Inkjet printing apparatus and inkjet printing method
An inkjet printing apparatus has a print head ejecting ink from an ejection opening. A printing element generates energy for ejecting the ink. A printing element substrate mounts a printing element, the ejection opening, and the pressure chamber. A decision unit performs a decision operation for deciding an ink ejection state of the ejection opening. A circulation unit performs a circulation operation to circulate ink from outside the pressure chamber to the inside and from the inside to the outside by causing ink to flow from a first flow path for supplying ink to the pressure chamber to a second flow path, and to circulate the ink so that ink that has flowed through the second flow path flows through the first again. A control unit causes the circulation unit to perform the circulation operation and the decision unit to perform the decision operation at the same time.
1 . An inkjet printing apparatus comprising:
a print head comprising at least one ejection opening for ejecting ink, a printing element for generating energy used for ejecting ink corresponding to the ejection opening, a pressure chamber that is an area facing to the printing element, and a printing element substrate on which the printing element, the ejection opening, and the pressure chamber are provided, the ejection opening ejecting ink supplied in the pressure chamber;
a decision unit configured to perform a decision operation for deciding an ink ejection state of the ejection opening;
a circulation unit provided outside of the printing element substrate and configured to perform a circulation operation in which ink is circulated from outside of the pressure chamber to the inside of the pressure chamber and from the inside of the pressure chamber to the outside of the pressure chamber by supplying ink such that the ink flows from a first flow path for supplying ink to the pressure chamber to a second flow path, and further configured to circulate the ink so that ink that has flowed through the second flow path communicating with the pressure chamber and being different from the ejection opening and the first flow path, wherein no circulation unit configured to perform the circulation operation is provided on the printing element substrate; and
a control unit configured to cause the circulation unit to perform the circulation operation and to cause the decision unit to perform the decision operation, the circulation operation and the decision operation being performed at the same time.
2 . The inkjet printing apparatus according to claim 1 , wherein the print head further comprises a plurality of ejection openings including the at least one ejection opening, and,
based on a decision result of the decision unit, the control unit causes the decision unit to continue the decision operation in a case when a number of inoperative ejection openings is greater than a first number and causes the decision unit to finish the decision operation in a case when the number of inoperative ejection openings is not greater than the first number.
3 . The inkjet printing apparatus according to claim 2 , wherein, based on the decision result of the decision unit, the control unit further causes the circulation unit to continue the ink circulation in a case when the number of inoperative ejection openings is greater than the first number and causes the circulation unit to stop the ink circulation in a case when the number of inoperative ejection openings is not greater than the first number.
4 . The inkjet printing apparatus according to claim 2 , wherein
the control unit prevents the circulation unit from stopping the ink circulation until the decision unit finishes the decision operation.
5 . The inkjet printing apparatus according to claim 2 , wherein, in a case when the number of inoperative ejection openings is not greater than the first number,
in a case when a next operation to be performed by the inkjet printing apparatus is not accompanied by the ink circulation, the control unit causes the circulation unit to stop the ink circulation, and,
in a case when the next operation is accompanied by the ink circulation, the control unit prevents the circulation unit from stopping the ink circulation.
6 . The inkjet printing apparatus according to claim 5 , wherein
the next operation includes an operation of printing an image by using ink ejected from the print head.
7 . The inkjet printing apparatus according to claim 2 , wherein, in a case when the number of inoperative ejection openings is greater than the first number, the control unit performs the decision operation after a lapse of a first predetermined time and prevents the circulation unit from stopping the ink circulation until the decision unit finishes the decision operation.
8 . The inkjet printing apparatus according to claim 2 , wherein the control unit causes the decision unit to finish the decision operation in a case when the number of inoperative ejection openings is not reduced to the first number or fewer within a second predetermined time from a start of the decision operation.
9 . The inkjet printing apparatus according to claim 2 , wherein the control unit causes the decision unit to perform the decision operation multiple times and, in a case when a determination unit determines multiple times that the number of inoperative ejection openings is equal to or fewer than a predetermined number, causes the decision unit to finish the decision operation.
