JP2023142248A - Inkjet recording apparatus - Google Patents

Abstract

To provide an inkjet recording apparatus capable of suppressing movement of air bubbles in an ink channel to a recording head when recording on a recording medium.SOLUTION: An inkjet recording apparatus 1 comprises a recording head 52, an ink container 81, a sub-tank 83, a feed pump 84, a circulation pump 85, a syringe 86, a first channel 87, and a control part. Ink is flowed into the syringe 86 from the feed pump 84 and flowed out toward the recording head 52, and the syringe can apply to the ink a maintenance pressure higher than a recording pressure applied by the feed pump 84. The control part, when no image is recorded, can execute a forced circulation mode in which the ink is forcefully circulated toward the downstream side in an ink circulation direction of the syringe 86 by applying the maintenance pressure to the ink with the syringe 86.SELECTED DRAWING: Figure 4

Description

The present invention relates to an inkjet recording device.

An inkjet recording apparatus includes a recording head that records an image by ejecting ink onto a recording medium such as paper. In an inkjet recording device, if bubbles are generated in a nozzle that discharges ink onto a recording medium, the discharge performance may be affected, and problems such as deflection of ink flight or non-discharge may occur, leading to image defects. Therefore, in the inkjet recording apparatus, it is necessary to suppress the generation of bubbles in the recording head and the ink flow path.

The conventional liquid circulation device disclosed in Patent Document 1 has a circulation path in which liquid circulates through a liquid ejection head. This circulation path includes a manifold that communicates with each of the supply ports of the plurality of liquid ejection heads, and a pressurized subtank that communicates with the manifold and is pressurized inside. The pressurized sub-tank is arranged at a position higher than the position where the supply port of the liquid ejection head is arranged. Thereby, when using a circulating head, the nozzle meniscus pressure can be appropriately set, and liquid dripping from the nozzle and air bubble entrainment can be reduced.

Unexamined Japanese Patent Publication No. 2019-1000

However, in an inkjet recording apparatus, when ink is circulated as in the prior art, air bubbles may stay at the joints of the ink channels or adhere to the walls within the channels. The problem is that the flow rate of the ink during circulation is not sufficient to intentionally move the air bubbles in the ink flow path away from the print head, and the air bubbles move to the print head when printing on the print medium, causing image defects. there were.

The present invention has been made in view of the above points, and it is an object of the present invention to provide an inkjet recording device that can suppress air bubbles in an ink flow path from moving to a recording head during recording on a recording medium. purpose.

In order to solve the above problems, an inkjet recording apparatus of the present invention includes a recording head, an ink container, a sub tank, a supply pump, a circulation pump, a syringe, a first flow path, and a control section. . The recording head has a plurality of nozzles that eject ink onto a recording medium. The ink container accommodates the ink to be supplied to the recording head. The sub-tank temporarily stores the ink supplied from the ink container. The supply pump supplies the ink from the sub tank to the recording head. The circulation pump circulates the ink from the recording head to the sub tank. The syringe is capable of applying a maintenance pressure to the ink that is higher than the recording pressure applied by the supply pump as the ink flows in from the supply pump and flows out toward the recording head. In the first flow path, the ink circulates from the sub-tank to the sub-tank via the supply pump, the syringe, the recording head, and the circulation pump. The control unit controls operations of the recording head, the supply pump, the circulation pump, and the syringe, and records an image on the recording medium. The control unit is capable of executing a forced circulation mode in which the maintenance pressure is applied to the ink by the syringe to forcibly flow the ink toward the downstream side of the syringe in the ink circulation direction during non-image recording.

According to the configuration of the present invention, when an image is not recorded, the bubbles in the first flow path can be moved and moved away from the recording head. That is, it is possible to suppress air bubbles in the ink flow path from moving to the recording head during recording on a recording medium.

