JP2008213979A - Image recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lightweight and compact image recording device capable of reliably and smoothly inverting a recording paper. <P>SOLUTION: A compound machine 10 comprises a conveying passage 23, a feeding unit 15 for feeding a recording paper to the conveying passage 23, a recording unit 24 for recording an image on the recording paper, and a paper delivery tray 21 provided on the downstream side in the conveying direction of the conveying passage 23. An inversion guide unit 16 for inverting the recording paper upside down is provided. The inversion guide unit 16 connects a downstream side part 36 of the conveying passage 23 to an upstream side part 37 thereof. A path changing unit 41 for feeding the recording paper to the paper delivery tray 21 side or the inversion guide unit 16 side is provided. The inversion guide unit and the path changing unit 41 comprise a first roller 45, a second roller 46 and an auxiliary roller 47, respectively. The second roller 46 and the auxiliary roller 47 are turned around the axis of the turning center of the first roller 45. In other words, the second roller 46 rolls on a circumferential surface of the first roller 45. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a structure of an image recording apparatus that records images on both sides of a recording medium by reversing the recording medium.

  Conventionally, there has been proposed an image recording apparatus capable of recording images on both front and back sides of a recording sheet. This type of image recording apparatus pulls out a recording sheet from a paper feed tray and conveys the recording sheet along a conveyance path formed in a U-shape. A recording unit is disposed in the conveyance path, and the recording unit records an image on one surface (either the front surface or the back surface) of the recording sheet being conveyed. Here, when an image is recorded only on one side, the recording sheet is sent to the downstream side of the conveyance path and discharged. However, when an image is recorded on the other side, the recording paper is once returned to the reversing path and sent again to the upstream side of the conveyance path (upstream side of the recording unit). The recording unit records an image on the other side of the recording paper that is reversed upside down (either the front side or the back side), and then discharges the image (see, for example, Patent Document 1).

JP 2004-224057 A

  By the way, in the conventional image recording apparatus, a flap is provided at a branch point between the conveyance path and the reversing path. By rotating this flap, the recording paper is sent to the downstream side of the conveying path or to the reversing path. It was returned. When the recording paper is returned to the reversing path, the flap closes the upstream side of the conveyance path and constitutes a guide plate that guides the recording paper to the reversing path. Then, when the pair of paper discharge rollers for discharging the recording paper is reversed, the end of the recording paper is pressed against the flap and enters the reverse path while being elastically curved.

  However, when the recording paper is elastically deformed by pressing the recording paper against the flap in this way, a part of the driving force of the paper discharge roller pair is consumed for elastic deformation of the recording paper, and the paper conveyance force is reduced.

  In order to cope with this, if the driving force of the paper discharge roller pair is set large, a new problem arises that the motor for driving the paper discharge roller pair becomes large and the entire apparatus becomes large.

  Accordingly, an object of the present invention is to provide a lightweight and compact image recording apparatus capable of reliably and smoothly reversing a recording sheet.

  (1) In order to achieve the above object, an image recording apparatus according to the present invention includes a conveyance path through which a recording medium is conveyed, a feeding unit that sends the recording medium to the conveyance path, and a conveyance path. A recording unit for recording an image on the recording medium, a paper discharge unit provided on the downstream side in the transport direction from the transport path, and a downstream of the recording unit in the transport path to reverse the recording medium. A reversing guide portion connecting the side portion and the upstream portion, and the downstream portion, and the recording medium can be sent to the paper discharge portion by sandwiching the recording medium and rotating forward, A roller pair capable of feeding the recording medium to the reversing guide unit by sandwiching the recording medium and rotating in reverse, and an auxiliary roller disposed on the upstream side in the transport direction from the roller pair. The rotation center axis of one of the rollers is the center of oscillation And a path switching unit that swings between the recording medium discharge attitude and the recording medium inversion attitude.

  The recording medium on which an image is recorded on one side is sandwiched by a pair of rollers in the path switching unit. As the roller pair rotates forward, the recording medium is sent to the paper discharge unit. At this time, the path switching unit is in a recording medium ejection posture. When the rear end portion of the recording medium reaches the specified position upstream of the auxiliary roller, the path switching unit assumes the recording medium reversing posture. Thereby, the rear end portion of the recording medium is pressed by the auxiliary roller and directed toward the reverse guide portion. Thereafter, when the roller pair is rotated in the reverse direction, the recording medium is changed in the transport direction and sent to the reverse guide unit.

