# US 11,999,167 B2 · Inkjet printing apparatus and recovery method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,999,167 B2 - Document ID: US11999167B2 - Status: Granted - Kind: B2 - Application number: 18/193,036 - Filed: 2023-03-30 - Published: 2023-07-27 - Granted: 2024-06-04 - Earliest claimed: 2018-10-05 - Assignees: Canon Kabushiki Kaisha - Applicants: Canon Kabushiki Kaisha - Inventors: Yoshinori Nakagawa; Takatoshi Nakano; Atsushi Takahashi; Takuya Fukasawa - Web page: https://patentgrep.com/patent/US11999167B2 ## CPC - B41J 2/16517: {Cleaning of print head nozzles (B41J2/16505, B41J2/1707 take precedence)} - B41J 2/16532: {by applying vacuum only} - B41J 2/16508: {connected with the printer frame} - B41J 2/16588: {Print heads movable towards the cleaning unit} - B41J 2/18: Ink recirculation systems - B41J 29/02: Framework - B41J 29/38: Drives, motors, controls or automatic cut-off devices for the entire printing mechanism - B41J 2202/12: with ink circulating through the whole print head - 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 Provided are an inkjet printing apparatus and a recovery method capable of suppressing ink thickening in the ejection openings in the suction process for the ejection openings. A vacuum wiper is moved being in contact with the ejection opening surface of the print head to perform a vacuum wiping process for the arrayed ejection openings sequentially. Ink is circulated in flow paths including the flow paths communicating with the ejection openings for which the vacuum wiping process has been finished. ## Claims ### Claim 1 An inkjet printing apparatus comprising: a printing unit that includes arrayed multiple ejection openings configured to eject liquid and multiple flow paths each of which is communicating with the ejection opening, and that is configured to perform a printing process for printing an image on a print medium according to print data; a discharge unit configured to perform a discharge process for discharging liquid from the ejection openings, wherein the discharge process is different from the printing process; and a circulation unit configured to circulate liquid supplied to the printing unit, through the flow paths; wherein while the discharge process is performed by the discharge unit, the circulation unit circulates liquid in at least one of the flow paths. ### Claim 2 (depends on 1) The inkjet printing apparatus according to claim 1, further comprising: a supply flow path for supplying liquid from a liquid storing unit to the print head; and a collection flow path for collecting the liquid from the print head to the liquid storing unit; wherein the circulation unit circulates liquid in a circulation path including the supply flow path, the flow path, and the collection flow path. ### Claim 3 (depends on 1) The inkjet printing apparatus according to claim 1, wherein the printing unit includes arrayed multiple ejection openings for each of multiple kinds of liquids and multiple flow paths respectively communicating with the ejection openings, wherein the circulation unit is capable of circulating liquid in the flow paths provided for each of the multiple kinds of liquids, and wherein the circulation unit circulates liquid in at least one flow path of the multiple flow paths while the discharge process is performed by the discharge unit. ### Claim 4 (depends on 3) The inkjet printing apparatus according to claim 3, wherein the flow path in which liquid is circulated is a flow path for a liquid in which the degree of increase in viscosity due to evaporation of a liquid component in the liquid under a specified condition is higher than or equal to a specified degree. ### Claim 5 (depends on 3) The inkjet printing apparatus according to claim 3, wherein the circulation unit circulates liquid in at least one kind of flow paths while the discharge process is performed by the discharge unit. ### Claim 6 (depends on 3) The inkjet printing apparatus according to claim 3, wherein the flow paths of all the ejection openings for ejecting liquid of the same color are communicated with each other. ### Claim 7 (depends on 1) The inkjet printing apparatus according to claim 1, wherein the ejection openings of the printing unit include ejection openings with a specified diameter, and ejection openings with a diameter smaller than the specified diameter, and wherein the circulation unit circulates liquid in the flow paths communicating with the ejection openings with the diameter smaller than the specified diameter. ### Claim 8 (depends on 1) The inkjet printing apparatus according to claim 1, wherein the circulation unit circulates liquid such that the liquid passes through the flow paths communicating with all the ejection openings of the printing unit while the discharge unit performs the discharge process. ### Claim 9 (depends on 1) The inkjet printing apparatus according to claim 1, wherein the discharge unit sucks the liquid, wherein the discharge process is a process in which the discharge unit sucks the liquid from the ejection openings. ### Claim 10 (depends on 1) The inkjet printing apparatus according to claim 1, comprising a conveyance unit configured to convey the print medium in first direction, wherein the multiple ejection openings are arrayed in a direction intersecting the first direction by a length corresponding to a width of the print medium. ### Claim 11 (depends on 1) The inkjet printing apparatus according to claim 1, wherein the printing unit includes a printing element configured to eject liquid from the ejection opening in performing the printing process, and the discharge unit is different from the printing element. ### Claim 12 (depends on 11) The inkjet printing apparatus according to claim 11, wherein the discharge unit is a unit provided outside a print head. ### Claim 13 (depends on 1) The inkjet printing apparatus according to claim 1, wherein the discharge process is from a start to an end of a liquid discharge from the multiple ejection openings. ### Claim 14 (depends on 1) The inkjet printing apparatus according to claim 1, the discharge unit performs