Medium conveying device and recording device

Abstract

To enable a backup plate supporting a conveying belt to be easily electrified, by arranging needle electrodes at position of suction holes as well, which can solve the problem that when the needle electrode for electrifying a paper and paper powder is at a position where the electrode can avoid suction holes of a conveying belt, the paper powder cannot be electrified between the two suction holes in a conveying direction, so that the paper powder cannot be removed.SOLUTION: An electrification applying part that electrifies a medium has a rotary part that is rotationally driven by a driving source. The rotary part has needle electrodes and no-electrode parts that are sites on which the needle electrodes are not provided. Positions in a width direction of the plurality of needle electrodes arranged along the width direction are at positions of suction holes and positions in the width direction of the no-electrode parts are at the positions of the suction holes. The needle electrodes are opposed to a region between the two suction holes positioned along a conveying direction in a conveying belt, accompanying rotation of the conveying belt and the rotary part, The no-electrode parts are opposed to the suction holes, accompanying the rotation of the conveying belt and the rotary part.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a medium transport device that transports a medium, and a recording device that includes the medium transport device. [Background technology]

[0002] The inkjet recording device described in Patent Document 1 includes a conveyor belt, needle electrodes, and a plate-like member. The conveyor belt conveys paper while sucking it through suction holes. The needle electrodes apply a voltage to the paper. The plate-like member is disposed between the recording head and the electrode, and a voltage of the opposite polarity to that of the needle electrodes is applied to the plate-like member. Paper dust that has been negatively charged by the needle electrodes is attracted to the plate-like member that has been positively charged, thereby removing the paper dust from the paper.

[0003] In the inkjet recording device described in Patent Document 1, the needle electrode is positioned opposite the center of the adjacent suction holes, i.e., positioned to avoid the suction holes. Since paper dust is sucked in by the suction holes at the positions of the suction holes, it is said that by positioning the needle electrode opposite the center of the adjacent suction holes, paper dust can be effectively removed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-129983 Summary of the Invention [Problem to be solved by the invention]

[0005] In the inkjet recording device described in Patent Document 1, the needle electrodes are positioned to avoid the suction holes, but with this configuration, the paper dust is not charged between the two suction holes in the transport direction. Furthermore, the paper dust is not sucked by the suction holes between the two suction holes in the transport direction, so the paper dust is not removed by either electrostatic adsorption or suction between the two suction holes in the transport direction. To solve this problem, it is preferable to place needle electrodes at the suction holes as well. However, if needle electrodes are also placed at the suction holes, the backup plate supporting the conveyor belt is more likely to become charged when the suction holes and the needle electrodes face each other. If the backup plate becomes charged, this could adversely affect the ink jetting. Furthermore, when paper dust is sucked through the suction holes as in the configuration described in Patent Document 1, the backup plate and the paper dust are charged to the same polarity, which could adversely affect the paper dust suction performance. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, a medium transport device of the present invention includes a transport belt that transports a medium by rotating while attracting the medium via a plurality of suction holes, a support unit that supports the transport belt, a charge applying unit that charges the medium transported by the transport belt, and a charging unit that is provided downstream of the charge applying unit in the transport direction of the medium, and that charges the medium to a polarity opposite to the polarity of the medium charged by the charge applying unit, wherein the charge applying unit is a rotating unit having a rotation axis that is along a width direction that is a direction intersecting the transport direction, and the rotating unit is rotated by a drive source, and a plurality of the rotating units are arranged around the rotation axis, and further The electrode-free section has a plurality of needle electrodes arranged along the width direction and electrode-free sections that are areas where the needle electrodes are not provided, and the electrode-free sections are arranged in plurality along the width direction, wherein the positions in the width direction of the needle electrodes arranged in plurality along the width direction are at the positions of the suction holes, and the positions in the width direction of the electrode-free sections arranged in plurality along the width direction are at the positions of the suction holes, and the needle electrodes face the area between the two suction holes located in the conveying direction on the conveying belt as the conveying belt and the rotating section rotate, and the electrode-free sections face the suction holes as the conveying belt and the rotating section rotate.

