Inkjet recording device

Abstract

To provide an inkjet recording device that can suppress contamination of a transport belt during flushing and suppress the lifting of a recording medium during image recording.SOLUTION: An inkjet recording device includes a recording head, a transport member, a control part, an ink collection part, an ink passage, a suction part, a shutter, and a shutter drive part. The shutter overlaps a part of the ink passage in the transport direction of the recording medium and is capable of reciprocating along the transport direction between the upstream side and the downstream side of the ink passage. The control part controls the shutter drive part so that the shutter is positioned at the center of the ink passage in the transport direction during flushing. During image recording, when the tip and rear end of the recording medium pass through the ink passage, the shutter is moved from the upstream side to the downstream side of the ink passage along with the transport of the recording medium such that the shutter is positioned immediately downstream of the tip and rear end of the recording medium with respect to the transport direction.SELECTED DRAWING: Figure 10

Description

[Technical field]

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

[0002] Conventionally, in inkjet recording devices such as inkjet printers, flushing (empty ejection) is performed periodically to eject ink from the nozzles in order to reduce or prevent clogging of the nozzles due to drying of the ink. For example, in the inkjet recording device of Patent Document 1, an opening is provided in a conveyor belt that conveys the recording medium, and ink is ejected from each nozzle of the recording head to pass through the opening of the conveyor belt.

[0003] In the inkjet recording device described above, the ink droplets that have passed through the openings in the transport belt by flushing reach an ink receiving section that normally receives ink, are collected, and are discharged from the ink receiving section as waste liquid. If the ink receiving section could be located near the ink ejection surface of the recording head, almost all of the ink droplets could be collected by the ink receiving section. However, since the transport belt is located between the recording head and the ink receiving section, it is difficult to locate the ink receiving section near the ink ejection surface. As a result, the ink droplets turn into mist before reaching the ink receiving section, contaminating the inside of the device.

[0004] As a method for improving the recovery of ejected ink droplets, a configuration is known in which the ink receiving section is subjected to negative pressure suction to recover the ink droplets together with air. For example, Patent Document 1 discloses an inkjet recording device having a shutter member that opens the gap between the ink receiving section and the side of the conveyor belt opposite the paper conveying surface during flushing, and reduces the flow of air between the ink receiving section and the side of the conveyor belt opposite the paper conveying surface during recording, compared to the open state. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2022-143671 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the method of Patent Document 1, if the ink ejected during flushing turns into mist and scatters, it may fly up due to the negative suction pressure used to collect it, adhere to the nozzle surface of the recording head, and cause ejection failure. Also, because the negative suction pressure directly below the recording head weakens during image recording, the leading or trailing edge of the paper may lift up as it passes the recording head, colliding with the nozzle surface of the recording head and causing image defects.

[0007] In view of the above problems, the present invention aims to provide an inkjet recording device that has a configuration in which an ink receiving section is sucked with negative pressure, which can suppress contamination of the transport belt during flushing and can suppress the floating of the recording medium during image recording. [Means for solving the problem]

[0008] In order to achieve the above object, a first configuration of the present invention is an inkjet recording device including a recording head, a conveying member, a control unit, an ink recovery unit, an ink passage, a suction unit, a shutter, and a shutter drive unit. The recording head has a plurality of nozzles that eject ink. The conveying member has a plurality of openings through which ink ejected from the recording head passes, and conveys the recording medium. The control unit controls the driving of the recording head and the conveying member to perform flushing, in which ink is ejected from the nozzles of the recording head at a timing different from the timing contributing to image recording, and passes through one of the plurality of openings. The ink recovery unit is disposed opposite the recording head across the conveying member, and has an ink receiving unit that receives ink that has passed through the openings during flushing. The ink passage is formed between the conveying member and the ink receiving unit, and the ink that has passed through the openings passes through the ink passage. The suction unit is connected to the ink receiving unit, and sucks the ink that has passed through the openings together with the air in the ink passage. The shutter overlaps a part of the ink passage in the conveying direction of the recording medium, and is capable of reciprocating along the conveying direction between the upstream side and the downstream side of the ink passage. The shutter drive unit drives the shutter. The control unit controls the shutter drive unit to position the shutter in the center of the ink passage in the transport direction when flushing is performed. When the leading and trailing ends of the recording medium are passing through the ink passage during image recording, the shutter is moved from the upstream side to the downstream side of the ink passage in accordance with the transport of the recording medium so that the shutter is located immediately downstream of the leading and trailing ends of the recording medium in the transport direction. Effect of the Invention

