JP2019119187A - Ink mist recovery device - Google Patents

Abstract

To provide an ink mist recovery device which can reduce dropping of ink droplets onto a print medium while suppressing large-sizing thereof.SOLUTION: An ink mist recovery part comprises: a duct 66 having a mist suction opening 71 which so opens as to face a web, and extends in a width direction of the web; and a suction part which sucks air from the duct 66, and thus, sucks and recovers ink mists into the duct 66 via the mist suction opening 71. The duct 66 has grooves 72A to 74A, 72B to 74B which receive ink droplets which are formed by aggregation of ink mists sucked into the duct 66, and flows ink droplets outside the web in a width direction.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an ink mist recovery apparatus that recovers ink mist.

  In the ink jet printing apparatus, the ink mist is generated as the ink is atomized along with the discharge of the ink from the ink jet head. The ink mist may adhere to the print medium to contaminate the print. In addition, ink mist also causes contamination inside the apparatus. For this reason, in the ink jet printing apparatus, it is required to collect the ink mist.

  As a mechanism for collecting ink mist, there is known a mechanism having a duct arranged above the printing medium and a fan connected to the duct, and sucking and collecting the ink mist in the duct by driving the fan .

  In such a mechanism, ink droplets formed by aggregation of the ink mist sucked in the duct may fall on the print medium to contaminate the print. Furthermore, the contamination due to the ink droplets dropped onto the print medium may be transferred to the roller for transporting the print medium, and the ink contamination may be re-transferred from the roller to the print medium.

  As a technique for suppressing the drop of ink droplets from the duct to the print medium as described above, Patent Document 1 discloses a technique for removing ink droplets attached to the duct by a wiper.

Unexamined-Japanese-Patent No. 2005-271361

  However, when providing a wiper in a duct like the technique of patent document 1, the installation space of a wiper and the installation source of the drive source of a wiper are needed, and the enlargement of an apparatus is caused.

  The present invention has been made in view of the above, and it is an object of the present invention to provide an ink mist recovery device capable of reducing the drop of ink droplets onto a print medium while suppressing the increase in size of the device.

  In order to achieve the above object, the ink mist collecting apparatus according to the present invention collects ink mist generated along with the discharge of the ink by the ink jet head which discharges the ink onto the print medium to be transported to form an image. An apparatus, comprising: a duct having a mist suction opening which is opened facing the print medium and extends in the width direction of the print medium; and suctioning air from the duct, ink mist through the mist suction opening And a suction unit for suctioning and collecting the inside of the duct, wherein the duct receives ink droplets formed by aggregation of the ink mist sucked into the duct, and the outside of the print medium in the width direction It is characterized in that it has a groove for flowing ink droplets.

  According to the ink mist recovery apparatus of the present invention, it is possible to reduce the drop of the ink droplet onto the print medium while suppressing the increase in size of the apparatus.

FIG. 1 is a schematic configuration diagram of a printing system according to an embodiment. It is a top view which shows schematic structure of the head unit which the inkjet printing apparatus of the printing system shown in FIG. 1 has. It is a perspective view which shows schematic structure of the ink mist collection | recovery part provided in the head unit shown in FIG. It is a cross-sectional perspective view along the AA line of FIG. It is the elements on larger scale sectional view along the AA line of FIG. It is a partially broken perspective view of the duct of the ink mist collection | recovery part shown in FIG. It is a control block diagram of a printing system shown in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same or equivalent parts or components are denoted by the same or equivalent reference numerals throughout the drawings.

  The embodiment shown below exemplifies an apparatus etc. for embodying the technical idea of this invention, and the technical idea of this invention is the material, shape, structure, arrangement etc. of each component. Does not specify the following. Various changes can be added to the technical idea of the present invention within the scope of the claims.

  FIG. 1 is a schematic configuration diagram of a printing system according to an embodiment of the present invention. FIG. 2 is a plan view showing a schematic configuration of a head unit of the inkjet printing apparatus of the printing system shown in FIG. FIG. 3 is a perspective view showing a schematic configuration of an ink mist recovery unit provided in the head unit shown in FIG. FIG. 4 is a cross-sectional perspective view taken along the line AA of FIG. FIG. 5 is a partially enlarged cross-sectional view taken along the line AA of FIG. FIG. 6 is a partially broken perspective view of a duct of the ink mist recovery unit shown in FIG. FIG. 7 is a control block diagram of the printing system shown in FIG. In the following description, the direction orthogonal to the paper surface of FIG. 1 is referred to as the front-rear direction, and the front direction of the paper surface is referred to as the front. Further, the top, bottom, left, and right of the paper surface in FIG. 1 are referred to as the top, bottom, left, and right directions.

