JP2006193317A - Sheet inversion device, and image forming device having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent jamming or skewing by rapidly and reliably pressing tips of sheets against a resist roller in a U-turn conveying device of the sheets. <P>SOLUTION: A sheet inversion device comprises a paper feed means which separates only one sheet out of stacked sheets and conveys it to a downstream process, a guide means to guide the sheet conveyed from the paper feed means downstream, a sheet direction changing means having a sheet pressing shape which is arranged in the middle of the guide means, rockingly supported between the first position as the waiting position and the second position moved in the conveying path widening direction by the pressure caused by the flexibility of the sheet while the sheet is direction-changed downward during the conveyance of the sheet, and works to press the sheet downward on the upstream side of the widened conveying path at the second position, and a skew correction means to correct the skew of the sheet which is direction-changed by the sheet direction changing means. Further, an image forming device of the present invention has this sheet inversion device. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sheet reversing apparatus that feeds one sheet of stacked sheets and changes the direction toward a downstream process, and an image forming apparatus including the sheet reversing apparatus.

  A conventional sheet reversing device, when separating only one sheet from a stack of stacked sheets and transporting it in the downstream process, provides a conveying force by pinching a sheet to a pair of rollers such as a so-called intermediate roller, and a sheet reversing path. Some of them are transported along a paper guide that forms a sheet. (For example, refer to Patent Document 1). Hereinafter, a conventional paper reversing device will be described with reference to FIGS. 4, 5, and 6.

  FIG. 4 is a schematic configuration diagram showing an internal configuration of a laser printer equipped with a conventional paper transport device (paper reversing device). The laser printer 210 shown in this figure is composed of an upper structure portion 210a and a lower structure portion 210b. The upper structure portion 210a is attached to the lower structure portion 210b by a hinge 211 so as to be opened and closed.

  An image forming unit is accommodated in the upper structure unit 210a, and a belt-like photoconductor 212 is installed at a substantially central portion thereof. Around the photoconductor 212, a charger 213, a developing device 214, a transfer device 215, a cleaning device 216, and the like are arranged in the driving direction of the photoconductor 212 indicated by arrows in the drawing. An optical writing device 217 is disposed above these members. Further, a fixing machine 224, a paper discharge unit 236, and the like are provided in the upper structure unit 210a.

  The lower structure unit 210b is a paper transport device (paper reversing device) that supplies paper to the image forming unit. The paper transport device includes a paper feed mechanism 219, an intermediate roller 221, a registration roller 222, and the like. An intermediate sensor 231 for detecting the conveyed paper is provided near the upstream side of the intermediate roller 221 in the paper conveyance direction, and a registration sensor 235 is provided in front of the registration roller 222. A paper cassette 218 is attached to the paper transport device (paper reversing device).

  The operation of the laser printer 210 will be schematically described. The photoconductor 212 is driven in the direction of the arrow, that is, counterclockwise in the drawing, and the surface thereof is uniformly charged by the charger 213. The laser beam L from the optical writing device 217 based on the print information is irradiated to form an electrostatic latent image. This latent image is visualized by toner when passing through the developing device 214. On the other hand, the uppermost sheet of the sheet bundle P stored in the sheet feeding cassette 218 is sent out in the direction of arrow A by the sheet feeding roller 220 of the sheet feeding mechanism 219. The sheet is guided by the guide plate 230 and conveyed to the registration roller 222 via the intermediate roller 221. Then, the registration roller 222 takes out the transfer timing of the image formed by the image forming unit and sends it out. The toner image on the photoreceptor 212 is transferred onto the sheet by the action of the transfer unit 215. The sheet on which the toner image has been transferred is guided by the conveyance guide 223 and guided to the fixing device 224, and is heated and pressurized when being nipped between the heating roller 225 and the pressure roller 226 and conveyed. As a result, the toner image is fixed on the paper. The sheet exiting the fixing device 224 is conveyed by the sheet discharge roller 227, guided to the sheet discharge unit 236 by the switching claw 228, and discharged outside the apparatus in the direction of arrow B. Note that the residual toner is removed from the photosensitive member 212 after the toner image is transferred by the cleaning device 216, and thereafter, the charge is removed by the static eliminator 229.

