JP3653965B2 - Sheet-like member conveyance direction switching mechanism and image forming apparatus provided with this mechanism - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mechanism for switching the conveyance direction when conveying a sheet-like member, and in particular, switching of the conveyance direction of a sheet-like member such as a recording sheet suitable for use in an image forming apparatus such as a copying machine or a printer. It relates to the mechanism.
[0002]
[Prior art]
A switching mechanism for switching the recording sheet conveyance direction in a conventional copying machine will be described with reference to FIG. In the transport direction switching mechanism shown in FIG. 11A, the recording sheet s from the fixing roller pair 91 passes directly when the recording sheet s goes straight to the outlet 100 and is discharged straight from the discharge roller pair 92, and the recording sheet. A passage 102 through which s travels toward the reversing roller pair 93 and a passage 103 through which the recording sheet subjected to front / back conversion travels toward the outlet 100 are formed. The paper discharge roller pair 92 includes a roller 92a made of resin and a roller 92b made of rubber.
[0003]
When the switching guide 81 provided in the switching mechanism is rotated about the rotation shaft 82 in the direction of the arrow p in the figure, the guide surface 84 comes into contact with the stopper portion 97 and stops, closing the passage 101 and closing the passage. When 102 is opened and the guide surface 85 is rotated in the r direction, the guide surface 85 comes into contact with the stopper portion 98 as indicated by the broken line in the figure and stops, and the passage 102 is closed and the passage 101 is opened. Thereby, the conveyance direction of the recording sheet can be switched between the passages 101 and 102. Such a switching mechanism for the recording sheet conveyance direction forms an image on one side of the recording sheet when the recording sheet is converted into the front and back sides and discharged to an external discharge tray, or to form an image on both sides of the recording sheet. This is necessary when the recorded sheet is conveyed to the other side when it is conveyed to an automatic reversing paper feeding unit (ADU).
[0004]
The operation of converting the front and back of the recording sheet by this switching mechanism and inverting and discharging will be described with reference to FIG. After the switching guide 81 is switched so as to close the passage 101 and open the passage 102, the recording sheet that has emerged from the fixing roller pair 91 in the direction of the arrow a as indicated by the wavy line enters the passage 102 and enters the switching guide 81. It hits the guide surface 85 and proceeds along the guide surface 85 in the direction of the arrow b, and enters the reverse roller pair 93. Thereafter, when the reverse roller pair 93 is rotated in the reverse direction, the recording sheet enters the passage 103 with the trailing edge up to that point as the leading edge, proceeds in the direction of the arrow c as indicated by the one-dot chain line, and hits the guide surface 86 of the switching guide. Advancing in the d direction along the surface 86, exits from the outlet 100, and is discharged to the outside by a pair of discharge rollers 92. In this way, the recording sheet passes through the passage 102, the reverse roller pair 93, and the passage 103, so that the front and back of the recording sheet are converted, and the recording sheet is reversed and discharged from the discharge roller pair 92 to an external discharge tray or the like.
[0005]
[Problems to be solved by the invention]
However, as described above, every time the recording sheet conveyance direction is switched between the passage 101 and the passage 102, the switching guide 81 abuts against the stopper portions 97 and 98, so that sudden sound is generated. Compared with the case of straight sheet discharge through the normal path 101, when reverse sheet discharge is performed, the recording sheet conveyance path length becomes longer, so the line conveyance speed is increased to avoid productivity reduction and conveyance A quick switching operation of the passage is required. If the switching operation is fast, the rotational energy during rotation of the switching guide also increases, and the sudden sound generated when the switching guide collides with the stopper portion increases.
[0006]
Further, when the recording sheet is reversed and discharged, when the recording sheet passes through the passage 103 and proceeds in the direction of arrow d in FIG. 11B, the arrow of the recording sheet collides with the vicinity of the exit 94 a of the guide plate 94. Proceeding in the direction e, it collides with the resin roller 92a near the nip portion of the paper discharge roller pair 92. As described above, when the line conveyance speed is high, the kinetic energy of the recording sheet conveyed increases, so that the sudden sound generated at the time of the collision increases. Further, when the recording sheet collides in this way, the leading end is easily bent.
[0007]
In office automation equipment such as copiers, in order to reduce noise in the office, further noise reduction measures are desired. At the time of collision with the stopper of the switching guide as described above, a guide plate or resin There is a need for countermeasures against sudden sound that occurs when a roller collides.