  As shown in FIGS. 1 and 7, the printing system 1 according to the present embodiment includes an unwinding device 2, an inkjet printing device 3, and a winding device 4.

  The unwinding device 2 unwinds the web W, which is a long printing medium made of film, paper or the like, to the inkjet printing device 3. The unwinding device 2 includes a web roll support shaft 11, a brake 12, and an unwinding device control unit 13.

  The web roll support shaft 11 rotatably supports the web roll 16. The web roll 16 is a web W wound in a roll.

  The brake 12 applies a brake to the web roll support shaft 11. Thus, tension is applied to the web W between the web roll 16 and the transport roller 43 of the inkjet printing apparatus 3 described later.

  The unwinding device control unit 13 controls the brake 12. The unwinding device control unit 13 is configured to include a CPU, a memory, a hard disk, and the like.

  The inkjet printing apparatus 3 prints an image on the web W while conveying the web W unwound from the web roll 16. The inkjet printing apparatus 3 includes a transport unit 21, printing units 22A and 22B, and a printing apparatus control unit 23. The suffixes of the alphabets in the reference numerals of the printing units 22A, 22B, etc. may be omitted and collectively described.

  The transport unit 21 transports the web W unwound from the web roll 16. The conveyance unit 21 includes guide rollers 31 to 40, twenty head lower rollers 41, a meander control unit 42, a pair of conveyance rollers 43, and a conveyance motor 44.

  The guide rollers 31 to 40 guide the web W conveyed in the ink jet printing apparatus 3. The guide rollers 31 to 40 are driven to rotate by the web W being conveyed.

  The guide rollers 31, 32 guide the web W between the unwinding device 2 and the meander control unit 42. The guide roller 31 is disposed at the lower left end of the inkjet printing apparatus 3. The guide roller 32 is disposed between the guide roller 31 and a meander control roller 46 of a meander control unit 42 described later.

  The guide rollers 33 to 39 guide the web W between the meander control unit 42 and the conveyance roller 43. The guide roller 33 is disposed slightly above the left of the meander control roller 47 of the meander control unit 42 described later. The guide roller 34 is disposed above the guide roller 33. The guide roller 35 is disposed at the same height as the guide roller 34 and to the right of the guide roller 34. The guide roller 36 is disposed below the guide roller 35 and higher than the guide roller 33. The guide roller 37 is disposed on the left side of the guide roller 36 and in the vicinity of the right side of the web W between the guide rollers 33 and 34 and at a position substantially the same height as the guide roller 36. The guide roller 38 is disposed at the lower right of the guide roller 37. The guide roller 39 is disposed below and slightly to the right of the guide roller 38.

  The guide roller 40 guides the web W between the transport roller 43 and the winding device 4. The guide roller 40 is disposed at the lower right end of the ink jet printing apparatus 3.

  The head lower roller 41 supports the web W under a head unit 51 described later between the guide rollers 34 and 35 and between the guide rollers 36 and 37. Ten head lower rollers 41 are disposed between the guide rollers 34 and 35 and between the guide rollers 36 and 37, respectively. The two lower head rollers 41 are disposed immediately below each of the head units 51. The head lower roller 41 is driven to rotate by the web W being conveyed.

  The meandering control unit 42 corrects meandering, which is a change in position in the width direction (front-rear direction) orthogonal to the transport direction of the web W. The meander control unit 42 includes meander control rollers 46 and 47 and a meander control motor 48.

  The meander control rollers 46 and 47 guide the web W and correct the meander of the web W. The meandering control rollers 46 and 47 are driven to rotate by the web W being conveyed. The meandering control rollers 46 and 47 rotate in the width direction of the web W by tilting so as to be inclined with respect to the width direction of the web W when viewed from the left-right direction, thereby correcting the meandering. The meandering control roller 46 is disposed to the right of the guide roller 32. The meander control roller 47 is disposed above the meander control roller 46.

