Inkjet recording device

Abstract

To suppress contamination of a recording head caused by blowing-back of ink.SOLUTION: An inkjet recording device includes a transport belt for conveying a recording medium, a recording head, a control part, and an ink collection part. The transport belt has multiple openings. The control part causes the recording head to perform processing of discharging ink toward the opening that does not overlap with the recording medium as flushing processing. The ink collection part includes: an ink receiving section that is arranged opposite in the prescribed direction to the recording head across the transport belt and receives flushing ink; a suction mechanism that suctions gas from the ink receiving section; a duct that is arranged between the ink receiving section and the transport belt in the prescribed direction to guide the flushing ink to the ink receiving section; and a rotating body that is arranged inside the duct and rotates around an axis extending in the prescribed direction.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an inkjet recording apparatus. [Background technology]

[0002] Conventionally, inkjet recording devices equipped with a recording head are known. The recording head has nozzles for ejecting ink. The recording head ejects ink onto a recording medium being transported by a transport belt. In this way, an image is recorded on the recording medium. Such an inkjet recording device is disclosed in, for example, Patent Document 1.

[0003] In conventional inkjet recording devices, a flushing process is performed on the recording head to prevent clogging of the nozzles. The conveyor belt has an opening to collect the ink ejected during the flushing process. An ink receiving section is disposed at a position facing the recording head across the conveyor belt (in other words, the conveying path of the recording medium). In the flushing process, ink is ejected toward the opening of the conveyor belt. This causes the ink to pass through the opening of the conveyor belt and reach the ink receiving section. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-11057 Summary of the Invention [Problem to be solved by the invention]

[0005] In a conventional inkjet recording device, mist-like ink may accumulate in the ink receiver. When mist-like ink accumulates in the ink receiver, the ink may be blown back toward the recording head, causing problems such as contaminating the recording head. For example, when ink blown back from the ink receiver adheres to the nozzle surface of the recording head, ink ejection failure occurs in the recording head, resulting in a deterioration in image quality.

[0006] The present invention has been made to solve the above-mentioned problems, and has an object to provide an inkjet recording apparatus capable of suppressing contamination of the recording head caused by ink spit-back. [Means for solving the problem]

[0007] In order to achieve the above object, the inkjet recording device of the present invention includes a conveyor belt for conveying a recording medium, a recording head for recording an image on the recording medium by ejecting ink onto the recording medium being conveyed by the conveyor belt, a control unit for controlling a flushing process by the recording head, and an ink recovery unit for recovering ink not used for recording the image. The conveyor belt has a plurality of openings penetrating the conveyor belt in a thickness direction. The control unit causes the recording head to perform a process of ejecting ink toward the openings that do not overlap with the recording medium as a flushing process. The ink recovery unit is disposed opposite the recording head in a predetermined direction across the conveyor belt, and includes an ink receiving unit for receiving flushing ink ejected from the recording head and passing through the openings during the flushing process, a suction mechanism for sucking gas from the ink receiving unit, a duct disposed between the ink receiving unit and the conveyor belt in the predetermined direction and for guiding the flushing ink to the ink receiving unit, and a rotor disposed inside the duct and rotating about an axis extending in the predetermined direction. Effect of the Invention

[0008] The configuration of the present invention can suppress contamination of the recording head caused by ink spit-back. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of an inkjet recording apparatus according to an embodiment. [Diagram 2] 1 is a plan view of a printing unit of an inkjet printing apparatus according to an embodiment. [Diagram 3] 1 is a block diagram of an inkjet recording apparatus according to an embodiment. [Figure 4] FIG. 2 is a plan view of a transport belt of the inkjet recording apparatus according to the embodiment. [Diagram 5] 2 is a schematic diagram of the periphery of a conveyor belt of an inkjet recording apparatus according to an embodiment. [Figure 6] 2 is a schematic diagram of an ink recovery unit of an inkjet recording apparatus according to an embodiment. FIG. [Figure 7] 7 is a diagram showing a schematic diagram of a distribution path of flushing ink inside a duct of the ink recovery unit shown in FIG. 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An inkjet recording apparatus according to an embodiment of the present invention will be described below with reference to Figures 1 to 7, taking a printer 100 as an example. The printer 100 is installed on a flat floor surface and used in this state. In the following description, the direction perpendicular to the flat floor surface on which the printer 100 is installed is defined as the up-down direction.