the discharge process by causing the multiple ejection openings to discharge liquid sequentially while moving relative to the printing unit. ### Claim 15 (depends on 1) The inkjet printing apparatus according to claim 1, wherein during the discharge process, the circulation unit circulates liquid in at least the flow paths communicating with the ejection openings for which the discharge by the discharge unit has been finished while the discharge unit discharges liquid from the ejection openings for which the discharge by the discharge unit has not been finished. ### Claim 16 (depends on 1) The inkjet printing apparatus according to claim 1, comprising a detection unit configured to detect the relative position between the print head and the suction unit, and a control unit determines the discharge process by the discharge unit has been finished, based on the position detected by the detection unit, and performs the preliminary ejection from the ejection openings for which the control unit has determined that the discharge process has been finished. ### Claim 17 An inkjet printing apparatus comprising: a printing unit that includes arrayed multiple ejection openings configured to eject liquid and that is configured to perform a printing process for printing an image according to print data, a discharge unit configured to perform a discharge process for discharging liquid from the ejection openings, wherein the discharge process is different from the printing process; and wherein while the discharge process is performed by the discharge unit, the printing unit performs preliminary ejection, which is liquid ejection different from ejection of the printing process. ### Claim 18 (depends on 17) The inkjet printing apparatus according to claim 17, wherein the printing unit includes multiple substrates disposed side by side, each substrate including an array of the ejection openings, and wherein the printing unit performs the preliminary ejection for the ejection openings on a substrate by substrate basis. ### Claim 19 (depends on 17) The inkjet printing apparatus according to claim 17, wherein during the discharge process, the printing unit performs preliminary ejection from at least the ejection openings for which the discharge by the discharge unit has been finished while the discharge unit discharges liquid from the ejection openings for which the discharge by the discharge unit has not been finished. ### Claim 20 (depends on 17) The inkjet printing apparatus according to claim 17, wherein the printing unit includes arrayed multiple ejection openings for each of multiple kinds of liquids and multiple flow paths respectively communicating with the ejection openings, wherein the circulation unit is capable of circulating liquid in the flow paths provided for each of the multiple kinds of liquids, and wherein the circulation unit circulates liquid in at least one flow path of the multiple flow paths while the discharge process is performed by the discharge unit. ### Claim 21 (depends on 17) The inkjet printing apparatus according to claim 17, comprising a conveyance unit configured to convey the print medium in first direction, wherein the multiple ejection openings are arrayed in a direction intersecting the first direction by a length corresponding to a width of the print medium. ### Claim 22 (depends on 17) The inkjet printing apparatus according to claim 17, wherein the printing unit includes a printing element configured to eject liquid from the ejection opening in performing the printing process, and the discharge unit is different from the printing element. ### Claim 23 (depends on 22) The inkjet printing apparatus according to claim 22, wherein the discharge unit is a unit provided outside a print head. ### Claim 24 (depends on 17) The inkjet printing apparatus according to claim 17, the discharge process is from a start to an end of a liquid discharge from the multiple ejection openings. ### Claim 25 (depends on 17) The inkjet printing apparatus according to claim 17, the discharge unit performs the discharge process by causing the multiple ejection openings to discharge liquid sequentially while moving relative to the printing unit. ### Claim 26 A recovery method comprising: moving at least one of a discharge unit and a printing unit relatively with respect to the other, the printing unit including arrayed multiple ejection openings configured to perform a printing process for ejecting liquid according to print data, the discharge unit being at a position facing an ejection opening surface of the printing unit, on which surface the ejection openings are formed; and discharging liquid from the ejection openings in order with the discharge unit, wherein the discharging liquid is different from the printing process, wherein while the discharge is performed for the ejection openings with the discharge unit, liquid is circulated in at least one flow path of the printing unit. ### Claim 27 (depends on 26) The recovery method according to claim 26, wherein a liquid supplied to the print head configured to eject multiple kinds of liquids from different ejection openings of the ejection openings, the ejection opening for each of the multiple kinds of liquids having a different flow path, is circulated such that the liquid passes through at least one flow path of the flow paths respectively provided for the multiple kinds of liquids. ### Claim 28 (depends on 27) The recovery method according to claim 27, wherein the flow path is a flow path for a liquid in which the degree of increase in viscosity due to evaporation of a liquid component in the liquid under a specified condition is higher than or equal to a specified degree. ### Claim 29 (depends on 26) The recovery method according to claim 26, wherein in a case where the discharge unit has finished discharge for some of the ejection openings, a circulation unit circulates liquid such that the liquid passes through the flow paths communicating with all the ejection openings of the print head. ### Claim 30 A recovery method comprising: moving at least one of a discharge unit and a printing