JP2007131403A - Sheet aligning device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a sheet aligning device capable of securely correcting bending of a sheet to the carrying direction. <P>SOLUTION: In a central part in the width direction of an inner face 90A of a guide member 90, a pressing guide part 92 protruded to the inner face 90A is provided. Paper P fed from a paper sheet carrying path 28 in the upstream side to the paper sheet aligning device 80 is sandwiched by rotating carrying rolls 84 and is carried to the downstream side. The tip of the paper P abuts on resist rolls 86 in the stopped state and a loop L is formed. By the pressing guide part 92 of the guide member 90, pressing force is applied to a central part of the loop L in the width direction from the back face side. Due to this, pressing force generated in the large loop side becomes small and pressing force in the small loop side becomes large. As a result, the tip in the small loop side appropriately abuts on the resist rolls 86. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet aligning device and an image forming apparatus, and more specifically, a sheet applied to a sheet aligning device or the like that forms a loop on a sheet-like recording medium such as a sheet and corrects the bending of the sheet with respect to the conveyance direction. The present invention relates to an alignment apparatus and an image forming apparatus that forms an image on a sheet-like recording medium in which the bending in the conveyance direction is corrected by the sheet alignment apparatus.

  In a loop aligning type paper aligning device that is mounted on an image forming apparatus and that forms a loop by abutting the front end of a paper against a resist roll to correct the bending of the paper, when there is one guide member that presses the back surface of the loop, As shown in FIGS. 9A and 9B, a large pressing force is generated on the large loop side (LL) of the sheet P (FL), and the leading end of the sheet P is the nip portion N of the pair of registration rolls 200. Or the end of the roll, and the side where the loop is small (LS) has a small pressing force (FS), so the pressing toward the nip N of the resist roll 200 becomes weak, There is a problem that bending correction is not performed properly.

In order to solve this problem, a guide member that presses the back surface of the loop is configured to be swingable in the paper width direction, and the back surface on the small side of the loop can also be pressed (for example, see Patent Document 1), or A technique has been proposed in which a plurality of swingable guide members are provided in the sheet width direction so that a pressing force is generated on the small loop side (see, for example, Patent Document 2).
JP-A-7-267427 JP-A-8-113389

  However, in the configuration of the above-mentioned Patent Document 1, only a uniform pressing force is generated in the paper width direction, and the small side of the loop cannot be strongly pressed. Further, since the guide member contacts the entire surface in the width direction of the paper, the small loop end cannot be properly abutted against the registration roll due to the frictional resistance generated between the paper and the guide member. Further, in the case of Patent Document 2, since a pressing force is generated also on the large loop side, similarly to Patent Document 1, the leading edge of the paper cannot be properly abutted. For this reason, in these configurations, there is a problem that it is not possible to reliably correct the bending of the sheet with respect to the conveyance direction.

  In view of the above-described facts, an object of the present invention is to provide a sheet aligning device and an image forming apparatus that can reliably correct the bending in the sheet conveyance direction.

  In order to achieve the above object, the invention according to claim 1 includes a pair of auxiliary rolls arranged on the upstream side of the conveyance path in which the sheet is conveyed and a pair of correction rolls arranged on the downstream side, A sheet conveyed on the basis of a substantially central reference in the width direction is sandwiched by the pair of rotated auxiliary rolls and conveyed downstream, and a sheet loop is formed by abutting the leading end of the sheet against the stopped pair of correction rolls. Thus, in the sheet aligning device that corrects the bending of the sheet with respect to the sheet conveyance direction, the sheet is guided in the sheet width direction from the back side of the sheet loop while guiding the sheet between the pair of auxiliary rolls and the pair of correction rolls. A guide means for applying the highest pressing force to the central portion is provided.

  In the present invention, for example, by guiding both ends in the sheet width direction, the sheet that is conveyed with the substantially central reference in the conveyance path width direction, that is, with the approximate center in the sheet width direction aligned with the approximate center, The rotation of the pair of auxiliary rolls arranged on the upstream side of the conveyance path causes the sheet leading edge to strike a pair of stopped correction rolls held between the auxiliary rolls and conveyed downstream, and arranged on the downstream side of the conveyance path. It is applied to form a sheet loop. The highest pressing force is applied to the sheet loop from the back side to the central portion in the sheet width direction by the guide means provided between the auxiliary roll and the correction roll. For example, in the case of a structure that contacts both side portions in addition to the central portion in the sheet width direction, any guide member that presses the central portion with a larger force than the both side portions is included in this guide means.

