JP2010095352A - Sheet delivering device, and image forming device equipped therewith - Google Patents

Abstract

An object of the present invention is to provide a sheet conveying apparatus capable of suppressing the occurrence of corner breakage and JAM and an image forming apparatus including the sheet conveying apparatus.
A conveying roller 239 including a pair of rollers is installed so as to face a sheet conveying path 231. In the sheet conveying path 231, a sheet P sent from the conveying roller 239 is guided in a sheet conveying direction more than the conveying roller 239. S is a sheet conveying apparatus having a sheet guide 245 that guides to a downstream conveying path 241 located on the downstream side of S, and the sheet guide 245 moves from the vicinity of one roller 243 constituting the conveying roller 239 to the downstream conveying path 241. And a guide portion 246 that reaches the rotation shaft 243a of the one roller 243 so as to be rotatable around the rotation shaft 243a.
[Selection] Figure 2

Description

  The present invention relates to a sheet conveying apparatus that conveys a sheet by conveying rollers and an image forming apparatus including the sheet conveying apparatus.

  2. Description of the Related Art Conventionally, an electrophotographic image forming apparatus such as an electrophotographic copying machine or a printer includes a fixing device. The fixing device includes a heated fixing roller, and a pressure roller that is pressed against the fixing roller with a predetermined contact pressure, and an unheated developer (for example, on the surface of the fixing roller in the transfer device in the previous stage of the fixing device). , Toner) is transferred between a fixing roller and a pressure roller to heat the unheated developer and fix it on the sheet.

  Further, the image forming apparatus includes a sheet conveying device on the downstream side in the sheet conveying direction of the fixing roller in order to convey the sheet on which the developer is fixed by the fixing device. The sheet conveying apparatus includes a sheet conveying path that conveys a sheet, and a conveying roller that includes a post-fixing roller and a post-fixing driven roller that follows the fixing roller. The sheet is sandwiched between conveyance rollers, and the post-fixing roller rotates as a driving roller, and is conveyed downstream of the sheet conveyance path.

  Specifically, as illustrated in FIG. 5, the conveyance roller 239 is disposed so as to face the sheet conveyance path 231. The driven roller 243 can be brought into and out of contact with the driving roller 242 and is urged to come into contact with the driving roller 242 by an urging member 244 such as a spring. Then, the driven roller 243 moves according to the thickness of the sheet passing through the conveying roller 239.

  A guide portion 248 is formed at the upstream sheet conveyance path end adjacent to the conveyance roller 239 and the downstream sheet conveyance path end so that the sheet conveyance path 231 becomes wider as the conveyance roller 239 is approached. An appropriate gap (t1) is set between the surface of the driven roller 243 and the guide portion 248 (scooping shape) so that the driven roller 243 does not contact the guide portion 248.

  However, since the guide portion 248 and the driven roller 243 are independent of each other, even if the driven roller 243 moves in the contact / separation direction with respect to the driving roller 242, the guide portion 248 does not interlock with the movement. . Accordingly, when the nip between the driven roller 243 and the driving roller 242 and the sheet guide center are offset due to the cause of crossing or attachment of parts, the scooping dimension from the roller nip decreases from X1 to X2, as shown in FIG. This reduces the gap distance. As a result, the distance from the surface of the driven roller 243 to the scooping shape of the guide portion 248 increases from t1 to t2, and a sheet with a curled tip enters the gap, causing a corner break JAM.

In order to solve the above-described problem, for example, as shown in Patent Document 1, the sheet holding direction of the sheet press includes a platen that flatly supports the sheet to be transported and a sheet press that restricts the sheet from being lifted from the platen. There is known a sheet conveying apparatus having a configuration in which a recording sheet guide portion that guides conveyance of a sheet from the upstream side to the sheet press is attached to a pinch roller holder that holds a pinch roller that is a driven roller of the conveying roller. .
JP 2002-249260 A

  However, since the position of the rotation center of the recording sheet guide portion described in Patent Document 1 is provided at a position (pinch roller holder) different from the rotation axis of the pinch roller, the pinch roller of the sheet passing sheet is not There is a problem that the angle of the sheet guide portion changes depending on the movement or attachment accuracy, and causes JAM when the curled sheet is conveyed.

  Accordingly, an object of the present invention is to provide a sheet conveying apparatus capable of suppressing the occurrence of corner breakage and JAM, and an image forming apparatus including the sheet conveying apparatus.

