JP2009196754A - Conveying device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conveying mechanism capable of skewing paper to be sent to a re-conveyance aligning mechanism in saved space without being affected by paper sizes and the quality of paper. <P>SOLUTION: Individual reversible revolving roll pairs 302 and a clutch 346 aligned in the roll longitudinal direction are used to adjust a difference between revolving periods by adjustments to the open period of the clutch. In such a state that the clutch 346 is disengaged, paper P is not conveyed by the right reversible revolving roll pair 302_R but conveyed only by the left reversible revolving roll pair 302_L. This increases the conveyance amount C_L on the left side by the amount corresponding to clutch disengagement. Skew is intentionally applied to the paper P sent from a reverse-skew roll part 218A toward the re-conveyance aligning mechanism 3 mounted on the downstream side in the conveying direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a transport apparatus and an image forming apparatus having a function of correcting skew of a non-transport object such as paper.

  For example, in an image forming apparatus such as a printing apparatus, a copying apparatus, a FAX apparatus, or a multi-function machine capable of performing a plurality of these functions installed in an office, a mechanism that turns a sheet upside down as an example of a transported body is provided. There is. A typical example is one having a double-sided image forming function.

  For example, when realizing the double-sided image forming function, a structure is adopted in which after an image is formed on one side of a sheet, the paper is drawn to the reverse path side in the middle of the discharge path and turned upside down, and then supplied to the transfer position again. At this time, a mechanism for providing a skew correction function and a side registration correction function for correcting deviations in the paper direction and the width direction has been considered in order to maintain good recording accuracy even during back side printing (see, for example, Patent Documents 1 and 2). reference).

JP 11-349191 A JP 2005-263343 A

  For example, in the mechanism described in Patent Document 1, the re-conveying unit detects a sheet position in the sheet width direction of a sheet using a sheet position detecting device provided upstream of the conveying roller, and based on the detection information. Then, the driven roller driven by the conveying roller is rotated in the direction of correcting the sheet position in the sheet width direction, and the conveying force of the driven roller is applied by changing the traveling direction of the sheet. Is moved in the sheet width direction, so that the sheet position in the sheet width direction of the sheet is corrected during conveyance. In short, a re-conveying sheet is provided by arranging a conveying force applying means having a paper twisting function and a paper twisting space for allowing the paper to enter in a skewed state in front of a portion for performing skew correction and side registration correction of the re-conveying unit. Skew correction and side registration correction.

  Compared to the mechanism described in Patent Document 1, the mechanism described in Patent Document 1 requires a longer transport length for forming the skew, but has a degree of freedom in the shape of the transport path, and the size of the transported object The skew correction of the re-conveyance paper can be performed without being affected by the material.

  On the other hand, in the mechanism described in Patent Document 2, a reversing guide having a continuous cross-sectional shape with different radii on the left and right sides in the sheet width direction is provided in the re-conveying section, and the left and right curvature radii are set differently. The length of the conveyance path from the discharge roller pair to the lateral registration correction roller is made to be different between the left and right in the sheet width direction by smoothly connecting them with a continuous cross-sectional shape in which the radius of curvature gradually changes. In short, the length of the transport path of the re-conveyance section is made to have a difference in length in the paper width direction, and the re-conveyance section enters the portion that performs skew correction and side registration correction in a skewed state.

  Compared with the mechanism described in Patent Document 1, the mechanism described in Patent Document 2 is limited in the shape of the transport path and is affected by the size and material of the transported body, but the skew of re-conveyed paper is reduced in space. Correction can be performed.

  An object of the present invention is to provide a mechanism capable of skewing a transported body in a space-saving manner without being affected by the size and material of the transported body.

  The invention according to claim 1 is provided with a roll mechanism that sandwiches the transported body by a pair of rollers and transports the transported body that is pulled in by rotation driving in a predetermined direction, and the roll mechanism is a predetermined mechanism that transports the transported body. A transport device characterized by gradually varying the transport amount with respect to the transported body in the roll longitudinal direction at the timing.

  According to a second aspect of the present invention, in the first aspect of the present invention, the roll mechanism further comprises a plurality of drive rollers divided in the roll longitudinal direction and a roll material supported on the rotary shaft so as to be freely rotatable. A plurality of driven rollers individually corresponding to each of the plurality of driving rollers, and a driving unit that rotationally drives the plurality of driving rollers. It is characterized by being different.

  According to a third aspect of the present invention, in addition to the second aspect of the invention, the plurality of drive rollers are respectively attached to individual rotation shafts, and the drive unit varies the rotation periods of the plurality of drive rollers. Thus, each conveyance amount is varied in stages.

  According to a fourth aspect of the present invention, in the third aspect of the present invention, the roll mechanism further includes a clutch mechanism that switches the interlocking of the rotations of the plurality of drive rollers, and the drive unit has the clutch mechanism in a connected state. In some cases, the plurality of driving rollers are rotated synchronously, and the clutch mechanism is characterized in that each conveyance amount is changed stepwise by adjusting a period during which the clutch mechanism is in an open state.

  According to a fifth aspect of the present invention, in the second aspect of the present invention, one of the plurality of drive rollers is configured such that the roll material starts to rotate after a predetermined period from the start of rotation of the other roll material. It is configured, and each conveyance amount is varied step by step using a delay period of the rotation start.

  According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the drive roller that causes a delay in the start of rotation includes a push plate attached to the roll material and a longitudinal direction of the rotation shaft inside the roll material. A regulating shaft attached in a direction orthogonal to the elastic shaft, and an elastic member disposed between the regulating shaft and the pressing plate, and the elastic member starts rotating in the direction in which the elastic member compresses. The roll material starts rotating after being compressed to a predetermined amount.

  According to a seventh aspect of the present invention, in the fifth or sixth aspect of the present invention, the plurality of drive rollers are attached to a common rotation shaft and are driven to rotate by a common drive motor. Features.

  The invention according to claim 8 further includes a downstream side transport unit that sandwiches the transported body with a pair of rollers on the downstream side in the transport direction and further transports it downstream, in the invention according to claim 1, The transport unit has an aligning mechanism that corrects the skew of the transported body, and the roll mechanism can switch between forward rotation and reverse rotation. During forward rotation, the transported body is clamped and retracted. In the reverse rotation, the transported body is sent out in the direction opposite to the direction in which the transported body is pulled and pulled, and the transported body is released after a predetermined period.

  The invention according to claim 9 is the invention according to claim 8, wherein the roll mechanism has the same transport amount with respect to the transported body in the longitudinal direction of the roll during normal rotation, and in a predetermined period during reverse rotation. The transport amount with respect to the transported body is gradually changed in the roll longitudinal direction.

  According to a tenth aspect of the present invention, in the invention according to the ninth aspect, the roll mechanism further opens the transported body when the transported body is sandwiched by the downstream transport unit. To do.

  According to an eleventh aspect of the present invention, in the tenth aspect of the present invention, the aligning mechanism further includes a pair of skew rolls in which the rotation shaft is disposed at a predetermined angle with respect to the conveyance direction of the conveyed object. And a side of the transported body abuts against the regulation plate, and the skew and position of the transported body are corrected by pressing the side surface of the transported body against the regulation plate.

  An invention described in claim 12 includes an image forming apparatus comprising: the conveying device according to any one of claims 1 to 11; and an image forming unit that forms an image on a conveyed object. Forming device.

  In the invention described in claim 13, in the invention described in claim 12, the transport device further includes a re-transport path for feeding again the transport target having an image formed on one surface to the image forming unit side, The image forming apparatus is configured to form images on both sides of the transported body.

  According to the first aspect of the present invention, it is possible to realize a transport device that skews the transported body in a space-saving manner without being affected by the size and material of the transported body.

  According to the invention described in claim 2, by using a plurality of individual roll materials arranged side by side in the roll longitudinal direction, compared with the case where the invention according to claim 2 is not adopted, It is possible to realize a transport device that skews the transported body in a space-saving manner.

  According to the third aspect of the present invention, the rotation period of the plurality of drive rollers is made different so that the object to be transported can be easily and space-saving compared with the case where the invention according to the third aspect is not adopted. Can be realized.

  According to the fourth aspect of the present invention, the adjustment of the rotation period difference can be easily realized by adjusting the clutch release period.

  According to the fifth aspect of the present invention, by using the rotation start delay, the conveyance of the conveyed object can be performed in a slanted manner in a small space compared to the case where the invention according to the fifth aspect is not adopted. A device can be realized.

  According to the invention described in claim 6, the device to be conveyed is skewed in a simple and space-saving manner as compared with the case where the invention according to claim 6 is not adopted due to the contrivance from the side of the structure of the roller itself. Can be realized.

  According to the seventh aspect of the present invention, the conveyance device according to the fifth or sixth aspect can be realized with a drive motor smaller than the number of drive rollers.

  According to the eighth aspect of the present invention, the transported body can be supplied to the aligning mechanism by skewing the transported body in a space-saving manner without being affected by the size and material of the transported body.

  According to the ninth aspect of the present invention, the transported body can be drawn without being skewed during the forward rotation operation, and the space saving can be achieved without being affected by the size and material of the transported body during the reverse rotation operation. Thus, the transported body can be skewed and the transported body can be supplied to the aligning mechanism.

  According to the tenth aspect of the present invention, when the skew of the transported body is corrected by the aligning mechanism, the skewed state of the downstream side of the transported body is released, so that the skew can be corrected reliably. .

  According to the eleventh aspect of the present invention, it is possible to realize skew correction and position correction in a direction orthogonal to the transport direction.

  According to the twelfth aspect of the present invention, it is possible to realize an image forming apparatus in which the transported body is inclined in a space-saving manner without being affected by the size and material of the transported body.

  According to the thirteenth aspect of the invention, it is possible to realize an image forming apparatus compatible with double-sided printing in which the transported body is skewed in a space-saving manner without being affected by the size and material of the transported body.

