JP5817478B2 - Paper feeding and conveying apparatus and image forming apparatus - Google Patents

Description

  The present invention feeds the paper stored in a paper storage unit such as a paper feed cassette by a pickup roller, and feeds the above paper through a front guide member that guides the fed paper. The present invention relates to a sheet feeding / conveying apparatus that guides the sheet between the sheet feeding roller and the separation roller, and an image forming apparatus using such a sheet feeding / conveying apparatus. In particular, when the rear end of the paper fed by the pickup roller is carried out of the paper storage unit, the rear end of the paper can be prevented from colliding with the front guide member and generating an impact sound. It has the feature in the point made like this.

  In an image forming apparatus composed of a copying machine, a printer, a facsimile machine, and a combination of these, in general, paper stored in a paper storage unit such as a paper feed cassette is fed by a pickup roller, and the fed paper is fed. When multiple sheets of paper are guided between the paper roller and the separation roller and the multi-feed is separated, the multi-feed paper is separated between the paper feed roller and the separation roller and 2. Description of the Related Art A sheet feeding / conveying device that transports a sheet of paper through a separation roller is used.

  Further, in the above-described paper feeding / conveying device, in order to properly guide the paper fed by the pickup roller from the paper storage unit between the paper feeding roller and the separation roller, for example, a patent As shown in Document 1 and the like, a front guide member for guiding a fed sheet between a sheet feeding roller and a separation roller is provided.

  Here, in the thing of this patent document 1, the front-end | tip of the paper supplied with the pick-up roller from the paper storage part hits the wall surface below the upper surface of a front guide, a noise generate | occur | produces, or a paper is jammed. In order to prevent this, a guide surface is provided on the front guide so as to extend along the paper transport direction from the paper container.

  However, in this patent document 1, the paper fed by the pickup roller from the paper container as described above is guided between the paper feed roller and the separation roller via the front guide member, and this When transporting paper between the paper feed roller and the separation roller, if the trailing edge of the paper fed by the pickup roller is unloaded from the paper storage section, the back edge of the paper is stored in the paper by the waist of the paper. The rear edge of the paper collides with the front guide member and a collision noise is generated. Especially in the case of stiff paper such as thick paper, the rear edge of the paper There has been a problem in that the force urged from the sheet storage portion toward the front guide member is increased, and the rear end portion of the sheet strongly collides with the front guide member to generate a large collision sound.

  Conventionally, in Patent Document 2, in order to suppress abnormal noise generated when a sheet that has passed through the nip portion between the paper feed roller and the inclined member collides with the guide surface of the inclined member, the nip of the inclined member is used. There has been proposed one in which a leading-side inclined surface is provided on the paper-leading side with respect to the section.

  However, the thing of this patent document 2 suppresses the abnormal sound which the paper which passed through the nip part of a paper feed roller and an inclination member as mentioned above collides with the guide surface of an inclination member, When the paper fed from the paper storage unit by the pickup roller as described above is guided between the paper feeding roller and the separation roller via the front guide member, and conveyed through the paper feeding roller and the separation roller. In addition, when the rear end of the fed paper is unloaded from the paper storage unit, it is possible to prevent the rear end of the fed paper from colliding with the front guide member and generating an impact sound. There wasn't.

JP 2009-51668 A JP 2004-284734 A

  The present invention feeds the paper stored in the paper storage unit by a pickup roller, and guides the fed paper between a paper feed roller and a separation roller via a front guide member. It is an object of the present invention to solve the above-described problems in a paper feeding / conveying apparatus that conveys a sheet through a separation roller.

  That is, according to the present invention, in the paper feeding / conveying device as described above, when the rear end of the paper fed by the pickup roller is carried out of the paper storage unit, the rear end of the paper is moved to the front guide. An object of the present invention is to appropriately suppress the occurrence of an impact sound by colliding with a member.