  In order to solve the above problems, in the present invention, a conveyance roller composed of a pair of rollers is installed so as to face the sheet conveyance path, and the sheet fed from the conveyance roller in the sheet conveyance path is transferred to the conveyance roller. A sheet conveying apparatus having a sheet guide for guiding to a downstream conveying path located downstream in the sheet conveying direction, wherein the sheet guide reaches the downstream conveying path from the vicinity of one of the rollers constituting the conveying roller. It has a guide part, is rotatably attached around the rotation axis of the one roller, and is prevented from rotating with respect to the rotation axis.

  The roller to which the sheet guide is attached may be a roller that is provided so as to be able to contact and separate from the other roller among the conveying rollers and is urged toward the other roller by an urging member such as a spring. .

  According to the above configuration, since the sheet guide is attached to the rotation shaft of one of the rollers constituting the conveying roller, the sheet guide follows the behavior of one of the rollers, so that the scooping dimension from the roller nip is immobile, the corner is bent, Occurrence of JAM or the like can be suppressed. Further, since the sheet guide is prevented from rotating with respect to the rotation axis of one of the rollers, the posture of the sheet guide does not change with respect to the sheet conveyed through the sheet conveyance path, and thus there is no possibility of hindering sheet conveyance.

  The sheet guide preferably inserts the downstream end of the guide portion in the sheet conveyance direction into the downstream conveyance path, thereby reliably guiding the sheet to the downstream conveyance path, By engaging the guide portion with the downstream side conveyance path, the attachment angle of the sheet guide can be automatically adjusted in accordance with the behavior of one of the rollers.

  In the sheet conveying apparatus according to the present invention, the conveying roller is composed of a driving roller and a driven roller. As described above, the conveying roller can be brought into contact with and separated from the other roller, and is applied toward the other roller by a biasing member such as a spring. A sheet guide is attached to the roller to be urged. Therefore, the structure of the sheet conveying apparatus can be simplified by making the driven roller freely contactable with respect to the driving roller and attaching the sheet guide to the driven roller.

  Further, if an image forming apparatus such as a copying machine or a multi-function machine provided with the sheet conveying device is used, it is possible to suppress corner folding and paper jamming of the original regardless of the type of the original.

  As described above, according to the present invention, in the conveyance roller, the sheet guide for guiding the sheet from the conveyance roller to the downstream conveyance path is attached rotatably around the rotation axis of the driven roller. Can be suppressed.

  An embodiment according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a configuration example of an image forming apparatus in which a sheet conveying apparatus according to the present invention is used, and FIG. 2 is a partially enlarged cross-sectional view illustrating the sheet conveying apparatus according to the present invention.

  As shown in FIG. 1, the image forming apparatus according to the present embodiment includes a document reading unit 100, an image forming apparatus main body 200, a post-processing device 300, and a sheet stack unit 400. The document reading unit 100 has a document table 101 made of transparent glass or the like on the upper surface. A scanner optical system 111 for optically reading a document (not shown) placed on the document table 101 is disposed on the document table 101.

  The scanner optical system 111 includes an exposure light source 112 for irradiating light on a document (not shown) placed on the document table 101, and a photoelectric conversion element (receiving light reflected by the document). A plurality of reflecting mirrors 113 for guiding the light reflected by the document to the photoelectric conversion element 115, between the exposure light source 112 and the photoelectric conversion element 115, and a CCD (Charge Coupled Device) 115. An imaging lens 114 for imaging the light guided by the reflecting mirror 113 on the photoelectric conversion element 115 is disposed.

  The output signal from the photoelectric conversion element 115, that is, the original image data, is subjected to image processing and then sent to an LSU (laser scanning unit) 201 provided in the image forming apparatus main body 200. Yes.

  The image forming apparatus main body 200 is roughly divided into an image forming unit 210 for forming (printing) an image on a transfer paper P as a sheet, and the transfer paper P. The image forming unit 210 also receives the transfer paper P. And a sheet feeding / conveying section 220 for conveying the sheet. The image forming unit 210 includes the LSU 201 and a photoconductor 211 on which an electrostatic latent image is formed by irradiating the surface with laser light from the LSU 201.

