JP2018008534A - Ink jet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively remove paper powder.SOLUTION: An ink jet recording device 1 includes a recording head 34, a conveyance unit 31, a plate-like member 35 and a negative pressure application unit 33. The recording head 34 discharges ink onto a recording sheet P. The conveyance unit 31 conveys the recording sheet P to the image formation position by the recording head 34. The plate-like member 35 forms a narrow-gap space 35a between the placement surface (upper surface of a conveyor belt 32) of the recording sheet P in the conveyance unit 31 and itself on the upstream side in the conveyance direction of the recording sheet P with respect to the recording head 34. The negative pressure application unit 33 applies the negative pressure to the narrow-gap space 35a. In the narrow-gap space 35a, a distance in the direction orthogonal to the placement surface is set so that the velocity of the air stream flowing into the narrow-gap space 35a from the space in the periphery of the narrow-gap space 35a becomes the larger velocity after the air stream flows into the narrow-gap space 35a than the velocity before the air stream flows into the narrow-gap space 35a. The plate-like member 35 is arranged in two pieces (plate-like member 351, plate-like member 352).SELECTED DRAWING: Figure 7

Description

  The present invention relates to an ink jet recording apparatus.

  2. Description of the Related Art Conventionally, in an ink jet recording apparatus that discharges ink onto a recording medium, a technique for removing paper dust is known in order to suppress the occurrence of nozzle clogging in a recording head.

  For example, an ink jet recording apparatus is disclosed in which a paper dust collecting member is disposed upstream of the recording head in the conveyance direction of the recording medium (see Patent Document 1). The paper dust collecting member includes a vertical wall and a downstream side wall. The vertical wall rises vertically upward. The downstream side wall extends from the upper end of the vertical wall toward the downstream side in the conveyance direction of the recording medium.

  In Patent Document 1, paper dust generated as the recording medium is conveyed is collected by the paper dust collecting member before reaching the recording head, so that the amount of paper dust adhering to the recording head is reduced. It is stated that you can.

JP 2008-213255 A

  However, in the ink jet recording apparatus described in Patent Document 1, paper dust is not effectively removed because paper dust is attached to the paper dust collecting member and removed. Further, even if paper dust adheres to the paper dust collecting member, the adhered paper dust falls from the paper dust collecting member and, for example, adheres to the recording paper and is transported to the recording head. There is a risk of adhesion.

  The present invention has been made in view of the above problems, and an object thereof is to provide an ink jet recording apparatus capable of effectively removing paper dust.

  The ink jet recording apparatus of the present invention includes a plurality of recording heads, a transport unit, a space forming unit, and a negative pressure applying unit. The plurality of recording heads eject ink onto a recording medium. The conveyance unit conveys the recording medium to an image forming position by the plurality of recording heads. The space forming unit forms a narrow space between the plurality of recording heads and the mounting surface of the recording medium in the transport unit on the upstream side in the transport direction of the recording medium. The negative pressure application unit applies a negative pressure to the narrow space. The plurality of recording heads are arranged in a conveyance direction of the recording medium. In the narrow space, the velocity of the air flow flowing into the narrow space from the space around the narrow space is greater after flowing into the narrow space than before flowing into the narrow space. As described above, the distance in the direction orthogonal to the placement surface is set. A plurality of the space forming portions are arranged in the conveyance direction of the recording medium. Each of the plurality of space forming portions is arranged upstream of the recording head in the transport direction of the recording medium, more upstream of the recording head in the transport direction of the recording medium.

  According to the ink jet recording apparatus of the present invention, paper dust can be effectively removed.

It is a figure which shows the structure of the inkjet recording device which concerns on this embodiment. FIG. 2 is a diagram illustrating a configuration of an image forming unit illustrated in FIG. 1. It is a figure which shows the structure which concerns on 1st Embodiment of the plate-shaped member shown in FIG. 2, and a guide member. FIG. 4 is a cut perspective view illustrating configurations of a conveyance belt, a guide member, and a negative pressure application unit illustrated in FIG. 3. It is a top view which shows the structure of the guide member shown in FIG. It is the top view and sectional drawing which show the structure of the groove | channel and through-hole which were formed in the guide member shown in FIG. (A) is a top view which shows the structure of a groove | channel and a through-hole. (B) is AA sectional drawing which shows the structure of the groove | channel and through-hole which are shown to (a). FIG. 4 is a diagram illustrating the air flow in the narrow space when the leading edge of the sheet is located in the vicinity of the top of the through hole disposed on the downstream side in the sheet conveyance direction in the configuration according to the first embodiment illustrated in FIG. 3. . It is a figure which shows the structure which concerns on 2nd Embodiment of the plate-shaped member shown in FIG. 2, and a guide member. It is a figure which shows the structure which concerns on 3rd Embodiment of the plate-shaped member shown in FIG. 2, and a guide member. It is a figure which shows the structure which concerns on 4th Embodiment of the plate-shaped member shown in FIG. 2, and a guide member. It is a figure which shows the structure which concerns on the plate-shaped member shown in FIG. 2, and the 1st comparative form of a guide member. It is a figure which shows the structure which concerns on the plate-shaped member shown in FIG. 2, and the 2nd comparison form of a guide member.

  Embodiments of the present invention will be described below with reference to the drawings (FIGS. 1 to 12). In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof is not repeated.

  First, an ink jet recording apparatus 1 according to the present embodiment will be described with reference to FIG. FIG. 1 is a diagram illustrating a configuration of an inkjet recording apparatus 1 according to the present embodiment. The ink jet recording apparatus 1 includes an apparatus casing 100, a sheet feeding unit 2 disposed below the inside of the apparatus casing 100, an image forming unit 3 disposed above the sheet feeding unit 2, and one side of the image forming unit 3. A sheet transport unit 4 disposed on the right side in FIG. 1 and a sheet discharge unit 5 disposed on the other side (left side in FIG. 1) of the image forming unit 3 are provided.

  The paper feed unit 2 includes a paper feed cassette 21, a paper feed roller 22, and a guide plate 23. The paper feed cassette 21 stores recording paper P and is detachable from the apparatus housing 100. The paper feed roller 22 is disposed above one end (the right end in FIG. 1) of the paper feed cassette 21. The guide plate 23 is disposed between the paper feed roller 22 and the paper transport unit 4.

  A plurality of recording papers P are stored in the paper feed cassette 21. Hereinafter, “recording paper” is simply referred to as “paper” for convenience. The recording paper P corresponds to an example of “recording medium”. The paper feed roller (pickup roller) 22 is a roller that feeds the paper P along the conveyance direction of the paper P, and takes out the paper P in the paper feed cassette 21 one by one from the top. The guide plate 23 guides the paper P taken out by the paper feed roller 22 to the paper transport unit 4.

  The paper transport unit 4 includes a substantially C-shaped paper transport path 41, a first transport roller pair 42 provided on the entrance side of the paper transport path 41, a second transport roller pair 43 provided in the middle of the paper transport path 41, In addition, a registration roller pair 44 provided on the exit side of the paper conveyance path 41 is provided.

