One-step encapsulation, air gap sealing and structure bonding of thermal ink jet printhead

Claim 3

The method of claim 1, further comprising the step of stopping flow of encapsulant in a forward direction toward the front face of the printhead when said encapsulant flows substantially to the front face of said printhead.

Claim 4

The method of claim 1, further comprising the step of constraining said encapsulant in a rearward direction by a dam bar located on a bottom surface of said manifold and transverse to said manifold legs.

Claim 5

The method of claim 3, wherein said constraining step allows limited flow of encapsulant past said dam bar to enhance structural bonding.

Claim 6

The method of claim 2, wherein said step of stopping flow of encapsulant includes sensing a position of the flow by an optical sensor.

Claim 7

The method of claim 2, wherein said step of stopping flow of encapsulant includes sensing a position of the flow by visual inspection by an operator.

Claim 8

The method of claim 6, further including a step of coloring said substrate to a color different from said encapsulant to aid in detection of encapsulant flow.

Claim 9

The method of claim 7, wherein said step of coloring the substrate to a different color includes providing said substrate with a screen printed silver filler die bonding epoxy to provide a white background for the encapsulant.

Claim 10

A thermal ink jet printhead comprising: a heat sinking substrate having a through hole formed therein; a printhead die mounted on the substrate on one side of the through hole and comprising a channel section with an ink inlet and a heater section with a row of wire bond pads; an interconnection board bonded to the substrate on an opposite side of the through hole and having a corresponding row of wire bond pads; a plurality of wire bonds electrically interconnecting the row of wire bond pads on the heater section and the interconnection board; a manifold mounted to the substrate and defining therein a cavity for reception of the printhead die, interconnection board and plurality of wire bonds, the manifold including an ink inlet for communication with the ink inlet of the channel section; constraining means adjacent the interconnection board for constraining the flow of encapsulant; and the through hole communicating with the cavity and the cavity containing an encapsulant injected through the through hole for encapsulating the wire bonds, sealing air gaps between the manifold and the printhead die, and bonding the manifold to the substrate, wherein the channel section, heater section, through hole and interconnection board define a longitudinal direction of the substrate, the one side of the through hole defining a forward direction and the other side of the through hole defining a rearward direction, the cavity having a width in a transverse direction perpendicular to the longitudinal direction, and said constraining means constrains the flow of encapsulant in the rearward direction.

Claim 11

A thermal ink jet printhead comprising: a heat sinking substrate having a through hole formed therein; a printhead die mounted on the substrate on one side of the through hole and comprising a channel section with an ink inlet and a heater section with a row of wire bond pads; an interconnection board bonded to the substrate on an opposite side of the through hole and having a corresponding row of wire bond pads; a plurality of wire bonds electrically interconnecting the row of wire bond pads on the heater section and the interconnection board; a manifold mounted to the substrate and defining therein a cavity for reception of the printhead die, interconnection board and plurality of wire bonds, the manifold including an ink inlet for communication with the ink inlet of the channel section; constraining means adjacent the interconnection board for constraining the flow of encapsulant; and the through hole communicating with the cavity and the cavity containing an encapsulant injected through the through hole for encapsulating the wire bonds, sealing air gaps between the manifold and the printhead die, and bonding the manifold to the substrate, wherein the channel section, heater section, through hole and interconnection board define a longitudinal direction of the substrate, the one side of the through hole defining a forward direction and the other side of the through hole defining a rearward direction, the cavity having a width in a transverse direction perpendicular to the longitudinal direction, and said constraining means constrains the flow of encapsulant in the rearward direction.

Claim 12

The printhead of claim 9, wherein the constraining means is a dam bar mounted on an undersurface of the manifold and extending substantially across the cavity in the transverse direction.

Claim 13

The printhead of claim 9, wherein the manifold has legs extending in the longitudinal direction and straddling the printhead die and interconnection board, the legs defining the width of the cavity and having a height defining a depth of the cavity.

Claim 14

The printhead of claim 11, wherein the constraining means is a dam bar mounted on an undersurface of the manifold and extending substantially across the cavity in the transverse direction.

Claim 15

The printhead of claim 12, wherein a length of the dam bar in the transverse direction is less than the width of the cavity to define at least one space between the dam bar and the legs.

Claim 16

The printhead of claim 12, wherein the dam bar extends from the undersurface of the cavity to a depth less than the depth of the cavity to define a space between the dam bar and substrate.

Claim 17

The printhead of claim 9, wherein the through hole is centrally located in the transvere direction between the heater section and the interconnection board.

Claim 18

The printhead of claim 11, wherein a length in the traverse direction of the printhead is less than the width of the cavity to define at least one air gap between the legs and the printhead die, the air gap being sealed by the encapsulant.

Claim 19

A thermal ink jet printhead comprising: a heat sinking substrate; a printhead die mounted on one side of the substrate and comprising a channel section with an ink inlet and a heater section with a row of wire bond pads; an interconnection board bonded to the substrate on the same side as said printhead die and adjacent therewith, the interconnection board having a corresponding row of wire bond pads; a plurality of wire bonds electrically interconnecting the row of wire bond pads on the heater section and the interconnection board; a manifold mounted to the substrate and defining therein a cavity for reception of the printhead die, interconnection board and plurality of wire bonds, the manifold including an ink inlet for communication with the ink inlet of the channel section and a through hole, said manifold further including a dam bar mounted on the undersurface of the manifold and extending substantially across the cavity in a transverse direction; and the through hole communicating with the cavity and the cavity containing an encapsulant injected through the through hole for encapsulating the wire bonds, sealing air gaps between the manifold and the printhead die, and bonding the manifold to the substrate, wherein the channel section, heater section, through hole and interconnection board define a longitudinal direction of the substrate, the one side of the through hole defining a forward direction and the other side of the through hole defining a rearward direction, the cavity having a width in the transverse direction perpendicular to the longitudinal direction, said dam bar constraining the flow of encapsulant in the rearward direction.

Claim 20

A thermal ink jet printhead comprising: a heat sinking substrate; a printhead die mounted on one side of the substrate and comprising a channel section with an ink inlet and a heater section with a row of wire bond pads; an interconnection board bonded to the substrate on the same side as said printhead die and adjacent therewith, the interconnection board having a corresponding row of wire bond pads; a plurality of wire bonds electrically interconnecting the row of wire bond pads on the heater section and the interconnection board; a manifold mounted to the substrate and defining therein a cavity for reception of the printhead die, interconnection board and plurality of wire bonds, the manifold including an ink inlet for communication with the ink inlet of the channel section and a through hole, said manifold further including a dam bar mounted on the undersurface of the manifold and extending substantially across the cavity in a transverse direction; and the through hole communicating with the cavity and the cavity containing an encapsulant injected through the through hole for encapsulating the wire bonds, sealing air gaps between the manifold and the printhead die, and bonding the manifold to the substrate, wherein the channel section, heater section, through hole and interconnection board define a longitudinal direction of the substrate, the one side of the through hole defining a forward direction and the other side of the through hole defining a rearward direction, the cavity having a width in the transverse direction perpendicular to the longitudinal direction, said dam bar constraining the flow of encapsulant in the rearward direction.

Claim 23

The method of claim 18, wherein the through hole is located on said substrate and said step of injecting a liquid encapsulant is performed by injecting the encapsulant from a bottom of the substrate into said cavity.

Claim 24

The method of claim 18, wherein the through hole is located on said manifold and said step of injecting a liquid encapsulant is performed by injecting the encapsulant from a top of the manifold into said cavity.