[0008]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a conveyance direction switching mechanism capable of preventing sudden sound that occurs at the time of switching the conveyance direction of a recording sheet or at the time of reversed paper discharge, and to reduce the noise of an image forming apparatus such as a copying machine. That is.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the sheet-like member conveyance direction switching mechanism of the present invention includes a first passage through which the sheet-like member is conveyed and the sheet-like member in a direction different from the first passage. By rotating to open one of the second passage and the first and second passages that are passed when being conveyed, the conveying direction of the sheet-like member is changed between the first passage and the first passage. A switching guide for switching to the two passages, a stopper provided against the switching guide, and a stopper portion that contacts the switching guide when the switching guide is rotated to switch the transport direction, and the switching guide And a buffer member provided between the stopper portion.
[0010]
According to the present invention, since the buffer member exists between the switching guide and the stopper portion, even if the switching guide rotates when the passage is switched, it does not directly contact the stopper portion. The impact caused by the contact is absorbed and buffered by the buffer member. Thereby, it is possible to prevent the occurrence of sudden sound at the time of switching the conveyance direction of the sheet-like member.
[0011]
The buffer member may be provided on the switching guide or the stopper portion. Moreover, you may provide in both a switching guide and a stopper part.
[0012]
The buffer member may be made of foamable EPDM, thermoplastic elastomer, thermoplastic resin, silicon gel, or rubber. The impact at the time of switching is efficiently absorbed and buffered by the viscoelasticity of these buffer members.
[0013]
Another sheet-like member conveyance direction switching mechanism according to the present invention includes a first passage that passes when the sheet-like member is conveyed to an outlet, and a sheet-like member that is conveyed in a direction different from the first passage. A second passage that passes through the second passage, and a sheet-like member that has passed through the second passage is configured to be able to pass through when changing the transport direction toward the outlet. A passage, and first, second, and third guide surfaces that define the first, second, and third passages, respectively, and are configured to open one of the first and second passages. A switching guide that switches the conveying direction of the sheet-like member between the first passage and the second passage by moving; and a guide portion that defines the first passage together with the first guide surface of the switching guide; , A third of the switching guide in the third passage From the guide surface comprises a first deformable member projecting toward said outlet.
[0014]
According to the present invention, when the sheet-like member is conveyed from the guide surface of the switching guide to the outlet in the third passage, the first deformable member protruding toward the outlet is elastically deformed and the sheet-like member is deformed. The sheet-like member can be prevented from colliding with the guide portion of the first passage in the vicinity of the outlet. Thereby, the sudden sound produced at the time of the collision with the guide part of the sheet-like member in the exit vicinity can be prevented. Moreover, the bending of the front-end | tip of a sheet-like member by a sheet-like member colliding can be prevented.
[0015]
The projecting portion of the first deformable member includes a curved portion that is curved so that the sheet-like member faces the outlet. With this curved portion, the sheet-like member can be directed to the outlet more smoothly and reliably.
[0016]
Further, it is preferable that the curved portion of the first deformable member has an arc shape having a radius of approximately 3 mm to 100 mm.
[0017]
Moreover, the protrusion part of a said 1st deformable member equips the front end side of the said curve part with a linear part, and can turn a sheet-like member to an exit more reliably. The length of the straight portion is preferably about 50 mm at the maximum.
[0018]
In addition, the third guide surface in the third passage has a concave curved shape, and the first deformable member protrudes along the curved shape, so that the deformable member becomes the third guide surface. It can be configured to project smoothly toward the outlet.
[0019]
Further, a discharge roller pair for further conveying and discharging the sheet-like member that has exited from the outlet is provided in the vicinity of the outlet, and the first deformable member extends to the vicinity of the discharge roller pair. it can. According to this configuration, since the first deformable member extends to the vicinity of the discharge roller pair, it is possible to prevent the sheet-like member from smoothly entering the nip portion of the discharge roller pair and colliding with the discharge roller pair. Thereby, sudden sound generated when the sheet-like member collides with the discharge roller pair can be prevented.
[0020]
Further, the discharge roller pair may be composed of a rubber roller and a resin roller, and the first deformable member may extend to the vicinity of the rubber roller. According to this configuration, even when the sheet-shaped member collides with the pair of reverse discharge rollers, the collision with the resin roller having a large sudden sound is prevented and the rubber roller collides. Thereby, since this impact is buffered by the viscoelasticity of the rubber roller, a large sudden sound can be prevented.