[0009] According to the first configuration of the present invention, by covering the center of the ink passage with the shutter during flushing, it is possible to suppress the floating up of mist-like ink droplets and efficiently collect the ink droplets. Also, by moving the shutter in accordance with the passage of the leading and trailing ends of the recording medium during image recording, it is possible to increase the suction negative pressure at the leading and trailing ends of the recording medium and suppress contact of the recording medium with the nozzle face of the recording head. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is an explanatory diagram showing a schematic configuration of a printer 100 as an inkjet recording apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a plan view of a recording unit 9 included in a printer 100 according to an embodiment of the present invention. [Diagram 3] FIG. 1 is an explanatory diagram showing a schematic configuration of the vicinity of a paper transport path from a paper feed cassette 2 to a second transport unit 12 via a first transport unit 5 of a printer 100 according to an embodiment of the present invention; [Figure 4] FIG. 1 is a block diagram showing the hardware configuration of the main part of a printer 100 according to an embodiment of the present invention. [Diagram 5] FIG. 13 is a schematic diagram showing the ink recovery unit 31Y and a paper transport area adjacent to the ink recovery unit. [Figure 6] FIG. 1 is a side cross-sectional view of the ink recovery unit 31Y taken along a direction perpendicular to the transport direction. [Figure 7] A plan sectional view of the waste ink tank 33 constituting the ink recovery unit 31Y. [Figure 8] A partially enlarged view of the periphery of the opening group 82 of the first conveyor belt 8 used in the printer 100. [Figure 9] A partially enlarged view of the ink passage 60a and its surroundings of the belt support plate 60 used in the printer 100. [Figure 10] FIG. 11 is a plan view showing the arrangement of the shutter 70 of the ink passage 60a when flushing is performed. [Figure 11] FIG. 13 is a side cross-sectional view showing the arrangement of the shutter 70 of the ink passage 60a when flushing is performed. [Figure 12] FIG. 1 is a side view of the shutter 70 as seen from one end in the width direction. [Figure 13] FIG. 1 is a plan view showing the arrangement of the shutter 70 immediately before the leading edge of the paper P passes through the ink passage 60a during image recording. [Figure 14] FIG. 13 is a side cross-sectional view showing the arrangement of the shutter 70 just before the leading edge of the paper P passes through the ink passage 60a. [Figure 15] FIG. 11 is a plan view showing the operation of the shutter 70 when the leading edge of the paper P is passing through the ink passage 60a. [Figure 16] FIG. 11 is a side cross-sectional view showing the operation of the shutter 70 when the leading edge of the paper P is passing through the ink passage 60a. [Figure 17] FIG. 11 is a plan view showing the arrangement of the shutter 70 after the leading edge of the paper P has passed through the ink passage 60a. [Figure 18] FIG. 13 is a side cross-sectional view showing the arrangement of the shutter 70 after the leading edge of the paper P has passed through the ink passage 60a. [Figure 19] FIG. 11 is a plan view showing the operation of the shutter 70 when the rear end of the paper P is passing through the ink passage 60a. [Figure 20] FIG. 11 is a side cross-sectional view showing the operation of the shutter 70 when the rear end of the paper P is passing through the ink passage 60a. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] 1. Configuration of the Inkjet Recording Apparatus Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is an explanatory diagram showing the general configuration of a printer 100 as an inkjet recording device according to one embodiment of the present invention. The printer 100 is equipped with a paper feed cassette 2 which is a paper storage section. The paper feed cassette 2 is located at the bottom inside the printer main body 1. Inside the paper feed cassette 2, paper P, which is an example of a recording medium, is stored.

[0012] A paper feeder 3 is disposed downstream of the paper feed cassette 2 in the paper transport direction, i.e., above the right side of the paper feed cassette 2 in Fig. 1. The paper feeder 3 separates and sends out the paper P one by one toward the upper right of the paper feed cassette 2 in Fig. 1.

[0013] The printer 100 has a first paper transport path 4a inside. The first paper transport path 4a is located in the upper right corner, which is the paper feed direction, of the paper feed cassette 2. The paper P sent out from the paper feed cassette 2 is transported vertically upward along the side of the printer body 1 by the first paper transport path 4a.

[0014] A pair of registration rollers 13 is provided at the downstream end of the first paper transport path 4a in the paper transport direction. Furthermore, a first transport unit 5 and a recording unit 9 are arranged immediately downstream in the paper transport direction of the pair of registration rollers 13. The paper P sent out from the paper feed cassette 2 reaches the pair of registration rollers 13 through the first paper transport path 4a. The pair of registration rollers 13 corrects skewed feed of the paper P and sends the paper P toward the first transport unit 5 (particularly the first transport belt 8 described later) in time with the ink ejection operation performed by the recording unit 9.

[0015] The paper P sent to the first transport unit 5 by the registration roller pair 13 is transported by the first transport belt 8 to a position facing the recording unit 9 (particularly recording heads 17a to 17c described below). An image is recorded on the paper P by ejecting ink from the recording unit 9 onto the paper P. At this time, the ejection of ink in the recording unit 9 is controlled by a control device 110 inside the printer 100.

[0016] In the paper transport direction, a second transport unit 12 is disposed downstream of the first transport unit 5 (on the left side in FIG. 1). The paper P on which an image has been recorded by the recording unit 9 is sent to the second transport unit 12. The ink ejected onto the surface of the paper P is dried while passing through the second transport unit 12.

[0017] In the paper transport direction, a decurler unit 14 is provided downstream of the second transport unit 12 and near the left side surface of the printer body 1. The paper P from which the ink has been dried by the second transport unit 12 is sent to the decurler unit 14, where any curls in the paper P are straightened out.