  In this way, the highest pressing force is applied from the back side to the center of the seat loop, so that the pressing force generated on the large loop side is reduced, and the pressing force generated on the small loop side is increased, resulting in a small loop. The tip on the side is properly brought into contact with the correction roll. Thereby, the bending of the sheet with respect to the conveyance direction is reliably corrected.

  According to a second aspect of the present invention, in the sheet aligning apparatus according to the first aspect, the guide means contacts the sheet only at a central portion in the sheet width direction.

  In the present invention, the frictional resistance between the sheet and the guide means is reduced on both sides in the sheet width direction, so that the tip on the small loop side can be more reliably abutted against the correction roll. Bending correction accuracy is increased.

  According to a third aspect of the present invention, in the sheet aligning apparatus according to the first or second aspect, the guide means is a rotation that is pivotally supported in the sheet pressing direction by being pivotally supported on the upstream side in the sheet conveying direction. It has a moving guide member and urging means for urging the rotation guide member in the pressing direction.

  In the present invention, for example, in the case of a fixed guide member, the center portion of the back surface is strongly pressed against the guide member in the process of increasing the seat loop, so that a high pressing force is generated and the bending is corrected. In the case of a rotating guide member urged to the front, the central portion of the back surface is pushed by the rotating guide member even before the seat loop becomes large, and a pressing force is generated, and the pressing force is increased as the loop becomes larger. The tip of the small loop side can be more reliably abutted against the correction roll, and the sheet bending correction accuracy can be improved. Further, when the rotation guide member is brought into contact with the sheet only at the center in the sheet width direction, the sheet bending correction accuracy can be further improved.

  In addition, for example, when the rotation guide member is provided on a curved conveyance path, the sheet conveyed to the correction roll side by the auxiliary roll is smoother along the curved shape of the conveyance path than the fixed guide member. Since the sheet can be guided while being bent, the sheet guide performance is improved.

  According to a fourth aspect of the present invention, in the sheet aligning apparatus according to the first or second aspect, the guide means is an elastic guide that is supported on the upstream side in the sheet conveying direction and is elastically deformable in the sheet pressing direction. It has the member.

  In the case of the present invention as well, as in the configuration of the third aspect, the central portion of the back surface is pushed by the elastic guide member before the seat loop becomes large, generating a pressing force, and the pressing force is increased as the loop becomes larger. Therefore, the tip of the small loop side can be further abutted against the correction roll, and the sheet bending correction accuracy can be improved. Further, when this elastic guide member is also brought into contact with the sheet only at the central portion in the sheet width direction, the sheet bending correction accuracy can be further improved.

  Similarly, when this elastic guide member is provided on the curved conveyance path, the sheet to be conveyed can be guided while being smoothly curved along the curved shape of the conveyance path, thereby improving the guideability of the sheet. be able to. Further, such an elastic guide member can simplify the configuration.

  According to a fifth aspect of the present invention, there is provided an image forming apparatus comprising the sheet aligning device according to any one of the first to fourth aspects, wherein the sheet aligning device corrects the bending with respect to the conveying direction by the sheet aligning device. An image forming unit forms an image on a recording medium.

  If the image forming apparatus includes the sheet aligning apparatus, an image can be formed on a sheet-like recording medium in which the bending in the conveyance direction is reliably corrected, so that the inclination and displacement of the image with respect to the recording medium are suppressed. And good image formation can be realized.

  According to the sheet aligning device and the image forming apparatus of the present invention, it is possible to reliably correct the bending with respect to the sheet conveyance direction.

  Hereinafter, a sheet feeding device to which a sheet feeding apparatus according to an embodiment of the present disclosure is applied and an image forming apparatus equipped with the sheet feeding device will be described with reference to the drawings.