10 . The inkjet printing apparatus according to claim 1 , further comprising a cap capable of intimately contacting with the ejection opening of the print head, wherein the control unit causes the circulation unit to circulate ink with the ejection opening in intimate contact with the cap into which ink is ejected from the ejection opening.
11 . The inkjet printing apparatus according to claim 1 , wherein the print head is capable of ejecting a plurality of inks,
the control unit causes the circulation unit to circulate the ink through a flow path for each of the plurality of inks, and
the decision unit performs the decision operation for a specific ink out of the plurality of inks.
12 . The inkjet printing apparatus according to claim 11 , wherein the plurality of inks include inks having different thickening properties, which are degrees of thickening caused by moisture evaporation from the ink, and the specific ink is an ink having a relatively high thickening property.
13 . The inkjet printing apparatus according to claim 1 , wherein the decision unit decides the ink ejection state in the print head based on a temperature change in the electrothermal transducing element in a case when the ink is ejected from the ejection opening, the temperature change being decided by the temperature decision element.
14 . The inkjet printing apparatus according to claim 1 , wherein the print head is capable of ejecting the ink from the plurality of ejection openings,
the circulation unit circulates the ink through each of flow paths of the plurality of ejection openings, and p 1 the control unit causes the circulation unit to perform the ink circulation and performs the decision operation for an ejection opening selected from the plurality of ejection openings.
15 . The inkjet printing apparatus according to claim 1 , wherein
the printing element is an electrothermal transducing element, and
the decision unit comprises a temperature decision element configured to decide a temperature of the electrothermal transducing element.
16 . The inkjet printing apparatus according to claim 1 , wherein the control unit causes the decision unit to perform the decision operation in response to a start of the ink circulation by the circulation unit.
17 . The inkjet printing apparatus according to claim 1 , further comprising:
a tank configured to store the ink to be supplied to the print head;
a third flow path configured to cause the ink to flow from the tank to the first flow path of the print head; and
a fourth flow path configured to cause the ink to flow from the second flow path of the print head to the tank,
wherein the circulation unit circulates the ink between the tank and the print head such that the ink flows from the tank to the pressure chamber and from the pressure chamber to the tank.
18 . The inkjet printing apparatus according to claim 1 , wherein
the decision unit comprises a decision element provided corresponding to the printing element in the print head.
19 . The inkjet printing apparatus according to claim 1 , wherein the control unit causes the circulation unit to stop circulating the ink from outside of the pressure chamber to the inside of the pressure chamber and from the inside of the pressure chamber to the outside of the pressure chamber, in response to completion of the decision operation.
20 . The inkjet printing apparatus according to claim 1 , further comprising:
a third flow path configured to cause the ink to flow from a tank that is configured to store ink to be supplied to the first flow path of the print head; and
a fifth flow path whose one end is connected to the third flow path and which that is configured to return a portion of the ink in the third flow path to a position in the third flow path upstream from a connecting portion of the one end.
21 . The inkjet printing apparatus according to claim 20 , further comprising a valve located in the fifth flow path.
22 . The inkjet printing apparatus according to claim 21 , wherein the one end of the fifth flow path and its other end are both connected to the third flow path.
23 . The inkjet printing apparatus according to claim 21 , wherein the valve is configured, in a case when the pressure of the pumped ink in the third flow path is greater than a predetermined value, to open the fifth flow path so as to allow ink in the fifth flow path to flow from a downstream side of the third flow path to an upstream side of the third flow path.
24 . The inkjet printing apparatus according to claim 20 , further comprising a pressure control unit located in a flow path between the fifth flow path and the pressure chamber, and configured to open the flow path so as to cause the ink to flow from the first flow path to the pressure chamber caused by a negative pressure.
25 . The inkjet printing apparatus according to claim 24 , wherein the inkjet printing apparatus comprises two of the pressure control units.
26 . The inkjet printing apparatus according to claim 1 , wherein the control unit is further configured to cause the decision unit to perform the decision operation in a period of the circulation unit circulating the ink.
27 . The inkjet printing apparatus according to claim 1 , further comprising a main tank configured to store ink to be supplied to the print head and located above the print head in the vertical direction.