[0021]
Further, the first deformable member can be formed integrally with the switching guide.
[0022]
In addition, a second deformable member is further provided along the guide portion of the first passage, and the distal end portion of the second deformable member extends to the vicinity of the distal end portion of the first deformable member. Can be configured. Since the tip portions of both deformable members can be in contact with each other, the portion protruding from the third guide surface of the first deformable member has an appropriate curved shape and has passed through the third passage. Can be guided to the outlet and the discharge roller pair.
[0023]
In addition, a buffer member can be provided between the guide portion of the first passage and the second deformable member. Accordingly, even if the sheet-like member passing through the third passage hits the first deformable member in the vicinity of the outlet and presses the second deformable member, the impact is absorbed, so that sudden sound due to the collision can be prevented.
[0024]
A buffer member may be provided between the third guide surface of the switching guide and the first deformable member. Thereby, even if the sheet-like member is conveyed through the third passage and hits the third surface of the switching guide, the impact is absorbed, so that sudden sound due to the collision can be prevented.
[0025]
The first and second first deformable members may be polyethylene terephthalate, hard vinyl chloride stretched film, stretched polystyrene, soft polyethylene, or polypropylene stretched film with a thickness in the range of 30 μm to 350 μm. preferable. If the deformable member is less than 30 μm, it will be easily deformed and the effect of preventing sudden sound at the time of collision will not be expected, and if it exceeds 350 μm, a large sudden sound will occur when the sheet-like member collides with the deformable member itself This is not preferable. In addition, the 1st deformable member which consists of these materials can be fixed to the 3rd guide surface of a switching guide by methods, such as adhesion | attachment.
[0026]
Further, according to another sheet-like member conveyance direction switching mechanism of the present invention, the sheet-like member is conveyed in a direction different from the first passage through which the sheet-like member passes when being conveyed to the outlet. A second passage that passes through the second passage, and a sheet-like member that has passed through the second passage can pass through when changing the transport direction toward the outlet. 3 passages and first, second, and third guide surfaces that define the first, second, and third passages, respectively, and open one of the first and second passages. A switching guide for switching the conveying direction of the sheet-like member between the first passage and the second passage by rotating in such a manner, and a guide for defining the first passage together with the first guide surface of the switching guide. And along the guide portion of the first passage Is comprises a deformable member which projects towards the outlet.
[0027]
According to the present invention, when the sheet-like member is conveyed from the third guide surface of the switching guide to the outlet in the third passage, the sheet-like member is directed toward the outlet along the guide portion of the first passage. While contacting the protruding deformable member, the deformable member is elastically deformed and directs the sheet-shaped member toward the outlet, and the sheet-shaped member can be prevented from colliding with the guide portion of the first passage in the vicinity of the outlet. Thereby, the sudden sound which arises at the time of the collision with the guide part of the sheet-like member in the exit vicinity can be prevented. Moreover, the bending of the front-end | tip of a sheet-like member by a sheet-like member colliding can be prevented.
[0028]
Further, a discharge roller pair for further conveying and discharging the sheet-like member that has exited from the outlet is provided in the vicinity of the outlet, so that the sheet-like member that has passed through the third passage is guided to the discharge roller. The deformable member may be configured to extend to the vicinity of the discharge roller pair. According to this configuration, since the deformable member extends to the vicinity of the discharge roller pair, it is possible to prevent the sheet-like member from smoothly entering the nip portion of the discharge roller pair and colliding with the discharge roller pair. Thereby, sudden sound generated when the sheet-like member collides with the discharge roller pair can be prevented.
[0029]
Further, a reversing roller pair is provided in a direction extending toward the conveying side of the second passage, and the sheet-like member that has passed through the second passage is conveyed toward the third passage by the reversing roller pair, and then from the outlet. It can be configured such that the front and back of the sheet-like member are reversed and discharged. With this configuration, the sheet-like member conveyance direction switching mechanism can be configured as a sheet-like member reverse discharge mechanism.
