# US 12,109,808 B2 · Recording apparatus and control method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,109,808 B2 - Document ID: US12109808B2 - Status: Granted - Kind: B2 - Application number: 17/858,156 - Filed: 2022-07-06 - Published: 2023-01-12 - Granted: 2024-10-08 - Earliest claimed: 2021-07-07 - Assignees: Canon Kabushiki Kaisha - Applicants: Canon Kabushiki Kaisha - Inventors: Yoshihiro Hamada; Takahiro Matsui; Takatsugu Moriya; Nobuyuki Hirayama - Web page: https://patentgrep.com/patent/US12109808B2 ## CPC - B41J 2/04563: {detecting head temperature; Ink temperature} - B41J 2/14024: {Assembling head parts} - B41J 2/0458: {controlling heads based on heating elements forming bubbles} - B41J 2/1404: {Geometrical characteristics} - B41J 2/14072: {Electrical connections, e.g. details on electrodes, connecting the chip to the outside...} - B41J 2/14129: {Layer structure} - B41J 2/14145: {Structure of the manifold} - B41J 2202/12: with ink circulating through the whole print head - B41J 2202/19: Assembling head units - B41J 2202/20: Modules - B41J 2202/21: Line printing - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS ## Abstract A recording apparatus includes: a liquid ejection head including a heating element, a first protection layer that blocks contact between the heating element and liquid, a second protection layer that covers at least a portion of the first protection layer to be heated by the heating element and that functions as a first electrode, a second electrode that is electrically connected to the first electrode through the liquid, an ejection port that ejects the liquid, and a temperature detection element that corresponds to the heating element, and a detection unit configured to detect a feature point in a temperature curve that indicates a relationship between time and temperature, in which a combination of a potential set for the first electrode and a potential set for the second electrode in a case where printing is performed varies from that in a case where the detection unit detects the feature point. ## Claims ### Claim 1 A recording apparatus comprising: a liquid ejection head including (1) a heating element that generates thermal energy required to eject liquid, the liquid including pigment charged to a negative potential, (2) a first protection layer that blocks contact between the heating element and the liquid, (3) a second protection layer that covers at least a portion of the first protection layer to be heated by the heating element and that functions as a first electrode, (4) a second electrode that is electrically connected to the first electrode through the liquid, (5) an ejection port that ejects the liquid, and (6) a temperature detection element that corresponds to the heating element; a detection unit configured to detect a feature point in a temperature curve that is obtained by the temperature detection element and that indicates a relationship between time and temperature; and a determination unit configured to determine whether or not the liquid is normally ejected from the ejection port based on whether or not the detection unit has detected the feature point in the temperature curve, wherein the recording apparatus has (1) a non-ejection determination mode using the determination unit and (2) a printing mode in which printing is performed without using the determination unit, wherein in the printing mode, a potential set for the first electrode and a potential set for the second electrode are controlled so that an electric field that reduces a presence ratio of the pigment near a surface of the second protection layer is formed between the first electrode and the second electrode, and wherein in the non-ejection determination mode, the potential set for the first electrode and the potential set for the second electrode are made different from that under potential control in the printing mode. ### Claim 2 (depends on 1) The recording apparatus according to claim 1, wherein the detection unit detects the feature point by performing a differential operation on the temperature curve. ### Claim 3 (depends on 1) The recording apparatus according to claim 1, wherein the recording apparatus operates in the printing mode in a case where printing is to be performed, and operates in the non-ejection determination mode in a case where the feature point is to be detected. ### Claim 4 (depends on 3) The recording apparatus according to claim 3, wherein, in the case where the potential of the first electrode and the potential of the second electrode are to be switched in switching between the printing mode and the non-ejection determination mode, the potential of the first electrode is changed before the potential of the second electrode. ### Claim 5 (depends on 3) The recording apparatus according to claim 3, wherein, in switching between the printing mode and the non-ejection determination mode, the potential of the second electrode is not changed and only the potential of the first electrode is changed. ### Claim 6 (depends on 3) The recording apparatus according to claim 3, wherein a potential difference between the potential set for the first electrode and the potential set for the second electrode in the printing mode is larger than that in the non-ejection determination mode. ### Claim 7 (depends on 1) The recording apparatus according to claim 1, wherein the liquid ejection head further includes a pressure chamber, wherein a supply flow passage that supplies the liquid to the pressure chamber and a collection flow passage that collects the liquid from the pressure chamber communicate with the pressure chamber, and wherein the liquid circulates by flowing through the supply flow passage, the pressure chamber, and the collection flow passage in this order. ### Claim 8 (depends on 1) The recording apparatus according to claim 1, wherein the heating element and the temperature detection element are provided at different positions in a direction in which the liquid is ejected, and wherein the temperature detection element has a meandering shape. ### Claim 9 (depends on 1) The recording apparatus according to claim 1, wherein, in switching between the printing mode and the non-ejection determination mode, the potential of the second electrode is not changed and only the potential of the first electrode is changed. ### Claim 10 (depends on 1) The recording apparatus according to claim 1, wherein, in switching between the printing mode and the non-ejection determination mode, the potential of the first electrode is not changed and only the potential of the second electrode is changed. ### Claim 11 (depends on 1) The recording apparatus according to claim 1, wherein, in switching between the printing mode and the non-ejection determination mode, the potential of the first electrode is changed and the potential of the second electrode is changed. ### Claim 12 A control method of a recording apparatus, the recording apparatus including a liquid ejection head including (1) a heating element that generates thermal energy required to eject liquid, the liquid including pigment charged to a negative potential, (2) a first protection layer that blocks contact between the heating element and the liquid, (3) a second protection layer that covers at least a portion of the first protection layer to be heated by the heating element and that functions as a first electrode, (4) a second electrode that is electrically connected to the first electrode through the liquid, (5) an ejection port that ejects the liquid, and (6) a temperature detection element that corresponds to the heating element, the control method comprising: detecting a feature point in a temperature curve that is obtained by the temperature detection element and that indicates a relationship between time and temperature, wherein the recording apparatus has (1) a non-ejection determination mode in which a determination as to whether or not the liquid is normally ejected from the ejection port is made, based on whether or not the detecting has detected the feature point in the temperature curve, and (2) a printing mode in which printing is performed without making the determination, wherein in the printing mode, a potential set for the first electrode and a potential set for the second electrode are controlled so that an electric field that reduces a presence ratio of the pigment near a surface of the second protection layer is formed between the first electrode and the second electrode, and wherein in the non-ejection determination mode, the potential set for the first electrode and the potential set for the second electrode are made different from that under potential control in the printing mode. ### Claim 13 (depends on 12) The control method according to claim 12, wherein, in switching between the printing mode and the non-ejection determination mode, the potential of the second electrode is not changed and only the potential of the first electrode is changed. ### Claim 14 (depends on 12) The control method according to claim 12, wherein, in switching between the printing mode and the non-ejection determination mode, the potential of the first electrode is not changed and only the potential of the second electrode is changed. ### Claim 15 (depends on 12) The control method according to claim 12, wherein, in switching between the printing mode and the non-ejection determination mode, the potential of the first electrode is changed and the potential of the second electrode is changed.