JP2006124136A - Paper feeding device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feeding device capable of stably feeding a rolled paper, while preventing floating of a part of the rolled paper from a platen. <P>SOLUTION: A stiffening unit 100 for eliminating or relaxing curl of the rolled paper P before the rolled paper P reaches an image forming area is arranged between a feeding roller 56 and the image forming area. The stiffening unit 100 is provided with two rotary shafts 102 and 104 arranged to be positioned on both surface sides (an upper surface(image forming surface) and a lower surface) in a part of the rolled paper P, which just passes through the carrying roller 56. The rotary shaft 102 is extended on the upper surface side of the rolled paper P in parallel with a direction expressed with an arrow B. The rotary shaft 104 is extended on the lower surface side of the rolled paper P in parallel with the direction expressed with the arrow B. Length of the rotary shafts 102 and 104 is formed sufficiently longer than width of the platen 16 (length in the direction expressed with the arrow B). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a paper conveyance device that conveys a roll paper by a pair of rollers, and an image forming apparatus incorporating the paper conveyance device.

  2. Description of the Related Art Inkjet image forming apparatuses that form images by ejecting ink from a print head (recording head) to a recording medium such as recording paper are widely used. In this image forming apparatus, usually, a platen on which a portion where ink is ejected of a recording medium is placed, a pair of rollers (carrying roller and pinch roller) that sandwich the recording medium and convey it toward the platen, A paper discharge roller that sandwiches and discharges an image-formed portion of the recording medium is provided.

  The platen is positioned below the print head, and the distance (interval) from the print head to the platen is kept constant to form a high-quality image. In order to keep the distance from the print head to the recording medium at this constant interval, a suction unit is provided for sucking the recording medium to the platen for close contact. Since the recording medium is brought into close contact with the platen by the suction unit, the recording medium does not float from the platen, and the distance from the print head to the recording medium is kept constant.

  Incidentally, some of the above-described image forming apparatuses form an image on a roll paper wound in a roll shape. In this type of image forming apparatus, the roll paper is pulled out from one end and an image is formed on the pulled-out portion. In many cases, the rolled-out portion of the roll paper still has a curled curl when curled. When the roll paper is pulled out with a curl ridge, even if the suction unit is activated, the pulled-out portion may not be in close contact with the platen and may remain partly raised. If a part of the pulled-out part remains floating, the lifted part may come into contact with the print head or a paper jam may occur.

  When the suction force of the suction unit is increased in order to prevent the above-described lifting, there is a possibility that the conveyance of the roll paper may be hindered by the increased suction force. When the leading edge of the roll paper does not reach the paper discharge roller, the leading edge of the roll paper is in close contact with the platen only by the suction force of the suction unit. For this reason, in an image forming apparatus of a type in which the distance from the transport roller to the paper discharge roller is long, there is a risk that skewing or the like may occur when a part of the roll paper drawn out remains floating.

  In view of the above circumstances, an object of the present invention is to provide a paper conveyance device and an image forming apparatus that can stably convey a roll paper without part of the roll paper floating from the platen.

In order to achieve the above object, a paper transport device of the present invention is a paper transport device that sandwiches roll paper between a pair of rollers and transports the platen in a predetermined transport direction.
(1) It is provided with a seating unit disposed on the downstream side in the transport direction with respect to the pair of rollers to remove or alleviate curl of the roll paper.

here,
(2) The pair of rollers may be configured such that a tangent line at a nip where the roll paper is sandwiched intersects the platen.

Also,
(3) The pair of rollers may be configured such that a tangent line at a nip where the roll paper is sandwiched is parallel to the upper surface of the platen.

further,
(4) a discharge roller disposed between the platen and the downstream side in the transport direction for sandwiching and discharging the roll paper;
(5) A speed at which the paper discharge roller conveys the roll paper may be configured to be higher than a speed at which the pair of rollers convey the roll paper.

Furthermore,
(6) The waist unit may include a plurality of rollers.

Furthermore,
(7) The plurality of rollers may be arranged side by side in a paper width direction orthogonal to the transport direction.

Furthermore,
(8) The plurality of rollers are
(8-1) An upper surface side roller that contacts the upper surface of the roll paper being conveyed;
(8-2) Consists of a lower surface side roller that contacts the lower surface of the roll paper being conveyed,
(9) The position where the upper surface side roller contacts the upper surface of the roll paper may be lower than the position where the lower surface side roller contacts the lower surface of the roll paper.

