JP2016129985A - Inkjet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively remove paper powder.SOLUTION: An inkjet recording device 1 comprises: a control unit 6; a conveyor section 31; a recording head 34; a negative-pressure application section 33; a space forming section 35; and a first voltage application section 381. The conveyor section 31 mounts a recording medium P on a mount surface 32 and conveys the recording medium P. The recording head 34 delivers ink to the recording medium P. The negative-pressure application section 33 applies a negative pressure to the recording medium P via a plurality of holes 321 formed in the mount surface 32 and attracts the recording medium P onto the mount surface 32. A narrow space 35a is formed between the space formation section 35a and the mount surface 32 upstream, in a conveyance direction of the recording medium P, of the recording head 34. All of or a part of the space formation section 35 is a conductive section 352. The first voltage application section 381 applies a voltage to the conductive section 352. While predetermined processing is ongoing, the control unit 6 controls the first voltage application section 381 to apply the voltage to the conductive section 352.SELECTED DRAWING: Figure 2

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.

  An ink jet recording apparatus according to an aspect of the present invention includes a control unit, a transport unit, a recording head, a negative pressure application unit, a space formation unit, and a first voltage application unit. The transport unit transports a recording medium placed on the mounting surface of the recording medium. The recording head discharges ink onto the recording medium transported by the transport unit to form an image. The negative pressure application unit applies a negative pressure through a plurality of holes formed in the mounting surface, and adsorbs the recording medium conveyed by the conveying unit to the mounting surface. The space forming unit forms a narrow space between the recording head and the mounting surface upstream of the recording head in the transport direction of the recording medium. The space forming part is a conductive part, all or a part of which has conductivity. The first voltage application unit applies a voltage to the conductive unit. 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. The control unit controls the first voltage application unit to apply a voltage to the conductive unit while a predetermined process is being performed.

  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 first diagram illustrating a configuration of an image forming unit illustrated in FIG. 1. It is a figure which shows the structure of the plate-shaped member vicinity shown in FIG. FIG. 3 is a cut perspective view illustrating configurations of a conveyance belt, a guide member, and a negative pressure application unit illustrated in FIG. 2. 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 of the groove | channel and through-hole which are shown to (a). FIG. 7 is a timing chart showing the operation of the control unit shown in FIG. FIG. 3 is a second diagram illustrating a configuration of the image forming unit illustrated in FIG. 1. FIG. 4 is a third diagram illustrating a configuration of the image forming unit illustrated in FIG. 1. It is a figure which shows the structure of the electric charge provision part shown in FIG. FIG. 4 is a fourth diagram illustrating a configuration of the image forming unit illustrated in FIG. 1. FIG. 10 is a fifth diagram illustrating a configuration of the image forming unit illustrated in FIG. 1.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 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 conveying unit 4 disposed on the right side in FIG. 1, a sheet discharging unit 5 disposed on the other side of the image forming unit 3 (left side in FIG. 1), and a control unit 6 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 recording head 34. An image is formed on the paper P conveyed by the belt 32. 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.

  The control unit 6 controls the operation of the ink jet recording apparatus 1. The control unit 6 includes a CPU (Central Processing Unit) and a memory. The memory stores a computer program executed by the CPU, such as firmware. The function of the control unit 6 is realized by the CPU executing the computer program stored in the memory.

  Next, the image forming unit 3 will be described with reference to FIG. FIG. 2 is a first diagram illustrating a configuration of the image forming unit 3 illustrated in FIG. 1. The configuration of the image forming unit 3 is not limited to the configuration shown in FIG. Other configuration examples of the image forming unit 3 will be described later with reference to FIGS.

  As illustrated in FIG. 2, the image forming unit 3 includes a conveyance unit 31, a negative pressure application unit 33, a recording head 34, a plate-like member 35, and a first voltage application unit 381. 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, an adsorption roller 312, a drive roller 313, a tension roller 314, a pair of guide rollers 315, liquid absorption A roller 316 and a conveyor belt 32 are 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 through a plurality of suction holes 321 (see FIG. 4) formed in 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 upstream of the plate-like member 35 in the transport direction of the paper P. The suction roller 312 presses the sheet P against the upper surface of the transport belt 32 (which is a surface on which the sheet P is placed, and may be simply referred to as “mounting surface” hereinafter) and moves downstream in the sheet P transport direction. Send paper P. At least the outer peripheral surface of the suction roller 312 is formed of a conductive material, for example, conductive fluororubber. 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 liquid absorption roller 316 is used for cleaning the transport belt 32 in a process of cleaning the inside of the inkjet recording apparatus 1 (hereinafter referred to as “cleaning process”). The liquid absorption roller 316 is formed of a material, for example, a sponge, whose outer peripheral surface sucks ink. The liquid absorption roller 316 is moved to a position where the outer peripheral surface thereof contacts the conveyance belt 32 during the cleaning process. The liquid absorption roller 316 rotates while contacting the conveyance belt 32, thereby sucking ink attached to the conveyance belt 32 and removing ink on the conveyance belt 32.

  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. The guide member 332 is grounded. In FIG. 2, the illustration of the groove 334 (see FIG. 3, FIG. 4, etc.) is omitted, but in this embodiment, the through hole 335 is the bottom surface of the groove 334 formed on the upper surface of the guide member 332. To the guide member 332.

