JP2019155651A - Image formation apparatus - Google Patents

Abstract

To provide an image formation apparatus in which a blowing direction of air blown from an outlet is inclined to a downstream side of a transport direction of a recording medium in view from a width direction of the recording medium, and compared with a case in which an inclination angle is larger than 60 degrees or smaller than 20 degrees, adhesion of mist to the recording medium can be suppressed.SOLUTION: The image formation apparatus is configured so that, a blowing direction of air blown from an outlet of a mist collection device is, in view from a width direction of the recording medium, inclined to a downstream side of the transport direction of the recording medium, and the inclination angle is 20 degrees or larger and 60 degrees or smaller.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming apparatus.

  The mist collection mechanism described in Patent Document 1 has a suction port that sucks air containing mist and a blower outlet that blows out air to guide the air containing mist to the suction port.

Japanese Patent Laying-Open No. 2015-083372

  The problem of the present invention is that the direction in which the air blown from the blowout port is inclined to the downstream side in the conveyance direction of the recording medium when viewed from the width direction of the recording medium, and the inclination angle is greater than 60 degrees, or Compared to the case where the angle is smaller than 20 degrees, the mist is prevented from adhering to the recording medium.

  According to a first aspect of the present invention, there is provided an image forming apparatus having a nozzle surface on which a plurality of nozzles for ejecting liquid droplets toward a recording medium are formed and arranged at intervals in the conveyance direction of the recording medium. Between the droplet discharge heads of the recording medium and the droplet discharge heads adjacent to each other in the conveyance direction of the recording medium, and an air outlet that blows air toward the recording medium, and an upstream side of the air outlet in the conveyance direction of the recording medium A suction port for sucking air blown out from the blowout outlet together with the mist of the droplets, and the blowout direction of the air blown out from the blowout opening is as viewed from the width direction of the recording medium. Between the mist collection device that is inclined downstream in the transport direction and has an inclination angle of 20 degrees or more and 60 degrees or less, and the droplet ejection head and the mist collection apparatus that are adjacent in the transport direction of the recording medium. Placed in And a suppressing member that suppresses the liquid droplet mist from entering between the liquid droplet ejection head and the mist collecting device. And

  An image forming apparatus according to a second aspect of the present invention has a nozzle surface on which a plurality of nozzles that discharge liquid droplets toward a recording medium are formed so as to face the recording medium to be conveyed, and the conveyance direction of the recording medium A plurality of liquid droplet ejection heads arranged at intervals, a liquid ejection port disposed between the liquid droplet ejection heads adjacent in the recording medium conveyance direction, and for blowing air toward the recording medium; A suction port for sucking air blown from the blower outlet together with the mist of the droplets on the upstream side of the blower outlet in the transport direction; and a blowout passage through which the air blown from the blower outlet flows. The path is inclined downstream of the recording medium conveyance direction when viewed from the width direction of the recording medium, and the mist collecting device has an inclination angle of 20 degrees or more and 60 degrees or less, and in the conveyance direction of the recording medium. Adjacent droplet ejection An opposing surface that is disposed between the head and the mist collecting device and faces the recording medium to be conveyed is formed, and the droplet mist enters between the droplet discharge head and the mist collecting device. And a suppressing member that suppresses the above.

An image forming apparatus according to a third aspect of the present invention is the image forming apparatus according to the first or second aspect, wherein the mist collecting device is opposed to the recording medium, and the air outlet and the air inlet are formed. If there is another facing surface, the distance from the other facing surface to the recording medium is L1, and the distance from the outlet to the suction port in the recording medium transport direction is L2, the following formula (1) It is characterized by that.
L2 ≦ L1 × 10 (1)

  The image forming apparatus according to a fourth aspect of the present invention is the image forming apparatus according to the third aspect, wherein the mist collecting device is configured to flow upstream of the recording medium in the conveyance direction while air sucked from the suction port flows. A suction passage formed including an upstream wall surface facing, wherein, in the other facing surface, a portion between the suction port and the outlet is defined as a first facing surface, and the first facing surface and the upstream wall surface A chamfered portion is formed on the ridgeline formed by.

  The image forming apparatus according to a fifth aspect of the present invention is the image forming apparatus according to any one of the first to fourth aspects, wherein the mist collecting device is opposed to the recording medium, and the air outlet and the suction port. And a suction path through which air sucked from the suction port flows. The suction path is viewed from the width direction of the recording medium, and the other facing surface is a recording medium. It is characterized by extending in a facing direction opposite to or inclined toward the downstream side in the conveyance direction of the recording medium.

  An image forming apparatus according to a sixth aspect of the present invention is the image forming apparatus according to the fifth aspect, wherein the mist collecting device has a blow-out path through which air blown from the blow-out port flows, and the suction path is The recording medium is characterized by extending along the blowing path as viewed from the width direction of the recording medium.

  An image forming apparatus according to a seventh aspect of the present invention is the image forming apparatus according to any one of the first to sixth aspects, wherein the mist collecting device faces the recording medium, and the air outlet and the suction port. The other facing surface has a portion between the suction port and the air outlet as a first facing surface, and in the recording medium transport direction, the suction port On the other hand, when the upstream portion is the second facing surface, the distance from the second facing surface to the recording medium is longer than the distance from the first facing surface to the recording medium. Features.

  An image forming apparatus according to an eighth aspect of the present invention is the image forming apparatus according to the seventh aspect, wherein the mist collecting device is configured such that the air sucked from the suction port flows and the downstream side in the conveyance direction of the recording medium. It has a suction passage formed including a downstream wall surface facing, and a chamfered portion is formed on a ridge line between the second facing surface and the downstream wall surface.

  An image forming apparatus according to a ninth aspect of the present invention is the image forming apparatus according to any one of the first to eighth aspects, wherein the mist collecting device faces the recording medium, and the air outlet and the suction port. It has another facing surface in which a mouth is formed, and the air blown out from the air outlet flows between the other facing surface and the recording medium and is sucked from the suction port to capture mist contained in the air. The air is blown out again from the air outlet.