unit relatively with respect to the other, the printing unit including arrayed multiple ejection openings and being configured to perform a printing process for ejecting liquid according to print data, the discharge unit being at a position facing an ejection opening surface of the printing unit, on which the ejection openings are formed; and discharging liquid from the ejection openings in order with the discharge unit, wherein the discharging liquid is different from the printing process, wherein while the discharge is performed for the ejection openings with the discharge unit, preliminary ejection, which is liquid ejection different from ejection of the printing process is performed from the printing unit. ### Claim 31 An inkjet printing apparatus comprising: a printing unit that includes arrayed multiple ejection openings configured to eject liquid, and that is configured to perform a printing process for printing an image on a print medium according to print data; multiple flow paths, each of which has a first path for flowing the liquid from the outside of the printing unit to the inside of the printing unit and a second path for flowing the liquid from the inside of the printing unit to the outside of the printing unit; a discharge unit configured to perform a discharge process for discharging liquid from the ejection openings, wherein the discharge process is different from the printing process; and a circulation unit configured to circulate liquid supplied to the printing unit, through the flow paths; wherein while the discharge process is performed by the discharge unit, the control unit circulates liquid in at least one of the flow paths. ### Claim 32 (depends on 31) The inkjet printing apparatus according to claim 31, wherein the printing unit includes arrayed multiple ejection openings for each of multiple kinds of liquids, wherein the multiple flow paths are provided for each kind of liquid, wherein the circulation unit is capable of circulating liquid in the flow paths provided for each of the multiple kinds of liquids, and wherein the control unit makes the circulation unit circulate liquid in at least one flow path of the multiple flow paths during the discharge process. ### Claim 33 (depends on 31) The inkjet printing apparatus according to claim 31, wherein the first path is for supplying liquid from the liquid storage unit to the printing unit, wherein the second path is for collecting liquid from the printing unit to the liquid storage unit, wherein the inkjet printing apparatus further comprises: a supply flow path for supplying liquid from a liquid storing unit to the print head; and a collection flow path for collecting the liquid from the print head to the liquid storing unit, and wherein the circulation unit circulates liquid in a circulation path including the supply flow path, the flow path, and the collection flow path. ### Claim 34 (depends on 31) The inkjet printing apparatus according to claim 31, wherein the printing unit includes arrayed multiple ejection openings for each of multiple kinds of liquids and multiple flow paths respectively communicating with the ejection openings, wherein the circulation unit is capable of circulating liquid in the flow paths provided for each of the multiple kinds of liquids, and wherein the circulation unit circulates liquid in at least one flow path of the multiple flow paths while the discharge process is performed by the discharge unit. ### Claim 35 (depends on 34) The inkjet printing apparatus according to claim 34, wherein the flow path in which liquid is circulated is a flow path for a liquid in which the degree of increase in viscosity due to evaporation of a liquid component in the liquid under a specified condition is higher than or equal to a specified degree. ### Claim 36 (depends on 34) The inkjet printing apparatus according to claim 34, wherein the circulation unit circulates liquid in at least one kind of flow paths while the discharge process is performed by the discharge unit. ### Claim 37 (depends on 34) The inkjet printing apparatus according to claim 34, wherein the flow paths of all the ejection openings for ejecting liquid of the same color are communicated with each other. ### Claim 38 (depends on 31) The inkjet printing apparatus according to claim 31, wherein the discharge unit sucks the liquid, wherein the discharge process is a process in which the discharge unit sucks the liquid from the ejection openings. ### Claim 39 (depends on 31) The inkjet printing apparatus according to claim 31, comprising a conveyance unit configured to convey the print medium in first direction, wherein the multiple ejection openings are arrayed in a direction intersecting the first direction by a length corresponding to a width of the print medium. ### Claim 40 (depends on 31) The inkjet printing apparatus according to claim 31, wherein the printing unit includes a printing element configured to eject liquid from the ejection opening in performing the printing process, and the discharge unit is different from the printing element. ### Claim 41 (depends on 40) The inkjet printing apparatus according to claim 40, wherein the discharge unit is a unit provided outside a print head. ### Claim 42 (depends on 31) The inkjet printing apparatus according to claim 31, the discharge process is from a start to an end of a liquid discharge from the multiple ejection openings. ### Claim 43 (depends on 31) The inkjet printing apparatus according to claim 31, the discharge unit performs the discharge process by causing the multiple ejection openings to discharge liquid sequentially while moving relative to the printing unit. ### Claim 44 (depends on 31) The inkjet printing apparatus according to claim 31, wherein during the discharge process, the circulation unit circulates liquid in at least the flow paths communicating with the ejection openings for which the discharge by the discharge unit has been finished while the discharge unit discharges liquid from the ejection openings for which the discharge by the discharge unit has not been finished. ### Claim 45 (depends on 31) The