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

<Image Forming Apparatus: First Embodiment>
FIG. 1 and FIG. 1A are diagrams (sectional views) showing an outline of the overall configuration of a first embodiment of an electrophotographic image forming apparatus such as a printing apparatus (printer) or a copying apparatus (copier). Here, FIG. 1 shows an embodiment in which a printing apparatus alone without an image reading apparatus is installed and no manual feeding mechanism is provided. FIG. 1A shows a copying machine in which the image reading apparatus is installed, The form which is a multifunctional machine and is provided with the manual feed mechanism is shown. First, the configuration of FIG. 1 will be described, and then the configuration of FIG. 1A will be described by focusing on the differences from FIG.

  As shown in FIG. 1, an image forming apparatus 1 </ b> A according to the first embodiment (first example) includes a conveyance unit 200 </ b> A according to the first embodiment which is an example of a conveyance apparatus according to the present invention. Note that the image forming apparatus 1 </ b> A is referred to as the image forming apparatus 1 by omitting the English reference A when collectively referred to as those in other embodiments described later. As for other functional elements, English reference symbols A, B, and C are attached when distinguishing the embodiments, and English reference symbols are omitted when collectively described. In addition, when explaining the left and right separately, the reference member “_L” is attached to the member related to the left side, and the reference member “_R” is attached to the member related to the right side. Omit the child.

  The image forming apparatus 1A according to the first embodiment has an image forming unit 100 that transfers a toner image onto a sheet (paper medium) that is an example of a sheet-like transported body and a transfer position that transfers a toner image onto the sheet. 200A of the first embodiment for supplying paper. In addition, the image forming apparatus 1A includes a control unit 400 that controls the entire apparatus, for example.

  An image forming unit 100 provided in the image forming apparatus 1A is a cylindrical (drum) -shaped rotating body that rotates about a rotation axis and a photosensitive drum 101 (an example of an image holding body) that holds an electrostatic latent image. A charging unit 102 that includes a laser light source, a polygon mirror, and a motor (not shown) and charges the photosensitive drum 101 to a uniform potential; and an exposure unit 103 that exposes the charged photosensitive drum 101 according to image information; The housing 104a accommodates a developing roll 104b as an example of a developer holding member, a stirring mechanism (not shown), a layer thickness regulating member, and a developer, and a developer (hereinafter referred to as toner) on the photosensitive drum 101 after exposure. And a transfer unit 105 that transfers toner to the paper P supplied to the transfer position between the developing unit 104 and the photosensitive drum 101.

  Further, the image forming unit 100 includes a neutralizing unit 106 that neutralizes the sheet P and the photosensitive drum 101 after transfer, a cleaning unit 107 that removes dirt such as residual toner from the photosensitive drum 101 after neutralization, and a transfer position. A fixing unit 108 having a heating roll 108a and a pressure roll 108b that are pressed against each other at a fixing position downstream in the conveyance direction of the paper P and that heat and press the paper P passing through the fixing position and fixes a toner image on the paper P. Prepare.

  With this configuration, the image forming apparatus 1A according to the first embodiment forms an electrostatic latent image on the photosensitive drum 101 by the charging unit 102 and the exposure unit 103, and develops the electrostatic latent image by the developing unit 104. A toner image is formed on the photosensitive drum 101, the toner image is transferred to the paper P supplied to the transfer position by the transfer unit 105, the paper P is peeled off from the photosensitive drum 101 by the charge eliminating unit 106, and the toner image is further formed. The transferred paper P is sandwiched and conveyed by the heating roll 108a and the pressure roll 108b to melt and fix the toner image on the paper P, thereby forming an image on the paper P. The cleaning unit 107 cleans the photosensitive drum 101 after transfer.

  In the case of configuring an image forming apparatus for forming a color image, as a configuration of a main part related to image formation, for example, a transfer unit 105 directly transfers a toner image of the photosensitive drum 101 onto a sheet of paper P as a transfer body. For example, a plurality of engines corresponding to output colors of K (black), Y (yellow), M (magenta), and C (cyan) are inlined in the order of K → Y → M → C, for example. The K, Y, M, and C images are processed in parallel (simultaneously) by the four engines, that is, the photosensitive member is placed on the intermediate transfer belt one color at a time according to the arrangement position. A tandem color image forming apparatus configured to transfer a toner image on the drum 101 (especially referred to as primary transfer) and then to transfer a toner image on the intermediate transfer belt onto a sheet (specifically referred to as secondary transfer). Good.

  In such an electrophotographic process, charging of the photosensitive drum 101, exposure of a scanned document image, development, that is, toner application to the photosensitive drum 101, toner transfer to a sheet and toner fixing, and cleaning of the photosensitive drum 101 are performed. It has the process of.

  The conveyance unit 200A provided in the image forming apparatus 1A includes three sheet trays 209 that store a plurality of sheets P, a discharge tray 210 (also referred to as a catch tray) that stores sheets P after image formation, and sheets. Various paper guides 211 that regulate the transport direction of P are provided. In the configuration of the first embodiment, the upper surface of the paper P stored and placed in the paper tray 209 is the printing surface (front surface).

  By various paper guides 211, a paper supply path L1 (specifically, a first supply path L1_1 and a second supply path L1_2) from each paper tray 209 to the transfer position, and a paper discharge path L2 from the fixing position to the discharge tray 210 are provided. In addition, a paper reversing path L3 (specifically, a reversing conveyance path L3_1 and a reconveying path L3_2) is set for drawing the paper P on the discharge path L2 and reversing the front and back and supplying the paper P to the supply path. The reverse path L3 of the transport unit 200A according to the first embodiment is characterized in that the reverse transport path L3_1 is a straight transport path extending linearly from the upper side to the lower side of the image forming apparatus 1.

  The transport unit 200A according to the first embodiment includes a pair of three pickup rolls 212 that carry out the paper P from each paper tray, and a pair of paper P that is carried out from the paper tray 209 to the supply path L1 one by one. A pair of friction rolls 213, a pair of registration rolls 214 for supplying the paper P from the supply path L1 to the transfer position, and a pair of pre-discharge rolls 215 for supplying the paper P after fixing to the carry-out path L2. In the vicinity of the registration roll pair 214, a gate arm 222, a registration sensor 225 for optically detecting the presence or absence of the paper P, and a movable guide 228 are provided.

  Further, the transport unit 200A sends the pair of discharge rolls 216 that discharges the paper P from the carry-out path L2 to the discharge tray 210 and the paper P that passes through the carry-out path L2 as it is to the discharge roll pair 216 side or reverses. A reversing gate 217 that switches whether to draw into the path L3 and a pair of reversing / twisting roll portions 218A that are disposed in the middle of the reversing path L3 and reverse the transport direction of the paper P are provided. The reversing / twisting roll unit 218 (not limited to the reversing / twisting roll unit 218A of the first embodiment) sandwiches the paper P, which is an example of a transported body, by a pair of rollers and rotates the paper P drawn in a predetermined direction. It is an example of the roll mechanism conveyed to.

  The reversing gate 217 has a pull-in roll pair 217_1 that pulls in the paper P and a discharge roll pair 217_2 that sends out the pulled paper P to the discharge roll pair 216 side. The reversing gate 217 is used not only for reversing the paper P during double-sided printing, but also for discharging the paper upside down during single-sided printing.

  The re-conveying path L3_2 is provided on the downstream side in the conveying direction at the time of reverse rotation of the reversing / twisting roll unit 218A, and is an example of a downstream conveying unit that sandwiches the paper P by a roller pair and conveys the paper P further downstream. It is. The sheet P conveyed through the reconveying path L3_2 is also particularly referred to as a reconveying sheet.

  Further, the transport unit 200A includes a plurality of pairs of transport rolls 219 that are disposed on the supply path L1 and transports the paper P, and a plurality of pairs (three in the figure) that transport the paper P disposed on the re-transport path L3_2. Arranged between a skew roll pair 220 (also referred to as an aligner roll pair), a registration roll pair 214, a transport roll pair 219, and a skew roll pair 220, and fed from the transport roll pair 219 and the skew roll pair 220 A pair of pre-registration rolls 221 for supplying the sheet P to the transport roll pair 214 via the second supply path L1_2 is provided.

  In the vicinity of the skew roll pair 220 provided in the re-transport path L3_2 which is an example of the downstream-side transport unit, a regulation plate 370 (also referred to as a side guide) which is an example of a reference guide for side registration correction is provided. The re-feed aligning mechanism 3 that corrects the skew and position of the paper P (particularly, the position in the width direction of the paper P) is configured by combining the pair of skew rolls 220 and the restriction plate 370.

  Roll members other than the reversing / twisting roll unit 218A are pressed against each other in pairs (pairs) in a direction in which the rotation axis is in a direction perpendicular to the transport direction of the paper P, and the press contact portion is a transport path of the paper P. It is arranged so as to be positioned above, and conveys the paper P supplied to the pressure contact position while being rotated in one direction, thereby conveying the paper P to the downstream side of the conveyance path. is there. The reverse / twist roll unit 218A is different from the other rolls only in that it operates so as to reversely rotate after drawing the paper P into the press contact part and send the paper P back in the carrying-in direction.

  Here, the reversing / twisting roll unit 218 (not limited to the reversing / twisting roll unit 218A of the first embodiment) of the present embodiment will be described in detail later, but a predetermined timing for transporting the paper P downstream in the transport direction. In the roll longitudinal direction (the depth direction of the paper surface) of the reversing / twisting roll unit 218, each conveyance amount C with respect to the nip (clamped) sheet P can be adjusted. It is characterized in that it has the same structure in which the transport amounts C are gradually different at different transport timings.

