JP6327315B2 - Medium transport device and recording device - Google Patents

Description

  The present invention relates to a medium conveying apparatus that conveys a medium, and a recording apparatus including the medium conveying apparatus.

  In a recording apparatus typified by a printer, a configuration in which an object to be transported, that is, a recording sheet, is transported using a transport belt may be employed. In order to obtain an appropriate recording quality in such a configuration, it is necessary to prevent the recording paper from lifting from the conveyance belt. As a means for adsorbing the recording paper to the transport belt, an apparatus using electrostatic attraction in addition to air suction has been conventionally used. Patent Documents 1 to 5 disclose such a conventional configuration.

  The printing apparatus described in Patent Document 1 is configured such that, when forming a charging pattern in which charged areas having different polarities alternate on the transport belt, the area excluding the position where the polarity is reversed and the end of the recording paper face each other. ing. That is, in the portion where the charge is switched from “+” to “−”, there are places where the charge becomes zero, but in the vicinity where such charge becomes zero, the “+” charge and the “−” charge are Since they are close to each other, there are regions where the charging is unstable due to the influence of the electric charges. In view of this, the printing apparatus described in Patent Document 1 forms a charging pattern so that the end of the recording paper is not desired in such an unstable region.

In addition, by applying an alternating voltage on the conveyor belt, the positively charged region and the negatively charged region are alternately formed because of the influence of the electric lines of force from the positive charge to the negative charge, the electric force, or the Coulomb force. Is more effective than the electrostatic adsorption force (adsorption force due to dielectric polarization) obtained by uniformly forming a charged region of the same polarity on the conveyor belt. This is because there are cases.
In addition, Patent Documents 3 to 5 disclose a configuration in which a recording medium is electrostatically attracted to a conveyance belt by applying an alternating voltage on the conveyance belt.

JP 2006-264899 A JP 2006-346870 A JP 2008-74558 A JP 2006-103022 A JP 2006-62829 A

  By the way, of the ink ejected from the ink jet recording head, the liquid droplets that do not land on the recording paper (sometimes referred to as ink mist) adhere to the components of the apparatus, or on the recording surface of the recording paper. The technical problem of adhesion has been known for some time.

  Here, the charging characteristics of the ink mist will be described below. When ink droplets are ejected from the recording head, the ink droplets are divided into main droplets that land on the recording paper and satellite droplets that float without landing on the recording paper (this becomes the above-described ink mist). The satellite droplets floating in the air are positively charged by the Leonard effect (the air around the satellite droplets is negatively charged). In addition, the longer the time for which the ink mist drifts in the air, the greater the positive charge amount of the ink mist.

  On the other hand, as in the printing apparatus described in Patent Document 1, when the charging area on the conveyor belt is formed in a strip shape by using an alternating voltage, the positive charging area and the negative charging area are alternately arranged. As a result of the charged ink mist adhering to the negatively charged region on the transport belt, the recorded image is smeared in a band shape by the ink mist, and the smeared state becomes even easier to visually recognize.

  The present invention has been made in view of such a situation, and an object of the present invention is to suppress scattering of ink mist and to record ink mist in an apparatus having a configuration for transporting an object to be transported using a transport belt. Even if it adheres to the surface, it is difficult to visually recognize it, thereby obtaining a good recording result.

  In order to solve the above problems, a medium conveying apparatus according to the first aspect of the present invention includes a conveying belt that adsorbs and conveys an object to be conveyed by electrostatic attraction, a belt charging unit that charges the conveying belt, And the belt charging unit forms at least a loading area on the conveying belt on which an object to be conveyed is placed in a charging area in which a minus charging area and a plus charging area are arranged in a grid pattern. And

  According to this aspect, the belt charging means for charging the conveyor belt is configured such that at least the object to be conveyed is placed on the conveyor belt, and the minus charging area and the plus charging area are arranged in a grid pattern. Since the liquid droplets are formed in the charged region, even if the floating droplets adhere to the transported medium due to the influence of the charged region, they are dispersed as a whole, making it difficult to visually recognize the adhesion of the droplets.

That is, if the negatively charged region and the positively charged region are alternately formed in a band shape, the positively charged droplet adheres to the negatively charged region, so that the droplet adhesion is visually recognized as a band. It becomes easy. However, as described above, the negatively charged region and the positively charged region are formed in a lattice shape, so that the droplets are dispersed as a whole, and even if the droplets adhere to the transported object, it is difficult to visually recognize them. it can.
Further, since the positively charged droplets uniformly adhere to the entire area of the transported object, the scattering of the droplets can be effectively suppressed.