  An image forming apparatus 10 according to this embodiment shown in FIG. 1 is a copying machine using an electrophotographic system. As shown in the drawing, a document placed on a document tray is imaged on the upper surface of an image forming apparatus main body 12. An automatic document feeder 14 is provided that automatically feeds the document to the reading position and automatically ejects it after reading the image.

  Inside the image forming apparatus main body 12, a document reading unit 16 that reads an image of a document sent from the automatic document feeder 14 and converts it into an image signal, and an image (paper) based on the image signal from the document reading unit 16. An image forming unit 18 that forms a toner image), a paper feeding device 20 that supplies paper to the image forming unit 18, and a paper aligning device 80 that corrects bending in the transport direction of the paper supplied to the image forming unit 18 Is provided.

  As shown in FIG. 2, the paper feeder 20 has two small paper cassettes 22A, 22B, A3 size and other large size papers PL in which small size paper PS such as A4 size and letter size frequently used is stored. Large paper cassettes 24A and 24B, and paper feeding mechanisms 26A, 26B, 26C, and 26D that feed out paper P (PS, PL) from these paper cassettes 22A, 22B, 24A, and 24B. A paper transport path 28 for guiding the paper P to the image forming section 18 and a plurality of transport roll pairs 30 for transporting the paper to the image forming section 18 side along the paper transport path 28 are provided.

  The small paper cassettes 22A and 22B have the same configuration and common components, and have the same paper feed capacity and accommodate a large amount (for example, 1500 sheets) of small-size paper PS stacked. Is done. In addition, each of the paper cassettes 22A on the upstream side (the right side in FIG. 2) is located on the downstream side (the left side in FIG. 2). ) Are slightly above the paper feed cassette 22B and are arranged in steps.

  Inside the paper feed cassettes 22 </ b> A and 22 </ b> B, there is provided a tray 32 that can be moved up and down by an elevating mechanism (not shown) using a motor as a drive source, and small-size paper PS is stacked on the tray 32. Are accommodated in the paper feed cassettes 22A and 22B.

  The large paper feed cassettes 24A and 24B are arranged in a substantially two-tiered manner above the paper feed cassettes 22A and 22B arranged in parallel, and are accommodated in a state where large-size papers PL are stacked.

  The paper feed mechanisms 26 (26A to 26D) provided corresponding to the paper feed cassettes 22A, 22B, 24A, and 24B have the same configuration and share components. The paper feed mechanism 26 includes a pickup roll 34 for feeding the uppermost paper P in the paper feed cassette in the paper feed direction, a feed roll 36 and a retard roll 38 for feeding the fed paper P one by one, Is provided with a support mechanism that rotatably supports each of these rolls, a motor as a drive source for rotationally driving each roll, and a rotational force transmission mechanism that transmits the rotational force of the motor to each roll. These parts are housed in a frame 40.

  Further, for the paper feed mechanism 26A corresponding to the upstream paper feed cassette 22A, the lower frame 40A constituting the lower surface portion of the frame 40 is a small size paper PS stacked on the tray 32 of the downstream paper feed cassette 22B. It is arranged close to the upper end with respect to the rear end portion.

  Above the sheet feeding device 20, a sheet aligning device 80 is connected to the downstream end (upper end portion) of the sheet conveying path 28, and the sheet aligning apparatus 80 includes a sheet P (PS) from the sheet conveying path 28. , PL) is sent.

  The sheet aligning device 80 includes a sheet conveying path 82 that connects between the sheet conveying path 28 on the paper feeding apparatus 20 side and the image forming unit 18, and a pair of conveying rolls (auxiliary rolls) that are disposed on the upstream side of the sheet conveying path 82. ) 84 and a pair of resist rolls (correction rolls) 86 disposed on the downstream side, although not shown, a support mechanism that rotatably supports each of these rolls, a motor as a drive source that rotationally drives each roll, and A rotational force transmission mechanism that transmits the rotational force of the motor to each roll is provided, and the paper P is transported to the downstream side by the rotation of the transport roll 84, and a loop is formed by abutting the front end of the paper against the stopped resist roll 86. Thus, the bending of the paper P with respect to the transport direction is corrected (loop aligning). Then, the registration roll 86 and the transport roll 84 are rotated at a predetermined timing (image formation timing) after the bending correction, and the paper P is fed into the image forming unit 18.