  Here, in order to gradually vary the transport amount with respect to the paper P in the roll longitudinal direction, a plurality of driving rollers including a plurality of driving rollers divided in the roll longitudinal direction and a roll material supported on a rotating shaft so as to be freely rotatable are provided. A plurality of driven rollers that individually correspond to each of the rollers and a drive unit that rotationally drives the plurality of drive rollers are provided in the transport unit 200. Then, at least a plurality of driven rollers are configured to vary the transport amounts of the driven rollers with respect to the transported body in stages in the roll longitudinal direction.

  The simplest configuration is a configuration in which there are two pairs of drive rollers and driven rollers, which are arranged on the left and right in the longitudinal direction of the roll, and the conveyance amount on one side (for example, the right side) (the right conveyance amount C_R) ) And the other side (for example, the left side) the transport amount (left transport amount C_L) can be made the same or different. A difference between the left carry amount C_L and the right carry amount C_R is referred to as a left and right carry amount difference ΔC. In the following (also in the second and third embodiments), in order to facilitate understanding, a description will be given of a configuration in which there are two pairs of driving rollers and driven rollers, but there are three or more pairs of driving rollers and driven rollers. In this case, each conveyance amount of the driven roller with respect to the object to be conveyed may be changed stepwise from one side to the other side.

  By adopting such a structure that can change the conveyance amount C on both sides in the longitudinal direction of the roll and can add a conveyance amount difference (left-right conveyance amount difference ΔC) on both sides, other components are not required. The reversing / twisting roll section 218A itself has a structure in which the sheet P is skewed by adding twist (skew) to the sheet P fed to the skew roll pair 220 side. The reversing / twisting roll unit 218A forms a paper skew before the re-conveying aligning mechanism 3, and more preferably, the reversing / twisting roll unit 218A is reversing and substantially simultaneously with the front end of the paper P being nipped between the first skew roll pair 220_1. By placing the twist roll 218A in a non-nipping state (referred to as nip release), the sheet P is abutted against the re-conveying aligning mechanism 3 with high accuracy, and skew correction and side registration correction are performed.

  In the image forming apparatus 1 </ b> A according to the first embodiment configured as described above, when the image is formed on the front surface, the paper P stored in the paper tray 209 is supplied first by the pickup roll 212 and the friction roll pair 213 one by one. Supplied to the path L1_1, moved in the first supply path L1_1 by the transport roll pair 219, further moved in the second supply path L1_2 by the pre-registration roll pair 221 and supplied to the transfer position by the registration roll pair 214. The toner image is transferred from the photosensitive drum 101, supplied to the carry-out path L <b> 2 by the pre-discharge roll pair 215, and discharged to the discharge tray 210 by the discharge roll pair 216, thereby being conveyed to the discharge tray 210.

  When images are formed on both sides of the sheet P, after the image is formed on one side of the sheet P, the sheet P is placed on the reverse conveyance path L3_1 side by the pulling roll pair 217_1 of the reverse gate 217 in the middle of the discharge path L2. Is then reversed by the reversing / twisting roll unit 218A and the conveying direction of the paper P is reversed and sent to the re-conveying path L3_2 side. The paper P is turned upside down by passing through the re-transport path L3_2 and the second supply path L1_2 in order, and the paper P that is turned upside down is re-transported to the supply path L1 by the transport roll pair 219, and is supplied again to the transfer position. Then, the toner image is transferred from the photosensitive drum 101 at the transfer position, and further discharged onto the discharge tray 210 via the discharge path L2, whereby images are formed on both sides thereof.

  On the other hand, as shown in FIG. 1A, the image forming apparatus 1A of the first embodiment (second example) includes an image reading unit 500 and a manual feeding unit 510 that read a document such as printed paper or a book. In the image forming apparatus 1A of the first embodiment (second example), the configuration of the image forming unit 100 is substantially the same as that of the image forming apparatus 1A of the first embodiment (first example). The arrangement positions of the pick-up roll 212 and the friction roll pair 213 of the two paper trays 209 that store the paper P are changed to the left side. In the configuration of the first embodiment (second example), the lower surface of the paper P stored and placed in the paper tray 209 is the printing surface (front surface). In the reverse path L3 of the transport unit 200A of the first embodiment (first example), the reverse transport path L3_1 is linear from the upper side to the lower side of the image forming apparatus 1, as in the first embodiment (first example). It is a straight conveyance path extending to

<Reversing roll unit: First embodiment>
FIG. 2 shows details of the reversing / twisting roll unit 218A of the transport unit 200A of the first embodiment mounted on the image forming apparatus 1A of the first embodiment and the drive system that drives the reversing / twisting roll unit 218A. FIG. As illustrated, the reversing / twisting roll unit 218A includes reversible driving rollers 310_R and 310_L and reversible driven rollers 320_L and 320_R, which are roll elements divided into left and right in the longitudinal direction of the rotation shaft.

  The left reversible drive roller 310_L is fixed to a left drive rotary shaft 312_L that is a roll shaft (also referred to as a shaft), and the right reversible drive roller 310_R is fixed to a right drive rotary shaft 312_R that is a roll shaft (shaft). A difference from a reversing / twisting roll portion 218B of the second embodiment to be described later is that the left reversible driving roller 310_L and the right reversible driving roller 310_R are fixed to different driving rotation shafts 312_L and 312_R, respectively. .

  Each of the reversible driven rollers 320_L and 320_R is attached to the same driven rotation shaft 322 so as to be rotatable following the rotation of the opposing left reversible drive roller 310_L and right reversible drive roller 310_R. Details thereof will be described later.

  A left idler gear 316_L is attached to one end (left end in the figure) of the left drive rotary shaft 312_L, and a right idler gear 316_R is attached to one end (left end in the figure) of the right drive rotary shaft 312_R. The left idler gear 316_L is fixed to the left drive rotation shaft 312_L, and the left drive transmission gear 330_L fixed to the drive transmission rotation shaft 332 that is a roll shaft is provided so as to mesh with the left idler gear 316_L. Further, a reversible drive motor 334 that rotates the drive transmission rotary shaft 332 forward or reverse is attached to one end (left side in the drawing) of the drive transmission rotary shaft 332. A member 336 is provided on the other (right side in the drawing) of the drive transmission rotating shaft 332 so as to contact the left drive transmission gear 330_L. On the further right side of the member 336, a clutch mechanism 340 for switching the interlocking of the rotations of the left and right reversible driving rollers 310_L and 310_R and the reversible driven rollers 320_L and 320_R is provided.

  The clutch mechanism 340 includes a member 344 attached to the member 336 side of the left clutch rotation shaft 342_L, which is a roll shaft, a left clutch plate 346_L attached to the opposite side of the member 336 side of the left clutch rotation shaft 342_L, A right clutch plate 346_R attached to the left clutch plate 346_L side of the right clutch rotation shaft 342_R, which is a shaft, and a right drive transmission gear 330_R attached to the opposite side of the right clutch plate 346_R of the right clutch rotation shaft 342_R. The right drive transmission gear 330_R meshes with the right idler gear 316_R. The left clutch plate 346_L and the right clutch plate 346_R are collectively referred to as a clutch 346.

  The members 336 and 344 are coupling mechanisms. For example, an electromagnetic clutch mechanism is configured, and a driving voltage is supplied to the electromagnetic clutch mechanism. The electromagnetic clutch mechanism is for switching the presence / absence of contact between the left clutch plate 346_L and the right clutch plate 346_R. This coupling mechanism eliminates the influence on the left reversible rotating roll pair 302_L due to clutch connection switching. In the clutch engaged state, the member 344 moves away from the member 336, but the convex portion of the member 344 is caught by the concave portion of the member 336, so that the left reversible rotating roll pair 302_L and the right reversible rotating roll pair 302_R are driven. In the disengaged state of the clutch, the convex portion of the member 344 is inserted into the concave portion of the member 336, so either of them is a mechanism for driving the left reversible rotating roll pair 302_L.

  Pressure springs 324_L and 324_R are attached in the vicinity of both side portions of the driven rotary shaft 322. The pressure springs 324_L and 324_R are also attached to a support plate (not shown). The pressure springs 324_L and 324_R are pressed in the direction of the left reversible driven roller 320_L facing the left reversible driven roller 320_L, and the right reversible driven roller 320_R is opposed. It is pressed in the direction of the right reversible driven roller 320_R.

  The reverse / twist roll unit 218A further includes a release unit 350 that releases the contact between the left reversible drive roller 310_L and the left reversible driven roller 320_L and the contact between the right reversible drive roller 310_R and the right reversible driven roller 320_R. The release unit 350 includes a release rotation shaft 352 that is a roll shaft, a release arm 354 that is attached to the center of the release rotation shaft 352, and an idler that is attached to one end (left side in the figure) of the release rotation shaft 352. A gear 356 is provided. Further, a release drive transmission gear 360 fixed to a release drive rotary shaft 362 that is a roll shaft is provided so as to mesh with the idler gear 356. Further, a release drive motor 364 that rotationally drives the release drive rotary shaft 362 is attached to one end (left side in the drawing) of the release drive rotary shaft 362.

  As long as there is no release operation by the release unit 350, the pressure pair springs 324_L and 324_R are used for both the left reversible driving roller 310_L and the left reversible driven roller 320_L and the right reversible driving roller 310_R and the right reversible driven roller 320_R. The reversible driven roller 320 is rotated by the rotation of the reversible drive roller 310 during the pressure contact.

  Here, the reverse / twist roll unit 218A of the first embodiment rotates the left reversible driving roller 310_L and the left reversible driven roller 320_L in conjunction with each other by switching the connection / disconnection of the clutch 346, and the right reversible driving roller 310_R. The left and right reversible drive roller 310_L and the left reversible driven roller 320_L rotate in conjunction with each other, but the right reversible drive roller 310_R and the right reversible driven roller 320_R do not rotate. One-side rotation mode can be selected. A difference from a reversing / twisting roll unit 218B of the second embodiment to be described later is that both the reversible drive roller 310 and the reversible driven roller 320 are provided with a conveyance difference mechanism in order to give a difference in the conveyance amount. It is the structure which skews.

