Inkjet recording apparatus

Abstract

An inkjet recording apparatus includes a recording head, a transport member, a control unit, an ink recovery unit, an ink passage, and a suction unit. The ink passing path is formed between the conveying member and the ink receiving portion. The suction part is connected to the ink receiving part and sucks the ink passing through the opening part and air in the ink passing path. The conveyance member has an air flow hole formed on the upstream side of the opening with respect to the conveyance direction. The interval between the opening portion and the air circulation hole in the conveying direction is smaller than the width of the ink passing path in the conveying direction.

Description

Technical Field

[0001] The present invention relates to an inkjet recording device. Background Art

[0002] Conventionally, in order to reduce or prevent nozzle clogging caused by drying of ink, flushing (empty ejection) of ink ejected from the nozzle is performed regularly in inkjet recording devices such as inkjet printers. For example, in an inkjet recording device, an opening is provided on a conveyor belt that conveys a recording medium, so that ink is ejected from each nozzle of a recording head and passes through the opening of the conveyor belt.

[0003] In the above-mentioned inkjet recording device, the ink droplets passing through the opening of the conveyor belt due to flushing usually reach the ink receiving part that receives the ink and are recovered, and then discharged from the ink receiving part as waste liquid. Here, as long as the ink receiving part can be arranged near the ink ejection surface of the recording head, almost all the ink droplets can be recovered by the ink receiving part. However, since the conveyor belt is arranged between the recording head and the ink receiving part, it is difficult to arrange the ink receiving part near the ink ejection surface. As a result, the ink droplets are atomized before reaching the ink receiving part and contaminate the inside of the device. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] An object of the present invention is to provide an inkjet recording apparatus which can allow ink droplets ejected by flushing to efficiently reach an ink receiving portion with a simple structure and can suppress contamination inside the apparatus due to mist.

[0006] (II) Technical solution

[0007] The inkjet recording device of the first structure of the present invention is characterized in that it comprises: a recording head having a plurality of nozzles for ejecting ink; a conveying member having an opening through which the ink ejected from the recording head passes and conveying a recording medium; a control unit that controls the driving of the recording head and the conveying member to perform flushing at a time different from a time that contributes to image recording, that is, to cause the ink to be ejected from the nozzles of the recording head and pass through the opening; and an ink recovery unit having an ink receiving unit, the ink receiving unit being arranged opposite to the recording head with the conveying member interposed therebetween. and receives the ink passing through the opening portion when the flushing is performed; an ink passage path, which is formed between the conveying component and the ink receiving portion, for the ink passing through the opening portion to pass through; and a suction portion, which is connected to the ink receiving portion and sucks the air in the ink passage path and the ink passing through the opening portion, the conveying component is formed with an air circulation hole on the upstream side of the opening portion relative to the conveying direction, and the interval between the opening portion and the air circulation hole in the conveying direction is smaller than the width of the ink passage path in the conveying direction.

[0008] (III) Beneficial effects

[0009] According to the first structure of the present invention, after the opening passes through the upper part of the ink passage path, the air circulation hole is also used to maintain the state in which the inside and outside of the ink passage path are connected. Therefore, the ink droplets can be sucked together with the suction wind, and the ink droplets can be reliably recovered by contacting the contact surface of the ink receiving part. Therefore, the ink will not be retained in the ink passage path, but can be reliably recovered to the ink receiving part, so that the contamination of the conveying parts and the internal contamination of the inkjet recording device can be suppressed, and the image quality can be maintained by flushing. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is an explanatory diagram showing a schematic structure of a printer 100 as an inkjet recording apparatus according to the present invention.

[0011] Figure 2 It is a plan view of the recording unit 9 included in the printer 100 of the present invention.

[0012] Figure 3 1 is an explanatory diagram schematically showing the peripheral structure of a paper conveyance path from the paper feed cassette 2 to the second conveyance unit 12 via the first conveyance unit 5 of the printer 100 of the present invention.

[0013] Figure 4 1 is a block diagram showing the hardware configuration of the main parts of the printer 100 according to the present invention.

[0014] Figure 5Schematic diagram showing the ink recovery section 31Y and a paper conveyance area adjacent to the ink recovery section 31Y.

[0015] Figure 6 This is a side cross-sectional view of the ink recovery section 31Y cut along a direction perpendicular to the conveyance direction.

[0016] Figure 7 It is a plan cross-sectional view of the waste ink tank 33 constituting the ink recovery unit 31Y.

[0017] Figure 8 It is a plan view of the periphery of the opening portion group 82 of the first conveyor belt 8 included in the printer 100 according to the first embodiment of the present invention.

[0018] Fig. 9 It is a plan view showing the positional relationship between the opening portion group 82 of the first conveyor belt 8 and the ink receiving portions 32 a to 32 c in the printer 100 according to the first embodiment.

[0019] Fig.10 This is a side cross-sectional view showing a state in which the most upstream opening 81 of the first conveyor belt 8 passes through the ink receiving portions 32 a to 32 c in the printer 100 according to the first embodiment.

