Nozzle placement in monolithic drop-on-demand print heads

Claim 2

A drop on demand printing head comprising: substrate having front and back surfaces; a plurality of nozzles formed as holes communicating between the back surface of said substrate and the front surface of said substrate, said nozzles being formed in one or more row regions which are generally perpendicular to a print direction, each of said regions being divided into a plurality of multi-nozzle groups at least some of said groups within the regions being displaced in the print direction from other of said groups in the same row region; a body of ink associated with said nozzles; a pressurizing device adapted to subject ink in said body of ink to a pressure of at least 2% above ambient pressure, at least during drop selection and separation to form a meniscus with an air/ink interface; drop selection apparatus operable upon the air/ink interface to select predetermined nozzles and to generate a difference in meniscus position between ink in selected and non-selected nozzles; and drop separation apparatus adapted to cause ink from selected nozzles to separate as drops from the body of ink, while allowing ink to be retained in non-selected nozzles.

Claim 3

A drop on demand printing head as claimed in claim 1 wherein said substrate is composed of single crystal silicon.

Claim 4

A drop on demand printing head as claimed in claim 1 wherein said substrate is a single crystal silicon wafer of (100) crystallographic orientation.

Claim 5

A drop on demand printing head as claimed in claim 1 wherein said substrate is a single crystal silicon wafer of (110) crystallographic orientation.

Claim 6

A drop on demand printing head as claimed in claim 1 wherein the segment groups in each row region alternate in displacement.

Claim 7

A drop on demand printing head as claimed in claim 1 wherein the distance that said segments are displaced from the other segments in each row region is greater than or equal to the width of the ink channel formed in said substrate wherein said width is measured at the back surface of said substrate, and said width is measured in the print direction.

Claim 8

A drop on demand printing head comprising: a substrate having front and back surfaces; a plurality of nozzles formed as holes communicating between the back surface of said substrate and the front surface of said substrate, said nozzles being formed in one or more row regions which are generally perpendicular to a print direction, each of said regions being divided into a plurality of multi-nozzle groups at least some of said groups within the regions being displaced in the print direction from other of said groups in the same row region; a body of ink associated with said nozzles said body of ink forming a meniscus with an air/ink interface at each nozzle; drop selection apparatus operable upon the air/ink interface to select predetermined nozzles and to generate a difference in meniscus position between ink in selected and non-selected nozzles; and drop separation apparatus adapted to cause ink from selected nozzles to separate as drops from the body of ink, while allowing ink to be retained in non-selected nozzles, said drop selection apparatus being capable of producing said difference in meniscus position in the absence of said drop separation apparatus.

Claim 9

A drop on demand printing head comprising: a substrate having front and back surfaces; a plurality of nozzles formed as holes communicating between the back surface of said substrate and the front surface of said substrate, said nozzles being formed in one or more row regions which are generally perpendicular to a print direction, each of said regions being divided into a plurality of multi-nozzle groups at least some of said groups within the regions being displaced in the print direction from other of said groups in the same row region; a body of ink associated with said nozzles said body of ink forming a meniscus with an air/ink interface at each nozzle; drop selection apparatus operable upon the air/ink interface to select predetermined nozzles and to generate a difference in meniscus position between ink in selected and non-selected nozzles; and drop separation apparatus adapted to cause ink from selected nozzles to separate as drops from the body of ink, while allowing ink to be retained in non-selected nozzles, said drop selection apparatus being capable of producing said difference in meniscus position in the absence of said drop separation apparatus.

Claim 10

A drop on demand printing head as claimed in claim 7 wherein said substrate is composed of single crystal silicon.

Claim 11

A drop on demand printing head as claimed in claim 7 wherein said substrate is a single crystal silicon wafer of (100) crystallographic orientation.

Claim 12

A drop on demand printing head as claimed in claim 7 wherein said substrate is a single crystal silicon wafer of (110) crystallographic orientation.

Claim 13

A drop on demand printing head as claimed in claim 7 wherein the segment groups in each row region alternate in displacement.

Claim 14

A drop on demand printing head as claimed in claim 7 wherein the distance that said segments are displaced from the other segments in each row region is greater than or equal to the width of the ink channel formed in said substrate wherein said width is measured at the back surface of said substrate, and said width is measured in the print direction.

Claim 15

A drop on demand printing head comprising: a substrate having front and back surfaces; a plurality of nozzles formed as holes communicating between the back surface of said substrate and the front surface of said substrate, said nozzles being formed in one or more row regions which are generally perpendicular to a print direction, each of said regions being divided into a plurality of multi-nozzle groups at least some of said groups within the regions being displaced in the print direction from other of said groups in the same row region; a body of ink associated with said nozzles, said body of ink forming a meniscus with an air/ink interface at each nozzle and said ink exhibiting a surface tension decrease of at least 10 mN/m over a 30° C. temperature range; drop selection apparatus operable upon the air/ink interface to select predetermined nozzles and to generate a difference in meniscus position between ink in selected and non-selected nozzles; and drop separation apparatus adapted to cause ink from selected nozzles to separate as drops from the body of ink, while allowing ink to be retained in non-selected nozzles.

Claim 16

A drop on demand printing head comprising: a substrate having front and back surfaces; a plurality of nozzles formed as holes communicating between the back surface of said substrate and the front surface of said substrate, said nozzles being formed in one or more row regions which are generally perpendicular to a print direction, each of said regions being divided into a plurality of multi-nozzle groups at least some of said groups within the regions being displaced in the print direction from other of said groups in the same row region; a body of ink associated with said nozzles, said body of ink forming a meniscus with an air/ink interface at each nozzle and said ink exhibiting a surface tension decrease of at least 10 mN/m over a 30° C. temperature range; drop selection apparatus operable upon the air/ink interface to select predetermined nozzles and to generate a difference in meniscus position between ink in selected and non-selected nozzles; and drop separation apparatus adapted to cause ink from selected nozzles to separate as drops from the body of ink, while allowing ink to be retained in non-selected nozzles.

Claim 17

A drop on demand printing head as claimed in claim 13 wherein said substrate is composed of single crystal silicon.

Claim 18

A drop on demand printing head as claimed in claim 13 wherein said substrate is a single crystal silicon wafer of (100) crystallographic orientation.

Claim 19

A drop on demand printing head as claimed in claim 13 wherein said substrate is a single crystal silicon wafer of (110) crystallographic orientation.

Claim 20

A drop on demand printing head as claimed in claim 13 wherein the segment groups in each row region alternate in displacement.

Claim 21

A drop on demand printing head as claimed in claim 13 wherein the distance that said segments are displaced from the other segments in each row region is greater than or equal to the width of the ink channel formed in said substrate wherein said width is measured at the back surface of said substrate, and said width is measured in the print direction.