  In addition, a large number of switching portions between the positive charging region and the negative charging region are formed on the conveyance belt by the lattice-shaped charging pattern. The electrostatic attraction force (Maxwell stress) applied to the medium due to the influence of the electric force line from the positive charge to the negative charge, the electric force, or the Coulomb force (Maxwell stress) is more effective as the switching area between the positive charge area and the negative charge area increases. Become. Therefore, by forming the grid-like charging pattern, the medium can be more reliably adsorbed on the conveyance belt. In particular, the edge portion of the medium can be favorably adsorbed.

  According to a second aspect of the present invention, in the first aspect, the belt charging unit is configured such that the first charging roller that is in contact with the transport belt is at a predetermined interval along a first direction that intersects the moving direction of the transport belt. A first charging unit that is arranged, and a second charging roller that is positioned downstream of the first charging unit in the movement direction of the conveyance belt and is in contact with the conveyance belt along the first direction. A second charging unit disposed between the charging rollers; and a voltage applying unit that applies an alternating voltage to the first charging unit and the second charging unit. .

  According to this aspect, the belt charging unit includes the first charging unit and the second charging unit configured by the charging roller, and the voltage applying unit that applies an alternating voltage to the first charging unit. The belt charging means can be constructed simply and at low cost.

  According to a third aspect of the present invention, in the first aspect, the belt charging unit is electrically insulated from the first region to which a positive voltage is applied along the circumferential direction, and the first region. A charging unit comprising: a second region to which a negative voltage is applied; and a charging unit in which a charging roller is disposed at a predetermined interval along a first direction intersecting a moving direction of the transport belt; and the first region And a voltage applying means comprising a DC power supply for applying a negative voltage to the second region and a positive voltage to the second region, respectively.

  According to this aspect, since the belt charging unit includes the charging unit configured by the charging roller and the voltage applying unit that applies a potential to the charging unit, the structure of the belt charging unit is simplified. And it can comprise at low cost.

  According to a fourth aspect of the present invention, there is provided a medium conveying apparatus according to any one of the first to third aspects, wherein a recording head that performs recording on a medium, and the first conveying unit disposed below the recording head. And a recording apparatus. According to this aspect, in the recording apparatus, it is possible to obtain the same effect as any of the first to third aspects described above.

  According to a fifth aspect of the present invention, in the fourth aspect, a voltage application member to which a positive voltage is applied is provided at a position downstream of the recording head and opposed to the mounting surface in the medium conveyance path. It is characterized by that.

  The droplets ejected from the recording head tend to scatter to the downstream side in the transport direction due to the action accompanying the movement of the transport belt (the action of the air flow). According to this aspect, since the voltage application member to which a positive voltage is applied is provided at a position downstream of the recording head in the medium conveyance path and facing the mounting surface, the medium is formed on the conveyance belt. An electric field is formed between the negatively charged region and the voltage application member, so that the scattered droplets can be effectively attached to the conveying belt side, and the droplets can be effectively prevented from scattering. it can.

FIG. 3 is a side view of a recording unit in the ink jet printer according to the present invention. (A) is a plan view showing the configuration of the belt charging means according to the first embodiment, (B) is a plan view schematically showing the first embodiment of the charging pattern on the conveying belt. (A) is a top view which shows the structure of the belt charging means which concerns on 2nd Example, (B) is a top view which shows typically the 2nd Example of the charging pattern on a conveyance belt. (A) is a top view which shows the structure of the belt charging means which concerns on 3rd Example, (B) is a top view which shows typically the 3rd Example of the charging pattern on a conveyance belt. The top view which shows typically the 4th Example of the charging pattern on a conveyance belt. The top view which shows the structure of a belt charging means.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiments described below, and various modifications are possible within the scope of the invention described in the claims. The examples of the present invention will be described below on the premise that these are included in the scope of the present invention.