[0020] Fig.11 This is a partial enlarged view of the vicinity of the most upstream opening 81 of the first conveyor belt 8 of the printer 100 according to the first embodiment, and shows the positional relationship between the most upstream opening 81 and the air circulation holes 83 .

[0021] Fig.12 It is a plan view of the periphery of the opening portion group 82 of the first conveyor belt 8 included in the printer 100 according to the second embodiment of the present invention.

[0022] Fig.13 This is a side cross-sectional view showing a state in which the most upstream opening 81 of the first conveyor belt 8 passes through the ink receiving portions 32 a to 32 c in the printer 100 according to the second embodiment.

[0023] Fig.14 It is a partial enlarged view of the vicinity of the most upstream opening 81 of the first conveyor belt 8 of the printer 100 according to the second embodiment, and shows the positional relationship between the most upstream opening 81 and the suction hole 8 a. DETAILED DESCRIPTION

[0024] (1. Structure of inkjet recording device)

[0025] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Figure 11 is an explanatory diagram showing a schematic structure of a printer 100 as an inkjet recording device according to an embodiment of the present invention. The printer 100 includes a paper feed cassette 2 as a paper storage portion. The paper feed cassette 2 is disposed at the lower portion of the printer body 1. Paper P as an example of recording medium is stored in the paper feed cassette 2.

[0026] On the downstream side of the paper feeding cassette 2 in the paper conveying direction, that is, Figure 1 A paper feeding device 3 is arranged above the right side of the paper feeding box 2. Figure 1 As shown, the paper P is separated and fed out one by one toward the upper right of the paper feeding cassette 2 by the paper feeding device 3 .

[0027] The printer 100 includes a first paper conveyance path 4a located in the paper feed direction, that is, above and to the right of the paper feed cassette 2. The paper P fed from the paper feed cassette 2 is conveyed vertically upward along the side of the printer body 1 through the first paper conveyance path 4a.

[0028] In the paper conveying direction, a registration roller pair 13 is provided at the downstream end of the first paper conveying path 4a. In addition, the first conveying unit 5 and the recording section 9 are arranged immediately downstream of the registration roller pair 13 in the paper conveying direction. The paper P fed from the paper feed cassette 2 passes through the first paper conveying path 4a and reaches the registration roller pair 13. The registration roller pair 13 corrects the oblique conveyance of the paper P, measures the timing of the ink ejection operation performed by the recording section 9, and outputs the paper P toward the first conveying unit 5 (especially the first conveying belt 8 described later).

[0029] The paper P fed to the first conveying unit 5 by the registration roller pair 13 is conveyed by the first conveying belt 8 to a position facing the recording unit 9 (particularly, recording heads 17a to 17c described later). By ejecting ink from the recording unit 9 to the paper P, an image is recorded on the paper P. At this time, the ejection of ink in the recording unit 9 is controlled by the control device 110 inside the printer 100.

[0030] In the paper conveying direction, on the downstream side of the first conveying unit 5 ( Figure 1 On the left side of the sheet of paper 10, a second conveying unit 12 is provided. The sheet of paper P on which an image is recorded by the recording unit 9 is conveyed to the second conveying unit 12. The ink sprayed onto the surface of the sheet of paper P dries while passing through the second conveying unit 12.

[0031] A decurling unit 14 is provided downstream of the second conveying unit 12 in the paper conveying direction and near the left side of the printer body 1. The paper P dried by the second conveying unit 12 is conveyed to the decurling unit 14, and the curl generated in the paper P is corrected.

[0032] In the paper conveying direction, on the downstream side of the decurling section 14 ( Figure 1 ), a second paper conveying path 4b is provided above the de-curling unit 14. When double-sided recording is not performed, the paper P that has passed through the de-curling unit 14 is discharged to a paper discharge tray 15a through the second paper conveying path 4b. The paper discharge tray 15a is provided outside the left side of the printer 100. A secondary discharge tray 15b is provided below the paper discharge tray 15a, and the secondary discharge tray 15b discharges unnecessary paper P (damaged paper) that has a poor print or the like.

[0033] A reversing conveying path 16 for double-sided recording is provided at the upper portion of the printer body 1 and above the recording unit 9 and the second conveying unit 12. In the case of double-sided recording, the paper P that has been recorded on one side (first side) of the paper P and has passed through the second conveying unit 12 and the de-curling unit 14 passes through the second paper conveying path 4b and is conveyed to the reversing conveying path 16.

[0034] The paper P conveyed to the reversing conveying path 16 then switches its conveying direction for recording on the other side (second side) of the paper P. Then, the paper P passes through the upper part of the printer body 1 and is conveyed to the right side, passes through the registration roller pair 13, and is conveyed to the first conveying unit 5 again with the second side facing upward. In the first conveying unit 5, the paper P is conveyed to a position facing the recording unit 9, and an image is recorded on the second side by ejecting ink from the recording unit 9. The paper P after double-sided recording passes through the second conveying unit 12, the de-curling unit 14, and the second paper conveying path 4b in sequence, and is discharged to the paper discharge tray 15a.