  According to the image forming apparatus of the first aspect of the present invention, the blowing direction of the air blown from the blower outlet is inclined to the downstream side in the recording medium conveyance direction when viewed from the width direction of the recording medium, and the inclination angle is 60. It is possible to suppress the mist from adhering to the transported recording medium as compared with the case where it is larger than [degree] or smaller than 20 [degree].

  According to the image forming apparatus of claim 2 of the present invention, when the blowing path is inclined downstream in the recording medium conveyance direction when viewed from the width direction of the recording medium, and the inclination angle is larger than 60 degrees, or Compared with the case of less than 20 degrees, it is possible to suppress the mist from adhering to the recording medium to be conveyed.

  According to the image forming apparatus of the third aspect of the present invention, compared to the case where the distance L2 from the blowout port to the suction port is larger than 10 times the distance L1 from the other facing surface to the recording medium, the conveyed recording is performed. It is possible to suppress mist from adhering to the medium.

  According to the image forming apparatus of the fourth aspect of the present invention, the distance from the air outlet to the air inlet is shortened as compared with the case where the corner (pin angle) is formed between the first facing surface and the upstream wall surface. can do.

  According to the image forming apparatus of claim 5 of the present invention, as compared with the case where the suction path is inclined to the upstream side in the recording medium conveyance direction when viewed from the width direction of the recording medium, It is possible to increase the amount of air that flows to the upstream side in the conveyance direction of the recording medium and is sucked from the suction port.

  According to the image forming apparatus of the sixth aspect of the present invention, the minimum thickness between the suction path and the blowout path is compared with the case where the suction path extends in the facing direction in which the other facing surface faces the recording medium. In addition, the distance from the air outlet to the air inlet can be shortened.

  According to the image forming apparatus of claim 7 of the present invention, the mist adheres to the recording medium as compared with the case where the distance from the second facing surface to the recording medium is the same as the distance from the first facing surface to the recording medium. Can be suppressed.

  According to the image forming apparatus of claim 8 of the present invention, it is possible to suppress the mist from adhering to the recording medium as compared with the case where the corner (pin angle) is formed between the second facing surface and the downstream wall surface. can do.

  According to the image forming apparatus of the ninth aspect of the present invention, the number of parts can be reduced as compared with the case of using a discharge mechanism that discharges the air sucked from the suction port to the outside of the apparatus.

FIG. 3 is an enlarged cross-sectional view illustrating a blow-out path and a suction path of the mist collection device of the image forming apparatus according to the first embodiment of the present invention. FIG. 3 is an enlarged cross-sectional view illustrating a blow-out path and a suction path of the mist collection device of the image forming apparatus according to the first embodiment of the present invention. 1 is a cross-sectional view illustrating a mist collection device of an image forming apparatus according to a first embodiment of the present invention. (A) (B) (C) It is drawing which showed the evaluation result at the time of evaluating the mist collection | recovery apparatus of the image forming apparatus which concerns on 1st Embodiment of this invention with the graph. 4 is a graph showing an evaluation result when evaluating the mist collecting apparatus of the image forming apparatus according to the first embodiment of the present invention. 5 is a table showing evaluation results when evaluating the mist collecting apparatus of the image forming apparatus according to the first embodiment of the present invention. 1 is a perspective view illustrating a support member of an image forming apparatus according to a first embodiment of the present invention. 1 is a front view showing a droplet discharge head and a mist collection device of an image forming apparatus according to a first embodiment of the present invention. 1 is a schematic configuration diagram illustrating an image forming apparatus according to a first embodiment of the present invention. FIG. 5 is a cross-sectional view illustrating a modification of the image forming apparatus according to the first embodiment of the present invention. 1 is a cross-sectional view showing a comparative form of an image forming apparatus according to a first embodiment of the present invention. 1 is a cross-sectional view showing a comparative form of an image forming apparatus according to a first embodiment of the present invention. FIG. 6 is an enlarged cross-sectional view illustrating a blow-out path and a suction path of a mist collecting device of an image forming apparatus according to a second embodiment of the present invention. FIG. 6 is an enlarged cross-sectional view illustrating a blow-out path and a suction path of a mist collecting device of an image forming apparatus according to a third embodiment of the present invention. FIG. 10 is an enlarged cross-sectional view illustrating a blowout path and a suction path of a mist collection device of an image forming apparatus according to a fourth embodiment of the present invention. It is sectional drawing which showed the modification of embodiment of this invention.

<First Embodiment>
An example of the image forming apparatus according to the first embodiment of the present invention will be described with reference to FIGS. In the drawing, an arrow H indicates the vertical direction of the apparatus (vertical direction), an arrow W indicates the apparatus width direction (horizontal direction), and an arrow D indicates the depth direction of the apparatus (horizontal direction).

(Overall configuration of image forming apparatus 10)
As shown in FIG. 9, the image forming apparatus 10 includes a transport mechanism 20 that transports continuous paper P as a recording medium, a droplet discharge head 30 that forms an image by an inkjet method, and a discharge from the droplet discharge head 30. And a mist collecting device 40 for collecting the mist of the liquid droplets.

[Conveyance mechanism 20]
The transport mechanism 20 rotates the take-up roll 22 for unwinding the continuous paper P, the take-up roll 24 for winding the continuous paper P, the plurality of transport rolls 26 for transporting the continuous paper P, and the take-up roll 24. And a drive unit 28. As a result, the take-up roll 24 rotates in the direction of the arrow in the drawing to take up the continuous paper P, and the unwind roll 22 takes up the continuous paper P.