  When the path switching unit changes to the recording medium reversal posture, it swings about the rotation center axis of one of the rollers. That is, the roller pair relatively rolls on the circumferential surface while holding the recording medium, and the auxiliary roller presses the recording medium. Therefore, the recording medium is reliably sent to the reverse guide unit without increasing the driving force of the roller pair. Thereafter, the recording medium is sent again to the recording unit, and an image is recorded on the other side. The recording medium on which the images are recorded on both sides is sandwiched by the roller pair of the path switching unit, and is sent to the paper discharge unit by the normal rotation of the roller pair.

  (2) It is preferable that any one roller of the pair of rollers is urged toward the other roller by an elastic member.

  In this configuration, the recording medium is more reliably held between the roller pair.

  (3) The auxiliary roller is preferably formed in a spur shape.

  Accordingly, when the auxiliary roller presses the recording medium, it is possible to prevent the recorded image from coming into contact with the auxiliary roller and deteriorating.

  (4) The roller facing the recording surface of the recording medium in the roller pair is preferably formed in a spur shape.

  Thereby, when the recording medium is transported, the recorded image is prevented from being deteriorated due to contact with the roller pair.

  According to the present invention, when the recording medium having an image recorded on one surface is sent to the reversal guide, the roller pair sandwiching the recording medium rolls with each other and the auxiliary roller moves on the recording medium. Since the end portion is pressed, the recording medium is reliably sent to the reverse guide portion without increasing the driving force of the roller pair.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings. In addition, this embodiment is only an example of this invention and can be suitably changed in the range which does not change the summary of this invention.

1. Overall configuration and features of this embodiment

  FIG. 1 is an external perspective view of a multifunction machine 10 according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view showing the structure of the printer unit 11 of the multifunction machine 10.

  The multifunction machine 10 is a multi-function device (MFD) including a printer unit 11 and a scanner unit 12 and has a printer function, a scanner function, a copy function, and a facsimile function. The image recording apparatus according to the present invention is implemented as the printer unit 11 of the multifunction machine 10. Accordingly, functions other than the printer function in the multifunction machine 10 are arbitrary.

  As shown in FIG. 1, the lower part of the multifunction machine 10 is a printer unit 11. As shown in FIG. 2, a conveyance path 23 and a reverse guide unit 16 are formed inside the printer unit 11. A recording sheet as a recording medium is conveyed along the conveyance path 23. The printer unit 11 includes a feeding unit 15 that feeds recording paper to the conveyance path 23, a recording unit 24 that records an image on the recording paper, and a paper discharge tray 21 as a paper discharge unit. The multifunction machine 10 according to the present embodiment can record images on both front and back sides of a recording sheet. When an image is also recorded on the back surface of the recording paper, the recording paper having the image recorded on the front surface is returned from the conveyance path 23 to the reverse guide unit 16. That is, the recording sheet is again sent to the conveyance path 23 and turned upside down, and the recording unit 24 records an image on the back side. A feature of the MFP 10 according to the present embodiment is that a path switching unit 41 is provided. The path switching unit 41 reliably and smoothly guides the recording sheet to the reverse guide unit 16 when double-sided recording is performed. The recording sheet on which the image is recorded is discharged to the discharge tray 21. The paper discharge tray 21 is adjacent to the downstream side of the transport path 23 in the transport direction.

  As shown in FIG. 1, the upper part of the multifunction machine 10 is a scanner unit 12. The scanner unit 12 is configured as a so-called flat bed scanner. A document cover 30 is provided as a top plate of the multifunction machine 10. Although not shown in the figure, a platen glass is disposed under the document cover 30. The document is placed on the platen glass and read as an image while being covered with the document cover 30.

  An operation panel 40 is provided on the front upper portion of the multifunction machine 10. The operation panel 40 is a device for operating the printer unit 11 and the scanner unit 12. The multifunction machine 10 also includes a slot portion 43. Various small memory cards, which are storage media, can be loaded in the slot portion 43. For example, when the user operates the operation panel 40 with the small memory card loaded in the slot portion 43, the image data stored in the small memory card is read and recorded on the recording paper.