  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 forms a space (hereinafter referred to as “negative pressure generation space”) 3311 in which a negative pressure for sucking the paper P toward the transport belt 32 is generated. In the present embodiment, the air circulation chamber 331 is formed by a bottomed cylindrical box-shaped member having an open upper surface. The upper surface of the side wall constituting the air circulation chamber 331 is fixed to the guide member 332. The opening on the upper surface of the air circulation chamber 331 is covered with a guide member 332. That is, in this embodiment, the guide member 332 becomes the upper wall of the air circulation chamber 331.

  The negative pressure generator 336 is a device that generates a negative pressure in the air circulation chamber 331, and is, for example, a fan or a vacuum pump. The negative pressure generating unit 336 is disposed below the air circulation chamber 331, specifically on the bottom surface 3312 of the air circulation chamber 331. The negative pressure generator 336 generates negative pressure in the air circulation chamber 331 by discharging the air in the air circulation chamber 331 to the outside of the air circulation chamber 331 through the exhaust port 337. Due to the negative pressure generated in the air circulation chamber 331, the paper P is sucked toward the transport belt 32 through the suction hole 321 (see FIG. 4) of the transport belt 32 and the through hole 335 of the guide member 332. Is adsorbed to the conveyor belt 32. Accordingly, the transport unit 31 can transport the paper P while adsorbing the paper P to the transport belt 32.

  The plate-like member 35 is disposed on the upstream side (the right side in FIG. 2) in the transport direction of the paper P with respect to the recording head 34. In other words, the plate-like member 35 is disposed between the recording head 34 a and the suction roller 312. The plate-like member 35 corresponds to a part of the “space forming part”. A space between the plate-like member 35 and the mounting surface (guide member 332) 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.

  Next, a configuration in the vicinity of the plate-like member 35 will be described with reference to FIG. FIG. 3 is a diagram showing a configuration in the vicinity of the plate-like member 35 shown in FIG.

  As shown in FIG. 3, the plate member 35 is fixed to the head base 37. The head base 37 is a plate-like member that fixes the recording head 34. In the narrow space 35a, the velocity of the airflow flowing into the narrow space 35a from the space around the narrow space 35a is larger after flowing into the narrow space 35a than before flowing into the narrow space 35a. Thus, the distance H is set. Here, the distance H is a distance in a direction orthogonal to the upper surface (mounting surface) of the conveyance belt 32 in the narrow space 35a, in other words, a length (distance) in the vertical direction of the narrow space 35a. Specifically, the lower surface of the plate-like member 35 forms a narrow space 35a between the upper surface of the transport belt 32 and the distance H set to a preset threshold distance HS (for example, 3 mm) or less. . In the present embodiment, the distance H is 2 mm, for example.

  The plate-like member 35 is a conductive portion 352 that is entirely or partially conductive. In the example shown in FIGS. 2 and 3, the side facing the mounting surface of the plate member 35, that is, the lower surface of the plate member 35 is the conductive portion 352. The conductive portion 352 is formed of a conductive material, for example, a metal such as stainless steel.

  In the above description with reference to FIG. 3, the case where the thickness of the paper P is sufficiently thin compared to the distance H has been described, but the distance H may be changed according to the thickness of the paper P. Specifically, for example, the plate member 35 is moved up and down according 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 member 35 is substantially constant (for example, 2 mm). May be.

  The head base 37 has a narrow space 35a on the downstream side in the transport direction of the paper P with respect to the plate-like member 35 (left side in FIG. 3) and on the upstream side in the transport direction of the paper P (right side in FIG. 3). Holes 371 and 372 for allowing air to flow into are formed. The holes 371 and 372 are long holes extending in the width direction of the paper P (in FIG. 3, the direction perpendicular to the paper surface).

  In the present embodiment, the case where the holes formed in the head base 37 are the holes 371 and 372 extending in the width direction of the paper P has been described, but the holes formed in the head base 37 have other shapes. The form which is. For example, the hole formed in the head base 37 may be a substantially cylindrical hole formed in a plurality along the width direction of the paper P.

  The air flowing into the narrow space 35a from the holes 371 and 372 formed in the head base 37 passes through the plurality of suction holes 321 formed in the transport belt 32 and the plurality of through holes 335 formed in the guide member 332. Through the air flow chamber 331. In other words, the air circulation chamber 331 is in a negative pressure state (for example, the pressure difference from the atmospheric pressure is about 0.005 atm ≈ about 500 Pa) by the negative pressure generation unit 336, so Air flows from the narrow space 35 a through the plurality of suction holes 321 formed in the transport belt 32 and the plurality of through holes 335 formed in the guide member 332. Further, since air flows into the air circulation chamber 331 from the narrow space 35a, air flows into the narrow space 35a from the holes 371 and 372 formed in the head base 37.

  As described above, air flows along the arrows FD1 and FD2 shown in FIG. Since the distance H is set to be equal to or less than the preset threshold distance HS, the wind speed in the narrow space 35a increases. The wind speed in the narrow space 35a is preferably 6.0 m / second or more, for example.

  As described above, the wind indicated by the arrow FD1 blows from the upstream side to the downstream side in the conveyance direction of the paper P in the narrow space 35a (to the left in FIG. 3). The paper dust PD adhering to the front end (left end in FIG. 3) of the paper P can be removed, and the paper dust PD removed in the air circulation chamber 331 can be collected. Further, since the wind indicated by the arrow FD2 blows from the downstream side in the conveyance direction of the paper P toward the upstream side (in the right direction in FIG. 3) in the narrow gap space 35a, as shown in FIG. The paper dust PD adhering to the rear end (right end in FIG. 3) can be removed, and the paper dust PD removed in the air circulation chamber 331 can be collected. Therefore, the paper dust adhering to the paper P can be effectively removed.

