Claims
- 1. An apparatus for coating a tablet with a powder comprising:
a magnetic brush having a rotational magnetic core and a stationary outer shell; a magnetic powder supply for supplying a magnetic developer powder to the magnetic brush; a print head on the outer shell, the print head defining an array of microchannels for forming a plurality of parallel lines of developer in the microchannels, and including means for selectively transferring developer from the lines to a receiver; a receiver electrode arranged in spaced relation to the array of microchannels to define transfer region through which a receiver tablet moves, and control circuitry for operating the print head to transfer powder to the tablet, and a fuser for fixing the transferred powder to the tablet.
- 2. The apparatus of claim 1 wherein the microchannels are longer than they are wide.
- 3. The apparatus of claim 1 wherein the microchannels are deeper than they are wide.
- 4. The apparatus of claim 1 wherein the microchannels have a shaped surface corresponding to the shape of the surface of the tablet that receives the transferred powder.
- 5. The apparatus of claim 1 further comprising an array of a plurality of magnetic brushes as set forth in claim 1 and disposed on a common axis.
- 6. The apparatus of claim 5 further comprising two or more arrays of magnetic brushes, each array on a separate, common axis, for transferring power to a tablet.
- 7. The apparatus of claim 6 wherein the powder transferred by the two or more brushes is the same or different from each other.
- 8. The apparatus of claim 1 further comprising a charged electrode for holding the tablet during transfer of powder to the surface of the tablet.
- 9. The apparatus of claim 8 wherein the charged electrode comprises a surface with vacuum port for applying a vacuum to a surface of the tablet opposite the microchannels.
- 10. The apparatus of claim 1 wherein the printhead comprises a substrate having a plurality of elongated, parallel walls separated from each other to define microchannels and each microchannel having one or more transfer electrodes.
- 11. The apparatus of claim 1 wherein the walls converge at one end of the printhead to provide threshold openings for receiving powder that are wider than the microchannel.
- 12. The apparatus of claim 1 wherein the fuser is a heat lamp.
- 13. The apparatus of claim 1 further comprising a cassette having a plurality of pockets for receiving an holding a tablet, said pocket having one or more vacuum connections for applying a vacuum to the cassette to hold the tablets in place.
- 14. The apparatus of claim 13 further comprising at least two cassettes registerable with each other for transferring tablets from one cassette to the other cassette and at least two transfer stations, each associated with one of the cassettes, for transferring powder to opposite exposed surfaces of tablets in the cassettes.
- 15. An electrostatic powder deposition apparatus for depositing pharmaceutical powder on a specific region of a substrate, comprising:
a) a magnetic brush having a rotating magnetic core and a stationary outer shell; b) a developer supply for supplying a magnetic developer powder to the magnetic brush; c) one or more print heads on the outer shell, each print head including:
an array of microchannels in a substrate for forming a plurality of parallel lines of developer in the channels, a corresponding plurality of transfer electrodes located in the microchannels for selectively transferring developer from the lines to a substrate, driver circuitry located on the opposite side of the substrate from the microchannels for generating and applying transfer signals to the transfer electrodes, a power supply connection for applying power to the driver circuitry, a print head input connection for applying print signals to the print head, the print signal input including a number of electrical conductors fewer than the number of transfer electrodes, logic and control means located on the opposite side of the substrate from the microchannels for applying the print signals to the drive circuitry, and electrical connections between the driver circuitry and the transfer electrodes being formed by via plugs from the bottoms of the microchannels to the opposite side of the substrate; and d) a receiver electrode arranged in spaced relation to the array of microchannels to define a powder transfer region through which the receiver substrate can be moved.
- 16. A method of coating a tablet comprising the steps of:
rotating a magnetic brush through a source of magnetic powder to pick up the powder on the surface of the brush; moving the transferred powder over the surface of the brush toward a transfer station; dividing the powder into microchannels at the transfer station; bringing a tablet proximate the microchannels; applying a potential difference between the tablets and the microchannels for transferring powder to the tablet; and fixing the powder to the tablet.
- 17. The method of claim 16 wherein a plurality of tablets are simultaneously coated.
- 18. The method of claim 17 wherein the plurality of tablets are coated by a corresponding plurality of printheads.
- 19. The method of claim 16 wherein the tablets are coated with a plurality of coatings.
- 20. The method of claim 16 wherein the tablets are coated on all outside surfaces.
- 21. A tablet coated with a powder deposited from microchannels, said tablet having a plurality of alternating regions of powder density corresponding to the pitch of the microchannels that deposited the powder on the tablet.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of the priority date of Provisional Patent Application Serial No. 60/301,070 filed Jun. 26, 2001.
Provisional Applications (1)
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Number |
Date |
Country |
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60301070 |
Jun 2001 |
US |