  FIG. 5 shows timings related to the driving timing of the paper feed roller 220, the intermediate roller 221 and the registration roller 222 and the paper detection timing by the intermediate sensor 231 and the registration sensor 235 in this paper conveyance device (paper reversing device). A chart is shown. As shown in this figure, when the sheet feeding roller 220 is driven (turned on) and the sheet is fed, the intermediate sensor 231 detects (turns on) the leading edge of the sheet. The driving of the intermediate roller 221 is stopped (turned off) in synchronization with the detection of the leading edge of the sheet by the intermediate sensor 231. Then, the leading edge of the sheet hits the intermediate roller 221 and is prevented from progressing. At this time, since the paper feed roller 220 is still driven (ON), the paper is bent between the paper feed roller 220 and the intermediate roller 221, that is, a loop is generated. Due to the waist of the paper, a force to return the loop to the original works on the paper, and the front end of the paper follows the intermediate roller 221 to correct the skew (skew) of the paper. The intermediate roller 221 is stopped (turned off) at the leading edge detection timing of the intermediate sensor 231 and then restarted (turned on) after a predetermined time has elapsed. On the other hand, the feed roller 220 is stopped (turned off) when a predetermined time has elapsed after the start of driving. Thereafter, the driving of the intermediate roller 221 is stopped (turned off) at the timing of detection of the leading edge of the sheet by the registration sensor 235, and the driving of the registration roller 222 is started (on) and the driving of the intermediate roller 221 is restarted (turned on). These controls can be performed by the control means of the laser printer main body. In this conventional example, in addition to the skew correction by the intermediate roller 221, the skew correction of the sheet is performed again by the registration roller 222.

FIG. 6 is a perspective view illustrating a state in which the sheet is conveyed to the intermediate roller. As described above, when the leading edge of the paper P1 hits the intermediate roller 221 whose driving is stopped, the paper feeding roller 220 continues to be driven, so that the paper P1 bends as shown by a one-dot chain line in the drawing. At this time, in the sheet conveying apparatus of the present embodiment, as shown in FIG. 7, the guide plate 230 a on the outer side of the curve among the guide plates 230 a and 230 b for guiding the sheet conveying path is arranged at the upper end by the shaft 233. The frame 232 is pivotally supported and is rotatably supported. Accordingly, the leading end is pushed by the bent paper P1 by hitting the intermediate roller 221 and swings in the direction of the arrow U. The guide plate 230 swings to absorb the paper loop, and the weight of the guide plate 230 is applied to the paper, acting as a force for pushing the leading edge of the paper P1 toward the intermediate roller 221. Therefore, the skew correction of the sheet by the intermediate roller 221 can be made more reliable.
Japanese Patent No. 3372323 (pages 4 to 5, FIGS. 1 to 4)

  However, paper reversal by the paper transport device (paper reversing device) having the above-described configuration is such that the rotation shaft 233 of the guide plate 230a is closer to the intermediate roller 221 in the transport path on the upstream side of the intermediate roller 211 performing the registration operation, that is, downstream. The loop space is on the upstream side of the shaft 233. In other words, the loop space is relatively close to the paper feed unit (paper feed roller 220), and the distance to the next-stage transport unit (intermediate roller 221) is relatively long. Thus, when there is a loop space on the upstream side (relatively close to the paper feeding means), most of the conveying force of the paper feeding means (paper feeding roller 220) is absorbed by the growth of the paper loop in the loop space. On the other hand, in the loop space, a paper loop grows in the loop portion of the guide plate 230, and the conveyance resistance increases due to the resistance against which the paper is pressed against the guide plate 230, so that the next-stage conveyance means (intermediate roller 221). The force for pushing into the nip point, that is, the conveying force, is lost and weakened. At that time, the leading edge of the sheet has a relatively high degree of freedom and may have an unstable posture because the conveying force is not sufficiently transmitted because the distance to the conveying means of the next stage may be long on the downstream side of the loop. As a result of the canceling of the conveyance force in this way, the force for pushing the sheet into the next-stage conveyance unit (intermediate roller 221) is weak and the leading end behavior of the sheet becomes unstable. There was a problem that the paper could not reach the conveying means of the stage and jammed.

  In order to solve the above-described problem, the sheet reversing device of the present invention separates only one sheet from the stacked sheets and conveys it in the downstream process, and the sheet conveyed from the sheet feeding unit downstream. The guide means for guiding, the first position which is arranged in the middle of the guide means, and the first position which is a standby position, and the paper is moved by the waist of the paper while being turned downstream, and moved in the direction of widening the conveyance path. A paper direction changing means having a paper pushing shape which is supported so as to be swingable between the second position and which acts to push the paper to the downstream side on the upstream side of the widened conveying path when in the second position; And skew correction means for correcting the skew of the paper whose direction has been changed by the paper direction changing means. The image forming apparatus of the present invention includes such a sheet reversing device.