FIG. 1 is a side view of a recording unit of an ink jet printer 1 which is an embodiment of a recording apparatus of the present invention. FIG. 2A is a plan view showing a configuration of a belt charging unit according to a first example. FIG. 3B is a diagram schematically illustrating a belt charging pattern according to the first embodiment, FIG. 3A is a plan view illustrating a configuration of a belt charging unit according to the second embodiment, and FIG. 3B is a second embodiment. FIG. 4A schematically shows a belt charging pattern according to the example, FIG. 4A is a plan view showing the configuration of the belt charging means according to the third embodiment, and FIG. 4B shows a belt charging pattern according to the third embodiment. FIG.
FIG. 5 is a plan view schematically showing a fourth embodiment of the charged pattern state on the conveyor belt, and FIG. 6 is a plan view showing the configuration of the belt charging means.

  In the xyz coordinate system shown in each figure, the x direction and the y direction are horizontal directions, of which the x direction is the paper width direction and the belt width direction (device depth direction), and the y direction is the device direction. These are the left-right direction, the belt moving direction, and the paper transport direction. The z direction is the direction of gravity (the device height direction).

  In FIG. 1, the ink jet printer 1 includes a feed roller 2, and the feed roller 2 supplies a recording paper P as an example of a transported object onto a transport belt 9. On the further upstream side of the feed roller 2, there is provided a feeding means including a detachable paper cassette for storing the recording paper, a feeding roller for feeding the recording paper P from the paper cassette, and the like. In FIG. 1, the feeding means is not shown. Also, the discharge means for discharging the recording sheet P on which recording has been performed is not shown.

  The conveyance belt 9 is an endless belt for adsorbing and conveying the recording paper P on the belt surface, and is entrained between the driving roller 7 and the driven roller 8. The driving roller 7 and the driven roller 8 arranged on the downstream side thereof are arranged in parallel in a substantially horizontal plane at a predetermined interval, whereby the conveying belt 9 is located between the driving roller 7 and the driven roller 8. Both the upper part and the lower part of the belt part located in the position are substantially horizontal. However, the present invention is not limited to this, and when the diameters of the driving roller 7 and the driven roller 8 are different, if the upper part of the transport belt 9 is substantially horizontal, the lower part does not need to be horizontal.

  The drive roller 7 is configured to be rotationally driven by a drive motor (not shown), and this drive motor is driven and controlled by the control unit 11 so that the transport belt 9 is moved in a predetermined direction at a predetermined timing. The motor is driven by a predetermined movement amount at a predetermined movement speed. In addition, the arrow (right arrow and left arrow) in FIG. 1 shows a belt moving direction, and the curved arrow attached to the driving roller 7 and the driven roller 8 shows the rotation direction of both rollers.

As will be described later, the conveyor belt 9 is charged to a predetermined state by the belt charging unit 14, thereby electrostatically adsorbing the recording paper P. For this reason, the conveyor belt 9 is made of an insulating material such as PET, polyimide, fluorine resin, or rubber having at least the surface (outer peripheral surface) having a medium resistance (1 × 10 ¹⁰ Ω / □ or less), and is necessary. Accordingly, carbon black or a conductive filler is mixed to adjust the resistance value, and the amount of retained charge for charging is adjusted.

  The inkjet recording head 3 is disposed above the conveyance belt 9 so as to face the surface of the conveyance belt 9 that is flat. The inkjet recording head 3 is, for example, yellow (Y), magenta (M), cyan (C), or black (K) 4 in order from the moving belt 9 moving direction, that is, the upstream side of the recording paper P conveying direction. It has a nozzle row (not shown) that ejects colored ink droplets (droplets). Then, under the control of the control unit 11, a color image is formed on each recording sheet P conveyed by the conveying belt 9 at a predetermined timing.

  Note that an ink tank (not shown) in which inks of these colors Y, M, C, and K are stored in the apparatus main body (not shown) of the inkjet printer 1 is detachable from or attached to the apparatus main body. Ink is supplied from the ink tank to the inkjet recording head 3 through an ink tube (not shown).

  In the present embodiment, the ink jet recording head 3 is a long head along the width direction (x direction) of the transport belt 9 which is a direction orthogonal to the paper transport direction, that is, the most recording paper expected to be used. This is a non-scanning head formed to a length that can cover the entire width of a large size paper. However, the present invention is not limited to this, and may be a scanning head that discharges ink while moving in the paper width direction (x direction), that is, a so-called serial type recording head.