inkjet printing apparatus according to claim 31, comprising a detection unit configured to detect the relative position between the print head and the suction unit, and a control unit determines the discharge process by the discharge unit has been finished, based on the position detected by the detection unit, and performs the preliminary ejection from the ejection openings for which the control unit has determined that the discharge process has been finished. ### Claim 46 An inkjet printing apparatus comprising: a printing unit that includes arrayed multiple ejection openings configured to eject liquid, and that is configured to perform a printing process for printing an image on a print medium according to print data; multiple flow paths, each of which has a first path for flowing the liquid from the outside of the printing unit to the inside of the printing unit and a second path for flowing the liquid from the inside of the printing unit to the outside of the printing unit; a discharge unit configured to perform a discharge process for discharging liquid from the ejection openings, wherein the discharge process is different from the printing process; and wherein while the discharge process is performed by the discharge unit, the printing unit performs preliminary ejection, which is liquid ejection different from ejection of the printing process. ### Claim 47 (depends on 46) The inkjet printing apparatus according to claim 46, wherein the printing unit includes arrayed multiple ejection openings for each of multiple kinds of liquids, wherein the multiple flow paths are provided for each kind of liquid, wherein the circulation unit is capable of circulating liquid in the flow paths provided for each of the multiple kinds of liquids, and wherein the circulation unit circulates liquid in at least one flow path of the multiple flow paths during the discharge process. ### Claim 48 (depends on 47) The inkjet printing apparatus according to claim 47, wherein the first path is for supplying liquid from the liquid storage unit to the printing unit, and wherein the second path is for collecting liquid from the printing unit to the liquid storage unit. ### Claim 49 (depends on 46) The inkjet printing apparatus according to claim 46, comprising a conveyance unit configured to convey the print medium in first direction, wherein the multiple ejection openings are arrayed in a direction intersecting the first direction by a length corresponding to a width of the print medium. ### Claim 50 (depends on 46) The inkjet printing apparatus according to claim 46, wherein the printing unit includes a printing element configured to eject liquid from the ejection opening in performing the printing process, and the discharge unit is different from the printing element. ### Claim 51 (depends on 50) The inkjet printing apparatus according to claim 50, wherein the discharge unit is a unit provided outside a print head. ### Claim 52 (depends on 46) The inkjet printing apparatus according to claim 46, the discharge process is from a start to an end of a liquid discharge from the multiple ejection openings. ### Claim 53 (depends on 46) The inkjet printing apparatus according to claim 46, the discharge unit performs the discharge process by causing the multiple ejection openings to discharge liquid sequentially while moving relative to the printing unit. ### Claim 54 (depends on 46) The inkjet printing apparatus according to claim 46, wherein during the discharge process, the printing unit performs preliminary ejection from at least the ejection openings for which the discharge by the discharge unit has been finished while the discharge unit discharges liquid from the ejection openings for which the discharge by the discharge unit has not been finished. ### Claim 55 A recovery method comprising: moving at least one of a discharge unit and a printing unit relatively with respect to the other, the printing unit including arrayed multiple ejection openings configured to perform a printing process for ejecting liquid according to print data, the discharge unit being at a position facing an ejection opening surface of the printing unit, on which surface the ejection openings are formed, multiple flow paths having a first path for flowing the liquid from the outside of the printing unit to the inside of the printing unit and a second path for flowing the liquid from the inside of the printing unit to the outside of the printing unit; and discharging liquid from the ejection openings in order with the discharge unit, wherein the discharging liquid is different from the printing process, wherein while the discharge is performed for the ejection openings with the discharge unit, liquid is circulated in at least one of the flow paths. ### Claim 56 (depends on 55) The recovery method according to claim 55, wherein the flow path is a flow path for a liquid in which the degree of increase in viscosity due to evaporation of a liquid component in the liquid under a specified condition is higher than or equal to a specified degree. ### Claim 57 A recovery method comprising: moving at least one of a discharge unit and a printing unit relatively with respect to the other, the printing unit including arrayed multiple ejection openings and being configured to perform a printing process for ejecting liquid according to print data, the discharge unit being at a position facing an ejection opening surface of the printing unit, on which the ejection openings are formed, multiple flow paths having a first path for flowing the liquid from the outside of the printing unit to the inside of the printing unit and a second path for flowing the liquid from the inside of the printing unit to the outside of the printing unit; and discharging liquid from the ejection openings in order with the discharge unit, wherein the discharging liquid is different from the printing process, wherein while the discharge is performed for the ejection openings with the discharge unit, preliminary ejection, which is liquid ejection different from ejection of the printing process is performed from the printing unit.