[0030]
In addition, by configuring the image forming apparatus to include the above-described sheet-like member conveyance direction switching mechanism, it is possible to contribute to noise reduction measures in the image forming apparatus.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. First, an electrophotographic image forming apparatus to which the sheet-like member conveyance direction switching mechanism according to an embodiment of the present invention can be applied will be described with reference to FIG. FIG. 1 is a schematic side view of an electrophotographic image forming apparatus, which mainly shows a recording sheet conveyance path. The image formed by this image forming apparatus is a black and white image.
[0032]
The image forming apparatus of FIG. 1 is provided with an automatic reversing paper feeding unit (ADU) for recording on the back side after forming an image on the recording sheet, and a mechanism for converting the recording sheet into a reverse side and reversely discharging it. A switching mechanism for the recording sheet conveyance direction is provided in the area A for these ADUs and the reverse discharge mechanism.
[0033]
The image forming apparatus shown in FIG. 1 includes a photosensitive drum 1 on which a photoconductive photosensitive layer is formed, and a charge charger 8 disposed above the photosensitive drum 1. The photosensitive drum 1 that is uniformly and sequentially charged by the charging charger 8 while rotating in the direction of the arrow q is exposed and irradiated from the direction of the arrow b in the figure by a scanning beam from an original table (not shown) or the like. An image is formed on the photosensitive drum 1. As described above, an image from the document table is formed as an electrostatic latent image on the photosensitive drum 1 and is developed by the developing device 5 to become a toner image as the photosensitive drum 1 rotates in the q direction.
[0034]
On the other hand, the recording sheet s on the paper feed tray 4 is fed in the direction of the arrow t by the roller 4 a and is conveyed to the lower part of the photosensitive drum 1 by the roller pair 19 and 20. A toner image formed on the photosensitive drum 1 is transferred to the recording sheet by the transfer pole 6. The recording sheet onto which the toner image has been transferred in this manner is conveyed by the conveying device 3 to the fixing roller pair 11 of the fixing device 2. Further, the photosensitive drum 1 having the toner image transferred to the recording sheet is further rotated in the q direction, and the residual toner on the photosensitive drum 1 is cleaned by the cleaning device 7, and the photosensitive drum 1 is charged by the charging charger 8 for the next image formation. Charged again.
[0035]
Next, the outline of the conveyance of the recording sheet having the toner image fixed by the fixing device 2 will be described. The recording sheet from the fixing roller pair 11 passes through the passage 41 as it is and is discharged to the outside by, for example, a discharge roller pair 9 to a discharge tray (not shown). On the other hand, when the recording sheet is reversed and discharged in reverse, the switching guide 21 (shown in FIGS. 2 to 6) is switched to close the passage 41 and open the passage 42. Then, the recording sheet from the fixing roller pair 11 passes through the passage 42 and enters the reversing roller pair 12 and is conveyed downward in the drawing. The recording sheet is stopped halfway, and then the reversing roller pair 12 is rotated in reverse. As a result, the recording sheet advances in the direction of the arrow v shown by the wavy line with the rear end so far leading, and is reversely discharged from the pair of discharge rollers 9 through the passage 43.
[0036]
In addition, when an image is formed on one side of a recording sheet and then formed on the other side, the recording sheet is inverted as follows by an ADU composed of a plurality of roller pairs or the like. Image formation is performed. That is, the recording sheet having the toner image fixed on one surface passes through the passage 42 and is sent to the roller pair 15 by the roller pairs 12, 13 and 14.
[0037]
The roller pair 15 is then rotated in the reverse direction, and the recording sheet advances in the direction of the arrow w with the trailing edge of the recording sheet as the leading edge. The roller pair 16, 17, 18, 19 and 20 lowers the photosensitive drum 1 described above. It is conveyed to. At this time, the other surface of the recording sheet on which no image is formed is positioned on the upper surface side of the drawing, and the toner image is transferred from the photosensitive drum 1 to the other surface in the same manner as described above. Thereafter, an image is formed on the other surface through the fixing device 2. The recording sheet on which the image is formed on both sides in this manner is discharged to the outside through the passage 41 and the discharge roller pair 9.
[0038]
Next, in the image forming apparatus shown in FIG. 1, the first to first recording sheet conveyance direction switching mechanisms provided in the area A including the passages 41, 42, and 43 for the ADU and the reverse discharge mechanism as described above. The fifth embodiment will be described.