2. Printer section

  Hereinafter, the internal configuration of the multifunction machine 10, particularly the configuration of the printer unit 11 will be described.

[2-1 Feeding section]

  As shown in FIG. 1, an opening 13 is provided in front of the printer unit 11. The paper feed tray 20 and the paper discharge tray 21 are provided in two upper and lower stages inside the opening 13. As shown in FIG. 2, the feeding unit 15 includes a sheet feeding tray 20, a sheet feeding arm 26 and a sheet feeding roller 25, and a power transmission mechanism 27 for driving the sheet feeding roller 25.

  The paper feed tray 20 stores recording paper. The recording paper stored in the paper feed tray 20 is fed into the printer unit 11. The paper feed tray 20 is disposed on the bottom side of the printer unit 11. A separation inclined plate 22 is provided on the back side of the paper feed tray 20. The separation inclined plate 22 is continuous with the conveyance path 23. The separation inclined plate 22 separates the recording paper that is double-fed from the paper feed tray 20 and guides the uppermost recording paper upward. The conveyance path 23 is bent in a U shape toward the front side after going upward from the separation inclined plate 22. The conveyance path 23 extends from the back side (left side in the figure) to the front side (right side in the figure) of the multifunction machine 10, and communicates with the paper discharge tray 21 via the recording unit 24. Accordingly, the recording paper stored in the paper feed tray 20 is guided to make a U-turn from the lower side to the upper side along the paper conveyance path 23 and reaches the recording unit 24, and image recording is performed by the recording unit 24. Thereafter, the paper is discharged to the paper discharge tray 21.

  FIG. 3 is a partially enlarged sectional view of the printer unit 11.

  As shown in FIG. 3, a paper feed roller 25 is disposed on the upper side of the paper feed tray 20. The paper feed roller 25 supplies the recording paper loaded on the paper feed tray 20 to the transport path 23. The paper feed roller 25 is pivotally supported at the tip of the paper feed arm 26. The paper feed roller 25 is rotationally driven via a power transmission mechanism 27 using a motor (not shown) as a drive source. The drive transmission mechanism 27 has a plurality of gears and is configured by meshing them.

  The paper feed arm 26 is supported by the base shaft 28. A base end portion of the paper feed arm 26 is supported by a base shaft 28 and can be rotated about the base shaft 28 as a rotation center axis. For this reason, the paper feed arm 26 can move up and down so as to be able to contact and separate from the paper feed tray 20. The paper feed arm 26 is urged to rotate downward by its own weight or urged by a spring or the like. For this reason, the paper feed arm 26 normally comes into contact with the paper feed tray 20 and retracts upward when the paper feed tray 20 is inserted and removed. When the paper feeding arm 26 is urged to rotate downward, the paper feeding roller 25 comes into pressure contact with the recording paper on the paper feeding tray 20. In this state, when the paper feed roller 25 is rotated, the uppermost recording paper is fed toward the separation inclined plate 22 by the frictional force between the roller surface of the paper feeding roller 25 and the recording paper. The recording sheet is guided upward after its leading end abuts against the separation inclined plate 22 and is fed along the arrow 14 into the conveyance path 23. When the uppermost recording paper is sent out by the paper feed roller 25, the recording paper immediately below it may be sent out together due to friction or static electricity, but this recording paper is restrained by contact with the separation inclined plate 22. Is done.

  The conveyance path 23 is defined by an outer guide surface and an inner guide surface except for a portion where the recording unit 24 or the like is disposed. For example, the curved portion 17 of the conveyance path 23 on the back side of the multifunction machine 10 is configured by fixing the outer guide member 18 and the inner guide member 19 to the apparatus frame. In this case, the outer guide member 18 constitutes an outer guide surface, and the inner guide member 19 constitutes an inner guide surface. The outer guide member 18 and the inner guide member 19 are arranged to face each other at a predetermined interval. A rotating roller 29 is provided at a location where the conveyance path 23 is bent. The rotating roller 29 is freely rotatable. The roller surface of the rotating roller 29 is exposed to the outer guide surface. Therefore, the recording paper is smoothly transported even at the portion where the transport path 23 is bent.