  The photosensitive member 211 has a drum shape that is rotationally driven in the direction of an arrow. The photosensitive member 211 is developed around the photosensitive member 211 from the laser light irradiation point from the LSU 201 toward the rotating direction of the photosensitive member 211. An apparatus 212, a transfer charger 213, a static eliminator 214, and a main charger 215 are arranged.

  The developing device 212 develops the electrostatic latent image on the surface of the photoconductor 211 exposed by the laser beam into a visible image (toner image) with toner, and the transfer charger 213 transfers the toner image on the photoconductor 211. The charge remover 214 removes the charge remaining on the photoreceptor 211 after the transfer of the toner image, and the main charger 215 removes the surface of the photoreceptor 211 from which the residual charge has been removed. Charge to a predetermined potential. Further, although not shown, a cleaning device is provided between the transfer charger 213 and the static eliminator 214 for removing the toner remaining on the photosensitive member 211 after the transfer of the toner image.

  The LSU 201 is not limited to the image data of the document read by the document reading unit 100 described above, but is sent by image information, communication, or the like from an external device such as a computer (not shown) connected to the outside. The photosensitive member 211 is irradiated with a laser based on the information.

  Accordingly, the image forming apparatus includes a copying function for reading an original image by the original reading unit 100 to form an image on a sheet, a FAX function for forming an image on a sheet based on FAX information by communication, and the like from an external device such as a computer. This is a multifunction machine having a print function for forming an image on a sheet based on the image information.

  In the paper feeding / conveying unit 220, a sheet cassette 221 for stocking the transfer paper P and feeding the transfer paper P, and a manual feed tray for feeding the transfer paper P from the side surface of the image forming apparatus main body 200 are provided. 222 is provided.

  At the leading end of the sheet cassette 221 on the transfer paper P feeding side, a feeding roller 223 for feeding the transfer paper P accommodated in the sheet cassette 221 and a transfer paper P accommodated therein (not shown). A roller and a sheet separating portion made of a friction sheet member, a reverse rotation roller, or the like are arranged so that the sheets can be reliably fed out one by one.

  On the downstream side of the transfer roller P in the conveyance direction of the transfer paper P, a feeding pickup roller 224 for guiding the transfer paper P to an image forming position in the image forming unit 210 and a first paper feed path 225 are provided. Yes.

  On the other hand, at the leading end of the manual feed tray 222 on the transfer paper P feeding side, a drawing roller 226 for feeding the transfer paper P on the manual feed tray 222, and image formation in the image forming unit 210 by using the transfer paper P. A pickup roller 227 for feeding out to the position and a second paper feed path 228 are provided.

  Before the image forming position of the image forming unit 210, the transfer paper P fed from the first paper feed path 225 or the second paper feed path 228 is transferred to the toner image on the photoconductor 211 at a predetermined timing. A registration roller 229 is provided for conveyance to a position (image forming position).

  The registration roller 229 has either a first paper feed path 225 or a second paper feed path 228 by a pre-registration detection switch (not shown) provided in the first paper feed path 225 and the second paper feed path 228. Based on a detection signal indicating that the transfer paper P has passed through, the toner image on the photosensitive member 211 and the transfer paper P are driven to be aligned.

  A fixing roller for fixing the toner image transferred onto the transfer paper P by heat on the downstream side of the transfer position where the toner image on the photoconductor 211 is transferred to the transfer paper P in the transport direction. 230 is provided.

  On the downstream side of the fixing roller 230 in the transfer paper P transport direction, a sheet transport path 231 for transporting the fixed transfer paper P and the transfer paper P transported through the sheet transport path 231 are disposed in the image forming apparatus main body 200. A first sheet discharge path 233 is provided for guiding to a discharge roller 232 for discharging to the outside.

  The transfer paper P discharged from the paper discharge roller 232 is discharged to a first paper discharge unit 234 formed below the document reading unit 100. As shown in FIG. 1, the first paper discharge unit 234 is formed on the lower side of the document reading unit 100, on the side surface of the image forming unit 210 of the image forming apparatus main body 200, and on the upper side of the sheet cassette 221. It is formed in the space. Here, the space portion indicates a region below the document reading unit 100 and surrounded by the outer peripheral wall of the image forming apparatus main body 200.

