JP2005247557A - Sheet carrying device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet carrying device capable of reducing an occupying space of a sheet reversing path; and an image forming device having this sheet carrying device. <P>SOLUTION: This sheet carrying device has a sheet reversing means for reversing its obverse and reverse by rotating a sheet by 180 degrees. A regulating plate is arranged in a sheet carrying part of the sheet reversing means. Thus, since the sheet can be reversed while curving an end part of the sheet by arranging the regulating plate in a reversing carrying part for reversing the sheet, the occupying volume of the sheet reversing part can be reduced. As a result, the effect of reducing even the volume of the whole device having the sheet reversing part can be expected. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a sheet conveying apparatus that reverses the front and back of a sheet and an image forming apparatus including the sheet conveying apparatus.

  A conventional sheet reversing and conveying mechanism employs a mechanism that reverses the front and back of the sheet by switching back and switching the leading and trailing edges of the sheet. At this time, since the front and back with respect to the conveyance direction of the sheet are reversed, it is necessary to consider the front and rear direction of the paper when performing the second side printing at the time of duplex printing in the image forming apparatus.

  In order to solve this problem, an inversion mechanism has been proposed in which the sheet is rotated 180 ° in a direction orthogonal to the conveyance direction axis and the left and right sides of the sheet are interchanged. Further, a mechanism has been proposed in which the front and back of the sheet are reversed while the sheet is spirally rotated by two pairs of belt-shaped members (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 2002-20000

  However, in the sheet reversing mechanism by changing the left and right of the sheet in the conventional invention and the sheet reversing and conveying mechanism by the belt pair, a volume corresponding to the rotation radius having the diameter of the sheet width is necessary to rotate the sheet width. . For this reason, there has been a problem that the entire apparatus using the sheet reversing mechanism becomes large.

  SUMMARY An advantage of some aspects of the invention is that it provides a sheet conveying device capable of reducing the space occupied by a sheet reversing path and an image forming apparatus including the sheet conveying device.

  The present invention is characterized in that in the sheet conveying apparatus provided with a sheet reversing means for reversing the front and back of the sheet by rotating the sheet by 180 degrees, a regulation plate is provided in the sheet conveying portion of the sheet reversing means.

  By providing the regulating plate in the reversing conveyance unit for reversing the sheet in this way, the sheet can be reversed while curving the end of the sheet, so that the volume occupied by the sheet reversing unit can be reduced. As a result, an effect of reducing the volume of the entire apparatus including the sheet reversing unit can be expected.

  The sheet reversing and conveying apparatus of the present invention has a sheet conveying means to the sheet reversing and conveying path and a mechanism for spirally conveying the sheet in the sheet reversing and conveying path. As a result, it is possible to continuously reversely convey the sheets without stopping subsequent sheets or increasing the sheet interval. In addition, when the sheet is reversed, the sheet conveyance speed component in the direction orthogonal to the conveyance direction can be changed according to the previously detected sheet size, so that the space of the sheet reverse conveyance mechanism can be reduced and the downstream side can be reduced without complicated control. The sheet can be delivered to the conveying means.

  Further, since the reversing path is curved, it is possible to reduce the space required for reversing the sheet.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1>
(Image forming device incorporating sheet reversing mechanism)
Hereinafter, a sheet reversing / conveying mechanism 1 according to an embodiment of the present invention and a copying machine 2 as an example of an image forming apparatus including the sheet reversing / conveying mechanism 1 in a main body 3 will be described with reference to FIGS. .

  Further, the sheet conveying apparatus according to the embodiment of the present invention can be equipped not only in a copying machine but also in the main body of a facsimile, a printer, or a composite device thereof, and is provided only in the main body 3 of the copying machine 2. It is not limited to being done.

  Further, the sheet includes plain paper, a thin resin sheet that is a substitute for plain paper, a postcard, a cardboard, a sealed letter, a plastic thin plate, and the like.

  The copying machine 2 includes a main body 3 including a plurality of sheet supply decks 15 and a sheet supply cassette 16. The sheets S of different sizes respectively stacked and stored in the sheet supply deck 15 and the sheet supply cassette 16 are selectively fed to the image forming unit 11.

