JP4363373B2 - Sheet material conveying device and droplet discharge device - Google Patents

Description

  The present invention relates to a sheet material conveying apparatus that electrostatically attracts and conveys a sheet material to the surface, and a liquid droplet ejection apparatus that ejects liquid droplets to a sheet material conveyed by the sheet material conveying apparatus.

  In the conventional ink jet recording apparatus, an electrostatic chucking system in which a charger is brought into contact with the surface of the transport belt (sheet material holding member) to form an alternating charge pattern on the belt surface, and the paper is electrostatically attracted to the belt surface. Therefore, the flatness of the conveyed paper is ensured and the landing accuracy of the ink droplets is ensured (see, for example, Patent Documents 1 to 3).

  Here, conventionally, in order to form an alternating charge pattern on the surface of the transport belt, an alternating electrode in which positive and negative electrodes alternate is brought into contact with the back surface of the transport belt, or a charging roll is placed on the surface of the transport belt. An alternating voltage is applied to the charging roll by contact, or the alternating electrode is embedded in the transport belt.

However, in the ink jet recording apparatus, for example, paper dust or ink adhering to the belt surface due to long-term use can be conveyed between the belt cleaner and the charging member even if a belt cleaner is provided on the surface of the conveyor belt. Dirt adhering to the belt is inevitable. Therefore, the conventional ink jet recording apparatus has a problem in that dirt is transferred to the charging member to change the charging characteristics. Further, the charging characteristics also change when the charging member deteriorates due to wear due to contact with the conveying belt. Normally, this charging member is designed to have a predetermined volume resistance value for the purpose of stabilizing the discharge characteristics, but the volume resistance value is reduced due to deterioration due to wear, adhesion of dirt, dirt adsorbing surrounding moisture, etc. It will change, resulting in a change in charge amount and a change in charge uniformity due to a change in charging efficiency. Further, embedding the alternating electrode in the transport belt increases the cost of the transport belt.
Japanese Patent Laid-Open No. 7-137877 JP 2003-103857 A JP-A-11-151842

  The present invention has been made in view of the above facts, and forms a charge pattern alternating on the surface of the sheet material holding member in a non-contact manner with the sheet material holding member. Further, the structure of the charging member and the sheet material holding member is simplified to reduce the cost.

  A sheet material conveying apparatus according to claim 1, comprising: a sheet material holding member that conveys the sheet material while holding the sheet material; and a charging unit that applies an alternating electric field to the surface of the sheet material holding member. In the apparatus, the charging unit is provided in contact with the sheet material holding member in a non-contact manner, and a convex portion protruding to the sheet material holding member and a concave portion recessed with respect to the convex portion A charging member formed alternately and repeatedly along a direction intersecting the conveying direction of the material, and applying a voltage to the charging member to generate a discharge between the convex portion and the surface of the sheet material holding member And a voltage applying means.

  In the sheet material conveying apparatus according to the first aspect, the charging member is provided so as to face the sheet material holding member in a non-contact manner. In this charging member, convex portions protruding toward the sheet material holding member and concave portions recessed with respect to the convex portions are alternately and repeatedly formed along the direction intersecting the sheet material conveying direction. A voltage is applied to the charging member by the applying means, and a discharge is generated between the convex portion and the surface of the sheet material holding member.

  That is, the surface of the sheet material holding member is charged only at a position facing the convex portion of the charging member, and the position facing the concave portion is not charged. An electric field alternating in a direction intersecting with the direction (the rotation direction of the sheet material holding member) is formed.

  Thereby, an alternating electric field can be formed on the surface of the sheet material holding member without contacting the sheet material holding member and without embedding the alternating electrode in the sheet material holding member. Therefore, the charging characteristics can be maintained for a long time, and the cost of the apparatus can be reduced.

  A sheet material conveying apparatus according to a second aspect is the sheet material conveying apparatus according to the first aspect, wherein the charging member is comb-shaped.

  In the sheet material conveying device according to the second aspect, since the charging member has a comb-teeth shape, a strong electric field can be formed on the convex portion, and the electron emission performance can be improved. Therefore, the charging voltage can be lowered and the amount of ozone generated can be suppressed.