[0035] In addition, a maintenance unit 19 and a cap unit 20 are arranged below the second conveying unit 12. When performing flushing, the maintenance unit 19 moves horizontally below the recording unit 9, wipes the ink extruded from the ink ejection port of the recording head, and recovers the wiped ink. In addition, flushing refers to the action of forcibly squeezing out the ink from the ink ejection port of the recording head in order to discharge the viscous ink, foreign matter, and bubbles in the ink ejection port. The cap unit 20 moves horizontally below the recording unit 9 when capping the ink ejection surface of the recording head, and then moves upward and is assembled on the lower surface of the recording head.

[0036] Figure 2 1 is a top view of the recording unit 9. The recording unit 9 includes a head cover 10 and line heads 11Y, 11M, 11C, and 11K. The line heads 11Y to 11K are held by the head cover 10 at a height that forms a predetermined interval (e.g., 1 mm) relative to the conveying surface of the endless first conveyor belt 8, wherein the first conveyor belt 8 is stretched over a driving roller 6a, a driven roller 6b, and tension rollers 7a and 7b (see FIG. Figure 3) of the plurality of rollers. The driving roller 6a causes the first conveyor belt 8 to move in the conveying direction (arrow A direction) of the paper P. The driving of the driving roller 6a is controlled by the main control unit 110a of the control device 110 (see Figure 4 ) control. In addition, the above-mentioned plurality of rollers are sequentially arranged along the traveling direction of the first conveyor belt 8: a tension roller 7a, a tension roller 7b, a driven roller 6b, and a driving roller 6a (refer to Figure 3 ).

[0037] Each of the line heads 11Y to 11K has a plurality of (three in this case) recording heads 17a to 17c. The recording heads 17a to 17c are arranged in a staggered manner along the paper width direction (arrow BB' direction) that is orthogonal to the paper conveying direction (arrow A direction). The recording heads 17a to 17c have a plurality of ink ejection ports 18 (nozzles). The ink ejection ports 18 are arranged at equal intervals along the width direction of the recording heads 17a to 17c, that is, the paper width direction (arrow BB' direction). Ink of yellow (Y), magenta (M), cyan (C), and black (K) is ejected from the line heads 11Y to 11K via the ink ejection ports 18 of the recording heads 17a to 17c toward the paper P conveyed by the first conveyor belt 8.

[0038] Inks of four colors (yellow, cyan, magenta, and black) stored in ink cartridges (not shown) are supplied to the recording heads 17 a to 17 c constituting the line heads 11Y to 11K, respectively, according to the colors of the line heads 11Y to 11K.

[0039] Each of the recording heads 17a to 17c is controlled by the control device 110 (see Figure 4 ), and according to the image data received from the external computer, ink is ejected from the ink ejection port 18 to the paper P which is held and transported by the first conveyor belt 8. Thus, a color image in which the four colors of ink, yellow, cyan, magenta and black, are superimposed is formed on the paper P on the first conveyor belt 8.

[0040] In order to clean the ink ejection surface of the recording heads 17a to 17c in the printer 100, at the start of printing after a long stop and in the interval of printing operation, the recovery operation of the recording heads 17a to 17c is performed, that is, the ink is squeezed out (flushed) from the ink ejection ports 18 of all the recording heads 17a to 17c, and the ink ejected to the ink ejection surface is wiped by a wiper (not shown) to prepare for the next printing operation. The ink wiped from the ink ejection surface F1 is used by the ink recovery units 31Y to 31K (see Figure 3 )Recycle.

[0041] Figure 3 The peripheral structure of the conveyance path of the paper P from the paper feed cassette 2 to the second conveyance unit 12 via the first conveyance unit 5 is schematically shown. Figure 41 is a block diagram showing the hardware configuration of the main parts of the printer 100. The printer 100 includes a registration sensor 21, a first paper sensor 22, a second paper sensor 23, and belt sensors 24 and 25 in addition to the above configuration.

[0042] The registration sensor 21 detects the paper P that is fed from the paper feed cassette 2 by the paper feed device 3 and sent to the registration roller pair 13. The registration sensor 21 is located on the upstream side of the registration roller pair 13 in the feeding direction of the paper P. The control device 110 (for example, the paper feeding control unit 110c) controls the rotation start timing of the registration roller pair 13 based on the detection result of the registration sensor 21. For example, the control device 110 controls the timing of feeding the paper P to the first conveyor belt 8 after the skew (skew) is corrected by the registration roller pair 13 based on the detection result of the registration sensor 21.

[0043] The first paper sensor 22 detects the position in the width direction of the paper P conveyed from the registration roller pair 13 to the first conveyor belt 8. The control device 110 (for example, the main control unit 110a) can eject ink from the ink ejection outlets 18 corresponding to the width of the paper P among the ink ejection outlets 18 of the recording heads 17a to 17c of the line heads 11Y to 11K based on the detection result of the first paper sensor 22, and record an image on the paper P.

