Printing apparatus and ink mist collection method

Abstract

To suppress the occurrence of a failure in an air flow generation mechanism for collecting ink mist.SOLUTION: The recovery air flow Fc for sucking the ink mist from the recovery nozzle 4 to recover the ink mist is generated by the vacuum flow 62. The vacuum flow 62 has a slit 627 that opens to the vacuum flow path 623 between the intake port 624 and the exhaust port 625. The slit 627 generates a negative pressure on the intake port 624 side of the slit 627 in the vacuum flow path 623 by injecting the pressurized gas Gp into the vacuum flow path 623 toward the exhaust port 625, and generates the recovery air flow Fc by the negative pressure.SELECTED DRAWING: Figure 8A

Description

[Technical Field]

[0001] The present invention relates to a technique for collecting ink mist that is generated when ink is ejected onto a printing medium to print an image. [Background technology]

[0002] Patent Document 1 discloses a technique for collecting ink mist generated when a print head ejects ink droplets onto a print medium. In this technique, a suction fan is used to suck ink from a suction port facing the print medium, thereby collecting the ink mist from the suction port. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6008929 Summary of the Invention [Problem to be solved by the invention]

[0004] In this way, in the above technology, the airflow for collecting the ink mist is generated by the suction fan. However, the suction fan is a device that rotates by receiving a supply of power and has electrical components such as circuits and wiring. Therefore, if ink mist adheres to the suction fan, there is a risk that the electrical components of the suction fan will malfunction.

[0005] The above-mentioned problem can also occur when a vacuum pump is used to generate the airflow for collecting the ink mist. Like a suction fan, a vacuum pump is a device that rotates by receiving power and includes electrical components such as circuits and wiring. Therefore, if ink mist adheres to the vacuum pump, there is a risk that the electrical components of the vacuum pump will malfunction.

[0006] The present invention has been made in consideration of the above-mentioned problems, and has an object to make it possible to prevent failures in an airflow generating mechanism for recovering ink mist. [Means for solving the problem]

[0007] The printing device according to the present invention comprises a print medium transport unit that transports the print medium in a transport direction, an ejection head that faces the print medium and ejects ink onto the print medium, a recovery nozzle arranged near the ejection head, an airflow generating pipe that sucks ink mist generated by the ejection head ejecting ink through the recovery nozzle and generates a recovery airflow for recovering the ink mist, and a gas supply unit that supplies pressurized gas to the airflow generating pipe, the airflow generating pipe having an intake port, an exhaust port, a pipe flow path extending from the intake port to the exhaust port, and a supply port that opens into the pipe flow path between the intake port and the exhaust port, the gas supply unit supplies pressurized gas to the supply port, and the supply port injects the pressurized gas supplied from the gas supply unit into the pipe flow path toward the exhaust port, thereby generating a negative pressure on the intake port side of the supply port of the pipe flow path, and the negative pressure generates a recovery airflow, the recovery airflow is generated along a recovery path that flows from the recovery nozzle through the intake port into the pipe flow path and then flows out of the exhaust port.

[0008] The ink mist recovery method according to the present invention is an ink mist recovery method in which ink mist generated by an ejection head ejecting ink onto a printing medium transported in a transport direction is recovered by a recovery nozzle located near the ejection head, and includes a step of supplying pressurized gas to the airflow generating piping to generate a recovery airflow by the airflow generating piping for sucking the ink mist generated by the ejection head ejecting ink through the recovery nozzle and recovering the ink mist, the airflow generating piping having an intake port, an exhaust port, a piping flow path extending from the intake port to the exhaust port, and a supply port opening into the piping flow path between the intake port and the exhaust port, the supply port injecting pressurized gas into the piping flow path toward the exhaust port side to generate a negative pressure on the intake port side of the supply port of the piping flow path, and the recovery airflow is generated by this negative pressure, and the recovery airflow is generated along a recovery path that flows from the recovery nozzle through the intake port into the piping flow path and then flows out of the exhaust port.

[0009] According to the present invention (printing device and ink mist recovery method) configured as described above, a recovery airflow for sucking ink mist from the recovery nozzle and recovering the ink mist is generated by the airflow generating pipe. This airflow generating pipe has a supply port that opens to the pipe flow path between the intake port and the exhaust port. The supply port injects pressurized gas into the pipe flow path toward the exhaust port, generating negative pressure in the pipe flow path, and this negative pressure generates a recovery airflow. This recovery airflow is generated along a recovery path that flows from the recovery nozzle through the intake port into the pipe flow path and then out the exhaust port. In other words, the recovery airflow can be generated simply by supplying pressurized gas prepared by equipment (e.g., utility) separate from the printing device to the supply port of the airflow generating pipe. This airflow generating pipe does not include electronic components. This makes it possible to prevent malfunctions in the airflow generating mechanism (airflow generating pipe) for recovering ink mist.

[0010] Furthermore, the present invention can achieve the following effects. Specifically, the air flow generating pipe has a simple configuration that does not include any electronic components. Therefore, the air flow generating pipe to which ink mist has adhered can be easily cleaned. Furthermore, while suction fans and vacuum pumps generate vibrations as they rotate, the air flow generating pipe does not generate vibrations. Therefore, ink ejection from the ejection head can be stabilized without causing vibrations to the ejection head.

[0011] The present invention can also be suitably applied to printing devices that further include a filter disposed in the recovery path to capture ink mist contained in the recovery airflow traveling along the recovery path. In other words, when a suction fan or vacuum pump is used to generate the recovery airflow, it was necessary to place the filter upstream of the suction fan or vacuum pump to prevent ink mist from adhering to the suction fan or vacuum pump. In contrast, the present invention prevents problems such as malfunctions and cleaning associated with ink mist adhering to the airflow generation pipe. Therefore, the filter can be positioned either downstream or upstream of the airflow generation pipe. This increases the flexibility in filter placement.

[0012] The printing device may also be configured so that the filter is located downstream of the exhaust port in the recovery path, and the recovered airflow passes through the filter after flowing out of the exhaust port. In this configuration, the filter is located relatively far from the print medium. This prevents the print medium from being contaminated by ink splashed from the filter during maintenance work such as cleaning or replacing the filter. Furthermore, since there is relatively more space downstream of the exhaust port, a large filter can be easily placed.

[0013] The printing device may also be configured to further include a mist exhaust duct connected to the exhaust port from the downstream side of the recovery path and communicating with the exhaust port, the mist exhaust duct having a filter arrangement section in which a filter is arranged, and the filter arranged in the filter arrangement section captures ink mist contained in the recovered airflow that flows out from the exhaust port and proceeds through the mist exhaust duct.

[0014] In this case, the printing device may be configured so that the cross-sectional area of ​​the filter is larger than the cross-sectional area of ​​the piping flow path of the airflow generating piping. This reduces the frequency of maintenance work such as cleaning and replacing the filter. In addition, the average flow velocity of the gas passing through the filter can be kept slow, making it possible to use a variety of filters.

[0015] The printing device may also be configured so that the filter placement section is provided at the downstream end of the mist exhaust duct in the recovery path and opens toward the downstream side of the recovery path. By locating the filter in this manner, it is possible to reduce the loss of negative pressure generated by the airflow generating pipe to generate a recovery airflow. As a result, a recovery airflow can be reliably generated and ink mist can be efficiently recovered.

[0016] The printing device may also be configured to further include a pressure detection unit that detects the pressure at a position in the recovery path between the recovery nozzle and the airflow generating pipe, making it possible to check for any abnormalities in the pressure.