  Thus, in the paper reversing device of the present invention, when the paper direction changing means is at the second position, the widened conveyance path serving as the loop space is on the downstream side, and the conveying force of the paper feeding means is effectively transmitted to the leading edge of the paper. Therefore, the leading edge of the sheet can be surely pushed into the skew feeding correcting means, jamming can be prevented, and skew feeding correction with high accuracy can be performed. Further, when the paper direction changing means is at the second position, the paper pushing shape pushes the paper downstream, so that the skew correction can be surely performed. Further, since the paper reaches the skew correction means at the shortest distance without forming a loop on the paper until the leading edge of the paper reaches the skew correction means, the skew correction can be started in a short time. Therefore, when this sheet direction changing device is used in an image forming apparatus or the like, the productivity (throughput) of image formation can be increased.

  The image forming apparatus of the present invention includes the above-described sheet reversing device. As a result, it is possible to provide an image forming apparatus capable of obtaining a highly reliable, high speed, and high quality printing result without jamming or skew feeding.

  A sheet reversing device according to the present invention includes a sheet feeding unit that separates only one sheet from stacked sheets and conveys the sheet in a downstream stroke, a guiding unit that guides the sheet conveyed from the sheet feeding unit to the downstream, A first position that is arranged in the middle and is a standby position when there is no paper, and a second position that is pushed by the waist of the paper while moving the paper downstream while the paper is transported and moved in a direction that widens the transport path And a paper direction changing means which acts to push the paper downstream on the upstream side of the widened conveying path when in the second position, and the direction is changed by the paper direction changing means. Skew correction means for correcting the skew of the printed paper. Hereinafter, an ink jet printer as an example of an image forming apparatus to which a paper reversing device of the present invention is applied will be described with reference to the drawings.

  1 and 2 are sectional views of the ink jet printer 1. FIG. 2 is an enlarged view of a main part of the sheet reversing device of the present embodiment in FIG. In FIG. 1, an ink jet printer 1 includes a main body case 2, a cassette 3, a registration roller pair 4, a print head 5, a platen 6, a paper discharge roller pair 7, a paper discharge tray 8, a paper supply roller 9, an inner guide 10, and a flapper guide. 11, an upper guide 12, a separation plate 13, a swing arm 14, and the like.

  The main body case 2 supports the entire inkjet printer 1. Further, the main body case 2 receives the sheet S1 separated by the action of the sheet feeding roller 9 as the sheet feeding means and the separation plate 13, and guides the outside of the first conveyance path described later as a part of the guiding means. At the same time, a conveyance path on the upstream side of the flapper guide 11 which is a sheet direction changing means is formed. The cassette 3 is configured to be detachable from the main body case 2 and stacks the sheet bundle S. The upper surface of the sheet bundle S is configured such that the sheet feeding roller 9 always contacts the sheet amount following the sheet amount. In the present embodiment, the conveyance path from the cassette 3 to the registration roller pair 4 is referred to as a first conveyance path.

  The registration roller pair 4 serving as the skew feeding correcting means includes a driving LF roller 4a and a driven pinch roller 4b. The LF roller 4a is driven to convey a required amount of paper by a motor and gear train (not shown). The pinch roller 4b is biased toward the LF roller 4a by a biasing means (not shown). By sandwiching and transporting the sheet S1 to the nip of the registration roller pair 4, the sheet S1 can be transported in the direction of the print head 5 serving as an image forming unit. The registration roller pair 4 during image formation is intermittently conveyed by a predetermined amount by a motor (not shown).

  Further, the registration roller pair 4 is stopped, and the leading edge of the sheet S1 conveyed from the upstream side by the conveyance from the sheet feeding roller 9 is abutted on the nip (contact point between the rollers), so that the leading edge of the sheet is conveyed. A state that is not perpendicular to the direction, that is, skew can be corrected. Here, correcting the skew refers to aligning the leading end substantially perpendicular to the transport direction when the leading end is not perpendicular to the transport direction of the sheet S1. Further, after the skew correction of the sheet S1, the sheet S1 is conveyed with an accurate feed amount by intermittent driving at the time of image formation by the print head 5. Since the amount of feed during the intermittent conveyance of the sheet S1 by the registration roller pair 4 has a great influence on the image quality, the registration roller pair 4 usually has a large conveyance force in the conveyance means of the ink jet printer. High-precision drive control is performed.