[0044] The second paper sensor 23 detects the passage of the paper P supplied to the first conveyor belt 8 by the registration roller pair 13. That is, the second paper sensor 23 detects the position of the paper P conveyed by the first conveyor belt 8 in the conveying direction. The second paper sensor 23 is located on the upstream side of the recording unit 9 and on the downstream side of the first paper sensor 22 in the paper conveying direction. The control device 110 (for example, the main control unit 110a) can control the timing of ejecting ink to the paper P that reaches the position opposite to the line heads 11Y to 11K (recording heads 17a to 17c) by the first conveyor belt 8 based on the detection result of the second paper sensor 23.

[0045] The belt sensors 24 and 25 are reference detection sensors that detect a reference determination portion (not shown) provided on the first conveyor belt 8. The reference determination portion is a portion indicating a reference of one cycle of the first conveyor belt 8. Since the reference determination portion and the opening 80 (see FIG. 1 ) are known in advance, Figure 8 ), the reference determination portion of the first conveyor belt 8 can be detected by the belt sensors 24 and 25, and the position of each opening 80 (opening group 82) provided in the first conveyor belt 8 in the conveying direction can be detected based on the position of the detected reference determination portion. Therefore, the belt sensors 24 and 25 function as an opening position detection unit that detects the position of the opening 80 of the first conveyor belt 8.

[0046] Alternatively, marks may be formed in advance at positions corresponding to the opening groups 82 at the ends of the first conveyor belt 8 in the belt width direction, and the belt sensors 24 and 25 may detect the marks to detect the positions of the opening groups 82 (openings 80 ) corresponding to the marks.

[0047] The belt sensor 24 is located on the downstream side of the recording section 9 in the paper conveying direction (the traveling direction of the first conveyor belt 8). The belt sensor 25 is located on the upstream side of the paper conveying direction than the driven roller 6b that tensions the first conveyor belt 8. In the present embodiment, the belt sensor 25 is located between the driven roller 6b and the tension roller 7b, but it may also be located between the tension roller 7a and the tension roller 7b. The driven roller 6b is located on the upstream side of the traveling direction of the first conveyor belt 8 relative to the recording section 9. In addition, the belt sensor 24 has the same function as the second paper sensor 23. The control device 110 (for example, the paper supply control unit 110c) can control the registration roller pair 13 to supply the paper P to the first conveyor belt 8 at a predetermined time based on the detection result of the belt sensor 24 or 25.

[0048] Furthermore, since the position of the paper P is detected by multiple sensors (the first paper sensor 22 and the second paper sensor 23 ), and the reference determination portion of the first conveyor belt 8 is detected by multiple sensors (the belt sensors 24 and 25 ), error correction and abnormality detection of the detection position can also be performed.

[0049] The first paper sensor 22 , the second paper sensor 23 , and the belt sensors 24 and 25 may be formed of a transmissive or reflective optical sensor, a CIS sensor (Contact Image Sensor), or the like.

[0050] Furthermore, the printer 100 may be configured to include a fluctuation advance detection sensor for detecting the fluctuation advance of the first conveyor belt 8 , and to correct the fluctuation advance of the first conveyor belt 8 based on the detection result.

[0051] The printer 100 also includes an operation panel 27 , a storage unit 28 , and a communication unit 29 .

[0052] The operation panel 27 is an operation unit for receiving various setting inputs. For example, the user can operate the operation panel 27 to input the size of the paper P placed in the paper feed cassette 2, that is, the size information of the paper P conveyed by the first conveyor belt 8. In addition, the user can also operate the operation panel 27 to input the number of sheets of paper P to be printed or to instruct the start of a printing job. In addition, the operation panel 27 also has a function as a notification device, that is, it can make notifications related to the operating status of the printer 100 (image recording, flushing described later).

[0053] The storage unit 28 is a memory that stores the operating program of the control device 110 and various information, and is configured to include a ROM (Read Only Memory), a RAM (Random Access Memory), a nonvolatile memory, etc. Information set through the operation panel 27 (for example, information on the size and number of sheets of paper P) is stored in the storage unit 28 .

[0054] The communication unit 29 is a communication interface for transmitting and receiving information with an external device (such as a personal computer (PC)). For example, when a user operates the PC to send image data and a printing command to the printer 100, the image data and the printing command are input to the printer 100 via the communication unit 29. In the printer 100, the main control unit 110a can control the recording heads 17a to 17c to eject ink based on the image data, thereby recording an image on the paper P.

[0055] In addition, the printer 100 of the present embodiment includes a control device 110. The control device 110 is configured to include, for example, a CPU (Central Processing Unit) and a memory. Specifically, the control device 110 includes a main control unit 110a, a flushing control unit 110b, a paper supply control unit 110c, and a maintenance control unit 110d. Each control unit constituting the control device 110 is composed of one CPU, but may also be composed of different CPUs.

[0056] The main control unit 110 a controls the operation of each unit of the printer 100. For example, the main control unit 110 a controls the driving of each roller inside the printer 100 and the ejection of ink from the recording heads 17 a to 17 c during image formation (except during flushing).

