Electrostatic printhead

Claim 2

An electrostatic printhead comprising: a plurality of styli for printing, each stylus being an end portion of a conductive trace formed on a substrate and being spaced apart by an air gap from a return path for a current carried by the conductive trace; a plurality of driver circuits and associated logic circuitry grouped into at least one integrated circuit die mounted to the substrate, each driver circuit electrically controlling one stylus; and electrical interconnections for connecting each driver circuit to one conductive trace.

Claim 3

The printhead of claim 1, wherein the integrated circuit die is mounted to the substrate by the electrical interconnections extending from terminals of the die to the traces.

Claim 4

The printhead of claim 2, wherein each conductive trace is connected to an associated terminal of the integrated circuit die by a tape automated bond.

Claim 5

The printhead of claim 1, wherein all of the styli and all of the integrated circuit die are on one side of the substrate.

Claim 6

The printhead of claim 1, further comprising a plurality of integrated circuit die and wherein the substrate has first and second opposing surfaces and wherein the styli are formed in two rows, one row being formed on each of the opposing surfaces, and at least one integrated circuit die is mounted to the first surface and at least one integrated circuit die is mounted to the second surface.

Claim 7

The printhead of claim 1 further comprising: a second substrate; and means for spacing apart the two substrates and to which a surface of the first and a surface of the second substrate are fastened; wherein a first portion of the plurality of styli is formed on the first substrate; at least one integrated circuit die including a plurality of the driver circuits for driving the styli in the first portion of the styli is on a surface of the first substrate; a second portion of the plurality of styli is formed on the second substrate; and at least one integrated circuit die for driving the styli in the second portion of the styli is on a surface of the second substrate.

Claim 8

The printhead of claim 6, wherein the surfaces of the first and second substrates on which the styli are formed are the surfaces fastened to the spacer means.

Claim 9

The printhead of claim 1, wherein the substrate comprises ceramic material.

Claim 10

The printhead of claim 1, wherein the substrate comprises glass-epoxy printed circuit board material.

Claim 11

The printhead of claim 1, wherein each trace is connected to a terminal of the integrated circuit die with a wire bond.

Claim 12

The printhead of claim 1, wherein each conductive trace is connected to an associated terminal of the integrated circuit die by a tape automated bond.

Claim 13

The printhead of claim 1, wherein each conductive trace is one inch or less in length.

Claim 14

The printhead of claim 1, wherein each conductive trace is two inches or less in length.

Claim 15

The printhead of claim 1, wherein the styli are of substantially uniform width and there is a space between adjacent styli, and the space has a width at least equal to the width of one trace.

Claim 16

The printhead of claim 1, wherein each driver is limited to about 1 milliamp current or less.

Claim 17

The printhead of claim 1, wherein each driver circuit comprises means for programming the current level provided by the driver by current limiting.

Claim 18

The printhead of claim 1, wherein the integrated circuit die includes a serial to parallel data converter for providing a driving signal to each of the plurality of drive circuits from serial input data.

Claim 19

An electrostatic printhead comprising: a plurality of styli for printing, each stylus being an end portion of a conductive trace formed on a first substrate; a plurality of drivers grouped into at least one integrated circuit die mounted to the first substrate, each driver electrically controlling one stylus; electrical interconnections for connecting each driver to one conductive trace; a second substrate; means for spacing apart the two substrates and to which a surface of the first and a surface of the second substrate are fastened; wherein a first portion of the plurality of styli is formed on the first substrate; at least one integrated circuit die for driving the styli in the first portion of the styli is on a surface of the first substrate; a second portion of the plurality of styli is formed on the second substrate; at least one integrated circuit die for driving the styli in the second portion of styli is on a surface of the second substrate; wherein the surfaces of the first and second substrates on which the styli are formed are the surfaces fastened to the means for spacing; and wherein at least one integrated circuit die is on a recessed portion of the surface of the first substrate.

Claim 20

An electrostatic printhead comprising: a plurality of styli for printing, each stylus being an end portion of a conductive trace formed on a first substrate; a plurality of drivers grouped into at least one integrated circuit die mounted to the first substrate, each driver electrically controlling one stylus; electrical interconnections for connecting each driver to one conductive trace; a second substrate; means for spacing apart the two substrates and to which a surface of the first and a surface of the second substrate are fastened; wherein a first portion of the plurality of styli is formed on the first substrate; at least one integrated circuit die for driving the styli in the first portion of the styli is on a surface of the first substrate; a second portion of the plurality of styli is formed on the second substrate; at least one integrated circuit die for driving the styli in the second portion of styli is on a surface of the second substrate; wherein the surfaces of the first and second substrates on which the styli are formed are the surfaces fastened to the means for spacing; and wherein at least one integrated circuit die is on a recessed portion of the surface of the first substrate.