In the paper feeding / conveying device according to the present invention, in order to solve the above-described problem, the paper accommodated in the paper accommodating portion is fed by a pickup roller, and through a front guide member that guides the fed paper, In the paper feeding / conveying apparatus for guiding the paper between the paper feeding roller and the separation roller and transporting the paper through the paper feeding roller and the separation roller, the front guide member is separated from the paper to be conveyed. The front guide member is pushed against the unloaded paper when the trailing edge of the sheet fed from the sheet container by the pickup roller is unloaded from the sheet container. The leading edge of the paper fed by the pickup roller is moved away from the paper to be conveyed or elastically deformed. Until guided between the release roller, said front guide member is prevented from moving or elastically deformed in a direction away from the paper.

  In the paper feeding / conveying apparatus according to the present invention, the front guide member moves away from the paper to be conveyed when the trailing edge of the paper fed by the pickup roller is unloaded from the paper container. However, if it is elastically deformed, even if the rear end portion of the paper carried out from the paper storage portion collides with the front guide member, the force at the time of the collision is relaxed.

  Further, in the paper feeding / conveying device, the front guide member moves or elastically deforms in a direction away from the paper until the leading edge of the paper fed by the pickup roller is guided between the paper feeding roller and the separation roller. Providing a deterring means for deterring, the leading edge of the sheet fed by the pickup roller is appropriately guided between the sheet feeding roller and the separation roller by the front guide member.

  In the image forming apparatus of the present invention, the paper stored in the paper storage unit is fed by the pickup roller, and the paper is fed to the paper feed roller via the front guide member that guides the fed paper. The paper feeding / conveying device as described above was used when the paper was transported between the paper feeding roller and the separation roller.

  In the paper feeding / conveying device of the present invention, the paper fed by the pickup roller from the paper container is guided between the paper feeding roller and the separation roller via the front guide member, and the paper feeding roller and the separation roller When the sheet is conveyed through the gap, the front guide member is provided so as to be movable or elastically deformed in a direction away from the conveyed sheet, and the trailing edge of the sheet fed by the pickup roller is unloaded from the sheet storage unit. At this time, the front guide member moves in a direction away from the conveyed paper or is elastically deformed, so that the force when the rear end of the paper carried out of the paper storage portion collides with the front guide member is reduced. As a result, the rear end of the fed paper collides with the front guide member to suppress the generation of impact noise.

1 is a schematic explanatory diagram illustrating an example of an image forming apparatus that uses a sheet feeding and conveying apparatus according to an embodiment of the present invention. In the paper feeding / conveying apparatus according to the first embodiment of the present invention, (A) shows that the front end of the paper fed from the paper feeding cassette by the pickup roller is connected between the paper feeding roller and the separation roller via the front guide member. FIG. 5B is a schematic explanatory diagram showing a state of being guided between the paper feeding roller and the separation roller. The rear end of the paper guided between the paper feeding roller and the separation roller is carried out of the paper feeding cassette, and the rear end of the paper is front It is the schematic explanatory drawing which showed the state which collides with a guide member. In the paper feeding / conveying apparatus according to the second embodiment of the present invention, (A) shows that the leading edge of the paper fed from the paper feeding cassette by the pickup roller is connected between the paper feeding roller and the separation roller via the front guide member. FIG. 5B is a schematic explanatory diagram showing a state of being guided between the paper feeding roller and the separation roller. The rear edge of the paper guided between the paper feeding roller and the separation roller is carried out of the paper feeding cassette, and the rear edge of the paper is the front. It is the schematic explanatory drawing which showed the state which collides with a guide member. The modified example of the paper feeding / conveying device according to the second embodiment is shown, and when the rear end of the paper guided between the paper feeding roller and the separation roller is discharged from the paper feeding cassette, the front guide member FIG. 6 is a schematic explanatory view showing a state in which is moved to a position where it does not collide with the rear end of the paper. In the sheet feeding / conveying device according to the third embodiment of the present invention, (A) shows that the leading edge of the sheet fed from the sheet feeding cassette by the pickup roller is connected between the sheet feeding roller and the separation roller via the front guide member. FIG. 6B is a schematic explanatory diagram showing a state of being guided between the front guide member and the paper when the rear end of the paper guided between the paper feeding roller and the separation roller is discharged from the paper feeding cassette. It is the schematic explanatory drawing which showed the state moved to the position which does not collide with the rear-end part.

