# US 2021/0276340 A1 · Inkjet printing apparatus and method of controlling inkjet printing apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0276340 A1 - Document ID: US20210276340A1 - Status: Published application - Kind: A1 - Application number: 17/328,190 - Filed: 2021-05-24 - Published: 2021-09-09 - Earliest claimed: 2018-10-05 - Assignees: Canon Kabushiki Kaisha - Applicants: Canon Kabushiki Kaisha - Inventors: Takatoshi Nakano; Yoshinori Nakagawa; Atsushi Takahashi; Takuya Fukasawa - Web page: https://patentgrep.com/patent/US20210276340A1 ## CPC - B41J 2/19: for removing air bubbles - B41J 29/38: Drives, motors, controls or automatic cut-off devices for the entire printing mechanism - B41J 2/14: Structure thereof {only for on-demand ink jet heads} - B41J 2/175: Ink supply systems {; Circuit parts therefor} - B41J 2/18: Ink recirculation systems - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS ## Abstract An inkjet printing apparatus is provided with a tank that stores ink, a print head that performs print operation by ejecting ink supplied from the tank, a circulation unit that establishes a circulating state to circulate ink in a circulation path if print operation is performed and establishes a stopped state to stop circulation of ink if print operation is terminated, and a deaeration unit that performs deaeration operation to deaerate ink inside the circulation path. The apparatus includes an estimation unit that estimates a dissolved gas amount in ink inside the circulation path based on dissolved gas amounts increased in the circulating state and in the stopped state, respectively, and a control unit that causes the deaeration unit to execute deaeration operation after completion of print operation if the dissolved gas amount estimated by the estimation unit exceeds a predetermined threshold. ## Claims ### Claim at position 1 1-18. (canceled) ### Claim 19 A printing apparatus comprising: a tank configured to store liquid to be supplied to a print head which ejects the liquid based on print data to perform print operation; a circulation unit configured to establish a circulating state in which the liquid is put into circulation in a circulation path including the tank and the print head, and to establish a stopped state in which the circulation of the liquid in the circulation path is stopped; a deaeration unit configured to perform deaeration operation to deaerate the liquid inside the circulation path; a control unit configured to cause the deaeration unit to perform the deaeration operation in a case where a duration of the stopped state exceeds a threshold value. ### Claim 20 (depends on 19) The printing apparatus according to claim 19, wherein the duration of the stopped state is an elapsed time from a completion of previous print operation. ### Claim 21 (depends on 19) The printing apparatus according to claim 19, wherein the deaeratin unit deaerates the liquid inside the tank. ### Claim 22 (depends on 19) The printing apparatus according to claim 19, wherein the print head performs printing operation in a state where the circulation unit establishes the circulating state. ### Claim 23 (depends on 19) The printing apparatus according to claim 19, wherein the control unit controls the deaeration unit to perform the deaeration operation after completion of print operation. ### Claim 24 (depends on 19) The printing apparatus according to claim 19, wherein the print head includes an ejection port, a printing element for generating energy used for ejecting the liquid, and a pressure chamber which is an area facing to the printing element, the ejection port ejecting the liquid supplied through the pressure chamber, and wherein the circulation path includes the pressure chamber. ### Claim 25 (depends on 19) The printing apparatus according to claim 19, further comprising: a supply flow path configured to supply liquid to the print head; and a collection flow path configured to collect liquid from the print head, wherein the circulation path includes the supply flow path and the collection flow path. ### Claim 26 A circulation apparatus comprising: a circulation unit configured to establish a circulating state in which liquid is put into circulation in a circulation path including a tank configured to store liquid and a print head configured to eject the liquid based on print data to perform print operation, and to establish a stopped state in which the circulation of the liquid in the circulation path is stopped, and a deaeration unit configured to perform deaeration operation to deaerate the liquid inside the circulation path, wherein the deaeration unit performs the deaeration operation in a case where a duration of the stopped state exceeds a threshold value. ### Claim 27 (depends on 26) The circulation apparatus according to claim 26, wherein the duration of the stopped state is an elapsed time from a completion of previous print operation. ### Claim 28 (depends on 26) The circulation apparatus according to claim 26, wherein the deaeratin unit deaerates the liquid inside the tank. ### Claim 29 (depends on 26) The circulation apparatus according to claim 26, wherein the deaeration unit performs the deaeration operation after completion of print operation. ### Claim 30 A control method of a printing apparatus including a tank configured to store liquid to be supplied to a print head which ejects the liquid based on print data to perform print operation, and a circulation unit configured to establish a circulating state in which the liquid is put into circulation in a circulation path including the tank and the print head, and to establish a stopped state in which the circulation of the liquid in the circulation path is stopped, the control method comprising: deaerating the liquid inside the circulation path in a case where a duration of the stopped state exceeds a threshold value. ### Claim 31 (depends on 30) The control method according to claim 30, wherein the duration of the stopped state is an elapsed time from a completion of previous print operation.