1 is a schematic cross-sectional front view of an inkjet recording apparatus according to an embodiment of the present invention. FIG. 2 is a plan view of the vicinity of a recording section of the inkjet recording apparatus of FIG. 1. FIG. 2 is a block diagram showing a schematic configuration of the inkjet recording apparatus shown in FIG. 1. FIG. FIG. 2 is an explanatory diagram showing the configuration of an ink supply section of the inkjet recording apparatus of FIG. 1. FIG. 5 is a cross-sectional view of the syringe of the ink supply section of FIG. 4. FIG. FIG. 5 is an explanatory diagram of an on-off valve of the ink supply section in FIG. 4; FIG. 5 is a cross-sectional view of the damper of the ink supply section of FIG. 4;

Embodiments of the present invention will be described below based on the drawings. Note that the present invention is not limited to the following content.

FIG. 1 is a schematic cross-sectional front view of an inkjet recording apparatus 1 according to an embodiment. FIG. 2 is a plan view of the vicinity of the recording section 5 of the inkjet recording apparatus 1 of FIG. 1. FIG. 3 is a block diagram showing a schematic configuration of the inkjet recording apparatus 1 of FIG. 1. As shown in FIG. The inkjet recording device 1 is, for example, an inkjet recording printer. As shown in FIGS. 1, 2, and 3, the inkjet recording apparatus 1 includes an apparatus main body 2, a paper supply section 3, a paper transport section 4, a recording section 5, a drying section 6, and a control section 7. , is provided.

The paper supply section 3 is arranged, for example, at the bottom of the apparatus main body 2. The paper supply section 3 stores a plurality of sheets of paper (recording medium) S, and separates and sends out the sheets S one by one during recording.

The paper transport section 4 is disposed downstream of the paper supply section 3 in the paper transport direction, and transports the paper S sent out from the paper supply section 3. The paper transport unit 4 transports the paper S to the recording unit 5 and the drying unit 6, and further discharges the recorded and dried paper S to the paper discharge unit 21. The paper conveyance section 4 includes, for example, a reversal conveyance section 4r. When double-sided recording is performed, the paper transport unit 4 distributes the paper S after recording and drying the first side to the reversing transport unit 4r, and then switches the transport direction and transfers the paper S, which has been reversed from front to back, to the recording unit again. 5 and the drying section 6.

The paper transport section 4 includes a first belt transport section 41 and a second belt transport section 42 . The first belt conveyance section 41 has a first conveyance belt 411 formed in an endless shape. The second belt conveyance section 42 has a second conveyance belt 421 formed in an endless shape. The first belt transport section 41 and the second belt transport section 42 transport the paper S by suctioning and holding it on the upper outer surface (upper surface) of the first transport belt 411 and the second transport belt 421, respectively. The first belt conveyance section 41 is arranged below the recording section 5 and conveys the paper S. The second belt transport section 42 is located downstream of the first belt transport section 41 in the paper transport direction, is disposed in the drying section 6, and transports the paper S.

The recording section 5 is located on the downstream side of the paper supply section 3 in the paper conveyance direction, and is arranged to face the first belt conveyance section 41 . The recording unit 5 is disposed above the first conveyor belt 411 with a predetermined interval therebetween, facing the sheet S that is being conveyed while being attracted to the upper surface of the first conveyor belt 411 . That is, the recording unit 5 faces the paper S transported by the paper transport unit 4.

As shown in FIG. 2, the recording section 5 holds head units 51B, 51C, 51M, and 51Y corresponding to each of four colors: black, cyan, magenta, and yellow. The head units 51B, 51C, 51M, and 51Y are arranged side by side along the paper conveyance direction Dc so that their longitudinal directions are parallel to the paper width direction Dw that is perpendicular to the paper conveyance direction Dc. Note that the four head units 51B, 51C, 51M, and 51Y have the same basic configuration, so in the following description, unless otherwise specified, "B", "C", and "C" representing each color will be used. The identification symbols "M" and "Y" may be omitted.

Each of the head units 51 for each color has a recording head 52 of a line type inkjet system. A plurality of recording heads 52 (for example, three (52a, 52b, 52c)) are arranged in a staggered manner along the paper width direction Dw in each of the head units 51 of each color.