[0007] The recording apparatus of the present invention is characterized by including the medium transport device, and a recording unit that is located downstream of the charging unit in the transport direction and performs recording on the medium. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram showing a media transport path of the printer. [Figure 2] FIG. 2 is a block diagram showing the control system of the printer. [Figure 3] FIG. 2 is a side view of a belt unit, a line head, a charge applying unit, and a charging unit. [Figure 4] FIG. 10 is a side view showing the positional relationship between the needle electrodes and electrode-free portions and the suction holes of the conveyor belt. [Figure 5] FIG. 10 is a plan view showing the positional relationship between the needle electrodes and electrode-free portions and the suction holes of the conveyor belt. [Figure 6] FIG. 2 is a side view of a belt unit, a line head, a charge applying unit, and a charging unit. [Figure 7] FIG. 10 is a plan view showing the positional relationship between the needle electrodes and electrode-free portions and the suction holes of the conveyor belt. [Figure 8] FIG. 2 is a side view of a belt unit, a line head, a charge applying unit, and a charging unit. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention will be briefly described below. A medium transport device according to a first aspect includes a transport belt that transports a medium by rotating while attracting the medium via a plurality of suction holes, a support unit that supports the transport belt, a charge applying unit that charges the medium transported by the transport belt, and a charging unit that is provided downstream of the charge applying unit in a transport direction of the medium and charges the medium to a polarity opposite to the polarity of the medium charged by the charge applying unit, wherein the charge applying unit is a rotating unit having a rotation axis along a width direction that is a direction intersecting the transport direction, and the rotating unit is rotated by a drive source, and a plurality of the rotating units are arranged around the rotation axis and further arranged in the width direction. and electrode-free sections which are areas where the needle electrodes are not provided, the electrode-free sections being arranged in plurality along the width direction, wherein the positions in the width direction of the needle electrodes arranged in plurality along the width direction are at the positions of the suction holes, and the positions in the width direction of the electrode-free sections arranged in plurality along the width direction are at the positions of the suction holes, the needle electrodes face an area between two of the suction holes in the conveying belt along the conveying direction as the conveying belt and the rotating section rotate, and the electrode-free sections face the suction holes as the conveying belt and the rotating section rotate.

[0010] According to this aspect, as the conveyor belt and the rotating part rotate, the needle electrodes face the area between the two suction holes in the conveyor belt along the conveyance direction, so that paper dust adhering to the medium can be charged even between the two suction holes in the conveyance direction, thereby making it possible to remove paper dust located between the two suction holes in the conveyance direction. Furthermore, since the electrode-free portion faces the suction hole as the conveying belt and the rotating portion rotate, the support portion can be prevented from becoming charged by the needle electrode, thereby preventing problems associated with the support portion becoming charged.

[0011] A second aspect is an aspect dependent on the first aspect, characterized in that the rotation direction of the rotating portion is opposite to the rotation direction of the conveyor belt. According to this aspect, the rotation direction of the rotating part is opposite to the rotation direction of the conveyor belt, so when the needle electrodes face the medium, the needle electrodes move together with the medium in the conveyance direction, which prevents damage to the medium even if the medium comes into contact with the needle electrodes and also prevents jams from occurring.

[0012] A third aspect is a dependent aspect of the first aspect, characterized in that the plurality of suction holes are arranged in a staggered pattern on the conveying belt, and the electrode-free portion is arranged in a position that can face the plurality of suction holes arranged in the staggered pattern.

[0013] According to this aspect, the electrode-free portion is positioned in a position that can face the plurality of suction holes arranged in a staggered pattern. Therefore, even if the suction holes are arranged in a staggered pattern, the support portion can be prevented from becoming charged by the needle electrode, and problems associated with the support portion becoming charged can be prevented. It should be noted that this aspect is not limited to the first aspect, but may be subordinate to the second aspect.

[0014] A fourth aspect is an aspect dependent on the first aspect, and is characterized in that it includes a first drive source that drives the rotating portion to rotate, a second drive source that drives the conveying belt to rotate, a first rotation detection unit that detects the rotation of the rotating portion, a second rotation detection unit that detects the rotation of the conveying belt, a first reference detection unit that detects a reference position of the rotation of the rotating portion, a second reference detection unit that detects a reference position of the rotation of the conveying belt, and a control unit that controls the first drive source and the second drive source based on detection information from the first rotation detection unit, the second rotation detection unit, the first reference detection unit, and the second reference detection unit so that the suction hole and the electrodeless portion face each other.

[0015] According to this aspect, the control unit can reliably cause the suction hole and the electrode-free portion to face each other. It should be noted that this aspect is not limited to the first aspect, but may be subordinate to the second or third aspect.

[0016] The fifth aspect is a dependent aspect of the first aspect, characterized in that the driving source also serves as the driving source for the conveying belt, and is provided with a power transmission mechanism that synchronizes the rotation of the conveying belt with the rotation of the rotating portion so that the suction holes and the electrode-free portion face each other.

[0017] According to this aspect, the drive source also serves as the drive source for the conveyor belt, thereby suppressing increases in the cost of the device. Furthermore, the device includes a power transmission mechanism that synchronizes the rotation of the conveyor belt with the rotation of the rotating unit so that the suction holes and the electrode-free portions face each other, thereby ensuring that the suction holes and the electrode-free portions face each other. It should be noted that this aspect is not limited to the first aspect, but may be subordinate to the second or third aspect.

[0018] The sixth aspect is a dependent aspect of the first aspect, characterized in that the needle electrode is a first needle electrode, the rotating part is provided with a plurality of second needle electrodes arranged around the rotation axis, and the position of the second needle electrodes in the width direction is in a position that avoids the suction hole.