  The plurality of transport rolls 26 are so-called driven rolls, and are wound around the continuous paper P between the unwinding roll 22 and the winding roll 24. Accordingly, the plurality of transport rolls 26 define a transport path 102 for the continuous paper P from the unwind roll 22 to the take-up roll 24. And the conveyance roll 26 forms the circular arc path 102A which conveys the continuous paper P in the circular arc shape which protrudes upwards seeing from the apparatus depth direction.

[Droplet discharge head 30]
Four droplet discharge heads 30 are provided for each color, and are disposed above the continuous paper P so as to face the continuous paper P conveyed in the circular arc path 102A in the vertical direction. In the present embodiment, a droplet discharge head 30Y that discharges Y (yellow) droplets, a droplet discharge head 30M that discharges M (magenta) droplets, and a droplet discharge that discharges C (cyan) droplets The head 30C includes a droplet discharge head 30K that discharges K (black) droplets. The droplet discharge head 30K, the droplet discharge head 30C, the droplet discharge head 30M, and the droplet discharge head 30Y are arranged in this order at intervals from the upstream side to the downstream side in the transport direction of the continuous paper P. It is out. In the following description, the symbols may be omitted if the colors are not particularly distinguished.

  The droplet discharge head 30 has a rectangular parallelepiped shape extending in the apparatus depth direction. As shown in FIG. 8, the droplet discharge head 30 has a nozzle surface 32 on which a plurality of nozzles (not shown) are formed. The nozzle surface 32 faces the continuous paper P to be conveyed.

[Mist collection device 40]
As shown in FIG. 9, four mist collecting devices 40 are provided and face the continuous paper P in the vertical direction on the downstream side in the transport direction of the continuous paper P with respect to the droplet discharge heads 30 of each color. Are arranged to be. Details of the mist collection device 40 will be described later.

(Main part configuration)
Next, the mist collection device 40 and the support member 80 that supports the mist collection device 40 and the droplet discharge head 30 will be described. In the following description, the mist collecting device 40 facing the continuous paper P in a portion where the transport path is along the device width direction as viewed from the device depth direction will be described as an example.

[Mist collection device 40]
The mist collecting device 40 has a rectangular parallelepiped shape extending in the depth direction of the device. As shown in FIGS. 8 and 9, the mist collecting device 40 is downstream of the color droplet discharge head 30 in the transport direction of the continuous paper P. These are arranged so as to face the continuous paper P, respectively. That is, the three mist collecting devices 40 on the upstream side in the transport direction of the continuous paper P are arranged between the droplet discharge heads 30 adjacent in the transport direction of the continuous paper P. As shown in FIG. 3, the mist collecting device 40 includes a housing 44, a fan 46 and a filter 48 disposed inside the housing 44.

−Case 44−
The housing 44 includes a box-shaped main body 50 that is open at the bottom, and a closing portion 52 that closes the opening of the main body 50. The closing portion 52 is formed in a plate shape in which a plate surface (an opposing surface 52A described later) faces in a facing direction in which the mist collecting device 40 faces the continuous paper P (hereinafter simply referred to as “device facing direction”). Is thicker than the thickness of the wall plate 50 </ b> A forming the main body 50.

  Further, the closing portion 52 is formed with a facing surface 52A that faces the conveyed continuous paper P. The facing surface 52A is an example of another facing surface. Further, on the upstream surface of the facing surface 52A in the transport direction of the continuous paper P, there are an air outlet 56 for blowing air toward the recording medium, and an air outlet upstream of the air outlet 56 in the transport direction of the continuous paper P. A suction port 60 for sucking air blown from the outlet 56 is formed.

  Further, the closing part 52 is formed with an outlet 56 at the lower end, and an outlet path 58 through which the air blown out from the outlet 56 flows while passing through the closing part 52 is formed. In other words, the lower end of the air outlet 58 is the air outlet 56. Further, the closing portion 52 is formed with a suction port 60 at the lower end, and a suction path 62 is formed through the closing portion 52 and through which air sucked from the suction port 60 flows. In other words, the lower end of the suction passage 62 is the suction port 60.

Next, the air outlet 56 and the air outlet 58 will be described.
As shown in FIGS. 2 and 3, the blow-out path 58 is inclined to the downstream side in the transport direction of the continuous paper P when viewed from the apparatus depth direction (the width direction of the continuous paper P). Specifically, the lower end of the blowing path 58 is disposed on the downstream side in the transport direction of the continuous paper P as compared with the upper end of the blowing path 58.

  When viewed from the depth direction of the apparatus (the width direction of the continuous paper P), the inclination angle (θ1 in FIG. 2) of the blowout path 58 is 20 degrees or more with respect to the apparatus facing direction (vertical direction in FIG. 2). 60 degrees or less.

  Furthermore, in this embodiment, the blowing width (B1 in the figure) of the blowing path 58 is 1 [mm]. The blow-out path 58 is formed to extend in the apparatus depth direction. The air outlet 56 is formed at the lower end of the air outlet path 58.

  A support portion 54 that supports the fan 46 and the filter 48 from below is formed inside the housing 44. The support portion 54 is L-shaped when viewed from the depth direction of the device, and includes a vertical portion 54A extending in the vertical direction of the device and a horizontal portion 54B extending in the device width direction from the upper end of the vertical portion 54A. Yes. Specifically, the lower end of the vertical portion 54A is attached to a portion between the upper end of the outlet passage 58 and the upper end of the suction passage 62 on the opposite surface 52B of the closing portion 52 formed on the opposite side of the facing surface 52A. ing. Furthermore, the horizontal portion 54B extends from the upper end of the vertical portion 54A to one side (right side in the drawing) in the apparatus width direction. The one end of the horizontal portion 54B in the apparatus width direction is separated from the wall plate 50A of the housing 44.

  In this configuration, the blowing direction of the air blown out from the blower outlet 56 is the same as the inclination direction of the blowout path 58 and is inclined downstream in the conveying direction of the continuous paper P when viewed from the apparatus depth direction. Specifically, the air blowing direction is set to 20 degrees or more and 60 degrees or less with respect to the apparatus facing direction. In other words, the air blown out from the blowout port 56 is directed to the downstream portion of the continuous paper P in the transport direction of the continuous paper P with respect to the portion facing the blowout port 56 in the continuous paper P.