  The meandering control motor 48 rotates the meandering control rollers 46 and 47 around a rotation axis parallel to the left and right direction.

  The pair of transport rollers 43 transports the web W toward the winding device 4 while nipping the web W. The pair of conveyance rollers 43 is disposed between the guide rollers 39 and 40.

  The conveyance motor 44 rotationally drives the conveyance roller 43.

  The printing units 22A and 22B print images on the front and back surfaces of the web W, respectively. The printing unit 22A is disposed in the vicinity of the upper side of the web W between the guide rollers 34 and 35. The printing unit 22 </ b> B is disposed in the vicinity of the upper side of the web W between the guide rollers 36 and 37. The printing units 22A and 22B each include five head units 51.

  As shown in FIGS. 2 and 7, the head unit 51 includes an ink jet head 56 and an ink mist collecting unit 57 (corresponding to the ink mist collecting device in the claims). FIG. 2 shows the head unit 51 of the printing unit 22A. The head unit 51 of the printing unit 22A and the head unit 51 of the printing unit 22B have the same configuration except that the positional relationship between the inkjet head 56 and the ink mist collecting unit 57 in the conveyance direction (left and right direction) of the web W is reversed. It is.

  The ink jet head 56 ejects ink onto the web W being conveyed to print an image. In the printing unit 22, the inkjet heads 56 of the five head units 51 eject ink of different colors. The inkjet head 56 has a plurality of head modules 61. In the present embodiment, as shown in FIG. 2, the ink jet head 56 has ten head modules 61.

  In the ink jet head 56, ten head modules 61 are arranged in a zigzag along the front-rear direction. Specifically, the ten head modules 61 are arranged in the front-rear direction, and are alternately arranged at every other position in the transport direction (left-right direction) of the web W.

  The ink mist recovery unit 57 recovers the ink mist generated as the ink is ejected by the inkjet head 56. As shown in FIGS. 2 and 3, the ink mist recovery unit 57 includes a duct 66, ink receiving portions 67A and 67B, a suction path portion 68, and a suction portion 69.

  The duct 66 is a member for sucking the ink mist together with the air on the upper side of the web W. The duct 66 is formed in a box shape extending along the width direction (front-rear direction) of the web W. The length of the duct 66 (length in the front-rear direction) is larger than the width of the web W. The duct 66 projects near the downstream side of the ink jet head 56 with the front end of the duct 66 projecting forward beyond the front side of the web W, and the rear end of the duct 66 projects rearward relative to the rear side of the web W It is arranged to be.

  Here, in the head unit 51 of the printing unit 22A, since the right side of the inkjet head 56 is the downstream side, the duct 66 is disposed on the right side of the inkjet head 56 as shown in FIG. In the head unit 51 of the printing unit 22B, since the left side of the ink jet head 56 is the downstream side, the duct 66 is disposed on the left side of the ink jet head 56, contrary to FIG.

  The duct 66 is opened opposite to the web W and has a mist suction opening 71 extending in the front-rear direction. The mist suction opening 71 is formed over substantially the entire length of the duct 66. The front end of the mist suction opening 71 is positioned forward of the front side of the web W, and the rear end of the mist suction opening 71 is positioned rearward of the rear side of the web W.

  Grooves 72A to 74A and 72B to 74B extending in the front-rear direction are formed in the duct 66. The grooves 72A to 74A and 72B to 74B are formed over substantially the entire length of the duct 66. The grooves 72A to 74A are formed in the lower portion of the right inner wall 66a of the duct 66. The grooves 72A to 74A are formed by digging the inner wall 66a from the surface. The grooves 72B to 74B are formed in the lower part of the left inner wall 66b of the duct 66. The grooves 72B to 74B are formed by digging the inner wall 66b from the surface. The grooves 72A to 74A and 72B to 74B receive the ink droplets formed by the aggregation of the ink mist sucked into the duct 66 and flow the ink droplets to the outside of the web W in the front-rear direction.