Furthermore,
(10) The plurality of rollers may be
(10-1) an upper surface side roller that contacts the upper surface of the roll paper being conveyed;
(10-2) It consists of a lower surface side roller that comes into contact with the lower surface of the roll paper being conveyed,
(11) The position where the lower surface side roller contacts the lower surface of the roll paper may be higher than the position where the upper surface side roller contacts the upper surface of the roll paper.

Furthermore,
(12) The plurality of rollers of the seating unit are:
(13) It may be faster than the conveying speed of the pair of rollers and slower than the conveying speed of the paper discharge roller.

Furthermore,
(14) Instead of the lower surface side roller, a rib-shaped member may be arranged.

Furthermore,
(15) When the leading edge of the roll paper being conveyed passes over the platen and reaches the paper discharge roller, the seating unit is configured to release the function of removing or mitigating curl wrinkles. May be.

Furthermore,
(16) When the leading end of the roll paper being transported passes over the platen, the seating unit may be configured to release the function of removing or mitigating curl wrinkles.

Furthermore,
(17) The backrest unit may be configured to release the function of removing or mitigating curl wrinkles during backfeeding in which the roll paper is transported in a direction opposite to the transport direction.

An image forming apparatus of the present invention for achieving the above object is
(18) The above-described paper transport device is provided, and an image is formed on the roll paper transported to the paper transport device.

  According to the present invention, since the curl of the roll paper is removed or alleviated by the seating unit, the roll paper comes into close contact with the platen by the suction force in the platen. As a result, the roll paper can be stably conveyed without part of the roll paper floating from the platen.

  The present invention has been realized in a printer that forms an image on a roll paper label on which a plurality of labels are temporarily attached.

  With reference to FIGS. 1 and 2, the overall configuration of a printer which is an example of an image forming apparatus of the present invention will be described.

  FIG. 1 is a side view schematically showing a printer which is an example of an image forming apparatus of the present invention. FIG. 2 is a top view showing the carriage unit and its periphery of the printer of FIG.

  The printer 10 is connected to a host PC (personal computer) (not shown) that sends image information to the printer 10. The printer 10 includes a carriage body 12 on which four print heads 22K, 22C, 22M, and 22Y (print head 22) are mounted. The carriage body 12 scans (reciprocates) in a direction perpendicular to the paper surface of FIG. 1 (a direction perpendicular to the arrow A direction, an arrow B direction (scanning direction) in FIG. 2 and also a paper width direction). . The four print heads 22K, 22C, 22M, and 22Y are mounted on the carriage body 12 side by side in the conveyance direction (arrow A direction) of the recording medium (roll paper in this case) P. The four print heads 22K, 22C, 22M, and 22Y respectively eject black, cyan, magenta, and yellow inks. These four print heads 22K, 22C, 22M, and 22Y scan (reciprocate) in the scanning direction together with the carriage body 12. A detection sensor 53 that detects the position of the carriage body 12 is disposed in the vicinity of the scanning area of the carriage body 12.

  The roll paper P is supplied from the roll paper supply unit 14 and is conveyed in the direction of arrow A on the platen 16 by a paper conveyance device 60 incorporated in the printer 10. The paper transport device 60 includes a pinch roller 54 and a transport roller 56 that transport the roll paper P to the lower side (image forming area) of the print head 22. The roll paper P is pinched by the pinch roller 54 and the transport roller 56 and transported in the direction of arrow A. A spur 58 and a discharge roller 59 for discharging the roll paper P while sandwiching the roll paper P are arranged on the downstream side in the transport direction from the image forming area. A detection sensor 61 for detecting the roll paper P is disposed between the pinch roller 54 and the image forming area, and a detection sensor for detecting the roll paper P between the spur 58 and the image forming area. 62 is arranged. Details of the paper transport device 60 will be described later with reference to FIGS.

  When an image is formed on the roll paper P, the roll paper P being transported is temporarily (temporarily) stopped by the transport roller 56 or the like, and each print head is based on the recording data (image information). A color image is formed on the roll paper P by selectively ejecting ink from the ink 22. The printer 10 includes main tanks 24K, 24C, 24M, and 24Y that store ink supplied to the print heads 22K, 22C, 22M, and 22Y, and the main tanks 24K, 24C, and the like. Ink supply tubes 26K, 26C, 26M, and 26Y that connect the print heads 22K, 22C, 22M, and 22Y to 24M and 24Y are provided.

  The printer 10 is also provided with two guide rails 18 and 20 for guiding the carriage body 12 in the scanning direction (arrow B direction). The carriage body 12 and the guide rail 18 are in contact via a bearing 82 or the like. On the other hand, the carriage body 12 and the guide rail 20 are in contact via a rolling bearing 90.