[0018] In the paper transport direction, a second paper transport path 4b is provided downstream of the decurler unit 14 (upper in FIG. 1). If double-sided recording is not performed, the paper P that has passed through the decurler unit 14 passes through the second paper transport path 4b and is discharged to a paper discharge tray 15a provided outside the left side of the printer 100. A sub-discharge tray 15b is provided below the paper discharge tray 15a to discharge unnecessary paper P (broken paper) that has experienced printing defects or the like.

[0019] A reversing transport path 16 for double-sided recording is provided at the top of the printer body 1, above the recording unit 9 and the second transport unit 12. When double-sided recording is performed, after recording on one side (first side) of the paper P is completed and the paper P passes through the second transport unit 12 and the decurler unit 14, it is sent to the reversing transport path 16 via the second paper transport path 4b.

[0020] After being sent to the reversing transport path 16, the transport direction of the paper P is then switched so that recording can be performed on the other side (second side) of the paper P. The paper P then passes over the top of the printer body 1 and is transported to the right side, passes through the pair of registration rollers 13, and is sent again to the first transport unit 5 with the second side facing up. In the first transport unit 5, the paper P is transported to a position facing the recording section 9, and an image is recorded on the second side by ink ejection from the recording section 9. After double-sided recording, the paper P passes through the second transport unit 12, the decurler section 14, and the second paper transport path 4b in that order, and is discharged to the paper discharge tray 15a.

[0021] In addition, a maintenance unit 19 and a cap unit 20 are disposed below the second transport unit 12. The maintenance unit 19 moves horizontally below the recording unit 9 when performing purging, wipes off ink extruded from the ink ejection ports of the recording head, and collects the wiped ink. Purging refers to the operation of forcibly pushing out ink from the ink ejection ports of the recording head in order to expel thickened ink, foreign matter, and air bubbles from the ink ejection ports. The cap unit 20 moves horizontally below the recording unit 9 when capping the ink ejection surface of the recording head, and then moves further upward to be attached to the underside of the recording head.

[0022] FIG. 2 is a plan view of the recording unit 9. The recording unit 9 includes a head housing 10 and line heads 11Y, 11M, 11C, and 11K. The line heads 11Y to 11K are held in the head housing 10 at a height that forms a predetermined gap (for example, 1 mm) with respect to the conveying surface of the endless first conveyor belt 8 that is stretched around a plurality of rollers including a driving roller 6a, a driven roller 6b, and tension rollers 7a and 7b (see FIG. 3). The driving roller 6a drives the first conveyor belt 8 in the conveying direction of the paper P (the direction of the arrow A). The driving of the driving roller 6a is controlled by a main control unit 110a of the control device 110 (see FIG. 4). The above-mentioned plurality of rollers are arranged in the following order along the running direction of the first conveyor belt 8: tension roller 7a, tension roller 7b, driven roller 6b, and driving roller 6a (see FIG. 3).

[0023] Each of the line heads 11Y to 11K has a plurality of (three in this example) recording heads 17a to 17c. The recording heads 17a to 17c are arranged in a staggered pattern along the paper width direction (arrow BB' direction) perpendicular to the paper transport direction (arrow A direction). The recording heads 17a to 17c have a plurality of ink ejection openings 18 (nozzles). The ink ejection openings 18 are arranged at equal intervals in the width direction of the recording head, that is, the paper width direction (arrow BB' direction). From the line heads 11Y to 11K, inks of yellow (Y), magenta (M), cyan (C), and black (K) are ejected toward the paper P transported by the first transport belt 8 through the ink ejection openings 18 of the recording heads 17a to 17c.

[0024] To the recording heads 17a to 17c constituting each of the line heads 11Y to 11K, ink of four colors (yellow, cyan, magenta, and black) stored in ink tanks (not shown) is supplied for each of the line heads 11Y to 11K.

[0025] Each of the recording heads 17a to 17c ejects ink from the ink ejection orifices 18 toward the paper P that is adsorbed and held on the conveying surface of the first conveyor belt 8 and conveyed in accordance with image data received from an external computer by a control signal from the control device 110 (see FIG. 4). As a result, a color image is formed on the paper P on the first conveyor belt 8 by overlapping four colors of ink: yellow, cyan, magenta, and black.

[0026] In the printer 100, in order to clean the ink ejection surfaces of the recording heads 17a to 17c, when printing starts after a long period of inactivity and between printing operations, ink is extruded (purged) from the ink ejection ports 18 of all of the recording heads 17a to 17c, and a recovery operation of the recording heads 17a to 17c is performed in which the ink ejected on the ink ejection surfaces is wiped off with a wiper (not shown) in preparation for the next printing operation. The ink wiped off from the ink ejection surface F1 is collected by ink recovery units 31Y to 31K (see FIG. 3), which will be described later.

[0027] Fig. 3 shows a schematic configuration of the vicinity of the transport path of the paper P from the paper feed cassette 2 to the second transport unit 12 via the first transport unit 5. Fig. 4 is a block diagram showing the hardware configuration of the main parts of the printer 100. In addition to the above configuration, the printer 100 further includes a registration sensor 21, a first paper sensor 22, a second paper sensor 23, and belt sensors 24 and 25.

