Inkjet printhead assembly

A method for forming a printhead, comprising:

• providing a substrate comprised of one or more porous materials adapted to allow fluid to flow through the substrate from a first portion of the substrate to a second portion of the substrate;
• connecting a fluid supply to the first portion of the substrate;
• and
• forming one or more fluid ejection mechanisms on a second portion of the substrate, wherein each fluid ejection mechanism is configured to receive fluid flowed through the substrate from the fluid supply and selectively eject the received fluid away from the substrate and wherein forming one or more fluid ejector mechanisms includes
• forming one or more firing chambers on the substrate, each firing chamber having a central region and a periphery at least partially surrounding the central region, and
• forming one or more firing resistors in at least one of the firing chambers, wherein the one or more firing resistors are disposed adjacent the periphery and spaced-apart from the central region of the firing chamber.

A printhead structure, comprising:

• a substrate with a first side and a second side;
• a fluid supply connected to the first side of the substrate;
• one or more firing chambers disposed on the second side of the substrate and configured to receive fluid from the fluid supply, wherein each chamber includes a central region and a peripheral region at least partially surrounding the central region;
• and
• one or more firing resistors disposed within at least one of the chambers and controllable to eject fluid out of the at least one chamber, wherein the one or more resistors are disposed in the peripheral region and spaced-apart from the central region.

A printhead structure, comprising:

• a substrate;
• a fluid supply connected to the substrate;
• one or more firing chambers disposed on the substrate and configured to receive fluid from the fluid supply, wherein each firing chamber includes an orifice, a bottom surface, and one or more side walls extending generally upward from the bottom surface toward the orifice;
• and
• one or more firing resistors disposed on one or more of the side walls within each of the firing chambers;
• wherein the substrate and the bottom surface of each firing chamber includes one or more openings adapted to allow fluid to flow from the fluid supply, through the substrate and bottom surface, and into the firing chamber.

A fluid ejection device comprising:

• a substrate having a first region and a second region;
• a fluid supply connected to the first region;
• and
• one or more fluid ejection mechanisms disposed on the substrate adjacent the second region, each adapted to selectively eject an amount of fluid away from the substrate;
• wherein each fluid ejection mechanism includes:
• a firing chamber having a central region at least partially surrounded by a periphery, and
• one or more firing resistors disposed within the chamber adjacent the periphery and spaced-apart from the central region;
• and
• wherein the substrate is sufficiently porous between the first region and the second region to allow fluid to flow through the substrate from the fluid supply to the one or more fluid ejection mechanisms.