  Furthermore, as described above, since the plate-like member 35 is fixed to the head base 37, the plate-like member 35 can be easily arranged. Further, since holes 371 and 372 for allowing air to flow into the narrow space 35a are formed in the head base 37, the air can smoothly flow into the narrow space 35a.

  In the present embodiment, the case where the plate-like member 35 is fixed to the head base 37 is described, but the plate-like member 35 may be fixed to the apparatus housing 100 shown in FIG. For example, the fixing member extending from the apparatus housing 100 may fix both ends of the plate-like member 35 in the width direction (the direction perpendicular to the paper surface in FIG. 3). In this case, since there is no member that obstructs the flow of air flowing from the downstream side and the upstream side in the conveyance direction of the paper P in the narrow space 35a, the wind speed in the narrow space 35a can be further increased. Therefore, paper dust can be more effectively removed.

  Further, as shown in FIG. 3, a taper 351 is formed on the plate-like member 35 so that the distance H increases as it approaches the end surface of the plate-like member 35 in the conveyance direction of paper P (left and right in FIG. 3). Has been. The right taper 351 in FIG. 3 is formed such that the distance H increases as it approaches the upstream end surface of the sheet-like member 35 in the conveyance direction of paper P (left-right direction in FIG. 3). In addition, the left taper 351 in FIG. 3 is formed such that the distance H increases as it approaches the downstream end face of the sheet-like member 35 in the conveyance direction of paper P (left-right direction in FIG. 3). In other words, the plate-like member 35 approaches the end face of the plate-like member 35 in the transport direction of the paper P toward the upstream end and the downstream end of the paper P in the transport direction of the paper P, respectively. A taper 351 is formed so that the thickness of the plate-like member 35 is reduced.

  As described above, the taper 351 is formed on the plate-like member 35 such that the distance H increases as it approaches the end surface of the plate-like member 35 in the conveyance direction of paper P (the left-right direction in FIG. 3). The pressure loss of the air flowing along the plate member 35 can be reduced. Therefore, since the wind speed in the narrow space 35a can be increased, paper dust can be more effectively removed.

  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.

  Here, 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 row of oval grooves 334 extending in the conveyance direction of the paper P (left and right in FIG. 5), in the width direction of the guide member 332 (up and down in FIG. 5). In the direction). In addition, a through hole 335 that penetrates the guide member 332 in the thickness direction is formed at a substantially central position in the groove 334 in the conveyance direction of the paper P (the left-right direction in FIG. 5). The cross section of the through hole 335 is circular.

  The broken line shown in FIG. 5 indicates the position of the plate member 35 projected onto the guide member 332. With respect to the projection image of the plate-like member 35 on the guide member 332, the through holes 335 are respectively provided on the upstream side (left side in FIG. 5) of the paper P and the downstream side (right side in FIG. 5) of the paper P. Are formed one by one. 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 35 (left side in FIG. 5). It extends further upstream in the transport direction of the paper P than the end position. 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 the downstream side in the transport direction of the paper P in the projection image of the plate-like member 35 (right side in FIG. 5). ) It extends further downstream in the transport direction of the paper P than the edge position.

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

  As shown in FIG. 6A, a through hole that penetrates the guide member 332 in the thickness direction at a substantially central position in the conveyance direction of paper P in the groove 334 (left-right direction in FIG. 6A). 335 is formed. 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. Further, a taper 335a and a taper 335b are formed at the upper end and the lower end of the through hole 335, respectively.

  As described above, since the groove 334 is formed at a position facing the plate-like member 35, the negative pressure applied from the air circulation chamber 331 through the through hole 335 is applied to the region where the groove 334 is formed. Also works. Therefore, since air becomes easier to flow along the arrows FD1 and FD2 shown in FIG. 3, paper dust can be more effectively removed.

  Further, as described above, since the taper 335a and the taper 335b are formed at the upper end and the lower end of the through hole 335, respectively, the pressure loss of the air flowing through the through hole 335 can be reduced. Therefore, since air becomes easier to flow along the arrows FD1 and FD2 shown in FIG. 3, paper dust can be more effectively removed.

  Returning to FIG. 4, the positional relationship between the suction holes 321 formed in the conveyance belt 32 and the grooves 334 formed in the guide member 332 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, 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 that is set to a negative pressure by the negative pressure generator 336 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.

  Refer to FIG. 2 again. The first voltage application unit 381 applies a voltage having the first polarity to the conductive unit 352 of the plate-like member 35 under the control of the control unit 6. Here, the first polarity is the same polarity as the polarity in which at least a part (specifically, the nozzle) of the recording head 34 is charged, and is the negative electrode in this embodiment. The nozzles of the recording head 34 are charged to the first polarity by, for example, ejecting ink. For example, the first voltage application unit 381 applies a voltage of −1.0 kV to the conductive unit 352 of the plate-like member 35.