  The grooves 72A to 74A are inclined relative to the horizontal so that they become lower toward the front side, and the front ends of the grooves 72A to 74A are located forward of the front side of the web W. Thus, the grooves 72A to 74A can flow ink droplets to the front outside of the web W. Further, the grooves 72B to 74B are inclined with respect to the horizontal so as to be lower toward the rear side, and the rear ends of the grooves 72B to 74B are located more rearward than the rear side of the web W. Thus, the grooves 72B to 74B can allow ink droplets to flow to the rear outside of the web W.

  The grooves 72 to 74 differ in width Y and depth D from each other. Specifically, the groove 73A is smaller in width Y and depth D than the groove 72A, and the groove 74A is smaller in width Y and depth D than the groove 73A. The groove 73B is smaller in width Y and depth D than the groove 72B, and the groove 74B is smaller in width Y and depth D than the groove 73B.

  The width Y and the depth D of the grooves 72 to 74 are different from each other in order to cope with the change in the surface tension of the ink due to the change in the type of the ink ejected by the ink jet head 56. For example, when the ink jet head 56 is changed from the one which discharges the oil-based ink to the one which discharges the water-based ink, the surface tension of the ink which the ink jet head 56 discharges changes. As described above, the grooves 72 to 74 having different widths Y and depth D are provided because the width Y and the depth D of the grooves to which the ink droplets easily flow are different due to the difference in the surface tension of the ink. There is. Thus, the ink droplets are prevented from falling without flowing into the grooves 72 to 74.

  Further, the duct 66 has a partition plate 76 which divides the inside of the duct 66 into upper and lower parts. A lower area 77 which is a lower area of the duct 66 partitioned by the partition plate 76 is an area in which the mist suction opening 71 and the grooves 72 to 74 are formed. An upper area 78, which is an upper area of the duct 66 partitioned by the partition plate 76, is an area in which a suction port 79 for suctioning air from the duct 66 through the suction path 68 is formed.

  The partition plate 76 is provided in order to equalize the suction air velocity to the duct 66 in the front-rear direction. The partition plate 76 is formed with a plurality of partition plate openings 81 communicating the areas partitioned by the partition plate 76. That is, the lower area 77 and the upper area 78 are communicated by the partition plate opening 81. When the suction unit 69 is driven, air sucked into the duct 66 from the mist suction opening 71 flows from the lower area 77 to the upper area 78 through the partition plate opening 81, and the upper area through the suction port 79. It flows from 78 to the suction path 68. The plurality of partition plate openings 81 are disposed along the front-rear direction. The plurality of partition plate openings 81 are formed such that the area of the openings increases as the distance from the suction port 79 increases.

  Here, in the present embodiment, the suction port 79 of the duct 66 is formed at the central portion of the duct 66 in the front-rear direction. For this reason, on the front side of the central portion of the partition plate 76, as shown in FIG. 6, the opening area of the partition plate opening 81 increases as it goes to the front. Further, on the rear side of the central portion of the partition plate 76, the opening area of the partition plate opening 81 increases as it goes to the rear. Thereby, equalization | homogenization in the front-back direction of the suction wind speed to the duct 66 is achieved.

  The ink receiving portion 67A receives ink droplets which are guided to the front outside of the web W by the grooves 72A to 74A and fall from the front end of the duct 66. The ink receiving portion 67 </ b> B receives ink droplets which are guided by the grooves 72 </ b> B to 74 </ b> B to the rear outside of the web W and fall from the rear end of the duct 66.

  The suction path portion 68 connects the duct 66 and the suction portion 69, and constitutes a path of air flowing from the duct 66 to the suction portion 69. The suction path 68 includes a connection pipe 86 connected to the duct 66 and a tube 87 connecting the connection pipe 86 and the suction part 69. The connection pipe portion 86 communicates with the duct 66 via the suction port 79 of the duct 66.

  The suction unit 69 sucks the air from the duct 66 through the suction path unit 68, thereby sucking and collecting the ink mist together with the air into the duct 66 through the mist suction opening 71. The suction unit 69 includes a fan and the like.

  The printing apparatus control unit 23 controls the operation of each unit of the inkjet printing apparatus 3. The printing device control unit 23 includes a CPU, a RAM, a ROM, a hard disk, and the like.

  The winding device 4 winds up the web W printed by the inkjet printing device 3. The winding device 4 includes a winding shaft 91, a winding motor 92, and a winding device control unit 93.