[2-2 Recording section]

  The recording unit 24 is arranged in the middle of the conveyance path 23 as shown in FIG. The recording unit 24 includes a carriage 38 and an inkjet recording head 39. The ink jet recording head 39 is mounted on the carriage 38. The carriage 38 reciprocates in the main scanning direction (the direction perpendicular to the paper surface in the figure). Note that an ink cartridge is disposed inside the multifunction machine 10 independently of the ink jet recording head 39. FIG. 3 does not show the ink cartridge. Ink is supplied from the ink cartridge to the inkjet recording head 39 through an ink tube. While the carriage 38 is reciprocated, ink is ejected as fine ink droplets from the ink jet recording head 39, whereby an image is recorded on the recording paper conveyed on the platen 42.

[2-3 Inversion guide section]

  The reverse guide unit 16 is connected to the transport path 23. The reverse guide unit 16 is continuous with the downstream portion 36 of the transport path 23 relative to the recording unit 24. The reversing guide unit 16 constitutes a reversing path that guides the recording paper on which an image is recorded on one side onto the paper feed tray 20 again. This inversion path is defined by the first guide surface 32 and the second guide surface 33. In the present embodiment, the first guide surface 32 and the second guide surface 33 are constituted by the surfaces of the guide member 34 and the guide member 35 disposed inside the main body frame of the multifunction machine 10, respectively. The guide members 34 and 35 are opposed to each other at a predetermined interval, and the first guide surface 32 and the second guide surface 33 are obliquely downward from the downstream portion 36 of the transport path 23 toward the paper feed roller 25. It extends.

  Therefore, in the present embodiment, the recording paper on which the image is recorded on the one surface is sent again to the upstream portion 37 of the transport path 23 by the paper feed roller 25. The recording sheet is conveyed in a U shape along the direction of the arrow 14 as described above, and an image is recorded on the other surface by the recording unit 24. In the present embodiment, the reversing guide unit 16 is configured to return the recording paper onto the paper feed tray 20, but the present invention is not limited to this. In short, it is sufficient that the reversing guide unit 16 can connect the downstream side portion 36 and the upstream side portion 37 of the transport path 23, and therefore the recording sheet is closer to the paper feed tray 20 than the upstream side portion 37. Return to

[2-4 Paper transport system]

  As shown in FIG. 3, a conveyance roller 60 and a pinch roller 31 are provided on the upstream side of the conveyance path 23 from the recording unit 24. These are paired, and the pinch roller 31 is disposed so as to be in pressure contact with the lower side of the conveying roller 60. The conveyance roller 60 and the pinch roller 31 pinch the recording paper conveyed through the conveyance path 23 and send it onto the platen 42. Further, a discharge roller 62 and a spur roller 63 are provided on the downstream side of the conveyance path 23 from the recording unit 24. The paper discharge roller 62 and the spur roller 63 pinch the recorded recording paper and transport it further from the transport path 23 to the downstream side in the transport direction (to the paper discharge tray 21 side). The transport roller 60 and the paper discharge roller 62 are driven using the motor as a drive source. The driving of the transport roller 60 and the paper discharge roller 62 is synchronized, and these are driven intermittently. As a result, the recording paper is sent with a predetermined line feed width. Although not shown, the transport roller 60 is provided with a rotary encoder. This rotary encoder detects the pattern of an encoder disk (not shown) that rotates together with the transport roller 60 with an optical sensor. Based on this detection signal, the rotation of the transport roller 60 and the paper discharge roller 62 is controlled.

  The spur roller 63 is in pressure contact with the recorded recording paper. The roller surface of the spur roller 63 is uneven in a spur shape so that the image recorded on the recording paper does not deteriorate. The spur roller 63 is provided so as to be slidable in a direction in which the spur roller 63 is in contact with or separated from the paper discharge roller 62. The spur roller 63 is urged so as to come into pressure contact with the paper discharge roller 62. As a means for urging the spur roller 63 against the paper discharge roller 62, a coil spring is typically employed. When the recording paper enters between the paper discharge roller 62 and the spur roller 63, the spur roller 63 retracts against the biasing force of the coil spring by the thickness of the recording paper. The recording paper is pressed against the paper discharge roller 62, and the rotational force of the paper discharge roller 62 is reliably transmitted to the recording paper. The pinch roller 31 is also elastically biased with respect to the transport roller 60 in the same manner. Therefore, the recording sheet is pressed against the conveying roller 60, and the rotational force of the conveying roller 60 is reliably transmitted to the recording sheet.