The recording head 52 has a plurality of ink ejection nozzles 521 at its bottom. The plurality of ink ejection nozzles 521 are arranged side by side along the paper width direction Dw, and can eject ink over the entire recording area on the paper S. That is, the recording head 52 has a plurality of ink ejection nozzles 521 that eject ink onto the paper S. The recording unit 5 sequentially discharges ink from the recording heads 52 of the four color head units 51B, 51C, 51M, and 51Y toward the paper S conveyed by the first conveyor belt 411, and prints a full-color image or a monochrome image on the paper. Record in S.

The drying section 6 is arranged on the downstream side of the recording section 5 in the paper conveyance direction, and is provided with a second belt conveyance section 42 . The ink is dried on the paper S on which the ink image has been recorded in the recording section 5 while being conveyed while being sucked and held by the second conveyance belt 421 in the drying section 6 .

The control unit 7 includes a CPU, a storage unit, and other electronic circuits and electronic components (all not shown). The CPU controls the operation of each component provided in the inkjet recording apparatus 1 based on control programs and data stored in the storage unit, and performs processing related to the functions of the inkjet recording apparatus 1. The paper supply section 3, the paper transport section 4, the recording section 5, and the drying section 6 each receive instructions from the control section 7 individually, and perform recording on the paper S in conjunction with each other. The storage unit is configured by a combination of a non-volatile storage device such as a program ROM (Read Only Memory) and a data ROM, and a volatile storage device such as a RAM (Random Access Memory).

Next, the configuration of the ink supply section 8 of the inkjet recording apparatus 1 will be explained using FIGS. 4 to 7. FIG. 4 is an explanatory diagram showing the configuration of the ink supply section 8 of the inkjet recording apparatus 1 of FIG. 1. FIG. 5 is a cross-sectional view of the syringe of the ink supply section 8 of FIG. 4. FIG. 6 is an explanatory diagram of the on-off valve of the ink supply section 8 of FIG. 4. FIG. 7 is a sectional view of the damper of the ink supply section 8 of FIG. 4.

The inkjet recording apparatus 1 includes an ink supply section 8. The ink supply section 8 is provided individually for each of the four color head units 51. In the following description, identification symbols representing each color will be omitted. The ink supply section 8 and the head unit 51 are connected by a detachable coupling 11. A valve member (not shown) that opens the ink flow path in the connected state and closes the ink flow path in the separated state is built into the coupling 11.

The ink supply unit 8 includes an ink container 81 , a container pump 82 , a sub-tank 83 , a supply pump 84 , a circulation pump 85 , a syringe 86 , and a first channel 87 .

The ink container 81 is removably installed in the apparatus main body 2 . The ink container 81 accommodates ink to be supplied to the recording head 52.

The container pump 82 is arranged on the downstream side of the ink container 81 in the ink flow direction. The container pump 82 sucks ink in the ink container 81 and discharges it toward the sub-tank 83. The operation of the container pump 82 is controlled by the control section 7.

The sub tank 83 is arranged downstream of the container pump 82 in the ink flow direction. The sub tank 83 temporarily stores ink supplied from the ink container 81. The sub tank 83 is provided with an ink amount sensor (not shown). The ink amount sensor includes, for example, an optical type sensor, a capacitance type sensor, an electrode type sensor, a differential pressure type sensor, a float type sensor, and detects the amount of ink in the sub tank 83.

The control unit 7 receives a detection signal from the ink amount sensor. When the amount of ink in the sub-tank 83 detected by the ink amount sensor becomes lower than a predetermined value, the control unit 7 controls the container pump 82 to supply ink from the ink container 81 to the sub-tank 83. The amount of ink supplied from the ink container 81 to the sub-tank 83 is controlled, for example, by the driving time of the container pump 82. If the amount of ink in the sub-tank 83 detected by the ink amount sensor does not become higher than a predetermined value even after the driving time of the container pump 82 has passed for a certain period of time, the control unit 7 determines that the amount of ink in the ink container 81 is empty. It is determined that there is.

The supply pump 84 is arranged downstream of the sub-tank 83 in the ink flow direction. The supply pump 84 supplies ink from the sub-tank 83 to the recording head 52 . The supply pump 84 can be selected from liquid pumps such as tube pumps and diaphragm pumps. The operation of the supply pump 84 is controlled by the control section 7.

