Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J13/00—Devices or arrangements of selective printing mechanisms, e.g. ink-jet printers or thermal printers, specially adapted for supporting or handling copy material in short lengths, e.g. sheets
  • B41J13/08—Conveyor bands or like feeding devices
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J3/00—Typewriters or selective printing or marking mechanisms characterised by the purpose for which they are constructed
  • B41J3/28—Typewriters or selective printing or marking mechanisms characterised by the purpose for which they are constructed for printing downwardly on flat surfaces, e.g. of books, drawings, boxes, envelopes, e.g. flat-bed ink-jet printers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
  • B65H5/00—Feeding articles separated from piles; Feeding articles to machines
  • B65H5/004—Feeding articles separated from piles; Feeding articles to machines using electrostatic force
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
  • B65H2404/00—Parts for transporting or guiding the handled material
  • B65H2404/20—Belts
  • B65H2404/22—Cross section profile
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
  • B65H2404/00—Parts for transporting or guiding the handled material
  • B65H2404/20—Belts
  • B65H2404/27—Belts material used

Definitions

• the present invention relates to a sheet conveying apparatus that conveys a sheet by electrostatic attraction, and in particular, is used in an image forming apparatus that forms an image by ejecting ink onto a sheet with a printing head.
• the present invention relates to an electrostatic attraction type sheet conveying apparatus capable of producing a great effect in a sheet conveying apparatus having a function of conveying along a print head while being held by a belt.
• a sheet means a sheet-like printing medium, for example, a printing paper, a film, a sheet-like material mounted in a roll shape, a cloth, or the like.
• the paper on which the ink has been transferred swells and causes cockling.
• the leading edge of the paper may float and collide with the print head on the transport path and cause a transport jam. Get higher.
• the sheet conveying means disclosed in Patent Document 1 is a pair of comb teeth that are nested together and connected to positive and negative potentials, respectively.
• the conveyor belt 10 2 made of a dielectric is moved above the electrodes 10 1, 1 0 1.
• the conveying belt 10 2 is polarized by the positively or negatively charged comb-like electrodes 1 0 0, 1 0 1 below it, and the surface thereof is charged, whereby the paper on the conveying belt 1 0 2 P can be adsorbed and transported.
• an electrode 20 2 is embedded inside the conveying belt 101.
• These electrodes 20 2 constitute a plurality of independent rectangular electrode groups whose longitudinal direction is the direction intersecting the conveying direction, and alternately arranged on the rain gutter portion of the conveying belt 20 1 in the conveying direction. So that the positive and negative brush-like charging members respectively disposed along both edges of the conveying belt 201 are alternately positively or negatively charged in the conveying direction. As a result, the sheet on the conveyor belt 210 can be sucked and conveyed.
• a charging roller 30 3 connected to an AC power source 30 is rotated on the lower surface of a conveying belt 30 1 made of an insulating material.
• the conveyor belt 3 0 1 is alternately positively or negatively charged in the conveyance direction, and the sheet on the conveyor belt 3 0 1 is sucked and conveyed by this. be able to.
• Patent Document 1 Japanese Patent Application Laid-Open No. 2000-090-3
• Patent Document I Japanese Patent Laid-Open No. 2 0 00 0-2 4 7 4 7 6
• Patent Document 3 Japanese Patent Laid-Open No. 2 0 0 3 _ 1 0 3 8 5 7
• the conveying belt 20 1 is wound around the roller, but the portion where the conveying belt 2 0 1 is bent by being hung around the roller
• the built-in electrode 20 2 itself does not bend
• the conveyor belt 2 0 1 is easily deteriorated due to a large load.
• the movement of the conveyor belt 20 1 becomes intermittent for the same reason as pointed out in the technique described in Patent Document 1.
• the conveying belt 101 since the conveying belt 101 has a structure in which the electrode 20 2 is incorporated, the thickness of the conveying belt 20 1 is relatively larger than that of the sheet conveying means of other structures.
• the present invention has been made in view of the above problems, and is a sheet conveying apparatus that conveys a sheet by electrostatic attraction, and more particularly, an image forming apparatus that forms an image by ejecting ink onto a sheet with a printing head
• a sheet transport device that is electrostatically attracted to a belt and transports along a print head, and can realize a stable suction force and transport speed with a simple structure and is less susceptible to humidity.
• An object of the present invention is to provide a sheet transport device that hardly generates ink droplet bending due to the influence of an electric field. Disclosure of the invention
• a first potential is applied, and a dielectric layer is provided on a surface on the side where the sheet is conveyed.
• a fixed electrode provided, and conveyance of the sheet relative to the dielectric layer of the fixed electrode. 7 069786
• the sheet is driven on the surface opposite to the fixed electrode side by forming a plurality of through-holes through which the electric force lines from the fixed electrode pass, and being driven by circulating in 5 directions.
• a transport belt made of a conductive material that is electrostatically attracted.
• the sheet conveying device described in claim 2 is provided in an image forming apparatus that forms an image on a sheet by ejecting ink from a plurality of print heads arranged at intervals to the sheet, In a sheet conveying apparatus that conveys a sheet along a print head, the sheet is disposed below the print head, is provided with a first potential, and a dielectric layer is provided on the surface of the print head.
• the fixed electrode provided and the dielectric layer of the fixed electrode are driven to circulate in a single conveying direction so as to be supplied with a second potential, and the electric lines of force from the fixed electrode penetrate therethrough.