<Driving roller: First embodiment>
FIG. 2A is a diagram illustrating details of the reversible driven roller 320A of the first embodiment used in the transport unit 200A of the first embodiment. 2A (1) is a cross-sectional view in the roll longitudinal direction of the reversible driven roller 320A, and FIG. 2A (2) is a cross-sectional view in a direction orthogonal to the roll longitudinal direction of the reversible driven roller 320A. 3) is a cross-sectional view in the roll longitudinal direction of the comparative example, and FIG. 2A (4) is a cross-sectional view in a direction orthogonal to the roll longitudinal direction of the comparative example.

  The left reversible driven roller 320_L and the right reversible driven roller 320_R are provided with a driven rotation shaft 322 so as to pass through the center of the roll material 380, and there is a gap on the outer peripheral side of the driven rotation shaft 322 of the roll material 390. The left reversible driven roller 320_L and the right reversible driven roller 320_R are supported on the driven rotation shaft 322 so as to be freely rotatable.

  For example, the driven rotary shaft 322 is rotatably held by a bearing 380 having a bearing structure including an inner ring 382a, an outer ring 382b, and a plurality of balls 382c disposed between the inner ring 382a and the outer ring 382b. The bearing 382 has an inner ring 382 a fixed to the driven rotating shaft 322 and an outer ring 382 b fixed to the roll material 380. As shown in FIG. 2A (2), stoppers 384 that prevent backlash in the roll longitudinal direction and springs 386 as an example of an elastic member are provided at both ends of the roll material 380 in the roll longitudinal direction. The stopper 384 is fixed to the driven rotation shaft 322, and a spring 386 is disposed between the stopper 384 and the roll material 380. In short, a spring receiving structure is used in the roll longitudinal direction.

  With this structure, the reversible driven roller 320 is attached to the same driven rotary shaft 322 corresponding to each of the left reversible drive roller 310_L and the right reversible drive roller 310_R that can be controlled to have different rotation periods. Unlike the ordinary driven roller, the left reversible driven roller 320_L and the right reversible driven roller 320_R are configured to be independently rotatable.

  That is, in the case of a general driven roller, as shown in FIGS. 2A (3) and 2A (4), the rotating shaft 982 is press-fitted into the roll material 980, and a plurality of roll materials 980 are arranged in the roll longitudinal direction (see FIG. 2), each roll material 980 cannot freely rotate with respect to the bearing 982, and the rotation of each roll material 980_L, 980_R cannot be made independent.

  On the other hand, in the case of the reversible driven roller 320 of the first embodiment, as shown in FIGS. 2A (1) and 2A (2), the roll material 380_L of the left reversible driven roller 320_L and the right reversible driven roller 320_R. The roll members 380_R are all attached to the same driven rotary shaft 322, but are held rotatably with respect to the driven rotary shaft 322 by the bearings 382, so that the rotation of the roll members 380_L and 380_R is independent. Become.

  In the example of the reversible driven roller 320 shown here, the bearings 382 are used to make the rotation of the left and right roll members 380_L and 380_R independent of each other. Other mechanisms such as individual roll shafts and fixing of the respective roll members 380 to the individual roll shafts may be adopted.

<Schematic configuration of control system>
FIG. 3 is a block diagram illustrating an outline of the relationship between the control unit 400 and the image forming unit 100 and the transport unit 200 (not limited to the transport unit 200A). The control unit 400 includes, for example, an image system control unit 410 that mainly controls the operation of the image forming unit 100 that forms a toner image on the photosensitive drum 101 and further transfers and fixes the toner image on the paper P, and the transport unit 200A. And a main control unit 440 for synchronously controlling the two control units 410 and 420 while detecting the conveyance position of the paper P.

  The transport system control unit 420 includes a drive motor 422 that drives the pre-registration roll pair 221 and a drive motor 424 that drives the registration roll pair 214. Further, the transport system control unit 420 determines whether or not the reversible drive motor 334, the release drive motor 364, the left clutch plate 346_L, and the right clutch plate 346_R of the reverse / twist roll unit 218 (not limited to the reverse / twist roll unit 218A) are in contact. To control. In addition, the transfer system control unit 420 also controls operations of, for example, an electromagnetic solenoid 432 that moves the gate arm 222 forward and backward, an electromagnetic solenoid 436 that moves the movable guide 228, and the like.

  When the image forming apparatus 1A is activated, first, a paper carry-out signal is sent from the main control unit 440 to the conveyance system control unit 420, and the conveyance system control unit 420 responds to the hook unit 222a of the gate arm 222 accordingly. The paper P is conveyed until the leading edge of the paper P contacts. Next, at a timing after the detection signal of the sheet P is input from the registration sensor 225 to the main control unit 440, an image formation start signal is sent from the main control unit 440 to the image system control unit 410 and the conveyance system control unit 420. In response to this, the image system control unit 410 forms a toner image on the photosensitive drum 101, while the transport system control unit 420 moves the gate arm 222 backward to transfer the sheet P from the registration roll pair 214 to the transfer position. Then, the toner image is transferred onto the paper P, and the toner image is fixed on the paper P and sent to the discharge path L2.

  In such a series of operations, the conveyance system controller 420 moves the movable guide 228 and controls the rotation of the pre-registration roll pair 221 before the gate arm 222 is retracted after the image formation start signal is input. Or

  Further, the conveyance system control unit 420 controls the timing of the presence or absence of contact of the clutch 346 as a feature of the combination with the reversing / twisting roll unit 218A of the first embodiment, so that the left side of the reversing / twisting roll unit 218A. It also has a function of a conveyance amount control unit that adjusts the conveyance amounts C_L and C_R of the reversible rotating roll pair 302_L and the right reversible rotating roll pair 302_R.

<Conveyance amount adjustment: First embodiment>
4 to 4D are diagrams illustrating a mechanism for adjusting the left conveyance amount C_L and the right conveyance amount C_R in the reversing / twisting roll unit 218A according to the first embodiment. Here, FIG. 4 shows a state where the clutch 346 is connected, and FIG. 4A shows a state where the clutch 346 is disengaged. FIG. 4B is a diagram illustrating the re-conveying aligning mechanism 3 that performs skew correction and side registration correction on the sheet P skewed by the reversing / twisting roll unit 218A. FIG. 4C is a diagram illustrating a state (conveyance path) of conveyance of the paper P in the vicinity of the reversing / twisting roll unit 218A according to the first embodiment. FIG. 4D is a diagram illustrating a state (conveyance path) of conveyance of the paper P in the vicinity of the reverse roll portion of the comparative example.

  The reversing / twisting roll unit 218A of the first embodiment includes a clutch mechanism 340 (specifically, a clutch 346) that is an example of a switching mechanism unit that switches the presence / absence of transmission of the driving force of the reversible driving motor 334 to the right drive transmission gear 330_R. The left and right transport amounts C_L and C_R with respect to the nipped paper P can be adjusted on the left and right in the roll longitudinal direction of the reverse / twist roll unit 218A, and the transport amounts C_L and C_R are the same at a certain transport timing. At different transport timings, the transport amounts C_L and C_R are made different.

  Specifically, as shown in FIG. 4, when the left clutch plate 346_L and the right clutch plate 346_R are in contact with each other and the clutch 346 is connected, the left reversible drive roller 310_L and the left reversible driven roller 320_L The conveyance of the sheet P by the pair of rotating rolls 302_L and the conveyance of the sheet P by the pair of right reversible rotating rolls 302_R by the right reversible driving roller 310_R and the right reversible driven roller 320_R are performed in the same manner. For this reason, the left conveyance amount C_L with respect to the nip (clamped) sheet P of the left reversible rotating roll pair 302_L is the same as the right conveyance amount C_R with respect to the nip (clamped) sheet P of the right reversible rotating roll pair 302_R.

  Here, the timing at which the left and right transport amounts C_L and C_R are made the same while the clutch 346 is connected as shown in FIG. 4 is applied during normal driving, and details are shown in FIG. 4C. As described above, the skew feeding process in the operation of drawing the paper P from the upstream (the first half of the discharge path L2) to the reverse transport path L3_1 by the reversal gate 217 or in the process of sending the paper P to the retransport path L3_2 is completed. Furthermore, it is a time when the paper P is sent out to the re-transport path L3_2 side.

  On the other hand, as shown in FIG. 4A, in a state where the left clutch plate 346_L and the right clutch plate 346_R are released and the clutch 346 is disengaged, the sheet P is not conveyed by the right reversible rotating roll pair 302_R and left Only the conveyance of the paper P by the reversible rotating roll pair 302_L is performed. For this reason, the left conveyance amount C_L is increased by the amount of conveyance of the paper P by the left reversible rotating roll pair 302_L (referred to as “clutch disengagement”) with the clutch disconnected.

  Accordingly, when the paper P drawn to the reverse conveyance path L3_1 side is sent to the reconveyance path L3_2 side, the rotation directions of the left reversible rotary roll pair 302_L and the right reversible rotary roll pair 302_R are reversely rotated. The rotation of the roller 320_R is delayed by the amount of release of the clutch, whereby the sheet P is skewed. The reversing / twisting roll part 218A itself intentionally adds a twist (skew) to the paper P fed to the skew roll pair 220 side. As understood from this explanation, the timing for making the left and right transport amounts C_L and C_R different in the state where the clutch 346 is disengaged as shown in FIG. 4A is applied to the re-transport path L3_2 side. This is when the sheet P is skewed in the process of feeding the sheet P (during the skew forming operation).

  After the sheet P is skewed at a predetermined angle, the left conveyance amount C_L and the right conveyance amount C_R are made equal by connecting the clutch 346. As a result, as shown in FIG. 4B, while the sheet P is kept skewed, the left reversible driven roller 320_L and the right reversible driven roller 320_R move toward the regulation plate 370, which is an example of a side registration correction reference guide. Sent. Then, when the paper P reaches the regulation plate 370, the leading end of the paper P is nipped (nip) between the first skew roll pair 220_1 and at the same time the reversing / twisting roll portion 218A is brought into a non-nip state (nip release). Thus, the sheet P is abutted against the regulating plate 370 with high accuracy, and skew correction and side registration correction are performed.