  In order to switch and guide the transfer sheet P to either the first sheet discharge path 233 or the second sheet discharge path 236 leading to the post-processing device 300 on the upstream side of the first sheet discharge path 233 in the conveyance direction of the transfer sheet P. The first switching gate 235 is provided. The first switching gate 235 is provided to be rotatable in the directions of arrows c and d with a branch point of the first sheet discharge path 233 and the second sheet discharge path 236 as a fulcrum.

  That is, when the transfer sheet P is guided to the first sheet discharge path 233, the transfer sheet P is rotated in the direction of the arrow d, the second sheet discharge path 236 is closed, and the transfer sheet P is guided to the second sheet discharge path 236. Rotates in the direction of the arrow c to close the first sheet discharge path 233.

  Further, as shown in FIG. 1, the paper feeding / conveying unit 220 is provided with a reverse conveying path 237 in parallel with the sheet conveying path 231. The reverse conveyance path 237 is a conveyance path used during double-sided printing for forming images on both sides of the transfer paper P. The transfer paper P is conveyed in a direction opposite to the conveyance direction of the sheet conveyance path 231 described above. It is conveyed to the registration roller 229.

  Accordingly, the transfer paper P on which double-sided printing is performed is formed with an image on one side and conveyed to the sheet conveyance path 231, and then guided to the post-processing apparatus 300 by the second sheet discharge path 236 described above, and the post-processing Switched back in the apparatus 300, passes again through the second sheet discharge path 236 and is transported to the reverse transport path 237. The switchback function of the post-processing device 300 will be described later.

  Then, the transfer paper P transported to the reverse transport path 237 is transported to the transfer position of the toner image via the registration roller 229, and the toner image is transferred to the surface where the image is not formed. Then, it is sent out to the sheet conveyance path 231.

  A switching gate 238 is provided at a branch point between the sheet conveyance path 231 and the reverse conveyance path 237 so that the transfer sheet P is blocked when the transfer paper P is conveyed to the reverse conveyance path 237. To prevent the transfer paper P from being conveyed to the sheet conveyance path 231.

  That is, the switching gate 238 is provided so as to be rotatable in the directions of arrows a and b. When the transfer paper P is guided to the sheet conveyance path 231, the switching gate 238 is rotated in the direction of the arrow b to move the reverse conveyance path 237. When the transfer sheet P is closed and guided to the reverse conveyance path 237, the sheet conveyance path 231 is closed by rotating in the direction of arrow a.

  When the transfer paper P is guided to the reverse conveyance path 237, it is necessary to rotate the first switching gate 235 in the arrow c direction so that the second sheet discharge path 236 is opened. As shown in FIG. 1, the post-processing apparatus 300 is configured such that the transfer sheet P conveyed from the second sheet discharge path 236 of the image forming apparatus main body 200 is an escape path 302 or a third sheet that is a second sheet conveyance path described later. A sheet conveyance path 301 for guiding to a staple tray 303 that is a conveyance path, and a discharge roller 318 for discharging the transfer paper P conveyed through the sheet conveyance path 301 to the escape path 302 or the staple tray 303 are provided. Yes.

  The escape path 302 and the staple tray 303 form a relay conveyance path 300a for relaying and conveying the transfer sheet P from the image forming apparatus main body 200 to the sheet stack section 400 serving as a sheet post-processing section.

  The sheet conveyance path 301 forms a sheet conveyance path 300b for conveying a sheet from the image forming apparatus main body 200 to the relay conveyance path 300a. That is, the post-processing apparatus 300 includes the relay conveyance path 300a and the sheet conveyance path 300b.

As shown in FIG. 1, the relay conveyance path 300a is detachably unitized from the sheet conveyance path 300b with the discharge roller 318 at the center. That is, the relay conveyance path 300 a is unitized so as to be detachable from the image forming apparatus main body 200.
Thereby, when the post-processing apparatus 300 is not used, the relay conveyance path 300a can be removed and maintenance can be performed by removing the relay conveyance path 300a, thereby improving the maintainability of the entire apparatus. Can do.

  Further, as shown in FIG. 4, the relay conveyance path 300 a is formed between the document reading unit 100 and the space portion that is the first paper discharge unit 234. When viewed from another angle, it can be said that the relay conveyance path 300a is provided on the surface (rear surface) opposite to the document table 101 of the document reading unit 100. Further, it can be said that the relay conveyance path 300a is formed on the upper surface (ceiling surface) of the space portion which is the first paper discharge portion 234.

