JP5702207B2 - Paper transport mechanism - Google Patents

Description

  The present invention relates to a paper transport mechanism, and more particularly to a mechanism that reliably transports paper without causing paper jam or jam in a curved paper transport path.

  In a device that handles paper (plain paper, label printing paper, etc.) such as a printer, a facsimile, an auto document feeder, and a label printer, a mechanism for transporting the paper is used. The paper transport mechanism forms a paper transport path by variously combining a guide member such as a paper guide, a transport roller, a transport belt, and the like.

  In a portion (corner) where the paper conveyance path is bent or bent, paper jams and jams are likely to occur, which is a problem during paper feeding. In particular, when a thick sheet or a stiff sheet is passed through a curved sheet conveyance path, a force for bending the sheet becomes a load, which causes a decrease in conveyance accuracy and a jam.

  Conventionally, when cornering paper in an arbitrary direction, a guide member such as a paper guide or paper guide is provided with parts such as sheet metal, or a curved radius (curve radius) is increased by avoiding a small radius curve. As a result, smooth paper conveyance was achieved (see FIG. 4). For example, Patent Document 1 discloses a conventional example in which a sheet can be conveyed to a curved sheet conveyance path by installing a guide member.

  In addition to setting the guide member and increasing the radius of curvature, for example, a method of adsorbing the sheet to the conveyance belt by electrostatic adsorption or vacuum adsorption is known. However, in this method, a conveyor belt is essential.

Japanese Patent Laid-Open No. 08-059020

FIG. 4 shows an example of a conventional paper transport mechanism.
In the paper transport mechanism as shown in FIG. 4, the corner portion 20 is provided in the paper transport path formed by the upper guide plate 15 and the lower guide plate 16 that are guide members. A pair of rollers composed of a drive roller 21 and a tension roller 22 or a drive roller 23 and a tensioner are arranged in the middle of the sheet conveyance path so that the sheet P smoothly flows from the upstream <A> to the downstream <B> through the corner portion 20. A pair of rollers composed of rollers 24 and the like are appropriately arranged to feed the paper P and to control the direction of feeding by the guide member.

  However, the corner portion 20 has a problem of paper jam and a decrease in conveyance accuracy. When the corner portion 20 is narrowed, it becomes a load of paper conveyance, while when it is widened, the paper plays, so an appropriate gap is necessary.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a paper transport mechanism that reliably transports paper without causing paper jam or jam in a curved paper transport path.

  In order to achieve the above object, according to a first aspect of the present invention, as a first aspect, the sheet is sandwiched between a movable tension roller and a nip portion between the tension roller and a curved portion of the sheet conveyance path, and the sheet is placed on the sheet. Switching control is performed between a conveyance roller that conveys the conveyance path from upstream to downstream, a bracket that supports the tension roller at a position in contact with the outer periphery of the conveyance roller, and a state where rotation of the conveyance roller is transmitted to the bracket and a state where it is not transmitted. A first switching unit; and a second switching unit configured to switch between a state in which the rotation of the tension roller is fixed and a state in which the tension roller is not fixed. The first switching unit holds a sheet in the nip portion. Then, the rotation control of the transport roller is controlled to be switched from the state of not transmitting to the bracket, the bracket is interlocked with the rotation of the transport roller, The tension roller in a state where the sheet is sandwiched in the nip portion is moved to the end of the bending portion along the outer periphery of the transport roller, and the first switching means is configured to move the tension roller to the end of the bending portion. The rotation of the conveying roller is controlled to be switched from the state of transmitting to the bracket, and the second switching unit is controlled to switch from the state of fixing the rotation of the tension roller to the state of not fixing. A sheet transport mechanism is provided.

  According to the present invention, it is possible to reliably convey a sheet without causing a sheet jam or a jam in a curved sheet conveyance path.

It is a side view (home position) which shows the paper conveyance mechanism of embodiment of this invention. It is a side view (during bracket rotation) showing a paper conveyance mechanism of an embodiment of the present invention. FIG. 3 is a side view (terminal position) illustrating the paper transport mechanism according to the embodiment of the present invention. It is a side view which shows an example of the conventional paper conveyance mechanism.