  The sheet material conveying apparatus according to claim 3 is the sheet material conveying apparatus according to claim 1 or 2, further comprising a drive unit that moves the charging member in a direction that intersects the conveying direction of the sheet material. And

  In the sheet material conveying apparatus according to claim 3, the surface of the sheet material holding member is inclined with respect to the sheet material conveying direction by moving the charging member in a direction intersecting the sheet material conveying direction by the driving unit. A charge pattern extending in the direction in which it is formed is formed. For this reason, at least a part of the end portion of the sheet material in the width direction (direction intersecting the conveyance direction) can be reliably overlapped with a position where the surface potential difference of the sheet material holding member is maximum and the adsorption force is maximized. . Therefore, the end of the sheet material in the width direction can be stably adsorbed on the surface of the sheet material holding member.

  The sheet material conveyance device according to claim 4 is the sheet material conveyance device according to any one of claims 1 to 3, wherein the crossing angle of the charging member with respect to the conveyance direction of the sheet material can be adjusted. It is characterized by that.

  In the sheet material conveying device according to claim 4, the charge pattern pitch formed on the surface of the sheet material holding member can be adjusted by making it possible to adjust the crossing angle of the charging member with respect to the sheet material conveying direction. ing. This makes it possible to adjust the electrostatic attraction force of the sheet material holding member in consideration of the releasability of peeling the sheet material from the surface of the sheet material holding member.

  The sheet material conveyance device according to claim 5 is the sheet material conveyance device according to any one of claims 1 to 4, wherein the two charging members are transported by the convex portions of each other. It is disposed so as to be offset in a direction crossing the direction, and a positive voltage is applied to one of the charging members and a negative voltage is applied to the other charging member by the voltage applying means. To do.

  In the sheet material conveying apparatus according to claim 5, the two charging members are arranged so that the convex portions of each of the charging members are offset in a direction intersecting with the conveying direction of the sheet material. A positive voltage is applied to one of the charging members, and a negative voltage is applied to the other charging member.

  As a result, a charge pattern is formed on the surface of the sheet material holding member in which positive charges and negative charges alternate in a direction intersecting the sheet material conveyance direction. Therefore, as compared with the inventions according to claims 1 to 4, the potential difference on the surface of the sheet material holding member becomes larger, and the electrostatic adsorption force on the surface of the sheet material holding member becomes larger.

  The sheet material conveying apparatus according to claim 6 is the sheet material conveying apparatus according to any one of claims 1 to 4, wherein the voltage applying unit applies an alternating voltage to the charging member. Features.

  In the sheet material conveying device according to claim 6, in addition to the charge pattern alternating on the surface of the sheet material holding member by crossing the sheet material conveying direction by applying an alternating voltage to the charging member, A charge pattern in which positive charges and negative charges alternate in the conveying direction of the sheet material is formed. As a result, a potential difference is generated on the surface of the sheet material holding member between the direction intersecting the sheet material conveyance direction and the sheet material conveyance direction, and the electrostatic adsorption force on the surface of the sheet material holding member becomes larger.

  The sheet material conveying device according to claim 7 is the sheet material conveying device according to any one of claims 1 to 6, wherein the sheet material holding member is an endless member. To do.

  In the sheet material conveying apparatus according to the seventh aspect, a charge pattern alternating in the direction intersecting the sheet material conveying direction is formed on the surface of the endless member, and the sheet material is electrostatically adsorbed.

  The sheet material conveying apparatus according to an eighth aspect is the sheet material conveying apparatus according to the seventh aspect, wherein the sheet material holding member is an endless belt.

  In the sheet material conveying apparatus according to the eighth aspect, a charge pattern alternating in a direction intersecting the sheet material conveying direction is formed on the surface of the endless belt, and the sheet material is electrostatically adsorbed.

  A sheet material conveying apparatus according to a ninth aspect is the sheet material conveying apparatus according to the seventh aspect, wherein the sheet material holding member is a drum.

  In the sheet material conveyance device according to the ninth aspect, a charge pattern alternating in a direction intersecting the sheet material conveyance direction is formed on the surface of the drum, and the sheet material is electrostatically adsorbed.

  A sheet material conveying device according to claim 10 is provided to face the surface of the sheet material holding member according to any one of claims 1 to 9 and the sheet material holding member, and the sheet material conveying device. And a droplet discharge head that discharges droplets onto the sheet material conveyed by the apparatus.

  In the droplet discharge device according to claim 10, a droplet discharge head is provided on the surface of the sheet material holding member so as to be opposed to the surface of the sheet material holding member. , Droplets are ejected.