[0019] According to this aspect, the second needle electrode can charge paper dust adhering to the medium even in areas in the width direction where there are no suction holes, thereby making it possible to more reliably remove paper dust. It should be noted that this aspect is not limited to the first aspect, but may be subordinate to any of the second to fifth aspects.

[0020] A seventh aspect is an aspect dependent on the first aspect, characterized in that an insulating member surrounding the rotating part is provided. According to this aspect, since the insulating member surrounding the rotating part is provided, it is possible to prevent the charge applying part from charging other parts and causing adverse effects. It should be noted that this aspect is not limited to the first aspect, but may be subordinate to any of the second to sixth aspects.

[0021] The recording device of the eighth aspect is characterized by comprising the medium conveying device of any of the first to seventh aspects, and a recording unit located downstream of the charging unit in the conveying direction and performing recording on the medium. According to this aspect, the recording device can achieve the effects of any one of the first to seventh aspects described above.

[0022] A ninth aspect is an aspect dependent on the eighth aspect, characterized in that the charge applying unit charges the medium to the same polarity as the recording unit. According to this aspect, the charge applying unit charges the medium to the same polarity as the recording unit, and therefore paper dust that has not been removed by the charging unit can be prevented from adhering to the recording unit.

[0023] The present invention will be specifically described below. In the following, an inkjet printer 1 that performs recording by ejecting ink, which is an example of a liquid, onto a medium such as recording paper will be described as an example of a recording device. In the following, the inkjet printer 1 will be abbreviated as printer 1.

[0024] The XYZ coordinate system shown in each figure is a Cartesian coordinate system, with the Y axis direction being the width direction intersecting the medium transport direction and the depth direction of the device. In this embodiment, of the side surfaces that make up the periphery of the device body 2, the side surface in the +Y direction is the back surface, and the side surface in the -Y direction is the front surface. The X axis direction is the width direction of the device, and as seen from the operator of the printer 1, the +X direction is the left side and the -X direction is the right side. The -X direction is the direction in which media is fed from each media cassette, which will be described later. The +X direction is the direction in which the media is transported at a position opposite the line head 12. The Z-axis direction is the vertical direction, that is, the height direction of the device, with the +Z direction being the upward direction and the -Z direction being the downward direction.

[0025] In the following, the direction in which the medium is transported may be referred to as "downstream," and the opposite direction may be referred to as "upstream." In Figure 1, the medium transport path is indicated by a dashed line. In the printer 1, the medium is transported through the medium transport path indicated by the dashed line. From the perspective of transporting the medium, the printer 1 may be considered a medium transport device 100. In this case, the medium transport device 100 can be considered to have a configuration excluding the line head 12, which will be described later. In other words, the printer 1 can be considered to be a device equipped with the medium transport device 100 and the line head 12.

[0026] The printer 1 has a plurality of media cassettes arranged vertically below the device main body 2, which includes a line head 12 (described below), specifically a first media cassette 3, a second media cassette 4, a third media cassette 5, and a fourth media cassette 6. The symbol P indicates the media stored in each media cassette. Each media cassette is provided with a pick roller that feeds the stored media in the -X direction. Reference numerals 21, 22, 23, and 24 denote pick rollers provided for each media cassette. Further, a pair of feed rollers is provided for each medium cassette to feed the medium sent out by the pick roller further downstream. Reference numerals 25, 26, 27, and 28 denote pairs of feed rollers provided for each medium cassette. In the following, unless otherwise specified, a "roller pair" is defined as consisting of a drive roller driven by a power source such as a motor, and a driven roller that rotates in contact with the drive roller.

[0027] Symbol T1 indicates the transport path of the media sent out from each media cassette and reaching the transport roller pair 34. The media sent out from the first media cassette 3 receives a feeding force from the transport roller pair 29, 33 and is sent to the transport roller pair 34. The media sent out from the second media cassette 4 receives a feeding force from the transport roller pairs 30, 29, 33 and is sent to the transport roller pair 34. The media sent out from the third media cassette 5 receives a feeding force from the transport roller pairs 31, 30, 29, 33 and is sent to the transport roller pair 34. The media sent out from the fourth media cassette 6 receives a feeding force from the transport roller pairs 32, 31, 30, 29, 33 and is sent to the transport roller pair 34.

[0028] The medium receiving the feeding force from the transport roller pair 34 is sent to a position between the line head 12, which is an example of a recording unit, and the transport belt 53, that is, a recording position facing the line head 12. The transport roller pair 34 constitutes a transport unit that transports the medium between the line head 12 and the transport belt 53. The line head 12 performs recording by ejecting ink, which is an example of a liquid, onto the surface of the medium. The line head 12 is an ink ejection head in which multiple nozzles 13 that eject ink are arranged to cover the entire area in the width direction of the medium, and is configured as an ink ejection head that can record across the entire width of the medium without moving in the width direction of the medium. However, the ink ejection head is not limited to this, and may be of a type that is mounted on a carriage and ejects ink while moving in the width direction of the medium.