  As described above, the ink jet recording apparatus 1 applies the voltage of the first polarity to the conductive portion 352 of the plate-like member 35, whereby the second polarity opposite to the first polarity (in this embodiment, the positive electrode). The charged paper dust can be adsorbed to the conductive portion 352 of the plate-like member 35. That is, the ink jet recording apparatus 1 can effectively collect the paper dust charged to the second polarity that easily adheres to the nozzles on the upstream side of the recording head 34 in the transport direction of the paper P. Therefore, the ink jet recording apparatus 1 can reduce the amount of paper dust conveyed to the lower side of the recording head 34 (particularly, the amount of paper dust charged to the second polarity that easily adheres to the nozzle). The adhesion of paper dust to the nozzle can be effectively suppressed.

  In addition, applying the first polarity voltage to the conductive portion 352 of the plate-like member 35 is effective in the following points. That is, as described with reference to FIG. 3, when the leading edge or the trailing edge of the paper P passes below the plate-like member 35, the paper dust attached to the leading edge or the trailing edge of the paper P Then, the air is collected in the air circulation chamber 331 by the wind indicated by the arrow FD1 or the arrow FD2. On the other hand, when the central portion of the sheet P passes below the plate member 35, most of the grooves 334 existing below the plate member 35 are covered with the sheet P. As a result, the amount of air sucked through the through hole 335 existing below the plate-like member 35 (the amount of air sucked per unit time) is lowered, and the wind speed in the narrow space 35a is lowered. Therefore, the paper dust adhering to the central portion of the paper P is hardly collected in the air circulation chamber 331 and is not easily removed from the paper P.

  Therefore, by applying a voltage of the first polarity to the conductive portion 352 of the plate-like member 35, the inkjet recording apparatus 1 causes the paper dust attached to the central portion of the paper P (particularly, the first to be easily attached to the nozzle). 2) can be removed from the paper P by adsorbing the conductive powder 352 of the plate-like member 35 to the conductive portion 352. Note that the ink jet recording apparatus 1 can also remove the paper dust adhering to the leading or trailing edge of the paper P from the paper P by adsorbing it to the conductive portion 352 of the plate-like member 35. Therefore, the ink jet recording apparatus 1 is configured to remove the paper dust adhering to the paper P more than when the first polarity voltage is not applied to the conductive portion 352, that is, when the paper dust is collected only by air suction. It can be effectively removed.

  When there are a plurality of conductive portions 352, the first voltage application unit 381 applies a voltage of the first polarity to some of the plurality of conductive portions 352, and a voltage of the second polarity to some of the other conductive portions 352. Apply. A configuration in the case where there are a plurality of conductive portions 352 will be described later with reference to FIGS. 11 and 12.

  In the present embodiment, the control unit 6 controls the first voltage application unit 381 to apply a voltage to the conductive unit 352 while a predetermined target process is being performed. As shown in FIG. 2, FIG. 8, and FIG. 9, when there is one conductive part 352, the control part 6 applies a first polarity voltage to the conductive part 352. On the other hand, as shown in FIG. 11 and FIG. 12, when there are a plurality of conductive portions 352, the control unit 6 applies a voltage of the first polarity to some of the plurality of conductive portions 352, and sets the others to the first. A voltage of polarity 2 is applied. Here, the target process is a process involving driving of the conveyance belt 32, and is, for example, a process of forming an image on the paper P (hereinafter referred to as “image forming process”) and / or a cleaning process. Hereinafter, the timing at which a voltage is applied to the conductive portion 352 will be specifically described with reference to FIG.

  FIG. 7 is a timing chart showing the operation of the control unit 6 shown in FIG.

  First, the operation of the control unit 6 when an instruction to start the target process is received will be described with reference to FIG.

  When a signal (start signal) for instructing the start of the target process is input to the control unit 6 at time T1, the control unit 6 starts driving the negative pressure generation unit 336 at the subsequent time T3, so that the negative pressure is generated. The pressure application unit 33 starts application of negative pressure. The time interval from time T1 to time T3 is, for example, 100 msec.

  Thereafter, at time T <b> 4, the control unit 6 causes the first voltage application unit 381 to start applying a voltage to the conductive unit 352. The time interval from time T3 to time T4 is, for example, 500 msec.

  Between this time T3 and time T4, paper dust accumulated on the paper placement section of the conveyor belt 32, paper powder floating on the paper placement section, or paper adhered to the plate-like member 35 The powder is sucked into the air circulation chamber 331 and collected. Here, the paper placement section is a section on which the paper P of the transport belt 32 is placed, and the transport belt 32 passes over the guide member 332 from a position where the transport belt 32 contacts the belt speed detection roller 311 and the transport belt 32 reaches the drive roller 313. It is a section to the position where it touches. In addition, since the voltage is not yet applied to the electroconductive part 352 from the time T3 to the time T4, the adhesive force of the paper dust to the plate-shaped member 35 is weakened. Therefore, the paper dust adhering to the plate-like member 35 is easily sucked into the air circulation chamber 331 by the negative pressure applied by the negative pressure application unit 33.

  Thereafter, at time T <b> 5, the control unit 6 starts driving the driving roller 313 and starts driving the transport belt 32. The time interval from time T4 to time T5 is, for example, 1000 msec. Paper dust remaining around the plate-like member 35 between this time T4 and time T5 (paper dust adhering to the plate-like member 35 and paper dust floating around the plate-like member 35) Is firmly adsorbed to the conductive portion 352.