Claim 21

The printhead of claim 1, further comprising means for supporting fastened to the first substrate.

Claim 22

The printhead of claim 1, further comprising: a second substrate having a surface on which a plurality of styli are formed; a plurality of driver circuits grouped into an integrated circuit die mounted to the second substrate for electrically controlling the plurality of styli on the second substrate, said second substrate; and means for supporting fastened to the first substrate.

Claim 23

An electrostatic printhead comprising: a plurality of styli for printing, each stylus being an end portion of a conductive trace formed on a substrate; a plurality of drivers grouped into at least one integrated circuit die mounted to the substrate, each diver electrically controlling one stylus; and electrical interconnections for connecting each driver to one conductive trace; a second substrate having a surface on which a plurality of styli are formed; a plurality of drivers groups into an integrated circuit die mounted to the second substrate for electrically controlling the plurality of styli on the second substrate, said second substrate being fastened in fixed relation to the first substrate; means for supporting fastened to the first substrate for supporting the substrate; and a third substrate having a surface on which a plurality of styli are formed, at least one integrated circuit die including drivers being mounted to the third substrate for driving each styli on the third substrate, the third substrate being in fixed relation to the second substrate.

Claim 24

An electrostatic printhead comprising: a plurality of styli for printing, each stylus being an end portion of a conductive trace formed on a substrate; a plurality of drivers grouped into at least one integrated circuit die mounted to the substrate, each diver electrically controlling one stylus; and electrical interconnections for connecting each driver to one conductive trace; a second substrate having a surface on which a plurality of styli are formed; a plurality of drivers groups into an integrated circuit die mounted to the second substrate for electrically controlling the plurality of styli on the second substrate, said second substrate being fastened in fixed relation to the first substrate; means for supporting fastened to the first substrate for supporting the substrate; and a third substrate having a surface on which a plurality of styli are formed, at least one integrated circuit die including drivers being mounted to the third substrate for driving each styli on the third substrate, the third substrate being in fixed relation to the second substrate.

Claim 25

An electrostatic printhead comprising: a plurality of styli for printing, each stylus being an end portion of a conductive trace formed on a substrate; a plurality of drivers grouped into at least one integrated circuit die mounted to the substrate, each driver electrically controlling one stylus; electrical interconnections for connecting each driver to one conductive trace; and a second substrate having a surface on which styli are formed, the second substrate being fastened in fixed relation to the first substrate, wherein the drivers of the integrated circuit die mounted to the first substrate driver the styli on the second substrate.

Claim 26

An electrostatic printhead comprising: a plurality of styli for printing, each stylus being an end portion of a conductive trace formed on a substrate; a plurality of drivers grouped into at least one integrated circuit die mounted to the substrate, each driver electrically controlling one stylus; electrical interconnections for connecting each driver to one conductive trace; and a second substrate having a surface on which styli are formed, the second substrate being fastened in fixed relation to the first substrate, wherein the drivers of the integrated circuit die mounted to the first substrate driver the styli on the second substrate.

Claim 27

An electrostatic printhead comprising: a plurality of styli for printing, each stylus being an end portion of a conductive trace formed on a substrate; a plurality of drivers grouped into at least one integrated circuit die mounted to the substrate, each driver electrically controlling one stylus; electrical interconnections for connecting each driver to one conductive trace; means for supporting fastened to the first substrate for supporting the substrate; and wherein the means for supporting comprises a metal plate embedded in printed circuit board material.

Claim 28

An electrostatic printhead comprising: a plurality of styli for printing, each stylus being an end portion of a conductive trace formed on a substrate; a plurality of drivers grouped into at least one integrated circuit die mounted to the substrate, each driver electrically controlling one stylus; electrical interconnections for connecting each driver to one conductive trace; means for supporting fastened to the first substrate for supporting the substrate; and wherein the means for supporting comprises a metal plate embedded in printed circuit board material.