The circulation pump 85 is arranged downstream of the recording head 52 in the ink flow direction. The circulation pump 85 circulates ink from the recording head 52 to the sub tank 83. The circulation pump 85 can be selected from liquid pumps such as tube pumps and diaphragm pumps. The operation of the circulation pump 85 is controlled by the control unit 7.

Regarding the supply of ink to the recording head 52 and the circulation of ink, a first flow path 87, which will be described later, is provided with pressure sensors S1 and S2 that detect the pressure applied to the ink. The pressure sensor S1 is arranged on the upstream side of the recording head 52 in the ink flow direction. The pressure sensor S2 is arranged on the downstream side of the recording head 52 in the ink flow direction. The control unit 7 controls the operations of the supply pump 84 and the circulation pump 85 in real time in an analog manner based on the detection signals of the pressure sensors S1 and S2.

The syringe 86 is disposed downstream of the supply pump 84 in the ink flow direction and upstream of the recording head 52 in the ink flow direction. Ink flows into the syringe 86 from the supply pump 84 and flows out toward the recording head 52 . As shown in FIG. 5, the syringe 86 includes a cylindrical portion 861 and a plunger 862.

The cylindrical portion 861 has a cylindrical shape and is arranged so that its axis extends in the vertical direction. The upper end of the cylindrical portion 861 is open. The lower end of the cylindrical portion 861 is closed, and a first conduit 871 extending from the supply pump 84 side and a second conduit 872 extending toward the recording head 52 of a first flow path 87 to be described later are connected. The first conduit 871 and the second conduit 872 communicate with the inside of the cylindrical portion 861.

The plunger 862 is inserted into the inside of the cylindrical portion 861 from the upper end opening of the cylindrical portion 861 . Plunger 862 has a shaft portion 862a and a gasket portion 862b. The shaft portion 862a is formed so that its axis extends in the vertical direction. Gasket portion 862b is arranged at the lower end of shaft portion 862a. The gasket portion 862b has a cylindrical shape extending along the inner circumferential surface of the cylindrical portion 861, and its outer circumferential surface is in close contact with the inner circumferential surface of the cylindrical portion 861. Thereby, the ink within the cylinder portion 861 does not leak above the gasket portion 862b.

A fourth conduit 941 of a second flow path 94, which will be described later, is inserted into the radial center of the plunger 862. The fourth conduit 941 communicates with the inside of the cylindrical portion 861. Air remaining within the cylinder portion 861, that is, above the ink within the syringe 86 and below the gasket portion 862b, is discharged upward via the fourth conduit 941. Note that the second flow path 94 extends to the sub-tank 83.

A rack 862c is formed on the side surface of the shaft portion 862a. The rack 862c has a plurality of teeth arranged in parallel along the vertical direction, and the syringe drive gear 863 meshes with the rack 862c. The syringe drive gear 863 is connected to a syringe motor 864 (see FIG. 3), receives power from the syringe motor 864, and is rotated in both forward and reverse directions. By rotating the syringe drive gear 863 in both forward and reverse directions, the plunger 862 can reciprocate along the up and down direction. The operation of the syringe motor 864 is controlled by the control section 7.

When recording an image on the paper S, recording pressure is applied to the ink by the supply pump 84. On the other hand, during maintenance, for example, the control unit 7 applies a maintenance pressure higher than the recording pressure to the ink by moving the plunger 862 downward at high speed using the syringe motor 864 and pushing out the ink from within the syringe 86. be able to. That is, the syringe 86 is capable of applying a higher maintenance pressure to the ink than the recording pressure applied by the supply pump 84.

The first flow path 87 is an ink flow path through which ink circulates from the sub-tank 83 to the sub-tank 83 via the supply pump 84, the syringe 86, the recording head 52, and the circulation pump 85. The first flow path 87 includes a first conduit 871 extending from the supply pump 84 to the syringe 86, a second conduit 872 extending from the syringe 86 to the recording head 52, and a third conduit 873 extending from the recording head 52 to the circulation pump 85. including. Check valves CV1 and CV2 are arranged on the first conduit 871 and the third conduit 873. The check valves CV1 and CV2 prevent ink from flowing backward from the downstream side to the upstream side with respect to the ink flow direction of the first flow path 87.

