# US 8,465,139 B2 · Thermal degassing device for inkjet printer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,465,139 B2 - Document ID: US8465139B2 - Status: Granted - Kind: B2 - Application number: 12/897,902 - Filed: 2010-10-05 - Published: 2012-04-05 - Granted: 2013-06-18 - Earliest claimed: 2010-10-05 - Assignees: Eastman Kodak Company - Applicants: Brian G. Price; Gary A. Kneezel - Inventors: Brian G. Price; Gary A. Kneezel - Web page: https://patentgrep.com/patent/US8465139B2 ## CPC - B41J 2/19: for removing air bubbles - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS ## Abstract An inkjet printhead having a drop ejector array, an ink passageway for providing ink to the drop ejector array, and a thermally actuated degassing unit. The degassing unit itself includes a body enclosing an air chamber, a check valve configured to allow air to vent from the air chamber to ambient when the pressure in the air chamber exceeds ambient air pressure by a predetermined amount. The thermal degassing unit includes a thermally-induced pressure build-up time to increase the pressure in the air chamber. The air chamber is allowed to cool which causes internal pressure to drop below ambient and draws gas out of the ink. ## Claims ### Claim 1 An inkjet printhead comprising: a drop ejector array; an ink passageway for providing ink to the drop ejector array; and a thermally actuated degassing unit including: a body enclosing an air chamber; a check valve configured to allow air to vent from the air chamber to ambient when the pressure in the air chamber exceeds ambient air pressure by a predetermined pressure; a heating element inside the air chamber; and a membrane including a first side and a second side opposite the first side, wherein the first side faces the air chamber and the second side faces the ink passageway. ### Claim 2 (depends on 1) The inkjet printhead of claim 1 further comprising a holder for a detachable ink tank, the holder including: an ink port for receiving ink from the detachable ink tank; and a surface including an opening connected to the ink passageway, wherein the membrane is adhered to the surface and wherein the membrane covers the opening. ### Claim 3 (depends on 2) The inkjet printhead of claim 2 wherein the surface further includes a recess to accommodate the membrane. ### Claim 4 (depends on 2) The inkjet printhead of claim 2, wherein the ink passageway is a first ink passageway and the opening is a first opening, the inkjet printhead further comprising a second ink passageway and the holder further comprising a second opening connected to the second ink passageway, wherein the membrane covers both the first opening and the second opening. ### Claim 5 (depends on 4) The inkjet printhead of claim 4 further comprising an ink manifold including: a plurality of inlets disposed at a first spacing from each other for connecting to a corresponding plurality of ink ports and a plurality of outlets disposed at a second spacing for connecting to a corresponding plurality of drop ejector arrays, wherein the second spacing is less than the first spacing. ### Claim 6 (depends on 2) The inkjet printhead of claim 2 further comprising a detachable ink tank mounted in the holder, wherein the thermally actuated degassing unit is disposed between the drop ejector array and the ink tank. ### Claim 7 (depends on 1) The inkjet printhead of claim 1 wherein a thickness of the membrane is between 25 microns and 300 microns. ### Claim 8 (depends on 1) The inkjet printhead of claim 1, the membrane including a characteristic time for a sufficient quantity of air to diffuse through the membrane to change the pressure in the air chamber by a predetermined amount, and the thermal degassing unit including a thermally-induced pressure build-up time to increase the pressure in the air chamber by the predetermined amount, wherein the characteristic time is greater than the thermally-induced pressure build-up time. ### Claim 9 (depends on 8) The inkjet printhead of claim 8, wherein the check valve includes a cracking pressure that is greater than 1.1 atmospheres. ### Claim 10 (depends on 8) The inkjet printhead of claim 8, wherein for a pressure change in the air chamber of 0.1 atmospheres, the characteristic time for air diffusion through the membrane is greater than five seconds and less than 500 seconds. ### Claim 11 (depends on 8) The inkjet printhead of claim 8, wherein for a pressure change in the air chamber of 0.1 atmospheres, the thermally-induced pressure build-up time is greater than 0.5 second and less than 100 seconds. ### Claim 12 (depends on 1) The inkjet printhead of claim 1, the body including a first end and a second end opposite the first end, wherein the heating element is disposed proximate the first end and the check valve is disposed proximate the second end. ### Claim 13 (depends on 1) The inkjet printhead of claim 1, the air chamber including a first portion having a first height and a second height that is greater than the first height, wherein the heating element and the check valve are proximate the second portion of the air chamber. ### Claim 14 (depends on 13) The inkjet printhead of claim 13, wherein the membrane is disposed proximate the first portion of the air chamber. ### Claim 15 (depends on 1) The inkjet printhead of claim 1, wherein the heating element comprises a thermoelectric cooling device. ### Claim 16 An inkjet printer comprising: a drop ejector array; an ink passageway for providing ink to the drop ejector array; a thermally actuated degassing unit including: a body enclosing an air chamber; a check valve configured to allow air to vent from the air chamber to ambient when the pressure in the air chamber exceeds ambient air pressure by a predetermined pressure; a heating element inside the air chamber; and a membrane including a first side and a second side opposite the first side, wherein the first side faces the air chamber and the second side faces the ink passageway; and a controller for controlling operations of the inkjet printer. ### Claim 17 (depends on 16) The inkjet printer of claim 16 further comprising an inkjet printhead including: the drop ejector array; the ink passageway; and the thermally actuated degassing unit. ### Claim 18 (depends on 16) The inkjet printer of claim 16 further comprising a carriage for moving the drop ejector array during printing of an image, wherein the thermally actuated degassing unit is configured to be moved by the carriage. ### Claim 19 (depends on 16) The inkjet printer of claim 16, wherein the check valve includes a cracking pressure that is greater than 1.1 atmospheres. ### Claim 20 (depends on 16) The inkjet printer of claim 16, wherein the heating element is suspended within the air chamber such that the heating element does not touch the body of the air chamber. ### Claim 21 (depends on 16) The inkjet printer of claim 16, wherein the mass of the heating element inside the air chamber is less than one gram. ### Claim 22 (depends on 16) The inkjet printer of claim 16, wherein the membrane is in contact with ink in the ink passageway. ### Claim 23 (depends on 16) The inkjet printer of claim 16, the air chamber including a first portion having a first height and a second portion having a second height that is greater than the first height, wherein the heating element and the check valve are proximate the second portion of the air chamber. ### Claim 24 (depends on 23) The inkjet printer of claim 23, wherein the membrane is disposed proximate the first portion of the air chamber. ### Claim 25 (depends on 16) The inkjet printer of claim 16, wherein the heating element comprises a thermoelectric cooling device.