[0011] The printer 100 also records an image on a sheet S as a recording medium. That is, the printer 100 prints an image on the sheet S. Paper is mainly used as the sheet S. Other sheets S such as overhead projector sheets can also be used. Cloth, cardboard, and the like may also be used as the recording medium.

[0012] <Printer configuration> As shown in FIG. 1, a printer 100 (corresponding to an "inkjet recording device") of this embodiment includes a first transport unit 1 and a second transport unit 2. The first transport unit 1 feeds a sheet S (corresponding to a "recording medium") set in a paper feed cassette CA, and transports the sheet S toward a recording position. In a print job by the printer 100, an image is recorded (printed) on the sheet S that passes the recording position. The second transport unit 2 transports the sheet S on which recording has been performed. The second transport unit 2 discharges the sheet S on which recording has been performed onto a discharge tray ET.

[0013] The first conveying section 1 includes a plurality of conveying roller members including a registration roller pair 11. In FIG. 1, only the registration roller pair 11 among the plurality of conveying roller members is labeled with a reference symbol. Each of the plurality of conveying roller members conveys the sheet S by rotating. The registration roller pair 11 includes a pair of rollers that are in pressure contact with each other. A registration nip is formed between the pair of rollers. The sheet S fed from a paper feed cassette CA enters the registration nip. The registration roller pair 11 rotates to convey the sheet S that has entered the registration nip toward the belt conveying section 3 described later.

[0014] When the leading edge of the sheet S reaches the registration nip, the registration roller pair 11 stops rotating. On the other hand, the transport roller member upstream of the registration roller pair 11 in the transport direction DC of the sheet S is rotating. This causes the skew of the sheet S to be corrected.

[0015] The printer 100 includes a belt conveyor 3. The belt conveyor 3 receives the sheet S from the first conveyor 1 and conveys the sheet S. The belt conveyor 3 includes a conveyor belt 30. The conveyor belt 30 is endless and supported so as to be rotatable. The belt conveyor 3 also includes a plurality of tension rollers 301. The plurality of tension rollers 301 are supported so as to be rotatable. The conveyor belt 30 is tensioned by the plurality of tension rollers 301 and rotates. The sheet S conveyed from the first conveyor 1 reaches the outer circumferential surface of the conveyor belt 30.

[0016] One of the multiple tension rollers 301 is connected to a belt motor (not shown) and rotates by power transmitted from the belt motor. When the tension roller 301 connected to the belt motor rotates, the conveyor belt 30 rotates accordingly. At this time, the other tension rollers 301 also rotate accordingly.

[0017] The belt conveying section 3 also includes a suction unit 300. The suction unit 300 is disposed inside the conveying belt 30. The conveying belt 30 has a plurality of suction holes (not shown) penetrating in the thickness direction of the conveying belt 30. The suction unit 300 sucks the sheet S on the outer circumferential surface of the conveying belt 30 through the suction holes of the conveying belt 30. The sheet S is attracted to the outer circumferential surface of the conveying belt 30 by the suction force of the suction unit 300.

[0018] The conveyor belt 30 adsorbs and holds the sheet S on its outer circumferential surface. That is, the conveyor belt 30 has its outer circumferential surface as a carrying surface for the sheet S. The conveyor belt 30 is driven (i.e., rotates) in a state in which the sheet S is adsorbed and held on its outer circumferential surface. In this way, the sheet S is conveyed by the conveyor belt 30.

[0019] The direction indicated by the symbol DC in the figure is the conveying direction of the sheet S by the conveyor belt 30. For example, although not shown, a mechanism for separating the sheet S from the outer circumferential surface of the conveyor belt 30 is disposed at the downstream end of the conveyor belt 30 in the conveying direction DC of the sheet S. This prevents the sheet S from rotating while being attracted and held by the conveyor belt 30.