  The first transport roller pair 42 is a roller pair (feed roller pair) that feeds the paper P along the transport direction of the paper P, and sends the paper P supplied from the paper feed unit 2 to the paper transport path 41. To do. The second transport roller pair 43 is also a feed roller pair. The second transport roller pair 43 feeds the paper P sent by the first transport roller pair 42 toward the registration roller pair 44 across the paper P.

  The registration roller pair 44 performs skew correction of the paper P that has been transported by the second transport roller pair 43. In addition, the registration roller pair 44 temporarily stops the paper P in order to synchronize the timing of image formation on the paper P and the conveyance timing of the paper P, and then sets the paper P to the image formation timing. Send to forming unit 3.

  The image forming unit 3 includes a transport belt 32 and a recording head 34, and transports the paper P supplied from the registration roller pair 44 in a predetermined direction (leftward in FIG. 1) by the transport belt 32 and transports by the transport belt 32. An image is formed by the recording head 34 on the paper P being printed. The detailed configuration of the image forming unit 3 will be described later with reference to FIG. Further, the image forming unit 3 includes a conveyance guide 36 on the downstream side in the conveyance direction of the paper P (left side in FIG. 1) with respect to the recording head 34.

  The transport guide 36 guides the paper P discharged from the transport belt 32 to the paper discharge unit 5. The paper discharge unit 5 includes a discharge roller pair 51 and a discharge tray 52. The discharge tray 52 is fixed to the apparatus casing 100 so as to protrude outward from the discharge port 11 formed in the apparatus casing 100.

  The discharge roller pair 51 sends the paper P that has passed through the conveyance guide 36 toward the discharge port 11. The discharge tray 52 guides the paper P sent out by the discharge roller pair 51. The paper P sent out by the discharge roller pair 51 is discharged to the outside of the apparatus housing 100 through the discharge port 11 formed on one side surface (left side surface in FIG. 1) of the apparatus housing 100. The discharge tray 52 stacks and stores the paper P discharged from the discharge port 11.

  Next, the image forming unit 3 will be described with reference to FIG. FIG. 2 is a diagram showing the configuration of the image forming unit 3 shown in FIG.

  As shown in FIG. 2, the image forming unit 3 includes a transport unit 31, a negative pressure applying unit 33, a recording head 34, and a plate-like member 35. Each of the four types of recording heads 34a, 34b, 34c, and 34d is provided with a plurality of nozzles (not shown). Ink is ejected from the plurality of nozzles to form images such as characters and figures on the paper P. Since the recording heads 34a, 34b, 34c, and 34d have substantially the same configuration, they may be collectively referred to as the recording head 34.

  The transport unit 31 transports the paper P in a predetermined direction (leftward in FIG. 2), and includes a belt speed detection roller 311, a suction roller 312, a drive roller 313, a tension roller 314, a pair of guide rollers 315, and A transport belt 32 is provided.

  The transport unit 31 is disposed in the apparatus housing 100 so as to face the four types of recording heads 34 (34a, 34b, 34c, and 34d). The conveyance belt 32 is stretched around a belt speed detection roller 311, a driving roller 313, a tension roller 314, and a pair of guide rollers 315. The transport belt 32 is driven in the transport direction of the paper P (counterclockwise in FIG. 2) and transports the paper P. The transport belt 32 corresponds to an example of an “endless belt”.

  The tension roller 314 applies tension to the conveyance belt 32 so that the conveyance belt 32 does not bend.

  The belt speed detection roller 311 is arranged on the upstream side (right side in FIG. 2) in the conveyance direction of the paper P with respect to the negative pressure application unit 33, and rotates due to the frictional force with the conveyance belt 32. The belt speed detection roller 311 includes a pulse plate (not shown), and the pulse plate rotates integrally with the belt speed detection roller 311. By measuring the rotational speed of the pulse plate, the rotational speed of the conveyor belt 32 is detected.

  The drive roller 313 is disposed on the downstream side (left side in FIG. 1) in the transport direction of the paper P with respect to the negative pressure application unit 33. Preferably, the driving roller 313 is arranged so as to maintain the flatness of the conveyance belt 32 at a position facing the recording head 34 together with the belt speed detection roller 311.

  The driving roller 313 is rotationally driven by a motor (not shown), and rotates the conveying belt 32 in the counterclockwise direction of FIG.

  The pair of guide rollers 315 are disposed below the negative pressure application unit 33 and form a space below the negative pressure application unit 33. By arranging in this way, contact between the conveyance belt 32 and the negative pressure application unit 33 below the negative pressure application unit 33 can be prevented.

  The four types of recording heads 34 (34a, 34b, 34c, and 34d) are arranged in parallel from the upstream side to the downstream side in the transport direction of the paper P. Each of the recording heads 34a, 34b, 34c, and 34d includes a plurality of nozzles (not shown) arranged in the width direction of the transport belt 32 (in FIG. 2, the direction orthogonal to the paper surface). The recording heads 34a, 34b, 34c, and 34d are called a line type. That is, the ink jet recording apparatus 1 is a line head type ink jet recording apparatus.

  The negative pressure application unit 33 applies a negative pressure to the paper P via the transport belt 32 and causes the paper P to be attracted to the transport belt 32. Further, the negative pressure application unit 33 is disposed on the back surface side (lower side in FIG. 2) of the conveyance belt 32 so as to face the four types of recording heads 34 via the conveyance belt 32. The negative pressure application unit 33 includes an air circulation chamber 331, a guide member 332 that covers the upper surface opening of the air circulation chamber 331, a negative pressure generation unit 336, and an exhaust port 337.

  The suction roller 312 is a driven roller. The suction roller 312 is disposed to face the guide member 332 via the transport belt 32, guides the paper P sent from the registration roller pair 44 onto the transport belt 32, and causes the transport belt 32 to suck the paper P.

  The guide member 332 supports the paper P via the transport belt 32. The guide member 332 corresponds to an example of a “conveyance plate”. Further, a through hole 335 is formed in the guide member 332. The guide member 332 is made of, for example, a metal material. Specifically, as the material of the guide member 332, an aluminum die cast, a pressed plate, or the like can be used. Alternatively, as the material of the guide member 332, a resin excellent in slidability with the transport belt 32 can be selected.

  In the present embodiment, for the sake of convenience, the negative pressure application unit 33 is described as including the guide member 332. However, as described above, the guide member 332 supports the conveyance belt 32, so the conveyance unit 31 supports the guide member 332. It may be described as provided.

  The air circulation chamber 331 is formed by a bottomed cylindrical box-shaped member whose upper surface is open. The upper surface of the side wall constituting the air circulation chamber 331 is fixed to the guide member 332. The negative pressure generator 336 is disposed below the air circulation chamber 331. On the bottom wall of the box-shaped member constituting the air circulation chamber 331, an exhaust port 337 is disposed on the downstream side (lower side in FIG. 2) of the negative pressure generating unit 336 with respect to the air flow. When the negative pressure generating unit 336 is driven, a negative pressure is generated in the air circulation chamber 331, and the sheet P is sucked toward the conveying belt 32 through the guide member 332 and the conveying belt 32 by this negative pressure. The

  The negative pressure generator 336 generates a negative pressure in the air circulation chamber 331, and is, for example, a fan. However, the negative pressure generator 336 is not limited to a fan, and may be a vacuum pump, for example. The air circulation chamber 331 is in a negative pressure state (for example, the differential atmospheric pressure from the atmospheric pressure is about 0.005 atm≈500 Pa) by the negative pressure generating unit 336.