Next, the suction port 60 and the suction path 62 will be described.
2 and 3, the suction path 62 is disposed on the upstream side of the blowout path 58 in the transport direction of the continuous paper P, and extends in the apparatus facing direction when viewed from the apparatus depth direction. . Furthermore, in this embodiment, the suction width (B2 in the drawing) of the suction passage 62 is 3 [mm]. The suction passage 62 is formed extending in the apparatus depth direction. The suction port 60 is formed at the lower end of the suction path 62.

  A sponge member 64 that is a porous body that absorbs liquid is formed on the wall surface of the suction passage 62. In addition, about the member which forms the wall surface of the suction path 62, what is necessary is just a member which captures mist, for example, a nonwoven fabric etc. may be sufficient.

Further, if the distance from the facing surface 52A to the continuous paper P is L1, and the distance from the air outlet 56 to the suction port 60 in the transport direction of the continuous paper P (left and right in FIG. 2) is L2, the following formula (1) Is true. It should be noted that the distance from the facing surface 52A to the continuous paper P shown in each drawing is widened to show the air flow between the facing surface 52A and the continuous paper P.
L2 ≦ L1 × 10 (1)

  Here, the distance from the air outlet 56 to the suction port 60 is the shortest distance from the edge of the air outlet 56 to the edge of the air inlet 60. The distance L2 is preferably 6 times or less of L1 and more preferably 3 times or less of L1 in consideration of the mist recovery performance described later.

  Moreover, in order to stabilize the blowing direction of the air blown from the blower outlet 56, it is necessary to lengthen the blowout path 58. For this reason, the minimum value of the distance L2 is preferably 2 [mm] or more, and more preferably 4 [mm] or more. In the present embodiment, the distance L1 is 1 [mm], and the distance L2 is 10 [mm].

−Fan 46, filter 48−
As shown in FIG. 3, the fan 46 and the filter 48 are arranged side by side in the apparatus width direction inside the housing 44. Specifically, the fan 46 and the filter 48 are arranged in this order from one side (right side in the figure) to the other side (left side in the figure) in the apparatus width direction, and from below to the horizontal part 54B of the support part 54. It is supported. The wall plate 50A on one side of the casing 44 in the apparatus width direction and the fan 46 are separated in the apparatus width direction, and the wall board 50A on the other side of the casing 44 in the apparatus width direction and the filter 48 are separated from each other. They are separated in the width direction.

  The fans 46 are axial fans, and are provided in a plurality in the apparatus depth direction so that air flows from the other side (left side in the figure) to one side (right side in the figure) in the apparatus width direction. Yes.

  The filter 48 is a plate-like member for capturing mist that flows with air, and the plate surface faces the apparatus width direction. The filter 48 is a member that captures the mist M and allows air to pass therethrough. The filter 48 extends in the apparatus depth direction.

[Support member 80]
As shown in FIGS. 3 and 9, the support member 80 is disposed above the circular arc path 102 </ b> A through which the continuous paper P is conveyed in an arc shape. The support member 80, the mist collecting device 40, and the discharge head 30 form a space between the circular arc path 102A. In the embodiment, the support member 80 has an arc shape along the circular arc path 102 when viewed from the apparatus width direction, and the support member 80 is provided with a facing surface 80A that faces the continuous paper P. The support member 80 is an example of a suppression member.

  Further, as shown in FIG. 7, the support member 80 has rectangular through holes 80 </ b> B extending in the apparatus depth direction as viewed from above, spaced from the upstream side to the downstream side in the transport direction of the continuous paper P. A plurality are formed in the space. The lower end portion of the droplet discharge head 30 and the lower end portion of the mist collecting device 40 are inserted into the through hole 80B. Then, the droplet discharge head 30 and the mist are disposed in a state in which the facing surface 80A of the support member 80, the nozzle surface 32 of the droplet discharge head 30, and the facing surface 52A of the mist collecting device 40 are arranged on the same curved surface. The collection device 40 is attached to the support member 80 using an attachment member (not shown) (see FIG. 8). For example, the support member 80 does not have a function of supporting the droplet discharge head 30, and the mist M of the droplets discharged from the droplet discharge head 30 is converted into the droplet discharge head 30 and the mist collection device 40. What is necessary is just to have a function which suppresses entering between. In this case, another member that supports the droplet discharge head 30 is required. The support member 80 is not integrated, and may be divided so as to function as a suppressing member in combination so as to face the circular arc path 102A.

(Function)
Next, the operation of the mist collecting device 40 will be mainly described.

  When the image forming apparatus 10 is operated and the image forming apparatus 10 receives an image forming instruction, the continuous paper P is transported and droplets (ink droplets) are directed toward the continuous paper P to which the droplet discharge heads 30 of the respective colors are transported. Is discharged. From the droplet discharge head 30, mist (mist-like liquid) is also discharged together with the droplet. The mist M flows along the continuous paper P to be conveyed while floating in the air from the upstream side to the downstream side in the conveyance direction of the continuous paper P.

  On the other hand, in the mist collecting apparatus 40 shown in FIG. 3, when the fan 46 is operated, the fan 46 causes air to flow from the other side (left side in the figure) to one side (right side in the figure) in the apparatus width direction. In other words, the fan 46 sucks air on the other side in the apparatus width direction with respect to the fan 46, and discharges air to one side in the apparatus width direction with respect to the fan 46. The air discharged from the fan 46 hits the wall plate 50A and flows downward (see arrow G1 in FIG. 3). Further, the air that has flowed downward hits the opposite surface 52B of the closing portion 52 and flows to the other side in the apparatus width direction (see arrow G2 in FIG. 3). Furthermore, the air that has flowed to the other side in the apparatus width direction hits the vertical portion 54A of the support portion 54 and flows to the blowout path 58 (see arrow G3 in FIG. 3).