  In addition, the nozzle plate 3a formed with an ink discharge hole (not shown) that forms a surface facing the conveying belt 9 in the inkjet recording head 3 may be formed of a conductor such as metal, or an insulating material such as silicon. It may be formed of a body or a semiconductor. When the nozzle plate 3a is formed of a conductor such as a metal, when the nozzle plate 3a is grounded, the negative charge of the ink moving in the nozzle plate 3a moves to the nozzle plate 3a side, so that the ink is ejected. Thus, the charged state changes to the positive charging side.

  The lower surface (nozzle formation surface) of the nozzle plate 3a is directed to the upper surface of the transport belt 9, that is, the paper placement surface 9a on which the recording paper P is placed, and the nozzle formation surface is the paper placement surface of the transport belt 9. 9a and a predetermined distance away from each other.

  A second paper detection sensor 5 is provided at a position on the surface of the ink jet recording head 3 that faces the conveyor belt 9 and away from the nozzle plate 3a. The second paper detection sensor 5 is an optical sensor, and includes a light emitting unit and a light receiving unit (not shown), receives light emitted from the light emitting unit at the light receiving unit, and sends a detection signal based on the amount of light to the control unit 11. And send. Thereby, the control unit 11 can detect the passage of the leading edge and the trailing edge of the recording paper P, and can grasp the length of the recording paper P together with the driving speed of the conveying belt 9.

  A first paper detection sensor 4 is provided downstream of the feed roller 2 and upstream of the transport belt 9, that is, between the feed roller 2 and the transport belt 9. The first paper detection sensor 4 is an optical sensor having the same configuration as the second paper detection sensor 5, and the control unit 11 of the inkjet printer 1 receives a detection signal from the first paper detection sensor 4, The timing at which the recording paper P reaches the conveying belt 9, more specifically, the positional relationship between the recording pattern P and a charging pattern (described later) formed on the conveying belt 9 can be controlled. In FIG. 1, the first paper detection sensor 4 is shown in the vicinity of the recording paper P placement area of the transport belt 9. There must be a distance equal to or greater than the distance to the second charging unit 18 (second charging roller 20). As a result, it is possible to grasp the area where the leading edge or the trailing edge of the recording paper P is placed on the conveying belt 9, so that the charging of the conveying belt 9 can be controlled.

  Subsequently, a belt charging unit 14 is provided below the driving roller 7 that drives the conveying belt 9. The belt charging unit 14 includes the first charging unit 15, the second charging unit 18, the two charging units, and the voltage applying unit 12 that applies a voltage to the charging units.

  The voltage application means 12 is a power supply device configured by an AC power supply, a DC power supply, a known switching regulator, and the like, and is a power supply device that can perform rectification of alternating voltage, polarity inversion, pulse modulation, and the like. The voltage application unit 12 applies a predetermined alternating voltage to the first charging unit 15 and the second charging unit 18 under the control of the control unit 11.

  On the other hand, a static eliminator 10 is provided below the driven roller 8. The static eliminator 10 is a static eliminator for eliminating the charged state of the conveyor belt 9, and is located upstream of the belt charger 14 in the belt driving direction, and the belt charger 14 is controlled under the control of the controller 11. Before the charging pattern is formed on the conveyor belt 9, the charged state of the conveyor belt 9 is eliminated in advance. The static eliminator 10 can use various types of static eliminator such as a well-known ion-type static eliminator or a self-discharge rectifier represented by a static eliminator brush.

  Reference numeral 22 denotes a voltage application member provided at a position downstream of the ink jet recording head 3 and facing the paper placement surface 9 a of the conveyor belt 9. The voltage application member 22 is formed of a conductive material, and a positive voltage is applied.

  Thereby, the following effects are obtained. That is, the ink droplets ejected from the ink jet recording head 3 and floating tend to scatter to the downstream side in the transport direction due to the action accompanying the movement of the transport belt 9 (the action of the air flow). However, an electric field is formed between the negatively charged region portion of the sheet placement surface 9a of the transport belt 9 and the voltage-applied member 22, thereby effectively adhering the scattered ink droplets to the transport belt 9 side. And ink droplets can be effectively prevented from scattering.

  Reference numeral 24 denotes a cleaning roller. The cleaning roller is provided so as to be able to come into contact with the conveyance belt 9, and removes ink droplets, foreign matters, and the like attached to the conveyance belt 9 by being in contact with the conveyance belt 9. The cleaning roller 24 is rotationally driven by a motor (not shown) in a direction that opposes the moving direction of the conveyor belt 9, thereby functioning to wipe the surface of the conveyor belt 9. Note that not only the cleaning roller 24 but also a wiper or the like that can clean the transport belt 9 may be used.