28 . The inkjet printing apparatus according to claim 1 , further comprising:
a tank configured to store ink to be supplied to the print head; and
a main tank configured to store the ink to be supplied to the tank and located above the print head in the vertical direction.
29 . The inkjet printing apparatus according to claim 1 , further comprising a third flow path configured to flow ink from the tank to the first flow path of the print head, wherein the circulation unit is provided in the third flow path.
30 . The inkjet printing apparatus according to claim 1 , further comprising:
a tank configured to store ink to be supplied to the print head;
a third flow path configured to cause the ink to flow from the tank to the first flow path of the print head; and
a fourth flow path configured to cause the ink to flow so that ink that has flowed through the first flow path and through the second flow path flows through the first flow path again,
wherein the circulation unit circulates the ink in a circulation path including the first flow path and the second flow path so that the ink that has flowed through the second flow path flows through the first flow path again.
31 . An inkjet printing apparatus comprising:
a print head comprising at least one ejection opening for ejecting ink;
a tank configured to store ink to be supplied to the print head;
a first flow path configured to cause ink to flow from the tank to the print head;
a second flow path configured to cause ink that has flowed through the first flow path and through the second flow path to flow through the first flow path again;
a decision unit configured to perform a decision operation for deciding an ink ejection state of the ejection opening;
a circulation unit provided in the first flow path and configured to circulate the ink in a circulation path including the first flow path and the second flow path, so that ink that has flowed through the second flow path flows through the first flow path again; and
a control unit configured to cause the circulation unit to perform a circulation operation in which the ink is circulated and to cause the decision unit to perform the decision operation, the circulation operation and the decision operation being performed at the same time.
32 . The inkjet printing apparatus according to claim 31 , wherein the print head further comprises a plurality of ejection openings including the at least one ejection opening, and,
based on a decision result of the decision unit, the control unit causes the decision unit to continue the decision operation in a case where when a number of inoperative ejection openings is greater than a first number and causes the decision unit to finish the decision operation in a case where when the number of inoperative ejection openings is not greater than the first number.
33 . The inkjet printing apparatus according to claim 32 , wherein, based on the decision result of the decision unit, the control unit causes the circulation unit to continue the ink circulation in a case when the number of inoperative ejection openings is greater than the first number and causes the circulation unit to stop the ink circulation in a case when the number of inoperative ejection openings is not greater than the first number.
34 . The inkjet printing apparatus according to claim 32 , wherein
the control unit prevents the circulation unit from stopping the ink circulation until the decision unit finishes the decision operation.
35 . The inkjet printing apparatus according to claim 32 , wherein, in a case when the number of inoperative ejection openings is not greater than the first number.
36 . The inkjet printing apparatus according to claim 31 , wherein the control unit causes the decision unit to perform the decision operation in response to a start of ink circulation by the circulation unit.
37 . The inkjet printing apparatus according to claim 31 , wherein the control unit causes the circulation unit to stop circulating the ink from outside of the pressure chamber to the inside of the pressure chamber and from the inside of the pressure chamber to the outside of the pressure chamber, in response to completion of the decision operation.
38 . The inkjet printing apparatus according to claim 31 , further comprising
a third flow path configured to cause ink to flow from a tank that is configured to store ink to be supplied to the first flow path of the print head; and
a fifth flow path whose one end is connected to the third flow path, whose other end is connected to the third flow path at a position upstream from the one end and that is configured to return a portion of the ink in the third flow path from the one end to the other end.
39 . The inkjet printing apparatus according to claim 38 , further comprising a valve located in the fifth flow path.
40 . The inkjet printing apparatus according to claim 39 , wherein the one end of the fifth flow path and its other end are both connected to the third flow path.
41 . The inkjet printing apparatus according to claim 39 , wherein the valve is configured, in a case when the pressure of the pumped ink in the third flow path is greater than a predetermined value, to open the fifth flow path so as to allow the ink in the fifth flow path to flow from a downstream side of the third flow path to an upstream side of the third flow path.