  In the multifunction machine 10, the motor serves as a drive source for feeding recording paper from the paper feed tray 20, and transports recording paper positioned on the platen 42 and records recorded recording paper. This is a drive source for discharging to the discharge tray 21. That is, the motor drives the conveyance roller 60 and also drives the paper feed roller 25 via the drive transmission mechanism 27 as described above. Further, the motor drives the paper discharge roller 62 via a predetermined power transmission mechanism. This power transmission mechanism may be constituted by, for example, a gear train, or a timing belt or the like may be used due to the assembly space.

[2-5 Route switching unit]

  FIG. 4 is an enlarged view of a main part in FIG. 3 and shows a cross-sectional structure of the path switching unit 41 in detail. FIG. 5 is a perspective view of the drive mechanism 44 of the path switching unit 41. 6 and 7 are a VI-arrow view and a VII-arrow view in FIG. 5, respectively.

  As shown in FIGS. 3 and 4, the path switching unit 41 is arranged on the downstream side of the recording unit 24 in the transport path 23. Specifically, the path switching unit 41 is disposed on the downstream side in the transport direction at the downstream portion 36, that is, the boundary portion between the transport path 23 and the reverse guide unit 16. The path switching unit 41 includes a roller pair including a first roller 45 and a second roller 46, and an auxiliary roller 47 provided in parallel with the second roller 46. The second roller 46 and the auxiliary roller 47 are attached to the frame 48. The frame 48 extends in the left-right direction of the multifunction machine 10 (the direction perpendicular to the paper surface in FIG. 3). However, the cross-sectional shape of the frame 48 is substantially L-shaped as shown in FIG. 4, thereby ensuring the required bending rigidity of the frame 48.

  As shown in FIGS. 4 and 5, the frame 48 includes eight subframes 49. Each sub-frame 49 is symmetrically arranged in the left-right direction with respect to the center of the multifunction machine 10. Each subframe 49 includes a second roller 46 and an auxiliary roller 47, respectively. Therefore, the frame 48 includes eight second rollers 46 and auxiliary rollers 47, respectively. The second roller 46 and the auxiliary roller 47 are supported by support shafts 50 and 51 (see FIG. 4) provided in each sub-frame 49, and are rotatable about the support shafts 50 and 51. In the present embodiment, the second roller 46 and the auxiliary roller 47 are formed in a spur shape. The auxiliary roller 47 is disposed upstream of the second roller 46 by a predetermined distance in the transport direction. Each second roller 46 is urged downward in FIG. 4 by a spring as an elastic member (not shown). Accordingly, each second roller 46 is always elastically pressed against the first roller 45.

  The first roller 45 is rotated using the motor as a drive source. Although not shown in the drawings, the first roller 45 is connected to the motor via a required drive transmission mechanism. As shown in FIG. 5, the first roller 45 includes a central shaft 52. The central shaft 52 is supported on the main body frame 53 side of the multifunction machine 10. The drive transmission mechanism (not shown) is connected to the central shaft 52. A required bracket may be provided on the central shaft 52. When the bracket is fastened to the main body frame 53 side with, for example, screws, the center shaft 52 is reliably supported by the main body frame 53.

  A second roller 46 is placed on the first roller 47. The first roller 45 may be formed in a single elongated cylindrical shape, and eight rollers may be arranged to face the second rollers 47, respectively. The first roller 45 is rotated forward and reverse by the motor. The recording paper conveyed along the conveyance path 23 is sandwiched between the first roller 45 and the second roller 46. When the first roller 45 rotates in the forward direction, the recording sheet is conveyed downstream in the conveying direction while being sandwiched between the first roller 45 and the second roller 46, and is discharged to the paper discharge tray 21. On the other hand, when the first roller 45 rotates in the reverse direction, the recording sheet is returned to the upstream side in the transport direction while being sandwiched between the first roller 45 and the second roller 46.