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

FIG. 1 shows a side view of the present embodiment in the home position.
As illustrated, the paper transport mechanism according to the present embodiment has a curved portion (curve, corner) in the paper transport path. The curved portion includes a conveyance roller 11, a tension roller 12, a bracket 13, and a switching mechanism 14. The home position refers to a position where a nip formed by the conveying roller 11 and the tension roller 12 comes to the beginning of the curved portion.

  The paper P flows from the upstream <A> of the paper conveyance path guided by the guide plates 17 and 18 toward the downstream <B> of the paper conveyance path guided by the guide plates 15 and 16. The nip portion between the conveying roller 11 and the tension roller 12 when in the home position shown in FIG.

  The conveyance roller 11 and the guide plates 15, 16, 17 and 18 are fixed to an exterior member (not shown) and the positional relationship does not change. On the other hand, the tension roller 12 is movable. The tension roller 12 is supported at a position in contact with the outer periphery of the transport roller 11 by a bracket 13.

  The bracket 13 is positioned so that the rotation axis is the same as the rotation axis of the transport roller 11, and starts rotating when the rotation of the transport roller 11 is transmitted by the switching mechanism 14. On the other hand, when the transfer mechanism 11 is separated from the rotation of the transport roller 11, the rotation stops.

  The bracket 13 is separated from the rotation of the transport roller 11 by the switching mechanism 14 at the home position, and the rotation is not transmitted. Therefore, the tension roller 12 is fixed and carried at the home position. When the paper P comes from the <A> side, the tension roller 12 rotates in conjunction with the rotation of the conveying roller 11 that is in pressure contact with the leading end of the paper P. Nipping (nip).

  When the paper transport mechanism of the present embodiment is at the home position, the paper coming from the <A> side is sandwiched between the transport roller 11 and the tension roller 12. A sensor 19 at an arbitrary position on the upstream <A> side of the sheet conveyance path detects the passage of the leading end of the sheet, and is suitable for the sheet to be sandwiched (nipped) between the conveyance roller 11 and the tension roller 12. At the timing, the switching mechanism 14 performs switching control from a state in which the rotation of the transport roller 11 is not transmitted to the bracket 13 to a state in which the rotation is transmitted.

In FIG. 2, the side view of this embodiment in which the bracket 13 is rotating is shown.
As shown in FIG. 2, when the bracket 13 rotates, the tension roller 12 also moves in conjunction with the outer periphery of the transport roller 11 like a satellite orbit. Since the bracket 13 rotates in conjunction with the transport roller 11 and the leading end of the paper is sandwiched between the tension rollers, the paper P is also transported through the curved portion in conjunction with the transport roller 11.

  The tension roller 12 also has a switching mechanism (not shown), and the switching mechanism controls the switching of the tension roller 12 between a fixed state and a non-fixed state. When the rotation of the conveying roller 11 is transmitted to the bracket 13 by the switching control by the switching mechanism 14 and the tension roller 12 starts to rotate around the outer periphery of the conveying roller 11, the tension roller 12 switching mechanism also prevents the tension roller from rotating. Fix it. Therefore, the paper P is nipped by the nip portion and is conveyed in the curved portion in that state.

FIG. 3 shows a side view of the present embodiment in the terminal position.
The term “end position” refers to a position when the nip portion reaches the end of the curved portion. The switching mechanism 14 detects that the nip portion has reached the end of the bending portion, and switches from a state where the rotation of the conveying roller 11 is transmitted to the bracket 13 to a state where it is not transmitted.

  As a result, the rotation of the bracket 13 stops and the movement of the tension roller 12 that rotates on the satellite orbit also stops. The tension roller 12 is fixed to the position shown in FIG. 3 for a while. The transport roller 11 continues to rotate and sends the paper P to the downstream <B> side of the paper transport path.