  A part of the endless drive belt 30 is fixed to one end portion (fixed portion 12a) in the arrow A direction of the carriage body 12. On the other hand, a part of the endless drive belt 40 is fixed to the other end portion (fixed portion 12b) in the arrow A direction of the carriage body 12. The two drive belts 30 and 40 extend in the scanning direction. In order to prevent the carriage body 12 from unstablely moving in the scanning direction due to a phase shift between the two drive belts 30 and 40, the position of the fixing portion 12b can be freely adjusted in the scanning direction. And can be fixed.

  Both ends in the longitudinal direction of the drive belt 30 are stretched over pulleys 32 and 34, and the drive belt 30 is stretched with a predetermined tension. Both ends in the longitudinal direction of the drive belt 40 are stretched over pulleys 42 and 44, and the drive belt 40 is stretched with a predetermined tension. The pulleys 34 and 44 are fixed to the drive shaft 36a of the drive motor 36. When the drive motor 36 is driven, the drive belts 30 and 40 are rotated, and the print head 22 is scanned in the scanning direction together with the carriage body 12. The drive shaft 36a extends in the direction of arrow A, and synchronizes the rotation of the drive belts 30 and 40. Further, the pulleys 32 and 42 are configured to be freely movable and fixed in the scanning direction (arrow B direction) in order to keep the tension of the drive belts 30 and 40 properly.

  With reference to FIG. 3 and FIG. 4, the above-described paper transport device 60 will be described.

  FIG. 3 is a side view schematically showing the paper conveying apparatus. FIG. 4 is a front view showing the seating unit of the paper conveying apparatus of FIG.

  In addition to the pinch roller 54 and the transport roller 56, the spur 58 and the paper discharge roller 59, the paper transport device 60 includes a seating unit 100 that removes or relieves the curl of the roll paper P. Further, the paper transport device 60 includes a transport motor for rotating the transport roller 56 and the paper discharge roller 59, an adjustment roller 72 for adjusting the tension of the transport belt 74 described later, and the driving force of the transport motor 70. 56, a discharge roller 59, a conveyance belt 74 that transmits to the adjustment roller 72, and the like. The conveyance belt 74 is hung on the rotation shafts of the conveyance roller 56, the paper discharge roller 59, and the adjustment roller 72.

  Tangent line S (the pinch roller 54 of the pinch roller 54 and the conveyance roller 56) (the nip, the portion where the pinch roller 54 and the conveyance roller 56 are in contact via the roll paper P). A line segment L connecting the rotation center and the rotation center of the conveyance roller 56 intersects the platen 16 at a straight line perpendicular to the nip. That is, the rotation center shaft 54 a of the pinch roller 54 is located downstream of the rotation center shaft 56 a of the transport roller 56 in the transport direction. For this reason, the roll paper P sandwiched between the pinch roller 54 and the conveyance roller 56 passes through the nip and is conveyed so as to be pressed against the platen 16 as shown in FIG. For this reason, the roll paper P tends to be in close contact with the platen 16. Note that the pinch roller 54 and the conveying roller 56 may be arranged so that the tangent line of the nip described above is parallel to the upper surface of the platen 16.

  A plurality of holes are formed in the platen 16, and the roll paper P is adsorbed onto the platen 16 by a suction fan 17 disposed below the platen 16. The roll paper P conveyed on the platen 16 passes through the image forming area (below the print head 22) and reaches a paper discharge roller 59 disposed downstream of the image forming area in the conveying direction. It is discharged from the printer 10. Further, in order to prevent the roll paper P from being loosened while the roll paper P is being transported by the transport roller 56, the paper discharge roller 59 has a rotational speed (about 10%) compared to the transport roller 56. The transport speed is set to be faster. Here, the diameter of the paper discharge roller 59 is made larger than the diameter of the transport roller 56 so that the transport speed of the paper discharge roller 59 is faster than the transport speed of the transport roller 56. In addition, a one-way clutch (not shown) is used to prevent the occurrence of slack when the roll paper P is transported in the direction opposite to the normal transport direction (arrow A direction) (hereinafter referred to as back feed). The paper discharge roller 59 is configured not to be driven in the back feed direction.