[0039]
<First Embodiment>
FIG. 2 is a side view of the recording sheet conveyance direction switching mechanism according to the first embodiment. The switching mechanism includes a switching guide 21 disposed so as to be surrounded by a first guide portion 34, a second guide portion 35, and a third guide portion 36 provided in the region A of FIG. The switching guide 21 is rotated in the p and r directions in FIG. 2 by a rotating shaft 22 that is driven to rotate by a rotation driving source (not shown). The switching guide 21 includes a first guide surface 24 that is substantially linear, a second guide surface 25 that is configured as a concave curve on the reversing roller pair 12 side, and a third guide surface that is configured as a concave curve. 26. The switching guide can be made of a metal material or a resin material.
[0040]
A first passage 41 is defined by the first guide portion 34 and the first guide surface 24 of the switching guide 21, and a second passage 42 is defined by the second guide portion 35 and the second guide surface 25. In addition, a third passage 43 is defined by the third guide portion 36 and the third guide surface 26. Further, a stopper portion 37 that contacts the switching guide 21 is provided in an arc shape on the first guide portion 34 side so as to protrude toward the passage 41 side closer to the fixing roller pair 2, and also on the second guide portion 35 side. A stopper portion 38 that comes into contact with the switching guide 21 is provided in an arc shape so as to protrude toward the passage 42 toward the side closer to the fixing roller pair 2.
[0041]
On the first guide surface 24 of the switching guide 21, a buffer member 28 is provided by adhesion or the like at a position facing the stopper portion 37 and in contact with the stopper portion 37, and on the second guide surface 25. In addition, a buffer member 29 is provided by bonding or the like at a position facing the stopper portion 38 and in contact with the stopper portion 38. The buffer members 28 and 29 are made of a deformable material having viscoelastic characteristics. As a material of such a buffer member, foamable EPDM, thermoplastic elastomer, thermoplastic resin, silicon gel or rubber is preferable. In this example, specifically, a commercially available product name “Epto Sealer” (manufactured by Nitto Denko Corporation) However, the trade name “Elastage” (manufactured by Tosoh Corporation), the trade name “Inoac Industrial Foam Rubber Sponge” (manufactured by Inoue MTP Co., Ltd.), and the like can also be used.
[0042]
Next, the operation of the recording sheet conveyance direction switching mechanism as described above will be described. First, in a state where the switching guide 21 is in the wavy line position in FIG. 2 and the passage 42 is closed and the passage 41 is opened, a rotational drive source (not shown) rotationally drives the rotary shaft 22 based on a switching signal instruction. Then, the switching guide 21 rotates in the p direction, and the buffer member 28 of the switching guide 21 comes into contact with the stopper portion 37 and stops there. As a result, as shown in FIG. 2, the first passage 41 is closed and the second passage 42 is opened, and the recording sheet s from the fixing roller 2 passes through the second passage 42 toward the reversing roller pair 12. be able to.
[0043]
Next, by the rotational drive of the rotating shaft 22 based on another instruction of the switching signal, the switching guide 21 rotates in the r direction, and the buffer member 29 of the switching guide 21 contacts the stopper portion 38 and stops there. As a result, the second passage 42 is closed and the first passage 41 is opened as indicated by the wavy line in FIG. 2, and the recording sheet s from the fixing roller 2 passes through the first passage 41, and the outlet 10 and It can go to the discharge roller pair 9. In this way, the recording sheet conveyance direction can be changed by switching the passage through which the recording sheet s passes between the first passage 41 and the second passage by the switching guide 21.
[0044]
According to the switching mechanism according to the first embodiment as described above, even if the switching guide 21 rotates at the time of switching the passage, it does not come into direct contact with the stopper portions 37 and 38 and the buffer provided in the switching guide 21. Since the members 28 and 29 collide with the stopper portions 37 and 38, respectively, the impact is efficiently absorbed and buffered by the viscoelasticity of the buffer members 28 and 29. This prevents the occurrence of sudden sound when the recording sheet conveyance direction is switched. Therefore, further noise reduction can be achieved in the image forming apparatus shown in FIG.
[0045]
In addition, when reverse discharge or double-sided image formation is performed in the image forming apparatus as described above, the line conveyance speed is increased to avoid a decrease in productivity, and a quick switching operation of the conveyance path is required, but the switching operation is quick. Even if the rotational energy during rotation of the switching guide 21 increases, the shock-absorbing members 28 and 29 of the switching guide 21 come into contact with the stopper portions 37 and 38, so that the impact is absorbed by the shock-absorbing members 28 and 29 and becomes large. No sudden sound is generated. Accordingly, it is not necessary to reduce the line conveyance speed in the image forming apparatus in order to reduce sudden sound at the time of switching, and it is possible to provide an image forming apparatus that achieves further noise reduction while maintaining high productivity. it can.