  Further, the paper transport system of the image forming apparatus 10 transports the paper P with a substantially central reference in the width direction of the paper transport paths 28 and 82, that is, in a state where the approximate center in the paper width direction is aligned with the approximate center. It is a center cash register method for transporting.

  The image forming apparatus 10 has the above-described configuration. In the image forming apparatus 10, an image of a document sent from the automatic document feeder 14 is converted into a read image signal by the document reading unit 16, and the image signal is converted into the image signal. Based on this, the image forming unit 18 feeds the paper feed cassettes 22A, 22B, 24A, and 24B by the paper feed mechanisms 26A, 26B, 26C, and 26D, transports the paper transport path 28 by the transport roll pair 30, and the paper aligning device 80. An image of the original is copied onto the paper P by forming an image on the supplied paper P with the bending in the conveyance direction corrected.

(First embodiment)
Next, the sheet aligning device 80 according to the first embodiment of the present invention will be described in detail.

  As described above, the sheet aligning device 80 includes the pair of transport rolls 84 disposed on the upstream side (the sheet feeding device 20 side) in the sheet transport direction and the pair of sheets disposed on the downstream side (the image forming unit 18 side). A sheet conveyance path 82 is provided between the registration roll 86. As shown in FIG. 3A, the paper transport path 82 is hung from the upstream side to the downstream side so that the paper P sent from the lower side on the upstream side is sent to the right side on the downstream side, and is directed upward from the upper side to the right side. The auxiliary guide member 88 is disposed inside the bending portion and the guide member 90 is disposed outside.

  On the inner surface 90A of the guide member 90, a pressing guide portion 92 that protrudes with respect to the inner surface 90A is provided. As shown in FIG. 3B, the pressing guide portion 92 has a rectangular shape when the inner surface 90A of the guide member 90 is viewed from the front, and is arranged at the center portion in the width direction (paper direction: W) of the guide member 90. Has been.

  The image forming apparatus 10 of the present embodiment is compatible with image formation (copying) of A3 size (297 mm × 420 mm) to B6 size (128 mm × 182 mm), whereas the guide member 90 has a width dimension. : WA is set to be larger than the maximum paper width dimension (297 mm), for example, 300 mm, and the width dimension of the pressure guide portion 92: WB is about 40% to 80% of the minimum paper width dimension (128 mm), for example, 50 to 100 mm Is set.

  The sheet aligning device 80 of the present embodiment is configured as described above. In the sheet aligning device 80, the sheet P fed from the sheet transport path 28 at a substantially central reference (center register) in the transport path width direction is rotated. The paper roll is nipped by the carrying roll 84 and conveyed downstream, and the leading edge of the sheet is abutted against the outer peripheral surface or the nip portion N of the resist roll 86 in a stopped state to form a loop L (see FIG. 3A). A pressing force is applied to the loop L from the back side to the central portion in the paper width direction by the pressing guide portion 92 of the guide member 90 provided between the transport roll 84 and the registration roll 86. As a result, as shown in FIGS. 4A and 4B, the pressing force generated on the large loop side becomes small, the pressing force generated on the small loop side becomes large, and the tip on the small loop side becomes the registration roll. As a result, the paper P is properly abutted against the outer peripheral surface 86 or the nip portion N, and the bending of the paper P with respect to the transport direction is reliably corrected.

  Further, here, since the pressing guide portion 92 contacts the paper P (loop L) only at the center in the paper width direction, the frictional resistance between the paper P sheet and the guide member 90 is small at both sides in the paper width direction. As a result, the tip of the small loop side can be further abutted against the registration roll 86, and the accuracy of correcting the bending of the paper P can be improved.

  Therefore, in the image forming apparatus 10 including the sheet aligning device 80, an image is formed on the sheet P in which the bending with respect to the transport direction is reliably corrected, thereby suppressing the inclination and displacement of the image with respect to the sheet P. Excellent image formation can be realized.

(Second Embodiment)
Next, a guide member according to a second embodiment of the present invention will be described.

  The second embodiment is a modification regarding the shape of the pressing guide portion in the guide member described in the first embodiment.