[0029] The line head 12 according to this embodiment employs a piezoelectric element, which is a piezoelectric element whose volume changes when a voltage is applied. By controlling the drive waveform of the piezoelectric element, the movement of the meniscus of the nozzle 13 can be controlled, thereby controlling the size and ejection speed of the ink droplets ejected. In this embodiment, the multiple nozzles 13 are composed of multiple nozzles 13 that eject yellow ink, multiple nozzles 13 that eject magenta ink, multiple nozzles 13 that eject cyan ink, and multiple nozzles 13 that eject magenta ink.

[0030] Next, the conveyor belt 53 is an endless belt that is wound around a first roller 54 and a second roller 55, and is rotated by driving the first roller 54 by a belt drive motor 89 (see FIG. 3). The medium is attracted to the belt surface of the conveyor belt 53 and conveyed to a position facing the line head 12. The first roller 54, the second roller 55, and the conveyor belt 53 constitute a belt unit 52. The belt unit 52 has the first roller 54 as a rotation axis, and is provided so as to be rotatable by a power source (not shown).

[0031] The medium on whose first side has been recorded by the line head 12 is sent by the transport roller pair 35 located downstream of the transport belt 53 toward either the transport roller pair 36 or the transport roller pair 40. A path switching flap (not shown) is provided downstream of the transport roller pair 35, and the medium receiving the feeding force from the transport roller pair 35 is sent by this path switching flap to either the transport roller pair 36 or the transport roller pair 40.

[0032] When recording is not performed on the second side of the medium, which is opposite to the first side, i.e., when double-sided recording is not performed, the medium is sent from transport roller pair 35 to transport roller pair 36, and is discharged through discharge path T4 to discharge tray 8. Discharge path T4 is provided with transport roller pair 38 and transport roller pair 39.

[0033] When recording is to be performed on both the first side and the opposite second side of the medium, i.e., when double-sided recording is to be performed, the medium is sent from transport roller pair 35 towards transport roller pair 40 and enters switchback path T2. The rotation direction of transport roller pair 40 is then switched, and the medium enters reversal path T3 and is sent to transport roller pair 34 by transport roller pairs 41, 42, and 43.

[0034] Reference numerals 10A and 10B denote ink storage units serving as liquid storage units that store ink before ejection. The ink to be ejected from the line head 12 is supplied from the ink storage units 10A and 10B to the line head 12 via tubes (not shown). The ink storage unit 10A stores black ink, for example. The ink storage unit 10B stores yellow, magenta, and cyan ink, for example.

[0035] Reference numeral 9 denotes a cap unit having a cap portion 9a that caps the line head 12. The cap unit 9 is provided so as to be displaceable by a power source (not shown) between a separated position (see FIG. 1) where the cap portion 9a is separated from the line head 12 and a cap position (not shown) where the cap portion 9a caps the head surface 12a of the line head 12.

[0036] Reference numeral 11 denotes a waste liquid storage section that stores ink as waste liquid discharged from the line head 12 toward the cap section 9a for maintenance. The ink as waste liquid discharged from the line head 12 toward the cap section 9a for maintenance is sent from the cap section 9a to the waste liquid storage section 11 via a tube (not shown).

[0037] The above is an outline of the overall configuration of the printer 1, and the control unit 80 will be described below with reference to FIG. The control unit 80 performs various controls, including recording control, in the printer 1. Note that Fig. 2 mainly illustrates the components necessary for the following explanation, and does not illustrate other components. The control unit 80 is electrically connected to an output system including a feed motor 87, a conveying motor 88, a belt drive motor 89, a charging unit drive motor 90, a line head 12, a first power supply unit 71, a second power supply unit 72, and a third power supply unit 73.

[0038] A feed motor 87 is a power source for each of the pick rollers and each of the feed roller pairs described above. A transport motor 88 is a power source for each of the transport roller pairs described above. A belt drive motor 89 is a drive source for the transport belt 53. A charging unit drive motor 90 is a drive source for a rotating unit 60 (see FIG. 3) that constitutes a charge applying unit 59 described later. Each of the above motors is, for example, a DC motor. The feed motor 87 and the transport motor 88 are provided with rotary encoders (not shown), and the control unit 80 can detect the rotation direction, rotation amount, and rotation speed of each of the motors using these rotary encoders. That is, the control unit 80 can detect the drive direction, drive amount, and drive speed of each of the pick rollers, each of the feed roller pairs, and each of the transport roller pairs.