[0046]
<Second Embodiment>
FIG. 3 shows a recording sheet conveyance direction switching mechanism according to the second embodiment. Since this switching mechanism is configured in the same manner as the switching mechanism shown in FIG. 2 except for the configuration of the buffer member, the same parts are denoted by the same reference numerals, and description thereof is omitted.
[0047]
The switching mechanism shown in FIG. 3 is configured such that the buffer member provided on the guide member 21 is formed in a circular shape. That is, as shown in FIG. 3, the shaft 46 is fixed to the narrow portion of the switching guide 24 between the first guide surface 24 and the second guide surface 25 at a position facing the stopper portions 37 and 38. A circular buffer member 45 is fitted and fixed to the shaft 46. The outer circumferential surface of the circular buffer member 45 protrudes from the first guide surface 24 and the second guide surface 25 of the switching guide 21, and when the switching guide 21 rotates, Abut. The circular shock-absorbing member 45 prevents sudden sound generation caused by a collision when the recording sheet conveyance direction is switched, as in FIG.
[0048]
Further, according to the noise measurement by the present inventors, the same conditions are applied to the image forming apparatus having the conventional switching mechanism as shown in FIG. 11 and the image forming apparatus having the switching mechanism according to the first and second embodiments. In the apparatus of the first and second embodiments, the sudden sound generated when switching the recording sheet conveyance direction in the apparatus of the first and second embodiments is -5 [dB (A)] APL, respectively. The effect of the present invention was specifically confirmed.
[0049]
<Third Embodiment>
FIG. 4 shows a recording sheet conveyance direction switching mechanism according to the third embodiment. Since this switching mechanism is configured in the same manner as the switching mechanism shown in FIG. 2 except for the configuration of the buffer member, the same parts are denoted by the same reference numerals, and description thereof is omitted.
[0050]
The switching mechanism shown in FIG. 4 is provided with a buffer member on the stopper side. That is, as shown in FIG. 4, the buffer member 51 formed in an arc shape is provided on the arc-shaped surface of the stopper portion 37 by adhesion or the like, and the buffer member 52 formed in the arc shape is similarly provided in the stopper portion. It is provided on 38 arcuate surfaces by adhesion or the like. Even when the contact portion of the switching guide 21 contacts the stopper portions 37 and 38 when the switching guide 21 rotates, the buffer members 51 and 52 provided on the stopper portions 37 and 38 switch the recording sheet conveyance direction. Sudden sound due to a collision at the time is prevented in the same manner as in FIG. 2, and the same effect can be obtained.
[0051]
Further, according to the noise measurement similar to that in the first and second embodiments of the present inventors, in the apparatus of the present embodiment, it occurred when switching the recording sheet conveyance direction in the conventional apparatus. The sudden sound was greatly reduced to -5 [dB (A)] APL, and the effect of the present invention was specifically confirmed.
[0052]
2 to 4, the buffer member is provided in one of the switching guide 21 and the stopper portions 37 and 38, but may be provided in both. In addition, the stopper portions 37 and 38 are formed in a convex arc shape, but in the present invention, the stopper portion is not limited to this, and may have other shapes, may be linear, or the first guide portion. 34 and the second guide part 35 may be provided directly.
[0053]
<Fourth embodiment>
FIG. 5 is a side view of the recording sheet conveyance direction switching mechanism according to the fourth embodiment. This switching mechanism is obtained by adding a configuration for preventing sudden sound generated when the recording sheet is conveyed through the third passage 43 and reversed and discharged to the configuration of FIG. For this reason, the same code | symbol is attached | subjected to the part similar to FIG. 2, and the description is abbreviate | omitted.
[0054]
In the switching mechanism of FIG. 5, a deformable member 61 is fixed to the concave curved third guide surface 26 of the switching guide 21 by adhesion or the like. The deformable member 61 is provided along the curve of the third guide surface 26 and protrudes from the end of the guide surface 26 toward the outlet 10. A curved portion 61a is formed in the protruding portion, and the curved portion 61a extends to the vicinity of the discharge roller pair 9 while maintaining a predetermined curve.