[0057] The flushing control unit 110 b causes the recording heads 17 a to 17 c to execute flushing based on the position detection of the opening 80 by the belt sensor 24 or 25 .

[0058] The paper supply control unit 110c is a recording medium supply control unit that controls the registration roller pair 13 as a recording medium supply unit. For example, the paper supply control unit 110c controls the registration roller pair 13 based on the position detection of the opening 80 by the belt sensor 24 or 25. In addition, the paper supply control unit 110c can also control the registration roller pair 13 in a manner independent of the position detection of the opening 80 by the belt sensor 24 or 25 (regardless of the position detection).

[0059] The maintenance control unit 110d controls the recording heads 17a to 17c to perform the above-mentioned flushing for forcibly squeezing out the ink from the ink ejection ports 18. When the maintenance control unit 110d causes the recording heads 17a to 17c to perform the flushing, it also controls the driving of the above-mentioned maintenance unit 19 (for example, movement to the bottom of the recording unit 9 and retreat).

[0060] In addition, if Figure 3 As shown, the printer 100 has ink recovery units 31Y, 31M, 31C, and 31K on the inner peripheral surface side of the first conveyor belt 8. When the recording heads 17a to 17c are flushed, the ink recovery units 31Y to 31K receive and recover the ink ejected from the recording heads 17a to 17c and passing through the opening 80 of the first conveyor belt 8. Therefore, the ink recovery units 31Y to 31K are provided at positions opposite to the recording heads 17a to 17c of the line heads 11Y to 11K across the first conveyor belt 8.

[0061] The second conveying unit 12 includes a second conveying belt 12a and a dryer 12b. The second conveying belt 12a is stretched by two rollers, namely, a driving roller 12c and a driven roller 12d. The paper P conveyed by the first conveying unit 5 and having an image recorded thereon by the inkjet of the recording unit 9 is conveyed by the second conveying belt 12a, dried by the dryer 12b during the conveying process, and conveyed to the above-mentioned unwinding unit 14.

[0062] (2. Details of the ink recovery department)

[0063] Next, the configuration of the ink recovery units 31Y to 31K will be described in detail. Figure 5 31Y and the paper conveying area adjacent to the ink recovery unit 31Y. Figure 5 In the figure, the description of the first conveyor belt 8 is omitted. Hereinafter, the structure of the ink recovery unit 31Y and its surroundings will be described, but the ink recovery units 31M to 31K also have the same structure, and thus the description thereof will be omitted.

[0064] The ink recovery unit 31Y is disposed between the pair of side frames 100 a so as to be aligned with the recording heads 17 a to 17 c (see FIG. 1 ) constituting the line head 11Y. Figure 2 ) are opposite. Ink receiving portions 32a to 32c for receiving ink droplets ejected from the recording heads 17a to 17c are provided on the upper surface of the ink recovery portion 31Y.

[0065] The suction fan 40 as the suction unit is installed at two locations of the side frame 100a and connected to one end of the suction duct 37. A plurality of suction ports 41 are provided at the other end of the suction duct 37. The suction ports 41 are connected to the first conveyor belt 8 (see Figure 3) are disposed opposite to the inner circumference of the first conveyor belt 8. A plurality of suction holes 8a for air suction are provided on the first conveyor belt 8 (refer to Figure 8 ). By operating the suction fan 40, air on the outer peripheral surface side of the first conveyor belt 8 is sucked through the suction hole 8a. More specifically, the paper suction area R (excluding the ink receiving parts 32a to 32c) is sucked. Figure 5 According to this structure, the paper P is sucked onto the conveying surface of the first conveying belt 8 by the suction wind generated in the paper suction area R and conveyed.

[0066] Figure 6 is a side cross-sectional view of the ink recovery unit 31Y cut along a direction perpendicular to the conveying direction ( Figure 5 CC′ section view). Figure 7 2 is a plan cross-sectional view of the waste ink tank 33 constituting the ink recovery unit 31Y. The waste ink tank 33 is disposed below the ink receiving units 32a to 32c. A suction path 35 and an ink recovery path 36 are provided inside the waste ink tank 33.

[0067] The suction path 35 is formed of, for example, a resin material, and includes: a first flow path 35a, a confluence chamber 35b, and a second flow path 35c. The first flow path 35a is connected to the ink receiving parts 32a to 32c. The confluence chamber 35b is used to merge the three first flow paths 35a connected to the ink receiving parts 32a to 32c into one place. The upper end of the second flow path 35c is connected to the confluence chamber 35b, and the lower end of the second flow path 35c opens in the duct 37. According to the above structure, the ink receiving parts 32a to 32c are connected to the suction fan 40 via the suction path 35 and the duct 37.

[0068] Ink droplets contained in the air flow passing through the suction path 35 contact the inner wall surfaces of the first flow path 35a and the merging chamber 35b and remain below. The ink remaining below the waste ink tank 33 is discharged to the outside through the ink recovery path 36.