The control unit 7 can execute a forced distribution mode in which maintenance pressure is applied to the ink by the syringe 86 and the ink is forced to flow toward the downstream side of the syringe 86 in the ink distribution direction during non-image recording. This allows the bubbles in the first flow path 87, which is an ink flow path, to be moved and away from the recording head 52 during non-image recording. That is, when recording on the paper S, it is possible to suppress air bubbles in the first flow path 87 from moving to the recording head 52.

Furthermore, the control unit 7 can execute a cleaning mode in which the recording head 52 is cleaned by forcibly expelling ink from the ink ejection nozzles 521 during non-image recording. In the cleaning mode, ink is ejected from the ink ejection nozzle 521 onto the ink ejection surface (not shown) of the recording head 52 . The ejected ink contains, for example, highly viscous ink inside the ink ejection nozzle 521, foreign matter, and the like, and is held below the ink ejection surface by surface tension. Thereafter, the ink on the ink ejection surface is wiped off by a wiper (not shown) or the like.

Then, the control unit 7 executes the forced circulation mode when executing the cleaning mode. As a result, when the cleaning mode is executed, the bubbles in the first flow path 87, which is an ink flow path, can be moved away from the recording head 52 or ejected from the ink ejection nozzle 521. By using a constant volume syringe 86 for forced ejection of ink from the ink ejection nozzle 521, it is possible to suppress the amount of ink consumption to a minimum. Note that when ink is forcibly ejected from the ink ejection nozzle 521, the forced circulation mode can be executed regardless of the operating states of the supply pump 84 and the circulation pump 85.

Further, the ink supply section 8 includes a first on-off valve 91, a second on-off valve 92, a damper 93, a second channel 94, a third on-off valve 95, a third channel 96, and a relief valve 97. , a fourth flow path 98 , and an opening/closing mechanism 99 .

The first on-off valve 91 is arranged on the first conduit 871 of the first flow path 87 on the downstream side of the check valve CV1 in the ink flow direction. Note that the first conduit 871 is a tube made of rubber, for example, and can be deformed by bending or bending. As shown in FIG. 6, the first on-off valve 91 includes an on-off cam 91a and an on-off motor (not shown).

The opening/closing cam 91a is adjacent to the first conduit 871. The opening/closing cam 91a is formed into a wedge shape when viewed from the axial direction of the first conduit 871. The opening/closing cam 91a is rotatably supported about a rotation axis parallel to the axis of the first conduit 871. The opening/closing cam 91a is rotated and swung by the opening/closing motor, and the wedge-shaped tip side comes into contact with and separates from the first conduit 871.

When the first on-off valve 91 is in the open state, the control unit 7 controls the on-off motor to rotate the on-off cam 91a so that the on-off cam 91a does not come into contact with the first conduit 871 or the first conduit 871 is not deformed. Make it an angle. As a result, ink flows through the first conduit 871 at the first on-off valve 91 . When the first on-off valve 91 is in the closed state, the control unit 7 controls the on-off motor to rotate the on-off cam 91a, brings the on-off cam 91a into contact with the first conduit 871, and angles to crush the first conduit 871. Make it. This prevents the flow of ink within the first conduit 871 at the first on-off valve 91 .

The first on-off valve 91 opens and closes the first flow path 87 between the supply pump 84 and the syringe 86 . The first on-off valve 91 is composed of, for example, a solenoid valve, and its opening and closing are controlled by the control unit 7 .

The second on-off valve 92 is arranged on the second conduit 872 of the first flow path 87. The configuration and operation of the second on-off valve 92 are the same as those of the first on-off valve 91 described above, and the description thereof will be omitted here. The second on-off valve 92 opens and closes the first flow path 87 between the syringe 86 and the recording head 52. The second on-off valve 92 is composed of, for example, a solenoid valve, and its opening and closing are controlled by the control unit 7.