  The seating unit 100 removes or alleviates curl of the roll paper P before reaching the image forming area, and is disposed between the transport roller 56 and the image forming area. As shown in FIG. 4, the seating unit 100 is disposed so as to be positioned on both sides (upper surface (image forming surface) side and lower surface side) of the portion of the roll paper P immediately after passing through the conveyance roller 56. The two rotating shafts 102 and 104 are provided. The rotating shaft 102 extends on the upper surface side of the roll paper P in parallel with the arrow B direction. The rotating shaft 104 extends on the lower surface side of the roll paper P in parallel with the arrow B direction. The lengths of the rotating shafts 102 and 104 are sufficiently longer than the width of the platen 16 (length in the direction of arrow B). Note that the waist unit 100 may be disposed between the platen 16 and the transport roller 56. A rotation shaft of a motor (not shown) that rotates the rotation shaft 102 is connected to one end portion in the longitudinal direction of the rotation shaft 102 (or 104). By driving this motor, the rotating shaft 102 rotates at a predetermined rotational speed.

  A plurality of upper surface side rollers 112 (only one is shown in FIG. 4) is fixed to the rotating shaft 102. The plurality of upper surface side rollers 112 are fixed in the direction of arrow B (paper width direction) at equal intervals, and contact the upper surface of the roll paper P. A plurality of lower surface side rollers 114 (only two are shown in FIG. 4) are fixed to the rotating shaft 104. The plurality of lower surface side rollers 114 are fixed at equal intervals in the direction of arrow B, and contact the lower surface of the roll paper P. The position where the upper surface roller 112 contacts the upper surface of the roll paper P (upper surface contact position) is lower than the position where the lower surface roller 114 contacts the lower surface of the roll paper P (lower surface contact position) by a distance L. . In other words, the position where the lower surface side roller 114 contacts the lower surface of the roll paper P is higher by the distance L than the position where the upper surface side roller 112 contacts the upper surface of the roll paper P. Further, as shown in FIG. 4, the upper surface side roller 112 and the lower surface side roller 114 are arranged at positions shifted from each other in the arrow B direction.

  As described above, the upper surface side roller 112 and the lower surface side roller 114 are alternately arranged in the direction of arrow B, and the upper surface contact position is lower than the lower surface contact position (the lower surface contact position is higher than the upper surface contact position). -The “waist” can be forcibly attached to the portion of the paper P before reaching the image forming area. For this reason, the curl wrinkles of the roll paper P are removed or alleviated by the seating unit 100, so that the roll paper P comes into close contact with the platen 16 by the suction force in the platen 16. As a result, the roll paper P can be stably conveyed without a part of the roll paper P rising from the platen 16.

  The positional relationship between the rotating shaft 102 of the upper surface side roller 112 and the rotating shaft 104 of the lower surface side roller 114 is the same as the positional relationship between the rotating shaft 56a of the conveying roller 56 and the rotating shaft 54a of the pinch roller 54. It is arranged so as to be located on the downstream side in the transport direction from 104. That is, as shown in FIG. 3, the upper surface side roller 112 is located slightly downstream of the lower surface side roller 114 in the transport direction. For this reason, the roll paper P that has passed through the seating unit 100 is conveyed so as to be pressed against the platen 16, as shown in FIG. As a result, the roll paper P becomes easier to adhere to the platen 16.

  The upper surface side roller 112 is fixed to the rotating shaft 102 via an elastic body such as a spring. Similarly, the lower surface side roller 114 is fixed to the rotating shaft 104 via an elastic body such as a spring. By adjusting the elastic force of the elastic body, the pressure (contact pressure) when the upper surface side roller 112 and the lower surface side roller 114 are in contact with the roll paper P can be adjusted. "Can be adjusted. In addition, without using the above-mentioned spring, the upper surface side roller 112 is directly fixed to the rotating shaft 102 and the lower surface side roller 114 is directly fixed to the rotating shaft 104, and both ends of the rotating shafts 102, 104 in the longitudinal direction are fixed. The portion may be urged toward the roll paper P by a spring, and the strength of the “waist” of the roll paper P may be adjusted by adjusting the urging force of the spring.

  When the leading edge of the roll paper P being conveyed passes the detection sensor 62 (see FIG. 1) (or the platen 16) on the paper discharge side and reaches the paper discharge roller 59, the roll paper P reaches the platen 16. Since they are in close contact with each other, the lower surface roller 114 is moved down together with the rotating shaft 104 so that the seating function (function of removing or relaxing curl wrinkles) of the seating unit 100 is released. A configuration for lowering the lower surface side roller 114 together with the rotating shaft 104 includes a configuration in which the rotating shaft 104 is moved up and down using a solenoid.