  The print head 5 forms an image by ejecting ink droplets from a surface facing the print surface of the paper while reciprocating in the direction perpendicular to the paper conveyance direction, that is, the paper width direction, by a carriage which is a moving means (not shown). Configured. The print head 5 is also configured so that ink of a necessary color and amount is appropriately supplied by an ink supply means (not shown).

  The platen 6 is configured to appropriately maintain the flatness of the printing surface of the paper, the clearance with the print head 5, and the parallelism when an image is printed by the print head 5. The reason why the positional relationship between the print head 5 and the sheet needs to be maintained in this way is to make the landing position accuracy of the ink droplets ejected from the print head 5 high.

  The paper discharge roller pair 7 includes a drive-side paper discharge roller 7a and a driven-side spur 7b, and is configured to nipping and conveying the paper. The paper discharge roller 7a is formed of a high friction member such as rubber, for example, contacts the non-printing surface of the image-formed paper, and transports the paper to the paper discharge tray 8 described later by the action of the spur 7b. Since the spur 7b must be brought into direct contact with the printing surface of the sheet immediately after printing, it is necessary to reduce the contact area as much as possible. Therefore, in this embodiment, the spur 7b has a shape in which a large number of needle-like protrusions are formed on the outer peripheral portion thereof.

  The paper discharge tray 8 is configured so that printed sheets discharged from the paper discharge roller pair 7 can be aligned and stacked in a predetermined amount.

  The paper feed roller 9 constituting the paper feed means is driven by a drive source such as a motor (not shown) and rotates in the direction R shown in the figure to carry the uppermost sheet S1 of the sheet bundle S stacked on the cassette 3. It is conveyed in the direction F to the registration roller pair 4 (that is, in the first conveyance path). The surface of the paper feed roller 9 is composed of a high friction member such as rubber. In the present embodiment, the paper feed roller 9 is rotatably supported by a swing arm 14 that is rotatably supported by a rotation shaft 14a. For this reason, the swing arm 14 rotates around the rotation shaft 14a according to the remaining amount of the sheet bundle S loaded in the cassette 9, and the sheet feeding roller 9 always follows the uppermost sheet S1. ing.

  The separation plate 13 constituting the paper feeding means is configured to separate the paper conveyed in the conveyance direction F by the paper supply roller 9 into only one sheet. This is because not only one sheet but also a plurality of sheets may be fed when the sheet is conveyed by the sheet feeding roller 9. The separation plate 13 is, for example, a PET film, a stainless plate, or the like, and the surface thereof is often configured to be smooth, but the surface may be roughened by sandblasting or the like.

  The inner guide 10 is disposed inside the first transport path as a part of the guide means. In the case of the present embodiment, the sheet S1 is separated and fed into only one sheet by the sheet feeding roller 9 and the separation plate 13, and guide means such as the main body case 2, the inner guide 10, the flapper guide 11, and the upper guide 12 are provided. To reach the registration roller pair 4. The sheet reversing device of the present embodiment is constituted by each element forming the first conveying path described above, whereby the sheet S1 is reversed by approximately 180 °, so-called U-turn conveyance, and skew correction is performed by the registration roller pair 4. After that, it is conveyed to the print head 5 which is an image forming unit. The inner guide 10 cooperates with the main body case 2, the flapper guide 11, the upper guide 12, and the like to form a U-turn conveyance path for the sheet and guide the sheet conveyance.

  A flapper guide 11 serving as a sheet direction changing means is a sheet guide means that is pivotally supported around a rotation shaft 11a disposed inside the main body case 2 outside the first conveyance path, A paper pushing portion 11b extended from 11a in the upstream direction with respect to the paper conveyance direction F of the first conveyance path, and extended from the rotary shaft 11a to the downstream side in the paper conveyance direction of the first conveyance path. The sheet guide portion 11d has a shape. For example, the shape of the paper pushing portion 11b and the shape of the paper guide portion 11d are merged in the vicinity of the rotating shaft 11a to form a substantially “<” shape. The sheet guide 11 is 1) a standby position when the sheet S1 is not in the first conveyance path or before the leading edge of the sheet reaches the registration roller pair 4, and the sheet pushing portion 11b is in the first conveyance path. A first position that does not protrude, and 2) a second position that is pushed by the waist of the sheet S1 after the leading edge of the sheet has hit the registration roller pair 4 and moves in a direction that widens the conveyance path near the loop space A. The rotating shaft 11a is supported so as to be swingable between 1) and 2). In the figure, the position of the two-dot chain line is the first position, and the position of the solid line is the second position.

