JP5517578B2 - Conveying mechanism and recording apparatus having the same - Google Patents

Description

  The present invention relates to a transport mechanism for transporting a recording medium by a transport belt, and a recording apparatus having the transport mechanism.

  An ink jet recording apparatus ejects minute ink droplets from a plurality of nozzles provided in a recording head to form an image on a recording medium. The recording head is mounted on a carriage provided so as to be movable in the width direction of the recording medium, and performs recording in the entire width direction while moving in the width direction of the recording medium, or in a row in the entire width direction of the recording medium. There are forms that are arranged and record.

  Also, the ink jet recording apparatus realizes so-called “edgeless recording” in which no margin is generated at the end of the recording medium by ejecting ink to a larger area beyond the end of the recording medium in the width direction. There is. When such borderless recording is performed, the ink ejected to the outside of the recording medium prevents the internal parts including the platen that supports the recording medium and the recording medium itself from being stained. For example, an opening is provided at the end of the platen in the width direction, and the ink discharged to the outside of the recording medium is discharged to the back side of the platen through the opening, or an absorber capable of absorbing ink is placed in the opening. A method of arranging and holding ink is considered. The ink absorbed by the absorber is collected as waste ink. In addition, there are a configuration in which the platen itself is formed from a material having ink absorbability, a configuration in which an ink recovery mechanism is connected to the platen, and the like (for example, Patent Document 1).

  As a method for transporting the recording medium, there is a method in which an endless belt is wound around a plurality of rollers including a driving roller, and the recording medium is transported in close contact with the belt surface. As one method for improving the adhesion of the recording medium to the belt, there is an electrostatic adsorption method in which a charge is applied to the belt surface and the recording medium is adsorbed to the belt by electrostatic force. In order to realize the above-described borderless recording in the electrostatic attraction conveyance method using such a belt (hereinafter referred to as “conveyance belt”), a plurality of conveyance belts are arranged in the width direction of the recording medium to be conveyed. Furthermore, there is a method in which such a conveyance belt is disposed so that a gap is formed at both ends in the width direction of the recording medium so that the conveyance belt is not stained with ink (for example, Patent Document 2). In this method, in order to cope with recording media of various sizes, a plurality of conveying belts are arranged so that spaces are formed at both ends in the width direction of each recording medium (see Patent Document 2 and FIG. 4).

JP 2002-337405 A JP 2005-305688 A

  In the conventional technique using the above-described transport belt, when a wide recording medium is transported, a gap provided for borderless recording of the narrow recording medium overlaps with the wide recording medium. In this gap, there is no close contact between the conveyance belt and the recording medium, so that the recording medium may be lifted.

  In addition, the ink used for recording uses water as a main solvent. When the recorded image has a high density, a large amount of water is driven onto the recording medium. It is known that the recording medium expands and becomes large due to the moisture of the ink, and a phenomenon (hereinafter referred to as “cockling”) occurs in which the recording medium is deformed in a wavy manner around the portion where the recording is performed. ing. This cockling reduces the distance between the recording medium and the recording head, and the recording medium comes into contact with the recording head and becomes dirty, or the distance between the recording medium and the recording head is not stable. There is a possibility that the landing position of the recording medium is shifted and the recording quality is deteriorated. In particular, at the position of the gap between the conveyance belts described above, since the conveyance belt and the recording medium are not in close contact, such a phenomenon is further promoted, and the above-described problems may be further aggravated.

  Therefore, the present invention solves the above-described problem, and has a transport mechanism that enables borderless recording, improves adhesion between the transport belt and the recording medium, and prevents the recording medium from floating from the transport belt. A recording device is provided.

The recording medium conveyance mechanism of the present invention includes a driving roller driven by a motor, a driven roller, a plurality of tension rollers, an endless central conveyance belt and a side conveyance belt wound around them, and a central conveyance. A belt and an inner peripheral portion of the side conveyance belt, and a platen located between the driving roller and the driven roller. The central conveyance belt is located at the center in the width direction of the recording medium to be conveyed, and the side conveyance belts are located on both sides in the width direction of the central conveyance belt. In addition, flanges that restrict movement of the side conveyance belt in the width direction are provided at both ends of the tension roller around which the side conveyance belt is wound. In addition, there is a moving mechanism for moving the tension roller around which the side conveyance belt is wound close to or away from the tension roller around which the central conveyance belt is wound . The tension roller around which the side conveyance belt is wound by the moving mechanism moves, and the side conveyance belt is rotated by the driving roller, so that the side conveyance belt approaches or separates from the central conveyance belt .