  Further, the fan 46 sucks air on the other side in the apparatus width direction with respect to the fan 46, so that the air between the continuous paper P and the suction port 60 is sucked from the suction port 60, and the sucked air is , Flows through the suction path 62 and flows upward from the suction path 62 (arrow G4 in FIG. 3). Furthermore, the air that has flowed upward flows through the filter 48 toward the fan 46 (see arrow G5 in FIG. 3).

  Here, as shown in FIG. 1, the air that has flowed to the blowout path 58 blows out toward the continuous paper P conveyed from the blowout port 56. Further, as described above, the air between the continuous paper P and the suction port 60 is sucked from the suction port 60 (arrow G4 in FIG. 1). For this reason, the air blown out toward the continuous paper P conveyed from the blower outlet 56 turns back to the upstream side in the conveyance direction of the continuous paper P and is sucked from the suction port 60 (arrow G6 in FIG. 1). Thereby, between the suction inlet 60 and the continuous paper P, the airflow which flows from the surface of the continuous paper P to the suction inlet 60 arises (part | part J1 in a figure).

  Therefore, the mist M that flows while floating in the air along the transported continuous paper P to the downstream side in the transport direction of the continuous paper P is blocked by this air flow and passes through the suction port 60 to the suction path 62. Flows in. Furthermore, the mist M that has flowed into the suction passage 62 is collected by being captured by the filter 48.

  Next, a description will be given of a result of evaluating the mist recovery rate of the mist M flowing along the continuous paper P downstream in the conveyance direction of the continuous paper P using analysis. The mist recovery rate is the ratio of mist M that can be recovered to the generated mist M.

[Factor evaluation]
First, it was evaluated using analysis how the mist recovery rate greatly changed. It should be noted that the scale is the same for the vertical axis of each diagram of FIG. 4 described below.

  FIG. 4A shows a graph in which the vertical axis represents the mist recovery rate and the horizontal axis represents the suction width B2 (see FIG. 2) of the suction passage 62. From this graph, it can be seen that the change in the mist recovery rate due to the suction width B2 is small.

  FIG. 4B shows a graph in which the vertical axis represents the mist recovery rate and the horizontal axis represents the inclination angle θ1 (see FIG. 2) of the outlet path 58. From this graph, it can be seen that the change in the mist recovery rate due to the inclination angle θ1 is large.

  FIG. 4C shows a graph in which the vertical axis is the mist recovery rate and the horizontal axis is the distance L2 (see FIG. 2) from the air outlet 56 to the suction port 60. From this graph, it can be seen that the change in the mist recovery rate due to the size of the distance L2 is large.

  From the above factor evaluation results, it can be seen that the mist recovery rate is greatly changed by changing the inclination angle θ1 of the air outlet 58 or the distance L2 from the air outlet 56 to the air inlet 60.

−Inclination angle θ1−
Next, the inclination angle θ1 of the outlet channel 58 was set finely, and the relationship between the inclination angle θ1 and the mist recovery rate was evaluated using analysis.

  FIG. 5 shows a graph in which the ordinate represents the mist recovery rate and the abscissa represents the inclination angle θ1 (see FIG. 2) of the outlet channel 58. From this graph, it can be seen that the change in the mist recovery rate due to the inclination angle θ1 is large.

  In the analysis, the conveying speed of the continuous paper P is set to 100 [m / min], the blowing speed of the air blown from the blower outlet is set to 3 [m / s], and the suction speed of the air sucked from the suction port is set. 1 [m / s]. Furthermore, the distance L1 from the facing surface 52A to the continuous paper P was 1 [mm], and the distance L2 from the air outlet 56 to the suction port 60 was 20 [mm].

  As can be seen from the graph shown in FIG. 5, the tilt angle is 20 [deg.] Or more and 60 [deg.] Or less, and the mist recovery rate is 82 [%] or more. From experience, when the mist recovery rate calculated by analysis is 82%, the deterioration in the quality of the output image due to the mist M adhering to the continuous paper P on which the halftone image is formed is acceptable in terms of merchantability. Although it is a level, the inclination angle is preferably 30 [deg.] Or more and 45 [deg.] Or less.

-Discussion-
Next, the results described above will be considered. By setting the tilt angle to 20 [degrees] or more and 60 [degrees] or less, as shown in FIG. Fold back upstream in the transport direction near the surface. Specifically, the air blown out from the air outlet 56 once goes downstream in the transport direction of the continuous paper P, and then folds up near the surface of the continuous paper P to the upstream side in the transport direction. Then, the folded air flows down to the lower side of the suction port 60 and moves upward (arrow G6 in FIG. 1).

  For this reason, an air flow flowing from the vicinity of the surface of the continuous paper P to the suction port 60 is generated below the suction port 60 (part J1). It is considered that the mist M flowing from the upstream side in the conveyance direction of the continuous paper P hits the air flow, is blocked, and is sucked into the suction path 62 from the suction port 60.

  On the other hand, in the first comparative form in which the tilt angle is larger than 60 [degrees], the tilt angle is large, so that it is blown out toward the continuous paper P conveyed from the blower outlet as shown in FIG. In the heated air, the ratio of flowing downstream in the conveyance direction of the continuous paper P increases (arrow G10 in FIG. 11). For this reason, the amount of air (arrow G11 in FIG. 11) blown out toward the continuous paper P conveyed from the blowout outlet and turned back upstream in the conveyance direction is reduced. For this reason, when the air flow (part J2) flowing from the vicinity of the surface of the continuous paper P to the suction port becomes weak, the damming effect becomes weak, and the amount of mist M sucked into the suction path 62 from the suction port 60 decreases. Think.