[0017] The printing device may also be configured to further include a notification unit that issues a warning when the pressure detected by the pressure detection unit is outside a predetermined range. In this configuration, if an abnormality occurs in the pressure, the operator can take appropriate action. [Effects of the Invention]

[0018] As described above, according to the present invention, it is possible to prevent failure of the airflow generating mechanism for recovering ink mist. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a front view schematically showing a printing apparatus according to the present invention. [Figure 2A] FIG. 2 is a diagram schematically illustrating an example of a mist collection unit included in the printing apparatus of FIG. 1. [Figure 2B]FIG. 2 is a diagram schematically illustrating an example of a mist collection unit included in the printing apparatus of FIG. 1. [Figure 3A] FIG. 2 is a perspective view schematically showing the external configuration of a recovery nozzle. [Figure 3B] FIG. 2 is a front view schematically showing the external configuration of the recovery nozzle. [Figure 4] FIG. 3 is a perspective view schematically showing the internal configuration of the recovery nozzle. [Figure 5A] FIG. 3 is a cross-sectional view schematically showing the internal configuration of the recovery nozzle. [Figure 5B] FIG. 3 is a cross-sectional view schematically showing the internal configuration of the recovery nozzle. [Figure 6] FIG. 4 is a diagram illustrating the operation of the recovery nozzle. [Figure 7] FIG. 4 is a perspective view schematically showing an exhaust connector of the exhaust duct. [Figure 8A] FIG. 2 is a cross-sectional view schematically showing the configuration of a vacuum flow. [Figure 8B] FIG. 3 is a cross-sectional view schematically showing the configuration of the mist capturing section. [Figure 8C] FIG. 2 is a block diagram showing the configuration of the mist collection unit. [Figure 9] FIG. 4 is a partial cross-sectional view that schematically illustrates, with emphasis, the operation performed by raising and lowering the ejection head and the recovery nozzle. [Figure 10] FIG. 2 is a perspective view schematically illustrating the external configuration of the cushioning material. [Figure 11] FIG. 10 is a partial cross-sectional view that schematically illustrates, with emphasis, the operation performed by raising and lowering the ejection head and the recovery nozzle in a configuration that includes a buffer material. [Figure 12A] FIG. 10 is a diagram schematically illustrating the loss of negative pressure caused by vacuum flow. [Figure 12B] FIG. 10 is a diagram schematically illustrating the loss of negative pressure caused by vacuum flow. DETAILED DESCRIPTION OF THE INVENTION

[0020] FIG. 1 is a front view showing a schematic diagram of a printing device according to the present invention. In FIG. 1 and the following figures, the horizontal X direction, the horizontal Y direction perpendicular to the X direction, and the vertical Z direction are indicated as appropriate. Furthermore, one side X1 and the other side X2 of the X direction are indicated as appropriate. Here, the one side X1 and the other side X2 face in opposite directions.

[0021] The printing device 1 includes a housing 11, a color printing unit 12 arranged within the housing 11, a white printing unit 13 arranged above the color printing unit 12 within the housing 11, and a transport unit 2 that transports the printing medium M using a plurality of rollers arranged within the housing 11. In other words, the housing 11 accommodates the color printing unit 12, the white printing unit 13, and the transport unit 2.

[0022] The color printing unit 12 has a plurality of (four) ejection heads 121 arranged above the printing medium M transported by the transport unit 2 in the direction of travel of the printing medium M (the direction from the other side X2 to the one side X1). Each of the ejection heads 121 has a nozzle facing from above toward the surface M1 of the printing medium M passing below it, and ejects different color inks from the nozzles using an inkjet method. Here, color ink refers to ink other than white, and includes inks such as cyan, magenta, yellow, and black. In this way, each of the ejection heads 121 of the color printing unit 12 prints a color image on the surface M1 of the printing medium M by ejecting color inks from above onto the surface M1 of the printing medium M passing below it.

[0023] The white printing unit 13 also has a single ejection head 131 arranged above the printing medium M transported by the transport unit 2. The ejection head 131 has nozzles facing from above toward the surface M1 of the printing medium M passing below it, and ejects white ink from the nozzles using an inkjet method. In this way, the ejection head 131 of the white printing unit 13 prints a white image on the surface M1 of the printing medium M by ejecting white ink from above onto the surface M1 of the printing medium M passing below it.

[0024] An inlet 111 opens in the side wall of the housing 11 on the other side X2, and the printing medium M is carried into the housing 11 through the inlet 111. In contrast, the transport unit 2 has an inlet section 21. The inlet section 21 has a plurality of rollers 211 arranged in the X direction below the color printing unit 12, and transports the printing medium M carried in through the inlet 111 from the other side X2 to the one side X1 while supporting the printing medium M with the plurality of rollers 211.

[0025] The transport unit 2 also has an upward transport unit 22 provided on one side X1 of the carry-in unit 21. The upward transport unit 22 has a plurality of rollers 221 arranged in the Z direction on one side X1 of the color printing unit 12. The upward transport unit 22 changes the traveling direction of the printing medium M from one side X1 to the upward side by bending the printing medium M transported by the carry-in unit 21 upward using the roller 221 located at the bottom of the plurality of rollers 221, and then transports the printing medium M upward while being supported by the plurality of rollers 221. In this way, the printing medium M is transported from the lower side of the color printing unit 12 to the upper side by the upward transport unit 22.

[0026] Furthermore, the conveying unit 2 has an upper conveying unit 23 provided above the color printing unit 12. The upper conveying unit 23 has a plurality of rollers 231 arranged in the X direction above the color printing unit 12. The upper conveying unit 23 changes the traveling direction of the printing medium M from the upper side to the other side X2 by using a roller 231 located at the end of one side X1 of the plurality of rollers 231 to bend the printing medium M conveyed from the upward conveying unit 22 to the other side X2, and then conveys the printing medium M to the other side X2 while being supported by the plurality of rollers 231.

[0027] The conveying unit 2 also has a downward conveying unit 24 provided on the other side X2 of the upper conveying unit 23. The downward conveying unit 24 has a plurality of rollers 241 arranged in the Z direction on the other side X2 of the color printing unit 12. The downward conveying unit 24 changes the traveling direction of the print medium M from the other side X2 to the downward side by bending the print medium M conveyed from the upper conveying unit 23 downward using the roller 241 located at the upper end of the plurality of rollers 241, and then conveys the print medium M downward while being supported by the rollers 241. Of the plurality of rollers 241 included in the downward conveying unit 24, the uppermost roller 241 is located above the respective ejection heads 121 of the color printing unit 12, and the lowermost roller 241 is located below the respective ejection heads 121 of the color printing unit 12. In other words, the downward conveying unit 24 conveys the print medium M from the upper side to the lower side of the color printing unit 12.

[0028] The transport unit 2 further includes a color transport unit 25 located below the upper transport unit 23 and on one side X1 of the downward transport unit 24. The color transport unit 25 includes a plurality of rollers 251 arranged in the X direction and in contact with the back surface M2 of the printing medium M, and the printing medium M transported from the downward transport unit 24 is supported below the color printing unit 12 by the plurality of rollers 251. In this manner, the plurality of rollers 251 of the color transport unit 25 contact the back surface M2 of the printing medium M transported from the downward transport unit 24 from below, thereby supporting the printing medium M from below, and transporting the printing medium M from the other side X2 to the one side X1. Each ejection head 121 of the color printing unit 12 ejects color ink from above onto the front surface M1 of the printing medium M transported along the front surface M1 by the color transport unit 25.

[0029] At this time, the front surface M1 of the printing medium M transported by the color transport unit 25 faces upward, and the back surface M2 of the printing medium M faces downward. More specifically, the printing medium M is transported through the transport entrance 111 with its front surface M1 facing upward, and is transported by the transport unit 21 from the other side X2 to the one side X1. After passing through the transport unit 21, the printing medium M is turned upside down by the upward transport unit 22 and the upper transport unit 23, and then transported by the upper transport unit 23 from the one side X1 to the other side X2. Therefore, the front surface M1 of the printing medium M transported by the upper transport unit 23 faces downward. After passing through the upper transport unit 23, the printing medium M is turned upside down by the downward transport unit 24 and the color transport unit 25, and then transported by the color transport unit 25 from the other side X2 to the one side X1. Therefore, the front surface M1 of the printing medium M transported by the color transport unit 25 faces upward.