• a conveying belt made of a conductor in which a plurality of through holes are formed and a sheet is electrostatically adsorbed on the surface of the printing head.
• the first potential and the second potential mean two different potentials in which a potential difference is recognized between them. For example, if the first potential is a positive potential, the second potential is 0 or a negative potential, and if the first potential is 0 or a negative potential, the second potential is a positive potential. is there.
• the first potential is +3 V and the second potential is + It may be 1 V, or the first potential may be 13 V and the second potential may be 15 V.
• the sheet conveying apparatus described in claim 3 is the sheet conveying apparatus according to claim 1 or 2, wherein the fixed electrode is divided into a plurality of lines and arranged in the sheet conveying direction. It is characterized by being.
• the sheet conveying device according to claim 4 is a sheet conveying device according to claim 3.
• each of the fixed electrodes divided into a plurality is arranged at a position not opposite to each of the print heads.
• the sheet conveying apparatus described in claim 5 is the sheet conveying apparatus according to any one of claims 1 to 4, wherein the sheet of the conveying belt is placed on the sheet conveying apparatus.
• a dielectric layer is provided on the surface, and a plurality of openings communicating with the respective through holes are formed in the dielectric layer.
• the sheet conveying apparatus is the sheet conveying apparatus according to any one of claims 1 to 4, wherein the sheet on the side of the conveying belt on which the sheet is placed.
• a dielectric layer is provided, and an opening is formed in the dielectric layer so as to communicate with a part of the plurality of through holes formed in the transport belt.
• the sheet conveying device is the sheet conveying device according to any one of claims 2 to 6, wherein the sheet conveying device is disposed downstream of the conveying belt in the sheet conveying direction.
• a discharge roller that is provided adjacently and discharges downstream at a speed greater than the conveying belt while adsorbing the image-formed sheet; and the printing head and the discharge roller that are downstream in the sheet conveying direction Electrostatic discharge force that is stronger than the suction force of the discharge roller when the sheet is applied to the rain of the print head and the discharge roller that are provided on the most downstream side in the sheet conveyance direction. And an adsorption electrode.
• the sheet conveying device is provided in an image forming apparatus that forms an image on a sheet by ejecting ink from the printing head to the sheet, and in a state where the sheet is electrostatically adsorbed.
• a conveying belt that conveys the sheet by moving along the printing head; and provided adjacent to the downstream side of the conveying belt in the sheet conveying direction.
• a sheet conveying apparatus having a discharge roller for discharging the formed sheet downstream at a speed higher than that of the conveyance belt while adsorbing the formed sheet, and the printing head and the discharge roller at the most downstream in the sheet conveyance direction.
• an electrostatic adsorption force stronger than the adsorption force of the discharge port roller is provided. It is characterized by the fact that an electrostatic chucking electrode is provided.
• the first potential when the first potential is a positive potential and the second potential is 0 or a negative potential, the first potential is fixed.
• the electrode polarizes the dielectric layer and generates a positive charge on its surface, and the lines of electric force generated thereby pass through the hole in the conveying belt to which the second potential is applied. Passing through and passing through the sheet placed on the surface of the conveyor bell ⁇ , it polarizes this, creating positive and negative charges on its front and back surfaces, so the part of the through hole in the range adjacent to the fixed electrode of the conveyor belt Alternatively, the sheet is electrostatically attracted to the transport belt in the vicinity thereof. If the transport belt is moved along the fixed electrode, the sheet is transported while being electrostatically attracted to the transport belt.
• the first potential is a positive potential and the second potential is 0 or a negative potential
• the first potential is fixed.
• the electrode polarizes the dielectric layer and generates a positive charge on its surface, and the electric lines of force thereby pass through the through hole of the carrier bell to which the second potential is applied, which is directly above the fixed electrode.
• the sheet Through the hole, it reaches the sheet placed on the surface of the conveyor bell ⁇ , polarizes it, and has positive and negative charges on its front and back surfaces. Therefore, the sheet is electrostatically adsorbed to the conveyance belt at or around the through-hole portion in the range adjacent to the fixed electrode of the conveyance belt. If the transport belt is moved along the fixed electrode, the sheet is transported while being electrostatically attracted to the transport belt.
• the sheet is conveyed by moving the conveyance belt that adsorbs the sheet while being adsorbed to the fixed electrode, so the distance between the print head and the sheet can be kept constant, This improves the printing quality.
• the electrode is divided in the sheet conveying direction. There is an effect that the transport load is reduced.
• each of the fixed electrodes divided into a plurality of relative positions is relative to each printing head.
• the ink droplets ejected from the print head are not affected by the electric field generated by the fixed electrode, so that the flight bend does not occur.
• the conveyor belt as a movable electrode of the second potential moves with respect to the fixed electrode of the first potential. Since each electrode is independent, the comb-like electrode in terms of assemblability and manufacturing cost This is advantageous as compared with a conventional electrostatic attraction type sheet conveying apparatus using the like.
• the positive and negative electrodes are arranged in a vertical relationship, making it easier to set the distance between the two electrodes that determine the attractive force more easily and precisely.
• a voltage can be applied to the fixed electrode by ordinary wiring connection, and a voltage can be applied to the conductive conveyance belt, which is a movable electrode, for example, by a roller connected to a predetermined potential.