  According to the present invention, since the adhesion between the conveyance belt and the recording medium is enhanced, the recording medium does not easily float from the conveyance belt.

1 is a schematic perspective view of a recording medium transport mechanism of an ink jet recording apparatus according to the present invention. 2A and 2B are schematic views illustrating details of the recording medium conveyance mechanism in FIG. 1, in which FIG. 1A is a top view of the recording medium conveyance mechanism, and FIG. FIG. 2 is a schematic perspective view illustrating a side conveyance belt moving mechanism of the recording medium conveyance mechanism of FIG. 1. FIG. 6 is a top view of a recording medium conveyance mechanism showing a position of a conveyance belt when performing borderless recording on an L-size recording medium. FIG. 6 is a top view of a recording medium conveyance mechanism showing a position of a conveyance belt when performing borderless recording on an A4 size recording medium.

  Details of embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, the same number is attached | subjected to the structure which has the same function in an accompanying drawing, and the description may be abbreviate | omitted.

  FIG. 1 is a schematic perspective view of a recording medium transport mechanism 1 of an ink jet recording apparatus according to the present invention.

  The recording medium conveying mechanism 1 is provided with a central conveying belt 2 and side conveying belts 3 and 4 positioned on both sides in the width direction of the central conveying belt 2 in order to convey the sheet-like recording medium 5. The surfaces of the conveyance belts 2 to 4 on the conveyance path of the recording medium 5 become conveyance surfaces for conveying the recording medium 5. There are gaps 18 between the central transport belt 2 and the side transport belts 3 and 4, respectively. The conveyor belts 2 to 4 are endless belts, and an insulating layer is formed on the surface thereof. The side conveyance belts 3 and 4 are arranged symmetrically with respect to the center line C of the central conveyance belt 2. This center line C coincides with the center line in the width direction of the recording medium 5 being conveyed. The conveyor belts 2 to 4 are part of a driving roller 6, a driven roller 7, and a side conveyor belt moving mechanism 21 to be described later, and are wound around a tension roller 8 that is tensioned by a spring 9. Yes. A platen 10 is disposed between the driving roller 6 and the driven roller 7 at the inner periphery of the conveying belts 2 to 4. The driving roller 6 is connected to a conveying motor 11. The driving roller 6 is driven by the conveying motor 11, and the conveying belts 2 to 4 are driven in a state where tension is applied by the tension roller 8.

  In addition, a carriage 14 mounted with an ink tank 12 and a recording head 13 that moves in the width direction of the recording medium 5 (arrow B in the figure) and performs recording is provided.

  The recording medium 5 is conveyed from the paper feeding mechanism (not shown) to the recording medium conveying mechanism 1 one by one in the direction of arrow A, and the carriage 14 reciprocates in the width direction of the recording medium 5 to perform recording. The recording medium 5 is gradually conveyed in the direction of the arrow A along with the reciprocation of the carriage 14, and the recording medium 5 on which recording has been completed is discharged downstream in the conveying direction.

  2A and 2B are schematic views showing details of the recording medium transport mechanism 1 of FIG. 1, wherein FIG. 2A is a top view (partially perspective view) of the recording medium transport mechanism 1, and FIG.

  On the back surface of the central conveyance belt 2, slits 2 a are formed along the center line C at equal intervals along the entire circumference. An encoder sensor 16 is disposed on the surface of the platen 10 at a position facing the slit 2 a provided on the back surface of the central conveyance belt 2. The encoder sensor 16 detects the slit 2a and measures the amount of movement of the central conveying belt 2. The transport motor 11 is controlled by a control unit (not shown) that controls the operation of the transport motor 11. And according to the instruction | indication from a control part, according to the moving amount | distance of the center conveyance belt 2 detected by the encoder sensor 16, the conveyance motor 11 is driven or stopped.