  Next, a sheet feeding / conveying apparatus according to an embodiment of the present invention and an image forming apparatus using the sheet feeding / conveying apparatus will be specifically described with reference to the accompanying drawings. Note that the paper feeding / conveying apparatus and the image forming apparatus according to the present invention are not limited to those shown in the following embodiments, and can be implemented with appropriate modifications within a range not changing the gist thereof.

  In this embodiment, as shown in FIG. 1, the image forming apparatus 1 includes a paper feeding unit 10, a paper conveyance path 20, an image forming unit 30, a fixing unit 40, and a paper discharge unit 50.

  Here, the paper supply unit 10 includes a paper supply cassette 11 that is a paper storage unit for storing the paper S, a paper supply cassette 11, a pickup roller 12, a front guide member 13, a paper supply roller 14, a separation roller 15, and the like. A paper transport device is provided.

  In the paper feeding unit 10, the paper S stacked on the push-up plate 11b in the paper feeding cassette 11 is urged by a spring 11a so that the paper S is pressed against the pickup roller 12. Yes.

  Further, in the paper feeding / conveying device, the pickup roller 12 is rotated to feed the paper S stored in the paper feeding cassette 11 from the paper feeding cassette 11, and the paper fed in this way. S is guided between the paper feed roller 14 and the separation roller 15 via the front guide member 13, and when a plurality of sheets S are fed between the paper feed roller 14 and the separation roller 15, The paper S that has been multi-fed between the paper feed roller 14 and the separation roller 15 is separated, and the single paper S is conveyed to the paper conveyance path 20 through the paper supply roller 14 and the separation roller 15. I am doing so.

  Here, when separating the paper S that has been fed between the paper feed roller 14 and the separation roller 15 as described above, a torque limiter (not shown) is provided on the rotation shaft of the separation roller 15, The rotation limit force of the torque limiter is set to be larger than the friction force between the sheets S, and is set to be smaller than the friction force between the sheet S and the separation roller 15.

  In this way, when a single sheet S is fed between the paper feed roller 14 and the separation roller 15, the frictional force between the single sheet S and the separation roller 15 is as described above. The rotation limit force of the torque limiter is exceeded, and the separation roller 15 also rotates, so that one sheet S is conveyed between the paper feed roller 14 and the separation roller 15. Further, when two or more sheets S are fed between the sheet feeding roller 14 and the separation roller 15, since the frictional force between the sheets S is less than the rotation limiting force of the torque limiter, the separation roller 15 is Only one sheet S that does not rotate and is in contact with the paper feed roller 14 is conveyed between the paper feed roller 14 and the separation roller 15.

  The paper transport path 20 includes an image forming path 20A, a paper discharge / reversing path 20B, a double-sided transport path 20C, and various rollers disposed on these paths.

  The image forming path 20 </ b> A is provided with a conveyance roller 21, a registration roller 22, a secondary transfer roller 34, a fixing unit 40, and the like, and the sheet S sent out between the paper feed roller 14 and the separation roller 15. Passes through the conveying roller 21 located on the downstream side, is temporarily held at the position of the registration roller 22, and is conveyed by the registration roller 22 in accordance with the timing of image formation.

  The paper discharge / reverse path 20B is provided with a paper discharge roller 23A and a reverse roller 23B. In the case of single-sided printing, the paper S that has passed through the image forming path 20A is guided to the paper discharge / reverse path 20B, and is discharged to the paper discharge unit 50 by rotating the paper discharge roller 23A in the forward direction. The On the other hand, in the case of duplex printing, the single-side printed paper S that has passed through the image forming path 20A is guided to the reverse roller 23B side by the switching claw 24, and after the reverse roller 23B rotates in the forward direction, By rotating in the reverse direction, the trailing edge of the sheet S becomes the leading edge and is guided to the duplex conveyance path 20C.