  As shown in FIGS. 5 to 7, the drive mechanism 44 includes a driven gear 54 provided on the central shaft 52, a drive gear 55 that meshes with the driven gear 54, and a guide plate 57 in which the drive gear 55 is connected via a pin 56. And have. The guide plate 57 is illustrated only in FIG. The guide plate 57 includes a rotation drive shaft 58, and the rotation drive shaft 58 is driven using the motor as a drive source. As shown in FIG. 7, a guide groove 59 is provided in the guide plate 57. The guide groove 59 is formed in an annular shape around the rotation drive shaft 58. Specifically, the guide groove 59 includes a small arc portion 69 and a large arc portion 70 centering on the rotation drive shaft 58, a connecting groove 72 that connects one end of the small arc portion 69 and one end of the large arc portion 70, And a connecting groove 73 that connects the other end of the small arc portion 69 and the other end of the large arc portion 70. The pin 56 is fitted in the guide groove 59 and is slidable along the fitting groove 59.

  As shown in FIGS. 5 and 6, the driven gear 54 includes a tooth portion 64 and a flange portion 65. The tooth portion 64 is configured as an involute gear centered on the central shaft 52. The tooth portion 64 is fitted into the central shaft 52 and can rotate around the central shaft 52. The flange portion 65 is formed integrally with the tooth portion 64 and is connected to the frame 48. Therefore, when the tooth portion 64 rotates, the frame 48, the sub frame 49, the second roller 46, and the auxiliary roller 47 rotate integrally with the central shaft 52 as the rotation center.

  The drive gear 55 is rotatably supported on the support shaft 66. The support shaft 66 is provided on the main body frame 53. The drive gear 55 includes a tooth portion 67 and an arm 68, and the pin 56 protrudes from the arm 68. The tooth portion 67 is configured as an involute gear centered on the support shaft 66 and meshes with the tooth portion 64. As the tooth portion 67 rotates, the tooth portion 64 rotates, and as a result, the frame 48, the sub-frame 49, the second roller 46, and the auxiliary roller 47 rotate integrally around the center shaft 52 as a rotation center.

  FIG. 8 is a perspective view of the drive mechanism 44 of the path switching unit 41 in a state in which the frame 48, the sub frame 49, the second roller 46, and the auxiliary roller 47 are rotated. 9 and 10 are respectively an IX-arrow view and an X-arrow view in FIG. FIG. 11 is an enlarged view of a main part in FIG. 3 and shows a state in which the path switching unit 41 is rotated about the central axis 52.

  As shown in FIG. 7, when the guide plate 57 rotates, the pin 56 moves relatively along the guide groove 59, and in particular, when sliding along the connecting grooves 72 and 73, the pin 56 is The guide plate 57 moves in the radial direction. For this reason, when the guide plate 57 is rotated clockwise (in the direction of the arrow 82) in FIG. 7, the pin 56 sequentially moves to the connecting groove 73, the large arc portion 70, and the connecting groove 72. Therefore, the drive gear 55 rotates clockwise in FIG. As a result, the driven gear 54 rotates counterclockwise around the central axis 52 in FIG. As described above, since the driven gear 54 is connected to the frame 48, the rotation of the driven gear 54 causes the frame 48, the sub frame 49, the first roller 46, and the auxiliary roller 47 to rotate around the central shaft 52. It rotates integrally, and it will be in the state which FIG. 8 thru | or FIG. 10 shows. When the guide plate 57 is rotated counterclockwise (in the direction of the arrow 83) in FIG. 10 from the state shown in FIGS. 8 to 10, the pin 56 is connected to the connecting groove 72, the large arc portion 70, and the connecting groove. 73 in order. Therefore, the drive gear 55 rotates counterclockwise in FIG. As a result, the driven gear 54 rotates clockwise around the central axis 52 in FIG.

  At this time, the frame 48, the sub frame 49, the second roller 46, and the auxiliary roller 47 rotate around the central shaft 52. Therefore, as shown in FIGS. 4 and 11, the second roller 46 rolls on the peripheral surface of the first roller 45. In the present embodiment, the posture of the path switching unit 41 as shown in FIG. 4 is defined as “recording medium discharge posture”, and the posture of the path switching unit 41 as shown in FIG. 11 is “recording medium reverse posture”. Defined. When the path switching unit 41 is in the recording medium discharge posture, the recording paper transported along the transport path 23 is sent to the paper discharge tray 21 as it is. Further, when the path switching unit 41 is in the recording medium reversing posture, the recording paper 74 is returned to the upstream side in the transport direction and guided to the reversing guide unit 16 as shown in FIG. When the path switching unit 41 changes from the recording medium ejection posture to the recording medium reverse posture, the auxiliary roller 47 presses the recording paper 74 and guides it to the reverse guiding portion 16 side.

