addition, a three-dimensional, orthogonal coordinate system, the origin of which is arranged in a center of mass11of the relevant article02and which is fixed in terms of the article, has the longitudinal axis X2of the relevant article02and a transverse axis Y2and a vertical axis Z2, wherein the longitudinal axis X2of the relevant article02in general extends parallel to the axis of rotation03of this article02. It is advantageously provided that the holding device of the relevant article02is movably designed in such a way that the relevant article02carries out a respective rotational movement about the transverse axis Y2thereof and/or about the vertical axis Z2thereof.

FIG.2, in a perspective illustration, schematically in a drastically simplified manner shows a first exemplary embodiment for the mount holding the relevant print head01, the mount, for example, being designed such that the relevant print head01carries out at least a rotational movement about the vertical axis Z1thereof. In this first exemplary embodiment, a panel12that is rigidly connected to the relevant print head01is arranged in the printing plane04of the relevant print head01, wherein, if several print heads01are arranged in the same printing plane04, these print heads01, which are preferably arranged in a row, are rigidly connected to the same rigid panel12. If print heads01that are arranged in several different printing planes04are provided, a respective rigid panel12is arranged in each of these printing planes04, wherein the relevant print heads01of a certain printing plane04are rigidly connected to the rigid panel12arranged in this printing plane04. Three, for example identical, preferably electrically actuated or at least actuatable positioning drives13are provided, which at three different contact points A; B; C, engage on the respective rigid panel12, for example in each case via a ball joint14or a coupler16, and during the respective actuation thereof change the position of the relevant rigid panel12and thus the position of the relevant at least one print head01in space. The relevant coupler16comprises, for example, a ball17or a cylinder18at the respective connecting point thereof with the relevant rigid panel12and/or with the relevant positioning drive13. Each of the positioning drives13is designed as a linear motor, for example, wherein each of these positioning drives13is designed to implement an, in particular bidirectional, adjustment path. The three positioning drives13of this first embodiment are controlled by a control unit that, for example, controls the printing process. This control unit is designed so as to track, or at least be able to track, the respective printing position of the relevant print head01during an ongoing printing process, in keeping with the geometrical requirements of the article02to be printed, that is, based on the surface geometry thereof.

FIG.3, in a perspective illustration, schematically in a drastically simplified manner shows a second exemplary embodiment for the mount holding the relevant print head01, the mount, for example, being designed such that the relevant print head01carries out at least a rotational movement about the vertical axis Z1thereof. In this second exemplary embodiment, this mount comprises a first positioning drive21, by way of which the at least one print head01can be displaced, preferably bidirectionally, along the transverse axis Y1thereof. This mount also comprises a second positioning drive22, by way of which the at least one print head01can be, preferably bidirectionally, rotated about the vertical axis Z1thereof. In addition, this mount comprises a third positioning drive23, by way of which the at least one print head01can be rotated, preferably bidirectionally, about the longitudinal axis X1thereof. If several print heads01arranged in the same printing plane04are present, these print heads01, which are preferably arranged in a row, can each be collectively displaced by the relevant positioning drives21;22;23along the respective transverse axis Y1and/or rotated about the respective longitudinal axis X1and/or the respective vertical axis Z1. These positioning drives21;22;23changing the position of the relevant print head01in space are preferably electrically actuated, or at least actuatable, and controlled by a control unit controlling, for example, the printing process. The control unit in this second exemplary embodiment is also designed so as to track, or at least be able to track, the respective printing position of the relevant print head01during an ongoing printing process, in keeping with the geometrical requirements of the article02to be printed, that is, based on the surface geometry thereof.

Although the disclosure herein has been described in language specific to examples of structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described in the examples. Rather, the specific features and acts are disclosed merely as example forms of implementing the claims.