Then, the control unit 7 closes the first on-off valve 91 and opens the second on-off valve 92 when executing the forced circulation mode. Thereby, when the forced circulation mode is executed, ink on the upstream side in the ink circulation direction with respect to the recording head 52 can be pushed out toward the recording head 52. Therefore, it is possible to enhance the effect of moving the bubbles in the first flow path 87 and moving them away from the recording head 52.

The damper 93 is arranged between the supply pump 84 and the syringe 86 and between the recording head 52 and the circulation pump 85, respectively. Specifically, the first damper 93 is disposed on the first conduit 871 of the first flow path 87, downstream of the supply pump 84 in the ink flow direction and upstream of the check valve CV1 in the ink flow direction. be done. More specifically, the second damper 93 is located on the third conduit 873 of the first flow path 87, downstream of the check valve CV2 in the ink flow direction and upstream of the circulation pump 85 in the ink flow direction. Placed.

The damper 93 has a damper chamber 931 and a film 932, as shown in FIG. The damper chamber 931 has a gap that is convex upward relative to the first channel 87 through which ink flows, for example, in a horizontal direction. A lower wall portion of the first flow path 87 that faces the damper chamber 931 in the vertical direction is open. The film 932 is arranged on the lower wall of the first flow path 87 so as to cover the opening 87a of the first flow path 87. The film 932 has flexibility and can be elastically deformed. The film 932 deforms in response to changes in the pressure of ink within the damper chamber 931, changing the volume of the damper chamber 931.

The damper 93 alleviates pressure fluctuations in the ink within the first flow path 87 . Thereby, the load on the recording head 52 due to ink pulsation can be suppressed. In addition, in order to follow the amplitude period of the pump, it is desirable that the configuration utilizes an elastic member such as a spring.

The second flow path 94 extends from the syringe 86 to the sub-tank 83. A fourth conduit 941 of the second flow path 94 is inserted into the syringe 86 (see FIG. 5). The second flow path 94 is an air flow path that discharges the air within the syringe 86 to the sub-tank 83. A check valve CV3 is arranged on the fourth conduit 941. The check valve CV3 prevents air from flowing backward from the downstream side to the upstream side with respect to the air flow direction of the second flow path 94.

The third on-off valve 95 is arranged on the fourth conduit 941 of the second flow path 94 on the downstream side of the check valve CV3 in the air flow direction. The configuration and operation of the third on-off valve 95 are the same as those of the first on-off valve 91 described above, and the description thereof will be omitted here. The third on-off valve 95 opens and closes the second flow path 94 . The third on-off valve 95 is composed of, for example, a solenoid valve, and its opening and closing are controlled by the control unit 7.

Then, the control unit 7 closes the third on-off valve 95 when executing the forced circulation mode, and opens the third on-off valve 95 when the air in the syringe 86 is discharged. Thereby, when the forced circulation mode is executed, ink on the upstream side in the ink circulation direction with respect to the recording head 52 can be pushed out toward the recording head 52. Furthermore, when the air in the syringe 86 is discharged, the air in the syringe 86 can be discharged to the sub-tank 83.

The third flow path 96 connects the first flow path 87 downstream of the supply pump 84 in the ink flow direction and the second flow path 94 downstream of the third on-off valve 95 in the air flow direction.

Relief valve 97 is arranged in third flow path 96 . The relief valve 97 is opened when the channel internal pressure on the first channel 87 side reaches a predetermined pressure. This makes it possible to prevent excessive pressure from being applied to the conduit when an abnormality occurs in the ink flow path. In addition, it is possible to prevent ink from leaking into the apparatus.

The fourth flow path 98 connects the upstream and downstream sides of the first flow path 87 in the ink flow direction of the recording head 52 . Specifically, the fourth channel 98 connects the second conduit 872 of the first channel 87 and the third conduit 873 in the ink supply section 8 in the vicinity of the coupling 11 .

The opening/closing mechanism 99 is arranged on the fourth flow path 98. The opening/closing mechanism 99 includes, for example, a clamp that can manually open and close the fourth flow path 98. The opening/closing mechanism 99 opens and closes the fourth flow path 98 .