• the thickness of the transport belt itself is larger than that of a conventional electrostatic adsorption transport device that incorporates an electrode in the transport belt. Since the surface roughness is small and the unevenness on the surface is small, it is possible to reduce the uneven thickness, reduce the uneven transport speed, and obtain a good print image quality.
• the dielectric layer polarized by the fixed electrode at the first potential passes through the through hole of the transfer bell ⁇ ⁇ to which the second potential is applied, directly above the fixed electrode and the opening of the dielectric that communicates with the transfer belt. It reaches and penetrates the sheet placed on the surface of the belt and polarizes it, and reaches and penetrates the dielectric layer of the transport belt to polarize it, and the opposite sides of the sheet and dielectric layer are opposite to each other. Therefore, the sheet is surely electrostatically adsorbed to the dielectric layer of the conveyor belt at and around the through hole in the area adjacent to the fixed electrode of the conveyor belt. It is.
• the through hole of the conveying belt and the dielectric layer In the part where the opening communicates the electric lines of force from the positive charge on the surface of the dielectric layer polarized by the fixed electrode at the first potential are not generated in the through hole of the conveying belt to which the second potential is applied.
• the through hole directly above the fixed electrode and the opening of the dielectric layer communicating with the through hole reach the sheet placed on the surface of the conveyor belt and polarize it, and the dielectric layer of the conveyor belt. And penetrates and polarizes the sheet and the dielectric layer to generate positive and negative charges opposite to each other on the front and back surfaces of the sheet and the dielectric layer.
• the sheet is reliably electrostatically absorbed by the dielectric layer of the conveyor belt. Worn.
• the electric field lines from the positive charges on the surface of the dielectric layer polarized by the fixed electrode at the first potential are Among the given through holes of the conveyor belt, it penetrates the through hole directly above the fixed electrode and the dielectric layer blocking it, reaches the sheet placed on the surface of the conveyor belt, and splits it. At the same time, it reaches and penetrates the dielectric layer of the conveyor belt and polarizes it, generating positive and negative charges opposite to each other on the front and back surfaces of the sheet and the dielectric layer, adjacent to the fixed electrode of the conveyor belt
• the sheet is electrostatically adsorbed to the conveying belt around the through-holes.
• the same charge as that of the dielectric layer of the conveyor belt is accumulated in the portion of the dielectric layer of the conveyor belt where the through holes are blocked, and this has passed through the sheet.
• the field lines are cut off, and no charge is formed on the front and back surfaces of the sheet, and the attractive force of the sheet to the dielectric layer decreases.
• the transport belt communicates with the opening formed in the dielectric layer. If the holes penetrating vertically and the holes blocked by the dielectric layer are formed with an appropriate distribution, in the adsorption range by the conveyor belt, the adsorption force is maintained and the attenuation part Can be arranged in any proportion or distribution. For this reason, when conveying a sheet using a conveyance belt that uses electrostatic adsorption, the sheet can be securely held in the adsorption range of the conveyance belt with a strong adsorption force at the start of sheet adsorption, and is necessary for conveyance during sheet conveyance.
• the extra attractive force can be attenuated over time while leaving a strong attractive force, so the ink droplets ejected from the print head toward the sheet can be bent by the influence of the electric charge. This eliminates some inconveniences and improves image reproducibility, and when the sheet is discharged from the last print head in the transport direction due to movement of the transport belt, the sheet is discharged.
• the adsorbing force at the trailing edge of the sheet is quickly attenuated to improve the separation property (peelability from the conveyor belt) when discharging the sheet, and the sheet can be discharged smoothly from the conveyor belt to the front. , Sheet alignment property after the discharge is improved.
• the fixed electrode is composed of a plurality of divided parts
• the charged state of the sheet is quickly eliminated at the position of the print head between the fixed electrode and the print head.
• Ink droplets ejected from the sheet toward the sheet can be bent due to the influence of electric charges.
• the inconvenience is effectively eliminated, and the reproducibility of the image is improved.
• sheet alignment on the delivery table due to sheet charging during delivery is reduced.
• the sheet conveying device described in claim 7 in the effect of the sheet conveying device according to any one of claims 2 to 6, the sheet is advanced by the discharge port roller. Therefore, it is possible to prevent the occurrence of print quality degradation such as color misregistration.
• the sheet conveying apparatus described in claim 8 the sheet is electrostatically attracted and conveyed, and the ink is ejected by the printing head to form an image.
• the sheet is discharged at high speed, the sheet is placed on both the print head and the discharge roller at the most downstream in the sheet conveyance direction, and in the state where printing is continued, it is provided at this position.
• the electrostatic chucking electrode holds the sheet with an electrostatic chucking force that is stronger than the suction force of the discharge roller. It does not occur, and deterioration of printing quality such as color shift is prevented.
• FIG. 1 is an overall configuration diagram of a first embodiment of the present invention.
• FIG. 2 is a cross-sectional view showing the charged state of each member in the vicinity of the conveyor belt of the first embodiment.
• FIG. 3 is a cross-sectional view showing the charged state of each member in the vicinity of the conveyor belt of the second embodiment.
• FIG. 4 is a cross-sectional view showing the charged state of each member in the vicinity of the conveyor belt of the second embodiment.
• FIG. 5 is an overall configuration diagram of the third embodiment of the present invention.