[0030] The transport unit 2 also has rollers 261 and 262 that come into contact with the printing medium M upstream of the color transport unit 25 in the traveling direction of the printing medium M. The roller 261 is a drive roller that drives the printing medium M.

[0031] Furthermore, the transport unit 2 has a reversing transport unit 27 that turns upside down twice the printing medium M transported from the color transport unit 25 to one side X1. This reversing transport unit 27 has multiple rollers 271, 272 that are arranged in the Z direction on one side X1 of the color transport unit 25 and come into contact with the back surface M2 of the printing medium M. Of the multiple rollers 271, 272, the uppermost roller 271 is a drive roller that drives the printing medium M. This roller 271 bends the printing medium M transported from the color transport unit 25 downward, thereby changing the traveling direction of the printing medium M from one side X1 to the bottom. In addition, the lowermost roller 272 bends the printing medium M transported from the roller 271 to the other side X2, thereby changing the traveling direction of the printing medium M from the bottom to the other side X2. In this way, the rollers 271, 272 contacting the back surface M2 of the printing medium M turn the printing medium M upside down, so that the back surface M2 of the printing medium M faces upward and the front surface M1 of the printing medium M faces downward.

[0032] The reverse conveying section 27 also has a plurality of rollers 273 that are arranged in the X direction below the color conveying section 25 and on the other side X2 of the rollers 272 and that come into contact with the back surface M2 of the printing medium M. These rollers 273 convey the printing medium M conveyed from the rollers 272 from one side X1 to the other side X2. In this way, the printing medium M with the back surface M2 facing upward is conveyed from one side X1 to the other side X2 by the plurality of rollers 273 that come into contact with the back surface M2 of the printing medium M.

[0033] Furthermore, the reverse conveying section 27 has a plurality of rollers 273 and a plurality of rollers 274, 276, and 277 that are arranged in the Z direction on the other side X2 of the downward conveying section 24 and that come into contact with the back surface M2 of the printing medium M. Of the plurality of rollers 274 to 277, the bottom roller 274 bends the printing medium M conveyed from the plurality of rollers 273 upward, thereby changing the traveling direction of the printing medium M from the other side X2 to the top, and the top roller 277 bends the printing medium M conveyed from roller 274 via roller 276 toward one side X1, thereby changing the traveling direction of the printing medium M from the top to one side X1. In this way, the rollers 274 to 277 that come into contact with the back surface M2 of the printing medium M turn the printing medium M upside down, so that the front surface M1 of the printing medium M faces upward and the back surface M2 of the printing medium M faces downward.

[0034] The reverse conveying section 27 also has a roller 278 that is disposed above the upper conveying section 23 and on one side X1 of the roller 277 and that comes into contact with the back surface M2 of the printing medium M. The roller 278 conveys the printing medium M conveyed from the roller 277 from the other side X2 toward the one side X1. In this way, the roller 278 that comes into contact with the back surface M2 of the printing medium M conveys the printing medium M with the front surface M1 facing upward from the other side X2 toward the one side X1.

[0035] In this way, the reverse conveying unit 27 conveys the printing medium M conveyed from the color conveying unit 25 downward by the rollers 271 and 272, and then changes the traveling direction of the printing medium M to the other side X2 by the roller 272 and conveys the printing medium M upside down, thereby inverting the front surface M1 and back surface M2 of the printing medium M. Next, the reverse conveying unit 27 conveys the printing medium M from the one side X1 to the other side X2 by the multiple rollers 273, and then conveys the printing medium M upward by the rollers 274 to 277. Furthermore, the reverse conveying unit 27 changes the traveling direction of the printing medium M to the one side X1 by the roller 277, thereby again inverting the front surface M1 and back surface M2 of the printing medium M upside down, and conveys the printing medium M from the other side X2 to the one side X1 by the roller 278.

[0036] In this way, the reverse conveying unit 27 turns the front surface M1 and back surface M2 of the printing medium M upside down twice using only the rollers 271-278, which come into contact with the back surface M2 of the printing medium M and rotate while wrapping the back surface M2 around it. In other words, the reverse conveying unit 27 can turn the front surface M1 and back surface M2 of the printing medium M upside down twice without providing any support members such as rollers or air turn bars on the front surface M1 side of the printing medium M.

[0037] The conveying unit 2 also has a white conveying unit 28 that is provided above the upper conveying unit 23 and on one side X1 of the rollers 278 of the reverse conveying unit 27. This white conveying unit 28 has rollers 281, and the printing medium M conveyed from the rollers 278 of the reverse conveying unit 27 is supported below the white printing unit 13 by the rollers 281. In this way, the rollers 281 of the white conveying unit 28 contact from below the back surface M2 of the printing medium M conveyed from the rollers 278 of the reverse conveying unit 27, thereby supporting the printing medium M from below and conveying the printing medium M from the other side X2 to the one side X1. The ejection head 131 of the white printing unit 13 then ejects white ink from above onto the front surface M1 of the printing medium M that is conveyed along the front surface M1 by the white conveying unit 28.

[0038] Furthermore, the transport unit 2 has an output unit 29 that is provided above the upper transport unit 23 and on one side X1 of the white transport unit 28. The output unit 29 has a plurality of rollers 291, 292, 293 that are arranged in the X direction and that come into contact with the back surface M2 of the printing medium M. The roller 291 is a drive roller that drives the printing medium M, and the rollers 292 and 293 rotate as the printing medium M is transported. Meanwhile, an output opening 112 opens in the side wall on the one side X1 of the housing 11, and the plurality of rollers 291 to 293 of the output unit 29 transport the printing medium M from the other side X2 toward the one side X1 while contacting the back surface M2 of the printing medium M from below, thereby transporting the printing medium M from the other side X2 toward the one side X1.

[0039] In the printing device 1 described above, the transport unit 2 transports the printing medium M along the path shown in FIG. 1 using multiple rollers. The color printing unit 12 ejects color inks onto the printing medium M transported by the transport unit 2 to print a color image (color image printing), and the white printing unit 13 ejects white ink onto the printing medium M to print a white image (white image printing). In this printing device 1, some of the color inks ejected from each ejection head 121 of the color printing unit 12 scatter as ink mist. Also, some of the white ink ejected from the ejection head 131 of the white printing unit 13 scatters as ink mist. Therefore, the printing device 1 is provided with a mist collection unit 3 ( FIG. 2A ) for collecting the ink mist. Note that the following description will focus on the mist collection unit 3 for the color printing unit 12, but a similar mist collection unit 3 can also be provided for the white printing unit 13.

[0040] 2A and 2B are diagrams schematically illustrating an example of a mist collection unit included in the printing apparatus of FIG. 1. In FIG. 2A, the rollers included in the transport unit 2 are collectively referred to as rollers 201. FIG. 2A also illustrates one of a pair of support plates 202 included in the transport unit 2. That is, the transport unit 2 has a pair of support plates 202 arranged at a distance in the Y direction. The roller 201 is arranged parallel to the Y direction between the pair of support plates 202 and is rotatably supported by the pair of support plates 202. The print medium M is transported in the transport direction Dm by the transport unit 2.

[0041] The mist collection unit 3 has a collection nozzle 4 that is arranged above the print medium M supported by the transport unit 2. In particular, the mist collection unit 3 is provided with a plurality of collection nozzles 4 corresponding to the plurality of ejection heads 121, respectively, and each of the plurality of collection nozzles 4 is arranged downstream in the transport direction Dm of the corresponding ejection head 121. A base frame 14 is arranged between the collection nozzle 4 and the ejection head 121 that corresponds to the collection nozzle 4, and the collection nozzle 4 is fixed to the corresponding ejection head 121 by the base frame 14.