[0069] The ink recovery path 36 includes an inclined portion 36a and an ink discharge pipe 36b. The inclined portion 36a is formed adjacent to the first flow path 35a and the confluence chamber 35b below, and the ink discharge pipe 36b is connected to the lowest part (bottom) of the inclined portion 36a. Ink droplets attached to the inner wall surfaces of the first flow path 35a and the confluence chamber 35b flow downward along the inner wall surfaces, and then flow along the inclined portion 36a and gather at one place (the lowest part). Ink droplets are recovered to a waste ink recovery bottle (not shown) through the ink discharge pipe 36b.

[0070] In addition, although the ink recovery path 36 for recovering the ink retained in the waste ink tank 33 is provided here, an ink absorber such as melamine sponge may be arranged in the waste ink tank 33 instead of the ink recovery path 36. In this case, the ink absorbed by the ink absorber is stored in the waste ink tank 33 and is discarded or recovered when the waste ink tank 33 is replaced.

[0071] (3. Details of the first conveyor belt)

[0072] Next, the first conveyor belt 8 of the first conveyor unit 5 will be described in detail. Figure 8 This is a partially enlarged view of the periphery of the opening portion group 82 of the first conveyor belt 8 used in the printer 100 according to the first embodiment of the present invention.

[0073] In this embodiment, a negative pressure suction method is adopted, that is, the paper P is sucked to the first conveyor belt 8 for conveyance by the negative pressure suction of the suction fan 40. Therefore, a plurality of suction holes 8a are formed throughout the first conveyor belt 8, and the air flow (suction wind) for sucking the paper P to the first conveyor belt 8 by negative pressure suction passes through the suction holes 8a.

[0074] The first conveyor belt 8 has a plurality of openings 80, and the openings 80 allow the ink ejected from the nozzles (ink ejection ports 18) of the recording heads 17a to 17c to pass through when flushing is performed. In the present embodiment, an opening group 82 composed of a plurality of openings 80 is formed in a straight line over the entire width direction of the first conveyor belt 8. The openings 80 include: an opening located on the upstream side (in the direction of arrow A) relative to the conveying direction of the first conveyor belt 8; Figure 8 A row of upstream side openings 81) on the lower side.

[0075] In this embodiment, the shape of each opening 80 when viewed from above is as follows: Figure 8 The holes shown are circular, but may also be rectangular or may be elongated in the belt width direction (arrow BB′ direction) (e.g., elliptical). In addition, the number of openings 80 in one row may be the same as the number of openings 80 in another row (most upstream openings 81).

[0076] Will Figure 8 The opening section group 82 shown is formed as a group, and a plurality of opening section groups 82 are formed in one cycle of the first conveyor belt 8. The intervals of the groups of opening section groups 82 in the conveying direction are different, and they are formed irregularly at positions corresponding to the size of the paper P to be conveyed. That is, the intervals between two adjacent opening section groups 82 in the paper conveying direction are not constant, but different. At this time, the maximum interval between the two adjacent opening section groups 82 in the paper conveying direction is longer than the length of the paper P in the paper conveying direction when the paper P of the minimum size that can be printed (for example, A4 size horizontally) is placed on the first conveyor belt 8.

[0077] An air circulation hole 83 is formed immediately upstream of the opening group 82 with respect to the conveying direction (arrow A direction) of the first conveyor belt 8. A plurality of air circulation holes 83 are formed over substantially the entire width direction of the first conveyor belt 8. More specifically, the air circulation holes 83 are formed in the same number and interval as the most upstream opening 81.

[0078] Fig. 9 FIG. 8 is a top view showing the positional relationship between the opening group 82 of the first conveyor belt 8 and the ink receiving portions 32a to 32c. Fig. 9 As shown, when the first conveyor belt 8 moves in the conveying direction (arrow A direction) and the opening group 82 overlaps with the ink receiving portion 32a, 32c, the recording head 17a, 17c performs flushing. Fig. 9 When the opening group 82 overlaps with the ink receiving portion 32b and further moves in the conveying direction from the state of the recording head 17a to 17c, the recording head 17b performs flushing. The ink ejected from each ink ejection port 18 of the recording heads 17a to 17c passes through any opening 80 of the opening group 82. Therefore, the recording heads 17a to 17c can be flushed over the entire head width, so that all the ink ejection ports 18 are less clogged due to ink drying.

[0079] (4. Suction-assisting function of air circulation holes)

[0080] Next, the suction assisting function of the air circulation holes 83 , which is a characteristic feature of the printer 100 of the present embodiment, will be described. Fig.10 This is a side cross-sectional view showing a state in which the most upstream opening 81 of the first conveyor belt 8 passes through the ink receiving portions 32 a to 32 c in the printer 100 according to the first embodiment. Fig.11 It is a plan view of the vicinity of the most upstream opening 81 of the first conveyor belt 8 , and shows the positional relationship between the most upstream opening 81 and the air circulation holes 83 .