  In the example shown in FIG. 5A, the pressing guide portion 94 is divided into two in the width direction (arrow W direction) of the guide member 90, and a concave portion 96 whose bottom surface is flush with the inner surface 90A is provided therebetween. It has been.

  Further, in the example shown in FIG. 5B, the pressing guide portions 98 are arranged at substantially equal intervals along the width direction (arrow W direction) of the guide member 90, and extend along the paper conveyance direction. It is comprised by the rib-shaped protrusion.

  As described above, the pressing guide portion is not limited to the continuous integrated shape as in the first embodiment, but is divided in the width direction of the guide member 90 as shown in FIGS. 5 (A) and 5 (B). It is also possible to form the divided guide guides 94, 98, etc., and the press guides 94, 98 also apply a pressing force to the central portion of the back surface of the loop L, and the sheet P of the paper P in the transport direction. The bend can be corrected reliably.

(Third embodiment)
Next, a paper aligning device according to a third embodiment of the present invention will be described.

  As shown in FIGS. 6A to 6C, in the sheet aligning device 100 of the present embodiment, the sheet pressing direction is provided at a substantially intermediate portion in the sheet conveying direction of the outer guide member 102 constituting the sheet conveying path 82. A rotation guide member 104 that rotates is provided.

  As shown in FIG. 6D, the rotation guide member 104 is provided with a pair of bearing portions 106 on both sides on the upstream end side (the lower end side in FIG. 6D), and this pair of bearing portions. By inserting the support shafts 108 into the shaft holes formed in 106, the upstream side is pivotally supported and can be rotated in the paper pressing direction. In addition, a tension coil spring 110 is installed between a connection portion (not shown) to the apparatus frame provided outside the auxiliary guide member 88 and the bearing portion 106, and the spring force of the tension coil spring 110 is used. The rotation guide member 104 is urged in the paper pressing direction.

  Similar to the guide member 90 of the first embodiment, a pressing guide portion 112 protruding from the inner surface 104A is provided on the inner surface 104A of the rotation guide member 104. As shown in FIG. 6D, the pressing guide portion 112 is also rectangular when the inner surface 104A of the rotation guide member 104 is viewed from the front, and the width direction of the rotation guide member 104 (paper direction: W). It is arranged in the central part.

  As described above, in the sheet aligning device 100 of the present embodiment, before the loop L is formed on the sheet P in the state in the middle of the sheet conveyance shown in FIG. 6A, or immediately after the leading edge of the sheet shown in FIG. Even before the loop L of the paper P becomes large in this state, the central portion of the back surface of the loop L is pressed by the pressing guide portion 112 of the rotation guide member 104 biased in the paper pressing direction, and a pressing force is generated. As the loop L increases, the pressing force is increased. Therefore, the tip on the small loop side can be more reliably abutted against the registration roll 86, and the accuracy of correcting the bending of the paper P can be improved.

  Also in the case of the rotation guide member 104, since the pressing guide portion 112 is brought into contact with the paper P (loop L) only at the central portion in the paper width direction, the accuracy of bending correction of the paper P is further improved.

  Further, when the rotation guide member 104 is provided in the curved sheet conveyance path 82 as in the present embodiment, the conveyance roll 84 is used as compared with the fixed pressing guide portion 92 as in the first embodiment. Since the paper P conveyed to the registration roll 86 side can be guided while being smoothly curved along the curved shape of the paper conveyance path 82 (see FIG. 6A), buckling that is likely to occur particularly in thin paper is prevented. As a result, the guideability of the paper P is improved.

(Fourth embodiment)
Next, a sheet aligning device according to a fourth embodiment of the present invention will be described.

  As shown in FIGS. 7A and 7B, in the sheet aligning device 120 of the present embodiment, the guide member 122 is a substantially intermediate portion in the sheet conveying direction of the outer guide member 122 constituting the sheet conveying path 82 and the guide. A rectangular opening 124 is formed at the center of the member 122 in the width direction (paper direction: W), and a rotation pressing member 126 that rotates in the paper pressing direction is provided in the opening 124. ing.