• FIG. 6 is a perspective view showing an adsorption area of the conveyance belt in the vicinity of the conveyance belt of the third embodiment.
• FIG. 7 is an overall configuration diagram of a modified example of the third embodiment of the present invention.
• FIG. 8 is an overall configuration diagram of the fourth embodiment of the present invention.
• FIG. 9 is an overall configuration diagram of a modified example of the fifth embodiment of the present invention.
• FIG. 10 is a schematic perspective view of the electrostatic adsorption electrode of the sixth embodiment.
• FIG. 11 is an overall configuration diagram of a seventh embodiment of the present invention.
• FIG. 12 is an overall configuration diagram of a modified example of the eighth embodiment of the present invention.
• FIG. 13 is a plan view of a comb electrode used in a conventional electrostatic conveyance type sheet conveying apparatus.
• FIG. 14 is a cross-sectional view showing the charged state of each member in the vicinity of the conveying belt in an electrostatic conveying type sheet conveying apparatus using a conventional comb electrode.
• FIG. 15 is a front view of a conventional electrostatic conveyance type sheet conveying apparatus with a built-in electrode. It is a front view of the conventional electrostatic conveyance type sheet conveying apparatus with a built-in electrode.
• FIG. 16 is a cross-sectional view of a conveying belt in a conventional electrostatic conveying sheet conveying apparatus with a built-in electrode.
• FIG. 17 is a cross-sectional view of the vicinity of the conveying belt in the conventional charging roller type electrostatic conveying sheet conveying apparatus.
• the image forming apparatus 2a of the first example has a plurality of print heads 3 with different ink colors 3 facing downwards at predetermined intervals along the conveying direction of the sheet S indicated by the arrows.
• the ink droplets are ejected toward the sheet S conveyed below.
• four printing heads 3 are installed to eject four color inks of C (cyan), K (black), M (magenta evening), and Y (yellow), respectively.
• a sheet conveying device 1 a for conveying the sheet S along the print head 3 is disposed immediately below the print heads 3.
• a registration roller 4 and a driven roller 5 are provided adjacent to a sheet feeding mechanism (not shown) on the front side of the printing head 3 in the conveyance direction, and the sheet S is supplied to the next sheet conveyance device 1a.
• the sheet conveying apparatus 1a includes a driven roller 6 on the upstream side in the conveying direction, a driving port 8 provided downstream in the conveying direction and linked to the driving source 7, and a middle between the driven roller 6 and the driving roller 8.
• An endless conveyance belt 10 is wound around the tension roller 9 disposed below, and the conveyance belt 10 is conveyed by the driving roller 8 while applying appropriate tension to the conveyance belt 10 by the tension roller 9 biased downward. It is configured to be able to circulate and move 10 in the transport direction.
• the inner side of the conveyor belt 10 (the side in contact with the driven roller 6) is conductive. It consists of a body 11 and has a two-layer structure with a dielectric layer 12 on the outside (the side facing the printing head 3).
• the dielectric 12 has a dielectric property superior to the electrical conductivity, and has a dielectric property against a direct current, such as plastic.
• the conductor 11 and the dielectric layer 12 are formed with a plurality of circular holes with the same inner diameter that pass through continuously at appropriate intervals. As will be described later, these through holes are formed to form an electric field in and around the sheet S on the transport belt 10. Here, for convenience, the holes of the conductor 11 are formed.
• the through hole 13 and the hole of the dielectric layer 12 that communicates with the through hole 13 are referred to as an opening 14.
• the driven roller 6 has at least a peripheral surface having conductivity, and a zero or negative potential is applied to the peripheral surface by the voltage application unit 36 controlled by the control unit 38.
• the conductor 11 of the conveyor belt 10 that is in metal contact with this is set to 0 (ground) or a negative potential. That is, the conveyance belt 10 of the first example is a movable electrode having 0 or a negative potential.
• a rectangular plate-like platen base 15 a that supports the conveyance belt 10 is installed below the conveyance belt 10 in the conveyance path of the sheet S.
• the platen base 15 a is made of an insulator, and a fixed electrode 16 a which is a single plate electrode connected to the charge applying unit 36 and applied with a positive potential is embedded therein.
• the fixed electrode 16a is arranged below the print head 3 so as to occupy a range including the four print heads 3 in a plan view.
• the surface of the fixed electrode 16a (the side facing the conveyor belt 10) has a dielectric layer 17 to prevent short circuit due to contact with the conveyor belt 10 moving along the surface. Is provided.
• the dielectric layer 17 is polarized by the fixed electrode 16a and the surface thereof becomes a positive potential, the electric lines of force from the fixed electrode 16a side are conveyed belts directly above the fixed electrode 16a. 10 Passes through the through hole (through hole 1 3 and opening 14) and goes above the conveyor belt 10 and passes through the sheet S placed on the surface of the conveyor belt 10 from below. Is further bent downward and passes through the sheet S from above at the periphery of the hole of the conveyor belt 10 to polarize it to the opposite potential. Further, the dielectric layer 1 2 of the conveyor belt 10 This reaches and penetrates and polarizes this.
• the suction region in the transport belt 10 that can adsorb the sheet S is only a portion having substantially the same shape or range as the fixed electrode 16 a directly above the fixed electrode 16 a.