  The sheets S stacked and stored in the sheet supply deck 15 and the sheet supply cassette 16 are sequentially fed from the uppermost sheet to the sheet feeding path 27 by the feeding roller 17. The sheet feeding path 27 guides the sheet from the sheet supply cassettes 15 and 16 to the image forming unit 11 described later.

  The sheets S fed by the feeding roller 17 are separated one by one by the separation roller pair 18 and fed to the registration roller pair 19.

  When the leading edge of the sheet S fed by the separation roller pair 18 hits the nip of the registration roller pair 19, a predetermined loop is formed to correct the skew state.

  The sheet S whose skew state has been corrected is transferred and charged with the photosensitive drum 4 of the image forming unit 11 by the registration roller pair 19 which starts rotating at the timing of aligning the position with the toner image on the rotating photosensitive drum 4. The toner image on the photosensitive drum 4 is transferred to the sheet S by the transfer charger 12.

  In the copying machine 2, an image of a document set on the platen glass 5 is read by a CCD 10 by an optical system including an illumination lamp 6, reflecting mirrors 7 and 8, a zoom lens 9, and the like, and undergoes desired image processing. Laser light is irradiated onto the photosensitive drum 4 by a laser scanner. As a result, an electrostatic latent image is formed on the photosensitive drum 4, and the electrostatic latent image is visualized by the black toner supplied from the developing device 14 and becomes a toner image.

  The sheet S after the transfer of the toner image in the image forming unit 11 is sent to the fixing unit 20 by the conveying belt 13, and the toner image is fixed to the sheet by the fixing unit 20.

  The sheet S on which the toner image is fixed is conveyed to the sheet reversing mechanism 1. The sheet reversing mechanism 1 includes two pairs of ring-shaped rotating members 103 and 104, plate-like members 101 and 102, and a restriction plate 109 indicated by a dotted line in FIG. The plate-shaped members 101 and 102 are connected to the ring-shaped rotating members 103 and 104 by members 105 and 106, respectively.

  The plate-like members 101 and 102 are provided with roller pairs 107 and 108 as sheet conveyance driving means, and the sheet S can be carried into and out of the plate-like member.

  The aforementioned ring-shaped member has a circular shape with a diameter R1, and is configured to have a diameter slightly larger than the maximum width of the sheet size that can be conveyed by the image forming apparatus of the present embodiment. Further, the width of the plate-like members 101 and 102 in the direction orthogonal to the sheet conveying direction is R3, which is smaller than the minimum width of the sheet size that can be conveyed by the image forming apparatus of the present embodiment, and the sheet S to be reversed. Any width that can be held is acceptable.

  On the other hand, the regulation plate 109 is configured in an elliptical column shape, and the major axis of the ellipsoid is R1 and the minor axis is R2. At this time, the size of each member is determined so that R3 <R2 <R1.

  Although the size of the restriction plate 109 of the present embodiment is fixed for cost reduction, a configuration in which the size of the elliptical column of the restriction plate 109 is changed and the size is changed according to the width of the sheet S is adopted. Anyway.

The sheet S is conveyed onto the plate-like members 101 and 102 by the roller pairs 107 and 108. Thereafter, the plate-like members 101 and 102 are rotated 180 ° together with the ring-like members 103 and 104 to reverse the front and back. At this time, since the width of the sheet S is larger than that of the plate-like members 101 and 102, the sheet end protruding from the plate-like members 101 and 102 is reversed while being curved along the regulation plate 109. (Figure 3)
The sheet S that has been turned upside down is discharged from the sheet turning mechanism 1 by the roller members 107 and 108.

  When the sensor 22 detects the leading edge of the sheet S whose front and back are reversed, the roller pair 25 starts to rotate. At this time, the flapper 24 is switched so that the sheet S is conveyed in the direction of the roller pair 25. Thereafter, the sheet S passes through the conveyance path 27 by the roller pair group 26 and is conveyed again to the image forming unit by the registration roller pair 19.

  The sheet S on which the toner image is placed on the back surface is again carried into the sheet reverse conveyance mechanism 1 and passes through the sheet reverse conveyance mechanism 1 as it is without rotation of the plate-like members 101 and 102.

  When the sensor 22 detects the leading edge of the sheet S discharged from the sheet reverse conveyance mechanism 1, the discharge roller pair 23 starts to rotate in the direction in which the sheet S is discharged onto the discharge tray 37. At this time, the flapper 24 is switched in such a direction that the sheet S is conveyed in the direction of the discharge roller pair 23.