  Further, when the roll paper P is back-fed and returned to the paper feeding side, the lowering side roller 114 together with the rotating shaft 104 is lowered to release the lowering function of the lowering unit 100 as described above. It is configured as follows. Note that the upper surface side roller 112 may be moved up and down together with the rotating shaft 102.

  Further, the rotational speed (conveyance speed) of the upper surface side roller 112 and the lower surface side roller 114 is configured to be faster than the rotational speed of the transport roller 56 but slower than the rotational speed of the paper discharge roller 59. For this reason, looseness of the roll paper P is reliably prevented. Further, when the leading end of the roll paper P being transported passes over the platen 16, the roll paper P easily adheres to the platen 16, so that the curl wrinkles of the seating unit 100 are removed or alleviated. The conveyance resistance may be reduced by configuring so as to be released.

  Instead of the lower surface side roller 114 described above, a rib-shaped member may be arranged. However, it is preferable that the upper surface side roller 112 in contact with the printing surface (the upper surface of the roll paper P) is a rotating body such as a roller in consideration of the slidability with the roll paper P.

1 is a side view schematically showing a printer which is an example of an image forming apparatus of the present invention. FIG. 2 is a top view showing a carriage unit and its periphery of the printer of FIG. 1. It is a side view which shows a paper conveying apparatus typically. FIG. 4 is a front view showing a seating unit of the paper conveyance device in FIG. 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Printer 16 Platen 54 Pinch roller 56 Conveyance roller 59 Paper discharge roller 100 Seating unit 102,104 Rotating shaft 112 Upper surface side roller 114 Lower surface side roller

Claims (14)

In a paper conveyance device that nipping a roll paper between a pair of rollers and conveying the platen in a predetermined conveyance direction,
A paper conveying apparatus comprising a seating unit disposed on a downstream side of the pair of rollers in the conveying direction to remove or relieve curl of the roll paper. The pair of rollers is
2. The paper conveying apparatus according to claim 1, wherein a tangent at a nip where the roll paper is sandwiched intersects the platen. The pair of rollers is
2. The paper conveying apparatus according to claim 1, wherein a tangent line at a nip where the roll paper is sandwiched is parallel to the upper surface of the platen. A paper discharge roller disposed on the downstream side in the transport direction from the platen and configured to sandwich and discharge the roll paper;
4. The paper conveying apparatus according to claim 1, wherein a speed at which the paper discharge roller conveys the roll paper is faster than a speed at which the pair of rollers conveys the roll paper. . The seating unit is
The paper conveying device according to any one of claims 1 to 4, wherein the paper conveying device comprises a plurality of rollers. The plurality of rollers are:
The paper conveying apparatus according to claim 5, wherein the paper conveying device is arranged side by side in a paper width direction orthogonal to the conveying direction. The plurality of rollers are:
It consists of an upper surface side roller that contacts the upper surface of the roll paper being conveyed and a lower surface side roller that contacts the lower surface of the roll paper being conveyed,
7. The paper according to claim 6, wherein the position where the upper surface side roller contacts the upper surface of the roll paper is lower than the position where the lower surface side roller contacts the lower surface of the roll paper. Conveying device. The plurality of rollers are:
It consists of an upper surface side roller that contacts the upper surface of the roll paper being conveyed and a lower surface side roller that contacts the lower surface of the roll paper being conveyed,
7. The paper according to claim 6, wherein the position where the lower surface side roller contacts the lower surface of the roll paper is higher than the position where the upper surface side roller contacts the upper surface of the roll paper. Conveying device. The plurality of rollers of the seating unit are
9. The paper transport device according to claim 5, wherein the paper transport device is faster than a transport speed of the pair of rollers and slower than a transport speed of the paper discharge roller. 10. . Instead of the lower side roller,
The paper conveying device according to claim 7, 8, or 9, wherein a rib-shaped member is arranged. The function of removing or relieving curl wrinkles is released when the leading edge of the roll paper being conveyed passes over the platen and reaches the paper discharge roller. Item 11. The paper conveying device according to any one of Items 1 to 10. 11. The function of removing or mitigating curl wrinkles is released when the leading edge of the roll paper being conveyed passes over the platen. The paper conveying apparatus as described in any one of them. 13. The backrest unit is released from a function of removing or relieving curl wrinkles when a roll paper is conveyed in a direction opposite to the conveying direction. The paper conveyance apparatus as described in any one of these. A paper conveyance device according to any one of claims 1 to 13, comprising:
An image forming apparatus for forming an image on a roll paper conveyed to the paper conveying apparatus.

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