  Here, as described above, since the charging member is not in contact with the surface of the sheet material holding member, the charging characteristics of the surface of the sheet material holding member can be maintained for a long time, and the flatness of the conveyed sheet material can be improved. Can be maintained for a long time. Thereby, the landing accuracy of the droplets on the sheet material can be maintained for a long time. Further, since it is possible to apply an alternating electric field to the surface of the sheet material holding member without embedding the alternating electrode in the sheet material holding member, the cost of the sheet material holding member can be reduced, and thus the liquid The cost of the entire droplet discharge device can be reduced.

  Since the present invention is configured as described above, it is possible to form an alternating charge pattern on the surface of the sheet material holding member without contact with the sheet material holding member. Further, the configuration of the charging member and the sheet material holding member can be simplified, and the cost can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows an ink jet recording apparatus 12 of the present embodiment. A paper feed tray 16 is provided in the lower part of the casing 14 of the ink jet recording apparatus 12, and the sheets P stacked in the paper feed tray 16 can be taken out one by one by a pickup roll 18. The taken paper P is transported by a plurality of transport roller pairs 20 constituting a predetermined transport path 22.

  A paper transport device 10 is disposed above the paper feed tray 16. In the sheet conveying apparatus 10, an endless conveying belt 28 is stretched around a driving roll 24 and driven rolls 26 and 27. A recording head array 30 is disposed above the conveyor belt 28 and faces the flat portion 28F of the conveyor belt 28. This opposed area is an ejection area SE where ink droplets are ejected from the recording head array 30. The sheet P transported along the transport path 22 is held by the transport belt 28 and reaches the discharge area SE, and ink droplets corresponding to image information are attached from the recording head array 30 in a state of facing the recording head array 30. The

  In this embodiment, the recording head array 30 has a long shape in which the effective recording area is equal to or larger than the width of the paper P (the length in the direction orthogonal to the transport direction), and is yellow (Y) and magenta (M). , Cyan (C), and Black (K), four inkjet recording heads (hereinafter referred to as recording heads) 32 corresponding to the four colors are arranged along the transport direction, so that a full-color image can be recorded. ing.

  Each recording head 32 is controlled by a head drive circuit (not shown). The head drive circuit has a configuration in which, for example, the ejection timing of ink droplets and the ink ejection port (nozzle) to be used are determined according to image information and a drive signal is sent to the recording head 32.

  The recording head array 30 may be stationary in a direction orthogonal to the transport direction. However, if the recording head array 30 is configured to move as necessary, an image with higher resolution can be obtained by multi-pass image recording. Or the failure of the recording head 32 is not reflected in the recording result.

  Four maintenance units 34 corresponding to the respective recording heads 32 are arranged on both sides of the recording head array 30. As shown in FIG. 2, when performing maintenance on the recording head 32, the recording head array 30 moves upward, and the maintenance unit 34 moves into the gap formed between the conveyance belt 28 and enters. Then, a predetermined maintenance operation (suction, wiping, capping, etc.) is performed while facing the nozzle surface.

  As shown in FIG. 3, the suction roll 36 is disposed on the upstream side of the recording head array 30. The suction roll 36 is driven while the conveyance belt 28 and the paper P are sandwiched between the suction roll 26 and the driven roll 26. Further, the charging mechanism 11 is disposed upstream of the suction roll 36 in the belt rotation direction A. The charging mechanism 11 includes a charging member 40 and a power source 38 connected to the charging member 40. The charging member 40 is disposed so as to face the driven roll 26 with the conveyance belt 28 interposed therebetween, and to be in non-contact with the surface of the conveyance belt 28. The driven roll 26 is grounded, and a surface layer that can be charged is formed on the conveyor belt 28. For this reason, when a voltage is applied to the charging member 40, a discharge occurs between the charging member 40 and the surface of the transport belt 28, and the surface of the transport belt 28 is charged. Here, an alternating electric field is formed on the surface of the conveyance belt 28, whereby the paper P is electrostatically attracted to the surface of the conveyance belt 28.

  A separation plate 41 is disposed on the downstream side of the recording head array 30 and separates the paper P from the transport belt 28. The peeled paper P is transported by a plurality of discharge roller pairs 42 constituting a discharge path 44 on the downstream side of the peeling plate 41 and discharged to a paper discharge tray 46 provided outside the housing 14.