  Further, in the second comparative form in which the inclination angle is smaller than 20 [degrees], since the inclination angle is small, as shown in FIG. 12, the air blown out toward the continuous paper P conveyed from the outlet is Then, before reaching the vicinity of the surface of the continuous paper P, it is folded back upstream in the transport direction (arrow G20 in FIG. 11). And the turned-back air flows to the lower part of the suction inlet 60, and heads upward here. For this reason, an air flow that flows from the position away from the surface of the continuous paper P to the suction port 60 is generated below the suction port 60 (part J3). Accordingly, it is considered that the amount of the mist M blocked by the air flow is reduced, and the amount of the mist M sucked into the suction passage 62 from the suction port 60 is reduced.

-Distance L2 from air outlet to air inlet
Next, the distance L2 from the blower outlet 56 to the suction inlet 60 was set finely, and the relationship between the distance L2 and the mist recovery rate was evaluated using analysis.

  In FIG. 6, when the inclination angle θ1 of the air outlet 58 is 20 degrees and 60 degrees, and the distance L2 from the air outlet 56 to the suction port 60 is 4 mm to 20 mm. The mist recovery rate is shown in the table.

  The case where the mist recovery rate was 82% or higher was “C”, the case where the mist recovery rate was 84% or higher was “B”, and the case where the mist recovery rate was 86% or higher was “A”. As can be seen from the table shown in FIG. 6, when the distance L2 is 4 [mm] or more and 6 [mm] or less, the evaluation is “A”, and the distance L2 is 8 [mm] or more and 10 [mm] or less. In addition, the evaluation was “B”, and the evaluation was “C” when the distance L2 was 12 [mm] or more and 20 [mm] or less.

  From experience, when the mist recovery rate calculated by analysis is 84 [%], the mist M adhering to the continuous paper P can be found, but it is not a level to be worried about. When the mist collection rate calculated by analysis is 86 [%], it is difficult to find the mist M adhering to the continuous paper P.

  In the analysis, the conveying speed of the continuous paper P is set to 100 [m / min], the blowing speed of the air blown from the blower outlet is set to 3 [m / s], and the suction speed of the air sucked from the suction port is set. The distance L1 from the facing surface 52A to the continuous paper P was 1 [mm].

-Discussion-
Next, the results described above will be considered. When the distance L2 from the blower outlet 56 to the suction port 60 is long, it is considered that the amount of air blown from the blower outlet 56 and sucked from the suction port 60 is smaller than when the distance L2 is short. This is because when the distance L2 is long, the frictional force generated between the air per unit flow rate flowing from the blower outlet 56 to the suction port 60 and the facing surface 52A is larger than when the distance L2 is short. is there. For this reason, when the distance L2 from the blower outlet 56 to the suction inlet 60 is long, compared with the case where the distance L2 is short, the quantity of the air which flows from the blower outlet 56 to the suction inlet 60 decreases, and a mist collection | recovery rate is low. Become.

  As can be seen from the table shown in FIG. 6, when the mist recovery rate is taken into consideration, when the distance L1 from the facing surface 52A to the continuous paper P is 1 [mm], the distance L2 is 10 [mm] or less. Preferably, it is 6 [mm] or less.

  Here, as described above, the difference in the mist recovery rate is that when the distance L2 is long, the air per unit flow rate flowing from the blower outlet 56 to the suction port 60 is larger than when the distance L2 is short. This is because the frictional force generated between the opposing surface 52A increases. For this reason, when the distance L1 from the facing surface 52A to the continuous paper P is increased, the frictional force generated between the air per unit flow rate flowing from the blower outlet 56 to the suction port 60 and the facing surface 52A is reduced. In this analysis, when the distance L1 is 1 [mm], the distance L2 is preferably 10 [mm] or less, and more preferably 6 [mm] or less. That is, the distance L2 is preferably 10 times or less of the distance L1 from the facing surface 52A to the continuous paper P, and more preferably 6 times or less of the distance L1.

(Summary)
As described above, the inclination angle θ1 of the outlet channel 58 is not less than 20 degrees and not more than 60 degrees. For this reason, when the inclination angle θ1 is larger than 60 [degrees] or smaller than 20 [degrees], the mist recovery rate is increased, and thus the mist M is prevented from adhering to the continuous paper P. Is done.

  Further, the distance L2 from the air outlet 56 to the suction port 60 is not more than 10 times the distance L1 from the facing surface 52A to the continuous paper P. For this reason, compared to the case where the distance L2 is larger than 10 times the distance L1, the mist recovery rate is increased, and thus the mist M is prevented from adhering to the continuous paper P.

  Further, the suction passage 62 extends in the device facing direction when viewed from the device depth direction. For this reason, for example, as shown in FIG. 10, as compared with the case where the suction path is inclined to the upstream side in the transport direction of the continuous paper P, the air is blown out from the blowout port 56 and The amount of air that flows upstream and is sucked from the suction port 60 increases. Accordingly, the mist M is prevented from adhering to the continuous paper P as compared with the case where the suction path is inclined upstream in the transport direction of the continuous paper P.

  The air blown out from the blowout port 56 flows between the facing surface 52 </ b> A and the continuous paper P, is sucked in from the suction port 60, and blows out from the blowout port 56 again through the filter 48 and the fan 46. For this reason, the number of parts is reduced as compared with the case of using a discharge mechanism that discharges air to the outside of the image forming apparatus 10.

  Among the mists M that have not been collected by the mist collecting device, there are those that do not adhere to the continuous paper P and flow while floating to the vicinity of the discharge head 30 on the downstream side. Some may adhere to the surface of the ejection head due to the influence. In this case, the dirt on the surface of the ejection head is accelerated, so that not only the maintenance cost such as cleaning increases, but also the accuracy of droplet ejection from the ejection head 30 decreases due to the attached mist M or the droplet ejection. In some cases, the print quality may be deteriorated due to obstruction. Improvement of the mist recovery rate also has an effect of preventing these troubles.