[0020] The printer 100 includes a recording unit 4. The recording unit 4 is disposed above the conveyor belt 30. The recording unit 4 faces the outer circumferential surface of the conveyor belt 30 at a distance in the vertical direction. The recording unit 4 includes a plurality of (four) line heads 41 corresponding to the colors cyan, magenta, yellow, and black, respectively. The plurality of line heads 41 are arranged as shown in FIG. 2 when viewed from above. In FIG. 2, the cyan line head 41 is given the symbol "C", the magenta line head 41 is given the symbol "M", the yellow line head 41 is given the symbol "Y", and the black line head 41 is given the symbol "K" to distinguish them from one another. The same applies to FIG. 5, which will be referred to later in the description.

[0021] The line head 41 of each color includes multiple (e.g., three) recording heads 40. For example, the multiple recording heads 40 of each color are arranged in a staggered pattern in a direction perpendicular to the conveying direction DC of the sheet S by the conveyor belt 30. In the following description, the direction perpendicular to the conveying direction DC of the sheet S by the conveyor belt 30 may be simply referred to as the width direction.

[0022] Each recording head 40 is disposed above the conveyor belt 30. Each recording head 40 faces the outer circumferential surface of the conveyor belt 30 at an interval in the vertical direction. In other words, each recording head 40 is disposed at a position facing the sheet S conveyed by the conveyor belt 30 in the vertical direction. In further other words, the conveyor belt 30 adsorbs and holds the sheet S below each recording head 40 and conveys it. As a result, the space between each recording head and the conveyor belt 30 in the vertical direction becomes part of the conveying path of the sheet S.

[0023] Each recording head 40 has a nozzle surface that faces the outer peripheral surface of the conveyor belt 30 in the vertical direction. The nozzle surface of each recording head 40 has a plurality of nozzles 4N. The plurality of nozzles 4N of each recording head 40 ejects ink of a corresponding color downward. For example, the number of nozzles 4N of each recording head 40 is the same. The plurality of nozzles 4N of each recording head 40 are arranged along the width direction of the conveyor belt 30. In FIG. 2, the nozzles 4N are indicated by dashed lines. Note that, in reality, more nozzles 4N are provided in each recording head 40. In FIG. 2, for convenience, only some of the nozzles 4N are indicated by symbols.

[0024] Each recording head 40 ejects ink from the nozzles 4N toward the sheet S on the outer circumferential surface of the conveyor belt 30 based on image data to be recorded on the sheet S in a print job. The ink ejected from each recording head 40 lands on the sheet S. This causes an image to be recorded on the sheet S. In other words, the space between each recording head 40 and the conveyor belt 30 is a recording position, and an image is recorded on the sheet S at that recording position.

[0025] Here, the viscosity of ink remaining in the nozzles 4N that eject ink less frequently among the multiple nozzles 4N increases over time. As a result, clogging occurs and image quality deteriorates. To prevent such problems, each recording head 40 performs a flushing process. In the flushing process by each recording head 40, ink remaining in the nozzles 4N is ejected. This prevents clogging. The flushing process will be described in detail later.

[0026] Returning to FIG. 1, the printer 100 includes a drying unit 51 and a decurler 52. The drying unit 51 dries the ink adhering to the sheet S while transporting the sheet S toward the decurler 52. The decurler 52 straightens out curls in the sheet S. The decurler 52 transports the sheet S after the curl has been straightened toward the second transport section 2.

[0027] As shown in FIG. 3, the printer 100 also includes a control unit 6. The control unit 6 includes processing circuits such as a CPU and an ASIC. The control unit 6 controls print jobs. In other words, the control unit 6 controls the operations of the first conveying unit 1, the second conveying unit 2, the belt conveying unit 3, the recording unit 4, the drying unit 51, and the decurler 52. In other words, the control unit 6 controls the conveyance of the sheet S by the conveyor belt 30. The control unit 6 controls the recording of an image on the sheet S by each recording head 40 (i.e., the ejection of ink onto the sheet S). The control unit 6 also controls the flushing process by each recording head 40.

[0028] A registration sensor 61, a sheet sensor 62, and a belt sensor 63 are connected to the control unit 6. The control unit 6 controls the conveyance of the sheet S and the recording of an image on the sheet S based on the outputs of the registration sensor 61, the sheet sensor 62, and the belt sensor 63.