  As shown in FIG. 7D, the rotation pressing member 126 has a rectangular shape that is slightly smaller than the opening 124 when the inner surface 122A of the guide member 122 is viewed from the front. A pressing guide portion 128 is provided so that the entire inner surface protrudes in the sheet pressing direction. Further, the upstream end portion (the lower end portion in FIGS. 7A and 7B) is pivotally supported so as to be rotatable in the sheet pressing direction, and is connected to the apparatus frame provided outside the guide member 122. Is biased in the paper pressing direction by the spring force of the compression coil spring 130 installed between the portion (not shown) and the outer surface of the rotation pressing member 126.

  As described above, also in the sheet aligning device 120 according to the present embodiment, before the loop is formed in the middle of the sheet conveyance or immediately after the leading edge of the sheet is increased, the rotation pressing member 126 pressed in the sheet pressing direction is pressed. The guide portion 128 pushes the center of the back surface of the loop to generate a pressing force, and the pressing force is increased as the loop becomes larger. Therefore, the tip of the small loop side reliably comes into contact with the registration roll 86, and the accuracy of correcting the skew of the paper is improved.

  Similarly to the third embodiment, the effect of improving the paper bending correction accuracy by bringing the pressing guide portion 128 into contact with the paper (loop) only at the central portion in the paper width direction, and the curved paper conveyance path 82. Thus, the effect of improving the paper guide property can be obtained.

(Fifth embodiment)
Next, a paper aligning device according to a fifth embodiment of the present invention will be described.

  As shown in FIGS. 8A to 8C, in the sheet aligning apparatus 140 of the present embodiment, the inner side 142A side of the outer guide member 142 constituting the sheet conveying path 82 is shown in FIG. 8D. As shown in the drawing, a rectangular elastic guide member 144 made of a metallic leaf spring such as SUS is disposed at the center of the guide member 142 in the width direction (paper direction: W).

  The elastic guide member 144 is cantilevered with its upstream end (the lower end in FIGS. 8A to 8D) fixed to the upstream end of the guide member 142, and in an unloaded state, the auxiliary guide The member 88 is approached (see FIG. 8A).

  As described above, also in the case of the sheet aligning device 140 of this embodiment, as in the third and fourth embodiments, before the loop formation in the middle of the sheet conveyance shown in FIG. 8A, or as shown in FIG. 8B. Since the loop L immediately after the leading edge of the paper is increased, the central portion of the back surface of the paper P is pressed against the elastic guide member 144 to generate a pressing force, and the pressing force is increased as the loop L increases. The tip of the small loop side can be reliably abutted against the registration roll 86, and the accuracy of bending correction of the paper P can be increased. Further, when this elastic guide member is also brought into contact with the sheet only at the central portion in the sheet width direction, the sheet bending correction accuracy can be further improved.

  Also in the present embodiment, the effect of improving the paper bending correction accuracy by bringing the elastic guide member 144 into contact with the paper P (loop L) only at the center in the paper width direction, and the curved paper conveyance path 82. Thus, the effect of improving the paper guide property can be obtained. Further, such an elastic guide member 144 can simplify the configuration.

  The present invention has been described in detail with reference to the first to fifth embodiments. However, the present invention is not limited to these embodiments, and various other modes can be implemented within the scope of the present invention. is there.

  For example, in the first to fifth embodiments described above, only the center portion in the paper width direction is brought into contact with the loop L of the paper P from the back side, but the first and second embodiments are used. In the case of the guide member 90 of the third embodiment, the rotation guide member 104 of the third embodiment, etc., the inner surface portions occupying both sides of the pressing guide portions 92, 94, 98, 112 are directed from the pressing guide portion side toward both end portions. A configuration may be adopted in which the taper surface is formed at a low level and the taper surface contacts the paper P. Even in that case, since the highest pressing force is applied to the center of the back surface of the loop by the pressing guide portion, it is possible to reliably correct the bending of the sheet with respect to the transport direction.

  Further, the present invention is not limited to the above-described copying machine, but can be applied to other image forming apparatuses such as a laser printer and an ink jet printer, and a sheet aligning apparatus on which these printers are mounted. Furthermore, the present invention is not limited to the above-described sheet aligning device that corrects the bending of the sheet-like recording medium in the conveyance direction, and is a sheet that corrects the bending of the sheet in the conveyance direction in order to process a sheet such as a polymer film. It can also be applied to a matching device.