Here, the sheet conveying apparatus 10 will be described. Note that the same reference numerals in the second to fifth embodiments denote the same components as in the first embodiment, and a description thereof will be omitted.
[First embodiment]
As shown in FIGS. 3 and 4, in the paper transport device 10, the charging member 40 is wound around the driven roll 26 of the transport belt 28 on the upstream side in the belt rotation direction A from the position where the paper P enters the transport belt 28. It faces the hung part without contact. The charging member 40 is a comb-like plate material made of conductive metal such as stainless steel, iron, aluminum, or the like that extends along a direction (hereinafter referred to as a width direction) orthogonal to the paper conveyance direction B (belt rotation direction A). Convex portions 40A that protrude toward the conveyor belt 28 and concave portions 40B that are recessed with respect to the convex portions 40A are alternately and repeatedly formed in the width direction. The convex portion 40A has an acute tip, and the distance between the tip of the convex portion 40A and the surface of the conveyor belt 28 is 0.1 mm to 5 mm. Moreover, as shown in FIG. 5, the interval P between the tips of the convex portions 40A may be 1 mm to 50 mm, but more preferably 4 mm to 10 mm.

  As shown in FIGS. 3 and 4, the driven roll 26 facing the charging member 40 with the conveying belt 28 interposed therebetween is grounded, and the conveying belt 28 has a conductive and chargeable surface layer. Is formed. The power source 38 connected to the charging member 40 is a DC power source, and applies a positive voltage of +1000 V to +5000 V to the charging member 40 continuously during sheet conveyance. As a result, a discharge is generated between the charging member 40 and the surface of the conveyor belt 28.

  Here, the distance between the tip of the convex portion 40A and the surface of the conveyor belt 28 is between the tip of the convex portion 40A and the surface of the conveyor belt 28 in a state where a positive voltage of + 1000V to + 5000V is applied to the charging member 40. On the contrary, the distance between the concave portion 40B and the surface of the conveyor belt 28 is such that the distance between the concave portion 40B and the surface of the conveyor belt 28 when a positive voltage of + 1000V to + 5000V is applied to the charging member 40. It is long enough that no discharge occurs between the two.

  For this reason, when a positive voltage of +1000 V to +5000 V is continuously applied from the power supply 38 to the charging member 40, the linear shape extends in the paper conveyance direction B only at a position facing the convex portion 40A on the surface of the conveyance belt 28. The positive charge pattern Q is formed. As a result, a charge pattern alternating in the width direction is formed on the surface of the conveyor belt 28.

  That is, an alternating electric field can be formed on the surface of the conveyor belt 28 without contacting the conveyor belt 28 and without embedding the alternating electrode in the conveyor belt 28. Accordingly, it is possible to prevent dirt, paper dust, and the like from being transferred from the conveying belt 28 to the charging member 40 and wear of the charging member 40, so that the charging characteristics can be maintained for a long time. Moreover, the cost of the apparatus can be reduced.

Further, since the charging member 40 has a comb shape, a strong electric field can be formed at the tip of the convex portion 40A, and the electron emission ability can be enhanced. Therefore, the charging voltage can be lowered and the amount of ozone generated can be suppressed.
[Second Embodiment]
As shown in FIG. 6, in the paper transport apparatus 100, the charging member 40 is supported by a support member (not shown) so as to be slidable in the width direction, and is moved in the width direction by the drive mechanism 50. The drive mechanism 50 is disposed on one end side in the longitudinal direction of the charging member 40, a motor 54 for rotating the eccentric cam 52, and disposed on the other end side in the longitudinal direction of the charging member 40. And a compression coil spring 56 that biases 40 toward one end in the longitudinal direction. The eccentric cam 52 is disposed with its circumferential surface facing one end in the longitudinal direction of the charging member 40, and the charging member 40 is pressed against the circumferential surface of the eccentric cam 52 by the urging force of the compression coil spring 56. For this reason, when the eccentric cam 52 is rotated by the motor 54, the charging member 40 moves in the width direction, and a linear positive charge pattern Q inclined with respect to the paper transport direction B is formed on the surface of the transport belt 28. Is done.

Here, the moving speed Ve of the charging member 40 is expressed by the following equation (1).
Ve ≧ 0.5 * Vb * P / Lp (where Vb is the driving speed of the conveyor belt 28, P is the pitch of the convex portion 40A, and Lp is the length of the paper P) (1)
That is, the moving speed Ve of the charging member 40 is set so that the positive charge pattern Q is shifted in the width direction by ½P or more from the rear end portion to the front end portion of the paper P. For this reason, at least one point of the end portion in the width direction of the paper P can be reliably overlapped with a position where the potential difference on the surface of the conveyance belt 28 is maximum and the adsorption force is maximum. Accordingly, the end of the paper P in the width direction can be stably adsorbed to the surface of the conveyance belt 28.