  Further, in the mist collecting apparatus of the present invention, most of the air blown out from the blowout port 56 proceeds upstream and is sucked from the suction port 60, so that it is directed toward the discharge head 30 downstream from the blowout port 56. It hardly goes. When the air flowing out from the air outlet 56 toward the downstream side increases, the flying accuracy and landing position accuracy of the liquid droplets ejected from the ejection head 30 are lowered due to the excess wind speed, and the print quality is degraded. There is. The mist collecting apparatus of the present invention also has an effect of preventing these troubles.

Second Embodiment
An example of the image forming apparatus according to the second embodiment of the present invention will be described with reference to FIG. The image forming apparatus according to the second embodiment will be described mainly with respect to differences from the image forming apparatus according to the first embodiment.

  In the mist collecting device 140 provided in the image forming apparatus 110 of the second embodiment, as shown in FIG. 13, the portion between the suction port 60 and the outlet 56 on the facing surface 52 </ b> A of the mist collecting device 140 is The first facing surface 154 is used. Further, in the wall surface forming the suction path 62, the wall surface facing the upstream side in the transport direction of the continuous paper P is an upstream wall surface 62A. A flat chamfered portion 158 (so-called C chamfering) is formed on the ridgeline between the first facing surface 154 and the upstream wall surface 62A.

  For this reason, compared with the case where the 1st opposing surface 154, the upstream wall surface 62A, and the corner | angular part (pin angle) are formed, the distance L2 from the blower outlet 56 to the suction inlet 60 becomes short, and mist collection | recovery rate is obtained. It becomes high and it is suppressed that the mist M adheres to the continuous paper P.

  In addition, about another effect | action of 2nd Embodiment, it is the same as that of 1st Embodiment.

<Third Embodiment>
An example of an image forming apparatus according to the third embodiment of the present invention will be described with reference to FIG. Note that the image forming apparatus according to the third embodiment will be described mainly with respect to differences from the image forming apparatus according to the first embodiment.

  In the mist collecting device 240 provided in the image forming apparatus 210 of the third embodiment, the suction path 262 extends along the blowout path 58 as seen from the depth direction of the apparatus, as shown in FIG.

  For this reason, compared with the case where the suction path extends in the device facing direction, the distance L2 from the outlet 56 to the inlet 260 is maintained while maintaining the minimum thickness between the suction path 262 and the outlet path 58. Shorter. Furthermore, since the distance L2 is shortened, the mist recovery rate is increased and the mist M is prevented from adhering to the continuous paper P as compared with the case where the suction path extends in the apparatus facing direction.

<Fourth embodiment>
An example of an image forming apparatus according to the fourth embodiment of the present invention will be described with reference to FIG. The image forming apparatus according to the fourth embodiment will be described mainly with respect to differences from the image forming apparatus according to the first embodiment.

  In the mist collection device 340 provided in the image forming apparatus 310 of the fourth embodiment, as shown in FIG. 15, the portion between the suction port 60 and the air outlet 56 on the facing surface 52A of the mist collection device 340 is The first facing surface 354 is used. Further, the upstream portion of the facing surface 52 </ b> A in the transport direction of the continuous paper P with respect to the suction port 60 is a second facing surface 358. The distance from the second facing surface 358 to the continuous paper P (L10 in FIG. 15) is longer than the distance from the first facing surface 354 to the continuous paper P (L11 in FIG. 15). In the present embodiment, the distance L11 is the same distance as the distance L1 in the first embodiment.

  A wall surface that forms the suction path 62 and faces the downstream side in the transport direction of the continuous paper P is a downstream wall surface 62B. A flat chamfered portion 362 (so-called C chamfering) is formed on the ridgeline between the second facing surface 358 and the downstream wall surface 62B.

  In this configuration, the portion of the mist M that flows while floating in the air from the upstream side to the downstream side in the conveyance direction of the continuous paper P is blocked by the wall surface that forms the suction path 62 (see FIG. Middle site J4). The blocked mist M flows to the suction passage 62 through the suction port 60.

  For this reason, compared with the case where the distance from the second facing surface to the continuous paper P is the same as the distance from the first facing surface to the continuous paper P, the mist recovery rate becomes higher, so that the mist M is formed on the continuous paper P. Adhesion is suppressed.

  Further, a chamfered portion 362 is formed on the ridge line between the second facing surface 358 and the downstream wall surface 62B. For this reason, compared with the case where the corner | angular part (pin angle | corner) is formed with the 2nd opposing surface and the downstream wall surface, the quantity of the mist M blocked by the wall surface which forms the suction path 62 increases. As a result, the mist recovery rate is increased and the mist M is prevented from adhering to the continuous paper P.

  Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to such embodiments, and various other embodiments can be taken within the scope of the present invention. This will be apparent to those skilled in the art. For example, in the above embodiment, the air blowing direction of the air blown from the air outlet 56 is changed by changing the inclination angle of the air outlet 58, but the air blowing direction is changed by arranging fins or the like at the air outlet. You may change it.

  Moreover, in the said embodiment, although the distance L2 from the blower outlet 56 to the suction inlet 60 was made into 10 times or less of the distance L1 from 52 A of opposing surfaces to the continuous paper P, the distance L2 is larger than 10 times of the distance L1. May be. However, in this case, the equivalent effect achieved by setting the distance L2 to 10 times or less of the distance L1 is not achieved.

  Moreover, although the chamfering part formed in the ridgeline in the said 2nd Embodiment and 4th Embodiment was C chamfering, R chamfering may be sufficient, for example.

  In the above-described embodiment, each embodiment has been described using the image forming apparatuses 10, 110, 210, and 310 that form an image on the continuous paper P. However, the image forming apparatus forms an image on a sheet of paper. Also good.

  In the above embodiment, the support member 80 and the droplet discharge head 30 are separate, but the member on which the opposing surface 80A of the support member 80 is formed and the nozzle surface 32 of the droplet discharge head 30 are formed. The formed member may be integrally formed.