■■■ First Example ■■■
Next, a first embodiment of the charging pattern formed by the belt charging unit 14 will be described with reference to FIG.
The present embodiment is characterized in that the placement area on which the recording paper P is placed on the conveyance belt 9 is formed in a charging area in which a minus charging area and a plus charging area are arranged in a grid pattern.

  FIG. 2B schematically shows such a charging pattern, and a region indicated by a symbol Ep (a hatched region) indicates a positively charged region (a region where a positive charge is generated) by a symbol En. Regions (non-hatched regions) indicate negatively charged regions (regions where negative charges are generated), respectively.

  When a charging area extending in the sheet width direction is seen at an arbitrary position in the sheet conveyance direction, the charging area Ck + 1 starts from the minus charging area En, and toward the right in the figure, the plus charging area Ep and the minus charging area En. , ... are alternately located. The next charging area Ck + 2 starts from the positive charging area Ep and is alternately positioned with the negative charging area En, the positive charging area Ep,. In the present embodiment, there is almost no gap between the positively charged region Ep and the negatively charged region En in the paper width direction.

  Further, when the charging area extending in the sheet conveyance direction is viewed at an arbitrary position in the sheet width direction, the charging area Rk + 1 starts from the minus charging area En, and the plus charging area Ep and minus charging are directed upward in the figure. It is located alternately with the regions En,. The next charging region Rk + 2 starts from the positive charging region Ep and is alternately positioned with the negative charging region En, the positive charging region Ep,... Upward in the figure. In the paper transport direction, an uncharged area having a certain width is formed between the positively charged area Ep and the negatively charged area En. This non-charged region is a part where the polarity changes when an alternating voltage is applied, and strictly includes a region where no voltage is applied (non-charged region) and a region where voltage is applied but slightly (weakly charged region). It is.

  As described above, in this embodiment, the belt charging unit 14 forms the loading area on the conveying belt 9 where the recording paper is placed in a charging area in which the minus charging area En and the plus charging area Ep are arranged in a grid pattern. To do. As a result, even if floating ink droplets adhere to the recording paper due to the influence of the charged region, they are dispersed as a whole, making it difficult to visually recognize the adhesion of the ink droplets.

  In other words, if the negatively charged region and the positively charged region are alternately formed in a band shape, the positively charged ink droplets adhere to the negatively charged region, so that the ink droplet adhesion is visually recognized as a band. It becomes easy. However, since the negatively charged region En and the positively charged region Ep are formed in a lattice shape as described above, ink droplets are dispersed as a whole, and even if floating ink mist adheres to the recording paper, it is difficult to visually recognize it. can do. In addition, since the positively charged ink droplets uniformly adhere to the entire area of the recording paper, scattering of the ink droplets can be effectively suppressed.

  In addition, a large number of switching portions between the positive charging region Ep and the negative charging region En are formed on the conveyor belt 9 by the lattice-shaped charging pattern. The electrostatic force (Maxwell stress) applied to the medium due to the influence of the electric lines of force from the positive charge to the negative charge, the electric force, or the Coulomb force (Maxwell stress) is more effective as the switching area between the positive charging area Ep and the negative charging area En increases. It becomes the target. Therefore, by forming the grid-like charging pattern, the recording paper can be more reliably adsorbed onto the conveyance belt 9. In particular, the edge portion of the recording paper P can be adsorbed satisfactorily.

  The belt charging means 14 for forming the lattice-like charging pattern as described above can be configured, for example, as shown in FIG. In FIG. 2A, the belt charging unit 14 includes the first charging unit 15, the second charging unit 18, and the voltage applying unit 12.

  The first charging unit 15 includes a first charging roller 17 in contact with the transport belt 9 on a shaft 16 that extends in a belt width direction (x direction) that is a first direction that intersects the moving direction of the transport belt 9 (y direction). And arranged at predetermined intervals. The second charging unit 18 has a second charging roller 20 in contact with the conveying belt 9 positioned on the upstream side (upstream side in the belt movement direction) of the first charging unit 15 and along a shaft 19 extending in parallel with the shaft 16. It is arranged so as to be positioned between the first charging rollers 17. The first charging roller 17 and the second charging roller 20 are made of, for example, a conductive rubber material.