• the adsorption region is generated at a position directly above the fixed electrode 16a in the transport belt 10 passing immediately above the fixed electrode 16a.
• the sheet S is supplied to the conveying belt 10 driven by the driving roller 8, and the sheet S is conveyed along the conveying direction while being sucked and held by the conveying belt 10, and is adjusted to the conveying speed.
• a desired color image can be formed on the sheet S by driving each printing head 3 at an appropriate timing and ejecting ink droplets of each color onto the sheet S.
• the conveying belt 10 which is a movable electrode having 0 or a negative potential with respect to the fixed electrode 16 a having the positive potential is provided. Because of the simple structure of moving, comb-shaped electrodes are used in terms of assembly and manufacturing cost. This is more advantageous than the conventional electrostatic adsorption type sheet conveying apparatus 1.
• the positive and negative electrodes are arranged in an up-down relationship, making it easier to set the distance between the two electrodes that determine the attractive force more easily and precisely.
• a fixed electrode 16 a that is a flat plate-like electrode is arranged below the plurality of printing heads 3, and the conveying belt 10 that adsorbs the sheet S is located below the printing head 3. Since the sheet is transported by moving while maintaining the state adsorbed to the fixed electrode 16a, printing is performed within the range of the fixed electrode 16a where the printing head 3 is disposed. The distance between the head and the sheet can be kept constant, which improves printing quality. Also, one type of positive and negative electrodes is divided into a fixed electrode 16a and a conveyor belt 10 as a movable electrode.
• Each of the positive and negative of the conveyor belt 10 polarized according to the potential of the comb-like electrode like a conventional electrostatic conveyance device with comb-like electrodes charged alternately positive and negative
• the charged part is transported instantaneously relative to the adjacent comb-like electrode of the opposite potential by movement. No inconvenience would resistance is caused, because the conveyed without become intermittent, it is possible to convey the sheet S in a smooth operation, it is possible to obtain good print quality.
• the thickness of the conveyor belt 10 itself is smaller and the unevenness of the surface is less than that of a conventional electrostatic adsorption type conveyor device that incorporates electrodes in the conveyor belt 10. Therefore, uneven thickness can be reduced. Yes, it is possible to reduce unevenness in the conveyance speed and to obtain good print image quality in this respect.
• the dielectric layer 12 is provided on the surface of the conveyor belt 10, the user accidentally touches the conductor 11 of the conveyor belt 10 during use or inspection, etc. Accidents can be prevented and it is safe. Note that there is no dielectric layer 1 2 on the conveyor belt 10 W
• the sheet S and the dielectric layer 17 of the fixed electrode 16 a facing the sheet S are polarized at opposite potentials. The suction force is ensured, and the sheet S can be sucked onto the conveyor belt 10.
• holes are passed through the conveyor belt 10, but the holes are made of polyacetylene, polyparaphenylene, polyaniline, polythiophene, polypyrrole, polyacene.
• a conductive polymer such as polyparaphenylene vinylene may be used.
• the sheet conveying apparatus of the second example is installed in the same image forming apparatus as the image forming apparatus 2a of the first example, and the basic principle of electrostatic adsorption is the same as that of the first example.
• the description of the forming apparatus and the common part of the electrostatic attraction mechanism will be omitted, and the structure of the transport belt 20 different from the first example will be mainly described.
• the through holes 1 3 of the conductor 1 1 and the openings 14 of the dielectric layer 1 2 communicate with each other at all points, that is, all the holes of the conveying belt 10 are completely It was in the state which penetrated.
• the second example as shown in FIG. 3, there is a portion in which no opening is formed in the dielectric layer 12 with respect to the through hole 13 of the conductor 11. A part of the 10 hole is completely penetrated, but a part of the 10 hole is covered with the dielectric layer 12 having the opening 13 but not having the opening 14 so as not to penetrate.
• the same principle as explained in the first example is used.
• the sheet S is adsorbed to the conveyance belt 20.
• the electrostatic attraction force is There is a phenomenon that decreases with the passage of time.
• the sheet S can be securely held within the adsorption range of the conveyor belt 20 by force, and while the sheet S is being conveyed, the excess adsorption force is attenuated over time while leaving the adsorption force necessary for conveyance. Therefore, it is possible to improve the image reproducibility by eliminating the inconvenience that the ink droplets ejected from the print head toward the sheet bend the path due to the influence of the electric charge.
• the sheet conveying apparatus 1b of the third example is provided in the same image forming apparatus 2b as the image forming apparatus 2a of the first example, and the basic principle of electrostatic adsorption is the same as that of the first example. Therefore, the description of the image forming apparatus 2b and the common part of the electrostatic attraction mechanism will be omitted, and the structure of the fixed electrode 16b different from the first example will be mainly described.
• a rectangular plate-like platen base 15 b that supports the conveyance belt 10 is installed below the conveyance belt 10 in the conveyance path of the sheet S.
• This platen base 15 b is made of an insulator, and is connected to the charge application section 36 and a plurality of fixed electrodes 16 b (five in the third example) to which a positive potential is applied are spaced at a predetermined interval. Embedded.
• the fixed electrode 16 b is located at a position not facing the print head 3, specifically, a position in front of the print head 3 (C) that is most upstream in the transport direction, and four print heads.
• each fixed electrode 16 (the side facing the conveyor belt 10) has a dielectric layer 1 in order to prevent a short circuit due to contact with the conveyor belt 10 moving along the surface. 7 is provided.