In the present embodiment, the charging member 40 is moved only to the other end side in the longitudinal direction to form the positive charge pattern Q that is inclined only toward one end side in the longitudinal direction of the charging member 40 with respect to the paper transport direction B. 7, the charging member 40 is alternately moved to one end side and the other end side in the longitudinal direction, and is inclined alternately to the other end side and one end side in the longitudinal direction of the charging member 40 with respect to the paper transport direction B. That is, a positive charge pattern Q extending zigzag in the paper conveyance direction B may be formed. In this case, since several points at the end in the width direction of the paper P can be overlapped at a position where the potential difference on the surface of the transport belt 28 is maximized, the surface of the transport belt 28 at the end in the width direction of the paper P The adsorption state can be further stabilized.
[Third embodiment]
As shown in FIGS. 8A and 8B, in the paper transport apparatus 200, the charging member 40 is disposed to face the lower flat surface 28 </ b> F ′ of the transport belt 28. Further, the charging member 40 is rotatable around a rotation shaft 40C attached to one end portion in the longitudinal direction. Since the rotation shaft 40C is substantially parallel to the normal direction of the flat surface 28F ′ of the conveyor belt 28, when the charging member 40 is rotated upstream in the belt rotation direction A, the charging member 40 is used. And the flat surface 28F ′ of the conveyor belt 28 are maintained substantially constant.

  Here, as shown in FIG. 8A, when the crossing angle of the charging member 40 with the belt rotation direction A is adjusted to a substantially right angle, the pitch of the positive charge pattern Q becomes maximum, and FIG. ), When the charging member 40 is rotated upstream in the belt rotation direction A and the crossing angle of the charging member 40 with the belt rotation direction A is decreased from a substantially right angle, the positive charge pattern Q The pitch decreases.

As described above, since the crossing angle of the charging member 40 with the belt rotation direction A can be adjusted, the density of the positive charge pattern Q formed on the surface of the transport belt 28 can be adjusted, and thus changes depending on the environment. In consideration of the peelability of the paper P from the surface of the transport belt 28, the moisture absorption of the paper P, etc., the electrostatic attraction force of the transport belt 28 can be adjusted.
[Fourth embodiment]
As shown in FIG. 9, in the paper transport apparatus 300, the two charging members 40 are placed on the driven roll 26 of the transport belt 28 on the upstream side in the belt rotation direction A from the position where the paper P enters the transport belt 28. It faces the wound part in a non-contact manner. The two charging members 40 are arranged in parallel in the belt rotation direction A so that the convex portions 40A are offset in the width direction.

One charging member 40 is connected to the power source 38 described above, and the other charging member 40 is connected to a power source 39. The power source 39 is a DC power source and applies a negative voltage of −1000 V to −5000 V to the charging member 40. Therefore, a charge pattern in which the positive charge pattern Q and the negative charge pattern Q ′ alternate in the width direction is formed on the surface of the transport belt 28. Therefore, as compared with the first to third embodiments, the potential difference on the surface of the conveyance belt 28 becomes larger, and the electrostatic adsorption force on the surface of the conveyance belt 28 becomes larger.
[Fifth Embodiment]
As shown in FIG. 10, in the paper conveyance device 400, an AC power supply 43 is connected to the charging member 40, and a positive voltage and a negative voltage are alternately applied to the charging member 40. As a result, an electric field alternating in the paper conveyance direction B is formed on the surface of the conveyance belt 28 along with an electric field alternating in the width direction. As a result, a potential difference occurs between the width direction and the sheet conveyance direction B on the surface of the conveyance belt 28, and the electrostatic adsorption force on the surface of the conveyance belt 28 becomes larger.

  As described above, since the charging member 40 is not in contact with the surface of the conveyor belt 28 as described in the first to fifth embodiments, the charging characteristics of the surface of the conveyor belt 28 can be maintained for a long time and conveyed. The flatness of the paper P can be maintained for a long time. Thereby, the landing accuracy of the ink droplets on the paper P can be maintained for a long time. Further, since it is possible to apply an alternating electric field to the surface of the conveyor belt 28 without embedding the alternating electrode in the conveyor belt 28, the cost of the conveyor belt 28 can be reduced, and thus the inkjet recording apparatus 12 can be reduced. The overall cost can be reduced.