  In this embodiment, the first charging unit 15 and the second charging unit 18 are formed to have a length that covers the width of the sheet, but may be formed to have a length that covers the entire width of the conveyance belt 9. good.

  The voltage applying unit 12 applies an alternating voltage to the first charging unit 15 and the second charging unit 18. In FIG. 2A, symbol Ds indicates the distance between the axes of the first charging unit 15 and the second charging unit 18, and in order to form a grid-like charging pattern as shown in FIG. The cycle of the alternating voltage or the distance Ds is set so that an integral multiple of the cycle of the alternating voltage applied by the voltage applying means 12 is equal to the distance Ds.

  As described above, in the present embodiment, the belt charging unit 14 includes the charging area in which the negative charging area En and the positive charging area Ep are arranged in a grid pattern on the conveyance belt 9 where the recording paper is placed. To form. As a result, even if floating ink droplets adhere to the recording paper due to the influence of the charged region, they are dispersed as a whole, making it difficult to visually recognize the adhesion of the ink droplets.

■■■ Second Example ■■■
Next, a second embodiment of the charging pattern formed by the belt charging means will be described with reference to FIGS. In the second embodiment, as shown in FIG. 3B, the loading area on which the recording paper is placed on the conveying belt 9 is formed in a charging area in which a minus charging area and a plus charging area are arranged in a grid pattern. It is characterized by doing. This is the same as the first embodiment described above, and this embodiment is different in the configuration of the charging unit that forms the grid-like charging pattern.

  As shown in FIG. 3A, the belt charging unit includes a charging unit 26 and a voltage applying unit 12A. The charging unit 26 has a charging roller 28 in contact with the conveyor belt 9 along a shaft 27 extending in a belt width direction (x direction) that is a first direction intersecting the moving direction (y direction) of the conveyor belt 9. It is arranged at intervals. The charging roller 28 includes a first region 28a to which a positive potential is applied along the circumferential direction, and a second region 28b that is electrically insulated from the first region 28a and to which a negative potential is applied. It is a complex consisting of The first area 28a and the second area 28b of the charging roller 28 are made of, for example, a conductive rubber material.

  The voltage applying unit 12A includes a direct current power source, and applies a voltage having a reverse polarity to each of the first region 28a and the second region 28b of the charging roller 28. As a result, a negative charging area En and a positive charging area Ep are alternately formed on the transport belt 9 along the belt moving direction by a single roller body. In addition, the adjacent charging roller 28 is attached to the shaft 27 so that the phases of the first region 28a and the second region 28b are reversed. As a result, even in the belt width direction, the negative charging region En The positive charging areas Ep are alternately formed, and a grid-like charging pattern is formed as described above.

■■■ Third Example ■■■
Next, a third embodiment of the charging pattern formed by the belt charging means will be described with reference to FIGS. 4 (A) and 4 (B). In the third embodiment, as shown in FIG. 4B, the loading area on which the recording paper is placed on the conveying belt 9 is arranged in a grid pattern in which a negatively charged area and an uncharged area (uncharged control area) are arranged. It forms in the charged area | region which consists of.

  FIG. 4B schematically shows such a charging pattern. An area indicated by reference numeral En is a negatively charged area (area where negative charges are generated), and an area indicated by reference numeral E0 (negatively charged area). (Region formed between En) indicates a non-charged region (non-charged control region).

  When a charged region extending in the paper width direction is viewed at an arbitrary position in the paper transport direction, the charged region Ck + 1 starts from the negatively charged region En and is directed to the right direction in the drawing in the non-charged region E0 and the negatively charged region En. , ... are alternately located. The next charged region Ck + 2 starts from the non-charged region E0 and is alternately positioned with the negatively charged region En, the non-charged region E0,.

  Further, when the charged region extending in the paper transport direction is seen at an arbitrary position in the paper width direction, the charged region Rk + 1 starts from the negatively charged region En, and the noncharged region E0 and the negatively charged region are directed upward in the figure. It is located alternately with the regions En,. The next charged region Rk + 2 starts from the non-charged region E0 and is positioned alternately with the negatively charged region En, the non-charged region E0,.

  As described above, in this embodiment, the belt charging unit forms the placement area on the conveying belt 9 where the recording paper is placed in a charging area in which the minus charging area En and the non-charging area E0 are arranged in a grid pattern. . As a result, even if the floating ink mist adheres to the recording paper due to the influence of the charged region, it is dispersed as a whole, making it difficult to visually recognize the adhesion of the ink mist.