  The winding shaft 91 winds and holds the web W.

  The winding motor 92 rotates the winding shaft 91 clockwise in FIG. The web W is wound around the winding shaft 91 by the rotation of the winding shaft 91.

  The winding device control unit 93 controls the driving of the winding motor 92. The winding device control unit 93 includes a CPU, a RAM, a ROM, a hard disk, and the like.

  Next, the operation of the printing system 1 will be described.

  When printing is performed by the printing system 1, when a print job is input, the printing device control unit 23 starts driving of the conveyance motor 44, and the winding device control unit 93 starts driving of the winding motor 92. Thereby, the transport of the web W from the unwinding device 2 toward the winding device 4 is started. After the start of the transport of the web W, when the transport speed of the web W reaches a predetermined printing transport speed, the unwinding device control unit 13 starts the driving of the brake 12. When the web roll support shaft 11 is braked by the brake 12, the web W is transported while tension is applied to the web W between the web roll 16 and the transport roller 43. In addition, after the transport speed of the web W reaches the printing transport speed, the printing apparatus control unit 23 controls the transport motor 44 to maintain the printing transport speed.

  After starting constant-velocity conveyance at the printing conveyance speed of the web W, the printing apparatus control unit 23 controls the respective inkjet heads 56 of the printing units 22A and 22B to print an image on the web W based on the print job.

  Further, the printing apparatus control unit 23 drives the suction units 69 of the ink mist collecting units 57 of the printing units 22A and 22B.

  When ink is ejected from the nozzles by driving the inkjet head 56, ink mist is generated. Most of the generated ink mist flows from the ink jet head 56 to the downstream side by the transport air flow generated by the transport of the web W. The ink mist recovery unit 57 sucks the ink mist flowing downstream from the ink jet head 56 into the duct 66 through the mist suction opening 71.

  A part of the ink mist sucked into the duct 66 adheres to the inner walls 66 a, 66 b and the like in the duct 66. When the ink mist adhering to the inner walls 66a, 66b, etc. accumulates, the ink mist aggregates to form ink droplets. When the ink droplets formed in the duct 66 descend along the inner walls 66a and 66b and flow into any of the grooves 72A to 74A and 72B to 74B, the ink droplets are guided to the outside of the web W. That is, the ink droplets having flowed into the grooves 72A to 74A flow forward along the grooves 72A to 74A and drop from the mist suction opening 71 at the front end of the duct 66. The ink dropped from the front end of the duct 66 is received by the ink receiving portion 67A. Further, the ink droplets having flowed into the grooves 72B to 74B flow rearward along the grooves 72B to 74B, and drop from the mist suction opening 71 at the rear end of the duct 66. The ink dropped from the rear end of the duct 66 is received by the ink receiving portion 67B.

  When printing based on the print job is finished, the unwinding device control unit 13 stops the brake 12, the printing device control unit 23 stops the conveyance motor 44, and the winding device control unit 93 stops the winding motor 92. In addition, the printing apparatus control unit 23 stops the suction unit 69 of each of the ink mist collecting units 57 of the printing units 22A and 22B. Thus, the transport of the web W is completed, and a series of operations are completed.

  As described above, in the ink mist collecting unit 57 of the inkjet printing apparatus 3, the duct 66 receives the ink droplets formed by the aggregation of the ink mist, and the grooves 72A through which the ink droplets flow to the outside of the web W 74A, 72B to 74B. This reduces the drop of ink droplets on the web W. Further, since the ink droplets are guided to the outside of the web W by the grooves 72A to 74A and 72B to 74B formed in the inner walls 66a and 66b of the duct 66, the enlargement of the apparatus can be suppressed. Therefore, according to the ink mist collecting unit 57, it is possible to reduce the drop of the ink droplet to the print medium while suppressing the enlargement of the apparatus.

  Further, in the duct 66, grooves 72 to 74 having mutually different widths Y and depths D are formed. As a result, even if the surface tension of the ink used in the ink jet head 56 changes, the ink droplets can be reduced without flowing into the grooves 72 to 74. Therefore, the drop of the ink droplet on the print medium can be further reduced.