  According to the above configuration, the relay conveyance path 300 a that conveys a sheet from the image forming apparatus main body 200 to the post-processing apparatus 300 is between the document reading unit 100 and the space portion surrounded by the outer peripheral wall of the image forming apparatus main body 200. Therefore, the relay conveyance path 300a is formed above the first sheet discharge unit 234 from which the sheet that is not conveyed to the post-processing apparatus 300 is discharged from the image forming apparatus main body 200.

  Accordingly, when a jam occurs in the relay conveyance path 300a, the sheet is not discharged onto the upper surface of the relay conveyance path 330a. Therefore, a sheet that is not conveyed from the image forming apparatus main body 200 to the post-processing apparatus 300 is removed. Even if a sheet remains on the first paper discharge unit 234 to be discharged, jamming can be performed without removing the sheet.

  Therefore, in the relay conveyance path 300a for conveying the sheet formed in the image forming apparatus main body 200 to the post-processing apparatus 300, it is possible to quickly and easily perform jam processing when a problem such as a paper jam occurs. The maintainability can be improved.

  A second switching gate 304 is provided at a branch point between the escape path 302 and the staple tray 303 on the downstream side of the sheet transport path 301 in the transfer sheet P transport direction. The second switching gate 304 is provided so as to be rotatable in the direction of the arrow e · f with the branch point as a fulcrum. When the transfer paper P is guided to the escape path 302, the second switching gate 304 is rotated in the direction of the arrow e, and stapled. When the transfer paper P is guided to the tray 303, it is rotated in the direction of arrow f.

  The escape path 302 is a conveyance path that conveys the transfer paper P that is not subjected to post-processing such as stapling. As shown in FIG. 1, the conveyance portion of the transfer paper P is substantially the same as the original platen 101 of the original reading unit 100. The transfer paper P is formed so as to be parallel to each other and is conveyed in a substantially horizontal state (substantially horizontal state) to a sheet stack unit 400 described later.

  A first paper discharge path 305 and a second paper discharge path 306 are branched on the downstream side of the escape path 302 in the transfer paper P conveyance direction. A third switching gate 307 is provided at a branch point between the first paper discharge path 305 and the second paper discharge path 306, and the transfer paper P transported through the escape path 302 can be discharged as needed. It is switched to either the paper path 305 or the second paper discharge path 306 and conveyed.

  That is, as shown in FIG. 1, the third switching gate 307 is provided so as to be rotatable in the directions of arrows g and h with a branch point between the first paper discharge path 305 and the second paper discharge path 306 as a fulcrum. When the transfer paper P is guided to the first paper discharge path 305, it is rotated in the direction of arrow g. When the transfer paper P is guided to the second paper discharge path 306, it is rotated in the direction of arrow h. It is like that.

  On the other hand, the staple tray 303 is a transport path for transporting the transfer paper P on which post-processing such as stapling is performed, and is substantially parallel to the escape path 302 below the escape path 302 as shown in FIG. As in the escape path 302, the transfer paper P is transported to the sheet stack portion 400 in a substantially horizontal state.

  In the staple tray 303, the transfer paper P is stocked and aligned in a substantially horizontal state, and stapling processing is performed on the transfer paper P aligned in the horizontal state by a staple unit 308 described later. It has become.

  A staple unit 308 that performs stapling processing and a paper discharge roller 309 that discharges the bundle of transfer paper P that has been stapled by the stapling unit 308 are disposed downstream of the staple tray 303 in the conveyance direction of the transfer paper P. Is provided.

  The paper discharge roller 309 is configured to discharge the transfer paper P branched from the escape path 302 by the third switching gate 307 and transported through the second paper discharge path 306. A sheet detection sensor B for detecting the passage of the transfer paper P is provided on the discharge roller 309 before the transfer paper P is obtained.

  The post-processing apparatus 300 having the above-described configuration is provided between the document reading unit 100 and a space formed below the original reading unit 100, so that a space for sheet post-processing is formed on the installation surface of the image forming apparatus. Will be. As a result, the installation area of the image forming apparatus including the post-processing apparatus 300 can be reduced, so that the degree of freedom for installing the image forming apparatus is increased.