  In the first to fifth embodiments, the ink jet recording apparatus is taken as an example to describe the liquid droplet ejecting apparatus of the present invention. However, the liquid droplet ejecting apparatus of the present invention is not limited to the ink jet recording apparatus, and is a polymer film. For droplet discharge devices in general for various industrial applications, such as the production of color filters for displays by discharging colored ink on top, and the formation of EL display panels by discharging organic EL solutions onto films It is applicable.

  Further, the sheet material conveying apparatus of the present invention is not limited to the droplet discharge apparatus and the image forming apparatus, but can be applied to other apparatuses that convey the sheet material by electrostatic adsorption to the conveying belt.

  In the present invention, the “sheet material” to be transported includes a wide range of objects that are electrostatically attracted to the transport belt. Accordingly, the sheet material naturally includes recording paper, an OHP sheet, and the like, but also includes, for example, a film serving as a base material for a display panel.

  In the first to fifth embodiments, the present invention has been described by taking as an example a configuration including an inkjet recording head that is longer than the width of the paper P. However, the present invention is not limited to this, and for example, from the width of the paper P. The present invention can also be applied to a configuration in which a short inkjet recording head is moved in the width direction of the paper P.

  In the first to fourth embodiments, the shape of the charging member 40 is a comb-teeth shape. However, the shape of the charging member 40 is not limited to a comb-teeth shape, and convex portions and concave portions are alternately and repeatedly formed. Just do it. For example, as shown in FIG. 11A, a charging member 45 in which needle-like electrodes 45A are arranged in the width direction, or a thin wire 47A molded with resin and polished at the tip as shown in FIG. Examples thereof include charging members 47 arranged at equal intervals. In the charging member 45 shown in FIG. 11A, the taper angle θ of the tip of the needle-like electrode 45A is 5 to 45 °, the material of the needle-like electrode 45A is the same as that of the comb-like electrode, and the interval between the convex portions is comb-tooth. It is desirable to be the same as the electrode. On the other hand, in the charging member 47 shown in FIG. 11B, the diameter of the wire 47A is φ10 to 100 μm, the material of the wire 47A is a metal such as Pt, Au, W, etc., the molding material is an insulating resin, and the interval between the convex portions is a comb. It is desirable to make it equivalent to a toothed electrode.

  Further, as shown in FIG. 12, the corona charger 49 described in Japanese Patent Application Laid-Open No. 11-258959 also has an appropriate design change such as increasing the interval between the protrusions 51 or increasing the distance between the protrusions 51 and the object to be charged. This is applicable. As shown in FIG. 12A, the corona charger 49 includes a pin-shaped discharge electrode 53 having a plurality of sharp tips, a first support 55 and a first support 55 for narrowly supporting the pin-shaped discharge electrode 53. The main part is composed of the second support 57 and the shield case 59 for adjusting the discharge current amount so as not to expose the high voltage application part. A power source (not shown) is connected to the pin-like discharge electrode 53 so that a high DC voltage is applied.

  As shown in FIG. 12B, an infinite number of minute protrusions 53 </ b> A are provided on the surface of the pin-like discharge electrode 53. The minute protrusions 53A are carbon black and are attached by the following electrophoresis method. First, a suspension in which acetylene black having an average particle diameter of 50 nm is dispersed in isopropyl alcohol is printed. In this suspension, a pin electrode made of Be-Cu and a counter electrode made of stainless steel were opposed to each other with a distance of 1 mm, and an AC voltage of 10 kHz and 100 V was applied therebetween. As a result, acetylene black could be attached to the vicinity of the tip of the pin-like discharge electrode 53. The pin-like discharge electrode 53 obtained in this way is placed between the first support body 55 and the second support body 57 made of polycarbonate resin and placed in the aluminum shield case 59, as shown in FIG. A corona charger 49 as shown in A) was produced.

  Thus, by forming innumerable small protrusions on the surface of the pin-like discharge electrode 53, a strong electric field can be formed and the discharge efficiency can be increased. As a result, it is possible to discharge at a low applied voltage, and the cost of the power supply can be reduced. Further, increasing the electric field in the vicinity of the discharge electrode also has the effect of reducing the amount of ozone generated, and the ozone processing cost can be reduced.