  Thereafter, the control unit 6 performs target processing. Specifically, when the target process is an image forming process, the control unit 6 starts conveyance of the paper P and controls the recording head 34 to form an image on the paper P. When the target process is a cleaning process, the control unit 6 stands by until a predetermined cleaning time (for example, several minutes) elapses with the transport belt 32 being driven. While waiting, the paper dust adhering to the conveyor belt 32 is collected by being sucked into the air circulation chamber 331 or adsorbed by the conductive portion 352.

Thus, in this embodiment, when the control unit 6 receives an instruction to start a target process, the control unit 6 performs the target process after performing the following processes (1) to (3) in this order.
Process (1): The negative pressure application unit 33 is started to apply a negative pressure.
Process (2): The first voltage application unit 381 is started to apply a voltage to the conductive unit 352.
Process (3): Driving of the conveyor belt 32 is started.

  Thus, before the transport belt 32 is driven, paper dust accumulated on the paper placement section of the transport belt 32, paper powder floating on the paper placement section, and the like are sucked into the air circulation chamber 331. Or is attracted to the conductive portion 352 and collected. Therefore, when the inkjet recording apparatus 1 starts to drive the conveyance belt 32, the occurrence of the problem that the paper dust accumulated on the conveyance belt 32 flies in the air and adheres to the nozzle due to the vibration of the conveyance belt 32 is suppressed. be able to.

  Next, the operation of the control unit 6 after the target process is completed will be described with reference to FIG.

  First, the control unit 6 stops driving of the driving roller 313 and stops driving of the conveying belt 32 at time T6 after the target process is completed.

  Thereafter, at time T <b> 7, the control unit 6 causes the first voltage application unit 381 to stop applying the voltage to the conductive unit 352. The time interval from time T6 to time T7 is, for example, 500 msec.

  Thereafter, at time T <b> 8, the control unit 6 stops driving the negative pressure generation unit 336 and causes the negative pressure application unit 33 to stop applying negative pressure. The time interval from time T7 to time T8 is, for example, 500 msec.

As described above, in the present embodiment, the control unit 6 performs the following processes (4) to (6) in this order after the target process is completed.
Process (4): Drive of the conveyor belt 32 is stopped.
Process (5): The first voltage application unit 381 is stopped from applying the voltage to the conductive unit 352.
Process (6): The negative pressure application unit 33 stops application of negative pressure.

  That is, after the target process is completed, the control unit 6 stops driving the conveyance belt 32 before stopping the application of voltage to the conductive unit 352 and the application of negative pressure by the negative pressure application unit 33. As a result, the inkjet recording apparatus 1 is driven by the wind (driving wind) generated with the driving of the conveying belt 32 after the application of the voltage to the conductive portion 352 and the application of the negative pressure by the negative pressure applying portion 33 are stopped. It is possible to suppress the occurrence of the problem that the paper dust is carried to the vicinity of the recording head 34 and adheres to the nozzle.

  FIG. 8 is a second diagram showing the configuration of the image forming unit 3 shown in FIG.

  In the configuration example illustrated in FIG. 8, the image forming unit 3 further includes a second voltage application unit 382 in addition to the components illustrated in FIG. 2. The second voltage application unit 382 applies a voltage of the second polarity (positive electrode in the present embodiment) to the suction roller 312, specifically to the outer peripheral surface of the suction roller 312 under the control of the control unit 6. . For example, the second voltage application unit 382 applies a voltage of +1.5 kV to the suction roller 312.

  Here, as described above, the guide member 332 is grounded. Therefore, when a voltage is applied to the suction roller 312, a current flows from the suction roller 312 to the guide member 332 via the transport belt 32 or the transport belt 32 and the paper P. As a result, the paper P passing between the suction roller 312 and the guide member 332 and the paper dust attached to the paper P are charged.

  In the present embodiment, the control unit 6 controls the second voltage application unit 382 to apply the second polarity voltage to the suction roller 312 while the first polarity voltage is applied to the conductive unit 352. Apply.

  As described above, the inkjet recording apparatus 1 is attached to the paper P passing between the suction roller 312 and the guide member 332 and the paper P by applying the second polarity voltage to the suction roller 312. The paper dust can be charged to the second polarity. Thereby, the ink jet recording apparatus 1 can more effectively adsorb the paper dust adhering to the paper P to the conductive portion 352 of the plate-like member 35 and remove it.

  FIG. 9 is a third diagram showing the configuration of the image forming unit 3 shown in FIG.

  In the configuration example illustrated in FIG. 9, the image forming unit 3 further includes a charge applying unit 39 and a third voltage applying unit 383 in addition to the components illustrated in FIG. 8.

  The charge applying unit 39 is disposed upstream of the recording head 34 in the transport direction of the paper P and downstream of the plate member 35 in the transport direction of the paper P. The charge applying unit 39 applies the charge having the polarity of the applied voltage to the paper P passing under the charge applying unit 39 and the paper dust attached to the paper P. The configuration of the charge applying unit 39 will be described later with reference to FIG.

  The third voltage application unit 383 applies a voltage of the first polarity (negative in this embodiment) to the charge applying unit 39 under the control of the control unit 6. For example, the third voltage application unit 383 applies a voltage of −3.0 kV to the charge application unit 39.

  In the present embodiment, the control unit 6 controls the third voltage application unit 383 while the voltage of the first polarity is applied to the conductive unit 352 and the voltage of the second polarity is applied to the suction roller 312. Then, a voltage having the first polarity is applied to the charge applying unit 39. That is, while the voltage of the first polarity is applied to the conductive portion 352 and the voltage of the second polarity is applied to the suction roller 312, the charge imparting portion 39 has the paper P passing thereunder and the paper P A charge having the first polarity is imparted to the paper dust adhering to the paper.