[0081] like Fig.10 As shown in FIG. 1 , a belt support plate 60 is disposed between the first conveyor belt 8 and the ink receiving parts 32a to 32c. The belt support plate 60 is disposed opposite to the inner circumference of the first conveyor belt 8 and supports the first conveyor belt 8 from the inside. There is no belt support plate 60 below the recording heads 17a to 17c, and an ink passage 60a is formed between the recording heads 17a to 17c and the ink receiving parts 32a to 32c. The ink passage 60a also functions as a duct, which is supplied by the suction fan 40 (see FIG. 1 ). Figure 5 ) passes through the suction wind generated by the recording heads 17a to 17c for sucking the ink droplets In ejected from the recording heads 17a to 17c.

[0082] The ink receiving parts 32a to 32c are filled with an ink absorber 61. The ink absorber 61 is formed of a porous material such as sponge. The upper surface of the ink absorber 61 serves as a contact surface F with ink droplets.

[0083] When the uppermost opening 81 of the opening group 82 of the first conveyor belt 8 passes through the ink passage 60a, the upper portion of the ink passage 60a is blocked by the first conveyor belt 8, and the suction fan 40 cannot suck the air in the ink passage 60a. Therefore, the ink droplets cannot be sucked together with the suction wind and recovered to the ink receiving parts 32a to 32c, and the atomized ink droplets are retained in the ink passage 60a.

[0084] In addition, as the first conveyor belt 8 moves, the airflow approaches the first conveyor belt 8 from the front side and the back side of the first conveyor belt 8, and the airflow is turned upside down and turbulent. Under the influence of the airflow, the mist-like ink droplets retained in the ink passage 60a adhere to the back side of the first conveyor belt 8 and accumulate. As a result, the entire interior of the printer 100 is contaminated.

[0085] Therefore, in the present embodiment, an air circulation hole 83 is formed immediately upstream of the most upstream opening 81 with respect to the conveying direction (arrow A direction) of the first conveyor belt 8. Thus, even after the most upstream opening 81 passes through the upper portion of the ink passage 60a, the air circulation hole 83 is used to maintain the state in which the inside and the outside of the ink passage 60a are connected. Therefore, the ink droplets In can be sucked together with the suction wind, and the ink droplets In can be reliably recovered by contacting the contact surfaces F of the ink receiving portions 32a to 32c.

[0086] Therefore, the ink will not accumulate in the ink passage 60a, but can be reliably recovered to the ink receiving parts 32a to 32c, thereby suppressing contamination of the back side of the first conveyor belt 8 and internal contamination of the printer 100, and maintaining image quality through flushing.

[0087] Next, the size, shape, number, and formation position of the air circulation hole 83 are described. In the present embodiment, a circular air circulation hole 83 having a smaller diameter than the opening 80 (the most upstream opening 81) is formed, but there is no particular limitation on the size and shape of the air circulation hole 83. For example, an air circulation hole 83 in the shape of a long hole extending in the belt width direction may be formed. However, if the air circulation hole 83 becomes larger, the strength of the first conveyor belt 8 will decrease. Therefore, as long as the air in the ink passage 60a can be sucked, it is preferred that the air circulation hole 83 is as small as possible.

[0088] In addition, there is no particular limitation on the number and intervals of the air circulation holes 83. For example, when the air circulation holes 83 are formed at three locations, namely, the center and both ends in the tape width direction, the intervals between the plurality of most upstream openings 81 and the air circulation holes 83 are different. Therefore, the airflow passing through the air circulation holes 83 has different effects on each of the most upstream openings 81, and the following problem may occur: the ink droplets passing through the most upstream openings 81 that are more affected by the airflow may be offset from contact.

[0089] Therefore, as in the present embodiment, the air circulation holes 83 are formed in the same number and interval as the most upstream openings 81, so that the influence of the airflow passing through the air circulation holes 83 is constant at each most upstream opening 81. Thus, the contact deviation of the ink droplets passing through the most upstream opening 81 can be suppressed.

[0090] In addition, if Fig.11 As shown, the interval d1 between the most upstream opening 81 and the air circulation hole 83 in the conveying direction (arrow A direction) of the first conveyor belt 8 needs to be smaller than the width w of the ink passage 60a in the conveying direction. According to this structure, after the most upstream opening 81 passes through the ink passage 60a, the air circulation hole 83 overlaps with the upper part of the ink passage 60a, so that the suction assisting effect of the air circulation hole 83 can be ensured.

[0091] Fig.12 It is a plan view of the periphery of the opening portion group 82 of the first conveyor belt 8 included in the printer 100 according to the second embodiment of the present invention. Fig.13 This is a side cross-sectional view showing a state in which the most upstream opening 81 of the first conveyor belt 8 passes through the ink receiving portions 32 a to 32 c in the printer 100 according to the second embodiment. Fig.14 It is a plan view of the vicinity of the most upstream opening 81 of the first conveyor belt 8 of the printer 100 according to the second embodiment, and shows the positional relationship between the most upstream opening 81 and the suction hole 8 a.

[0092] like Fig.12 As shown, in this embodiment, no air circulation hole 83 is formed on the first conveyor belt 8, but with respect to the conveying direction (arrow A direction) of the first conveyor belt 8, the upstream side ( Fig.12 That is, the suction hole 8a on the upstream side of the opening portion group 82 also serves as the air circulation hole 83.

