A device for applying flowable material to a substratum rotated about an axis of rotation, in accordance with image data stored as pixels or vectors of a Cartesian coordinate grid in a first memory, has at least one printing head for discharging material drops of the flowable material, and is arranged above the substratum, and a controller for positioning the substratum in relation to the printing head and controlling the discharge of the material drops. In a second memory, special polar coordinate grid points arranged on circular lines and on first rays having a first angular distance and, in the direction of origin, on further rays having an angular distance from each other that is greater than the first angular distance are stored. The special polar coordinate grid points are transformed into coordinates of the Cartesian coordinate system, and are compared with the pixels of the image file.

A device for applying flowable material to a substratum rotated about an axis of rotation, in accordance with image data stored as pixels or vectors of a Cartesian coordinate grid in a first memory, has at least one printing head for discharging material drops of the flowable material, and is arranged above the substratum, and a controller for positioning the substratum in relation to the printing head and controlling the discharge of the material drops. In a second memory, special polar coordinate grid points arranged on circular lines and on first rays having a first angular distance and, in the direction of origin, on further rays having an angular distance from each other that is greater than the first angular distance are stored. The special polar coordinate grid points are transformed into coordinates of the Cartesian coordinate system, and are compared with the pixels of the image file.

The invention relates to a device for applying flowable material to a substratum (3), which can be rotated about an axis of rotation (4), in accordance with specified image data, which are stored as pixels or as vectors of a certain Cartesian coordinate grid in a first memory (18), has at least one printing head (13A, 13B), which has a plurality of nozzles arranged at a nozzle distance from each other for discharging material drops of the flowable material and is arranged at a vertical distance from the substratum, and a controller (8) for positioning the substratum (3) in relation to the at least one printing head (13A, 13B) and the discharge of the material drops. In a second memory (19), particular polar coordinate grid points (20A, 20B) of a certain polar coordinate grid are stored, which polar coordinate grid points are arranged on circular lines (R1, R2) having a predetermined circular-line distance from each other and are arranged on first rays (A1), which have a first angular distance from each other and are arranged in the direction of origin on further rays (A2) having an angular distance from each other that is greater than the first angular distance. A computer (15) is present, by means of which the particular polar coordinate grid points (20A, 20B) stored in the second memory (19) can be transformed into coordinates of the certain Cartesian coordinate system and the Cartesian grid points thus obtained are compared with the pixels of the image file.

The invention relates to a device for applying flowable material to a substratum (3), which can be rotated about an axis of rotation (4), in accordance with specified image data, which are stored as pixels or as vectors of a certain Cartesian coordinate grid in a first memory (18), has at least one printing head (13A, 13B), which has a plurality of nozzles arranged at a nozzle distance from each other for discharging material drops of the flowable material and is arranged at a vertical distance from the substratum, and a controller (8) for positioning the substratum (3) in relation to the at least one printing head (13A, 13B) and the discharge of the material drops. In a second memory (19), particular polar coordinate grid points (20A, 20B) of a certain polar coordinate grid are stored, which polar coordinate grid points are arranged on circular lines (R1, R2) having a predetermined circular-line distance from each other and are arranged on first rays (A1), which have a first angular distance from each other and are arranged in the direction of origin on further rays (A2) having an angular distance from each other that is greater than the first angular distance. A computer (15) is present, by means of which the particular polar coordinate grid points (20A, 20B) stored in the second memory (19) can be transformed into coordinates of the certain Cartesian coordinate system and the Cartesian grid points thus obtained are compared with the pixels of the image file.