[0042] FIG. 3A is a perspective view schematically illustrating the exterior configuration of the collection nozzle, and FIG. 3B is a front view schematically illustrating the exterior configuration of the collection nozzle. FIG. 3A illustrates one side Y1 and the other side Y2 in the Y direction, and the downstream side Dmd and the upstream side Dmu in the conveying direction Dm. Here, the one side Y1 and the other side Y2 face opposite each other, and the downstream side Dmd and the upstream side Dmu face opposite each other. As shown in FIGS. 2A and 2B, the mist collection unit 3 has multiple collection nozzles 4 with different inclinations, but these nozzles share a common configuration except for the inclinations. Therefore, FIGS. 3A and 3B illustrate a mist collection unit 3 arranged parallel to the Z direction.

[0043] The recovery nozzle 4 has a nozzle housing 41 that is long in the Y direction, and a flow path space S (FIGS. 5A and 5B) that serves as an air flow path is provided inside the nozzle housing 41. The nozzle housing 41 has side covers 411 and 412 that are spaced apart in the transfer direction Dm. The side cover 411 stands upright parallel to the Z direction on the upstream side Dmu of the side cover 412 (i.e., on the side of the corresponding ejection head 121). The side cover 412 stands upright parallel to the Z direction on the downstream side Dmd of the side cover 411 (i.e., on the opposite side of the corresponding ejection head 121).

[0044] The nozzle housing 41 also has side covers 413 and 414 spaced apart in the Y direction. The side cover 413 extends in the Z direction while inclining in the Z direction on one side Y1 of the side cover 414. The side cover 414 stands parallel to the Z direction on the other side Y2 of the side cover 413. The side covers 411, 412, 413, and 414 surround the flow path space S inside the nozzle housing 41 from the sides (horizontally). The side cover 411 also has a top cover 415 that is provided to connect the upper ends of the side covers 411, 412, 413, and 414. The top cover 415 covers the flow path space S surrounded by the side covers 411, 412, 413, and 414 from above.

[0045] A bottom cover 417 extending in the Y direction is provided on the bottom 416 of the nozzle housing 41. The bottom cover 417 is provided horizontally so as to connect the side covers 412, 414. In other words, the side cover 412 stands upward from the end of the bottom cover 417 on the downstream side Dmd, and the side cover 414 stands upward from the end of the bottom cover 417 on the other side Y2. The bottom cover 417 extends from the lower end of the side cover 412 to the upstream side Dmu, and faces the end of the upstream side Dmu of the flow path space S inside the nozzle housing 41 from below.

[0046] Furthermore, the nozzle housing 41 has a nozzle intake section 42 that protrudes downward from a bottom cover 417 at the bottom 416 of the nozzle housing 41. The nozzle intake section 42 extends in the Y direction so as to be adjacent to the bottom cover 417 from the upstream side Dmu. An intake opening Ani that extends in the Y direction opens downward at the bottom 421 (lower end) of the nozzle intake section 42. The intake opening Ani of the nozzle intake section 42 faces the flow path space S from below on the upstream side Dmu of the bottom cover 417 and communicates with the flow path space S. This intake opening Ani faces the surface M1 of the printing medium M supported by the rollers 201 of the transport section 2 from above.

[0047] The nozzle housing 41 also has a nozzle exhaust section 43 that protrudes downward from the bottom 416. The nozzle exhaust section 43 is located downstream Dmd from the nozzle intake section 42 and on one side Y1 of the bottom cover 417. This nozzle exhaust section 43 is offset to one side Y1 in the Y direction from the printing medium M supported by the rollers 201 of the conveyance section 2, and does not face the printing medium M. At the lower end of this nozzle exhaust section 43, an exhaust opening Ano opens downward. This exhaust opening Ano communicates with the flow path space S inside the nozzle housing 41. At the lower end of the nozzle exhaust section 43, a flange 431 is provided to surround the exhaust opening Ano.

[0048] As described above, the recovery nozzle 4 has an intake opening Ani that faces the printing medium M from above, and an exhaust opening Ano that is offset in the Y direction from the printing medium M. The intake opening Ani and the exhaust opening Ano are connected to each other via a flow path space S inside the nozzle housing 41. Therefore, as will be described later, when the exhaust opening Ano is sucked, an airflow Fn (FIGS. 5A and 5B) is formed that flows from the intake opening Ani through the flow path space S to the exhaust opening Ano.

[0049] Fig. 4 is a perspective view showing a typical internal configuration of the recovery nozzle, Figs. 5A and 5B are cross-sectional views showing a typical internal configuration of the recovery nozzle, and Fig. 6 is a diagram showing a typical operation of the recovery nozzle. The recovery nozzle 4 has a partition wall 441 arranged in the flow path space S. The partition wall 441 is provided between the side covers 411 and 412 in the transport direction Dm and extends in the Z direction. The partition wall 441 faces the side cover 411 from the downstream side Dmd and faces the side cover 412 from the upstream side Dmu.

[0050] The partition wall 441 and the side cover 411 are erected in the Z direction from both ends of the bottom 421 of the nozzle intake section 42 in the transport direction Dm, with the lower end of the partition wall 441 forming a side wall on the downstream side Dmd of the nozzle intake section 42, and the lower end of the side cover 411 forming a side wall on the upstream side Dmu of the nozzle intake section 42. An intake opening Ani is provided between the lower end of the side cover 411 and the lower end of the partition wall 441. A gap Ci is formed between the side cover 411 and the partition wall 441 in the transport direction Dm, and the intake opening Ani faces and communicates with the gap Ci from below. Furthermore, a gap Co is formed between the side cover 411 and the partition wall 441 in the transport direction Dm. The gaps Ci and Co communicate with each other above the partition wall 441. Furthermore, the nozzle exhaust section 43 is connected to the end of one side Y1 of the gap Co, so that the gap Co and the exhaust opening Ano are in communication with each other. Therefore, the airflow Fn flows from the intake opening Ani through the gap Ci and the gap Co in this order to reach the exhaust opening Ano.

[0051] The recovery nozzle 4 also has an eave 443 (FIGS. 4 and 5B) provided at the upper end 442 of the partition wall 441. The eave 443 curves upward from the upper end 442 of the partition wall 441 and protrudes toward the downstream side Dmd. That is, the eave 443 protrudes from the partition wall 441 into the gap Co. The eave 443 is provided biased toward the exhaust opening Ano (one side Y1) with respect to the upper end of the partition wall 441. That is, the eave 443 is provided in a range between positions Pa and Pb in the Y direction at the upper end 442 of the partition wall 441. Here, position Pa is the end position of the one side Y1 of the upper end 442 of the partition wall 441, and position Pb is a position between the end position of the one side Y1 and the end position of the other side Y2 of the upper end 442 of the partition wall 441 (an intermediate position in this example). Therefore, in the range where the eave 443 is not provided (FIG. 5A), the airflow Fn flowing from the gap Ci to the gap Co is not particularly restricted. On the other hand, in the range where the eaves 443 is provided (FIG. 5B), the airflow Fn flowing from the gap Ci to the gap Co is restricted by the eaves 443. As a result, as shown in FIG. 6, in the range close to the exhaust opening Ano in the Y direction, the airflow Fn is restricted by the eaves 443, but in the range far from the exhaust opening Ano in the Y direction, the airflow Fn is not restricted by the eaves 443. By providing such eaves 443, it is possible to suppress variation in the Y direction of the suction force supplied to the intake opening Ani.

[0052] 2A and 2B, the mist collection unit 3 has a plurality of exhaust ducts 5 corresponding to the plurality of collection nozzles 4, and each of the plurality of exhaust ducts 5 is connected to a corresponding collection nozzle 4. The exhaust duct 5 has an exhaust connector 51 (FIG. 7) that is connected to a flange 431 of the corresponding collection nozzle 4.

[0053] FIG. 7 is a perspective view schematically illustrating the exhaust connector of the exhaust duct. The exhaust connector 51 has a flange 511 that faces the flange 431 of the recovery nozzle 4 from below. The exhaust connector 51 also has a duct opening Adi that opens upward in the flange 511. That is, the flange 511 is provided so as to protrude laterally from the duct opening Adi. The exhaust connector 51 also has a connector pipe 512 that extends downward from the flange 511 and communicates with the duct opening Adi. The connector pipe 512 extends at an angle downward toward one side X1 in the X direction. The exhaust connector 51 also has a flange 513 provided at the lower end of the connector pipe 512. Of the flange 511 at the upper end and the flange 513 at the lower end of the exhaust duct 5, at least the flange 513 is positioned below the print medium M supported by the rollers 201 of the transport unit 2.