  A plurality (two in this embodiment) of the plate-like members 35 are arranged on the upstream side (the right side in FIG. 2) of the paper P in the transport direction with respect to the recording head 34. In other words, the two plate-like members 351 and 352 are disposed between the recording head 34 a and the suction roller 312, respectively. The plate-like members 351 and 352 are fixed at both ends in the width direction of the plate-like member 35 (direction perpendicular to the paper surface in FIG. 3) by, for example, a fixing member extending from the apparatus housing 100 shown in FIG. The plate-like member 35 (351, 352) corresponds to an example of a “space forming portion”. The space between the plate-like member 35 and the conveyor belt 32 is a narrow space 35a described later.

  Next, the operation of the inkjet recording apparatus 1 will be described with reference to FIG. The paper feed roller 22 takes out the paper P from the paper feed cassette 21. The taken paper P is guided to the first transport roller pair 42 by the guide plate 23.

  The paper P is sent into the paper transport path 41 by the first transport roller pair 42 and is transported in the transport direction of the paper P by the second transport roller pair 43. Then, the sheet P comes into contact with the registration roller pair 44 and stops, and skew correction is performed. Then, the sheet P is sent to the image forming unit 3 by the registration roller pair 44 in accordance with the image forming timing.

  The paper P is guided onto the transport belt 32 by the suction roller 312 and is attracted to the transport belt 32. The paper P is preferably guided to the transport belt 32 so that the center of the paper P in the width direction coincides with the center of the transport belt 32 in the width direction. The sheet P covers a part of a large number of suction holes 321 (see FIG. 4) formed in the transport belt 32. The negative pressure application unit 33 sucks air through the guide member 332 and the conveyor belt 32, and a negative pressure is generated in the air circulation chamber 331. As a result, negative pressure acts on the paper P, and the paper P is attracted to the transport belt 32. The paper P is transported in the transport direction of the paper P as the transport belt 32 moves.

  Each portion of the paper P is continuously conveyed by the conveyance belt 32 to positions facing the four types of recording heads 34a, 34b, 34c, and 34d. During this time, ink of each color is ejected from the four types of recording heads 34a, 34b, 34c, and 34d toward the paper P being transported by the transport belt 32. As a result, an image is formed on the paper P.

  The paper P is transported from the transport belt 32 to the transport guide 36. The sheet P that has passed through the conveyance guide 36 is sent in the direction of the discharge port 11 by the discharge roller pair 51, guided to the discharge tray 52, and discharged to the outside of the apparatus housing 100 through the discharge port 11.

<First Embodiment>
Next, with reference to FIG. 3, the structure which concerns on 1st Embodiment of the plate-shaped member 35 is demonstrated. FIG. 3 is a diagram illustrating a configuration according to the first embodiment of the plate-like member 35 (351, 352) and the guide member 332 shown in FIG.

  As shown in FIG. 3, the plate-like members 351 and 352 are disposed in parallel with the upper surface of the conveyance belt 32 so as to face the upper surface of the conveyance belt 32 in the conveyance unit 31. A narrow space 371 is formed between the lower surface of the plate member 351 and the upper surface of the transport belt 32. In the narrow space 371, the velocity of the airflow flowing into the narrow space 371 from the space around the narrow space 371 is greater after flowing into the narrow space 371 than before flowing into the narrow space 371. Thus, a distance H11 in a direction orthogonal to the upper surface of the transport belt 32 is set. In other words, the distance H11 is the vertical length (distance) of the narrow space 371. Specifically, in the narrow space 371, the vertical distance H11 between the lower surface of the plate-like member 351 and the upper surface of the transport belt 32 is a preset threshold distance HS (for example, 3 mm) or less (for example, 2 mm).

  Similarly, a narrow space 372 is formed between the lower surface of the plate-like member 352 and the upper surface of the transport belt 32. In the narrow space 372, the velocity of the airflow flowing into the narrow space 372 from the space around the narrow space 372 is greater than before flowing into the narrow space 372 than before flowing into the narrow space 372. Is set to a distance H21 in a direction orthogonal to the upper surface of the conveyor belt 32. In other words, the distance H21 is the vertical length (distance) of the narrow space 372. Specifically, in the narrow space 372, the vertical distance H21 between the lower surface of the plate-like member 352 and the upper surface of the conveyor belt 32 is set to a preset threshold distance HS or less (for example, 2 mm). Has been.

  Further, at least the lower surface of the plate-like member 35 (351, 352) is a grounded conductor (for example, a metal such as stainless steel). The upper surface of the conveyor belt 32 that is in contact with the guide member 332 corresponds to an example of a “recording medium placement surface”.

  In the above description with reference to FIG. 3, the case where the thickness of the paper P is sufficiently thin compared to the distances H11 and H21 of the narrow spaces 371 and 372 has been described, but depending on the thickness of the paper P It is preferable to change the distances H11 and H21 of the narrow spaces 371 and 372. Specifically, for example, a plate shape corresponding to the thickness of the paper P so that the distance between the upper surface of the paper P and the lower surface of the plate-like member 35 (351, 352) is substantially constant (for example, 2 mm). It is preferable to raise and lower the members 351 and 352.

  The plate-like members 351 and 352 have a length in the transport direction of the paper P of, for example, 20 mm. A gap 353 is formed between the plate member 351 and the plate member 352. The gap 353 has a length in the transport direction of the paper P of, for example, 5 mm.

  Next, the configuration of the conveyor belt 32, the guide member 332, and the negative pressure application unit 33 will be described with reference to FIG. FIG. 4 is a cut perspective view showing configurations of the conveyance belt 32, the guide member 332, and the negative pressure application unit 33 shown in FIG.

  As shown in FIG. 4, the conveyance belt 32, the guide member 332, the air circulation chamber 331, and the negative pressure generation unit 336 are arranged from the upper side to the lower side. A number of suction holes 321 are formed in the transport belt 32.

  Here, the suction holes 321 formed in the transport belt 32 will be described. As shown in FIG. 4, a plurality of suction holes 321 are formed in the conveyor belt 32 at substantially equal intervals. The diameter of the suction hole 321 is, for example, 2 mm, and the distance from the adjacent suction hole 321 is, for example, 8 mm.

  In addition, a plurality of grooves 334 are formed on the upper surface of the guide member 332 (the surface on the conveying belt 32 side). The groove 334 is formed in an oval shape extending in the conveyance direction of the paper P. Further, a through hole 335 is formed in the guide member 332. The through-hole 335 causes the negative pressure in the air circulation chamber 331 to act on the paper P through the suction hole 321. The through hole 335 is a hole that penetrates the guide member 332 in the thickness direction. The cross section of the through hole 335 is circular.