[0028] The registration sensor 21 detects the paper P transported by the paper feeder 3 from the paper cassette 2 and sent to the registration roller pair 13. The registration sensor 21 is located upstream of the registration roller pair 13 in the supply direction of the paper P. The control device 110 (e.g., paper supply control unit 110c) controls the timing at which the registration roller pair 13 starts to rotate based on the detection result of the registration sensor 21. For example, the control device 110 controls the timing at which the paper P is supplied to the first transport belt 8 after skew (oblique movement) correction by the registration roller pair 13 based on the detection result of the registration sensor 21.

[0029] The first paper sensor 22 detects the widthwise position of the paper P sent from the registration roller pair 13 to the first conveyor belt 8. Based on the detection result of the first paper sensor 22, the control device 110 (e.g., the main control unit 110a) can record an image on the paper P by ejecting ink from the ink ejection openings 18 corresponding to the width of the paper P, among the ink ejection openings 18 of the recording heads 17a to 17c of the line heads 11Y to 11K.

[0030] 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. In other words, the second paper sensor 23 detects the position in the conveying direction of the paper P conveyed by the first conveyor belt 8. The second paper sensor 23 is located upstream of the recording unit 9 and downstream of the first paper sensor 22 in the paper conveying direction. Based on the detection result by the second paper sensor 23, the control device 110 (for example, the main control unit 110a) can control the timing of ink ejection onto the paper P that reaches a position opposing the line heads 11Y to 11K (recording heads 17a to 17c) by the first conveyor belt 8.

[0031] The belt sensors 24 and 25 are reference detection sensors that detect a reference identification portion (not shown) provided on the first conveyor belt 8. The reference identification portion is a portion that indicates the reference for one revolution of the first conveyor belt 8. Since the positional relationship between the reference identification portion and the opening 80 (see FIG. 8) is known in advance, the belt sensors 24 and 25 detect the reference identification portion of the first conveyor belt 8, and based on the position of the detected reference identification portion, the belt sensors 24 and 25 can detect the position of each opening 80 (opening group 82) provided in the first conveyor belt 8 in the conveying direction. Therefore, the belt sensors 24 and 25 function as opening position detection portions that detect the positions of the openings 80 in the first conveyor belt 8.

[0032] In addition, marks may be formed at positions corresponding to each opening group 82 on the end 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.

[0033] The belt sensor 24 is located downstream of the recording unit 9 in the paper conveying direction (the running direction of the first conveyor belt 8). The belt sensor 25 is located upstream of the driven roller 6b that stretches the first conveyor belt 8 in the paper conveying direction. In this embodiment, the belt sensor 25 is located between the driven roller 6b and the tension roller 7b, but it may be located between the tension roller 7a and the roller 7b. The driven roller 6b is located upstream of the recording unit 9 in the running direction of the first conveyor belt 8. The belt sensor 24 also 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 timing based on the detection result of the belt sensor 24 or 25.

[0034] In addition, by detecting the position of the paper P with multiple sensors (first paper sensor 22, second paper sensor 23) and detecting the reference specific portion of the first conveyor belt 8 with multiple sensors (belt sensors 24 and 25), it is possible to correct errors in the detected position and detect abnormalities.

[0035] The above-mentioned first paper sensor 22, second paper sensor 23, and belt sensors 24 and 25 may be configured with a transmissive or reflective optical sensor, a CIS sensor (Contact Image Sensor), or the like.

[0036] Alternatively, the printer 100 may be configured to include a meandering detection sensor that detects meandering of the first transport belt 8, and to correct the meandering of the first transport belt 8 based on the detection result.

[0037] The printer 100 further includes an operation panel 27 , a storage unit 28 , a communication unit 29 , and a shutter driver 71 .

[0038] 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 information on the size of the paper P to be set in the paper feed cassette 2, that is, the size of the paper P to be transported by the first transport belt 8. The user can also operate the operation panel 27 to input the number of sheets of paper P to be printed and to instruct the start of a print job. The operation panel 27 also functions as a notification device that notifies users about the operating status of the printer 100 (image recording and flushing, which will be described later).

[0039] The storage unit 28 is a memory that stores the operation program of the control device 110 as well as various types of information, and is configured to include a ROM (Read Only Memory), a RAM (Random Access Memory), a non-volatile memory, etc. Information set by the operation panel 27 (e.g., information on the size and number of sheets of paper P) is stored in the storage unit 28.

[0040] The communication unit 29 is a communication interface for transmitting and receiving information to and from an external device (e.g., a personal computer (PC)). For example, when a user operates a PC and sends a print command together with image data to the printer 100, the image data and print command are input to the printer 100 via the communication unit 29. In the printer 100, the main control unit 110a controls the recording heads 17a to 17c based on the image data to eject ink, thereby recording an image on the paper P.

[0041] The shutter driving section 71 reciprocates a shutter 70 (see FIG. 9) provided in the ink passage 60a formed between the recording heads 17a to 17c and the ink receiving sections 32a to 32c (see FIG. 5). The configuration of the shutter driving section 71 will be described later.