[0055]
The deformable member 61 is made of elastically deformable polyethylene terephthalate or the like, and as this material, a stretched film of hard vinyl chloride, stretched polystyrene, soft polyethylene, or a polypropylene stretched film can be used. The discharge roller pair 9 includes a roller 9b made of resin and a roller 9c made of rubber, and the resin roller 9b and the rubber roller 9c come into contact with each other to form a nip portion 9a.
[0056]
Next, the operation of this switching mechanism will be described. When the recording sheet is conveyed from the pair of reversing rollers 12 to the third passage 43 for reversing and discharging the recording sheet, the recording sheet hits the deformable member 61 provided on the third guide surface 26 and then travels thereon. . When the recording sheet further advances from the end of the third guide surface 26 toward the outlet 10, the curved portion 61 a of the deformable member 61 is elastically deformed toward the outlet vicinity 34 a of the first guide portion 34. However, the recording sheet advances along the curved portion 61a, exits from the outlet 10, and the leading end portion st (indicated by a wavy line in FIG. 5) of the recording sheet is naturally guided to the nip portion 9a of the discharge roller pair 9 for recording. The sheet is discharged in reverse. In this way, the recording sheet does not collide with the guide portion 34 by the curved portion 61a, but naturally changes its direction and is guided to the nip portion 9a.
[0057]
As described above, the recording sheet does not first collide with the exit vicinity 34a of the guide portion 34 and is discharged while the recording sheet is conveyed to the discharge roller pair 9 through the third passage 43. Since the roller pair 9 does not collide with the resin roller 9b having a large sudden sound, it is possible to prevent sudden sound due to the collision at these portions. Therefore, according to the switching mechanism according to the present embodiment, it is possible to prevent the occurrence of sudden sound when the switching guide 21 switches the recording sheet conveyance direction between the first path 41 and the second path 42. Combined with the effect, further noise reduction can be achieved in the image forming apparatus shown in FIG.
[0058]
Further, when reverse discharge is performed in the image forming apparatus as described above, the line conveyance speed is increased to avoid a decrease in productivity, and the recording sheet guide 34 is increased even if the kinetic energy of the conveyed recording sheet increases. Since collision with the roller pair 9 can be avoided, sudden sound does not occur due to collision. Therefore, it is not necessary to reduce the line conveyance speed in the image forming apparatus in order to reduce sudden sound during conveyance in the third passage, and the image forming apparatus achieves further noise reduction while maintaining high productivity. Can be provided.
[0059]
Further, since the collision at the leading end of the recording sheet can be avoided, the leading end of the recording sheet can be prevented from being bent in the vicinity of the outlet 10. Therefore, according to the image forming apparatus having the switching mechanism according to the present embodiment, it is possible to provide high-quality electrophotography.
[0060]
Further, according to the noise measurement by the present inventors, noise measurement is performed under the same conditions for the image forming apparatus having the conventional switching mechanism as shown in FIG. 11 and the image forming apparatus having the switching mechanism according to the fourth embodiment. As a result, the sudden sound generated when the recording sheet collided with the guide surface 34 in the conventional apparatus was 77 [dB (A)] APL, whereas in the apparatus of the fourth embodiment, 72 was used. [DB (A)] APL was greatly reduced, and the effects of the present invention were specifically confirmed. In this case, the curved portion 61a of the deformable member 61 in FIG. 5 was an arc having a radius of 18 mm.
[0061]
The thickness of the deformable member 61 is preferably in the range of 30 μm to 350 μm. If the deformable member 61 is less than 30 μm, it easily deforms in the curved portion 61a of the protruding portion and collides with the vicinity of the exit 34a of the first guide portion 34, and the effect of preventing sudden sound cannot be expected. On the other hand, if the thickness exceeds 350 μm, the deformable member 61 is hardly elastically deformed. As a result, a large sudden sound is generated when the recording sheet collides with the deformable member itself, which is not preferable.
[0062]
<Fifth embodiment>
FIG. 6 shows a recording sheet conveyance direction switching mechanism according to the fifth embodiment. This switching mechanism is configured by adding a configuration for preventing sudden sound that occurs when the recording sheet is conveyed through the third passage 43 and reversed and discharged to the configuration of FIG. This is basically the same as FIG. For this reason, the same code | symbol is attached | subjected to the part similar to FIG.4 and FIG.5, and the description is abbreviate | omitted.