  In other words, the regulation plate 370 that is an example of a side end position defining member (reference guide) is provided along the conveyance direction on one side of the reconveying path L3_2 that is the reconveying unit of the paper P, and also has a width-shifting function. The row roll pair 220 is arranged in the conveyance path of the sheet P, the sheet P being conveyed is moved toward the restriction plate 370 by the skew roll pair 220, and the side edge (side edge) of the sheet P is moved to the restriction plate 370. By abutting against the wall surface 370a (abutting surface), the skewed state of the skewed paper P is corrected, and at the same time the side registration position is adjusted.

  Three skew roll pairs 220 (in order 220_1, 220_2, and 220_3) are sequentially provided along the transport direction on the downstream side in the transport direction of the reversing / twisting roll unit 218A. Each pair of skew rolls 220 is arranged such that the rotation axis is inclined by a predetermined angle with respect to the transport direction of the paper P. Each skew roll pair 220 is paired with a lower roller (not shown). Further, a pre-registration roll pair 221 (not shown) is provided further downstream than the most downstream skew roll pair 220_3.

  A regulating plate 370, which is an example of a side end position defining member (paper positioning member), is provided on the side portion of the re-conveying path L <b> 3 </ b> _ <b> 2 where the paper P is transported in parallel with the paper P transport direction. Here, the three skew roll pairs 220 have a width-shifting function for moving the sheets P conveyed sequentially from the upstream side toward the regulating plate 370, and the side edges of the sheets P that are shifted by the width-shifting function. Is abutted against the wall surface 370a of the regulating plate 370. The re-feed aligning mechanism 3 that controls the posture of the paper P (skew or the position in the width direction of the paper P) by pressing the side surface of the paper P against the wall surface 370a is configured by the pair of skew rolls 220 and the restriction plate 370. .

  That is, in the transport unit 200A configured as described above, when performing side registration correction and skew correction of the paper P when the paper P is transported on the re-transport path L3_2 side, the left reversible rotating roll pair of the reversing / twisting roll unit 218A 302_L and the right reversible rotating roll pair 302_R are reversely rotated with respect to the drawing time, and the paper P is conveyed to the skew roll pair 220 side while the paper P is sandwiched between the left reversible rotating roll pair 302_L and the right reversible rotating roll pair 302_R. Let

  At this time, the transport system control unit 420 disengages the clutch 346 during a certain period until the leading edge of the paper P reaches the vicinity of the skew roll pair 220_1, and the left transport amount C_L is slightly larger than the right transport amount C_R. By doing so, the paper P sent out to the skew roll pair 220 side is intentionally skewed slightly. Thereafter, both the left reversible rotary roll pair 302_L and the right reversible rotary roll pair 302_R are nip-released until the leading edge of the paper P is nipped by the skew roll pair 220_1. Both the left reversible rotating roll pair 302_L and the right reversible rotating roll pair 302_R are in a state in which the paper P is held until the leading edge of the paper P is held by the skew roll pair 220_1. The sheet P is conveyed while maintaining the posture of the time (the skewed sheet P is maintained in the skewed state). Only the reversing / twisting roll part 218A can realize the twisting function during reversal, and there is no restriction on the transport path length and shape of the reversing path L3. Of course, the sheet is conveyed to the skew roll pair 220 side in a stable sheet skew regardless of the sheet size or the sheet quality.

  When the paper P reaches the skew roll pair 220_1, the paper P is first sandwiched by the skew roll pair 220_1, and the paper P is sandwiched by the skew roll pair 220_2 and the skew roll pair 220_3 in this order. At this time, since each skew roll pair 220 is rotated by driving a skew roller driving motor (not shown), the sheet P is broken from the position indicated by the solid line in the drawing as shown in FIG. It is moved to the position indicated by (dotted line), that is, moved toward the regulating plate 370 side. As a result, the side edge of the paper P is abutted against the wall surface 370a of the regulation plate 370, so that the skew of the paper P generated before that is corrected and the side edge position is also defined at the same time. The skew correction operation and the side registration correction operation are realized simultaneously.

  In other words, the forward / reverse operation of the reversing / twisting roll unit 218A (specifically, the left reversible rotating roll pair 302_L and the right reversible rotating roll pair 302_R) and the nip releasing mechanism are used to give a difference between the left and right roll transport amounts C_L, C_R. When a mechanism is provided and the paper P is transported to the re-transport path L3_2, the paper P is skewed by a certain amount due to the left-right transport amount difference ΔC, and the re-transport aligning mechanism 3 having three pairs of skew rolls 220 receives the paper. By entering P while being skewed and reaching the skew roll pair 220_1 in the reconveying path L3_2, the reconveying aligning mechanism 3 performs skewing correction and side registration correction of the reconveying paper.

  Further, the paper P is conveyed further downstream as the skew roll pair 220 rotates. After this, although not shown, a shift operation is performed so that the paper P moves in the right direction of the drawing by a pair of conveyance rolls (for example, a pre-registration roll pair 221 can be used) driven by a side shift motor. The paper P is translated (side-shifted) in a direction away from the regulation plate 370. When the shift amount reaches a predetermined value, the side-shift operation is terminated, and the paper P is arranged at a desired paper alignment position.

  Between the skew feeding correction operation and the side registration correction operation, both the left reversible rotating roll pair 302_L and the right reversible rotating roll pair 302_R are in the nip release state (unconstrained state). It can move freely in the axial direction of each pair of rolls 302_L, 302_R. In other words, there is no possibility that the roll pairs 302_L and 302_R are inconvenient for the skew correction operation and the side registration correction operation.

  As described above, according to the transport unit 200A including the reversing / twisting roll unit 218A of the first embodiment, the two left-side reversible rotating roll pairs 302_L are transported to the re-transport path L3_2 that is the re-transport unit. , By causing a difference in the respective conveyance amounts C_L and C_R of the right reversible rotating roll pair 302_R, a paper skew is formed in front of the re-conveying aligning mechanism 3, and the front end of the paper is nipped by the skew roll pair 220_1. By releasing, the side registration is corrected by abutting against the re-conveying aligning mechanism 3 with high accuracy. That is, a mechanism is adopted in which the rotation of the right reversible driven roller 320_R of the right reversible rotating roll pair 302_R is delayed by the amount of release of the clutch 346 to skew the paper P. When the paper P is drawn to the reverse conveyance path L3_1, the left side There is no difference between the carry amount C_L and the right carry amount C_R, that is, there is no carry amount difference during forward rotation, but the same amount is carried, but during the reverse operation for reversing the paper P, the left carry amount C_L and the right carry amount C_R. Thus, the left reversible rotating roll pair 302_L and the right reversible rotating roll pair 302_R also serve as twisting rolls during reversal.

  Since the reverse / twist roll 218A (specifically, the left reversible rotary roll pair 302_L and the right reversible rotary roll pair 302_R) also serves as the reverse twist roll, it is different from the reverse / twist roll part 218A as shown in the comparative example of FIG. 4D. The twisting roll 920 and the sheet twisting space 930 and the reversing guide that has a continuous cross-sectional shape with different radii on the left and right in the sheet width direction and a difference in length in the sheet width direction are not required. The skew correction of the re-conveyance paper is realized in the space. In the reversing guide, there is a concern that the skew is not stable depending on the size and quality of the paper (especially whether it is strong or not), but the twisting function by the reversing / twisting roll unit 218A does not have such a problem.

  Further, during the skew correction operation and the side registration correction operation by the skew roll pair 220, both the left reversible rotating roll pair 302_L and the right reversible rotating roll pair 302_R nip release the rear end of the paper P, thereby Since the end is not nip-regulated, a highly accurate side registration correction mechanism is provided. By using the nip releasing function of the reversing / twisting roll part 218A, the reversing / twisting roll part 218A is released from the nip almost at the same time when the leading edge of the paper conveyed to the re-conveying path L3_2 nips the skew feeding roll pair 220. By doing so, skew correction with higher accuracy than that in the case of not adopting the mechanism of the first embodiment is realized. When the leading end of the sheet nips the pair of skew rolls 220_1, the reversing / twisting roll unit 218A releases the nip at the trailing end of the sheet, so the load of the motor that drives the pair of skew rolls 220 is lightened and the skew of the sheet is ensured. It is corrected to. The sheet feeding function of the reversing / twisting roll unit 218A is added with the sheet feeding function in front of the re-conveying aligning mechanism 3, and a plurality of high functions are introduced at low cost and space saving.

  Here, in the case of the reversing / twisting roll portion 218A of the first embodiment, since the clutch mechanism 340 is required, the structure is more complicated and the cost is higher than those of the second and third embodiments. There is an advantage that the adjustment of the difference (as a result, the twist amount with respect to the paper P) can be easily realized by adjusting the release period of the clutch 346.

  In the first embodiment, the clutch mechanism is used as a mechanism for making the rotation periods of the left reversible drive roller 310_L and the right reversible drive roller 310_R attached to the respective left drive rotation shaft 312_L and right drive rotation shaft 312_R different. Although a single reversible drive motor 334 has been used by using it, the mechanism is not limited to the clutch mechanism. For example, the drive rotation shafts 312_L and 312_R may be synchronously rotated by independent reversible drive motors to adjust the rotation period of each drive motor. In this case, a plurality of drive motors and a circuit configuration for synchronously rotating each of them are required, but it may be considered that a clutch mechanism is unnecessary and the mechanical configuration is simplified.

