# US 6,400,385 B1 · Microchannel print head for electrographic printer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,400,385 B1 - Document ID: US6400385B1 - Status: Granted - Kind: B1 - Application number: 08/782,272 - Filed: 1997-01-13 - Granted: 2002-06-04 - Earliest claimed: 1996-03-22 - Assignees: Eastman Kodak Company - Inventors: William J. Grande; William Mey; Thomas M. Stephany; Thomas N. Tombs - Web page: https://patentgrep.com/patent/US6400385B1 ## CPC - G03G 15/348: {using a stylus or a multi-styli array} - B41J 2/43: for magnetic printing - G03G 2217/0016: where the toner is conveyed over the electrode array to get a charging and then being moved - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS ## Abstract Electrographic printing apparatus for forming a toner image on a recording medium includes: a magnetic brush having a rotatable magnetic core and a stationary outer cylindrical shell; a developer supply for supplying a magnetic developer powder to the magnetic brush; an array of microchannels on the outer shell for forming a plurality of parallel lines of developer in the channels; means for selectively transferring developer from the lines to a receiver; and a receiver electrode arranged in spaced relation to the array of microchannels to define a recording region through which the receiver can be moved. ## Claims ### Claim 1 Electrographic printing apparatus for forming a toner image on a recording medium, comprising: a) a magnetic brush having a rotatable magnetic core and a stationary outer shell; b) a developer supply for supplying a magnetic developer powder to the magnetic brush; c) 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, the microchannels being at least 10 times longer and at least twice as deep as they are wide and including means for selectively transferring developer from the lines to a receiver; and d) a receiver electrode arranged in spaced relation to the array of microchannels to define a recording region through which the receiver can be moved. ### Claim 2 (depends on 1) The electrographic printing apparatus claimed in claim 1, wherein the print head comprises a nonflexible substrate having microchannel walls formed from photoimageable polymer. ### Claim 3 (depends on 1) The electrographic printing apparatus claimed in claim 1, wherein the developer is a dual-component developer. ### Claim 4 (depends on 1) The electrographic printing apparatus claimed in claim 1, further comprising strips of magnetically permeable material located in the microchannels. ### Claim 5 (depends on 1) The electrographic printing apparatus claimed in claim 1, wherein the print head includes a silicon substrate, and the means for selectively transferring developer are transfer electrodes located in the microchannels. ### Claim 6 (depends on 5) The electrographic printing apparatus claimed in claim 5, wherein the transfer electrodes are gold. ### Claim 7 (depends on 5) The electrographic printing apparatus claimed in claim 5, further comprising a circuit for selectively applying charge to the transfer electrodes, the circuit being integrated into the silicon substrate. ### Claim 8 (depends on 1) The electrographic printing apparatus claimed in claim 1, further comprising a skive for leveling the developer on the outer shell. ### Claim 9 (depends on 1) The electrographic printing apparatus claimed in claim 1, wherein the microchannels are tapered to funnel the developer into the channels. ### Claim 10 (depends on 1) The electrographic printing apparatus claimed in claim 1, wherein the microchannels include an anti-abrasion layer on the sides and tops of the walls defining the channels. ### Claim 11 (depends on 1) The electrographic printing apparatus claimed in claim 1, wherein the channels are narrower at the top than at the bottom to improve resolution. ### Claim 12 (depends on 1) The electrographic printing apparatus claimed in claim 1, wherein the channels are narrower at the bottom than at the top to improve developer flow. ### Claim 13 (depends on 1) The electrographic printing apparatus claimed in claim 1, wherein the microchannels include an antistatic layer on the sides and tops of the walls defining the channels. ### Claim 14 An electrographic printing method, comprising the steps of: a) supplying a magnetic developer to a print head; b) confining the developer at the print head with an array of microchannels to form a plurality of parallel lines of developer in the microchannels, the microchannels being at least 10 times longer and at least twice as deep as they are wide; and c) selectively transferring developer in an imagewise manner from the lines to a receiver. ### Claim 15 (depends on 14) The electrographic printing method claimed in claim 14, wherein