[0042] The printer 100 of this embodiment also includes a control device 110. The control device 110 includes, 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 that constitutes the control device 110 is configured with one CPU, but may of course be configured with separate CPUs.

[0043] The main control unit 110a controls the operation of each unit of the printer 100. For example, the driving of each roller inside the printer 100, the ejection of ink from the recording heads 17a to 17c during image formation (other than during flushing), and the like are controlled by the main control unit 110a.

[0044] The flushing control unit 110b causes the recording heads 17a to 17c to perform flushing based on the position of the opening 80 detected by the belt sensor 24 or 25.

[0045] The paper supply control unit 110c is a recording medium supply control unit that controls the pair of registration rollers 13 as a recording medium supply unit. For example, the paper supply control unit 110c controls the pair of registration rollers 13 based on the position detection of the opening 80 by the belt sensor 24 or 25. Note that the paper supply control unit 110c can also control the pair of registration rollers 13 independently of the position detection of the opening 80 by the belt sensor 24 or 25 (regardless of the position detection).

[0046] The maintenance control unit 110d controls the recording heads 17a to 17c to execute the above-mentioned purging, which forcibly pushes out ink from each ink ejection port 18. When the maintenance control unit 110d causes the recording heads 17a to 17c to execute the purging, it also controls the driving of the above-mentioned maintenance unit 19 (for example, the movement of the recording unit 9 downward and the retraction).

[0047] 3, the printer 100 has ink recovery units 31Y, 31M, 31C, and 31K on the inner circumferential surface side of the first transport belt 8. The ink recovery units 31Y to 31K receive and recover ink that is ejected from the recording heads 17a to 17c and passes through the openings 80 of the first transport belt 8 when the recording heads 17a to 17c are caused to perform flushing. Therefore, the ink recovery units 31Y to 31K are provided at positions facing the recording heads 17a to 17c of the line heads 11Y to 11K across the first transport belt 8.

[0048] The second transport unit 12 has a second transport belt 12a and a dryer 12b. The second transport belt 12a is stretched around two drive rollers 12c and a driven roller 12d. The paper P transported by the first transport unit 5 and having an image recorded thereon by ink ejection by the recording unit 9 is transported by the second transport belt 12a, dried by the dryer 12b during transport, and transported to the decurler unit 14 described above.

[0049] [2. Details of the ink recovery section] Next, the configuration of the ink recovery units 31Y to 31K will be described in detail. Fig. 5 is a schematic diagram showing the ink recovery unit 31Y and a paper transport area adjacent to the ink recovery unit 31Y. For ease of explanation, the first transport belt 8 is omitted from Fig. 5. Below, the configuration around the ink recovery unit 31Y will be described, but since the ink recovery units 31M to 31K have the same configuration, their explanations will be omitted.

[0050] The ink recovery section 31Y is disposed between the pair of side frames 100a so as to face the recording heads 17a to 17c (see FIG. 2) constituting the line head 11Y. On the upper surface of the ink recovery section 31Y, ink receiving sections 32a to 32c for receiving ink droplets ejected from the recording heads 17a to 17c are provided.

[0051] The suction fan 40, which is a suction unit, is attached to two places on the side frame 100a, and one end of the suction duct 37 is connected to the suction fan 40. The other end of the suction duct 37 is provided with a plurality of suction ports 41. The suction ports 41 are arranged facing the inner peripheral surface of the first conveyor belt 8 (see FIG. 3). The first conveyor belt 8 is provided with a number of suction holes 8a (see FIG. 8) for suctioning air. By operating the suction fan 40, air on the outer peripheral surface side of the first conveyor belt 8 is sucked through the suction holes 8a. More specifically, air in the paper suction region R (hatched region in FIG. 5) excluding the ink receiving portions 32a to 32c is sucked. With this configuration, the paper P is sucked onto the conveying surface of the first conveyor belt 8 by the suction wind generated in the paper suction region R and conveyed.

[0052] Fig. 6 is a side cross-sectional view of the ink recovery unit 31Y taken in a direction perpendicular to the transport direction (cross-sectional view taken along the CC' arrow in Fig. 5). Fig. 7 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.

[0053] The suction path 35 is formed of, for example, a resin material, and has a first flow path 35a, a junction chamber 35b, and a second flow path 35c. The first flow path 35a communicates with the ink receiving portions 32a to 32c. The junction chamber 35b is where the three first flow paths 35a, which communicate with the ink receiving portions 32a to 32c, merge into one. The second flow path 35c has an upper end that communicates with the junction chamber 35b and a lower end that opens into the duct 37. With the above configuration, the ink receiving portions 32a to 32c are connected to the suction fan 40 via the suction path 35 and the duct 37.

[0054] Ink droplets contained in the air flow passing through the suction path 35 collide with the inner wall surfaces of the first flow path 35a and the merging chamber 35b and accumulate below. The ink accumulated below the waste ink tank 33 is discharged to the outside through the ink recovery path 36.