  Further, in the duct 66, the plurality of partition plate openings 81 are formed so as to increase in opening area as they move away from the suction port 79. Thereby, the nonuniformity of the suction | inhalation wind speed by the duct 66 in the width direction of the web W can be suppressed. As a result, it is possible to suppress the nonuniformity of the suction performance of the ink mist by the duct 66 in the width direction of the web W.

  In the above embodiment, the grooves 72A to 74A are inclined to be lower toward the front side, and the grooves 72B to 74B are inclined to be lower toward the rear side. Is not limited to this. For example, the groove of the duct 66 may be inclined such that the front side of a predetermined position (for example, the center) in the front-rear direction is lower toward the front side, and the rear side of the predetermined position is inclined toward the rear side.

  In the above-described embodiment, the grooves 72 to 74 have different widths Y and depths D, but any one of the widths Y and depths D may be different from each other. Even in this case, it is possible to cope with the change in the surface tension of the ink used in the ink jet head 56 by appropriately setting the width Y and the depth D of each groove.

  Moreover, in the above-mentioned embodiment, although six groove | channels of groove | channel 72A-74A, 72B-74B were formed, the number of grooves is not restricted to this.

  The present invention is not limited to the above embodiment as it is, and in the implementation stage, the constituent elements can be modified and embodied without departing from the scope of the invention. In addition, various inventions can be formed by appropriate combinations of a plurality of components disclosed in the above-described embodiment. For example, some components may be deleted from all the components shown in the embodiment.

[Supplementary note]
The present application discloses the following invention.

(Supplementary Note 1)
An ink mist collecting apparatus for collecting ink mist generated along with discharge of ink by an ink jet head that discharges ink onto a print medium to be conveyed to form an image, comprising:
A duct having a mist suction opening that opens opposite to the print medium and extends in the width direction of the print medium;
And a suction unit for suctioning and collecting ink mist into the duct through the mist suction opening by sucking air from the duct.
The duct has a groove for receiving an ink droplet formed by aggregation of the ink mist sucked in the duct and flowing the ink droplet to the outside of the print medium in the width direction. Recovery device.

(Supplementary Note 2)
The ink mist collecting device according to claim 1, wherein the duct has a plurality of grooves having different widths and / or depths.

(Supplementary Note 3)
The duct is
The area where the suction portion is provided with a suction port for sucking air from the duct, and the area where the mist suction opening is provided, have a partition plate for dividing the inside of the duct,
The partition plate is formed with a plurality of partition plate openings for communicating between the areas partitioned by the partition plate,
The ink mist collecting device according to claim 1 or 2, wherein the plurality of partition plate openings are formed such that the opening area becomes larger as it goes away from the suction port in the width direction.

Reference Signs List 1 printing system 2 unwinding device 3 inkjet printing device 4 take-up device 21 transport unit 22, 22A, 22B printing unit 23 printing device control unit 51 head unit 56 inkjet head 57 ink mist collecting unit 66 duct 67, 67A, 67B ink receiver Part 68 Suction path part 69 Suction part 71 Mist suction opening 72 to 74, 72A to 74A, 72B to 74B Groove 76 Partition plate 77 Lower area 78 Upper area 79 Suction port 81 Partition plate opening 86 Connection tube 87 tube

Claims (3)

An ink mist collecting apparatus for collecting ink mist generated along with discharge of ink by an ink jet head that discharges ink onto a print medium to be conveyed to form an image, comprising:
A duct having a mist suction opening that opens opposite to the print medium and extends in the width direction of the print medium;
And a suction unit for suctioning and collecting ink mist into the duct through the mist suction opening by sucking air from the duct.
The duct has a groove for receiving an ink droplet formed by aggregation of the ink mist sucked in the duct and flowing the ink droplet to the outside of the print medium in the width direction. Recovery device.   The ink mist collecting apparatus according to claim 1, wherein the duct has a plurality of grooves having different widths and / or depths. The duct is
The area where the suction portion is provided with a suction port for sucking air from the duct, and the area where the mist suction opening is provided, have a partition plate for dividing the inside of the duct,
The partition plate is formed with a plurality of partition plate openings for communicating between the areas partitioned by the partition plate,
3. The ink mist collecting device according to claim 1, wherein the plurality of partition plate openings are formed such that the opening area becomes larger as it goes away from the suction port in the width direction.