[0029] The registration sensor 61 has a detection position that is upstream of the registration nip in the conveying direction DC of the sheet S. The registration sensor 61 is, for example, a reflective or transmissive optical sensor. The registration sensor 61 changes an output value depending on the presence or absence of the sheet S at the corresponding detection position.

[0030] The control unit 6 detects the arrival of the leading end of the sheet S at the detection position of the registration sensor 61 and the passage of the trailing end thereof based on the output value of the registration sensor 61. In other words, the control unit 6 detects the arrival of the leading end of the sheet S at the registration nip and the passage of the trailing end thereof based on the output value of the registration sensor 61. The control unit 6 measures the timing at which the registration roller pair 11 starts conveying the sheet S (the timing at which the registration roller pair 11 starts rotating) based on the elapsed time after the registration sensor 61 detects the arrival of the leading end of the sheet S at its detection position.

[0031] The sheet sensor 62 has a detection position between the recording position of the line head 41 located most upstream in the conveying direction DC of the sheet S among the multiple line heads 41 and the registration nip. The sheet sensor 62 changes an output value depending on the presence or absence of the sheet S at the corresponding detection position. A CIS (Contact Image Sensor) may be used as the sheet sensor 62. A reflective or transmissive optical sensor may also be used as the sheet sensor 62. For example, a CIS is used as the sheet sensor 62.

[0032] The control unit 6 detects the arrival of the leading end and the passing of the trailing end of the sheet S at the detection position of the sheet sensor 62 based on the output value of the sheet sensor 62. The control unit 6 measures the timing of ejecting ink onto the sheet S transported by the transport belt 30 based on the output value of the sheet sensor 62. Note that the timing of ejecting ink onto the sheet S transported by the transport belt 30 may be measured based on the elapsed time from when the pair of registration rollers 11 starts transporting the sheet S.

[0033] Furthermore, the control unit 6 measures the paper passing time taken from when the leading edge of the sheet S reaches the detection position of the sheet sensor 62 until the trailing edge of the same sheet S passes the detection position of the sheet sensor 62. The paper passing time at the detection position of the sheet sensor 62 varies depending on the size of the sheet S in the transport direction DC. Therefore, the control unit 6 recognizes the size of the sheet S in the transport direction DC transported by the conveyor belt 30 based on the paper passing time. This allows the control unit 6 to recognize the size of the sheet S in the transport direction DC even if the sheet S transported by the conveyor belt 30 is of an irregular size.

[0034] The belt sensor 63 is a sensor for detecting a predetermined reference position (home position) of the conveyor belt 30. For example, a predetermined mark is provided at the reference position of the conveyor belt 30. This makes it possible to detect the reference position of the conveyor belt 30 based on the output value of the belt sensor 63. A CIS may be used as the belt sensor 63. Also, a transmissive or reflective optical sensor may be used as the belt sensor 63.

[0035] The control unit 6 detects the reference position of the conveyor belt 30 based on the output value of the belt sensor 63. In other words, the control unit 6 detects the position of a flushing area FA (flushing hole 31) described later based on the output value of the belt sensor 63.

[0036] The printer 100 also includes a storage unit 601. The storage unit 601 includes storage devices such as a ROM and a RAM. The storage unit 601 is connected to the control unit 6. The control unit 6 reads information from the storage unit 601. The control unit 6 also writes information to the storage unit 601.

[0037] The printer 100 includes an operation unit 602. The operation unit 602 includes, for example, a touch screen. The touch screen displays software buttons and messages, and receives touch operations from the user. The operation unit also includes hardware buttons for receiving settings and instructions. The operation unit 602 is connected to the control unit 6. The control unit 6 controls the display operation of the operation unit 602 (touch screen). The control unit 6 also detects operations performed on the operation unit 602.

[0038] The printer 100 includes a communication unit 603. The communication unit 603 includes a communication circuit and the like. The communication unit 603 is connected to a user terminal PC via a network NT. The user terminal PC is an information processing device such as a personal computer. The control unit 6 communicates with the user terminal PC using the communication unit 603. For example, print data (such as PDL data) including image data to be recorded on a sheet S in a print job is transmitted from the user terminal PC to the printer 100. In other words, a request to execute a print job is transmitted from the user terminal PC to the printer 100. The print data of the print job includes various setting data related to printing, such as the size of the sheet S used in the print job.