  As described above, the ink jet recording apparatus 1 has the first effect on the paper P and the paper dust on the upstream side in the transport direction of the paper P with respect to the recording head 34 and on the downstream side in the transport direction of the paper P with respect to the plate member 35. By applying a charge of polarity, the paper P and paper powder charged to the second polarity when passing between the suction roller 312 and the guide member 332 are charged to the first polarity that hardly adheres to the nozzle. Can be made. As a result, the ink jet recording apparatus 1 can suppress the paper powder charged to the second polarity that easily adheres to the nozzles from being conveyed to the lower side of the recording head 34 and adhering to the nozzles.

  FIG. 10 is a diagram illustrating a configuration of the charge applying unit 39 illustrated in FIG. 9. FIG. 10A is a perspective view of the charge applying unit 39. FIG. 10B is an exploded view of the charge applying unit 39.

  As shown in FIG. 10A, the charge applying unit 39 is fixed to the head base 37. Further, as shown in FIG. 10B, the charge applying unit 39 includes a mounting base 391, an electrode 392, and a paper guide 393.

  The attachment base 391 is a base to which the electrode 392 and the paper guide 393 are attached, and is fixed to the head base 37. The paper guide 393 is a member that guides the conveyed paper P below the charge applying unit 39. The mounting base 391 and the paper guide 393 are made of, for example, an insulating resin.

  The electrode 392 is a member that imparts a charge having a first polarity to the paper P and the paper powder PD that pass therebelow. The electrode 392 is a needle electrode, for example, and is made of a metal such as stainless steel. The electrode 392 is sandwiched between the mounting base 391 and the paper guide 393. When a voltage having the first polarity is applied to the electrode 392 by the third voltage application unit 383, a discharge occurs between the electrode 392 and the guide member 332. As a result, the charge having the first polarity is applied to the paper P and the paper powder PD that pass under the electrode 392.

  FIG. 11 is a fourth diagram showing the configuration of the image forming unit 3 shown in FIG.

  In the configuration example shown in FIG. 11, the plate-like member 35 has a plurality of conductive portions 352 (two in this embodiment). The plurality of conductive portions 352 are arranged side by side along the conveyance direction of the paper P at a predetermined interval.

  An interval between two adjacent conductive portions 352 among the plurality of conductive portions 352 is set to an interval at which no electrical interference occurs when a voltage is applied to the two conductive portions 352. Further, the length of the conductive portion 352 in the conveyance direction of the paper P (hereinafter simply referred to as “the length of the conductive portion 352”) may be the same among the plurality of conductive portions 352 or may be different. For example, the length of each conductive portion 352 may be determined based on the charging characteristics of the paper powder that is attached to the paper P and conveyed to the lower side of the plate-like member 35. For example, when most of the paper dust that has been adhered and conveyed to the paper P is charged to the second polarity, the length of the conductive portion 352 to which the voltage of the first polarity is applied is It may be set longer than the length of the conductive portion 352 to which a voltage having a polarity of 2 is applied.

  The first voltage application unit 381 controls the plurality of conductive elements so that the polarities of the voltages applied to two adjacent conductive units 352 out of the plurality of conductive units 352 are different polarities under the control of the control unit 6. A voltage is applied to each of the units 352. More preferably, the first voltage application unit 381 has a first polarity voltage applied to the conductive unit 352 located on the most upstream side (the rightmost side in FIG. 11) of the plurality of conductive units 352 in the transport direction of the paper P. Apply. For example, in the example of FIG. 11, the first voltage application unit 381 applies a voltage of the first polarity to the conductive unit 352 located on the right side, and applies a voltage of the second polarity to the conductive unit 352 located on the left side. Apply.

  The control method of the first voltage application unit 381 by the control unit 6 is as described with reference to FIGS. That is, the control unit 6 controls the first voltage application unit 381 while the target process is being performed, so that the voltage (the voltage of the first polarity or the second polarity) is applied to each of the plurality of conductive units 352. Is applied.

  Specifically, when receiving an instruction to start the target process, the control unit 6 performs the target process after performing the above-described processes (1) to (3) in this order. Here, in the configuration example illustrated in FIG. 11, the control unit 6 causes the first voltage application unit 381 to start applying a voltage to each of the plurality of conductive units 352 in the process (2). In addition, after the target process ends, the control unit 6 performs the above-described processes (4) to (6) in this order. Here, in the configuration example illustrated in FIG. 11, the control unit 6 causes the first voltage application unit 381 to stop applying the voltage to each of the plurality of conductive units 352 in the process (5).

  As described above, the ink jet recording apparatus 1 applies the voltages having different polarities (first polarity or second polarity) to the plurality of conductive portions 352, so that the second polarity that easily adheres to the nozzle (this embodiment). In this case, not only paper powder charged to the positive electrode) but also paper powder charged to the first polarity (negative electrode in the present embodiment) can be adsorbed to the conductive portion 352 of the plate-like member 35. That is, the ink jet recording apparatus 1 can effectively collect paper dust charged to either the first polarity or the second polarity upstream of the recording head 34 in the transport direction of the paper P. it can. Therefore, the ink jet recording apparatus 1 can reduce the amount of paper dust conveyed below the recording head 34, and can effectively suppress the adhesion of paper dust to the nozzle.