  The conveyance belts 2 to 4 are sandwiched between the driving roller 6 and the power supply roller 17 at a position that is not the conveyance path of the recording medium 5. In the present embodiment, the conveyance belts 2 to 4 are sandwiched between the driving roller 6 and the power supply roller 17, but may be sandwiched between the power supply roller 17 and the driven roller 7 or the tension roller 8. Further, a voltage is applied to the power supply roller 17 when the recording medium 5 is transported, and charges are applied to the surfaces of the transport belts 2 to 4. Since the surfaces of the conveyor belts 2 to 4 are used as insulating layers as described above, this electric charge stays on the surfaces of the conveyor belts 2 to 4 and the surfaces of the recording medium 5 and the conveyor belts 2 to 4 that have been conveyed, that is, the recording medium. An electrostatic force is generated between the transfer surface 5 and the conveying surface 5 so as to adsorb them.

  Here, the central conveyance belt 2 is made of a material having a high elastic modulus such as polyimide or ETFE (ethylene tetrafluoride copolymer), and the side conveyance belts 3 and 4 are made of EPDM (ethylene-propylene-diene rubber), for example. Made of low elastic modulus material. In the state where no tension is applied, the peripheral length of the central transport belt 2 is set slightly longer than the peripheral length of the side transport belts 3 and 4. Since the central conveyance belt 2 has a high elastic modulus and little expansion and contraction, the center distance between the rollers 6, 7, 8 is determined by the central conveyance belt 2. On the other hand, since the side conveyance belts 3 and 4 have a low elastic modulus, the side conveyance belts 3 and 4 expand and contract in accordance with the inter-axis distance determined by the central conveyance belt 2.

  FIG. 3 is a schematic perspective view showing the side conveyance belt moving mechanism 21. The tension roller 8 includes a tension shaft 19, a central collar 22 that is coaxial with the tension shaft 19 and is provided so as to be idled with respect to the tension shaft 19, and side collars that are located on both sides of the central collar 22. 23, 24. The central conveying belt 2 (see FIG. 1) is wound around the central collar 22, and the side conveying belts 3 and 4 (see FIG. 1) are wound around the side collars 23 and 24, respectively. Flanges 25 and 26 are provided at both ends of the side collars 23 and 24, and the movement of the side conveyance belts 3 and 4 in the width direction is restricted by the flanges 25 and 26. Incidentally, the tension shaft 19 is connected to the spring 9 (see FIG. 1) as described above, and the tension roller 8 can apply tension to the conveyor belts 2 to 4.

  A moving lever 33 having a cylindrical portion 33a and an end plate 33b extending from both ends of the cylindrical portion 33a so as to sandwich the flange 25 is provided. Similarly, a moving lever 34 having a cylindrical portion 34a and an end plate 34b extending from both ends of the cylindrical portion 34a so as to sandwich the flange 26 is provided.

  The cylindrical portions 33a and 34a are respectively provided with rod-like lead screws 35 and 36 having a round cross section, and shafts 37 and 38 are respectively provided in the cylindrical portions 33a and 34a. Is provided. Grooves 35a and 36a opposite to each other are cut on the surfaces of the lead screws 35 and 36, and shafts 37 and 38 are fitted in the grooves 35a and 36a inside the cylindrical portions 33a and 34a, respectively. The end portions of the lead screws 35 and 36 located on the outer side in the width direction are rotatably supported by the chassis 39, and the end portions at the center portion in the width direction are coupled to the gears 40 and 41, respectively. A conveyance belt moving motor 51 is connected to the gears 40 and 41. Further, a shielding plate 33 c is provided on a part of the moving lever 33, and its position is detected by a photo sensor 52 fixed to the chassis 39. As described above, since the grooves 35a and 36a cut in the lead screws 35 and 36 are opposite to each other, the moving levers 33 and 34 are simultaneously moved to the center in the width direction with respect to driving of the conveyor belt moving motor 51. Or simultaneously, it can be moved outward in the width direction. Due to the movement of the moving levers 33, 34, the side collars 23, 24 sandwiched between both ends of the moving levers 33, 34 approach or separate from the central collar 22 along the shaft 19.

  With this mechanism, when the conveyor belt moving motor 51 is driven and the side collars 23 and 24 are moved while driving the conveyor motor 11 to rotate the conveyor belts 2 to 4, the side conveyor belts 3 and 4 are The position in the width direction can be moved following the side collars 23 and 24. That is, the side conveyance belts 3 and 4 can be brought close to or separated from the central conveyance belt 2. The position of the side collar 23 is detected by the photo sensor 52. When the side collar 23 reaches the designated position, the conveyance belt moving motor 51 is stopped and the movement of the side collars 23 and 24 is stopped.