[0039] <Flushing process overview> As shown in Fig. 4, the conveyor belt 30 has a flushing area FA. In Fig. 4, the flushing area FA is surrounded by a dashed line. The flushing area FA is an area including flushing holes 31, which are through holes penetrating the conveyor belt 30 in the thickness direction. The flushing holes 31 correspond to "openings."

[0040] A plurality of flushing areas FA are provided on the conveyor belt 30. The plurality of flushing areas FA are arranged at predetermined intervals from each other in the rotation direction of the conveyor belt 30 (the conveying direction DC of the sheet S). Each flushing area FA includes a plurality of flushing holes 31. The opening shape of the flushing holes 31 (the shape seen from the thickness direction of the conveyor belt 30) is not particularly limited. The shape of the flushing holes 31 may be a circle, an ellipse, an oval, or a rectangle. Each of the plurality of nozzles 4N faces at least one of the flushing holes 31 in the vertical direction by the rotation of the conveyor belt 30.

[0041] The flushing process involves ejecting ink from each nozzle 4N. When the flushing process is performed, ink is ejected from each nozzle 4N at a timing that vertically faces the flushing hole 31. The ink passes through the flushing hole 31. As a result, even when the flushing process is performed, the ink does not adhere to the conveyor belt 30. In the following description, the ink ejected from each nozzle 4N when the flushing process is performed is referred to as flushing ink, and is distinguished from ink that contributes to image recording on the sheet S. Ink that does not contribute to image recording on the sheet S is called flushing ink.

[0042] During execution of a print job, the control unit 6 causes each recording head 40 to perform a flushing process. The control unit 6 controls the flushing ink ejected from each recording head 40 to pass through the flushing holes 31 and reach the inside of the conveyor belt 30.

[0043] Specifically, the control unit 6 times the start timing of conveying the sheet S from the pair of registration rollers 11 to the conveyor belt 30 so that the flushing area FA appears periodically between the sheets (the gap between the rear end of the preceding sheet S and the front end of the next sheet S). Then, the control unit 6 ejects ink from each nozzle 4N at a timing that faces the flushing hole 31 that is not overlapping the sheet S in the vertical direction. In other words, the control unit 6 ejects ink from each nozzle 4N toward the flushing hole 31 that is not overlapping the sheet S. In yet other words, the control unit 6 ejects ink from each nozzle 4N at a timing different from the timing of recording an image onto the sheet S.

[0044] <Collecting Flushing Ink> As shown in Fig. 5, the printer 100 includes an ink recovery unit 10. The ink recovery unit 10 is disposed on the inner side of the transport belt 30. In the flushing process, flushing ink passes through flushing holes 31 in the transport belt 30 and reaches the inner side of the transport belt 30. The ink recovery unit 10 recovers and stores the ink by sucking the ink. In Fig. 5, the suction direction of the flushing ink is indicated by a solid black arrow. The white arrow indicates the suction direction by the suction unit 300.

[0045] A plurality of ink recovery units 10 are provided. One ink recovery unit 10 is assigned to each line head 41. One ink recovery unit 10 is assigned to each of the colors cyan, magenta, yellow, and black. In other words, the printer 100 has four ink recovery units 10 corresponding to the colors cyan, magenta, yellow, and black, respectively. Each of the four ink recovery units 10 recovers and stores the flushing ink ejected from the corresponding line head 41.

[0046] The following describes the configuration of one ink recovery unit 10. The ink recovery units 10 have the same configuration. Therefore, the configurations of the other ink recovery units 10 will be omitted as the following description is incorporated herein.

[0047] The ink recovery unit 10 has an ink receiving unit 7. The ink receiving unit 7 is disposed so as to face the recording head 40 that ejects ink of a corresponding color in the vertical direction across the conveyor belt 30. In this configuration, the vertical direction corresponds to the "predetermined direction".

[0048] The ink receiving section 7 receives the flushing ink that has passed through the flushing holes 31 of the transport belt 30. The ink receiving section 7 stores the flushing ink. The ink receiving section 7 is a container having an internal area as a storage area for the flushing ink. The container as the ink receiving section 7 has a receiving port 7a on the upper surface portion, which is the portion facing the recording head 40 across the transport belt 30. The flushing ink is collected in the storage area of ​​the ink receiving section 7 through the receiving port 7a.