[0054] The exhaust duct 5 also has a stay 52 that attaches the exhaust connector 51 to the support plate 202 of the conveying unit 2. The stay 52 is attached to the support plate 202 directly or via a beam or the like. The stay 52 has a mounting plate 521 that is supported horizontally. The flange 513 of the exhaust connector 51 contacts the mounting plate 521 of the stay 52 from above and is fastened to the mounting plate 521 with screws or the like. In this way, the exhaust connector 51 of the exhaust duct 5 is attached to the support plate 202 of the conveying unit 2 via the stay 52.

[0055] The exhaust duct 5 also has an exhaust pipe 53 (FIGS. 2A and 2B) attached to the lower end of the connector pipe 512. The exhaust pipe 53 is positioned below the print medium M supported by the rollers 201 of the conveyance unit 2. A through hole that opens to the connector pipe 512 is provided in the mounting plate 521, and the upper end of the exhaust pipe 53 is attached to the lower end of the connector pipe 512 from below through the through hole. In this way, the exhaust pipe 53 extends downward from the lower end of the connector pipe 512. The exhaust pipe 53 communicates with the duct opening Adi via the connector pipe 512.

[0056] 2B, the mist collection unit 3 further includes a mist suction and capture section 6. The mist suction and capture section 6 is disposed below the print medium M supported by the rollers 201 of the transport section 2.

[0057] The mist collection unit 3 has a junction pipe 61 that joins two of the exhaust ducts 5 that correspond to the respective collection nozzles 4. For example, one junction pipe 61 is provided for two exhaust ducts 5 that correspond to two collection nozzles 4 arranged for the ejection head 121 that ejects yellow ink and the ejection head 121 that ejects magenta ink. Also, one junction pipe 61 is provided for two exhaust ducts 5 that correspond to two collection nozzles 4 arranged for the ejection head 121 that ejects cyan ink and the ejection head 121 that ejects black ink.

[0058] Therefore, in this example, two junction pipes 61 are provided. Meanwhile, the mist collection unit 3 has two vacuum flows 62 corresponding to the two junction pipes 61. In other words, the junction pipes 61 connect the two exhaust ducts 5 and the vacuum flows 62 to communicate with each other.

[0059] FIG. 8A is a cross-sectional view schematically illustrating the configuration of a vacuum flow. As shown in FIG. 8A, the vacuum flow 62 has a vacuum pipe 621. The vacuum pipe 621 has a pipe main body 622 and a vacuum flow path 623 that penetrates the pipe main body 622 in the recovery direction Dc. An intake port 624 is provided at the upstream end of the vacuum flow path 623 in the recovery direction Dc, and an exhaust port 625 is provided at the downstream end of the vacuum flow path 623 in the recovery direction Dc. In this way, the vacuum flow path 623 extends from the intake port 624 to the exhaust port 625 in the recovery direction Dc, and the intake port 624 and the exhaust port 625 are connected by the vacuum flow path 623.

[0060] Furthermore, the vacuum flow 62 has a gas supply hole 626 that opens in the outer wall of the vacuum pipe 621 and a slit 627 that connects the gas supply hole 626 to the vacuum flow path 623. The slit 627 opens to the vacuum flow path 623 between the intake port 624 and the exhaust port 625. For example, when pressurized gas Gp is ​​supplied to the gas supply hole 626 from a utility source used in the facility where the printing apparatus 1 is installed, the slit 627 injects the pressurized gas Gp into the vacuum flow path 623 toward the exhaust port 625 (i.e., downstream in the recovery direction Dc). This generates a negative pressure in the vacuum flow path 623 on the intake port 624 side relative to the slit 627, and this negative pressure generates a recovery airflow Fc. The recovery airflow Fc passes through the vacuum flow 62 in the recovery direction Dc from the intake port 624 to the exhaust port 625. To explain the mechanism by which the recovered airflow Fc is generated in more detail, when the pressurized gas Gp is ​​injected toward the exhaust port 625 side of the vacuum flow path 623 through the slit 627, the pressurized gas Gp expands and its flow rate increases rapidly. As the flow rate of the pressurized gas Gp increases, the pressure decreases on the intake port 624 side of the slit 627 in the vacuum flow path 623, generating a suction flow. The combination of this suction flow and the discharge flow of the pressurized gas Gp generates the recovered airflow Fc.

[0061] The above-mentioned junction pipe 61 is attached to an intake port 624 of the vacuum flow 62. The mist collection unit 3 also has a mist capture section 63 attached to an exhaust port 625 of the vacuum flow 62.

[0062] 8B is a cross-sectional view schematically illustrating the configuration of the mist trapping unit. The mist trapping unit 63 has a filter accommodating body 631, and a filter accommodating space 632 is provided inside the filter accommodating body 631. The mist trapping unit 63 also has an inlet 633 provided at the upstream end of the filter accommodating body 631 in the recovery direction Dc and an outlet 634 provided at the downstream end of the filter accommodating body 631. The filter accommodating space 632 extends in the recovery direction Dc from the inlet 633 to the outlet 634. The filter accommodating space 632 has a tapered portion 632a whose cross-sectional area increases from the inlet 633 toward the downstream side in the recovery direction Dc, and a large-diameter portion 632b that extends downstream in the recovery direction Dc from the tapered portion 632a and has a constant cross-sectional area. Here, the cross-sectional area refers to the area of ​​a cross section in a direction perpendicular to the recovery direction Dc. The inlet 633 is provided at the upstream end of the tapered portion 632a in the recovery direction Dc. The outlet 634 is provided at the downstream end of the large diameter portion 632b in the recovery direction Dc. The outlet 634 is the downstream end of the mist trapping portion 63 in the recovery direction Dc and is open to atmospheric pressure.

[0063] A filter 31 for capturing mist is detachably attached to a filter mounting portion 635 provided in the large diameter portion 632b of the filter storage space 632. The filter mounting portion 635 is provided so that the downstream end of the filter 31 arranged in the filter mounting portion 635 is located at the outlet 634 (i.e., the downstream end of the mist capturing portion 63) in the recovery direction Dc. In other words, the outlet 634 is located at the downstream end of the filter mounting portion 635. The cross-sectional area (effective cross-sectional area) of this filter 31 is larger than the cross-sectional area of ​​the vacuum flow path 623 of the vacuum flow 62.

[0064] The inlet 633 of the mist trapping unit 63 is attached to the exhaust port 625 of the vacuum flow 62. Therefore, the recovery airflow Fc in the recovery direction Dc generated by the vacuum flow 62 flows from the inlet 633 into the filter housing space 632 in the mist trapping unit 63, and then passes through the filter 31 in the recovery direction Dc. In this way, the ink mist contained in the recovery airflow Fc is captured by the filter 31.

[0065] 8C is a block diagram showing the configuration of the mist collection unit. As described above, the two exhaust pipes 53 extending from the two collection nozzles 4 are connected to the intake port 624 of the vacuum flow 62 via the junction pipe 61. A mist capture unit 63 is attached to the exhaust port 625 of the vacuum flow 62, and a filter 31 is disposed in the filter storage space 632 of the mist capture unit 63. The vacuum flow 62 generates an airflow from the intake port 624 to the exhaust port 625 in response to the supply of pressurized gas Gp. As a result, a collection airflow Fc is generated along a collection path Pc that flows from the collection nozzle 4 through the intake port 624 into the vacuum flow path 623 and then flows out from the exhaust port 625. A filter 31 is attached to the most downstream end of the collection path Pc, and the filter 31 captures the ink mist contained in the collection airflow Fc traveling along the collection path Pc.

