Device and Method for Applying Flowable Material to a Substratum That Can Be Rotated About an Axis of Rotation

An apparatus (1) for applying flowable material onto a substrate (3) that is rotatable about an axis of rotation (4), according to predetermined image data which are stored in a first memory (18) as pixels or vectors of a specific Cartesian coordinate system, having at least one printing head (13A, 13B) which has a plurality of nozzles arranged at a nozzle distance from one another for discharging material droplets of the flowable material and which is arranged at a vertical distance from the substrate, and having an actuation device (8) for positioning the substrate (3) relative to the at least one printing head (13A, 13B) and for controlling the discharge of the material droplets, wherein a second memory (19) is present, in which special polar coordinate grid points (20, 20′, 20A, 20B) of a specific polar coordinate grid are stored, said special polar coordinate grid points being arranged on circles (R1, R2, R1′ . . . R7′, R1″ . . . R13″) which have a predetermined circumferential distance from one another and being arranged on first rays (A1, A1′) which have a first angular distance from one another and being arranged on further rays (A2, A2′, A3′) in the direction of the origin, said further rays having an angular distance from one another that is greater than the first angular distance, said special polar coordinate grid points being stored as Cartesian grid points in coordinates of the specific Cartesian coordinate system, wherein a computer (15) is present, by means of which the Cartesian grid points are compared to the pixels or the vectors of the image data, and wherein the nozzles of the printing head (13A, 13B) are controllable in such a way that they only discharge material droplets when their position relative to the substrate corresponds to the position of a special polar coordinate grid point (20A, 20B) at which the comparison yields a correspondence.

An apparatus (1) for applying flowable material onto a substrate (3) that is rotatable about an axis of rotation (4), according to predetermined image data which are stored in a first memory (18) as pixels or vectors of a specific Cartesian coordinate system, having at least one printing head (13A, 13B) which has a plurality of nozzles arranged at a nozzle distance from one another for discharging material droplets of the flowable material and which is arranged at a vertical distance from the substrate, and having an actuation device (8) for positioning the substrate (3) relative to the at least one printing head (13A, 13B) and for controlling the discharge of the material droplets, wherein a second memory (19) is present, in which special polar coordinate grid points (20, 20′, 20A, 20B) of a specific polar coordinate grid are stored, said special polar coordinate grid points being arranged on circles (R1, R2, R1′ . . . R7′, R1″ . . . R13″) which have a predetermined circumferential distance from one another and being arranged on first rays (A1, A1′) which have a first angular distance from one another and being arranged on further rays (A2, A2′, A3′) in the direction of the origin, said further rays having an angular distance from one another that is greater than the first angular distance, wherein a computer (15) is present, by means of which the pixels or vectors stored in the first memory (18) are transformable into polar coordinates and the polar coordinate image data obtained thus are compared to the special polar coordinate grid points (20, 20′, 20A, 20B) stored in the second memory (19), and wherein the nozzles of the printing head (13A, 13B) are controllable in such a way that they only discharge material droplets when their position relative to the substrate corresponds to the position of a special polar coordinate grid point (20A, 20B) at which the comparison yields a correspondence.

A method for applying flowable material onto a substrate (3) that is rotatable about an axis of rotation (4), according to predetermined image data which are stored in a first memory (18) as pixels or vectors of a specific Cartesian coordinate system, wherein material droplets of the flowable material are applied onto the substrate (3) by means of a printing head (13A, 13B) which has a plurality of nozzles arranged at a nozzle distance from one another, wherein special polar coordinate grid points (20, 20′, 20A, 20B) of a specific polar coordinate grid are determined, said special polar coordinate grid points being arranged on circles (R1, R2, R1′ . . . R7′, R1″ . . . R13″) which have a predetermined circumferential distance from one another and being arranged on first rays (A1, A1′) which have a first angular distance from one another and said special polar coordinate grid points being arranged on further rays (A2, A2′, A3′) in the direction of the origin, said further rays having an angular distance from one another which is greater than the first angular distance, wherein the special polar coordinate grid points (20, 20′, 20A, 20B) are transformed into coordinates of the specific Cartesian coordinate system, and the Cartesian grid points obtained thus are compared to the pixels or the vectors of the image file, and wherein the nozzles of the printing head (13A, 13B) are controlled in such a way that they only discharge material droplets when their position relative to the substrate corresponds to the position of a special polar coordinate grid point (20A, 20B) at which the comparison yields a correspondence.

A method for applying flowable material onto a substrate (3) that is rotatable about an axis of rotation (4), according to predetermined image data which are stored in a first memory (18) as pixels or vectors of a specific Cartesian coordinate system, wherein material droplets of the flowable material are applied onto the substrate (3) by means of a printing head (13A, 13B) which has a plurality of nozzles arranged at a nozzle distance from one another, wherein special polar coordinate grid points (20, 20′, 20A, 20B) of a specific polar coordinate grid are determined, said special polar coordinate grid points being arranged on circles (R1, R2, R1′ . . . R7′, R1″ . . . R13″) which have a predetermined circumferential distance from one another and being arranged on first rays (A1, A1′) which have a first angular distance from one another and said special polar coordinate grid points being arranged on further rays (A2, A2′, A3′) in the direction of the origin, said further rays having an angular distance from one another which is greater than the first angular distance, wherein the pixels or vectors of the specific Cartesian coordinate system are transformed into polar coordinates, and the polar coordinate image data obtained thus are compared to the special polar coordinate grid points (20, 20′, 20A, 20B), and wherein the nozzles of the printing head (13A, 13B) are controlled in such a way that they only discharge material droplets when their position relative to the substrate corresponds to the position of a special polar coordinate grid point (20A, 20B) at which the comparison yields a correspondence.