[0049] For example, the ink receiving unit 7 is detachable from the main body of the printer 100. This allows flushing ink accumulated in the storage area of ​​the ink receiving unit 7 to be discarded. Alternatively, the ink receiving unit 7 can be replaced.

[0050] The ink recovery unit 10 has a suction mechanism 70 (see FIG. 3). The suction mechanism 70 is connected to the ink receiving unit 7. The suction mechanism 70 sucks gas from inside the ink receiving unit 7. The suction mechanism 70 is, for example, a mechanism including a suction fan. The control unit 6 controls the suction mechanism 70 (suction fan).

[0051] The ink recovery section 10 has a duct 8. The duct 8 is a cylindrical body with its cylindrical axis extending in the vertical direction. The duct 8 is disposed between the inner circumferential surface of the conveyor belt 30 and the upper surface of the ink receiving section 7 in the vertical direction. One opening of the duct 8 in the vertical direction is adjacent to the inner circumferential surface of the conveyor belt 30 in the vertical direction. The other opening of the duct 8 in the vertical direction is connected to the receiving port 7a of the ink receiving section 7. The duct 8 serves as a flow path for the mist-like flushing ink (and the gas containing it).

[0052] The duct 8 communicates with the ink receiving unit 7. In this configuration, when the suction mechanism 70 is driven, an airflow from above to below is generated inside the duct 8. As a result, the duct 8 guides the mist-like flushing ink that has passed through the flushing holes 31 of the conveyor belt 30 to the receiving port 7a of the ink receiving unit 7.

[0053] Here, as shown in Fig. 6, the ink recovery unit 10 has a rotating body 9. The rotating body 9 is disposed inside the duct 8. The rotating body 9 rotates about an axis extending in the vertical direction (corresponding to the "predetermined direction"). In Fig. 5, the rotating body 9 is omitted from illustration.

[0054] The rotating body 9 has a hub 90. The hub 90 is disposed at the center of the rotating body 9 when viewed from the top-bottom direction. The rotating body 9 has a plurality of blades 91. The plurality of blades 91 may be integrally provided on the hub 90. The plurality of blades 91 extend radially outward from a side surface of the hub 90 facing radially outward (i.e., the outer peripheral surface of the hub 90) when viewed from the top-bottom direction. The radially outward direction is the direction away from the center of the rotating body 9 when viewed from the top-bottom direction. The plurality of blades 91 are also arranged in the rotational direction of the rotating body 9.

[0055] For example, the rotor 9 rotates due to an airflow generated inside the duct 8 by driving the suction mechanism 70. In this configuration, the drive unit M, which will be described later, is not required.

[0056] Alternatively, the rotating body 9 is rotated by power transmitted from a drive unit M (see FIG. 3). In this configuration, the ink recovery unit 10 has the drive unit M. The drive unit M is a motor and is capable of forward and reverse rotation. The control unit 6 controls the drive unit M to appropriately rotate the rotating body 9.

[0057] The rotor 9 is attached to the duct 8. For example, although not shown, an L-shaped support rod may be fixed inside the duct 8, and the rotor 9 may be rotatably attached to the support rod. In addition, when a rotor 9 having a casing that covers the hub 90 and the multiple blades 91 is used, the casing of the rotor 9 may be attached to the duct 8.

[0058] In this embodiment, a rotor 9 is disposed inside the duct 8, and by rotating the rotor 9, an airflow as shown in Fig. 7 is generated inside the duct 8. In Fig. 7, the airflow inside the duct 8 is shown typically by arrows. In Fig. 7, the reference numeral for the rotor 9 is omitted in order to make the drawing easier to understand. The reference numeral for the rotor 9 is shown in Fig. 6.

[0059] 7, the backflow of the mist-like flushing ink is suppressed inside the duct 8 where the airflow is generated. Even if the mist-like flushing ink blows back from the ink receiving section 7, the mist-like flushing ink is less likely to reach the recording head 40.