[0039] Furthermore, a first rotation detector 91, a second rotation detector 92, a first reference detector 93, and a second reference detector 94 are electrically connected to the control unit 80 as an input system. The first rotation detection unit 91 is a detection unit for detecting the rotation of the rotating unit 60, which will be described later, and is a rotary encoder that includes a rotary scale (not shown) and a detection unit that detects this rotary scale. The rotary scale that constitutes the first rotation detection unit 91 can be provided on any of the rotating unit 60, the charging unit drive motor 90, or a gear (not shown) that transmits driving force from the charging unit drive motor 90 to the rotating unit 60. The second rotation detection unit 92 is a detection unit for detecting the rotation of the conveyor belt 53, and is a rotary encoder equipped with a rotary scale (not shown) and a detection unit for detecting this rotary scale. The rotary scale constituting the second rotation detection unit 92 can be provided on any of the first roller 54, the second roller 55, the belt drive motor 89, or a gear (not shown) that transmits driving force from the belt drive motor 89 to the first roller 54.

[0040] The first reference detection unit 93 is a detection unit for detecting the reference position of rotation of the rotating unit 60, which will be described later, and can be composed of a rotation flag (not shown) and a detection unit that detects this rotation flag. The rotation flag that constitutes the first reference detection unit 93 can be provided in any of the rotating unit 60, the charging unit drive motor 90, or a gear (not shown) that transmits driving force from the charging unit drive motor 90 to the rotating unit 60. The second reference detection unit 94 is a detection unit for detecting the reference position of the rotation of the conveyor belt 53, and can be composed of a rotation flag (not shown) and a detection unit for detecting this rotation flag. The rotation flag constituting the second reference detection unit 94 can be provided on any of the first roller 54, the second roller 55, the belt drive motor 89, and a gear (not shown) that transmits driving force from the belt drive motor 89 to the first roller 54. The control unit 80 can align the rotation phase of the conveyor belt 53 with that of a rotating unit 60 (described later) based on the detection information from the first rotation detection unit 91, the second rotation detection unit 92, the first reference detection unit 93, and the second reference detection unit 94. In particular, it can align suction holes 53a of the conveyor belt 53 (described later) with electrode-less portions 60a (described later).

[0041] Next, the control unit 80 includes a CPU 81 that executes a computer program, in other words, software, a volatile memory 82, and a nonvolatile memory 83. The CPU 81 performs various calculations required to execute a program 84 stored in the nonvolatile memory 83. The volatile memory 82 is used as a temporary data storage area. The nonvolatile memory 83 stores the program 84 and control parameters 85 required to execute the program 84. The program 84 includes programs that execute various processes described below, and the control parameters 85 include parameters for executing the program 84. The various processes described below are realized when the control unit 80 executes the program 84.

[0042] Next, the conveyor belt 53, the charge applying unit 59, and the charging unit 66 will be described with reference to FIG. 3 and subsequent figures. The conveyor belt 53 has a plurality of suction holes 53a (see FIG. 5) formed in a staggered pattern. As shown in FIG. 3, a negative pressure chamber 58 and a backup plate 57, which is an example of a support portion that supports the conveyor belt 53, are provided inside the conveyor belt 53. A negative pressure is created in the negative pressure chamber 58 by a suction fan (not shown), and the negative pressure is applied to the backup plate 57. A hole (not shown) is formed in the backup plate 57, and this hole is configured to communicate with the suction holes 53a of the conveyor belt 53. As a result, the medium on the conveyor belt 53 is sucked by the suction holes 53a and adsorbed to the conveyor belt 53. In other words, the conveyor belt 53 conveys the medium by rotating while adsorbing the medium via the plurality of suction holes 53a.

[0043] A charge applying unit 59 is provided upstream of the line head 12, which charges the medium transported by the transport belt 53. The charge applying unit 59 is disposed opposite the transport belt 53 at a distance so as to ensure a gap between the charge applying unit 59 and the medium attracted to the transport belt 53. A voltage is applied to the charge applying unit 59 by a first power supply unit 71. A charging unit 66 is provided downstream of the charge applying unit 59 in the medium transport direction. The charging unit 66 is disposed opposite the conveyance belt 53 at a distance so as to form a gap between the charging unit 66 and the medium transported by the conveyance belt 53. In this embodiment, the charging unit 66 is a plate-shaped member extending in the transport direction and the width direction.

[0044] A voltage is applied to the charging unit 66 by the second power supply unit 72. The charging unit 66 is charged to a polarity opposite to the polarity of the medium charged by the charge providing unit 59. When a negative voltage is applied to the charge providing unit 59 by the first power supply unit 71, a positive voltage is applied to the charging unit 66 by the second power supply unit 72. As a result, the charge providing unit 59 becomes negatively charged and the charging unit 66 becomes positively charged.

[0045] The medium and paper dust adhering to the medium are negatively charged by the charge applying unit 59. The negatively charged paper dust is attracted to the positively charged charging unit 66 by Coulomb force and is removed. The charging portion 66 may be made of a conductor such as metal, or may be made of an insulator such as resin.