  The image forming unit 30 includes a yellow image forming unit 30Y, a magenta image forming unit 30M, a cyan image forming unit 30C, a black image forming unit 30K, and an intermediate transfer belt. 33 and a secondary transfer roller 34 are provided. Each of the image forming units 30Y, 30M, 30C, and 30K is provided with a photosensitive drum 31 on which a toner image is formed, and around the photosensitive drum 31. Although not shown, a charging device, an exposure device, a developing device, a primary transfer roller, a cleaning device, and the like are provided.

  Here, in the image forming unit 30 described above, the color toner images formed on the photosensitive drums 31 in the image forming units 30Y, 30M, 30C, and 30K are sequentially formed on the intermediate transfer belt 33. The primary transfer is performed, and a full-color toner image is formed on the intermediate transfer belt 33. When the sheet S passes between the intermediate transfer belt 33 and the secondary transfer roller 34, the toner image primarily transferred onto the intermediate transfer belt 33 is transferred to one side of the sheet S.

  The fixing unit 40 is provided with, for example, a heating roller 41 having a heat source and a pressure roller 42 in contact with the heating roller 41, and between the heating roller 41 and the pressure roller 42. The sheet S on which the toner image is formed is heated and pressurized, and the toner image transferred to the sheet S is fixed on the sheet S.

  The sheet S on which the toner image is fixed in this way is guided to the sheet discharge / reverse path 20B, and the sheet S is discharged to the sheet discharge unit 50 in the case of single-sided printing. On the other hand, in the case of duplex printing, the sheet S is guided to the image forming path 20A through the double-sided conveyance path 20C, and the surface opposite to the surface of the sheet S on which the toner image is fixed in the image forming unit 30. In addition, a toner image is formed as described above.

  Here, in the paper feeding / conveying device according to the first embodiment, as shown in FIGS. 2A and 2B, the front guide member 13 is held by the holder 131 and the holder 131 is conveyed. A compression coil spring 132 is provided in a holding guide 133 that is held movably in a direction away from the paper S to be held, and the holder 131 is held on the compression coil spring 132.

  Then, the sheet S is pressed against the pickup roller 12 as described above, and the pickup roller 12 is rotated to feed the sheet S stored in the sheet feeding cassette 11 from the sheet feeding cassette 11. In the stage of guiding between the paper feed roller 14 and the separation roller 15, the holder 131 that holds the front guide member 13 is lifted upward by the compression coil spring 132 as shown in FIG. To be maintained. In this way, the leading edge of the sheet S fed from the sheet feeding cassette 11 comes into contact with the front guide member 13, the sheet S is guided by the front guide member 13, and the leading edge of the sheet S is fed. It is appropriately guided between the roller 14 and the separation roller 15.

  In addition, when the paper S guided between the paper feed roller 14 and the separation roller 15 is conveyed by the paper feed roller 14 as described above, the paper S described above is formed as shown by a broken line in FIG. The sheet S is pulled between the pickup roller 12 and the sheet feeding roller 14, and the sheet S is separated from the front guide member 13.

  When the paper S is conveyed by the paper feed roller 14 as described above and the rear end of the paper S is unloaded from the paper feed cassette 11, the waist of the paper S causes the paper S as shown in FIG. The trailing edge of the sheet S is urged in the direction of rotating downward and collides with the front guide member 13. The force urged in the direction in which the portion pivots downward increases, and the front guide member 13 collides strongly.

  Here, when the rear end portion of the sheet S is urged in the direction of rotating downward and collides with the front guide member 13, in this embodiment, as shown in FIG. The front guide member 13 is pushed downward by the rear end portion of the sheet S colliding with the front guide member 13, whereby the holder 131 holding the front guide member 13 is held against the compression coil spring 132. The force that moves downward in 133 and the rear end of the sheet S collides with the front guide member 13 is alleviated, and the generation of impact sound is suppressed.