  Returning to FIG. 3 again, the flow of air near the narrow space 371 and the narrow space 372 will be described. Air that has flowed into the narrow space 371 from the upstream side (right side in FIG. 3) and the downstream side (left side in FIG. 3) of the sheet P with respect to the plate-like member 351 flows into the narrow space 371 and the plurality of suction holes 321 and the plurality of suction holes 321. The air flows into the air circulation chamber 331 through the through hole 335. In other words, since the air circulation chamber 331 is in a negative pressure state by the negative pressure generation unit 336, the air circulation chamber 331 is connected to the air circulation chamber 331 via the plurality of suction holes 321 and the through holes 335. Air flows from 371. Further, since air flows into the air circulation chamber 331 from the narrow space 371, the narrow space is formed from the upstream side (right side in FIG. 3) and the downstream side (left side in FIG. 3) of the sheet P with respect to the plate member 351. Air flows into the space 371.

  Similarly, air that has flowed into the narrow space 372 from the upstream side (right side in FIG. 3) and the downstream side (left side in FIG. 3) of the sheet P with respect to the plate-like member 352 flows into the narrow space 372, and Then, the air flows into the air circulation chamber 331 through the through hole 335. In other words, since the air circulation chamber 331 is in a negative pressure state by the negative pressure generator 336, the air circulation chamber 331 is narrowed into the air circulation chamber 331 via the plurality of suction holes 321 and the plurality of through holes 335. Air flows from the gap space 372. Further, since air flows from the narrow space 372 into the air circulation chamber 331, the narrow space is formed from the upstream side (right side in FIG. 3) and the downstream side (left side in FIG. 3) of the sheet P with respect to the plate member 352. Air flows into the space 372.

  As described above, air flows along the arrows F01 and F02 shown in FIG. Since the distances H11 and H12 of the narrow gap spaces 371 and 372 are set to a predetermined threshold distance HS (for example, 3 mm) or less (in the present embodiment, the distances H11 and H12 are 2 mm). The wind speed in the narrow spaces 371 and 372 increases. The wind speed in the narrow gap spaces 371 and 372 is preferably, for example, 6.0 m / second or more.

  Further, as described above, the wind indicated by the arrow F01 blows in the narrow space 371 from the upstream side to the downstream side in the conveyance direction of the paper P (to the left in FIG. 3). In addition, the paper dust PD adhering to the front end (left end in FIG. 3) of the paper P can be removed, and the removed paper dust PD can be collected in the air circulation chamber 331. Further, since the wind indicated by the arrow F02 blows from the downstream side to the upstream side in the conveyance direction of the paper P in the narrow space 372 (to the right in FIG. 3), as shown in FIG. The paper dust PD attached to the rear end (right end in FIG. 3) can be removed, and the removed paper dust PD can be collected in the air circulation chamber 331. Therefore, the paper dust adhering to the paper P can be effectively removed.

  Further, as described above, since the plate-like members 351 and 352 are grounded conductors, the plate-like members 351 and 352 are not charged. Therefore, even when the paper dust is charged, the adhesion of the paper dust to the plate-like members 351 and 352 can be suppressed.

  Next, the groove 334 and the through hole 335 formed in the guide member 332 will be described with reference to FIG. FIG. 5 is a plan view showing the configuration of the guide member 332 shown in FIG. As shown in FIG. 5, the guide member 332 has a plurality of rows of grooves 334 formed in the width direction of the guide member 332 (the vertical direction in FIG. 5). In addition, a through hole 335 is formed in each of the grooves 334 at a substantially central position in the conveyance direction of the paper P (left and right direction in FIG. 5).

  The broken lines shown in FIG. 5 indicate the positions of the plate-like members 351 and 352 projected onto the guide member 332. Through holes 335 are formed in a row at the center of the guide member 332 in the conveyance direction (left and right direction in FIG. 5) of the sheet P of the projection images of the plate-like members 351 and 352, respectively. A groove 334 communicating with the through hole 335 formed on the upstream side in the transport direction of the paper P (left side in FIG. 5) is upstream in the transport direction of the paper P in the projection image of the plate-like member 351 (left side in FIG. 5). The paper P extends further upstream than the end position in the transport direction of the paper P, and the transport direction of the paper P further than the position of the downstream end (right side in FIG. 5) of the paper P in the projection image of the plate-like member 351. It extends downstream. Similarly, the groove 334 communicating with the through-hole 335 formed on the downstream side in the transport direction of the paper P (right side in FIG. 5) is more than the upstream end position in the transport direction of the paper P in the projection image of the plate-like member 352. Furthermore, it extends to the upstream side in the transport direction of the paper P, and further extends downstream in the transport direction of the paper P from the position of the downstream end in the transport direction of the paper P in the projection image of the plate-like member 352.

  Next, the groove 334 and the through hole 335 formed in the guide member 332 will be described with reference to FIG. 6 is a plan view and a cross-sectional view showing the configuration of the groove 334 and the through hole 335 shown in FIG. 6A is a plan view showing the configuration of the groove 334 and the through hole 335, and FIG. 6B is a cross-sectional view taken along line AA showing the configuration of the groove 334 and the through hole 335 shown in FIG. FIG.

  As shown in FIG. 6A, a through-hole 335 is formed at a substantially central position in the groove 334 in the conveyance direction of the paper P (left-right direction in FIG. 6A). As shown in FIG. 6B, since the groove 334 is formed in communication with the through hole 335, the negative pressure applied from the air circulation chamber 331 via the through hole 335 is formed in the groove 334. It also affects the area where it is.

  As described above, since the groove 334 is formed at a position facing the plate-like members 351 and 352, the negative pressure applied from the air circulation chamber 331 via the through-hole 335 forms the groove 334. It also affects the area. Therefore, since the air can flow more easily along the arrows F01 and F02 shown in FIG. 3, paper dust can be more effectively removed.

  Returning to FIG. 4, the positional relationship between the suction hole 321 and the groove 334 will be described. A plurality of rows of suction holes 321 arranged in the transport direction of the paper P are formed in the width direction of the transport belt 32 (a direction orthogonal to the transport direction of the paper P). The suction holes 321 are arranged in a staggered manner. As shown in FIG. 4, the rows of the plurality of suction holes 321 of the transport belt 32 are respectively arranged corresponding to the rows of the plurality of grooves 334.

  The plurality of grooves 334 are formed so as to face at least two suction holes 321 in the transport direction of the paper P, respectively. As the transport belt 32 moves, the opposing suction holes 321 are replaced one by one in the plurality of grooves 334, respectively.

  The air circulation chamber 331 communicates with the suction hole 321 of the transport belt 32 through the through hole 335 and the groove 334 of the guide member 332.

  As described above, since the negative pressure is applied to the suction hole 321 of the transport belt 32, the transport belt 32 can suck and transport the paper P.