• the suction region ⁇ ⁇ ⁇ on the conveying belt 10 where the sheet S can be sucked is fixed electrode 1 6 directly above fixed electrode 1 6 b. Therefore, this adsorption region H is located at a position directly above the fixed electrode 16 b in the conveyor belt 10 passing immediately above each fixed electrode 16 b. It occurs at substantially the same arrangement interval as the fixed electrode 16b.
• the fixed electrode 16 b is a divided structure composed of a plurality of spaced electrodes. Single plate-like solid Compared to the constant electrode 16 a, the area where the resistance is generated by contact and adsorption with the moving belt 10 is small, so that the transport load is more advantageous than the first example.
• each printing head 3 is arranged avoiding the position of the fixed electrode 16 b, and there is no fixed electrode 16 b under the printing head 3, and there is no downward direction from each printing head 3. Ink droplets are less likely to be bent due to the electric field of the fixed electrode 16 b.
• the charged state of the sheet S is more quickly eliminated, so the print head 3 is directed to the sheet S.
• the inconvenience that the ejected ink droplet is bent due to the influence of the electric charge can be more reliably eliminated, and the deterioration of the sheet alignment on the paper discharge table due to the charging of the sheet S can be more reliably reduced during the paper discharge.
• FIG. 7 is an overall structural diagram showing a modification of the third example.
• the structure of the image forming apparatus 2b having the sheet conveying apparatus 1b of the present modification is that the charge applying section 36 gives 0 or a negative potential to the driven roller 6, and the image recording medium to be conveyed It differs from the third example in that the body is not a sheet but a roll sheet S ′, and the other points are the same as in the third example.
• the body is not a sheet but a roll sheet S ′, and the other points are the same as in the third example.
• sheet-like printing media such as printing paper and film, but also sheet-like objects mounted in a roll shape are continuously conveyed to form a high-quality image. It can also be done.
• the registration roller 4 and the driven roller 5 are omitted.
• the discharge roller 40 that adsorbs the sheet S on which the image has been formed and discharges it downstream. It has been.
• the discharge roller 40 rotates at a speed higher than that of the transport belt 10 to improve the discharge performance, and is always driven during image formation performed by the print head 3 while transporting the sheet S. ing.
• the suction force at the discharge roller 40 is the suction fan 41 provided below the discharge roller 40, and the suction force by the suction (wind) is larger than the suction force by the conveying belt 10 alone. .
• the sheet conveying apparatus 1c of the present example has a reduced size in the sheet conveying direction including the discharge roller 40, and the print head 3 (Y) that is the most downstream in the sheet conveying direction and the discharge
• the roller 40 has a compact configuration in which the distance between the sheets S is shorter than the length of the sheet S in the conveying direction.
• a compact configuration is preferable in various respects, when the most downstream printing head 3 (Y) forms an image on the rear end portion of the sheet S, the leading end portion of the sheet S is formed. Is applied to the constantly driven discharge roller 40 and receives its driving force, so if no treatment is required, the discharge roller 40 will remove the sheet S during image formation in the most downstream printing head 3 (Y). Pulling may cause color shift.
• the electrostatic adsorption electrode 50a is provided between the printing head 3 (Y) and the discharge roller 40 which are in the lowermost stream in the conveying direction of the sheet S. If the sheet S is in the rain of the print head 3 (Y) and the discharge roller 40 at the most downstream position, the sheet S is pressed by the electrostatic adsorption electrode 50 a, and the sheet S is discharged. It is configured not to cause color misregistration when pulled in the direction.
• the electrostatic adsorption electrode 50 a is an electrode provided on the platen base 15 b together with the fixed electrode 16 b described above, but is structurally and electrically independent from the fixed electrode 16 b.
• a positive potential higher than that of the fixed electrode 16 b is applied by the charge applying unit 36, thereby generating an electric field stronger than the electric field generated by the fixed electrode 16 b, and thus the sheet being imaged.
• the suction force to the conveyor belt 10 at the rear end of S is increased.
• the driving roller 8 is rotated by the drive source 7 to circulate and move the conveyance belt 10 in the conveyance direction. Then, the sheet S electrostatically attracted onto the conveying belt 10 by the electric field generated by the fixed electrode 16 b is conveyed along the printing heads 3 below the printing heads 3. To go. A desired image can be formed on the sheet S by driving each printing head 3 in synchronization with the conveyance of the sheet S by the conveyance belt 10.
• the trailing edge of the sheet S is affected by the electric field generated by the electrostatic adsorption electrode 50a provided adjacent to the downstream of the downstreammost print head 3 (Y) in the sheet conveyance direction, and the conveyance bell
• the sheet S is not pulled by the discharge roller 40 and is not displaced in the discharge direction, and there is no color in the most downstream print head 3 (Y). There is no danger of this inconvenience.
• the suction force on the conveying belt 10 side always exceeds the suction force on the discharge roller 40.
• the suction force of the sheet S generated on the transport belt 10 by the electrostatic suction electrode 50 a may be always larger than the suction force at the discharge outlet 40, and the sheet S is the most downstream print. It may be increased only at the timing applied to the head 3 (Y) and the discharge roller 40. Further, in the control of the electrostatic adsorption electrode 50 a, the control unit 38 and the charge application unit 36 determine that the sheet S has escaped from the most downstream print head 3 (Y), for example, a paper leading edge detection sensor. It is also possible to vary the attraction force of the electrostatic attraction electrode 50 a by detecting it from the detection signal and the number of encoder pulses.