[0060] Specifically, the airflow around the rotating body 9 can prevent the mist-like flushing ink blown back from the ink receiving section 7 from passing over the rotating body 9 toward the recording head 40. Furthermore, the main body of the rotating body 9 itself, such as the hub 90 and the blades 91, can act as an obstacle, preventing the mist-like flushing ink blown back from the ink receiving section 7 from passing over the rotating body 9 toward the recording head 40. This can prevent the mist-like flushing ink from accumulating inside the duct 8. In FIG. 7, the distribution path of the flushing ink blown back is shown diagrammatically by dashed arrows, and the distribution path of the flushing ink whose flow direction has been reversed by the rotating body 9 is shown by thick arrows.

[0061] If the mist-like flushing ink were to stagnate inside the duct 8, the stagnant ink could be blown back toward the recording head 40 and adhere to the nozzle surface (i.e., the nozzle surface of the recording head 40 would become contaminated), which could be an inconvenience.

[0062] On the other hand, when the retention of the mist of flushing ink inside the duct 8 is suppressed, the ink that can adhere to the nozzle surface of the recording head 40 (i.e., the retained ink) is reduced. In other words, the blowback of the mist of flushing ink inside the duct 8 can be suppressed. This makes it possible to prevent the nozzle surface of the recording head 40 from being contaminated by the flushing ink. As a result, it is possible to suppress deterioration of image quality caused by poor ink ejection.

[0063] In this embodiment, the duct 8 has a first duct portion 81 and a second duct portion 82. The first duct portion 81 is located on the conveyor belt 30 side. The second duct portion 82 is located on the ink receiving portion 7 side of the first duct portion 81. That is, the upper portion of the duct 8 is the first duct portion 81, and the other lower portion is the second duct portion 82. The first duct portion 81 is adjacent to the inner circumferential surface of the conveyor belt 30 in the up-down direction. The second duct portion 82 is connected to the receiving port 7a of the ink receiving portion 7.

[0064] The opening areas (areas of the openings when viewed from the top-bottom direction) of the first duct portion 81 and the second duct portion 82 are different from each other. The opening area of ​​the second duct portion 82 is smaller than that of the first duct portion 81. Note that the connecting portion 82a of the second duct portion 82 with the first duct portion 81 has a tapered shape from top to bottom. As a result, the inner wall surface of the connecting portion 82a of the second duct portion 82 is inclined with respect to the top-bottom direction.

[0065] By using the duct 8 having the first duct portion 81 and the second duct portion 82, the flow path formed inside the duct 8 narrows from the top to the bottom (i.e., from the conveyor belt 30 side to the ink receiving portion 7 side). This makes it possible to improve the suction force from the top to the bottom inside the duct 8. In addition, the suction airflow from the top to the bottom inside the duct 8 collides with the inclined surface of the second duct portion 82, making it easier to guide the mist-like flushing ink to the ink receiving portion 7.

[0066] The rotating body 9 is disposed on the boundary side of the first duct portion 81 with the second duct portion 82 (i.e., on the lower side of the first duct portion 81). By disposing the rotating body 9 inside the first duct portion 81, it is not necessary to reduce the size of the rotating body 9. In addition, the blowback of the mist-like flushing ink can be blocked at a position relatively far away from the recording head 40. This makes it possible to further suppress the adhesion of the flushing ink to the nozzle surface of the recording head 40.

[0067] In this embodiment, when the inside of duct 8 is viewed from the top to bottom direction (corresponding to the "predetermined direction"), the total area of ​​the regions blocked by the multiple blades 91 is equal to or less than half the area of ​​a circle whose circumference is the movement path of the radially outermost ends of the blades 91 when the rotor 9 is rotated. In other words, if the circular area is Sa and the total area is Sb, then the following formula (1) is established. Sb≦Sa / 2 (1)

[0068] In this configuration, the gap between the adjacent vanes 91 in the rotation direction of the rotor 9 is relatively large, and the mist-like flushing ink can easily pass through the gap. This makes it possible to further prevent the mist-like flushing ink from accumulating inside the duct 8.

[0069] When the driving unit M is not used, the complexity of the structure and the increase in the number of parts can be suppressed, and costs can be reduced. On the other hand, when the driving unit M is used, the following control can be performed.