  FIG. 12 is a fifth diagram showing the configuration of the image forming unit 3 shown in FIG.

  In the configuration example illustrated in FIG. 12, the image forming unit 3 includes a plurality of plate members 35 (two in the present embodiment). The plurality of plate-like members 35 are arranged side by side along the conveyance direction of the paper P at a predetermined interval. In the configuration example shown in FIG. 12, the entire plate-like member 35 is a conductive portion 352.

  The interval between two adjacent plate members 35 among the plurality of plate members 35 is such that no electrical interference occurs when a voltage is applied to the two plate members 35 (conductive portions 352). Is set. Further, the length of the plate-shaped member 35 in the conveyance direction of the paper P (hereinafter simply referred to as “the length of the plate-shaped member 35”) may be the same among the plurality of plate-shaped members 35 or different. Also good. For example, the length of each plate-like member 35 may be determined based on the charging characteristics of the paper powder that has been attached to the paper P and conveyed to the lower side of the plate-like member 35. For example, when most of the paper dust that has been conveyed while adhering to the paper P is charged to the second polarity, the length of the plate-like member 35 to which the voltage of the first polarity is applied is It may be set longer than the length of the plate-like member 35 to which the voltage of the second polarity is applied.

  The first voltage application unit 381 has a plurality of polarities so that the polarities of the voltages applied to two adjacent plate-like members 35 among the plurality of plate-like members 35 are different from each other under the control of the control unit 6. A voltage is applied to each of the plate-like members 35. More preferably, the first voltage application unit 381 has the first polarity on the plate-like member 35 located on the most upstream side (the rightmost side in FIG. 12) in the transport direction of the paper P among the plurality of plate-like members 35. Apply a voltage of. For example, in the example of FIG. 12, the first voltage application unit 381 applies a first polarity voltage to the plate-like member 35 located on the right side and applies a second polarity to the plate-like member 35 located on the left side. Apply voltage.

  The control method of the first voltage application unit 381 by the control unit 6 is as described with reference to FIGS. That is, the control unit 6 controls the first voltage application unit 381 while the target process is being performed, so that each of the plurality of plate-like members 35 has a voltage (a voltage having a first polarity or a second polarity). ) Is applied.

  Specifically, when receiving an instruction to start the target process, the control unit 6 performs the target process after performing the above-described processes (1) to (3) in this order. Here, in the configuration example illustrated in FIG. 12, the control unit 6 causes the first voltage application unit 381 to start applying a voltage to each of the plurality of plate-like members 35 in the process (2). In addition, after the target process ends, the control unit 6 performs the above-described processes (4) to (6) in this order. Here, in the configuration example illustrated in FIG. 12, the control unit 6 causes the first voltage application unit 381 to stop applying the voltage to each of the plurality of plate-like members 35 in the process (5).

  As described above, the ink jet recording apparatus 1 applies the voltages having different polarities (first polarity or second polarity) to the plurality of plate-like members 35, so that the first polarity (negative electrode in the present embodiment) is applied. The charged paper dust can be adsorbed to the plate-like member 35 to which the voltage of the second polarity is applied, and the paper dust charged to the second polarity (positive electrode in the present embodiment) It can be adsorbed to the plate-like member 35 to which a polar voltage is applied. That is, the ink jet recording apparatus 1 can effectively collect paper dust charged to either the first polarity or the second polarity upstream of the recording head 34 in the transport direction of the paper P. it can. Therefore, the ink jet recording apparatus 1 can reduce the amount of paper dust conveyed below the recording head 34, and can effectively suppress the adhesion of paper dust to the nozzle.

  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 configuration example shown in FIG. 9, the image forming unit 3 includes the charge applying unit 39, the second voltage applying unit 382, and the third voltage applying unit 383, but the second voltage application is not necessarily performed. The portion 382 may not be provided. That is, the control unit 6 causes the charge applying unit 39 to apply the first polarity voltage without applying the voltage to the suction roller 312 while the voltage of the first polarity is applied to the conductive unit 352. It may be.

  (2) In the configuration example shown in FIG. 12, the plate-like member 35 is entirely the conductive portion 352, but a part thereof may be the conductive portion 352. In this case, the polarity of the voltage applied to the respective conductive portions 352 of the two adjacent plate-like members 35 among the plurality of plate-like members 35 is controlled by the first voltage application portion 381. A voltage is applied to each of the conductive portions 352 of the plurality of plate-like members 35 so as to have different polarities.

  (3) In this embodiment, the case where the conveyance belt 32 conveys the paper P in the image forming unit 3 has been described. However, the image forming unit 3 may convey 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.

  (4) In the present embodiment, the case where the narrow space 35a is formed by the plate-like member 35 has been described. However, the narrow space 35a may be formed by other methods. For example, the head base 37 may be formed so as to protrude toward the transport belt 32 on the upstream side in the transport direction of the paper P with respect to the recording head 34 to form the narrow space 35a. In this case, the structure can be simplified.

  Further, instead of the plate-like member 35, the narrow space 35a may be formed by a belt stretched around two rollers. 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, A narrow gap space 35 a is 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.

  (5) Although the case where the guide member 332 and the air circulation chamber 331 are separate members has been described in the present embodiment, the guide member 332 and the air circulation chamber 331 may be integrally formed. In this case, leak 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 and the air circulation chamber 331) can be prevented.