[2-6 Guide section]

  As shown in FIGS. 4 and 11, the guide portion 76 is provided on the downstream side in the transport direction with respect to the first roller 45 and the second roller 46. A support plate 75 is attached to the main body frame 53, and a guide portion 76 is provided on the support plate 75. The guide portion 76 includes a base portion 77 fixed to the lower surface of the support plate 75 and a guide roller 78 supported by the base portion 77. The base 77 includes a support shaft 79, and the guide roller 78 is rotatably supported by the support shaft 79. In the present embodiment, the guide roller 78 is formed in a spur shape.

  The guide portion 76 is disposed at a predetermined position. That is, the guide unit 76 contacts the recording surface of the recording sheet 74 when the first roller 45 and the second roller 46 are rotated in the reverse direction and the recording sheet 74 is sent to the reverse guiding unit 16. Further, the guide portion 76 does not contact the recording paper 74 when the first roller 45 and the second roller 46 are rotated forward and the recording paper 74 is sent to the reverse guiding portion 16. Specifically, the guide portion 76 is provided at a position where it does not come into contact with an imaginary line connecting the contact point between the first roller 45 and the second roller 46 and the contact point between the paper discharge roller 62 and the spur roller 63.

  As will be described later, the recording paper 74 is sent to the reversing guide unit 16 with its transport direction changed. The portion of the recording paper 74 on the downstream side of the first roller 45 and the second roller 46 tends to change its direction in a direction parallel to the reverse guide portion 16 due to the rigidity of the recording paper 74. However, the guide roller 78 comes into contact with the recording surface of the recording paper 74 and bends the recording paper 74. As a result, the recording paper 74 is wound around the first roller 45 and the second roller 46, so that the recording paper 74 is surely sent to the reverse guide unit 16.

3. Advantages of MFP according to this embodiment

  As shown in FIG. 3, the recording paper drawn from the paper feed tray 20 is conveyed along the direction of the arrow 14, and an image is recorded on one surface by the recording unit 24. This recording sheet is sandwiched between the first roller 45 and the second roller 46 of the path switching unit 41. When an image is recorded only on one side of the recording paper, the path switching unit 41 assumes the recording paper ejection posture as shown in FIG. Then, the first roller 45 and the second roller 46 are rotated forward, whereby the recording paper is discharged to the paper discharge tray 21.

  When an image is recorded on the other side of the recording paper, the recording paper is conveyed as follows. First, the path switching unit 41 assumes a recording paper discharge posture, and the first roller 45 and the second roller 46 perform normal rotation while sandwiching the recording paper. Thereby, the recording paper is conveyed to the paper discharge tray 21 side. When the rear end portion of the recording paper reaches a specified position upstream of the auxiliary roller 47, that is, when the rear end portion 81 of the recording paper 74 reaches the auxiliary roller 47 as shown in FIG. The path switching unit 41 assumes the recording sheet reversal posture. Thereby, the rear end portion 81 of the recording paper 74 is pressed by the auxiliary roller 47 and directed toward the reverse guide portion 16. By the reverse rotation of the first roller 45 and the second roller 46, the recording sheet 74 is sent to the reverse guide unit 16 with the conveyance direction changed.

  When the path switching unit 41 changes to the recording paper reversing posture, the path switching unit 41 swings about the support shaft 50 of the first roller 45. That is, the second roller 46 rolls on the circumferential surface of the first roller 45 while holding the recording paper 74, and the auxiliary roller 47 presses the recording paper 74. In other words, the second roller 46 rolls on the peripheral surface of the first roller 45 so that the recording paper 74 is wound around the peripheral surface of the first roller 45. As a result, the orientation of the recording paper 74 can be easily changed to the reversal guide portion 16.

  The recording paper 74 sent to the reversal guide unit 16 is sent to the transport path 23 by the paper feed roller 25 and sent again to the recording unit 24. Since the transport path 23 is formed in a U-shape as described above, an image is recorded on the other surface of the recording paper 74. The recording paper 74 on which images are recorded on both sides is sandwiched between the first roller 45 and the second roller 46 of the path switching unit 41, and is sent to the paper discharge tray 21 when they are rotated forward.