  Next, referring to FIG. 7, in the configuration of the plate-like members 35 (351, 352) and the guide member 332 according to the first embodiment shown in FIG. 3, the leading end of the sheet P (the left end in FIG. 7). A description will be given of the air flow in the narrow space 371, 372 in the case where is located in the vicinity immediately above the through hole 335 (through hole 3352) formed immediately below the plate-like member 352. FIG. 7 is a diagram illustrating the air flow in the narrow spaces 371 and 372 when the leading edge of the paper P is positioned in the vicinity of the position immediately above the through hole 3352 in the configuration of the first embodiment illustrated in FIG. 3. As shown in FIG. 7, the through hole 3351 is a through hole 335 formed immediately below the plate member 351, and the through hole 3352 is a through hole 335 formed immediately below the plate member 352.

  When the leading edge of the sheet P is located in the vicinity of the position immediately above the through hole 3352, the negative pressure from the through hole 3351 reaches the suction hole 321 formed in the transport belt 32 through the groove 334. However, among the suction holes 321 formed in the transport belt 32, the suction hole 321 at the center in the width direction (the direction perpendicular to the paper surface in FIG. 3) is blocked by the paper P placed on the transport belt 32. ing. Therefore, the negative pressure from the through hole 3351 hardly generates an air flow in the narrow space 371 or 372.

  The negative pressure from the through hole 3351 reaches the suction hole 321 formed in the transport belt 32 through the groove 334. Of the suction holes 321 formed in the transport belt 32, the suction hole 321 at the center in the width direction (the direction perpendicular to the paper surface in FIG. 7) is upstream in the transport direction of the paper P with respect to the through hole 335 (FIG. 7). On the right side, the sheet P is blocked by the paper P placed on the conveyor belt 32. On the other hand, among the suction holes 321 formed in the transport belt 32, the suction hole 321 at the center in the width direction (the direction perpendicular to the paper surface in FIG. 7) is downstream in the transport direction of the paper P with respect to the through-hole 335 ( On the left side in FIG. 7, it is open.

  Therefore, due to the negative pressure from the through hole 3352, air is sucked through the suction hole 321 on the downstream side (left side in FIG. 7) in the conveyance direction of the paper P with respect to the through hole 3352, and the paper P An air flow F12 is generated from the upstream side to the downstream side in the transport direction (from the right side to the left side in FIG. 7).

  As described above, the distance H21 of the narrow space 372 is set to a predetermined threshold distance HS (for example, 3 mm) or less (in this embodiment, the distance H21 is 2 mm). The wind speed of the air flow F12 at 372 increases. Therefore, an air flow F11 is also generated in the narrow space 371 from the upstream side to the downstream side in the conveyance direction of the paper P (from the right side to the left side in FIG. 7).

  Further, as described above, since the distance H11 of the narrow space 371 is set to be equal to or smaller than a preset threshold distance HS (in this embodiment, the distance H11 is 2 mm), the air in the narrow space 371 The wind speed of the flow F11 increases.

  Further, since a gap 353 is formed between the plate-like member 351 and the plate-like member 352, a part of the air flow F11 flows upward from the gap 353 and is part of the air flow F12. The part flows from above the gap 353. Therefore, a part of the air flow having a high wind speed in the narrow space 371 flows out from the gap 353, and thus the wind speed of the air flow F12 in the narrow space 372 decreases.

  Accordingly, since the air velocity F12 of the air flow F12 in the narrow space 372 is reduced by the gap 353, the air velocity of the air flow F13 flowing toward the recording head 34 can be reduced. As a result, the influence of the air flow F13 on the print quality by the recording head 34 can be suppressed.

  In the first embodiment, the length of the plate members 351 and 352 in the conveyance direction of the paper P is 20 mm, and the length of the gap 353 in the conveyance direction of the paper P is 5 mm. However, the larger the length of the gap 353 in the transport direction of the paper P, the more effectively the influence of the air flow F12 on the print quality by the recording head 34 can be suppressed.

Second Embodiment
Next, with reference to FIG. 8, the structure of the plate-shaped members 351a and 352a and the guide member 332a according to the second embodiment will be described. FIG. 8 is a diagram illustrating the configuration of the plate-like member and the guide member shown in FIG. 2 according to the second embodiment. In the second embodiment, the guide member 332a does not have a groove, and the length of the through hole 335a in the transport direction of the paper P is substantially the same as the length of the plate-shaped members 351a and 352a in the transport direction of the paper P. This is different from the first embodiment. Since the plate-like members 351a and 352a according to the second embodiment have the same configuration as the plate-like members 351 and 352 according to the first embodiment, respectively, description thereof is omitted.

  In the guide member 332a according to the second embodiment, the length of the through hole 335a (335a1, 335a2) in the transport direction of the paper P is substantially the same as the length of the plate-shaped members 351a, 352a in the transport direction of the paper P. Through holes 335a (335a1, 335a2) are formed. As shown in FIG. 8, the through-hole 335a1 is a through-hole 335a formed directly under the plate-like member 351a, and the through-hole 335a2 is a through-hole 335a formed directly under the plate-like member 352a. Moreover, the groove | channel is not formed in the guide member 332a which concerns on 2nd Embodiment.

  In the second embodiment, the flow of air in the narrow spaces 371a and 372a in the case where the leading end of the paper P (the left end in FIG. 8) is located in the vicinity immediately above the through hole 335a2 will be described. The narrow space 371a is a space formed between the upper surface of the transport belt 32 and the plate-like member 351a. The narrow space 372a is a space formed between the upper surface of the conveyor belt 32 and the plate-like member 352a. Further, the narrow gap space 371a is located upstream of the narrow gap space 372a in the conveyance direction of the paper P (right side in FIG. 8). The distance H12 is a vertical distance of the narrow space 371a. The distance H22 is the vertical distance of the narrow space 372a.

  In the second embodiment, similarly to the first embodiment, the negative pressure from the through hole 335a2 causes the through hole 335a2 to pass through the suction hole 321 on the downstream side (left side in FIG. 8) in the transport direction of the paper P. Air is sucked and an air flow F22 is generated in the narrow space 372a from the upstream side to the downstream side in the conveyance direction of the paper P (from the right side to the left side in FIG. 8).

  In addition, since the distance H22 of the narrow space 372a is set to a preset threshold distance HS (for example, 3 mm) or less (in this embodiment, the distance H22 is 2 mm), the air in the narrow space 372a. The wind speed of the flow F22 increases. Therefore, an air flow F21 is also generated in the narrow space 371a from the upstream side to the downstream side in the conveyance direction of the paper P (from the right side to the left side in FIG. 8).

  Further, as described above, the vertical distance H12 of the narrow space 371a is set to be equal to or smaller than a preset threshold distance HS (in the present embodiment, the distance H12 is 2 mm). The wind speed of the air flow F21 in 371a increases.

  Further, since a gap 353a is formed between the plate-like member 351a and the plate-like member 352a, a part of the air flow F21 flows upward from the gap 353a and one part of the air flow F22. The part flows from above the gap 353a. Therefore, a part of the air flow in the narrow space 371a flows out from the gap 373a, so that the wind speed of the air flow F22 in the narrow space 372a decreases.

  Therefore, the wind speed of the air flow F22 in the narrow space 372a is reduced by the gap 353a, so that the wind speed of the air flow F23 flowing toward the recording head 34 can be reduced. As a result, the influence of the air flow F23 on the print quality by the recording head 34 can be suppressed.