[0046] The line head 12 includes a nozzle plate 14 that forms the openings of the nozzles 13, and a voltage is applied to the nozzle plate 14 by a third power supply unit 73. In this embodiment, when a negative voltage is applied to the charge applying unit 59 by the first power supply unit 71, a negative voltage is applied to the nozzle plate 14 by the third power supply unit 73. This causes the nozzle plate 14 to be negatively charged. In other words, the charge applying unit 59, which will be described later, charges the medium to the same polarity as the nozzle plate 14 of the line head 12. Because the paper dust adhering to the medium is negatively charged, the paper dust is less likely to adhere to the negatively charged nozzle plate 14. In other words, the paper dust that has not been removed by the charging unit 66 can be prevented from adhering to the line head 12. The nozzle plate 14 may be made of a conductor such as a metal, or may be made of an insulator. The polarities of the charge imparting unit 59, the charge unit 66, and the nozzle plate 14 may be reversed to those described above.

[0047] Next, a detailed description will be given of the charge applying unit 59. The charge applying unit 59 has a rotating unit 60 having a rotation axis along the Y-axis direction, that is, the width direction which is a direction intersecting the medium transport direction. 4 and 5, the rotating unit 60 includes a rotating shaft 61 having a rotation axis along the width direction, and a rotating plate 62. A plurality of rotating plates 62 are provided along the width direction of the rotating shaft 61. The rotating plates 62 are fixed to the rotating shaft 61 and rotate together with the rotating shaft 61. Electrical conduction is ensured between the rotating shaft 61 and the rotating plate 62, and a voltage is applied to the rotating shaft 61 by a first power supply unit 71.

[0048] A plurality of first needle electrodes 63 are arranged on the rotating plate 62 around the rotation axis of the rotating part 60. Electrical conduction is ensured between the rotating plate 62 and the first needle electrodes 63. Since a plurality of rotating plates 62 are provided along the width direction, a plurality of first needle electrodes 63 are also arranged along the width direction. In this embodiment, the rotary shaft 61, the rotary plate 62, and the first needle electrode 63 are made of a conductive material such as metal. In this embodiment, the rotating part 60 is formed by providing a rotating plate 62 having a first needle electrode 63 arranged circumferentially on the rotating shaft 61, but the first needle electrode 63 may also be provided directly on the outer periphery of the rotating shaft 61, for example.

[0049] The rotating plate 62 is provided with an electrode-free portion 60a, which is a portion where the first needle electrode 63 is not provided. Since a plurality of rotating plates 62 are provided along the width direction, a plurality of electrode-free portions 60a are also arranged along the width direction. 5, the positions of the first needle electrodes 63 arranged in the width direction are the same as the positions of the suction holes 53a. Similarly, the positions of the electrode-free portions 60a in the width direction are the same as the positions of the suction holes 53a.

[0050] As the conveyor belt 53 and the rotating unit 60 rotate, the first needle electrode 63 faces an area between two suction holes 53a located in the conveyance direction on the conveyor belt 53. In Fig. 5, the hatched area A1 is the area on the conveyor belt 53 that faces the first needle electrode 63. In this specification, the fact that the first needle electrode 63 or a second needle electrode 65 (described later) faces the conveyor belt 53 means that there may or may not be a medium between the conveyor belt 53 and the charge applying unit 59. The electrode-free portion 60a faces the suction hole 53a as the conveyor belt 53 and the rotating portion 60 rotate. In this specification, the electrode-free portion 60a facing the conveyor belt 53 means that there is no medium between the conveyor belt 53 and the charge applying portion 59.

[0051] 4, the symbol Gp denotes the distance between two suction holes 53a in the conveyance direction. In this embodiment, two electrode-free portions 60a are provided in the circumferential direction of the rotating plate 62, and the circumferential distance Sp is equal to the distance Gp between the two suction holes 53a. This allows the electrode-free portions 60a provided in two locations in the circumferential direction of the rotating plate 62 to face the suction holes 53a located multiple times along the conveyance direction. The control unit 80 then controls the belt drive motor 89 and the charging unit drive motor 90 so that the electrode-free portions 60a face the suction holes 53a.

[0052] As described above, as the conveyor belt 53 and the rotating unit 60 rotate, the first needle electrode 63 faces the area between the two suction holes 53a located in the conveyance direction on the conveyor belt 53. Therefore, paper dust adhering to the medium can be charged even between the two suction holes 53a in the conveyance direction. This makes it possible to remove paper dust located between the two suction holes 53a in the conveyance direction. Furthermore, as the conveyor belt 53 and the rotating part 60 rotate, the electrode-free part 60a faces the suction hole 53a, which prevents the backup plate 57 from becoming charged by the first needle electrode 63, thereby preventing problems associated with the backup plate 57 becoming charged. Furthermore, since the rotation of the rotating part 60 causes the electrode-free part 60a to face the suction hole 53a, noise generated by the movement of the member can be suppressed.