[0055] The ink recovery path 36 has an inclined portion 36a and an ink discharge tube 36b. The inclined portion 36 is formed adjacent to and below the first flow path 35a and the merging chamber 35b, and the ink discharge tube 36b is connected to the lowermost portion (bottom) of the inclined portion 36a. Ink droplets adhering to the inner wall surfaces of the first flow path 35a and the merging chamber 35b flow downward along the inner wall surfaces and then flow along the inclined portion 36a to be collected at one location (the lowermost portion). The ink then passes through the ink discharge tube 36b and is collected in a waste ink recovery bottle (not shown).

[0056] Although an ink recovery path 36 is provided here to recover ink accumulated inside the waste ink tank 33, an ink absorbent such as a melamine sponge may be placed inside the waste ink tank 33 instead of the ink recovery path 36. In that case, the ink absorbed by the ink absorbent is stored inside the waste ink tank 33 as it is, and is discarded or recovered when the waste ink tank 33 is replaced.

[0057] [3. Details of the first conveyor belt and belt support plate] Next, a detailed description will be given of the first transport belt 8 and the belt support plate 60 of the first transport unit 5. Fig. 8 is a partially enlarged view of the periphery of the opening group 82 of the first transport belt 8 used in the printer 100.

[0058] In this embodiment, a negative pressure suction method is adopted in which the paper P is adsorbed to the first transport belt 8 and transported by negative pressure suction by the suction fan 40. Therefore, a large number of suction holes 8a are formed over the entire area of ​​the first transport belt 8 to allow passage of an air flow (suction wind) for adsorbing the paper P to the first transport belt 8 by negative pressure suction.

[0059] The first conveyor belt 8 has a plurality of openings 80 that pass ink ejected from the nozzles (ink ejection ports 18) of the recording heads 17a to 17c during flushing. In this embodiment, an opening group 82 made up of the plurality of openings 80 is formed linearly across the entire width of the first conveyor belt 8.

[0060] 8, the shape of each opening 80 in plan view may be a circle, or may be a hole elongated in the belt width direction (arrow BB' direction) (e.g., an ellipse). The number of openings 80 in one row may be the same as the number of openings 80 (upstream-most openings 81) in the other row.

[0061] With the opening group 82 shown in FIG. 8 taken as one set, a plurality of sets of opening groups 82 are formed in one cycle of the first transport belt 8. The intervals in the transport direction between the sets of opening groups 82 are not the same, and the opening groups 82 are formed irregularly at positions according to the size of the paper P being transported. That is, the intervals between two sets of opening groups 82 adjacent to each other in the paper transport direction are not constant but different. In this case, the maximum interval between two sets of opening groups 82 adjacent to each other in the paper transport direction is longer than the length in the paper transport direction of the paper P of the smallest printable size (e.g., A4 size landscape) when the paper P is placed on the first transport belt 8.

[0062] 9 is a partial enlarged view of the periphery of the ink passage 60a of the belt support plate 60 used in the printer 100. The belt support plate 60 is disposed between the first transport belt 8 and the ink receivers 32a to 32c. The belt support plate 60 is disposed opposite the inner circumferential surface of the first transport belt 8, and supports the first transport belt 8 from the inside. The belt support plate 60 is formed with the ink passage 60a and ventilation holes 60b.

[0063] The ink passages 60a are formed at three locations facing the recording heads 17a to 17c, and are rectangular openings in a plan view extending from the lower surface of the first conveyor belt 8 to the ink receiving sections 32a to 32c. When flushing is performed, ink droplets that have passed through the openings 80 of the first conveyor belt 8 pass through the ink passages 60a and are collected in the ink receiving sections 32a to 32d. The ink passages 60a also function as a duct through which suction air generated by the suction fan 40 (see FIG. 5) passes to suck in ink droplets ejected from the recording heads 17a to 17c.

[0064] A shutter 70 is provided in each ink passage 60a. The shutter 70 is supported at both ends of the ink passage 60a in the width direction (arrow BB' direction) so as to be slidable in the transport direction (arrow A direction). The dimension of the shutter 70 in the transport direction is smaller than that of the ink passage 60a, and the shutter 70 overlaps with a part of the ink passage 60a in the transport direction. The shutter 70 can be moved back and forth in the transport direction by a shutter drive unit 71 consisting of a rack and pinion mechanism having a rack 71a to which the shutter 70 is fixed and a pinion gear 71b that meshes with a rack gear formed on the rack 71a.

[0065] 9 only illustrates the shutter drive unit 71 of the shutter 70 provided in the ink passage 60a (right side of FIG. 9) facing the ink receiving portion 32c, but the shutter drive unit 71 of a similar configuration is also connected to the shutters 70 provided in the ink passage 60a (left side and center of FIG. 9) facing the ink receiving portions 32a, 32b. Also, the shutter 70 provided in the ink passage 60a (center of FIG. 9) facing the ink receiving portion 32b is located at a different position in the transport direction, and therefore reciprocates at a different timing than the other shutters 70, as described below.

[0066] The ventilation holes 60b are formed around the ink passage 60a in an area where the ink passage 60a is formed in the transport direction of the first transport belt 8. The suction fan 40 (see FIG. 5) sucks air through the ventilation holes 60b and suction holes 8a (see FIG. 8) formed in the first transport belt 8, so that the paper P is adsorbed onto the first transport belt 8 by negative pressure.