  Further, in the above embodiment, the support member 80 and the mist collection devices 40, 140, 240, and 340 are separate bodies, but the member on which the facing surface 80A of the support member 80 is formed and the mist collection devices 40, 140, 240 and 340 may be formed integrally with the member on which the facing surface 52A is formed.

  Further, although not particularly described in the above embodiment, the blowing speed of the air blown from the blower outlet 56 may be changed according to the conveyance speed of the continuous paper P.

  Although not particularly described in the above embodiment, when the width of the blowout path is different between the lower end and the upper end, as shown in FIG. 16, a line connecting the center of the lower end and the center of the upper end is used. Measure the inclination angle of the outlet.

  In the above-described embodiment, the mist collecting device 40 is also arranged on the downstream side of the droplet discharge head 30Y in the transport direction of the continuous paper P. However, the mist collecting device 40 is a liquid adjacent to the continuous paper P in the transport direction. What is necessary is just to arrange | position between the droplet discharge heads 30.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 30 Droplet discharge head 32 Nozzle surface 40 Mist collection | recovery apparatus 52A Opposing surface (an example of another opposing surface)
56 Outlet 58 Outlet path 60 Suction port 62 Suction path 62A Upstream wall surface 62B Downstream wall surface 80 Support member (an example of a restraining member)
80A Opposing surface 110 Image forming device 140 Mist collecting device 154 First facing surface 158 Chamfer 210 Image forming device 240 Mist collecting device 260 Suction port 262 Suction passage 310 Image forming device 340 Mist collecting device 354 First facing surface 358 Second facing Surface 362 Chamfer

Claims (9)

A plurality of liquid droplet ejection heads having a nozzle surface on which a plurality of nozzles for ejecting liquid droplets toward the recording medium are formed and arranged at intervals in the conveyance direction of the recording medium;
An air outlet that is disposed between the droplet discharge heads adjacent in the recording medium conveyance direction and blows air toward the recording medium, and is blown out from the air outlet on the upstream side of the air outlet in the recording medium conveyance direction. A suction port for sucking the air to be discharged together with the mist of the droplets, and the blowing direction of the air blown from the blower outlet is inclined to the downstream side in the recording medium conveyance direction when viewed from the width direction of the recording medium. A mist collection device having an inclination angle of 20 [deg.] Or more and 60 [deg.] Or less,
An opposing surface is formed between the droplet discharge heads adjacent to each other in the recording medium conveyance direction and the mist collecting device, and is opposed to the recording medium to be conveyed. A restraining member that suppresses entry between the head and the mist collecting device;
An image forming apparatus comprising: A plurality of droplet discharges having a nozzle surface on which a plurality of nozzles that discharge droplets toward the recording medium are formed facing the recording medium to be conveyed and arranged at intervals in the conveyance direction of the recording medium Head,
An air outlet that is disposed between the droplet discharge heads adjacent in the recording medium conveyance direction and blows air toward the recording medium, and is blown out from the air outlet on the upstream side of the air outlet in the recording medium conveyance direction. A suction port for sucking air to be discharged together with the mist of the droplets, and a blow-out path through which the air blown from the blow-out port flows, and the blow-out path conveys the recording medium when viewed from the width direction of the recording medium. A mist collecting device that is inclined downstream in the direction and has an inclination angle of 20 degrees or more and 60 degrees or less;
An opposing surface is formed between the droplet discharge heads adjacent to each other in the recording medium conveyance direction and the mist collecting device, and is opposed to the recording medium to be conveyed. A restraining member that suppresses entry between the head and the mist collecting device;
An image forming apparatus comprising: The mist collecting device is opposed to the recording medium and has another facing surface in which the air outlet and the suction port are formed.
The following formula (1) is established, where L1 is a distance from the other facing surface to the recording medium, and L2 is a distance from the air outlet to the suction port in the recording medium conveyance direction. The image forming apparatus according to 2.
L2 ≦ L1 × 10 (1) The mist collection device has a suction path formed including an upstream wall surface facing the upstream side in the conveyance direction of the recording medium while air sucked from the suction port flows.
In the other facing surface, a portion between the suction port and the outlet is a first facing surface,
The image forming apparatus according to claim 3, wherein a chamfered portion is formed on a ridgeline formed by the first facing surface and the upstream wall surface. The mist collecting device is
Opposing the recording medium, the other facing surface in which the air outlet and the suction port are formed,
A suction path through which air sucked from the suction port flows, and
5. The suction path, as viewed from the width direction of the recording medium, the other facing surface extends in the facing direction facing the recording medium, or is inclined downstream in the conveyance direction of the recording medium. The image forming apparatus according to any one of the above. The mist collecting device has a blow-out path through which air blown from the blow-out port flows,
The image forming apparatus according to claim 5, wherein the suction path extends along the blowing path when viewed from the width direction of the recording medium. The mist collecting device is opposed to the recording medium and has another facing surface in which the air outlet and the suction port are formed.
In the other facing surface, a portion between the suction port and the air outlet is a first facing surface, and a portion upstream of the suction port in the recording medium transport direction is a second facing surface. ,
The image forming apparatus according to claim 1, wherein a distance from the second facing surface to the recording medium is longer than a distance from the first facing surface to the recording medium. The mist collecting device has a suction path formed by including a downstream wall surface facing the downstream side in the conveyance direction of the recording medium while air sucked from the suction port flows.
The image forming apparatus according to claim 7, wherein a chamfered portion is formed on a ridge line between the second facing surface and the downstream wall surface. The mist collecting device is opposed to the recording medium and has another facing surface in which the air outlet and the suction port are formed.
The air blown out from the air outlet flows between the other facing surface and the recording medium and is sucked in from the air inlet, captures mist contained in the air, and blows out again from the air outlet. The image forming apparatus according to any one of the above.