[0053] In this embodiment, the rotation direction of the rotating unit 60 is opposite to the rotation direction of the conveyor belt 53. Specifically, in this embodiment, the conveyor belt 53 rotates in rotation direction C2, and the rotating unit 60 rotates in rotation direction C1. As a result, when the first needle electrode 63 faces the medium, the first needle electrode moves together with the medium in the conveyance direction. This makes it possible to prevent damage to the medium even if the medium comes into contact with the first needle electrode 63, and also to prevent jams from occurring.

[0054] In this embodiment, as shown in Fig. 4, the plurality of suction holes 53a are arranged in a staggered pattern on the conveyor belt 53. The non-electrode portions 60a are positioned so as to face the plurality of suction holes 53a arranged in a staggered pattern. Specifically, as shown in Fig. 5, the plurality of rotating plates 62 arranged along the width direction are arranged so that the positions of the non-electrode portions 60a are alternately shifted, thereby enabling the non-electrode portions 60a to face the plurality of suction holes 53a arranged in a staggered pattern. Even when the suction holes 53a are arranged in a staggered pattern in this way, it is possible to prevent the backup plate 57 from being charged by the first needle electrode 63, thereby preventing problems associated with charging the backup plate 57.

[0055] In this embodiment, the driving source that rotates the rotating unit 60 is a first driving source, and the second driving source that rotates the conveyor belt 53 is provided. In this embodiment, the first driving source is the charging unit driving motor 90, and the second driving source is the belt driving motor 89. Then, based on the detection information from the first rotation detection unit 91, the second rotation detection unit 92, the first reference detection unit 93, and the second reference detection unit 94, the control unit 80 controls the charging unit drive motor 90 and the belt drive motor 89 so that the suction hole 53a and the electrodeless portion 60a face each other. With this configuration, the suction holes 53a and the electrode-free portions 60a can be reliably opposed to each other.

[0056] The drive source for the rotating unit 60 may also serve as the drive source for the conveyor belt 53. Fig. 6 shows such an embodiment, which includes a power transmission mechanism 75. The power transmission mechanism 75 includes a gear 76 that rotates coaxially with the first roller 54, a gear 77 that rotates coaxially with the rotating unit 60, and a gear 78 that meshes with both gear 76 and gear 77. As a result, a driving force is transmitted from gear 77 to gear 76 via gear 78, and the conveyor belt 53 rotates together with the rotating unit 60. The power transmission mechanism 75 synchronizes the rotation of the conveyor belt 53 with the rotation of the rotating unit 60 so that the suction holes 53a and the electrode-free portions 60a face each other. This configuration can prevent increases in the cost of the device. Furthermore, by using a power transmission mechanism 75 that synchronizes the rotation of the conveyor belt 53 with the rotation of the rotating unit 60 so that the suction holes 53a and the electrode-free portions 60a face each other, the suction holes 53a and the electrode-free portions 60a can be reliably positioned opposite each other.

[0057] In another embodiment, the rotating unit may include a plurality of second needle electrodes arranged around the rotation axis. Fig. 7 shows a charge applying unit 59A according to another embodiment, with reference numeral 60A indicating the rotating unit according to the other embodiment. The rotating unit 60A includes a rotating plate 62 including a first needle electrode 63 and a rotating plate 64 including a second needle electrode 65. The rotating plate 64 has the same configuration as the rotating plate 62, but differs from the rotating plate 62 in that it does not include an electrode-free portion 60a. In other words, the second needle electrode 65 is provided around the entire circumference of the rotating plate 64. The position of the second needle electrode 65 in the width direction is such that it avoids the suction hole 53a. In FIG. 7, the dot-hatched area A2 is an area that avoids the suction holes 53a in the width direction, and the second needle electrode 65 faces this area. With this configuration, paper dust adhering to the medium can be charged by the second needle electrode 65 even in areas in the width direction where there are no suction holes 53a, making it possible to more reliably remove paper dust.

[0058] 8, an insulating member may be provided to surround the rotating part 60. The insulating member 79 is made of an insulating material and is a box-shaped member with only the portion facing the conveyor belt 53 being open. By providing such an insulating member 79, it is possible to prevent the charge applying portion 59 from charging other portions, which would cause adverse effects. In this embodiment, the insulating member 79 surrounds not only the charge imparting unit 59 but also the charging unit 66. This prevents the charging unit 66 from charging other parts and causing adverse effects. However, the insulating member 79 may surround only the charge imparting unit 59 without surrounding the charging unit 66.

[0059] It is also preferable to configure the charge applying unit 59 so that the shortest distance between the charge applying unit 59 and the conveyor belt 53 is shorter than the shortest distance between the charge applying unit 59 and other components, thereby preventing the charge applying unit 59 from charging other components and causing adverse effects.

[0060] The charging unit 66 may be configured as part of a head support member (not shown) that supports the line head 12. For example, a part of the head support member may be configured to protrude toward the conveyor belt 53, and a voltage may be applied to that part, which can then be used as the charging unit. Furthermore, the charging unit 66 is not limited to a plate-shaped member, but may be configured as a rotating belt. By applying a voltage to such a belt, paper dust can be attracted to the belt. In such a configuration, if a cleaning mechanism such as a wiper is provided on part of the belt, the adhering paper dust can be collected.