  In this embodiment, no electric lines of force or electric force or Coulomb force are formed between the negatively charged region En and the non-charged region E0. However, the presence of the negatively charged region En causes static electricity due to dielectric polarization on the recording paper. The electroadsorption force acts, and the recording paper is adsorbed to the conveyance belt 9.

  The belt charging means for forming such a charging pattern includes a charging portion 29 and a voltage applying means 12B as shown in FIG. The charging unit 29 is configured such that a charging roller 31 in contact with the conveyance belt 9 is predetermined along an axis 30 extending in a belt width direction (x direction) that is a first direction intersecting a movement direction (y direction) of the conveyance belt 9. It is arranged at intervals.

  The charging roller 31 has a semicircular shape in which a half region in the circumferential direction is cut, and is made of, for example, a conductive rubber material. The adjacent charging roller 31 has a phase reversed by 180 °. And attached to the shaft 30.

  The voltage applying unit 12 </ b> B includes a DC power source and applies a negative voltage to the charging roller 31. As a result, a negatively charged region En and an uncharged region E0 are alternately formed on the transport belt 9 along the belt moving direction by one roller body. Also in the belt width direction, the negatively charged areas En and the non-charged areas E0 are alternately formed, and a grid-like charged pattern is formed as described above.

■■■ Fourth Example ■■■
Next, a fourth embodiment of the charging pattern formed by the belt charging means will be described with reference to FIG.
In FIG. 5, the display in which the characters “+” or “−” are circled is an image of the charging polarity (the polarity of the charge generated on the conveying belt) formed on the paper placing surface 9a of the conveying belt 9. It expresses. Reference numeral P1 indicates a recording sheet conveyed in advance, and reference numeral P2 indicates a recording sheet conveyed subsequent to the recording sheet P1.

  In this embodiment, as shown in FIG. 5, the placement area on which the recording paper is placed on the conveyance belt 9 is formed in a charging area in which a negative charging area and a positive charging area are arranged in a grid pattern. This is similar to the first and second embodiments described above. This embodiment is characterized by a charging pattern outside the paper placement area, that is, the area other than the paper placement area on which the recording paper is placed is negatively charged on the paper placement surface 9a. Thus, a charged state is formed by the belt charging means.

  Accordingly, the positively charged ink mist is attracted to and adhered to the negatively charged region outside the paper placement region of the transport belt 9. Thereby, it is possible to suppress the scattering of ink mist in the apparatus and to suppress or prevent various problems associated with the scattering of ink mist. In addition, the amount of ink mist adhering to the transport belt 9 can be increased, the amount of ink mist adhering to the recording surface of the recording paper can be reduced, and a better recording result can be obtained.

  Further, with the charging pattern as described above, the minus charge amount becomes more dominant than the plus charge amount with respect to the belt portion constituting the sheet placement surface 9a in the transport belt 9, that is, the minus charge amount is more than the plus charge amount. Therefore, the ink droplets (positively charged) drifting above the sheet placement surface 9a are effectively attracted to the conveying belt 9 side, and the scattering of the ink droplets can be further effectively suppressed. .

  The charging roller that forms such a charged state is configured as shown in FIG. 6, for example. The charged region width by the first charging unit 15 and the second charging unit 18 already described in FIG. 6 is formed to a length L1 (corresponding to the paper width).

On the other hand, the charging roller 33 is disposed in a region outside the length region L1 and is in contact with a region outside the paper region in the transport belt 9. A negative voltage is applied to the charging roller 33 by the voltage applying means 12C. As a result, a negative charging region is continuously formed in the conveyance belt 9 in the region in contact with the charging roller 33, that is, the region outside the sheet, along the sheet conveyance direction.
As described above, a charging pattern as shown in FIG.

  In forming a grid-like charging pattern by the charging pattern of the paper region, that is, the positive charging region and the negative charging region, a higher voltage may be applied when a negative voltage is applied than when a positive voltage is applied. The same applies to the first and second embodiments described above. As a result, the negative charge amount becomes more dominant than the positive charge amount, that is, the negative charge amount becomes larger than the positive charge amount, so that the ink droplets drifting above the sheet placement surface 9a (plus charge). Is effectively attracted to the side of the conveyor belt 9 and the scattering of ink droplets can be more effectively suppressed.