<Image Forming Apparatus: Second Embodiment>
FIG. 5 is a diagram (sectional view) showing an outline of the overall configuration of the image forming apparatus according to the second embodiment. The illustrated image forming apparatus 1B according to the second embodiment includes a conveyance unit 200B according to the second embodiment, which is an example of a conveyance device according to the present invention. In the figure, a modification to the first embodiment (first example) is shown, but the illustration is omitted, but the same modification may be applied to the first embodiment (second example). Good.

  The configuration of the image forming unit 100 is substantially the same as that of the image forming apparatus 1A of the first embodiment. On the other hand, in the conveyance unit 200B provided in the image forming apparatus 1B, the arrangement positions of the pickup roll 212 and the friction roll pair 213 of the three paper trays 209 that store a plurality of paper P are changed to the left side. In the configuration of the second embodiment, the lower surface of the paper P stored and placed in the paper tray 209 is the printing surface (front surface). The reverse path L3 of the transport unit 200B of the second embodiment is a straight transport path in which the reverse transport path L3_1 extends linearly from the upper side to the lower side of the image forming apparatus 1, as in the first embodiment. .

  The transport unit 200B of the second embodiment uses the reversing / twisting roll part 218B of the second embodiment instead of the reversing / twisting roll part 218A. The reversing / twisting roll unit 218B will be described in detail later, but unlike the reversing / twisting roll unit 218A, the variable mechanism for the left and right conveyance amount of the reversing roll is an elastic member between the roll surface and the drive shaft due to the conveyance load of the paper P. This is a structure in which a rotation delay is generated on one of the left and right sides with respect to the shaft by deforming the shaft, thereby providing a left-right conveyance amount difference ΔC.

  In the case of forming images on both sides of the paper P in the transport unit 200B having such a configuration, after an image is formed on one side of the paper P, the paper P is once drawn to the discharge roll pair 216 side, and then the discharge roll pair 216. Are reversed and pulled to the discharge roll pair 217_2 side of the reversing gate 217, and the drawn paper P is sent to the re-transport path L3_2 side through the reversing roll unit 218B. Once the single-side printed paper P is pulled out to the discharge roll pair 216 side, the paper P is turned over by passing through the re-conveying path L3_2 and the second supply path L1_2 in order. By re-conveying to the supply path L1_2 by the registration roll pair 221, the toner image is transferred from the photosensitive drum 101 again at the transfer position, and further discharged to the discharge tray 210 via the discharge path L2. Images are formed on both sides. Incidentally, when discharging the paper P that has been printed on one side with its front and back reversed, after the image is formed on one side of the paper P, the reversing conveyance path L3_1 side is formed by the pulling roll pair 217_1 of the reversing gate 217 in the middle of the discharging path L2. After the paper P is drawn in, the reverse / twist roll unit 218B reverses the transport direction of the paper P, and sends the drawn paper P to the discharge roll pair 216 side.

  Here, the transport unit 200B of the second embodiment basically has a structure for attaching a left-right transport amount difference ΔC to the reversing / twisting roll unit 218B in the same manner as in the first embodiment. Without being necessary, the reversing / twisting roll unit 218B itself twists (skew) the paper P fed to the skew roll pair 220 side to skew the paper P.

  That is, using the forward / reverse operation of the reversing / twisting roll unit 218B (specifically, the left reversible rotating roll pair 302_L and the right reversible rotating roll pair 302_R) and the nip releasing mechanism, the left and right roll transport amounts C_L and C_R are differentiated. When the paper P is transported to the re-transport path L3_2 by a mechanism, the paper P is skewed by a certain amount due to the left-right transport amount difference ΔC, and the re-transport conveyor provided with the triple skew roll pair 220 and the regulating plate 370 is provided. The re-aligning mechanism 3 corrects the skew of the re-conveyed paper and corrects the side registration by causing the paper P to enter the lining mechanism 3 while being skewed and reaching the skew roll pair 220_1 of the re-conveying path L3_2.

<Reversing roll: Second embodiment>
FIG. 6 shows details of the reversing / twisting roll unit 218B of the transport unit 200B of the second embodiment mounted on the image forming apparatus 1B of the second embodiment and the drive system that drives the reversing / twisting roll unit 218B. FIG.

  The reversing / twisting roll portion 218B of the second embodiment is different from the reversing / twisting roll portion 218A of the first embodiment shown in FIG. 2 in that the left reversible driving roller 310B_L and the right reversible driving roller 310B_R are the same. This is characterized in that it is fixed to the drive rotation shaft 312 and does not include the clutch mechanism 340. An idler gear 316 is fixed to the left drive rotary shaft 312_L at one end (left end in the drawing) of the left drive rotary shaft 312_L, and a drive transmission rotary shaft 332 that is a roll shaft so as to mesh with the left idler gear 316_L. A drive transmission gear 330 fixed to the motor is provided. Further, a reversible drive motor 334 that rotates the drive transmission rotary shaft 332 forward or reverse is attached to one end (left side in the drawing) of the drive transmission rotary shaft 332. Both the left reversible driven roller 320_L and the right reversible driven roller 320_R are rotatably attached to the same driven rotation shaft 322 in conjunction with the rotation of the opposing left reversible drive roller 310B_L and right reversible drive roller 310B_R.

  Here, the reversing / twisting roll part 218B of the second embodiment is different from the reversing / twisting roll part 218A of the first embodiment described above in order to give a left-right difference in the conveyance amount. Only the paper feeding mechanism is provided to skew the paper P. In order to adopt such a structure, the reversible drive roller 310B, which will be described in detail later, depends on one of the left reversible drive roller 310B_L and the right reversible drive roller 310B_R (in this example, the right reversible drive roller, depending on the conveyance load of the paper P). 310B_R) and by deforming the elastic member attached between the drive rotary shaft 312 and the inside of the roll rotary shaft 312 in the inside thereof, a rotation delay is generated in the roll material on either the left or right side of the drive rotary shaft 312. In this structure, a left-right conveyance amount difference ΔC is provided.

<Driving roller: Second embodiment>
FIG. 7 is a cross-sectional view showing details of the reversible drive roller 310B of the second embodiment used in the transport unit 200B of the second embodiment. The right reversible drive roller 310B_R has a stopper shaft 391 that is an example of a restriction shaft that is attached to the drive rotation shaft 312 so as to penetrate in the left-right direction perpendicular to the longitudinal direction. The drive rotation shaft 312 and the stopper shaft 391 rotates integrally.

  A left contact pressing plate 392_L and a right contact pressing plate 392_R are arranged on the left and right sides of the stopper shaft 391 protruding from the drive rotating shaft 312 so as to always contact the stopper shaft 391. Further, a left non-contact pressing plate 394_L and a right non-contact pressing plate 394_R are arranged so as not to directly contact the stopper shaft 391. In addition, spring-like springs 396_L and 396_R, which are examples of elastic members, are disposed between the left non-contact pressing plate 394_L and the right non-contact pressing plate 394_R and the stopper shaft 391. In addition, as an elastic member, not only a spring-like spring but a leaf | plate spring, rubber | gum, sponge, etc. can also be used. During the stop, the stopper shaft 391 is in contact with the left contact pressing plate 392_L and the right contact pressing plate 392_R by the biasing force of the springs 396_L and 396_R. The left contact pressing plate 392_L, the right contact pressing plate 392_R, the left non-contact pressing plate 394_L, and the right non-contact pressing plate 394_R are all attached to the roll material 390 of the right reversible driving roller 310B_R so as to rotate integrally. It has become.

  A bearing 398 is provided on the outer peripheral side of the drive rotation shaft 312 of the roll material 390 of the right reversible drive roller 310B_R, and the roll material 390 does not rotate directly and integrally with the rotation of the drive rotation shaft 312. It is like that. As the bearing 398, for example, a bearing structure using a ball 398a may be used. Then, the drive rotating shaft 312 is indirectly rotated by the urging force of the left contact pressing plate 392_L and the right contact pressing plate 392_R and the urging force of the left non-contact pressing plate 394_L and the right non-contact pressing plate 394_R and the springs 396_L and 396_R. The roll material 390 rotates in conjunction with the rotation. In the normal rotation state in which the stopper shaft 391 rotates in the direction of the left contact pressing plate 392_L and the right contact pressing plate 392_R, no rotation delay occurs. On the other hand, in the reverse rotation state where the stopper shaft 391 rotates in the direction of the left non-contact pressing plate 394_L and the right non-contact pressing plate 394_R, the rotation is started by using the compression action and the biasing force of the springs 396_L and 396_R. It is characterized in that a rotation delay period is sometimes formed.

<Conveyance amount adjustment: Second embodiment>
8 to 8B are diagrams illustrating a mechanism for adjusting the left conveyance amount C_L and the right conveyance amount C_R in the reversing / twisting roll unit 218B of the second embodiment. Here, FIG. 8 is a diagram for explaining a mechanism in which the right and left reversible drive roller 310B_R has a left-right conveyance amount difference ΔC. FIG. 8 (1) shows a forward rotation, and FIG. Indicates. FIG. 8A is a diagram illustrating a state in which the paper P is skewed by the reversing / twisting roll unit 218B during the reverse rotation and the side registration correction is further performed. FIG. 8B is a diagram illustrating a state (conveyance path) of conveyance of the sheet P in the vicinity of the reversing / twisting roll unit 218B of the second embodiment.

  The reversing / twisting roll portion 218B of the second embodiment is configured so that the driving rotary shaft 312 has a compression action of a spring 396 that is an example of an elastic member inside one roll of the reversible driving roller 310B (right reversible driving roller 310B_R in this example). By adopting a structure having a conveyance difference mechanism capable of forming a non-rotation period in the right reversible drive roller 310B_R at the start of rotation, the left conveyance amount C_L with respect to the sheet P nipped in the left and right in the roll longitudinal direction of the reverse / twist roll unit 218B The right transport amount C_R can be adjusted, the transport amounts C_L and C_R are the same at a certain transport timing, and the transport amounts C_L and C_R are different at different transport timings.