[0070] Specifically, the control unit 6 rotates the rotating body 9 using the drive unit M when the flushing process is performed by the recording head 40. This promotes the flow of the mist of flushing ink from above to below inside the duct 8, and can further suppress the accumulation of the mist of flushing ink.

[0071] The control unit 6 changes the amount of flushing ink ejected from each nozzle 4N of the recording head 40. For example, the frequency of flushing processing during execution of a print job varies depending on the size of the sheet S used in the print job. The lower the frequency of flushing processing, the higher the ink viscosity tends to become. For this reason, the lower the frequency of flushing processing, the greater the amount of flushing ink ejected.

[0072] In this configuration, the control unit 6 controls the drive unit M based on the amount of flushing ink ejected from each nozzle 4N of the recording head 40, and changes the rotation speed of the rotating body 9. For example, the control unit 6 increases the rotation speed of the rotating body 9 as the amount of flushing ink ejected from each nozzle 4N of the recording head 40 increases. This makes it possible to prevent the amount of flushing ink remaining inside the duct 8 from increasing due to a large amount of flushing ink ejected.

[0073] In addition, for example, the rotational force (i.e., suction force) can be improved by rotating the rotor 9 counterclockwise in the northern hemisphere and rotating the rotor 9 clockwise in the southern hemisphere. Therefore, the rotation direction of the rotor 9 may be changeable.

[0074] The embodiments disclosed herein are illustrative in all respects and should not be considered as limiting. The scope of the present invention is indicated by the claims, not by the description of the above embodiments, and further includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0075] 6. Control Unit 7 Ink receiver 8 Duct 9 Rotating Body 10 Ink recovery section 30 Conveyor belt 31 Flushing hole (opening) 40 Recording head 70 Suction mechanism 81 First Duct Section 82 Second duct section 100 Printers (inkjet recording devices) M Drive Unit S sheet (recording medium)

Claims

1. A conveyor belt for conveying a recording medium; a recording head that records an image on the recording medium by ejecting ink onto the recording medium being conveyed by the conveyor belt; A control unit that controls a flushing process by the recording head; an ink recovery unit that recovers the ink that is not used in recording the image, the conveyor belt has a plurality of openings penetrating in a thickness direction of the conveyor belt, the control unit causes the recording head to perform a process of ejecting the ink toward the opening that does not overlap with the recording medium as the flushing process; The ink recovery unit includes: an ink receiving section disposed opposite the recording head in a predetermined direction with the conveyor belt interposed therebetween, and receiving flushing ink that is discharged from the recording head and passes through the opening during the flushing process; a suction mechanism for suctioning gas from the ink receiving portion; a duct disposed between the ink receiving section and the conveyor belt in the predetermined direction, the duct directing the flushing ink to the ink receiving section; a rotating body that is disposed inside the duct and rotates about an axis extending in the predetermined direction.

2. The duct is A first duct portion located on the conveyor belt side; 2. The ink jet recording apparatus according to claim 1, further comprising: a second duct portion located closer to the ink receiving portion than the first duct portion and having an opening area smaller than that of the first duct portion.

3. The inkjet recording apparatus according to claim 2 , wherein the rotating body is disposed on a boundary side between the first duct portion and the second duct portion.

4. The rotor has a plurality of blades arranged in a rotation direction of the rotor, 2. The inkjet recording device according to claim 1, wherein when the inside of the duct is viewed from the specified direction, the total area of ​​the region blocked by the blades is less than or equal to half the area of ​​a circle whose circumference is the movement trajectory of the radially outermost tip of the blade when the rotating body is rotated.

5. The inkjet recording apparatus according to claim 1 , wherein the rotating body is rotated by an air flow generated inside the duct by driving the suction mechanism.

6. the ink recovery unit has a drive unit that rotates the rotating body, The inkjet recording apparatus according to claim 1 , wherein the control unit rotates the rotating body using the drive unit when the flushing process is performed.

7. The inkjet recording apparatus according to claim 6 , wherein the control unit changes the rotation speed of the rotating body based on the ejection amount of the flushing ink ejected from the recording head.

8. The inkjet recording apparatus according to claim 7 , wherein the rotation direction of the rotating body is changeable.

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