<Embodiment 2>
(Turning reversing device using two belt pairs)
Based on FIG. 4, a sheet reversal conveyance mechanism using a turning device will be described.

  The pair of endless belts 303 and 304 are spanned so as to intersect with the rotary driving bodies 301 and 302, respectively. The sheet carried into the sheet reversing and conveying mechanism is conveyed in the direction of the arrow in the figure, and is conveyed according to the intersecting endless belt pair at this time, so that the front and back are reversed. A reversal region portion of the sheet on which the endless belt pair 303 and 304 is stretched is covered with a regulation plate 305.

  As described in the first embodiment, the restricting plate 305 has an elliptical column structure, and the relation of R2 <R1 is established, where R1 is the major axis of the ellipse and R2 is the minor axis. If the width of the sheet is in a range where the width in the direction perpendicular to the conveying direction is larger than R2 and smaller than R1, the sheet end radius is rotated along the inner side of the elliptic cylinder, thereby rotating the sheet radius of rotation. Can be reduced.

  The present invention can be applied not only to a copying machine but also to a sheet conveying apparatus that can be installed in a main body of a facsimile, a printer, or a composite device thereof.

1 is a front sectional view of an image forming apparatus provided with a main body of a sheet conveying device according to the present invention. It is sectional drawing of the inversion mechanism used in Embodiment 1 of a sheet inversion conveyance mechanism. FIG. 3 is a cross-sectional view in a direction orthogonal to the conveyance surface in the first embodiment of the sheet reverse conveyance mechanism. It is sectional drawing of the inversion mechanism used in Embodiment 2 of a sheet inversion conveyance mechanism.

Explanation of symbols

S sheet R1 long diameter length of elliptical columnar regulating plate R2 short diameter length of elliptical columnar regulating plate R3 width of plate member of sheet reverse conveying mechanism 1 sheet reverse conveying mechanism 2 copier (image forming apparatus)
3. Copier body, sheet transport device body (image forming device body, sheet transport device body)
4 Photosensitive drum 5 Platen glass 6 Illumination lamp 7, 8 Reflection mirror 9 Zoom lens 10 CCD
DESCRIPTION OF SYMBOLS 11 Image forming means 12 Transfer charging device 13 Conveying belt 14 Developing device 15 Sheet supply deck 16 Sheet supply cassette 17 Feeding roller 18 Separating roller pair 19 Registration roller pair 20 Fixing means 21 Sheet reversing conveyance unit entrance sensor 22 Sheet reversing conveyance unit exit sensor 23 discharge roller 24 discharge path switching flapper 25 transport path roller pair in duplex mode 26 transport roller pair group in duplex mode 27 transport path in duplex mode 37 discharge tray 101, 102 plate-like members 103, 104 of sheet reversal transport mechanism Ring-shaped rotating member 105, 106 of the sheet reverse conveying mechanism 105, 106 Member for connecting the plate-shaped member to the ring-shaped member 107, 108 A pair of the sheet carrying-in and unloading rollers to the sheet reverse conveying mechanism 109 Restriction of the sheet reverse conveying mechanism Board 301,3 02 Rotating drive 303, 304 Endless belt 305 Restriction plate

Claims (5)

In a sheet conveying apparatus provided with sheet reversing means for reversing the front and back of the sheet by rotating the sheet 180 degrees,
A sheet conveying apparatus, wherein a restriction plate is provided in a sheet conveying portion of the sheet reversing means.   The sheet reversing means is formed of two plate-like members, conveys the sheet with a roller pair provided between the two plate-like members, and rotates the plate-like member by 180 degrees, thereby The sheet conveying apparatus according to claim 1, wherein the front and back are reversed.   The sheet conveying apparatus according to claim 2, wherein a width of the plate-like member in a direction orthogonal to the sheet conveying direction is narrower than the width of the sheet to be reversed.   The sheet conveying apparatus according to claim 1, wherein the sheet reversing unit is formed by crossing two belts by 180 degrees.   An image forming apparatus comprising: the sheet conveying apparatus according to claim 1; and an image forming unit that forms an image on a sheet conveyed by the sheet conveying apparatus.

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