  Specifically, as shown in FIG. 8 (1), in the forward rotation state, the biasing forces of the left contact pressing plate 392_L and the right contact pressing plate 392_R that are always in contact with the stopper shaft 391 protruding from the driven rotation shaft 322, The right reversible drive roller 310B_R rotates simultaneously with the start of rotation of the drive rotation shaft 312. At this time, the left reversible drive roller 310B_L also rotates simultaneously with the start of rotation of the drive rotation shaft 312. For this reason, the left conveyance amount C_L with respect to the nip (clamped) sheet P of the left reversible rotating roll pair 302_L is the same as the right conveyance amount C_R with respect to the nip (clamped) sheet P of the right reversible rotating roll pair 302_R.

  Here, the timing at which the left and right transport amounts C_L and C_R are the same in the forward rotation state as shown in FIG. 8 (1) is applied in detail, as shown in FIG. 8B (1). When the printed paper P is discharged with its front and back reversed, the paper P drawn into the reversing / twisting roll unit 218B is sent to the discharge roll pair 217_2.

  On the other hand, as shown in FIG. 8 (2) and FIG. 8A, in the reverse rotation state, the left non-contact pressing plate 394_L that is indirectly in contact with the stopper shaft 391 protruding from the drive rotation shaft 312 via springs 396_L and 396_R. The right side non-contact pressing plate 394_R does not rotate until the springs 396_L and 396_R are fully contracted until the springs 396_L and 396_R are fully contracted by the urging force of the drive non-contact pressing plate 394_R. The reversible drive roller 310B_R rotates. At this time, the left reversible drive roller 310B_L rotates simultaneously with the start of rotation of the drive rotation shaft 312. There are springs 396_L and 396_R between the stopper shaft 391 and the left non-contact pressing plate 394_L and the right non-contact pressing plate 394_R, and the rotation start of the right reversible driving roller 310B_R is slightly delayed with respect to the left reversible driving roller 310B_L. The left transport amount C_L is increased by a slight delay in the start of rotation of the right reversible drive roller 310B_R.

  After the drive rotation shaft 312 starts rotating in the direction in which the springs 396_L and 396_R compress, after the springs 396_L and 396_R are compressed to a predetermined amount (specifically, after the springs 396_L and 396_R are fully contracted) Since the driving roller 310B_R also starts to rotate, the left carry amount C_L and the right carry amount C_R become the same during the subsequent period, whereby the sheet P is skewed as shown in FIG. While maintaining the state, the left reversible drive roller 310B_L and the right reversible drive roller 310B_R are sent to the regulation plate 370 side, which is an example of a reference guide for side registration correction, which is the same as in the first embodiment.

  In the transport unit 200B of the second embodiment, when the paper P drawn to the reverse transport path L3_1 side is sent to the retransport path L3_2 side, the rotation directions of the left reversible rotary roll pair 302_L and the right reversible rotary roll pair 302_R are reversed. However, at this time, the rotation of the right-side reversible drive roller 310B_R is delayed, so that the paper P is skewed. Similar to the reversing / twisting roll portion 218A of the first embodiment, the reversing / twisting roll portion 218B itself intentionally twists the paper P fed to the skew roll pair 220 side. As understood from this description, the timing at which the left and right transport amounts C_L and C_R are different in the reverse rotation operation state as shown in FIG. 8B is applied as shown in FIG. 8B (2). As described above, the single-side printed paper P is once drawn to the discharge roll pair 216 side, and then the discharge roll pair 216 is reversed to be drawn to the discharge roll pair 217_2 side of the reversing gate 217, and the drawn paper P is reversed roll section 218B. This is a time when the sheet P is skewed in the process of being sent to the re-transport path L3_2 through (at the time of skew forming operation).

  As described above, the transport unit 200B including the reversing / twisting roll unit 218B according to the second embodiment also moves toward the re-transport path L3_2 that is the re-transport unit, similarly to the transport unit 200A according to the first embodiment. At the time of conveyance, a sheet skew is formed in front of the re-conveying aligning mechanism 3 by making a difference between the conveyance amounts C_L and C_R of the two left reversible rotating roll pairs 302_L and the right reversible rotating roll pair 302_R. When the leading edge of the sheet is nipped at 220_1, the nip release is performed at the same time, so that the side registration is corrected by abutting against the re-transport aligning mechanism 3. The reversing / twisting roll unit 218B (the left reversible rotating roll pair 302_L and the right reversible rotating roll pair 302_R) also serves as the reversing twisting roll, and the same functions and functions as in the first embodiment are obtained.

  Here, in the case of the reversing / twisting roll portion 218B (also the reversing / twisting roll portion 218C described later) of the second embodiment, the rotation period difference is from the start of rotation of the drive rotation shaft 312 (that is, the stopper shaft 391) to the spring 396_L, This is the time until 396_R is fully contracted and is structurally determined. Therefore, it is difficult to adjust the difference in the rotation period (resulting in the amount of twist with respect to the paper P). However, it is possible to realize a reverse twist function by providing a rotation period difference on the left and right of the reverse / twist roll part 218B only by the structure of the right reversible drive roller 310B_R, and the advantage that the clutch mechanism 340 as in the first embodiment is not required. There is.

<Image Forming Apparatus: Third Embodiment>
FIG. 9 is a diagram (sectional view) illustrating an overview of the overall configuration of the image forming apparatus according to the third embodiment. An image forming apparatus 1 </ b> C according to the third embodiment shown in the figure includes a conveyance unit 200 </ b> C according to the third embodiment, which is an example of a conveyance apparatus according to the present invention. In the figure, a modification to the first embodiment (first example) is shown, but the illustration is omitted, but the same modification may be applied to the first embodiment (second example). Good.

  The configuration of the image forming unit 100 is substantially the same as that of the image forming apparatus 1A of the first embodiment. On the other hand, in the conveyance unit 200C provided in the image forming apparatus 1C, the arrangement positions of the pickup roll 212 and the friction roll pair 213 of the three paper trays 209 that store a plurality of paper P are changed to the left side. In the configuration of the third embodiment, the lower surface of the paper P stored and placed in the paper tray 209 is the printing surface (front surface). Unlike the first and second embodiments, the reverse path L3 of the transport unit 200C of the third embodiment is that the reverse transport path L3_1 is a transport path disposed below the re-transport path L3_2. There are features.

  The conveying unit 200C of the third embodiment uses the reversing / twisting roll part 218C of the third embodiment instead of the reversing / twisting roll part 218A. The reverse / twist roll part 218B has the same structure as the reverse / twist roll part 218B of the second embodiment described above. That is, unlike the reversing / twisting roll portion 218A, the variable mechanism for the left and right conveyance amount of the reversing roll is different from the reversing / twisting roll portion 218A, and the elastic member between the roll surface and the drive shaft is deformed by the conveyance load of the paper P. In this structure, a rotation delay is generated in order to provide a left-right conveyance amount difference ΔC.

  In the case of forming images on both sides of the paper P in the transport unit 200C having such a configuration, after the images are formed on one side of the paper P, the pair of pulling rolls 217_1 of the reversing gate 217 are in the middle of the discharge path L2. After pulling the paper P to the reverse conveyance path L3_1 side, the reverse / twist roll unit 218C reverses the conveyance direction of the paper P, and sends the drawn paper P to the re-conveyance path L3_2 side. The paper P is turned upside down by passing through the re-transport path L3_2 and the second supply path L1_2 in order, and the paper P that is turned upside down is re-transported to the supply path L1 by the transport roll pair 219, and is supplied again to the transfer position. Then, the toner image is transferred from the photosensitive drum 101 at the transfer position, and further discharged onto the discharge tray 210 via the discharge path L2, whereby images are formed on both sides thereof.

<Conveyance amount adjustment: Third embodiment>
FIG. 10 is a diagram illustrating a mechanism for adjusting the left conveyance amount C_L and the right conveyance amount C_R in the reversing / twisting roll unit 218C of the third embodiment. Specifically, FIG. 10 shows a state (conveyance path) of conveyance of the paper P in the vicinity of the reversing / twisting roll unit 218B of the third embodiment.

  The reverse / twist roll part 218C of the third embodiment has the same structure as the reverse / twist roll part 218B of the second embodiment, and includes a stopper shaft 391, a left non-contact pressing plate 394_L, and a right non-contact pressing plate 394_R. There are springs 396_L and 396_R between the left reversible drive roller 310B_L and the left carry amount C_L is increased by a little behind the start of rotation of the right reversible drive roller 310B_R.

  The difference from the transport unit 200B of the second embodiment is that the reverse transport path L3_1 is not a straight transport path extending linearly from the upper side to the lower side of the image forming apparatus 1, but the reverse transport path L3_1 is a re-transport path. Although the conveyance path is arranged below L3_2, there is no significant difference in other points.

  In the transport unit 200 of the third embodiment, when the paper P drawn to the reverse transport path L3_1 side is sent to the retransport path L3_2 side, the rotation directions of the left reversible rotary roll pair 302_L and the right reversible rotary roll pair 302_R are reversely rotated. However, at this time, the rotation of the right reversible drive roller 310B_R is delayed, and the paper P is skewed. Similar to the reversing / twisting roll part 218A of the first embodiment, the reversing / twisting roll part 218C itself intentionally adds twist to the sheet P fed to the skew roll pair 220 side. As can be understood from this description, the timing for making the left and right transport amounts C_L and C_R different in the reverse rotation operation state as shown in FIG. 8B is applied to the sheet on the re-transport path L3_2 side. This is when the sheet P is skewed in the process of feeding P (at the time of skew forming operation).