[0067] [4. Adjusting the negative pressure in the ink passage] Next, a procedure for adjusting the negative pressure of the ink passage 60a by the shutter 70, which is a characteristic feature of the printer 100 of this embodiment, will be described. Fig. 10 is a plan view showing the arrangement of the shutter 70 of the ink passage 60a when flushing is performed. Fig. 11 is a side cross-sectional view (cross-sectional view taken along the arrow XX in Fig. 10) showing the arrangement of the shutter 70 of the ink passage 60a when flushing is performed. Note that Figs. 10, 11 and the following Figs. 13 to 20 show the arrangement of the shutter 70 of the ink passage 60a in the ink receiving section 32a, but the arrangement of the shutter 70 of the ink passage 60a in the ink receiving sections 32b and 32c is similar.

[0068] When flushing is performed before printing on the paper P (or between sheets of paper), the shutter 70 is positioned at the center of the ink passage 60a in the transport direction (direction of arrow A) as shown in Figures 10 and 11. This weakens the suction force of the suction wind passing downward through the ink passage 60a, making it possible to suppress the flying up of ink droplets that have been ejected from the recording head 17a and turned into a mist.

[0069] In addition, if the upper surface of the shutter 70 is flat, when ink droplets ejected by flushing land on the shutter 70, they may accumulate on the upper surface of the shutter 70 and not be collected in the ink receiving portions 32a to 32c. Therefore, as shown in Fig. 12, it is preferable to form a pair of inclined surfaces 70b that incline downward toward the upstream side and the downstream side in the transport direction from a ridge line 70a extending along the width direction of the shutter 70 (the direction of the arrow BB' in Fig. 10).

[0070] As a result, ink droplets that land on the upper surface of the shutter 70 flow down along the inclined surface 70b due to gravity and the downward suction wind passing through the ink passage 60a, and are collected in the ink receiving portions 32a to 32c.

[0071] Fig. 13 is a plan view showing the arrangement of the shutter 70 immediately before the leading edge of the paper P passes through the ink passage 60a during image recording. Fig. 14 is a side cross-sectional view (cross-sectional view taken along the arrow XX in Fig. 13) showing the arrangement of the shutter 70 immediately before the leading edge of the paper P passes through the ink passage 60a.

[0072] When recording an image on paper P, as shown in Figures 13 and 14, the shutter 70 is moved in advance from the center of the ink passage 60a in the transport direction to the upstream end (the bottom end in Figure 13, the right end in Figure 14).

[0073] Fig. 15 is a plan view showing the operation of the shutter 70 when the leading edge of the paper P is passing through the ink passage 60a. Fig. 16 is a side cross-sectional view (cross-sectional view taken along the arrow XX in Fig. 15) showing the operation of the shutter 70 when the leading edge of the paper P is passing through the ink passage 60a during image recording.

[0074] When the leading edge of the paper P passes through the ink passage 60a, the shutter 70 is moved from the upstream end to the downstream end of the ink passage 60a in accordance with the transport of the paper P so that the shutter 70 is positioned slightly downstream in the transport direction of the leading edge of the paper P (upper side in FIG. 15, left side in FIG. 16). This strengthens the suction force of the leading edge of the paper P when the paper P enters below the recording head 17a, suppresses the paper P from jumping up (curling), and prevents the leading edge of the paper P from colliding with the recording head 17a.

[0075] In addition, in Figure 15, the shutter 70 corresponding to the ink receiving portion 32b is positioned at the upstream end in the transport direction, but when the paper P is transported further downstream (upward in Figure 15), the shutter 70 corresponding to the ink receiving portion 32b also moves downstream in line with the transport of the paper P.

[0076] Fig. 17 is a plan view showing the arrangement of the shutter 70 after the leading edge of the paper P has passed through the ink passage 60a. Fig. 18 is a side cross-sectional view (cross-sectional view taken along the arrow XX in Fig. 17) showing the arrangement of the shutter 70 after the leading edge of the paper P has passed through the ink passage 60a.

[0077] After the leading edge of the paper P has passed through the ink passage 60a, the shutter 70 is returned to the upstream end of the ink passage 60a (the bottom end in Figure 17, the right end in Figure 18) in preparation for the passage of the trailing edge of the paper P described below.

[0078] Fig. 19 is a plan view showing the operation of the shutter 70 when the rear end of the paper P is passing through the ink passage 60a. Fig. 20 is a side cross-sectional view (cross-sectional view taken along the arrow XX in Fig. 19) showing the operation of the shutter 70 when the rear end of the paper P is passing through the ink passage 60a.

[0079] When the rear end of the paper P passes through the ink passage 60a, the shutter 70 is moved from the upstream end to the downstream end of the ink passage 60a in accordance with the transport of the paper P so that the shutter 70 is positioned slightly downstream in the transport direction of the rear end of the paper P (upper side in FIG. 19, left side in FIG. 20). This strengthens the suction force at the rear end of the paper P to suppress bouncing (curling) and prevent the rear end of the paper P from colliding with the recording head 17a.