  Further, since the length of the through-hole 335a in the conveyance direction of the paper P is formed so as to substantially coincide with the length of the plate-shaped member 351a in the conveyance direction of the paper P, the leading end of the paper P (the left end in FIG. 8). Reaches the downstream end (the left end in FIG. 8) of the narrow space 372a, the suction hole 321 at the center in the width direction (the direction perpendicular to the paper surface in FIG. 8) is placed on the transport belt 32. The paper P is blocked. Therefore, since the air flow F23 is further suppressed, the influence of the recording head 34 on the print quality can be further suppressed.

<Third Embodiment>
Next, the configuration of the plate-like members 351b and 352b and the guide member 332b according to the third embodiment will be described with reference to FIG. FIG. 9 is a diagram illustrating a configuration according to the third embodiment of the plate-like member and the guide member illustrated in FIG. 2. The third embodiment is different from the first embodiment in that the length of the groove 334b in the conveyance direction of the paper P is substantially the same as the length of the plate-like members 351b and 352b in the conveyance direction of the paper P. To do. Since the plate-like members 351b and 352b according to the third embodiment have the same configuration as the plate-like members 351 and 352 according to the first embodiment, respectively, description thereof is omitted.

  The guide member 332b according to the third embodiment is formed such that the length of the groove 334b in the conveyance direction of the paper P is substantially the same as the length of the plate-like members 351b and 352b in the conveyance direction of the paper P. Further, the guide member 332b according to the third embodiment has a through hole 335b formed at the center of each groove 334b in the conveyance direction of the paper P. As shown in FIG. 9, the through hole 335b1 is a through hole 335b formed directly under the plate-like member 351b, and the through-hole 335b2 is a through hole 335b formed directly under the plate-like member 352b.

  In the third embodiment, the flow of air in the narrow spaces 371b and 372b in the case where the front end (the left end in FIG. 9) of the paper P is positioned in the vicinity immediately above the through hole 335b2 will be described. The narrow space 371b is a space formed between the upper surface of the transport belt 32 and the plate-like member 351b. The narrow space 372b is a space formed between the upper surface of the transport belt 32 and the plate-like member 352b. Further, the narrow gap space 371b is located on the upstream side (right side in FIG. 9) in the transport direction of the paper P with respect to the narrow gap space 372b. The distance H13 is a vertical distance of the narrow space 371b. The distance H23 is a distance in the vertical direction of the narrow space 372b.

  In the third embodiment, similarly to the first embodiment, the negative pressure from the through-hole 335b2 causes the through-hole 335b2 to pass through the suction hole 321 on the downstream side (left side in FIG. 9) in the transport direction of the paper P. Air is sucked and an air flow F32 is generated in the narrow space 372b from the upstream side to the downstream side in the conveyance direction of the paper P (from the right side to the left side in FIG. 9).

  In addition, since the vertical distance H23 of the narrow space 372b is set to be equal to or less than a preset threshold distance HS (for example, 3 mm) (in this embodiment, the distance H23 is 2 mm), the narrow space The wind speed of the air flow F32 in 372b increases. Therefore, an air flow F31 is also generated in the narrow space 371b from the upstream side to the downstream side in the conveyance direction of the paper P (from the right side to the left side in FIG. 9).

  In addition, as described above, the distance H13 of the narrow space 371b is set to be equal to or less than a preset threshold distance HS (in this embodiment, the distance H13 is 2 mm), and thus the air in the narrow space 371a. The wind speed of the flow F31 increases.

  Further, since a gap 353b is formed between the plate-like member 351b and the plate-like member 352b, a part of the air flow F31 flows upward from the gap 353b and a part of the air flow F32 is provided. The part flows in from above the gap 353b. Therefore, a part of the air flow having a high wind speed in the narrow space 371b flows out from the gap 373b, and thus the wind speed of the air flow F32 in the narrow space 372b is reduced.

  Therefore, the wind speed of the air flow F23 in the narrow space 372b is reduced by the gap 353b, so that the wind speed of the air flow F33 flowing toward the recording head 34 can be reduced. As a result, the influence of the air flow F33 on the print quality by the recording head 34 can be suppressed.

  Further, since the length of the groove 334b in the conveyance direction of the paper P is formed to substantially coincide with the length of the plate-shaped member 351b in the conveyance direction of the paper P, the leading end of the paper P (the left end in FIG. 9) is formed. When reaching the downstream end (the left end in FIG. 9) of the narrow space 372b, the suction hole 321 at the center in the width direction (the direction perpendicular to the paper surface in FIG. 9) is placed on the transport belt 32. The paper P is blocked. Therefore, since the air flow F33 is further suppressed, the influence of the recording head 34 on the print quality can be further suppressed.

<Fourth embodiment>
Next, the configuration of the plate-like members 351c and 352c and the guide member 332c according to the fourth embodiment will be described with reference to FIG. FIG. 10 is a diagram illustrating a configuration according to the fourth embodiment of the plate-shaped member and the guide member illustrated in FIG. 2. The fourth embodiment is different from the first embodiment in that the plate-like member 352c is arranged such that the distance from the upper surface of the transport belt 32 is larger than the plate-like member 351c. Since the guide member 332c according to the fourth embodiment has the same configuration as the guide member 332 according to the first embodiment, the description thereof is omitted. As shown in FIG. 10, the through hole 335c1 is a through hole 335c formed directly under the plate-like member 351c, and the through-hole 335c2 is a through hole 335c formed directly under the plate-like member 352c.

  The narrow space 371c is a space formed between the upper surface of the transport belt 32 and the plate-like member 351c. The narrow space 372c is a space formed between the upper surface of the conveyor belt 32 and the plate member 352c. Further, the narrow space 371c is located on the upstream side (right side in FIG. 9) in the conveyance direction of the paper P with respect to the narrow space 372c. The distance H14 is the vertical distance of the narrow space 371c. The distance H24 is a vertical distance of the narrow space 372c.

  The plate-like member 352c is arranged so that the distance from the upper surface of the transport belt 32 is larger than that of the plate-like member 351c. In other words, the distance H24 is greater than the distance H14. For example, the distance H14 is set to 2 mm, and the distance H24 is set to 4 mm. A gap 353c is formed between the plate member 351c and the plate member 352c. The gap 353c has a length in the conveyance direction of the paper P set to 5 mm.

  In the fourth embodiment shown in FIG. 10, the flow of air in the narrow gap spaces 371c and 372c in the case where the leading end of the paper P (the left end in FIG. 10) is located immediately above the through hole 335c2 will be described.

  In the fourth embodiment, similarly to the first embodiment, the negative pressure from the through hole 335c2 causes the suction hole 321 on the downstream side (left side in FIG. 10) in the transport direction of the paper P to the through hole 335c2. Air is sucked, and an air flow F42 is generated in the narrow space 372c from the upstream side to the downstream side in the conveyance direction of the paper P (from the right side to the left side in FIG. 10).