  As described above, the transport unit of the first embodiment is also provided by the transport unit 200C including the reverse / twist roll unit 218C of the third embodiment (effectively the same as the reverse / twist roll unit 218B of the second embodiment). As in the case of 200A, when transporting to the re-transport path L3_2 side which is the re-transport section, the transport amounts C_L and C_R of the two left reversible rotating roll pairs 302_L and the right reversible rotating roll pair 302_R are set differently. A paper skew is formed in front of the transport aligning mechanism 3, and the front end of the paper is nipped by the skew roll pair 220_1 and simultaneously nip-released, so that the side registration correction is made with high accuracy by abutting against the re-transport aligning mechanism 3. The reversing / twisting roll unit 218B (the left reversible rotating roll pair 302_L and the right reversible rotating roll pair 302_R) also serves as the reversing twisting roll, and the same functions and functions as in the first embodiment are obtained.

  Further, as can be understood from the difference in configuration between the second embodiment and the third embodiment, any of the reversing / twisting roll portions 218B, 218C can realize a reversing twist function, There are no restrictions on the shape. Of course, the sheet is conveyed to the skew roll pair 220 side in a stable sheet skew regardless of the sheet size or the sheet quality.

  By the way, in the reversible drive roller 310B employed in the second and third embodiments, when the reverse rotation is started, the rotation of one of the reversible drive rollers 310B (the right reversible drive roller 310B_R in the previous example) is delayed so that the paper P Therefore, not only the skew function during double-sided printing, but also the skew function functions when discharging the reverse side (reverse) during single-sided printing.

  For example, in the case of the conveyance path of the second embodiment, as shown in FIG. 8B (2), when the paper P printed on one side is reversed and discharged, the paper P sent from the pulling roll pair 217_1 is discharged. At the time of pulling in the reversing / twisting roll unit 218B, the conveyance direction is the same as that when reversing the paper P for backside printing. Therefore, when the paper P is drawn and sent to the reverse conveyance path L3_1, the paper P is skewed. Will be.

  Further, in the case of the transport path of the third embodiment, as shown in FIG. 10, when the paper P printed on one side is reversed and discharged, the paper P drawn into the reversing / twisting roll unit 218C is discharged. When the paper P is sent to the 217_2 side, the transport direction is the same as when the paper P is reversed for backside printing. Therefore, when the drawn paper P is sent to the discharge roll pair 217_2 side, the paper P is skewed. become.

  Therefore, when the reverse printing mechanism for reverse side printing is adopted by the reversible drive roller 310B employed in the second and third embodiments, it means that the paper P is skewed (paper is skewed) and discharged. . However, normally, it may be considered that even if the paper P is discharged at an angle in this way, it does not cause a big problem.

  Incidentally, when the paper skew at the time of discharge is not preferable as the discharge quality, for example, the following measures may be taken. For example, by introducing the mechanism of the reversible drive roller 310B of FIG. 7 also to the reverse roll portion 218C and the discharge roll pair 217_2 on the opposite side in the longitudinal direction, the oblique directions are opposite to each other, so that the skew at the time of discharge Correct. At that time, it is preferable that the reverse roll portion 218C is nip-released at the sheet nip timing by the discharge roll pair 217_2 so that the rear end of the sheet is in a free state.

1 is a diagram illustrating an outline of an overall configuration of an image forming apparatus according to a first embodiment (first example). 1 is a diagram illustrating an outline of an overall configuration of an image forming apparatus according to a first embodiment (second example). It is a figure which shows the detail of the drive system which drives the reverse roll part of 1st Embodiment, and the said reverse roll part. It is a figure explaining the detail of the reversible driven roller of 1st Embodiment currently used for the conveyance part of 1st Embodiment. 2 is a block diagram illustrating an outline of a relationship between a control unit, an image forming unit, and a conveyance unit. It is a figure (clutch connection state) explaining the mechanism which adjusts the conveyance amount of the right and left in the reverse roll part of 1st Embodiment. It is a figure (clutch release state) explaining the mechanism which adjusts the conveyance amount of the right and left in the reverse roll part of 1st Embodiment. It is a figure explaining the re-conveying aligning mechanism 3 which performs skew feeding correction and side registration correction. It is a figure explaining the conveyance path of the reverse roll part vicinity of 1st Embodiment. It is a figure explaining the conveyance path near the inversion roll part of a comparative example. It is a figure which shows the outline | summary of the whole structure of the image forming apparatus of 2nd Embodiment. It is a figure which shows the detail of the drive system which drives the reverse roll part of 2nd Embodiment, and the said reverse roll part. It is sectional drawing which shows the detail of the reversible driven roller of 2nd Embodiment. It is a figure explaining the mechanism which gives the conveyance amount difference between right and left with the reverse roll part of 2nd Embodiment. FIG. 6 is a diagram illustrating a state in which a sheet is skewed by a reversing roll during reverse rotation and further side registration correction is performed. It is a figure explaining the conveyance path of the reverse roll part vicinity of 2nd Embodiment. It is a figure which shows the outline | summary of the whole structure of the image forming apparatus of 3rd Embodiment. It is a figure explaining the conveyance path (conveyance path) of the reverse roll part vicinity of 3rd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 100 ... Image forming part, 101 ... Photosensitive drum, 102 ... Charging part, 103 ... Exposure part, 104 ... Development part, 105 ... Transfer part, 106 ... Static elimination part, 107 ... Cleaning part, 108 ... Fixing section, 200 ... conveying section (conveying device), 209 ... paper tray, 210 ... discharge tray, 211 ... paper guide, 214 ... registration roll pair, 215 ... pre-discharge roll pair, 216 ... discharge roll pair, 217 ... reversing gate, 218... Reversing / twisting roll section, 219... Transporting roller pair, 220... Skew feeding roller pair, 3 .. re-transporting aligning mechanism, 302 .. reversible rotating roll pair, 310. Reversible drive motor, 340 ... clutch mechanism, 346 ... clutch, 346 ... left clutch plate, 350 ... release part, 354 ... release arm, 364 ... ,... Regulating plate (reference guide for side registration correction), 370a... Wall surface, 390... Roll material, 391 .. stopper shaft (regulating shaft), 392. ... spring (elastic member), 398 ... bearing, 400 ... control unit, 410 ... image system control unit, 420 ... transport system control unit, 436 ... electromagnetic solenoid, 440 ... main control unit, L1 ... supply path, L2 ... discharge path , L3 ... reverse path, L3_1 ... reverse transport path, L3_2 ... re-transport path, P ... paper

Claims (13)

A roll mechanism is provided that conveys the object to be conveyed, which is sandwiched by a pair of rollers and pulled in by rotation, in a predetermined direction,
The said roll mechanism gradually changes the conveyance amount with respect to the said to-be-conveyed body in the roll longitudinal direction at the predetermined timing which conveys the said to-be-conveyed body. The conveying apparatus characterized by the above-mentioned. The roll mechanism includes a plurality of driving rollers divided in a roll longitudinal direction, and a plurality of driven rollers each having a roll material supported on a rotating shaft so as to be freely rotatable and corresponding to each of the plurality of driving rollers. A drive unit that rotationally drives the plurality of drive rollers;
The transport apparatus according to claim 1, wherein in the roll longitudinal direction, each transport amount with respect to the transport target by each roller is changed stepwise. Each of the plurality of drive rollers is attached to a separate rotating shaft,
The transport device according to claim 2, wherein the drive unit varies the transport amounts stepwise by changing the rotation periods of the plurality of drive rollers. The roll mechanism has a clutch mechanism that switches the rotation of the plurality of drive rollers.
The drive unit is configured to synchronously rotate the plurality of drive rollers when the clutch mechanism is in a connected state.
The conveying device according to claim 3, wherein the clutch mechanism adjusts a period during which the clutch mechanism is in an open state to vary the respective conveying amounts stepwise. One of the plurality of drive rollers is configured such that the roll material starts to rotate after a predetermined period from the start of rotation of the other roll material,
The transport apparatus according to claim 2, wherein each of the transport amounts is changed stepwise using a delay period of rotation start. The driving roller that causes a delay in the start of rotation includes a pressing plate attached to the roll material, a restriction shaft attached in a direction perpendicular to the longitudinal direction of the rotation shaft, and the restriction shaft inside the roll material. An elastic member disposed between the pressing plate and the rotation of the roll member after the elastic member compresses to a predetermined amount after the rotation shaft starts rotating in a direction in which the elastic member compresses; The conveyance device according to claim 5, wherein the conveyance device starts. The conveying device according to claim 5 or 6, wherein the plurality of driving rollers are attached to a common rotating shaft and are rotationally driven by a common driving motor. On the downstream side in the transport direction, a downstream transport unit that sandwiches the transported body by a pair of rollers and transports further to the downstream side,
The downstream transport unit has an aligning mechanism that corrects skew of the transported body,
The roll mechanism is capable of switching between forward rotation and reverse rotation,
During forward rotation, the transported body is sandwiched and pulled,
At the time of reverse rotation, the transported body is sent out in a direction opposite to the direction in which the transported body is sandwiched and the transported body is pulled in, and the gripping of the transported body is released after a predetermined period of time. The transport apparatus according to claim 1. The roll mechanism is
At the time of forward rotation, in the roll longitudinal direction, the transport amount to the transported body is the same,
The transport apparatus according to claim 8, wherein a transport amount with respect to the transported body is gradually changed in a roll longitudinal direction during a predetermined period during reverse rotation. The transport apparatus according to claim 9, wherein the roll mechanism opens the transported body when the transported body is sandwiched by the downstream transport unit. The aligning mechanism includes a pair of skew rolls arranged so that a rotation axis is inclined at a predetermined angle with respect to a transport direction of the transported body, and a regulating plate on which a side of the transported body abuts. The conveyance device according to claim 10, wherein the skew and the position of the conveyed object are corrected by pressing a side surface of the conveyed object against a regulation plate. An image forming apparatus comprising: the transport device according to claim 1; and an image forming unit that forms an image on the transported body. The transport device has a re-transport path that sends the transport target on which an image is formed on one side to the image forming unit side again,
The image forming apparatus according to claim 12, wherein the image forming apparatus is configured to form images on both surfaces of the transported body.

Images