  Various sizes are used as the recording medium 5. Here, a case where recording is performed on the L-sized recording medium 5a as an example of a small size and the A4-sized recording medium 5b as an example of a large size will be described. .

  FIG. 4 is a top view of the recording medium transport mechanism 1 showing the positions of the transport belts 2 to 4 when performing borderless recording on the L-size recording medium 5a. The solid line shows the L-size recording medium 5a, and the broken line shows the A4-size recording medium 5b.

  The width of the central conveying belt 2 is made slightly smaller than the recording medium 5a. The center side end portions 3a and 4a of the side conveyance belts 3 and 4 are arranged at positions away from the width direction end portion of the central conveyance belt 2, and a gap 18 between the central conveyance belt 2 and the side conveyance belts 3 and 4 is provided. The end of the recording medium 5a in the width direction is on the top. In this state, the outer end portions 3b and 4b of the conveyor belts 3 and 4 are set to be outside the end portions in the width direction of the A4 size recording medium 5b.

  Ink droplets ejected from the widthwise end of the recording medium 5 a land in the gap 18. Therefore, the moving mechanism of the present invention can perform borderless recording with no margin at the end of the recording medium 5a without soiling the conveyor belts 2 to 4.

  FIG. 5 is a top view of the recording medium conveying mechanism 1 showing the positions of the conveying belts 2 to 4 when performing borderless recording of the A4 size recording medium 5b. The side conveyor belts 3 and 4 are moved to the center in the width direction by the side conveyor belt moving mechanism 21 described above, and the gap 18 between the center conveyor belt 2 and the side conveyor belts 3 and 4 is reduced. At this time, the outer end portions 3b and 4b of the side conveyance belts 3 and 4 are moved to the center portion in the width direction, and are located inside the both end portions in the width direction of the recording medium 5b. As a result, as in the case of the above-described L-format recording medium 5a, the ink droplets ejected from both ends in the width direction of the A4-sized recording medium 5b land on the outside of the side conveyance belts 3 and 4. Therefore, it is possible to perform borderless recording with no margin at the end portion on the recording medium 5b without soiling the side conveyance belts 3 and 4.

  An ink absorber is provided on the platen 10 at a position where a gap 18 between the central conveyance belt 2 and the side conveyance belts 3 and 4 and ink liquid on the outside of the side conveyance belts 3 and 4 land. It is desirable to hold.

  As described above, since the side conveyance belts 3 and 4 are movably provided, the gap 18 between the central conveyance belt 2 and the side conveyance belts 3 and 4 can be changed. Furthermore, even if various sizes of the recording medium 5 are used, the range in which the recording medium 5 is not adsorbed to the conveying belts 2 to 4 can be reduced, so that the adhesion between the conveying belts 2 to 4 and the recording medium 5 is improved. This makes it difficult for the recording medium 5 to float from the conveyor belts 2 to 4. Therefore, the recording medium 5 can be stably conveyed.

  In the description of the present embodiment, the conveyance belts 2 to 4 are three, and the recording media 5a and 5b having two types of sizes of the L plate and the A4 plate have been described. Further, a plurality of side conveyance belts 3 and 4 are provided on both sides of the central conveyance belt 2 instead of one each, and a gap 18 between the conveyance belts is set in accordance with both ends of each recording medium 5 in the width direction. And they are provided to be movable. In this way, it is possible to deal with recording media 5 of various sizes.

  In the above description, the movement levers 33 and 34 are moved by one side conveyance belt moving motor 51. However, two side conveyance belt movement motors are prepared, and the movement levers 33 and 34 can be individually moved. You may do it.