[0080] When flushing is performed in the interval (between sheets) between when the trailing edge of the paper P passes through the ink passage 60a and when the next paper P arrives, or when flushing is performed after image recording is completed, the shutter 70 is moved again to the center of the ink passage 60a in the transport direction (see Figs. 10 and 11). When image recording is performed continuously without flushing, the shutter 70 is moved to the upstream side of the ink passage 60a in the transport direction until the leading edge of the next paper P passes through (see Figs. 13 and 14). The above operations are repeated every time flushing and image recording are performed.

[0081] As described above, ink droplets can be collected more efficiently during flushing than in the past by controlling the negative pressure adjustment using the shutter 70 that is driven separately from the transport of the paper P. Furthermore, by increasing the suction negative pressure at the leading and trailing ends of the paper P during image recording, it is possible to prevent the paper P from coming into contact with the nozzle faces of the recording heads 17a to 17c.

[0082] [5. Other] The present invention is not limited to the above embodiment, and various modifications are possible within the scope of the present invention. For example, in the above embodiment, the configuration in which three recording heads 17a to 17c are arranged in a staggered manner for each color of the line heads 11Y to 11K has been described, but the present invention is not limited to this configuration. For example, the present invention can also be applied to a configuration in which the recording heads 17a to 17c are arranged in a straight line.

[0083] In the above embodiment, a rack and pinion mechanism consisting of the rack 71a and the pinion gear 71b is used as the shutter driving unit 71, but a driving mechanism other than the rack and pinion mechanism can also be used.

[0084] In addition, in the above embodiment, a configuration was described in which a first conveyor belt 8 is used in which opening groups 82 consisting of a plurality of openings 80 are irregularly arranged at positions according to the paper size in the conveying direction, but it is also possible to use a first conveyor belt 8 in which opening groups 82 are arranged in a row at regular intervals in the paper conveying direction.

[0085] In addition, in the above embodiment, a color printer that records color images using four colors of ink has been described as an inkjet recording device, but the present invention can also be applied to a monochrome printer that records monochrome images using black ink. [Industrial Applicability]

[0086] The present invention can be used in inkjet recording devices such as inkjet printers. [Explanation of symbols]

[0087] 8 First conveyor belt (conveyor member) 17a~17c Recording head 18 Ink outlet (nozzle) 31Y~31K Ink recovery section 32a~32c Ink receiving section 33 Waste ink tank 35 Suction Path 36 Ink collection route 37 Duct 40 Suction fan (suction section) 60 Belt support plate (support plate) 60a Ink passage 70 Shutter 70b Slope 71 Shutter drive unit 80 Opening 82 Openings 100 Printers (inkjet recording devices) 110 Control device (control unit) P Paper (recording medium)

Claims

1. a recording head having a plurality of nozzles for ejecting ink; a conveying member having a plurality of openings through which the ink ejected from the recording head passes, the conveying member conveying a recording medium; a control unit that controls driving of the recording head and the transport member to perform flushing by ejecting the ink from the nozzles of the recording head and causing the ink to pass through any one of the plurality of openings at a timing different from a timing contributing to image recording; an ink recovery unit disposed opposite the recording head with the transport member interposed therebetween, the ink recovery unit having an ink receiving unit that receives the ink that has passed through the opening during the flushing process; an ink passage formed between the transport member and the ink receiving portion, through which the ink passes after passing through the opening; a suction section connected to the ink receiving section and configured to suck the ink that has passed through the opening together with air within the ink passage; In an inkjet recording apparatus comprising: a shutter that overlaps a portion of the ink passage in a transport direction of the recording medium and is reciprocally movable between an upstream side and a downstream side of the ink passage along the transport direction; A shutter driving unit that drives the shutter; Equipped with The control unit controls the shutter driving unit, When the flushing is performed, the shutter is disposed at a center portion of the ink passage in the transport direction, an ink jet recording device characterized in that, while the leading and trailing ends of the recording medium are passing through the ink passage during image recording, the shutter is moved from the upstream side to the downstream side of the ink passage in accordance with the transport of the recording medium so that the shutter is positioned immediately downstream of the leading and trailing ends of the recording medium in the transport direction.

2. 2. The inkjet recording device according to claim 1, wherein the control unit moves the shutter to the upstream side of the ink passage after the leading end of the recording medium has passed through the ink passage and before the trailing end of the recording medium has passed through the ink passage.

3. The inkjet recording device according to claim 1, characterized in that, when the control unit performs the flushing at an interval of the recording medium when the image recording is performed continuously or after the image recording is completed, the control unit moves the shutter to a center portion of the ink passage in the transport direction after the rear end of the recording medium has passed through the ink passage.

4. 2. The inkjet recording apparatus according to claim 1, wherein the upper surface of the shutter is formed with a pair of inclined surfaces that are inclined downward toward the upstream side and downstream side in the transport direction.

5. a support plate for supporting the conveying member is disposed between the conveying belt and the ink receiving section, 5. The ink jet recording apparatus according to claim 1, wherein the ink passage is formed in the support plate.

Images