  Further, since the distance H24 of the narrow space 372c is set to 4 mm, for example, the increase in the wind speed of the air flow F42 in the narrow space 372c is small as compared with the first embodiment. In addition, the narrow space 371c positioned on the upstream side (right side in FIG. 10) of the air flow F42 also flows from the upstream side to the downstream side in the conveyance direction of the paper P (from the right side to the left side in FIG. 10). Will occur.

  Further, as described above, the distance H14 of the narrow space 371c is set to be equal to or smaller than a preset threshold distance HS (in the present embodiment, the distance H14 is 2 mm), and thus the air in the narrow space 371c. The wind speed of the flow F41 increases.

  Further, since a gap 353c is formed between the plate-like member 351c and the plate-like member 352c, a part of the air flow F41 flows upward from the gap 353c and is part of the air flow F42. The part flows from above the gap 353c. Therefore, a part of the air flow having a large wind speed in the narrow space 371c flows out from the gap 373c, and thus the wind speed of the air flow F42 in the narrow space 372c is reduced.

  Accordingly, the gap 353c is formed, and the vertical distance H24 of the narrow space 372c is set to be larger than the vertical distance H14 of the narrow space 371c. Therefore, the air flow F42 in the narrow space 372c. However, the wind speed of the air flow F43 flowing toward the recording head 34 can be reduced. As a result, the influence of the air flow F43 on the print quality by the recording head 34 can be suppressed.

  Further, the length of the gap 353c in the conveyance direction of the paper P is set to 5 mm as in the first to third embodiments, but the plate-like member 352c is disposed above the plate-like member 351c. Therefore, it is wider than the gaps 353, 353a and 353b in the first to third embodiments shown in FIGS. Accordingly, since the air flow easily flows out from the gap 353c and easily flows from above the gap 353c, the influence on the print quality by the recording head 34 can be further suppressed.

<First comparative form>
Next, a comparative example will be described with reference to FIGS. 11 and 12. The comparative form described below is a form in which the influence on the print quality by the recording head 34 may be greater than in the first to fourth embodiments. FIG. 11 is a diagram showing a configuration according to a first comparative form of the plate-like member and the guide member shown in FIG. The first comparative embodiment is different from the first embodiment in that the plate member is a single plate member. Since the guide member 332d according to the first comparative embodiment has the same configuration as the guide member 332 according to the first embodiment, the description thereof is omitted.

  The plate-like member 35d according to the first comparative embodiment is a single plate-like member. A narrow space 37d is formed between the lower surface of the plate member 35d and the upper surface of the conveyor belt 32. In the narrow space 37d, the vertical distance H15 is set to be equal to or smaller than a preset threshold distance HS (for example, 2 mm). As shown in FIG. 11, the through hole 335d1 is a through hole 335d formed on the upstream side of the two through holes 335d formed below the plate-like member 35d, and the through hole 335d2 is formed on the downstream side. It is the formed through-hole 335d.

  In the configuration of the plate-shaped member 35d and the guide member 332d according to the first comparative form, the air in the narrow space 37d when the leading end (the left end in FIG. 11) of the sheet P is located in the vicinity immediately above the through-hole 335d2. The flow will be described. The narrow space 37d is a space formed between the upper surface of the transport belt 32 and the plate-like member 35d. The distance H15 is the vertical distance of the narrow space 37d.

  In the first comparative embodiment, similarly to the first embodiment, the negative pressure from the through hole 335d2 causes the through hole 335d to pass through the suction hole 321 on the downstream side (left side in FIG. 11) in the transport direction of the paper P. Air is aspirated. Therefore, an air flow F52 is generated in the narrow space 37d from the upstream side to the downstream side in the conveyance direction of the paper P (from the right side to the left side in FIG. 11).

  Further, since the distance H15 of the narrow space 37d is set to be equal to or smaller than a preset threshold distance HS (in the present embodiment, the distance H15 is 2 mm), the wind speed of the air flow F52 in the narrow space 37d. Will increase.

  Therefore, since the air flow F52 with increased wind speed flows from the upstream side to the downstream side in the conveyance direction of the paper P (from the right side to the left side in FIG. 11) through the narrow space 37d, the air flow F52 is directed toward the recording head 34. The wind speed of the flowing air does not decrease. As a result, the air flow F53 separated from the air flow F52 may blow into the space between the recording head 34 and the conveyance belt 32, and may affect the print quality of the recording head 34.

<Second comparative form>
Next, the second comparative embodiment will be described with reference to FIG. FIG. 12 is a diagram showing a configuration according to a second comparative form of the plate-like member and the guide member shown in FIG. The second comparative embodiment relates to the first embodiment in that the groove formed below the plate-like member 351e and the groove formed below the plate-like member 352 are connected to form a groove 334e. Different from the groove 334. Since the plate-like members 351e and 352e according to the second comparative embodiment have the same configuration as the plate-like members 351 and 352 according to the first embodiment shown in FIGS. 3 and 7, the description thereof is omitted.

  The guide member 332e according to the second comparative embodiment is the same as the first embodiment in that the groove 334e formed below the plate member 351e communicates with the groove 334e formed below the plate member 352. This is different from the groove 334. As shown in FIG. 10, the through-hole 335e1 is a through-hole 335e formed directly under the plate-like member 351e, and the through-hole 335e2 is a through-hole 335e formed directly under the plate-like member 352e.

  The flow of air in the narrow gap spaces 371e and 372e when the leading end of the paper P (the left end in FIG. 12) is positioned in the vicinity immediately above the through hole 335e2 in the second comparative embodiment will be described. The narrow space 371e is a space formed between the upper surface of the transport belt 32 and the plate-like member 351e. The narrow space 372e is a space formed between the upper surface of the transport belt 32 and the plate-like member 352e. Further, the narrow gap space 371e is located on the upstream side (right side in FIG. 12) in the transport direction of the paper P with respect to the narrow gap space 372e. The distance H16 is a vertical distance of the narrow space 371e. The distance H26 is a distance in the vertical direction of the narrow space 372e.

  In the second comparative embodiment, unlike the first embodiment, in addition to the negative pressure from the through hole 335e2, the negative pressure from the through hole 335e1 causes the downstream side in the transport direction of the paper P to the through hole 335e2 (see FIG. 12, air is sucked through the suction hole 321 on the left side. Accordingly, in the narrow space 372e, an air flow F62 that is faster than that in the first embodiment is generated from the upstream side to the downstream side in the conveyance direction of the paper P (from the right side to the left side in FIG. 12).

  Further, since the distance H26 of the narrow space 372e is set to be equal to or smaller than a preset threshold distance HS (in the present embodiment, the distance H15 is 2 mm), the wind speed of the air flow F62 in the narrow space 372e. Increases further.

  Accordingly, the air flow F62 with increased wind speed flows from the upstream side to the downstream side in the conveyance direction of the paper P (from the right side to the left side in FIG. 12) through the narrow space 37d, and therefore toward the recording head 34. The wind speed of the flowing air does not decrease. As a result, the air flow F63 separated from the air flow F62 may blow into the space between the recording head 34 and the conveyance belt 32, and may affect the print quality of the recording head 34.