[0093] Therefore, if Fig.13As shown, after the most upstream opening 81 passes through the upper part of the ink passage 60a, the suction hole 8a is also used to maintain the state in which the inside and the outside of the ink passage 60a are connected. Therefore, as in the first embodiment, the ink droplets In can be sucked together with the suction wind, and the ink droplets In can be made to contact the contact surfaces F of the ink receiving parts 32a to 32c and be reliably recovered.

[0094] In addition, if Fig.14 As shown, the interval d2 between the most upstream opening 81 and the suction hole 8a in the conveying direction (arrow A direction) of the first conveyor belt 8 needs to be smaller than the width w of the ink passage 60a in the conveying direction. According to this structure, after the most upstream opening 81 passes through the ink passage 60a, the suction hole 8a overlaps with the upper part of the ink passage 60a, so that the suction assisting function of the suction hole 8a can be ensured.

[0095] (5. Others)

[0096] The present invention is not limited to the above-mentioned embodiments, and various changes can be made without departing from the scope of the present invention. For example, in the above-mentioned embodiment, a structure in which three recording heads 17a to 17c are arranged in a staggered manner for each color of the line heads 11Y to 11K is described, but the present invention is not limited to this structure. For example, the present invention can also be applied to a structure in which the recording heads 17a to 17c constituting the line heads 11Y to 11K are arranged in a straight line.

[0097] In addition, in the above-mentioned embodiments, the structure of using the first conveyor belt 8 in which the opening portion group 82 composed of a plurality of opening portions 80 is irregularly arranged at positions corresponding to the paper size in the conveying direction is described, but it is also possible to use the first conveyor belt 8 in which the group of opening portion groups 82 is arranged at constant intervals in the paper conveying direction.

[0098] In addition, in the above-mentioned embodiments, in order to ensure the strength of the first conveyor belt 8, a plurality of small-diameter openings 80 are provided on the first conveyor belt 8, thereby covering the entire width-direction ejection range of the recording heads 17a to 17c, but the present invention is not limited to this structure. For example, according to the structure of the printer 100, as long as the strength of the first conveyor belt 8 can be ensured by supporting it with the belt support plate 60, it is also possible to use a single opening 80 that is elongated in the width direction to cover the entire width-direction ejection range of the recording heads 17a to 17c. In this case, it is sufficient to form an air circulation hole 83 on the upstream side of the single opening 80, and to make the interval between the opening 80 and the air circulation hole 83 smaller than the width of the ink passage 60a in the conveying direction.

[0099] In addition, in the above-mentioned embodiments, the case where the paper P is adsorbed to the first conveyor belt 8 by negative pressure suction for conveyance is described, but the first conveyor belt 8 may be charged so that the paper P is electrostatically adsorbed to the first conveyor belt 8 for conveyance (electrostatic adsorption method). For example, in the first embodiment, when the paper P is electrostatically adsorbed, the suction hole 8a of the first conveyor belt 8 is not required.

[0100] In the above-described embodiments, a color printer that records color images using four-color inks is described as an inkjet recording apparatus, but the present invention is also applicable to a monochrome printer that records monochrome images using black ink.

[0101] The present invention can be used in inkjet recording devices such as inkjet printers.

Claims

1. An inkjet recording device comprising: a recording head having a plurality of nozzles for ejecting ink; a conveying member having an opening through which the ink ejected from the recording head passes and conveying a recording medium; a control unit that controls the driving of the recording head and the conveying member to perform flushing at a timing different from a timing that contributes to image recording, that is, to cause the ink to be ejected from the nozzle of the recording head and pass through the opening; an ink recovery unit including an ink receiving unit disposed opposite to the recording head with the transport member interposed therebetween and receiving the ink passing through the opening when the flushing is performed; an ink passage formed between the conveying member and the ink receiving portion and through which the ink passing through the opening portion passes; and a suction portion connected to the ink receiving portion and sucking air in the ink passage and the ink passing through the opening, The inkjet recording device is characterized in that The conveying member has an air circulation hole formed on the upstream side of the opening with respect to the conveying direction. A distance between the opening in the conveying direction and the air circulation hole is smaller than a width of the ink passage in the conveying direction.

2. The inkjet recording device according to claim 1, characterized in that The conveying member is provided with one or more opening groups, the opening group being composed of a plurality of openings arranged in a conveying direction of the recording medium and in a width direction orthogonal to the conveying direction, the opening group including an upstream-most opening located on an upstream side relative to the conveying direction, A distance between the most upstream opening in the conveying direction and the air circulation hole is smaller than a width of the ink passage in the conveying direction.

3. The inkjet recording device according to claim 1, characterized in that The opening is formed in plurality at predetermined intervals in the width direction. The air circulation holes are formed in the same number and at the same intervals as the openings.

4. The inkjet recording device according to claim 1, characterized in that The conveying member is formed with a plurality of suction holes, through which air flows for sucking the recording medium to the conveying member by negative pressure. The suction hole formed immediately upstream of the opening with respect to the conveying direction also serves as the air circulation hole.

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