  In the post-processing apparatus 300, post-processing such as alignment and stapling of the transfer paper P on which an image is formed is performed in a substantially horizontal state. Therefore, post-processing such as alignment and stapling of the transfer paper P is performed. Can be performed at the same position. This eliminates deformation and alignment disturbance of the transfer sheet P bundle that occurs when the aligned transfer sheet P bundle is conveyed to the stapling position, and ensures that post-processing such as stapling is performed with the transfer sheet P bundle in place. Can do.

  The sheet stack unit 400 stacks the transfer sheets P that have passed through the post-processing apparatus 300. As shown in FIG. 1, the sheet stack unit 400 includes a first sheet stack tray 401 serving as a second sheet discharge unit, and a third sheet discharge. And a second sheet stack tray 402 as a unit.

  On the first sheet stack tray 401, the transfer paper P discharged from the escape path 302 of the post-processing device 300 through the first paper discharge path 305 is stacked. That is, the transfer sheet P that has passed through the post-processing apparatus 300 but has not been subjected to post-processing such as stapling is stacked on the first sheet stack tray 401.

  On the other hand, on the second sheet stack tray 402, the transfer paper P discharged from the paper discharge roller 309 through either the escape path 302 or the staple tray 303 of the post-processing device 300 is stacked. That is, the transfer sheet P that has been subjected to post-processing such as stapling is stacked on the second sheet stack tray 402, but the transfer paper P that has not been subjected to post-processing such as stapling is also stacked. .

  The second sheet stack tray 402 moves up and down according to the load amount of the transfer paper P. That is, when the load amount of the transfer paper P increases, the second sheet stack tray 402 moves downward from a predetermined position. Therefore, when it is necessary to stack a large amount of transfer paper P that has not been subjected to the stapling process, the transfer paper P is discharged from the escape path 302 to the second sheet stack tray 402 via the second paper discharge path 306. become.

  In the image forming apparatus configured as described above, a sheet conveying apparatus that conveys the transfer paper P as a sheet is provided downstream of the fixing roller 230 in the sheet conveying direction S. The sheet conveying apparatus includes a sheet conveying path 231 and a conveying roller 239 installed in the middle of the sheet conveying path 231. The conveyance roller 239 is disposed so as to face the sheet conveyance path 231.

  The sheet conveyance path 231 includes an upstream conveyance path 240 that is located upstream of the conveyance roller 239 in the sheet conveyance direction, and a downstream conveyance path 241 that is located downstream of the conveyance roller 239 in the sheet conveyance direction. The downstream side of the downstream conveyance path 240 is further branched into a first sheet discharge path 233 and a second sheet discharge path 236. The sheet conveyance path 231 is configured by a pair of guide walls that are relatively disposed with a predetermined interval.

  The conveyance roller 239 includes a driving roller 242 as a post-fixing roller and a driven roller 243 driven by the driving roller 242 as shown in FIGS. The driven roller 243 is provided so as to be able to contact and separate from the driving roller 242 and is urged so as to contact the driving roller 242 by an urging member 244 (a spring is used in this embodiment). Then, the driven roller 243 moves in the contact / separation direction according to the thickness of the transfer paper P passing through the transport roller 239.

  A sheet guide 245 that guides the transfer paper P fed from the transport roller 239 to the downstream transport path 241 is attached to the driven roller 243. The sheet guide 245 includes a guide portion 246 that extends from the vicinity of the driven roller 243 to the downstream conveyance path 241, a support portion 247 that supports the guide portion 246, and a bearing portion of the rotating shaft 243 a that is formed on both sides of the support portion 247. 252. The bearing portion 252 is formed in a substantially U shape, and the rotating shaft 243a is rotatably engaged with the concave portion.

  The relationship between the sheet guide 245 and the driven roller 243 will be described in more detail. A rectangular opening 250 is formed in one guide wall 254 of the pair of guide walls, and the driven is driven so as to face the sheet conveyance path 231 from the opening 250. A roller 243 is installed. Side walls 251 that slidably hold the driven roller 243 are formed at both ends of the opening 250 in a direction orthogonal to the sheet conveying direction S. In the opening 250, a guide portion 248 described later is formed at one end edge in the sheet conveying direction S.

  The side wall 251 has a substantially U-shaped notch 253 that opens toward the drive roller 242, and the bearing 252 of the sheet guide 245 is slidably engaged with the notch 253. An urging member 244 is installed at the back of the notch 253 and urges the driven roller 243 toward the driving roller 242 via the bearing 252.