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

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 2 Paper feeding part 3 Image forming part 31 Conveying part 312 Adsorption roller 32 Conveying belt 321 Suction hole 33 Negative pressure application part 331 Air circulation chamber 332 Guide member (conveying plate)
334 Groove 335 Through-hole 335a, 335b Taper 336 Negative pressure generating part 34 (34a, 34b, 34c, 34d) Recording head 35 Plate member (space forming part)
351 Taper 352 Conductive part 35a Narrow space 36 Transport guide 37 Head base (space forming part)
371, 372 Hole 381 First voltage application unit 382 Second voltage application unit 383 Third voltage application unit 39 Charge application unit 6 Control unit

Claims (13)

A control unit;
A transport unit that transports the recording medium placed on the mounting surface of the recording medium;
A recording head that forms an image by ejecting ink onto the recording medium conveyed by the conveying unit;
A negative pressure applying unit that applies a negative pressure through a plurality of holes formed in the mounting surface and adsorbs the recording medium transported by the transport unit to the mounting surface;
Forming a narrow space between the recording head and the placement surface upstream of the recording head in the transport direction of the recording medium, and a space forming portion in which all or part of the space is a conductive portion;
A first voltage application unit that applies a voltage to the conductive unit;
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. The distance in the direction perpendicular to the mounting surface is set as described above,
The control unit is an ink jet recording apparatus that controls the first voltage application unit to apply a voltage to the conductive unit while a predetermined process is being performed. The transport unit includes a transport belt, and transports the recording medium on the top surface of the transport belt, which is the placement surface,
The predetermined process is a process involving driving of the conveyor belt,
When the control unit receives an instruction to start the predetermined process, the control unit performs the predetermined process after performing the following (1) to (3) in the order.
(1) causing the negative pressure application unit to start applying negative pressure;
(2) causing the first voltage application unit to start applying a voltage to the conductive unit;
(3) Start driving the conveyor belt;
The ink jet recording apparatus according to claim 1. The control unit performs the following (4) to (6) in the order after the predetermined processing is completed.
(4) Stop driving the conveyor belt;
(5) causing the first voltage application unit to stop applying the voltage to the conductive unit;
(6) Stop application of negative pressure to the negative pressure application unit,
The ink jet recording apparatus according to claim 2.   The inkjet recording apparatus according to claim 2, wherein the predetermined process is an image forming process for forming an image on the recording medium and / or a cleaning process for cleaning the inside of the inkjet recording apparatus. The recording head discharges ink so that at least a part thereof is charged to the first polarity,
5. The inkjet recording apparatus according to claim 1, wherein the first voltage application unit applies a voltage having the first polarity to the conductive unit. 6. On the upstream side in the transport direction from the space forming portion, an adsorption roller that presses the recording medium against the placement surface and sends the recording medium to the downstream side in the transport direction;
A second voltage application unit that applies a voltage having a second polarity opposite to the first polarity to the suction roller;
The control unit controls the second voltage application unit to apply the second polarity voltage to the suction roller while the voltage of the first polarity is applied to the conductive unit. The ink jet recording apparatus according to claim 5. On the upstream side in the transport direction with respect to the recording head and on the downstream side in the transport direction with respect to the space forming portion, the charge having the polarity of the applied voltage is applied to the recording medium and the paper dust attached to the recording medium. A charge imparting portion to impart,
A third voltage applying unit that applies a voltage of the first polarity to the charge applying unit;
The control unit controls the third voltage application unit to apply the first polarity voltage to the charge applying unit while the voltage of the first polarity is applied to the conductive unit. An ink jet recording apparatus according to claim 5 or 6. The space forming portion includes a plurality of the conductive portions,
The plurality of conductive portions are arranged side by side along the transport direction at a predetermined interval,
The first voltage application unit applies a voltage to each of the plurality of conductive parts such that polarities of voltages applied to two adjacent conductive parts among the plurality of conductive parts have different polarities. The inkjet recording apparatus according to any one of claims 1 to 4. A plurality of the space forming portions;
The plurality of space forming portions are arranged side by side along the transport direction at a predetermined interval,
The first voltage application unit has the plurality of spaces such that polarities of voltages applied to the conductive portions of the two adjacent space formation units among the plurality of space formation units are different from each other. The ink jet recording apparatus according to claim 1, wherein a voltage is applied to each conductive portion of the forming portion.   The said space formation part forms the said narrow space so that the distance of the direction orthogonal to the said mounting surface in the said narrow space may become below a predetermined threshold distance. 2. An ink jet recording apparatus according to item 1.   The said space formation part is a plate-shaped member which opposes the mounting surface of the said recording medium in the said conveyance part, and has a plane substantially parallel to the mounting surface of the said recording medium. 2. An ink jet recording apparatus according to item 1. A head base for supporting the recording head;
The plate-like member is fixed to the head base,
The head base is formed with holes through which air flows into the narrow gap space on the upstream side in the conveyance direction of the recording medium and on the downstream side in the conveyance direction of the recording medium with respect to the plate-like member. 11. An ink jet recording apparatus according to item 11.   The plate-like member is tapered so that the distance in the direction perpendicular to the mounting surface in the narrow gap space increases as it approaches the end surface of the plate-like member in the conveyance direction of the recording medium. An ink jet recording apparatus according to claim 11 or claim 12.

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