Each of the embodiments described above is an example, and it goes without saying that the present invention is not limited to these embodiments. In particular, in the present embodiment, the present invention is applied to an ink jet printer, but may be applied to other liquid ejecting apparatuses in general.
Here, the liquid ejecting apparatus uses an ink jet recording head, and is not limited to a recording apparatus such as a printer, a copier, and a facsimile machine that discharges ink from the recording head to perform recording on a recording medium. And a device for ejecting a liquid corresponding to the application from a liquid ejecting head corresponding to the ink jet recording head to an ejected medium corresponding to the recording medium, and attaching the liquid to the ejected medium.

  In addition to the recording head, as a liquid ejecting head, a color material ejecting head used for manufacturing a color filter such as a liquid crystal display, and an electrode material (conductive paste) used for forming an electrode such as an organic EL display or a surface emitting display (FED) Examples thereof include an ejection head, a bioorganic matter ejection head used for biochip production, and a sample ejection head as a precision pipette.

DESCRIPTION OF SYMBOLS 1 Inkjet printer, 2 Feed roller, 3 Inkjet recording head 4 1st paper detection sensor, 5 2nd paper detection sensor, 7 Drive roller, 8 Driven roller, 9 Conveyor belt, 10 Static elimination device, 11 Control part, 12, 12A- 12C Voltage application means, 14 Belt charging means, 15 First charging section, 16 shaft, 17 charging roller, 18 Second charging section, 19 axis, 20 charging roller, 22 Voltage applied member, 24 Cleaning roller, 26 Charging section, 27 axis, 28 charging roller, 29 charging unit, 30 axis, 31 charging roller, 33 charging roller, En negative charging area, Ep positive charging area, E0 non-charging area, P recording paper

Claims (8)

A conveying belt that is disposed at a position facing a recording head that performs recording by discharging droplets, and that attracts and conveys an object to be conveyed by electrostatic adsorption;
Belt charging means for charging the transport belt,
The belt charging unit applies a voltage for attracting the transported object to a placement area where the transported object is placed on the transport belt, and discharges an area excluding the mounting area on the transport belt. Applying only a voltage having a polarity different from that of the droplets to charge the transport belt,
A medium conveying apparatus characterized by the above. 2. The medium conveying device according to claim 1, wherein the belt charging unit discharges the liquid in an area located in a direction intersecting a conveying direction of the object to be conveyed among areas excluding the placement area. Charging to a voltage with a polarity different from that of the droplet,
A medium conveying apparatus characterized by the above. 3. The medium conveying device according to claim 1, wherein the belt charging unit includes the discharged liquid droplets in a region located in a conveyance direction of the object to be conveyed, in a region excluding the placement region. Is charged to a voltage of different polarity,
A medium conveying apparatus characterized by the above. The medium conveying apparatus according to any one of claims 1 to 3, wherein the belt charging unit forms the placement area in a charging area in which charging areas having different polarities are arranged.
A medium conveying apparatus characterized by the above. 5. The medium conveying apparatus according to claim 1, wherein the belt charging unit is configured to move along a first direction in which a first charging roller in contact with the conveying belt intersects a moving direction of the conveying belt. A first charging unit arranged at a predetermined interval;
The second charging roller that is located upstream of the first charging unit in the moving direction of the conveying belt and is in contact with the conveying belt is disposed between the first charging rollers along the first direction. A second charging unit comprising:
Voltage application means for applying an alternating voltage to the first charging unit and the second charging unit,
A medium conveying apparatus characterized by the above. 5. The medium conveying device according to claim 1, wherein the belt charging unit is electrically insulated from a first region to which a positive voltage is applied along a circumferential direction, and the first region. And a second region to which a negative voltage is applied, and the first region and the second region are alternately arranged along a first direction that intersects the moving direction of the transport belt. A charging unit having a charging roller;
Voltage application means comprising a direct current power source for applying a positive voltage to the first region and a negative voltage to the second region, respectively.
Charging a region excluding the front according depositing area negatively,
A medium conveying apparatus characterized by the above. The recording head;
The medium conveying device according to any one of claims 1 to 6,
Recording device. 8. The recording apparatus according to claim 7, wherein a voltage having the same polarity as that of the ejected liquid droplet is applied to a position downstream of the recording head in the medium conveyance path and facing the placement area. Comprising an application member,
A recording apparatus.

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