42 . The inkjet printing apparatus according to claim 38 , further comprising a pressure control unit located in a flow path between the fifth flow path and the pressure chamber, and configured to open the flow path so as to cause ink to flow from the first flow path to the pressure chamber caused by a negative pressure.
43 . The inkjet printing apparatus according to claim 42 , wherein the inkjet printing apparatus comprises two of the pressure control units.
44 . An inkjet printing method comprising:
a circulation step of circulating ink in a print head, the print head comprising at least one ejection opening for ejecting ink, a printing element for generating energy used for ejecting ink corresponding to the ejection opening, a pressure chamber that is an area facing the printing element, and a printing element substrate on which the printing element, the ejection opening, and the pressure chamber are provided;
ejecting ink supplied in the pressure chamber through the ejection opening;
circulating the ink by circulating the ink from outside of the pressure chamber to the inside of the pressure chamber and from the inside of the pressure chamber to the outside of the pressure chamber by supplying ink such that the ink flows from a first flow path for supplying ink to the pressure chamber of the print head to a second flow path, so that ink that has flowed through the second flow path flows through the first flow path again, the second flow path communicating with the pressure chamber and being different from the ejection opening and the first flow path; and
deciding an ink ejection state of the ejection opening,
wherein the circulating of the ink and the deciding the ink ejection state are performed at the same time.
45 . The inkjet printing method according to claim 44 , wherein the deciding of the ink ejection state is performed in response to a start of ink circulation in the circulation step.
46 . The inkjet printing method according to claim 44 , wherein the circulating of the ink is prevented from stopping until the deciding of the ink ejection state is finished.
47 . The inkjet printing method according to claim 44 , wherein the circulating of the ink is stopped in response to finishing of the deciding of the ink ejection state.
48 . A non-transitory computer readable storage medium storing a program for causing a computer to function as an inkjet printing apparatus, the inkjet printing apparatus comprising:
a print head comprising at least one ejection opening for ejecting ink, a printing element for generating energy used for ejecting ink corresponding to the ejection opening, a pressure chamber that is an area facing the printing element, and a printing element substrate on which the printing element, the ejection opening, and the pressure chamber are provided, the ejection opening ejecting ink supplied in the pressure chamber;
a decision unit configured to perform a decision operation for deciding an ink ejection state of the ejection opening;
a circulation unit provided outside of the printing element substrate and configured to perform a circulation operation in which ink is circulated from outside of the pressure chamber to the inside of the pressure chamber and from the inside of the pressure chamber to the outside of the pressure chamber by supplying the ink such that the ink flows from a first flow path for supplying the ink to the pressure chamber of the print head to a second flow path, and further configured to circulate the ink so that ink that has flowed through the second flow path flows through the first flow path again, the second flow path communicating with the pressure chamber and being different from the ejection opening and the first flow path, wherein no circulation unit configured to perform the circulation operation is provided on the printing element substrate; and
a control unit configured to cause the circulation unit to perform the circulation operation and to cause the decision unit to perform the decision operation, the circulation operation and the decision operation being performed at the same time.
49 . A non-transitory computer readable storage medium storing a program for causing a computer to function as an inkjet printing apparatus, the inkjet printing apparatus comprising:
a print head comprising at least one ejection opening for ejecting ink;
a tank configured to store ink to be supplied to the print head;
a first flow path configured to cause ink to flow from the tank to the print head;
a second flow path configured to cause ink to flow so that ink that has flowed through the first flow path and through the second flow path flows through the first flow path again;
a decision unit configured to perform a decision operation for deciding an ink ejection state of the ejection opening;
a circulation unit provided in the first flow path and configured to circulate the ink in a circulation path including the first flow path and the second flow path so that ink that has flowed through the second flow path flows through the first flow path again; and
a control unit configured to cause the circulation unit to perform a circulation operation in which ink is circulated and to cause the decision unit to perform the decision operation, the circulation operation and the decision operation being performed at the same time.
50 . The inkjet printing apparatus according to claim 1 , wherein the print head itself has no driving source for causing ink to flow, and the circulation unit is provided outside of the print head.
51 . The inkjet printing method according to claim 44 . . . . . . circulation unit is provided on the printing element substrate.