  When the flapper guide 11 is in the first position, the paper push-in portion 11b is retracted into a part of the main body case 2 and does not protrude into the first conveyance path. Further, when the flapper guide 11 is in the second position, the paper pushing portion 11b protrudes from a part of the main body case 2 to the extent that the first conveyance path is not blocked. The position of the rotary shaft 11a and the shape of the paper pushing portion 11b are such that when the flapper guide 11 rotates and moves from the first position to the second position, the movement locus of the contact portion of the paper pushing portion 11b with the paper S1 is The position and shape include at least a moving component in a direction in which the sheet S1 is pushed in the downstream direction. With this configuration, when the flapper guide 11 is pushed by the waist of the sheet S1 and moves from the first position to the second position, the sheet pushing portion 11b protrudes into the first conveyance path. The sheet S1 is pushed downstream (that is, in the direction of the registration roller pair 4) at the position where it abuts on the sheet S1.

  Here, it is desirable that the contact portion of the paper pushing portion 11b with the paper S1 has a high slidability characteristic. For example, a high sliding material such as polyacetal or polyfluorinated ethylene (trade name: Teflon (registered trademark)) is preferable. Alternatively, as shown in FIG. 3, the contact portion may be a rotating body such as a roller 11e to reduce the sheet conveyance resistance at the time of contact.

  Further, the sheet conveyance surface 11c opposite to the first conveyance path of the paper guide portion 11d is used as the second conveyance path, and the first conveyance from the cassette and the second conveyance path in the vicinity of the front end portion of the paper guide portion 11d. If configured so as to merge with the path, for example, a manual sheet feeding conveyance path or the like may be separately provided as the second conveyance path.

  In addition, the position of the flapper guide 11 is detected by a sensor or the like (not shown) to be used for timing the sheet, or the sheet loop amount is detected in order to appropriately control the conveyance amount when the optimum sheet is pushed. It may be used. By doing in this way, it can also be shared with the paper sensor normally arrange | positioned in a conveyance path.

  The upper guide 12 that constitutes a part of the guide means is disposed above the sheet conveyance path and outside the U-turn portion. The upper guide 12 is configured to receive the sheet S1 conveyed by the sheet feeding roller 9 while being guided by the flapper guide 11 and the inner guide 10, and smoothly guide the leading edge of the sheet to the vicinity of the nip of the registration roller pair 4. ing.

  Next, the operation of the flapper guide 11 when the sheet S1 is fed by the sheet feeding roller 9 and conveyed along the conveyance path will be described. When the flapper guide 11 shown by the two-dot chain line in the figure is in the first position, the paper pushing portion 11b of the flapper guide 11 is in a position where it does not protrude into the conveyance path of the main body case 2. The flapper guide 11 is biased toward the first position by the action of its own weight or by a biasing means (not shown). When there is no sheet S1 or when the leading end of the sheet passes near the flapper guide, the flapper guide 11 starts from the first position. It is configured not to swing. The leading edge of the paper is guided to the inner surface of the paper guide portion 11 d of the flapper guide 11 and delivered to the upper guide 12. As a result, the leading edge of the paper reaches the registration roller pair 4 at the shortest distance that does not form a paper loop. Therefore, productivity in the operation before skew correction is high.

  Thereafter, when the sheet S1 is further conveyed by the sheet feeding roller 9 and the leading end of the sheet abuts against the resist roller pair 4 that is stopped, the sheet S1 in the first conveyance path is bent, and the biasing force of the flapper guide 11 is applied to the sheet S1. The paper guide 11d is pushed against the waist and moved to the second position. When the flapper guide 11 shown by the solid line in the figure is in the second position, that is, when the sheet guide portion 11d of the flapper guide 11 is retracted from the conveyance path, the illustrated loop space A is formed in the first conveyance path. A loop due to the deflection of the sheet S1 is formed in the loop space A. Further, when the paper S1 is conveyed by the paper feeding roller 9 by a predetermined amount after the leading edge of the paper hits the registration roller pair 4, a predetermined paper loop is formed in the loop space A and at the same time, the paper pushing portion 11a of the flapper guide 11 is formed. Protrudes into the first conveyance path and comes into contact with the sheet S1 and acts to push the sheet S1 into the nip of the registration roller pair 4. As a result, a force for pushing the sheet S1 is generated at a position closer to the registration roller pair 4 than the sheet feeding roller 9, and the leading end of the sheet pushed downstream by the sheet feeding roller 9 and the sheet pushing portion 11a is the registration roller pair 4. Therefore, even if the front end of the sheet is skewed, the front end is corrected so as to be substantially perpendicular to the transport direction.