  As described above, since the bearing portion 252 is formed in a substantially U shape, the bearing portion 252 is slidably held in the cut portion 253 without rotating. Further, the sheet guide 245 and the driven roller 242 always slide together in the cut portion 253 by the urging member 244. Further, the rotating shaft 243a is rotatable with respect to the bearing portion. In other words, the sheet guide 245 is rotatably attached to the rotation shaft 243a and is prevented from rotating with respect to the rotation shaft 243a.

  According to the above configuration, the sheet guide 245 can follow the behavior of the driven roller 243, and the gap t3 between the driven roller 243 and the guide portion 246 can be set small as shown in FIG. Become. Therefore, unlike the conventional sheet conveying apparatus shown in FIG. 5, it is not necessary to set a relatively large gap t1 between the driven roller 243 and the upstream end of the downstream conveying path 241, and the driven roller 243 and the guide portion 246 are not required. The occurrence of corner breaks and JAM between the two can be suppressed.

  An end of the guide portion 246 on the downstream side in the sheet conveyance direction is inserted into the downstream conveyance path 241. Thus, by engaging the guide portion 246 with the downstream side conveyance path 241, the attachment angle of the sheet guide 245 can be automatically adjusted according to the behavior of the driven roller 243.

  In addition, the guide portion 246 has a shape that is inclined so as to approach a tangent line in the nip portion of the conveyance roller 239 as it goes downstream in the sheet conveyance direction. As a result, the transfer paper P can be smoothly guided to the downstream conveyance path 241. A guide portion 248 is provided at the upstream end of the downstream side conveyance path 241 such that the guide wall is inclined outward so that the sheet conveyance path 231 becomes wider toward the conveyance roller 239. The guide part 246 and the guide part 248 are formed to have substantially the same inclination angle.

  The sheet guide 245 is set to a length that allows the downstream end of the guide portion 246 to reach the guide portion 248. Further, the inner side of the downstream end of the guide portion 246 is substantially parallel to the sheet conveyance direction. The corner is cut. Accordingly, it is possible to prevent the space in the sheet conveyance path 231 from becoming narrow due to the guide portion 246 being inserted into the downstream conveyance path 241 and hindering the conveyance of the sheet.

  In the present embodiment, a plurality of conveying rollers 239 are arranged in the sheet width direction substantially perpendicular to the sheet conveying direction S. However, the present invention is not limited to this. A conveyance roller may be used.

1 is a block diagram showing an image forming apparatus according to the present invention. The partially expanded sectional view which shows the sheet conveying apparatus which concerns on this invention The partially expanded sectional view which shows the sheet conveying apparatus which concerns on this invention Plan view showing driven roller Partially enlarged cross-sectional view showing a conventional sheath and transfer device 3 is a cross-sectional view showing a state where the sheet guide center is offset in FIG.

Explanation of symbols

90 image reading means 230 fixing roller 231 sheet conveyance path 239 conveyance roller 240 upstream conveyance path 241 downstream conveyance path 242 driving roller 243 driven roller 244 biasing member 245 sheet guide 246 guide section 247 support section 248 guide section 250 opening 251 side wall 252 Bearing part 253 Notch part 254 Guide wall

Claims (5)

A conveyance roller consisting of a pair of rollers is installed so as to face the sheet conveyance path, and the sheet conveyed from the conveyance roller is conveyed downstream from the conveyance roller in the sheet conveyance direction in the sheet conveyance path. A sheet conveying apparatus having a sheet guide for guiding to a path, wherein the sheet guide has a guide portion from the vicinity of one roller constituting the conveying roller to a downstream conveying path, and the rotation shaft of the one roller A sheet conveying device, wherein the sheet conveying device is rotatably mounted around the rotation shaft and is prevented from rotating with respect to the rotation shaft. The sheet conveying apparatus according to claim 1, wherein the one roller is provided so as to be able to contact and separate from the other roller, and is urged toward the other roller by an urging member. 3. The sheet conveying apparatus according to claim 1, wherein an end portion of the guide portion on the downstream side in the sheet conveying direction is inserted into the downstream conveying path. The sheet conveying apparatus according to any one of claims 1 to 3, wherein the conveying roller includes a driving roller and a driven roller, and the sheet guide is attached to the driven roller. An image forming apparatus comprising the sheet conveying device according to claim 1.

Images