  Although the above-described embodiment has a curved portion (corner portion), the guide portion is not provided in the curved portion, and therefore, paper jam and jam are unlikely to occur. Further, as described above, since the paper P passes through the curved portion with the tension roller 12 movable by the bracket 13 and the transport roller 11 being sandwiched, the paper P is reliably transported. Further, since the degree of freedom of the sheet at the corner portion is suppressed, the sheet conveyance is stabilized, the sheet jam is reduced, and the sheet conveyance accuracy is improved. Therefore, according to the present embodiment, it is possible to reliably transport the paper without causing paper jam or jamming in the curved paper transport path.

  In the present embodiment, after the state of FIG. 3, the conveyance roller 11 continues to rotate until the paper P is discharged, and when the paper P is discharged from the nip portion, the conveyance roller 11 is reversely rotated. Then, substantially simultaneously with the start of reverse rotation of the transport roller 11, the switching mechanism 14 performs switching control from a state where the rotation of the transport roller 11 is not transmitted to the bracket 13 to a state where the rotation is transmitted. Therefore, the bracket 13 rotates reversely in conjunction with the reverse rotation of the transport roller 11.

  When the tension roller 12 returns from the state of FIG. 3 to the state of FIG. 1 (home position) through the state of FIG. 2, the switching mechanism 14 does not transmit the rotation of the transport roller 11 from the state of transmitting to the bracket 13. Switch control to.

  Therefore, according to the present embodiment, even after a single sheet is conveyed, the next sheet can be appropriately sent, and continuous paper can be handled.

  Further, the switching mechanism 14 of the present embodiment may be any means that can lock or unlock the bracket 13 on the rotation shaft of the transport roller 11, and is preferably realized by, for example, an electromagnetic clutch. Locking or unlocking the shaft means, in other words, whether it is interlocked (followed) with the rotation of the shaft or separated. In other words, switching control is performed between a state in which the rotation of the transport roller 11 is transmitted to the bracket 13 and a state in which the rotation is not transmitted.

  In this embodiment, the bracket is fixed at two positions, ie, a home position and a terminal position. However, a plurality of positions may be used, and a sheet separator “separator” may be formed by stopping at any angle. it can. Thus, this embodiment can be variously modified and applied.

DESCRIPTION OF SYMBOLS 11 Conveyance roller 12 Tension roller 13 Bracket 14 Switching mechanism 15, 16, 17, 18 Guide plate 19 Sensor 20 Corner part 21, 23 Drive roller 22, 24 Tension roller

Claims (3)

In the curved part of the paper transport path,
A movable tension roller;
A conveyance roller for nipping a sheet in a nip portion with the tension roller and conveying the sheet from upstream to downstream of the sheet conveyance path;
A bracket for carrying the tension roller at a position in contact with the outer periphery of the transport roller;
First switching means for performing switching control between a state in which the rotation of the conveying roller is transmitted to the bracket and a state in which the rotation is not transmitted to the bracket;
Second switching means for switching and controlling a state in which the rotation of the tension roller is fixed and a state in which the tension roller is not fixed;
With
The first switching unit performs switching control from a state in which the rotation of the transport roller is not transmitted to the bracket when the sheet is sandwiched in the nip portion,
The bracket moves the tension roller in a state where the sheet is sandwiched in the nip portion in conjunction with the rotation of the conveyance roller, to the end of the curved portion along the outer periphery of the conveyance roller,
When the tension roller reaches the end of the bending portion, the first switching unit performs switching control from a state where the rotation of the conveying roller is transmitted to the bracket to a state where the rotation is not transmitted to the bracket,
The second switching means performs switching control from a state of fixing the rotation of the tension roller to a state of not fixing ,
The paper transport mechanism , wherein the transport roller continues to rotate after the switching control of the first switching unit and the second switching unit and transports the paper. The conveying roller rotates backward when the nipped paper is discharged from the nip portion at the end of the curved portion,
The first switching means performs switching control from a state in which the rotation of the conveyance roller is not transmitted to the bracket when the conveyance roller rotates in a reverse direction,
The bracket moves the tension roller along the outer periphery of the conveyance roller to the start end of the curved portion in conjunction with the reverse rotation of the conveyance roller.
The paper transport mechanism according to claim 1, wherein: The paper transport mechanism according to claim 1, wherein the first switching unit performs the switching control by an electromagnetic clutch.

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