  The corona charger 49 is intended to uniformly charge an object to be charged. Therefore, in order to apply the present invention, the interval between the convex portions is the same as that of the present invention (preferably 1 to 50 mm, more preferably 4 to 10 mm), and the distance from the charging object is set to 0.1 to 5 mm.

  Furthermore, in the first to fourth embodiments, the present invention has been described by taking the configuration using the endless conveying belt 28 as an example of the sheet material holding member. However, as shown in FIG. As an example, the drum 29 is also applicable.

1 is a diagram showing an outline of an ink jet recording apparatus according to an embodiment of the present invention. 1 is a diagram showing an outline of an ink jet recording apparatus according to an embodiment of the present invention. 1 is a perspective view illustrating a paper transport device of an ink jet recording apparatus according to an embodiment of the present invention. It is a top view which shows 1st Embodiment of the paper conveying apparatus shown in FIG. FIG. 4 is an enlarged view showing a charging member provided in the paper conveying apparatus shown in FIG. 3. FIG. 4 is a diagram showing a modification of the charging mechanism provided in the paper transport device shown in FIG. 3. It is. FIG. 4 is a plan view illustrating a second embodiment of the sheet conveying device illustrated in FIG. 3. FIGS. 3A and 3C are plan views and FIG. 3B are side views showing a third embodiment of the sheet conveying apparatus shown in FIG. FIG. 6 is a plan view illustrating a fourth embodiment of the sheet conveying device illustrated in FIG. 3. FIG. 9 is a plan view illustrating a fifth embodiment of the sheet conveying device illustrated in FIG. 3. (A), (B) is a figure which shows the modification of a charging member. (A), (B) is a figure which shows the modification of a charging member. It is a perspective view which shows the modification of a paper conveying apparatus.

Explanation of symbols

10 Paper transport device (sheet material transport device)
11 Charging mechanism (charging means)
12 Inkjet recording device (droplet ejection device)
28 Conveying belt (sheet material holding member)
29 Drum (sheet material holding member)
32 Inkjet recording head (droplet ejection head)
38 Power supply (voltage application means)
39 Power supply (voltage application means)
40 Charging member 40A Convex part 40B Concave part 43 AC power supply (voltage applying means)
45 Charging member 47 Charging member 49 Corona charger (charging member)
50 Drive mechanism (drive means)
100 Paper transport device (sheet material transport device)
200 Paper transport device (sheet material transport device)
300 Paper transport device (sheet material transport device)
400 Paper transport device (sheet material transport device)
P paper (sheet material)

Claims (10)

A sheet material holding member that holds and conveys the sheet material on the surface;
A sheet material conveying device comprising a charging means for applying an alternating electric field to the surface of the sheet material holding member,
The charging means is
A convex portion that is provided in a non-contact manner and opposed to the sheet material holding member, and that protrudes toward the sheet material holding member, and a concave portion that is recessed with respect to the convex portion, intersects with the conveyance direction of the sheet material. A charging member formed alternately and along,
Voltage applying means for applying a voltage to the charging member to generate a discharge between the convex portion and the surface of the sheet material holding member;
A sheet material conveying apparatus comprising:   The sheet material conveying apparatus according to claim 1, wherein the charging member has a comb-teeth shape.   The sheet material conveying apparatus according to claim 1, further comprising a driving unit that moves the charging member in a direction that intersects a conveying direction of the sheet material.   The sheet material conveying apparatus according to claim 1, wherein an intersection angle of the charging member with respect to a sheet material conveying direction can be adjusted.   The two charging members are arranged so that the convex portions of each other are offset in a direction crossing the sheet material conveyance direction, and a positive voltage is applied to one of the charging members by the voltage applying unit. The sheet material conveying apparatus according to claim 1, wherein a negative voltage is applied to the other charging member.   The sheet material conveying apparatus according to claim 1, wherein the voltage applying unit applies an alternating voltage to the charging member.   The sheet material conveying apparatus according to claim 1, wherein the sheet material holding member is an endless member.   The sheet material conveying apparatus according to claim 7, wherein the sheet material holding member is an endless belt.   The sheet material conveying apparatus according to claim 7, wherein the sheet material holding member is a drum. A sheet material conveying device according to any one of claims 1 to 9,
A droplet discharge head that is provided opposite to the surface of the sheet material holding member and discharges droplets to the sheet material conveyed by the sheet material conveyance device;
A droplet discharge apparatus comprising:

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