[0061] The present invention is not limited to the embodiments and modifications described above, and various modifications are possible within the scope of the invention described in the claims, and it goes without saying that these modifications are also included within the scope of the present invention. [Explanation of symbols]

[0062] 1...inkjet printer, 2...device main body, 3...first media cassette, 4...second media cassette, 5...third media cassette, 6...fourth media cassette, 8...output tray, 9...cap unit, 9a...cap section, 10A, 10B...ink storage section, 11...waste liquid storage section, 12...line head, 13...nozzle, 14...nozzle plate, 19...feed roller pair, 21, 22, 23, 24...pick roller, 25, 26, 27, 28...feed roller pair, 29-42...transport roller pair, 52...belt unit, 53...transport belt, 53a...suction hole, 54...first roller, 55...second roller, 57...backup plate, 58...negative pressure chamber, 59...charged charging unit, 60...rotating unit, 60a...electrode-free unit, 61...rotating shaft, 62...rotating plate, 63...first needle electrode, 64...rotating plate, 65...second needle electrode, 66...charging unit, 71...first power supply unit, 72...second power supply unit, 73...third power supply unit, 75...power transmission mechanism, 76...gear, 77...gear, 78...gear, 79...insulating member, 80...control unit, 81...CPU, 82...volatile memory, 83...non-volatile memory, 84...program, 85...control parameters, 87...feed motor, 88...transport motor, 89...belt drive motor, 90...charging unit drive motor, 91...first rotation detection unit, 92...second rotation detection unit, 93...first reference detection unit, 94...second reference detection unit, 100...medium transport device

Claims

1. a conveyor belt that conveys the medium by rotating while suctioning the medium through a plurality of suction holes; a support portion that supports the conveyor belt; a charge applying unit that charges the medium being transported by the transport belt; a charging unit provided downstream of the charge applying unit in the medium transport direction, the charging unit charging the medium to a polarity opposite to the polarity of the medium charged by the charge applying unit; Equipped with the charge applying unit is a rotating unit having a rotation axis along a width direction that is a direction intersecting the transport direction, the rotating unit being rotationally driven by a drive source, The rotating part is a plurality of needle electrodes arranged around the rotation axis and further arranged along the width direction; a plurality of electrode-free portions that are arranged along the width direction and are areas where the needle electrodes are not provided; and the positions in the width direction of the needle electrodes arranged along the width direction are at the positions of the suction holes, the positions in the width direction of the electrode-free portions arranged along the width direction are at the positions of the suction holes, the needle electrodes face a region between two of the suction holes located in the conveying direction of the conveying belt as the conveying belt and the rotating portion rotate, the electrode-free portion faces the suction hole as the conveyor belt and the rotating portion rotate. A medium transport device characterized by:

2. 2. The medium transport device according to claim 1, The rotation direction of the rotating part is opposite to the rotation direction of the conveyor belt. A medium transport device characterized by:

3. 2. The medium transport device according to claim 1, the plurality of suction holes are arranged in a staggered pattern on the conveyor belt, the electrode-free portion is disposed at a position capable of facing the plurality of suction holes arranged in the staggered pattern; A medium transport device characterized by:

4. 2. The medium transport device according to claim 1, the drive source that rotationally drives the rotating portion is a first drive source, and a second drive source that rotationally drives the conveyor belt; a first rotation detection unit that detects rotation of the rotating unit; a second rotation detector that detects the rotation of the conveyor belt; a first reference detection unit that detects a reference position of rotation of the rotating unit; a second reference detection unit that detects a reference position of the rotation of the conveyor belt; a control unit that controls the first drive source and the second drive source based on detection information from the first rotation detection unit, the second rotation detection unit, the first reference detection unit, and the second reference detection unit so that the suction hole and the electrode-free portion face each other; Equipped with A medium transport device characterized by:

5. 2. The medium transport device according to claim 1, the drive source also serves as a drive source for the conveyor belt, a power transmission mechanism that synchronizes the rotation of the conveyor belt with the rotation of the rotating portion so that the suction holes and the electrode-free portion face each other; A medium transport device characterized by:

6. 2. The medium transport device according to claim 1, The needle electrode is a first needle electrode, and the rotating unit includes a plurality of second needle electrodes arranged around the rotation axis, The second needle electrode is positioned in the width direction so as to avoid the suction hole. A medium transport device characterized by:

7. 2. The medium transport device according to claim 1, an insulating member surrounding the rotating part; A medium transport device characterized by:

8. The medium transport device according to any one of claims 1 to 7; a recording unit located downstream of the charging unit in the transport direction and configured to record on the medium; A recording device comprising:

9. 9. The recording apparatus according to claim 8, the charge applying unit charges the medium to the same polarity as the recording unit; A recording device characterized by:

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