  Further, in the paper feeding / conveying device according to the second embodiment, as shown in FIGS. 3A and 3B, the front guide member 13 is mounted on a holding arm 134 that rotates in the vertical direction. A holding member 134 is rotatably held in a vertical direction by a spring member 135 provided below the holding arm 134.

  Further, in this embodiment, the restraining means for restraining the front guide member 13 from moving in the direction away from the paper S until the leading edge of the paper S is guided between the paper feed roller 14 and the separation roller 15. The first lever 136 that holds the end side of the holding arm 134 to which the front guide member 13 is attached is rotatably provided, and the end of the first lever 136 opposite to the holding arm 134 is fed. The second lever 137 is provided on the downstream side in the transport direction of the paper S from between the roller 14 and the separation roller 15 and is rotated and held while the upper side of the second lever 137 is raised. It is provided so as to come into contact with the leading edge of the paper S conveyed between the paper roller 14 and the separation roller 15. Note that the second lever 137 can be held by a spring (not shown) or the like so that the upper side of the second lever 137 is maintained in an upright state so as not to fall on its own.

  Then, the sheet S is pressed against the pickup roller 12 as described above, and the pickup roller 12 is rotated to feed the sheet S stored in the sheet feeding cassette 11 from the sheet feeding cassette 11. In the step of guiding between the paper feed roller 14 and the separation roller 15, as shown in FIG. 3A, the upper side of the second lever 137 is maintained upright as described above, and the above-mentioned first The holding arm 134 to which the front guide member 13 is attached is maintained by being lifted upward by the one lever 136. In this way, the leading edge of the sheet S fed from the sheet feeding cassette 11 comes into contact with the front guide member 13, the sheet S is guided by the front guide member 13, and the leading edge of the sheet S is fed. It is appropriately guided between the roller 14 and the separation roller 15.

  In addition, when the paper S guided between the paper feed roller 14 and the separation roller 15 is conveyed by the paper feed roller 14 as described above, the paper S is changed as shown by a broken line in FIG. The sheet S is pulled between the pickup roller 12 and the sheet feeding roller 14, and the sheet S is separated from the front guide member 13.

  When the paper S is conveyed between the paper feed roller 14 and the separation roller 15 as described above, the leading edge of the paper S is located above the second lever 137 as shown in FIG. The upper side of the second lever 137 is pushed in the direction of being pushed down by the conveyed paper S, and the end of the first lever 136 held on the lower side of the second lever 137 is The second lever 137 is pivoted so as to be lifted upward, and the end of the first lever 136 holding the holding arm 134 to which the front guide member 13 is attached is pivoted downward so that the holding arm It will be in the state away from 134.

  In this state, the paper S is conveyed by the paper feed roller 14, the rear end of the paper S is carried out from the paper feed cassette 11, and the rear end of the paper S is urged in a downward rotating direction. When colliding with the front guide member 13, the holding arm 134 to which the front guide member 13 is attached is rotated downward against the spring member 135, and the rear end portion of the sheet S collides with the front guide member 13. The force is relaxed and the generation of impact sound is suppressed.

  In the paper feeding / conveying device according to the second embodiment, the holding arm 134 is held by the spring member 135 provided below the holding arm 134, but the holding arm 134 is held by the spring member 135. When a downward pulling force is applied, the end side of the holding arm 134 to which the front guide member 13 is attached is rotated downward together with the first lever 136 as shown in FIG. Thus, the front guide member 13 does not collide with the rear end portion of the paper S, and no impact sound is generated.