1 is a configuration diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a configuration diagram illustrating a schematic configuration of a paper feeding device and a paper aligning device installed in the image forming apparatus of FIG. 1. (A) is a longitudinal cross-sectional view showing the sheet aligning apparatus according to the first embodiment of the present invention, and (B) is a view of a guide member provided in the sheet aligning apparatus of (A) as viewed from the inner surface side. FIG. 5A is a perspective view and FIG. 5B is a plan view illustrating a state in which the sheet bending with respect to the conveyance direction is appropriately corrected by the sheet aligning device according to the first embodiment of the present invention. (A), (B) is the figure which looked at the guide member which concerns on the 2nd Embodiment of this invention from the inner surface side. (A)-(C) are the longitudinal cross-sections which show the structure of a paper alignment apparatus and paper conveyance and a loop formation process which concern on the 3rd Embodiment of this invention, (D) is paper alignment of (A)-(C). It is the figure which looked at the guide member provided in the apparatus from the inner surface side. (A) is a longitudinal section showing a sheet aligning device according to a fourth embodiment of the present invention, and (B) is a view of a guide member provided in the sheet aligning device of (A) as viewed from the inner surface side. (A)-(C) are the longitudinal cross-sections which show the structure of a paper alignment apparatus and paper conveyance and a loop formation process which concern on the 5th Embodiment of this invention, (D) is paper alignment of (A)-(C). It is the figure which looked at the guide member provided in the apparatus from the inner surface side. FIG. 7A is a perspective view and FIG. 5B is a plan view showing a state where the sheet bending with respect to the conveyance direction is not properly corrected by the conventional configuration.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 18 Image forming part 80 Paper alignment apparatus (sheet alignment apparatus)
82 Paper transport path (transport path)
84 Transport roll (auxiliary roll)
86 Registration Roll (Correction Roll)
88 Auxiliary guide member 90 Guide member (guide means)
92 Pressing guide (guide means)
94 Pressing guide (guide means)
98 Pressing guide (guide means)
100 Paper alignment device (sheet alignment device)
104 Rotating guide member (guide means / rotating guide member)
110 Tensile coil spring (biasing means)
120 Paper alignment device (sheet alignment device)
122 Guide member (guide means)
126 Rotating pressing member (guide means / rotating guide member)
128 Pressing guide (guide means / rotating guide member)
130 Compression coil spring (biasing means)
140 Paper alignment device (sheet alignment device)
142 Guide member (guide means)
144 Elastic guide member (guide means / elastic guide member)
L loop P paper (sheet / recording medium)
PS paper (sheet / recording medium)
PL paper (sheet / recording medium)

Claims (5)

A pair of auxiliary rolls arranged on the upstream side of the conveyance path in which the sheet is conveyed and a pair of correction rolls arranged on the downstream side are rotated, and the sheet conveyed on the substantially central reference in the conveyance path width direction is rotated. Sheet alignment that corrects the bending of the sheet with respect to the sheet conveyance direction by forming a sheet loop by abutting the leading end of the sheet against the pair of correction rolls held between the pair of auxiliary rolls and conveyed downstream. In the device
Between the pair of auxiliary rolls and the pair of correction rolls, there is provided guide means for applying the highest pressing force to the central portion in the sheet width direction from the back side of the sheet loop while guiding the sheet. Sheet alignment device.   The sheet aligning apparatus according to claim 1, wherein the guide unit contacts the sheet only at a central portion in the sheet width direction. The guide means includes
A rotation guide member pivotally supported on the upstream side in the sheet conveying direction and rotatable in the sheet pressing direction;
Biasing means for biasing the rotation guide member in the pressing direction;
The sheet aligning apparatus according to claim 1, further comprising: The guide means includes
3. The sheet aligning apparatus according to claim 1, further comprising an elastic guide member that is supported upstream of the sheet conveying direction and is elastically deformable in the sheet pressing direction.   An image forming unit forms an image on a sheet-like recording medium including the sheet aligning device according to any one of claims 1 to 4 and having the curvature in the conveyance direction corrected by the sheet aligning device. An image forming apparatus.

Images