the microchannels are formed on a silicon substrate by integrated circuit manufacturing techniques. ### Claim 16 (depends on 14) The electrographic printing method claimed in claim 14, wherein the developer is a dual-component developer. ### Claim 17 (depends on 14) The electrographic printing method claimed in claim 14, further including the step of further confining the developer with an array of magnetically permeable strips. ### Claim 18 (depends on 17) The electrographic printing method claimed in claim 17, wherein the magnetically permeable strips are located in the microchannels. ### Claim 19 (depends on 17) The electrographic printing method claimed in claim 17, wherein the magnetically permeable strips are located at and aligned with entrances to the microchannels. ### Claim 20 (depends on 14) The electrographic printing method claimed in claim 14, wherein the microchannels are formed by stamping. ### Claim 21 (depends on 14) The electrographic printing apparatus claimed in claim 14, further comprising the step of leveling the developer with a skive prior to providing it to the print head. ### Claim 22 A print head for an electrographic printer of the type having a magnetic brush for transporting magnetic developer to a recording region and a receiver for receiving an imagewise pattern of a component of the developer at the recording region, comprising: a) a substrate defining a plurality of parallel microchannels for confining the developer to flow in the microchannels, the microchannels being at least 10 times longer and at least twice as deep as they are wide; and b) a corresponding plurality of selectively addressable transfer electrodes located at the bottom of each microchannel for selectively transferring the component of the developer to the receiver from the microchannel. ### Claim 23 (depends on 22) The print head claimed in claim 22, wherein the substrate is silicon. ### Claim 24 (depends on 22) The print head claimed in claim 22, further comprising strips of magnetically permeable material located in the microchannels. ### Claim 25 (depends on 22) The print head claimed in claim 22, further comprising strips of magnetically permeable material aligned with the entrances to the microchannels. ### Claim 26 (depends on 23) The print head claimed in claim 23, wherein the transfer electrodes are integrated into the silicon substrate. ### Claim 27 (depends on 23) The print head claimed in claim 23, further comprising circuitry for selectively applying charge to the transfer electrodes, the circuitry being integrated into the silicon substrate. ### Claim 28 (depends on 22) The print head claimed in claim 22, wherein the end of the microchannels are tapered to funnel developer into the microchannels. ### Claim 29 (depends on 22) The print head claimed in claim 22, further comprising an antiabrasion layer on a surface of the print head. ### Claim 30 (depends on 22) The print head claimed in claim 22, wherein the microchannels are narrower at the top than at the bottom to improve resolution. ### Claim 31 (depends on 22) The print head claimed in claim 22, wherein the microchannels are narrower at the bottom than at the top to improve developer flow in the channels. ### Claim 32 (depends on 1) The electrographic printing apparatus claimed in claim 1, wherein the print head comprises a flexible substrate having microchannel walls formed from photoimageable polymer. ### Claim 33 Electrographic printing apparatus for forming a toner image on a recording medium, comprising: a) a magnetic brush having a magnetic core and an outer shell; b) a developer supply for supplying a magnetic developer powder to the magnetic brush; c) a print head adjacent the outer shell, the print head defining an array of microchannels for forming a plurality of parallel lines of developer in the microchannels, the microchannels being at least 10 times longer and at least twice as deep as they are wide, and including means for selectively transferring developer from the lines to a receiver; and d) a receiver electrode arranged in spaced relation to the array of microchannels to define a recording region through which the receiver can be moved. ### Claim 34 (depends on 5) The electrographic printing apparatus claimed in claim 5, wherein the transfer electrodes are staggered. ### Claim 35 (depends on 22) The print head claimed in claim 22, wherein the transfer electrodes are staggered. ### Claim 36 (depends on 33) The electrographic printing apparatus claimed in claim 33, wherein the means for selectively transferring developer are transfer electrodes located in the microchannels. ### Claim 37 (depends on 36) The electrographic printing apparatus claimed in claim 36, wherein the transfer electrodes are staggered.