  Further, in the paper feeding / conveying device according to the third embodiment, as shown in FIGS. 5A and 5B, the front guide member 13 is held by a holder 131, and a holder is provided under the holder 131. An elevating device 138 such as a cylinder for elevating and lowering 131 is provided. The elevating device 138 suppresses the front guide member 13 from moving in a direction away from the paper S until the leading edge of the paper S is guided between the paper feed roller 14 and the separation roller 15. It also has the function as

  Then, the sheet S is pressed against the pickup roller 12 as described above, and the pickup roller 12 is rotated to feed the sheet S stored in the sheet feeding cassette 11 from the sheet feeding cassette 11. At the stage of guiding between the paper feed roller 14 and the separation roller 15, the holder 131 holding the front guide member 13 is lifted by the lifting device 138 as shown in FIG. Try to keep it in position. In this way, the leading edge of the sheet S fed from the sheet feeding cassette 11 comes into contact with the front guide member 13, the sheet S is guided by the front guide member 13, and the leading edge of the sheet S is fed. It is appropriately guided between the roller 14 and the separation roller 15.

  Further, when the paper S guided between the paper feed roller 14 and the separation roller 15 is conveyed by the paper feed roller 14 as described above, the paper S described above is transferred as shown by a broken line in FIG. The sheet S is pulled between the pickup roller 12 and the sheet feeding roller 14, and the sheet S is separated from the front guide member 13.

  When the paper S is conveyed between the paper feed roller 14 and the separation roller 15 as described above, the holder 131 holding the front guide member 13 is moved up and down as shown in FIG. The apparatus is lowered by the apparatus 138, and the front guide member 13 held by the holder 131 is moved to a position where it does not collide with the rear end portion of the paper S carried out from the paper feed cassette 11. In this way, the rear end portion of the paper S carried out from the paper feed cassette 11 does not collide with the front guide member 13, and no impact sound is generated.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Paper feed part 11 Paper feed cassette (paper storage part)
12 Pickup roller 13 Front guide member, 131 Holder, 132 Compression coil spring, 133 Holding guide, 134 Holding arm, 135 Spring member, 136 First lever, 137 Second lever, 138 Lifting device 14 Paper feed roller 15 Separating roller 20 Paper transport Path 21 Conveying roller 22 Registration roller 30 Image forming unit 40 Fixing unit 50 Paper discharge unit S Paper

Claims (4)

The paper stored in the paper storage unit is fed by the pickup roller, and the paper is guided between the paper feeding roller and the separation roller through a front guide member that guides the fed paper. In the paper feeding / conveying apparatus that conveys the paper through between the roller and the separation roller, the front guide member is provided so as to be movable or elastically deformed in a direction away from the paper to be conveyed, and a paper storage unit is provided by the pickup roller. When the trailing edge of the sheet fed from the sheet is unloaded from the sheet container, the front guide member is pushed by the unloaded sheet and moved or elastically deformed in a direction away from the sheet to be conveyed. Until the leading edge of the paper fed by the pickup roller is guided between the paper feeding roller and the separation roller, Sheet feed conveying device characterized in that it does not move or elastically deformed et away direction. 2. The paper feeding / conveying apparatus according to claim 1 , wherein the front guide member is moved away from the paper until a leading edge of the paper fed by the pickup roller is guided between the paper feeding roller and the separation roller. A sheet feeding / conveying apparatus, comprising: a deterring unit that deters movement or elastic deformation. The paper stored in the paper storage unit is fed by the pickup roller, and the paper is guided between the paper feeding roller and the separation roller through a front guide member that guides the fed paper. In the paper feeding / conveying device that conveys the paper between the roller and the separation roller, the front guide member is provided so as to be movable away from the paper conveyed by the moving device, and is fed by the pickup roller. When the trailing edge of the discharged paper is carried out of the paper storage unit, the front guide member is moved to a position where it does not collide with the paper carried out of the paper storage unit by the moving device. apparatus.   The paper stored in the paper storage unit is fed by the pickup roller, and the paper is guided between the paper feeding roller and the separation roller through a front guide member that guides the fed paper. An image forming apparatus using the sheet feeding / conveying device according to any one of claims 1 to 3 for conveying a sheet between a roller and a separation roller.

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