[0066] The mist collection unit 3 also has a gas supply unit 7 that supplies pressurized gas Gp to the gas supply holes 626 of the vacuum flow 62. The gas supply unit 7 has a system 71c that supplies pressurized gas Gp to the collection nozzles 4 for the ejection heads 121 that eject color inks, and a system 71w that supplies pressurized gas Gp to the collection nozzles 4 for the ejection heads 131 that eject white ink. Because the system 71c and the system 71w have a common basic configuration, FIG. 8C mainly shows the system 71c, with part of the system 71w omitted.

[0067] The gas supply unit 7 has a pipe 72 that sends pressurized gas Gp from the utility to each of the system 71c and the system 71w. Meanwhile, each of the system 71c and the system 71w has a regulator 73 connected to the pipe 72, and the regulator 73 reduces the pressure of the pressurized gas Gp supplied from the utility via the pipe 72.

[0068] Furthermore, system 71c is provided with a solenoid valve 74 and a pipe 75 connecting regulator 73 and solenoid valve 74. The pipe 75 supplies pressurized gas Gp depressurized by regulator 73 to the solenoid valve 74. A solenoid valve 74 is provided for each of the two vacuum flows 62 (FIG. 2B), and the pipe 75 supplies pressurized gas Gp depressurized by regulator 73 to each solenoid valve 74. Furthermore, gas supply unit 7 has a pipe 76 connecting solenoid valve 74 and gas supply hole 626 of vacuum flow 62. In this way, regulator 73, which depressurizes pressurized gas Gp, is connected to gas supply hole 626 of vacuum flow 62 via solenoid valve 74.

[0069] Furthermore, the mist collection unit 3 has a control unit 81 that controls the mist suction capture unit 6. This control unit 81 is, for example, a processor, and controls the opening and closing of the solenoid valve 74. When the control unit 81 closes the solenoid valve 74, pressurized gas Gp is ​​not supplied to the gas supply hole 626, and a collection airflow Fc along the collection path Pc is not generated. On the other hand, when the control unit 81 opens the solenoid valve 74, pressurized gas Gp is ​​supplied to the gas supply hole 626, and a collection airflow Fc along the collection path Pc is generated. Therefore, the ink mist sucked by the collection nozzle 4 from the intake opening Ani is collected up to the filter 31 by the collection airflow Fc.

[0070] The mist collection unit 3 also has a pressure gauge 82 that detects the pressure of the collection airflow Fc before it flows out of the collection nozzle 4 and into the vacuum flow 62. The control unit 81 issues a warning to the operator in accordance with the pressure detected by the pressure gauge 82. That is, the mist collection unit 3 has a UI 83 (user interface) that is configured with a display or the like. In response to this, when the pressure detected by the pressure gauge 82 is lower than the lower limit pressure, the control unit 81 causes the UI 83 to display a screen that warns of the possibility of clogging in the collection nozzle 4. Alternatively, when the pressure detected by the pressure gauge 82 is higher than the upper limit pressure, the control unit 81 causes the UI 83 to display a screen that warns of the possibility of clogging in the filter 31.

[0071] 2A, the printing device 1 is equipped with a lifting drive mechanism 17 that raises and lowers the base frame 14 that fixes the recovery nozzle 4 to the ejection head 121. This lifting drive mechanism 17 has a lifting plate 171 to which the base frame 14 is attached, and an actuator 172 that raises and lowers the lifting plate 171. When the actuator 172 raises the lifting plate 171, the lifting plate 171 rises, taking the ejection head 121 and the recovery nozzle 4 with it. When the actuator 172 lowers the lifting plate 171, the lifting plate 171 lowers, taking the ejection head 121 and the recovery nozzle 4 with it. As a result, the operation of FIG. 9 is performed.

[0072] 9 is a partial cross-sectional view that highlights and schematically illustrates the operations performed by raising and lowering the discharge head and recovery nozzle. As shown in FIG. 9, the discharge head 121 is driven in the Z direction by the actuator 172 between a print height Hhl and a non-print height Hhh that is higher than the print height Hhl (in other words, farther from the print medium M). The flange 431 is also driven in the Z direction by the actuator 172 between a proximity height Hnl and a separation height Hnh that is higher than the proximity height Hnl (in other words, farther from the flange 511).

[0073] During image printing, in which the ejection head 121 ejects color inks onto the print medium M to print a color image, the actuator 172 lowers the ejection head 121 and the recovery nozzle 4. As a result, as shown in the "During Image Printing" section of FIG. 9 , the ejection head 121 is positioned at the printing height Hhl and ejects ink onto the print medium M while facing the print medium M supported by the roller 201 from above. During this image printing, the flange 431 of the recovery nozzle 4 is positioned at the proximity height Hnl and faces the flange 511 from above. As a result, the exhaust opening Ano faces the duct opening Adi at the proximity height Hnl. The control unit 81 also opens the solenoid valve 74 to generate the recovery airflow Fc in the vacuum flow 62. At this time, the flanges 431 and 511 at the proximity height Hnl are separated from each other, leaving a gap between them in the Z direction. Therefore, a gap also exists in the Z direction between the exhaust opening Ano and the duct opening Adi at the proximity height Hnl. However, because this gap is very small, the negative pressure (suction force) generated by the vacuum flow 62 is sufficiently transmitted to the exhaust opening Ano, generating a recovery airflow Fc. As a result, the ink mist generated during image printing is collected by the recovery airflow Fc from the intake opening Ani of the recovery nozzle 4 into the filter 31.

[0074] During non-image printing, when the ejection head 121 is not printing a color image, the actuator 172 raises the ejection head 121 and the recovery nozzle 4. As a result, as shown in the "Non-Image Printing" column in Fig. 9, the ejection head 121 is positioned at a non-printing height Hhh and separated upward from the print medium M supported by the roller 201. During this non-image printing, the flange 431 of the recovery nozzle 4 is positioned at a separation height Hnh and separated upward from the flange 511.

[0075] In the above example, no particular member is provided between the flange 431 of the nozzle exhaust portion 43 and the flange 511 of the exhaust connector 51. Alternatively, a buffer material 32 (FIGS. 10 and 11) may be provided between them.

[0076] Fig. 10 is a perspective view showing the external appearance of the buffer material, and Fig. 11 is a partial cross-sectional view showing the operation performed by raising and lowering the discharge head and recovery nozzle in a configuration equipped with the buffer material. The only difference between the operation example in Fig. 9 and the operation example in Fig. 11 is the presence or absence of the buffer material 32, so this difference will be mainly explained, and the same parts will be assigned the same reference numerals and explanations thereof will be omitted as appropriate.

[0077] The cushioning material 32 is made of sponge or rubber and is configured with a frame 321 that surrounds a communication opening A32 that penetrates in the Z direction. In other words, the communication opening A32 is provided in the center of the cushioning material 32. The cushioning material 32 is provided between the flange 431 and the flange 511 and is adhered to the bottom surface of the flange 431. When the flange 431 is positioned at the separation height Hnh during non-image printing, the cushioning material 32 is separated upward from the flange 511.

[0078] On the other hand, when the flange 431 is positioned at the proximity height Hnl during image printing, the cushioning material 32 comes into contact with the upper surface of the flange 511. In particular, the cushioning material 32 comes into contact with both the bottom surface of the flange 431 and the upper surface of the flange 511, and is crushed and deformed by the flanges 431 and 511 in the Z direction. In other words, the cushioning material 32 fills the gap between the flanges 431 and 511. During this image printing, the communication opening A32 faces the exhaust opening Ano from below and faces the duct opening Adi from above, and the exhaust opening Ano and the duct opening Adi communicate with each other via the communication opening A32.

[0079] As described above, when printing an image, the control unit 81 causes the vacuum flow 62 to generate the recovery airflow Fc. At this time, the negative pressure (suction force) supplied to the duct opening Adi by the vacuum flow 62 is transmitted to the exhaust opening Ano via the communication opening A32, generating the recovery airflow Fc. As a result, the ink mist generated when printing an image is collected by the recovery airflow Fc from the intake opening Ani of the recovery nozzle 4 to the filter 31.