DESCRIPTION OF SYMBOLS 1 Recording medium conveyance mechanism 2 Central conveyance belt 3, 4 side conveyance belt 5 Recording medium 6 Driving roller 7 Driven roller 10 Platen 11 Conveyance motor 21 Side conveyance belt moving mechanism

Claims (13)

A driving roller driven by a motor, a driven roller, a plurality of tension rollers, an endless central conveyance belt and a side conveyance belt wound around them, and the central conveyance belt and the side conveyance belt a platen positioned between the a circumferential portion said drive roller and said driven roller, the conveyance mechanism of the recording medium having,
The central conveying belt is located in the center in the width direction of the recording medium to be conveyed; the side conveying belts are located on both sides in the width direction of the central conveying belt;
At both ends of the tension roller around which the side conveyance belt is wound, flanges for restricting the movement of the side conveyance belt in the width direction are provided,
Have a moving mechanism for closer or away with respect to the tension roller to the tension roller, wherein the lateral conveyor belt is wound around said central conveyor belt wound over,
The tension roller around which the side conveyance belt is wound is moved by the moving mechanism, and the side conveyance belt is rotated by the driving roller, so that the side conveyance belt comes close to the central conveyance belt. Alternatively , a recording medium conveyance mechanism that is separated . Wherein said tension roller central conveyor belt is wound around the Ru idle allows der respect to the axis of the tension roller, the transport mechanism of the recording medium according to claim 1.   As a part of the moving mechanism, a cylindrical portion through which a lead screw having a round cross section and a groove cut in the surface passes, and both end portions of the side tension roller extending from both end portions of the cylindrical portion. A plurality of moving levers having end plates sandwiching the flanges are provided corresponding to the side tension rollers, and shafts that fit into the grooves are respectively provided inside the cylindrical portions. The transport mechanism according to claim 2, wherein   The conveyance mechanism according to claim 3, wherein the direction of the groove cut in the lead screw is reversed between the side tension rollers located at both ends of the central tension roller.   The transport mechanism according to claim 3 or 4, wherein a shield plate is provided on one of the moving levers, and a photosensor that detects the shield plate is provided at a position corresponding to the shield plate.   From the back surface of the said center conveyance belt, the slit engraved at equal intervals over the perimeter is provided, and it is the surface of the said platen, The encoder sensor is provided in the position facing the said slit. 6. The transport mechanism according to any one of 5 above. A plurality of the side conveyance belts and the tension rollers on which the side conveyance belts are wound are provided on both sides in the width direction of the central conveyance belt and the tension rollers on which the central conveyance belts are wound . The transport mechanism according to any one of claims 1 to 6.   An insulating layer is formed on the surfaces of the central conveyance belt and the side conveyance belt, and the central conveyance belt and the side conveyance belt are a driving roller or a driven roller and a power supply roller to which a voltage is applied. The conveyance mechanism according to claim 1, wherein the conveyance mechanism is sandwiched between the two.   A recording apparatus comprising the transport mechanism according to claim 1. A driving roller driven by a motor, a driven roller, a plurality of tension rollers, an endless central conveying belt wound around them, and side conveying belts arranged on both sides in the width direction of the central conveying belt, respectively When a method of conveying the recording medium in the transport mechanism of the recording medium having a platen between the driven roller and the inner a peripheral portion said drive roller of said side conveyor belt and the central conveyor belt,
The central conveyance belt and the side conveyance belt form a conveyance surface of the recording medium,
The tension roller provided with a flange that restricts movement of the side conveyance belt in the width direction at both ends is wound on the tension roller around which the central conveyance belt is wound. By rotating the side conveyance belt by driving the driving roller while approaching or separating from each other, it is arranged at the center in the width direction of the recording medium to be conveyed in accordance with the size of the recording medium to be conveyed. the relative central conveyor belt and the pre SL side conveyor belt close to or moved away that, in a position in contact with the end portion of the recording medium of the conveying surface, the central conveyor belt and said side conveyor belt is not positioned In the above-described state, the recording medium is conveyed by rotating the central conveyance belt and the side conveyance belt to convey the recording medium.   The side conveyance belt is brought close to the central conveyance belt so as to reduce a gap between the central conveyance belt and the side conveyance belt at a position in contact with the recording medium on the conveyance surface. The recording medium conveying method described. Slits cut at equal intervals over the entire circumference of the back surface of the central conveying belt are detected by an encoder sensor provided on the surface of the platen and facing the slit, and the amount of movement of the central conveying belt is measured. 12. A method for conveying a recording medium according to claim 10 or 11 . An insulating layer is formed on the surfaces of the central conveyance belt and the side conveyance belt, and the central conveyance belt and the conveyance belt are sandwiched between a power supply roller to which voltage is applied and the driving roller or the driven roller. by giving an electric charge to the surface of the conveyor belt the side conveyor belt, the recording medium and adsorbing said transport surface, transporting method of the recording medium according to any one of claims 10 12.

Images