  The embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to the above-described embodiment, and can be implemented in various modes without departing from the gist thereof (for example, (1) to (5) shown below). For ease of understanding, the drawings schematically show each component as a main component, and the thickness, length, number, etc. of each component shown in the drawings are different from the actual for convenience of drawing. There is a case. Moreover, the shape, dimension, etc. of each component shown by said embodiment are an example, Comprising: It does not specifically limit, A various change is possible in the range which does not deviate substantially from the structure of this invention.

  (1) In the first to fourth embodiments, the case where the transport belt 32 transports the paper P in the image forming unit 3 has been described. However, the image forming unit 3 may transport the paper P by other methods. For example, the paper P may be transported by a plurality of transport rollers. In this case, it is preferable to apply a negative pressure from between adjacent conveyance rollers.

  (2) In the first to fourth embodiments, the narrow space 371 (371a, 371b, 371c), 372 (372a, 372b, 372c) is a plate-like member 351 (351a, 351b, 351c), 352 (352a, 352b). , 352c), the narrow space 371 (371a, 371b, 371c) and 372 (372a, 372b, 372c) may be formed by other methods. For example, on the upstream side in the transport direction of the paper P with respect to the recording head 34, the head base 37 is formed to protrude toward the transport belt 32, and the narrow gap spaces 371 (371a, 371b, 371c), 372 (372a, 372b, 372c). ) May be formed. In this case, the structure can be simplified.

  In addition, instead of the plate-like members 351 (351a, 351b, 351c), 352 (352a, 352b, 352c), narrow spaces 371 (371a, 371b, 371c), 372 ( 372a, 372b, 372c) may be formed. Specifically, the driving roller and the driven roller disposed at a position substantially parallel to the upper surface of the transport belt 32, and an endless belt stretched between the driving roller and the driven roller, the lower surface of the endless belt, Narrow gap spaces 371 (371a, 371b, 371c) and 372 (372a, 372b, 372c) are formed between the upper surface of the conveyor belt 32. In this case, when the paper dust adheres to the lower surface of the endless belt, the endless belt can be driven to rotate so that the surface to which the paper dust does not adhere is located on the lower side. However, the frequency of removing the paper dust adhering to the endless belt can be reduced.

  (3) In the first to fourth embodiments, the case where the guide member 332 (332a, 332b, 332c) and the air circulation chamber 331 are separate members has been described. However, the guide member 332 (332a, 332b, 332c) The form in which the air circulation chamber 331 is integrally formed may be sufficient. In this case, leakage of negative pressure from the air circulation chamber 331 (inflow of air into the air circulation chamber 331 from the gap between the guide member 332 (332a, 332b, 332c) and the air circulation chamber 331) is prevented. can do.

  (4) In the first to fourth embodiments, the case where two plate-like members 351 (351a, 351b, 351c) and 352 (352a, 352b, 352c) are provided has been described, but three or more plate-like members are provided. The form provided with. As the number of plate members increases, the wind speed in the narrow space can be finely adjusted.

  (5) In the first to fourth embodiments, the length of the two plate-like members 351 (351a, 351b, 351c) and 352 (352a, 352b, 352c) in the transport direction of the paper P is the same. As described above, the length of the two plate-like members 351 (351a, 351b, 351c) and 352 (352a, 352b, 352c) in the transport direction of the paper P may be different. For example, among the two plate-like members 351 (351a, 351b, 351c) and 352 (352a, 352b, 352c), the paper P of the plate-like member 351 (351a, 351b, 351c) on the upstream side in the conveyance direction of the paper P. As the length in the transport direction increases, the paper dust can be efficiently removed.

  The present invention is applicable to an ink jet recording apparatus.

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 2 Paper feed part 3 Image formation part 31 Conveyance part 312 Adsorption roller 32 Conveyance belt 321 Suction hole 33 Negative pressure application part 331 Air circulation chamber 332, 332a, 332b, 332c Guide member (conveyance plate)
334, 334b, 334c Groove 335 (3351, 3352), 335a (335a1, 335a2), 335b (335b1, 335b2), 335c (335c1, 335c2) Through hole 336 Negative pressure generating part 34 (34a, 34b, 34c, 34d) Recording head 35 (351, 352), 35a (351a, 352a), 35b (351b, 352b), 35c (351c, 352c) Plate member (space forming portion)
371, 372, 371a, 372a, 371b, 372b, 371c, 372c Narrow space 36 Transport guide 4 Paper transport section 5 Paper discharge section

Claims (10)

A plurality of recording heads that eject ink onto a recording medium;
A transport unit for transporting the recording medium to an image forming position by the plurality of recording heads;
A space forming portion that forms a narrow space between the recording medium and a mounting surface of the recording medium in the transport portion on the upstream side in the transport direction of the recording medium with respect to the plurality of recording heads;
A negative pressure application unit that applies a negative pressure to the narrow space,
The plurality of recording heads are arranged in a conveyance direction of the recording medium,
In the narrow space, the velocity of the air flow flowing into the narrow space from the space around the narrow space is greater after flowing into the narrow space than before flowing into the narrow space. So that the distance in the direction perpendicular to the placement surface is set,
A plurality of the space forming portions are arranged in the conveyance direction of the recording medium,
Each of the plurality of space forming units is disposed upstream of the recording head in the transport direction of the recording medium, more upstream of the recording medium in the transport direction of the recording medium. apparatus.   The inkjet recording apparatus according to claim 1, wherein the space forming unit forms the narrow space so that a distance in a direction perpendicular to the placement surface in the narrow space is equal to or less than a preset threshold distance. .   The said space formation part is respectively provided with the plate-shaped member which has a plane facing the mounting surface of the said recording medium in the said conveyance part, and substantially parallel to the mounting surface of the said recording medium. 2. An ink jet recording apparatus according to 1.   The inkjet recording apparatus according to claim 3, wherein the plate-like member is a grounded conductor. The transport unit includes an endless belt on which the recording medium is placed,
5. The inkjet recording apparatus according to claim 1, wherein the endless belt is formed with a plurality of holes for adsorbing the recording medium by a negative pressure generated by the negative pressure application unit. The transport unit includes a transport plate that supports the endless belt,
The transport plate is formed with a plurality of through holes,
The inkjet recording apparatus according to claim 5, wherein the negative pressure application unit applies a negative pressure to the narrow space through the through hole.   The inkjet according to claim 6, wherein each of the plurality of space forming portions is formed such that a length of the recording medium in a conveyance direction is substantially coincident with a length of the through hole in the conveyance direction of the recording medium. Recording device.   The ink jet recording apparatus according to claim 6, wherein the transport plate has a groove extending along the transport direction of the recording medium on the endless belt side of the through hole.   The inkjet recording according to claim 8, wherein each of the plurality of space forming portions is formed so that a length of the recording medium in a conveyance direction is substantially coincident with a length of the groove in the conveyance direction of the recording medium. apparatus.   The plurality of the narrow gap spaces formed by the plurality of space forming portions have a larger distance in a direction perpendicular to the placement surface as they are located downstream in the conveyance direction of the recording medium. Item 10. The ink jet recording apparatus according to any one of Items 9.

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