• the distance between the final print head 3 and the discharge roller 40 must be longer than the sheet S so that the sheet conveyance speed during image formation is not affected by the speed of the discharge roller 40. It was getting bigger.
• the discharge speed of the discharge roller 40 is set to be lower than the speed of the conveyor belt 35 so that color misregistration does not occur.
• FIG. 9 shows a sheet conveying device 1 a (see FIG. 1) having a fixed electrode 16 a in the first example, and a sheet conveying device 1 c (see FIG. 8) in the fourth example.
• This is a combination of adsorption electrodes 50a.
• the components corresponding to the functions or names are given the above-mentioned symbols, and the above explanations (configuration, action, effect, etc.) are used. .
• the sheet conveying apparatus of the sixth example is different from the fourth example and the fifth example only in the structure of the electrostatic chucking electrode, and the other configurations are the same. Therefore, only the electrostatic chucking electrode part is shown and described.
• the electrostatic adsorption electrode 50 0 a is a single rectangular electrode provided under the conveyor belt 35 and applied with a positive potential.
• the electrostatic attraction electrode 60 has a comb-like shape provided at substantially the same position as the electrostatic attraction electrode 50 a in the fourth and fifth examples. Electrode. In this comb electrode, adjacent comb teeth 61 and 62 are alternately connected to a positive or negative (or 0) potential and are insulated from each other. Also in this example, the same effect as the fourth example and the fifth example can be obtained.
• the sheet is pulled in the discharge direction so that color misregistration does not occur by making the suction force of the trailing edge of the sheet stronger than the suction force of the discharge roller.
• the technology of the sheet conveying apparatus configured as described above can be effectively applied to, for example, a general electrostatic conveying apparatus as described in “Background Art”. So, 7th
• an electrostatic chucking electrode that sucks the trailing edge of the sheet with a stronger suction force than the suction force of the discharge roller was installed. An example will be described.
• the sheet conveying device 30 includes a driven port roller 31 connected to 0 or a negative potential on the upstream side in the conveying direction, and a driving roller 3 3 provided on the downstream side in the conveying direction and linked to the driving source 32. Then, an endless conveyance belt 35 made of a dielectric is wound around a tension roller 3 4 disposed below the intermediate position between the driven roller 31 and the driving roller 33.
• a charging roller 37 that is connected to the charge application unit 36 and has a positive potential is provided on the outer surface side of the conveyor belt 35 that is wound around the driven roller 31 .
• a conveying belt 35 is sandwiched between the connected driven roller 3 1 which is connected to the counter electrode.
• the charge application unit 36 is connected to the control unit 38, and is controlled by the control unit 38 so that a desired positive potential can be applied to the electrode member to be connected.
• the core of the charging roller 37 is made of metal, and the surface thereof is formed of, for example, a rubber material having a resistivity of about 1 ⁇ 10 12 ⁇ to generate friction necessary for conveyance.
• the conveyor belt 35 is made of a dielectric material as described above.
• the dielectric is a substance that can be charged by itself and adsorb the charged object (sheet S).
• sheet S the charged object
• a polyimide film of about 1 X 10 1 2 to 1 X 1 0 " ⁇ is used.
• the conveying belt 35 is negatively charged on the front surface (upper side) in the conveying path (the upper portion of the circulating belt) that adsorbs the sheet S. (Lower) is positively charged. If a sheet S such as printing paper, which is a printing medium, is supplied onto the conveyor belt 35, the side that contacts the conveyor belt 35 (lower surface) is positive and the front side (upper surface) is negative. Each is polarized and charged and electrostatically attracted to the conveyor belt 35.
• a sheet S such as printing paper, which is a printing medium
• the driving roller 33 is driven while an appropriate tension is applied to the conveyor belt 35 by the tension roller 34 biased downward. If the conveyor belt 35 is circulated and moved in the conveyance direction by being rotated by the source 32, the sheet S electrostatically adsorbed on the conveyor belt 35 is placed under the print head 3 in each print head. Can be transported along That is, the portion of the conveyor belt 35 that moves around these rollers and moves horizontally adjacent to the print head 3 is the conveyance path of the sheet S.
• a rectangular plate-like platen base 15 that supports the conveyor belt 35 is installed below the conveyor belt 35 in the sheet S conveyance path.
• the platen base 15 is made of an insulator and has a role of supporting the conveyor belt 35.
• a discharge roller 40 that adsorbs the sheet S on which an image has been formed and discharges it downstream is provided adjacently.
• the discharge roller 40 rotates at a higher speed than the conveying belt 35 in order to improve the discharge performance, and is always driven during image formation performed by the printing head 3 while conveying the sheet S. ing.
• the suction force at the discharge roller 40 is the suction fan 41 provided below the discharge roller 40.
• the suction force by the suction (wind) is more than the suction force by the conveyor belt 35 alone. Is also big.
• the sheet conveying apparatus 30 of this example is arranged in the sheet conveying direction including the discharge roller 40.
• the size is reduced, and the distance between the print head 3 (Y) located downstream in the sheet conveyance direction and the discharge roller 40 is shorter than the length of the sheet S in the conveyance direction.