When the inkjet recording apparatus 1 is shipped from the factory, the ink supply section 8 is opened to the atmosphere in the sub-tank 83. As a result, the ink supply section 8 side does not contain ink, transport liquid, etc. because there is a concern that liquid may leak during transportation. On the other hand, the recording head 52 side is filled with transport liquid in order to ensure the quality of the flow path and to take initial filling properties into consideration. Therefore, if the recording head 52 is connected without first filling the ink supply section 8 with ink upon arrival, there is a concern that the transport liquid may leak from the recording head 52 and contaminate the inside of the apparatus. Therefore, in order to fill the channel on the ink supply section 8 side with ink when the coupling 11 between the ink supply section 8 and the head unit 51 is removed, a fourth channel 98 is provided, and an opening/closing mechanism 99 is provided. It will be released. The opening/closing mechanism 99 is closed during normal operation of the device.

Although the embodiments of the present invention have been described above, the scope of the present invention is not limited thereto, and various modifications can be made without departing from the gist of the invention.

The present invention can be used in an inkjet recording device.

1 Inkjet recording device 5 Recording section 7 Control section 8 Ink supply section 11 Coupling 52 Recording head 81 Ink container 82 Container pump 83 Sub-tank 84 Supply pump 85 Circulation pump 86 Syringe 87 First flow path 91 First on-off valve 92 Second on-off valve Valve 93 Damper 94 Second channel 95 Third opening/closing valve 96 Third channel 97 Relief valve 98 Fourth channel 99 Opening/closing mechanism 521 Ink discharge nozzle S Paper (recording medium)

Claims (7)

a recording head having a plurality of nozzles that ejects ink onto a recording medium;
an ink container containing the ink to be supplied to the recording head;
a sub-tank that temporarily stores the ink supplied from the ink container;
a supply pump that supplies the ink from the sub-tank to the recording head;
a circulation pump that circulates the ink from the recording head to the sub tank;
a syringe in which the ink flows in from the supply pump and flows out toward the recording head, and is capable of applying a maintenance pressure to the ink that is higher than the recording pressure applied by the supply pump;
a first flow path through which the ink circulates from the sub-tank to the sub-tank via the supply pump, the syringe, the recording head, and the circulation pump;
a control unit that controls operations of the recording head, the supply pump, the circulation pump, and the syringe to record an image on the recording medium;
Equipped with
The control unit is capable of executing a forced circulation mode in which the maintenance pressure is applied to the ink by the syringe to force the ink to flow downstream in the ink circulation direction of the syringe during non-image recording. An inkjet recording device featuring: The control unit is capable of executing a cleaning mode in which the ink is forcibly pushed out from the nozzles to clean the recording head during non-image recording, and executes the forced circulation mode when executing the cleaning mode. The inkjet recording apparatus according to claim 1, characterized in that: a first on-off valve that opens and closes the first flow path between the supply pump and the syringe;
a second on-off valve that opens and closes the first flow path between the syringe and the recording head;
Equipped with
3. The inkjet recording apparatus according to claim 1, wherein the control unit closes the first on-off valve and opens the second on-off valve when executing the forced circulation mode. A claim further comprising a damper disposed between the supply pump and the syringe and between the recording head and the circulation pump to alleviate pressure fluctuations of the ink in the first flow path. An inkjet recording apparatus according to any one of claims 1 to 3. a second flow path extending from the syringe to the sub-tank and discharging air in the syringe to the sub-tank;
a third on-off valve that opens and closes the second flow path;
Equipped with
Claims 1 to 4, wherein the control unit closes the third on-off valve when executing the forced circulation mode, and opens the third on-off valve when the air in the syringe is discharged. The inkjet recording device according to any one of the above. a third flow path connecting a downstream side of the first flow path in the ink flow direction with respect to the supply pump and a downstream side of the second flow path with respect to the air flow direction of the third on-off valve;
a relief valve disposed in the third channel and opened when the channel internal pressure on the first channel side reaches a predetermined pressure;
The inkjet recording apparatus according to claim 5, further comprising: a fourth flow path connecting an upstream side and a downstream side of the first flow path in the ink flow direction of the recording head;
an opening and closing mechanism that opens and closes the fourth flow path;
The inkjet recording apparatus according to any one of claims 1 to 6, characterized by comprising:

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