  Normally, the distance from the sheet feeding roller 9 as the conveying means to the downstream conveying means (in this case, the registration roller pair 4) is a distance, and the reversing path is close to 180 ° as in the present embodiment. In the case of (U-turn), the conveyance force of the paper supply roller 9 is not easily transmitted to the vicinity of the front end of the sheet near the nip of the registration roller pair 4, and skew correction may be insufficient. Further, when the paper loop space is on the upstream side to correct the skew of the front end of the paper, the transport force of the upstream transport means (in this case, the paper feed roller 9) is absorbed by the transport path near the loop space. As a result, the skew correction may be insufficient. However, in the present embodiment, the loop space A is arranged closer to the downstream side, that is, near the registration roller pair 4 that is the downstream conveying means, and when the flapper guide 11 is in the second position, the sheet pushing portion. 11b protrudes into the first conveying path so as to push the paper S1 into the nip of the registration roller pair 4, thereby generating a force for pushing the paper S1 at a position closer to the registration roller pair 4 than the paper feed roller 9. Therefore, the conveying force can be effectively applied to the leading edge of the sheet, and the skew feeding correction with the registration roller pair 4 can be performed with high accuracy.

  Thereafter, a drive source such as a motor (not shown) that drives the registration roller pair 4 is activated at a predetermined timing, and is conveyed to the print head 5 to form an image. The sheet S1 on which the image has been formed is discharged to a discharge tray 8 by a pair of discharge rollers 7, and sequentially stacked from the printed sheet S1.

1 is a schematic overall cross-sectional view of an ink jet printer according to an embodiment of the present invention. It is a principal part enlarged view of the inkjet printer in connection with embodiment of this invention. It is other embodiment of the paper pushing-in part 11b of the flap guide 11. FIG. It is a schematic block diagram of the laser printer provided with the conventional paper conveyance apparatus. It is a timing chart explaining the paper conveyance control to the registration roller of the laser printer provided with the conventional paper conveyance apparatus. FIG. 10 is a perspective view illustrating a state where a sheet is conveyed to an intermediate roller 221 in a conventional sheet conveying apparatus. It is a side view which shows the guide plate 230a pivotally supported by the laser printer provided with the conventional paper conveyance apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet printer 2 Main body case 3 Cassette 4 Registration roller pair 5 Print head 6 Platen 7 Paper discharge roller pair 8 Paper discharge tray 9 Paper feed roller 10 Inner guide 11 Flapper guide 11a Rotation shaft of flapper guide 11 11b Paper push-in of flapper guide 11 Part 11c Paper passing surface on the outer side of the flapper guide 11 constituting the second transport path 11d Paper guide part of the flapper guide 11 11e Roll of the paper pushing part 11b 12 Upper guide 13 Separating plate 14 Swing arm 14a Rotating shaft A of the swing arm 14 Loop space S Sheet bundle S1 Uppermost sheet R Rotating direction of paper feed roller 9 F Transport direction of uppermost sheet S1

Claims (3)

Paper feeding means for separating only one sheet from the stacked paper and transporting it in the downstream process;
Guiding means for guiding the paper conveyed from the paper feeding means downstream;
A second position which is arranged in the middle of the guiding means and is a standby position and moved in a direction to widen the conveyance path by being pushed by the waist of the paper while changing the direction of the paper downstream during the conveyance of the paper. A paper direction changing means having a paper pushing shape that is supported so as to be swingable between the first position and the second position, and acts to push the paper to the downstream side on the upstream side of the widened conveying path. ,
A paper reversing apparatus comprising: a skew feeding correcting means for correcting the skew feeding of the paper whose direction has been changed by the paper direction changing means.   2. The sheet reversing device according to claim 1, wherein the sheet pushing shape is a roller rotatably supported by the sheet direction changing means.   An image forming apparatus comprising the sheet reversing device according to claim 1.

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