• a compact configuration is preferable in various points, but when the most downstream printing head 3 (Y) forms an image on the rear end of the sheet S, the front end of the sheet S is always driven. Since the driving force is applied to the discharge roller 40, if there is no need for any treatment, the discharge roller 40 pulls the sheet S during image formation at the most downstream print head 3 (Y), causing color misregistration. May occur.
• the electrostatic adsorption electrode 5 Ob is provided between the printing head 3 (Y) and the discharge roller 40 which are in the lowermost stream in the conveying direction of the sheet S. If the sheet S is on both the most downstream printing head 3 (Y) and the discharge roller 40, the sheet S is pressed by the electrostatic adsorption electrode 50b. It is configured not to cause color misregistration when pulled in the discharge direction.
• the electrostatic adsorption electrode 50 b does not contact the conveying belt 35 at the upper and lower positions between the most downstream printing head 3 (Y) and the discharge roller 40 with the conveying belt 35 interposed therebetween.
• the positive electrode plate 5 1 (upper side) and the negative electrode plate 5 2 (lower side) are arranged in such a way that the sheet S is attracted to the conveyor belt 35 by the electric field generated between the rain electrode plates 51 and 52. It is designed to increase power.
• the driving roller 33 is rotated by the drive source 32 and the conveyance belt 35 is circulated in the conveyance direction.
• the sheet S electrostatically attracted onto the conveyor belt 35 is conveyed along the print heads 3 below the print heads 3.
• each print head 3 is driven in synchronization with the conveyance of the sheet S by the conveyance belt 35. Then, a desired image can be formed on the sheet S.
• the leading end portion of the sheet S is already applied to the discharge roller 40, and the suction force causes the discharge roller. While being attracted to 40, it is pulled in the discharge direction at a speed higher than that of the conveyor belt 35.
• the substantially middle portion of the sheet S is affected by the electric field between the most downstream printing head 3 (Y) and the discharge roller 40 by the electrostatic adsorption electrode 50b, and the surface of the conveyor belt 35 Therefore, the sheet S is not pulled in the discharge direction by being pulled by the discharge roller 40, and the inconvenience of color misregistration occurs in the most downstream print head 3 (Y). There is no fear.
• the suction force on the conveying belt 35 side always exceeds the suction force on the discharge roller 40.
• the suction force of the sheet S on the conveyor belt 35 may be always larger than the suction force of the discharge roller 40 by the electrostatic suction electrode 5.0 b, or the sheet S may be at the most downstream printing head. It may be increased only at the timing applied to the cylinder 3 (Y) and the discharge roller 40. Further, in the control of the electrostatic adsorption electrode 5 Ob, the control unit 3 8 and the charge application unit 3 6 detect that the sheet S has gained from the most downstream print head 3 (Y), for example, the front end of the paper Electrostatic adsorption electrode 5 is detected by detecting from the detection signal from the sensor and the number of encoder pulses. The adsorption force of 0 b may be varied.
• the distance between the final print head 3 and the discharge roller 40 must be longer than the sheet S so that the sheet conveyance speed during image formation is not affected by the speed of the discharge roller 40. It was getting bigger.
• the discharge speed of the discharge roller 40 is set to be lower than the speed of the conveyor belt 35 so that color misregistration does not occur.
• the electrostatic adsorption electrode 50 b is provided between the final printing head 3 and the discharge roller 40, the discharge speed of the discharge roller 40 is not reduced.
• the dimension of the sheet S in the conveyance direction could be made compact.
• FIG. 12 shows the electrostatic chucking electrode 5 0 b in the sheet conveying apparatus 30 in the seventh example (see FIG. 11) and the electrostatic chucking electrode 60 in the sixth example (see FIG. 10).
• the above-mentioned explanations (configuration, action, effect, etc.) are used with the reference numerals already given to the components corresponding to the functions or names.
• the sheet conveying device of each embodiment described above has been used as a means for conveying a sheet in an image forming apparatus provided with a printing head that discharges ink to form an image on a sheet.
• the present invention is not necessarily applied only to such an ink jet type image forming apparatus.
• the present invention can also be applied as a sheet conveying unit in a stencil printing apparatus, and an image using other image forming principles. It can also be applied to a forming apparatus or a printing apparatus, and is not limited to a sheet conveying means of an image forming apparatus, and is effective as a means for stably conveying a sheet corresponding to various industrial uses. It can be used.
• description of reference numerals of each part of the present embodiment used with reference to the drawings in the specification is collectively displayed.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Feeding Of Articles By Means Other Than Belts Or Rollers (AREA)
• Handling Of Sheets (AREA)
• Delivering By Means Of Belts And Rollers (AREA)
• Ink Jet (AREA)
• Handling Of Cut Paper (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=39562240

Family Applications (1)

Country Status (3)

Cited By (1)

Families Citing this family (10)

Citations (5)

Family Cites Families (6)

• 2006
  • 2006-12-22 JP JP2006346303A patent/JP4648297B2/ja active Active
• 2007
  • 2007-10-03 WO PCT/JP2007/069786 patent/WO2008078446A1/ja not_active Ceased
  • 2007-10-03 US US12/310,795 patent/US20100021219A1/en not_active Abandoned

Patent Citations (5)

Also Published As

Similar Documents

Legal Events