  According to the multifunction machine 10 according to the present embodiment, the second roller 46 rolls on the circumferential surface of the first roller 45 when the recording sheet 74 having an image recorded on one side is sent to the reverse guide unit 16. The auxiliary roller 47 presses the rear end portion 81 of the recording paper 74 while moving and winding the recording paper 74 around the first roller 45. Therefore, even if the driving force of the first roller 45 and the second roller 46 is not increased, the recording paper 74 is securely held by the first roller 45 and the second roller 46 and sent to the reverse guide unit 16. Since it is not necessary to increase the driving force of the first roller 45 and the second roller 46, it is not necessary to employ a large motor or the like to convey the recording paper 74, and the recording paper 74 is prevented from being damaged. At the same time, downsizing of the multifunction machine 10 is realized.

  In the present embodiment, since the second roller 46 is elastically biased toward the first roller 45, the recording paper 74 is more securely sandwiched and conveyed by the first roller 45 and the second roller 46. There is an advantage.

  Moreover, since the auxiliary roller 47 and the second roller 46 are formed in a spur shape, when the auxiliary roller 47 presses the recording paper 74 and when the recording paper 74 is discharged to the paper discharge tray 21, It is possible to prevent the image recorded on the recording paper 74 from deteriorating due to contact with the auxiliary roller 47 and the second roller 46.

  In the present embodiment, the second roller 46 rolls on the circumferential surface of the first roller 45 when the path switching unit 41 changes its posture, but the first roller 45 rolls on the circumferential surface of the second roller 46. It may be configured to. In the present embodiment, the second roller 46 is urged toward the first roller 45 by the elastic member, but the first roller 45 may be elastically urged toward the second roller 46.

FIG. 1 is an external perspective view of a multifunction peripheral according to an embodiment of the present invention. FIG. 2 is a vertical cross-sectional view of a multifunction peripheral according to an embodiment of the present invention. FIG. 3 is a partial enlarged cross-sectional view of the multifunction peripheral according to the embodiment of the present invention. FIG. 4 is an enlarged view of a main part in FIG. FIG. 5 is a perspective view of the drive mechanism of the path switching unit according to the embodiment of the present invention. 6 is a view taken along the line VI--arrow in FIG. 7 is a partial cross-sectional view taken along arrow VII in FIG. FIG. 8 is a perspective view of the drive mechanism of the path switching unit according to the embodiment of the present invention. FIG. 9 is an IX-arrow view in FIG. FIG. 10 is a partial cross-sectional view taken along the line X-arrow in FIG. FIG. 11 is an enlarged view of a main part in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Multifunction machine 11 ... Printer part 15 ... Feeding part 16 ... Inversion guide part 20 ... Paper feed tray 21 ... Paper discharge tray 24 ... Image recording unit 36 .. -Downstream part 37 ... Upstream part 41 ... Path switching unit 44 ... Drive mechanism 45 ... First roller 46 ... Second roller 47 ... Auxiliary roller 53 ... Body frame 63 ... spur roller 74 ... recording paper 80 ... recording surface 81 ... rear end

Claims (4)

A transport path for transporting the recording medium;
A feeding section for sending a recording medium to the conveyance path;
A recording unit that is provided in the conveyance path and records an image on a recording medium;
A paper discharge unit provided on the downstream side in the transport direction from the transport path;
A reversing guide portion for connecting a downstream side portion and an upstream side portion of the recording path to the recording medium so as to reverse the recording medium;
The recording medium is provided at the downstream portion, and the recording medium can be fed forward by sandwiching the recording medium and rotated forward, and the recording medium can be rotated by sandwiching the recording medium and reversed. A roller pair capable of being sent to the reversing guide unit, and an auxiliary roller disposed on the upstream side in the transport direction with respect to the roller pair. An image recording apparatus having a path switching unit that swings between a recording medium discharge attitude and a recording medium inversion attitude.   The image recording apparatus according to claim 1, wherein any one of the rollers is urged toward the other roller by an elastic member.   The image recording apparatus according to claim 1, wherein the auxiliary roller is formed in a spur shape. 4. The image recording apparatus according to claim 1, wherein a roller facing the recording surface of the recording medium in the pair of rollers is formed in a spur shape. 5.

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