[0080] According to the embodiment described above, the recovery airflow Fc for sucking ink mist from the recovery nozzle 4 and recovering the ink mist is generated by the vacuum flow 62 (airflow generating piping). This vacuum flow 62 has a slit 627 (supply port) that opens into the vacuum flow path 623 (piping flow path) between the intake port 624 and the exhaust port 625. The slit 627 injects pressurized gas Gp into the vacuum flow path 623 toward the exhaust port 625, generating a negative pressure on the intake port 624 side of the slit 627 of the vacuum flow path 623, and this negative pressure generates the recovery airflow Fc. This recovery airflow Fc is generated along the recovery path Pc, which flows from the recovery nozzle 4 through the intake port 624 into the vacuum flow path 623 and then flows out from the exhaust port 625. In other words, the recovery airflow Fc can be generated simply by supplying the pressurized gas Gp, which is prepared by equipment (e.g., utility) separate from the printing device 1, to the slit 627 of the vacuum flow 62. Such a vacuum flow 62 does not have any electronic components, which makes it possible to prevent breakdowns in the mechanism (vacuum flow 62) that generates the airflow for collecting the ink mist.

[0081] Furthermore, this embodiment can also achieve the following effects. Specifically, the vacuum flow 62 has a simple configuration that does not include any electronic components. Therefore, cleaning of the vacuum flow 62 to which ink mist has adhered can be easily performed. Also, while suction fans and vacuum pumps generate vibrations as they rotate, the vacuum flow 62 does not generate vibrations. Therefore, the ejection of ink from the ejection heads 121 and 131 can be stabilized without causing vibrations to the ejection heads 121 and 131.

[0082] This embodiment can also be suitably applied to a printing device 1 equipped with a filter 31 disposed on the recovery path Pc to capture ink mist contained in the recovery airflow Fc traveling along the recovery path Pc. In other words, when a suction fan or vacuum pump is used to generate the recovery airflow Fc, the filter 31 must be disposed upstream of the suction fan or vacuum pump to prevent ink mist from adhering to the suction fan or vacuum pump. In contrast, this embodiment prevents problems such as breakdowns and cleaning due to ink mist adhering to the vacuum flow 62. Therefore, the filter 31 can be positioned either downstream or upstream of the vacuum flow 62. This increases the flexibility in the placement of the filter 31.

[0083] Furthermore, the filter 31 is disposed downstream of the exhaust port 625 in the recovered airflow Fc, and the recovered airflow Fc passes through the filter 31 after flowing out of the exhaust port 625. In this configuration, the filter 31 is disposed relatively far from the printing medium M. This prevents the printing medium M from being contaminated by ink scattered from the filter 31 during maintenance work such as cleaning or replacing the filter 31. Furthermore, since there is relatively more space downstream of the exhaust port 625, a large filter 31 can be easily disposed.

[0084] Also, the collection path Pc is provided with a mist capture section 63 (mist exhaust duct) that is connected to the exhaust port 625 from the downstream side and communicates with the exhaust port 625. The mist capture section 63 has a filter arrangement section 635 in which a filter 31 is arranged. The filter 31 arranged in the filter arrangement section 635 captures ink mist contained in the collection airflow Fc that flows out from the exhaust port 625 and travels through the mist capture section 63.

[0085] In this case, the cross-sectional area of ​​the filter 31 is larger than the cross-sectional area of ​​the vacuum flow path 623 of the vacuum flow 62. This reduces the frequency of maintenance work such as cleaning and replacing the filter 31. In addition, the average flow velocity of the gas passing through the filter 31 can be kept slow, allowing the use of various filters 31.

[0086] The filter arrangement section 635 is provided at the end of the recovery path Pc downstream of the mist capture section 63, and is open toward the downstream side of the recovery path Pc. Thus, in the recovery path Pc, the downstream end of the filter arrangement section 635 is open to atmospheric pressure, and the filter 31 is arranged in this filter arrangement section 635. By arranging the filter 31 in this manner, it is possible to reduce loss of negative pressure generated by the vacuum flow 62 to generate the recovery airflow Fc. As a result, the recovery airflow Fc can be reliably generated, and the ink mist can be efficiently collected.

[0087] 12A and 12B are diagrams showing the loss of negative pressure caused by a vacuum flow. In the example of FIG. 12A, the filter 31 is provided upstream of the vacuum flow 62 in the recovery direction Dc. In the example of FIG. 12B, the filter 31 is provided downstream of the vacuum flow 62 in the recovery direction Dc, and in particular, the filter 31 is open to atmospheric pressure at its downstream end in the recovery direction Dc. In both figures, the cross-sectional area A1 corresponds to the cross-sectional area of ​​the vacuum flow path 623 of the vacuum flow 62, and the cross-sectional area A2 corresponds to the cross-sectional area of ​​the filter 31.

[0088] where: Flow path cross-sectional area A1 = 0.000133 (m 2 ) ·Flow path cross-sectional area A2=0.0933(m 2 ) Average flow velocity U1 upstream of the vacuum flow = 50.2 (m / s) Average flow velocity downstream of the vacuum flow: U2 = 62.8 (m / s) Average flow velocity U1F upstream of the filter = 0.0715 (m / s) Average flow velocity downstream of the filter U2F = 0.0894 (m / s) Air density ρ = 1.293 (kg / m 3 ) The pressure loss was calculated under the following conditions.

[0089] In the example of Figure 12A, Rapid expansion pipe pressure loss ΔPa1=1626(Pa) Sudden contraction pipe pressure loss ΔPa2=669(Pa) Pipe outlet pressure loss ΔPa3 = 2548 (Pa) Total pressure loss ΔPa = 4843 (Pa) It is calculated as follows.

[0090] In the example of Figure 12B, Rapid expansion pipe pressure loss ΔPb1=2541(Pa) Pipe outlet pressure loss ΔPb2=0(Pa) Total pressure loss ΔPb=2541(Pa) It is calculated as follows.

[0091] As a result, it can be seen that pressure loss can be effectively suppressed by arranging filter 31 as shown in the example of Fig. 12B. In other words, from the viewpoint of suppressing pressure loss, it can be said that the arrangement of filter 31 shown in Fig. 8B is extremely suitable.

[0092] Furthermore, in the above embodiment, a pressure gauge 82 (pressure detection unit) is provided to detect the pressure in the recovered airflow Fc at a position between the recovery nozzle 4 and the vacuum flow 62. This makes it possible to check whether there is an abnormality in the pressure.

[0093] In particular, a UI83 (alarm unit) is provided that issues a warning when the pressure detected by the pressure gauge 82 is outside a predetermined range (a range equal to or greater than the lower limit pressure and equal to or less than the upper limit pressure). With this configuration, if an abnormality occurs in the pressure, the operator can take appropriate action.

[0094] In the embodiment described above, the printing medium M corresponds to an example of the "printing medium" of the present invention, the transport direction Dm corresponds to an example of the "transport direction" of the present invention, the transport unit 2 corresponds to an example of the "printing medium transport unit" of the present invention, the ejection head 121 corresponds to an example of the "ejection head" of the present invention, the recovery nozzle 4 corresponds to an example of the "recovery nozzle" of the present invention, the recovered airflow Fc corresponds to an example of the "recovered airflow" of the present invention, the vacuum flow 62 corresponds to an example of the "airflow generating piping" of the present invention, the pressurized gas Gp corresponds to an example of the "pressurized gas" of the present invention, the gas supply unit 7 corresponds to an example of the "gas supply unit" of the present invention, and the intake port 624 corresponds to an example of the "intake port" of the present invention. the exhaust port 625 corresponds to an example of an "exhaust port" of the present invention, the vacuum flow path 623 corresponds to an example of a "piping flow path" of the present invention, the slit 627 corresponds to an example of a "supply port" of the present invention, the recovery path Pc corresponds to an example of a "recovery path" of the present invention, the printing device 1 corresponds to an example of a "printing device" of the present invention, the filter 31 corresponds to an example of a "filter" of the present invention, the mist capture section 63 corresponds to an example of a "mist exhaust duct" of the present invention, the filter arrangement section 635 corresponds to an example of a "filter arrangement section" of the present invention, the pressure gauge 82 corresponds to an example of a "pressure detection section" of the present invention, and the UI 83 corresponds to an example of an "alert section" of the present invention.