Claim 29

An electrostatic printhead comprising: a plurality of styli for printing, each stylus being an end portion of a conductive trace formed on a substrate; a plurality of drivers groups into at least one integrated circuit die mounted to the substrate, each diver electrically controlling one stylus; and electrical interconnections for connecting each driver to one conductive trace; wherein each of the plurality of drivers comprises at least one P-channel transistor and at least one N-channel transistor thereby providing a complementary driving circuit.

Claim 30

An electrostatic printhead comprising: a plurality of styli for printing, each stylus being an end portion of a conductive trace formed on a substrate; a plurality of drivers groups into at least one integrated circuit die mounted to the substrate, each diver electrically controlling one stylus; and electrical interconnections for connecting each driver to one conductive trace; wherein each of the plurality of drivers comprises at least one P-channel transistor and at least one N-channel transistor thereby providing a complementary driving circuit.

Claim 31

A printhead for high voltage electrostatic printing directly onto a permanent medium comprising: at least one stylus formed on a substrate for depositing electric charge directly on the permanent medium; and at least one driver circuit and associated logic circuitry for driving the stylus with an output current of less than about 10 microamps grouped into at least one integrated circuit die and mounted on the substrate within two inches of an end of the stylus at a printing edge of the substrate, wherein the number of styli and the number of driver circuits are substantially in a one-to-one correspondence.

Claim 32

A printhead for high voltage electrostatic printing directly onto a permanent medium comprising: at least one stylus formed on a substrate for depositing electric charge directly on the permanent medium; and at least one driver circuit and associated logic circuitry for driving the stylus with an output current of less than about 10 microamps grouped into at least one integrated circuit die and mounted on the substrate within two inches of an end of the stylus at a printing edge of the substrate, wherein the number of styli and the number of driver circuits are substantially in a one-to-one correspondence.

Claim 33

An electrostatic printhead comprising: a plurality of styli for printing formed on a substrate; and a plurality of driver circuits each electrically connected to one of the styli and grouped into at least one integrated circuit die mounted on the substrate, wherein the integrated circuit die actively drives each stylus to a high voltage and actively drives each stylus to a low voltage at least about 250 volts less than the high voltage.

Claim 34

An electrostatic printhead comprising: a plurality of styli for printing formed on a substrate; and a plurality of driver circuits each electrically connected to one of the styli and grouped into at least one integrated circuit die mounted on the substrate, wherein the integrated circuit die actively drives each stylus to a high voltage and actively drives each stylus to a low voltage at least about 250 volts less than the high voltage.

Claim 35

A printhead for high voltage electrostatic printing directly onto a permanent medium comprising: a rigid substrate; a plurality of styli for electrostatically depositing electric charge directly on the permanent printing medium; a plurality of integrated circuit die, each including a plurality of driver circuits and each integrated circuit die being mounted on the substrate, each driver electrically controlling one associated stylus; electrical interconnections formed on the substrate for connecting each driver to the associated stylus; and a support plate fastened to the substrate.

Claim 36

A printhead for high voltage electrostatic printing directly onto a permanent medium comprising: a rigid substrate; a plurality of styli for electrostatically depositing electric charge directly on the permanent printing medium; a plurality of integrated circuit die, each including a plurality of driver circuits and each integrated circuit die being mounted on the substrate, each driver electrically controlling one associated stylus; electrical interconnections formed on the substrate for connecting each driver to the associated stylus; and a support plate fastened to the substrate.

Claim 37

A printhead for high voltage electrostatic printing directly onto a permanent medium comprising: a rigid substrate; a plurality of styli formed on the substrate for electrostatically depositing electric charge directly on the permanent printing medium, each stylus being substantially wider than it is thick; a plurality of integrated circuit die, each including a plurality of driver circuits and each integrated circuit die being mounted on the substrate, each driver electrically controlling one associated stylus; and electrical interconnections formed on the substrate for connecting each driver circuit to the associated stylus.

Claim 38

A printhead for high voltage electrostatic printing directly onto a permanent medium comprising: a rigid substrate; a plurality of styli formed on the substrate for electrostatically depositing electric charge directly on the permanent printing medium, each stylus being substantially wider than it is thick; a plurality of integrated circuit die, each including a plurality of driver circuits and each integrated circuit die being mounted on the substrate, each driver electrically controlling one associated stylus; and electrical interconnections formed on the substrate for connecting each driver circuit to the associated stylus.