[0095] The present invention is not limited to the above-described embodiment, and various modifications other than those described above are possible without departing from the spirit of the present invention. For example, the filter 31 may be configured by stacking multiple types of filters. Specifically, a filter with a low filtration accuracy and a filter with a high filtration accuracy may be stacked, and the recovered airflow Fc may pass through the former filter and then the latter filter.

[0096] The position of the filter 31 can be changed as appropriate, and the filter 31 may be disposed upstream of the vacuum flow 62 in the recovery direction Dc.

[0097] Furthermore, it is not necessary to provide a junction pipe 61 to combine a plurality of exhaust ducts 5, and the use of the junction pipe 61 is not essential.

[0098] Furthermore, the flange 431 of the nozzle exhaust portion 43 and the flange 511 of the exhaust duct 5 may be connected to each other. In this case, it is preferable that the exhaust duct 5 be able to be flexibly deformed.

[0099] Furthermore, the period during which the vacuum flow 62 generates the recovery airflow Fc is not limited to when an image is being printed, and therefore the vacuum flow 62 may generate the recovery airflow Fc throughout both when an image is being printed and when an image is not being printed.

[0100] Furthermore, the cushioning material 32 may be bonded to the flange 511 instead of the flange 431 .

[0101] Furthermore, various materials are conceivable for the flanges 431 and 511. In other words, these materials may be resin or metal.

[0102] Furthermore, in the above embodiment, each of the multiple recovery nozzles 4 is disposed downstream of the corresponding ejection head 121 in the transport direction Dm, but this is not limiting. For example, there is a possibility that the ink mist may scatter to a location other than the downstream side of the ejection head 121 in the transport direction Dm. In order to collect such ink mist, each of the multiple recovery nozzles 4 may be disposed near the corresponding ejection head 121.

[0103] In the above embodiment, the regulator 73 may be an electropneumatic regulator. In this case, the control unit 81 may control the regulator 73 in accordance with the pressure detected by the pressure gauge 82. This configuration allows the pressurized gas Gp to be supplied at a more stable pressure, improving the stability of mist collection. For example, if the pressurized gas Gp is ​​supplied to the gas supply hole 626 from a utility power source used in the facility where the printing device 1 is installed, the pressure of the supplied pressurized gas Gp may fluctuate depending on the facility. Even in such a case, the control unit 81 controls the regulator 73 in accordance with the pressure detected by the pressure gauge 82, thereby allowing the pressurized gas Gp to be supplied at a stable pressure. Furthermore, for example, if the filter 31 becomes clogged with ink mist, sufficient suction force may not be supplied to the intake opening Ani. In this case, the pressure gauge 82 detects an abnormal pressure. Even in such a case, the control unit 81 controls the regulator 73 in accordance with the pressure detected by the pressure gauge 82 to increase or decrease the supply pressure of the pressurized gas Gp, thereby providing sufficient suction force to the intake opening Ani.

[0104] Furthermore, in the above embodiment, the pressure gauge 82 (pressure detection unit) detects the pressure at a position between the recovery nozzle 4 and the vacuum flow 62, but this is not limited to this. For example, the pressure gauge 82 (pressure detection unit) may be configured to detect the pressure at a position between the vacuum flow 62 and the filter 31. Even in this case, it is possible to check whether there is an abnormality in the pressure.

[0105] In the above embodiment, the slits 627 are provided in a portion of the circumferential direction of the vacuum flow path 623 (FIG. 8A), but this is not limiting. The slits 627 may be provided over the entire circumferential direction of the vacuum flow path 623. [Industrial Applicability]

[0106] The present invention is applicable to all techniques for collecting ink mist that is generated when ink is ejected onto a print medium to print an image. [Explanation of symbols]

[0107] 1...Printing device 121...Discharge head 2...Transport section 31...Filter 4...Recovery nozzle 62...Vacuum flow 623...Vacuum flow path 624...Intake port 625...Exhaust port 627...Slit 63...Mist capture section 635...Filter placement section 7...Gas supply section 82...Pressure gauge 83...UI Dm: Conveying direction Fc...Recovered airflow Gp: Pressurized gas M…Print media Pc…Recovery route

Claims

1. a print medium transport unit that transports the print medium in a transport direction; an ejection head that faces the print medium and ejects ink onto the print medium; a recovery nozzle disposed near the ejection head; an airflow generating pipe that generates a recovery airflow for sucking ink mist generated by the ejection head ejecting ink through the recovery nozzle and recovering the ink mist; a gas supply unit that supplies pressurized gas to the airflow generating pipe; Equipped with the airflow generating pipe has an intake port, an exhaust port, a pipe flow path extending from the intake port to the exhaust port, and a supply port opening into the pipe flow path between the intake port and the exhaust port, the gas supply unit supplies pressurized gas to the supply port, the supply port generates a negative pressure in the piping flow path on the intake port side relative to the supply port by injecting the pressurized gas supplied from the gas supply unit into the piping flow path toward the exhaust port side, and generates the recovered airflow by the negative pressure; A printing apparatus in which the recovery airflow is generated along a recovery path that flows from the recovery nozzle through the intake port into the piping flow path and then flows out from the exhaust port.

2. The printing apparatus according to claim 1 , further comprising a filter disposed in the recovery path to capture ink mist contained in the recovery airflow traveling along the recovery path.

3. the filter is disposed downstream of the exhaust port in the recovery path, 3. The printing apparatus of claim 2, wherein the recovered airflow passes through the filter after flowing out of the exhaust port.

4. The mist exhaust duct is further provided, the mist exhaust duct being connected to the exhaust port from the downstream side of the recovery path and communicating with the exhaust port. The mist exhaust duct has a filter arrangement portion in which the filter is arranged, 4. The printing apparatus according to claim 3, wherein the filter disposed in the filter arrangement portion captures ink mist contained in the recovered airflow that flows out of the exhaust port and travels through the mist exhaust duct.

5. The printing apparatus according to claim 4 , wherein the cross-sectional area of ​​the filter is larger than the cross-sectional area of ​​the pipe flow path of the airflow generating pipe.

6. The printing apparatus according to claim 4 or 5, wherein the filter arrangement portion is provided at an end of the collection path downstream of the mist exhaust duct and opens toward the downstream side of the collection path.

7. The printing apparatus according to claim 1 , further comprising a pressure detection unit that detects pressure at a position in the recovery path between the recovery nozzle and the airflow generating pipe.

8. The printing apparatus according to claim 7 , further comprising a notification unit that issues a warning when the pressure detected by the pressure detection unit is outside a predetermined range.

9. An ink mist recovery method for recovering ink mist generated by an ejection head ejecting ink onto a print medium transported in a transport direction, using a recovery nozzle disposed near the ejection head, comprising: a step of supplying pressurized gas to the airflow generating pipe in order to generate a recovery airflow by the airflow generating pipe for sucking ink mist generated by the ejection head from the recovery nozzle and recovering the ink mist; the airflow generating pipe has an intake port, an exhaust port, a pipe flow path extending from the intake port to the exhaust port, and a supply port opening into the pipe flow path between the intake port and the exhaust port, the supply port injects the pressurized gas into the piping passage toward the exhaust port, thereby generating a negative pressure in the piping passage closer to the intake port than the supply port, and generating the recovered airflow by the negative pressure; The ink mist collecting method, wherein the collecting airflow is generated along a collection path that flows from the collection nozzle through the intake port into the piping flow path and then flows out from the exhaust port.

Images