[0063]
In the switching mechanism of FIG. 6, the deformable member 62 has a curved portion 62a and a straight portion 62b at the protruding portion. The linear portion 62b is located on the tip side and extends to the vicinity of the nip portion 9a of the discharge roller pair 9. According to this switching mechanism, the leading end portion st (shown by a wavy line in FIG. 6) of the recording sheet does not first collide with the exit vicinity portion 34a of the guide portion 34, and does not contact the nip portion 9a of the discharge roller pair 9. Since the recording sheet is guided in a natural state by the straight portion 62b and does not collide with the resin roller 9b having a large sudden sound, it is possible to prevent sudden sound due to the collision in these portions as in FIG. Therefore, the same effect as in the case of FIG. 5 can be obtained.
[0064]
Further, according to the noise measurement similar to that in the fourth embodiment of the present inventors, the sudden sound generated when the recording sheet collides with the guide surface 34 in the conventional apparatus is 77 [dB (A). In contrast to the APL, the apparatus according to the fifth embodiment is greatly reduced to 70 [dB (A)] APL, and the effect of the present invention was specifically confirmed. In this case, the curved portion 62a of the deformable member 62 in FIG. 6 is an arc having a radius of 18 mm, bent 45 degrees at a position 7 mm from the tip of the deformable member, and the length of the straight portion 62b is 7 mm.
[0065]
The deformable members 61 and 62 may extend in the vicinity of the rubber roller (the rubber roller 9c in FIGS. 5 and 6) when the rollers of the discharge roller pair 9 are made of a cushioning material such as rubber. This is because even if the leading edge of the recording sheet collides with the rubber roller, the impact is buffered by the viscoelasticity of the rubber, and the sudden sound is small.
[0066]
<Sixth embodiment>
FIG. 7 is a side view of a recording sheet conveyance direction switching mechanism according to the sixth embodiment. This switching mechanism is obtained by adding a second deformable member 71 to the first passage 41 in the configuration of FIG. For this reason, the same code | symbol is attached | subjected to the part similar to FIG. 5, and the description is abbreviate | omitted.
[0067]
In the switching mechanism of FIG. 7, the deformable member 71 is fixed to the first guide portion 34 by the adhesive portion 71 b of the first guide portion 34 by adhesion along the first guide portion 34 of the first passage 41. This deformable member 71 passes through the outlet vicinity portion 34a of the first guide portion 34 toward the outlet 10, and the distal end portion 71a is provided on the third guide surface 26 of the switching guide 21 as in FIG. The deformable member 63 extends to the vicinity of the discharge roller pair 9 while being in contact with the tip 63a. Both the tip portions 71a and 63a are in contact with each other so as to press each other. As a result, the portion of the deformable member 63 protruding from the third guide surface 26 has an appropriate radius R so that the leading end portion st of the recording sheet is naturally guided to the nip portion 9a or the rubber roller 9c. For this reason, in the switching mechanism of FIG. 7, the same effect as that of FIG. 5 can be obtained. The deformable member 71 is made of elastically deformable polyethylene terephthalate or the like, but as this material, a stretched film of hard vinyl chloride, stretched polystyrene, soft polyethylene, or a stretched polypropylene film can be used.
[0068]
<Seventh embodiment>
FIG. 8 is a side view of the recording sheet conveyance direction switching mechanism according to the seventh embodiment. This switching mechanism is obtained by adding a buffer member between the first guide portion 34 of the first passage 41 and the second deformable member 71 to the configuration of FIG. For this reason, the same code | symbol is attached | subjected to the part similar to FIG. 7, and the description is abbreviate | omitted.
[0069]
The switching mechanism of FIG. 8 is provided with a buffer member 81 between the first guide portion 34 of the first passage 41 and the deformable member 71 and near the outlet vicinity portion 34a. Even when the recording sheet is conveyed through the third passage and the leading end st thereof is directed toward the outlet 10, the impact is applied even if the leading end 63a of the deformable member 63 presses the leading end 71a of the deformable member 71 toward the outlet vicinity 34a. Can be absorbed by the buffer member 81, and sudden sound due to collision can be prevented. In addition, as a material of the buffer member 81, the thing similar to the buffer members 28 and 29 of FIG. 2 can be used.
[0070]
<Eighth embodiment>
FIG. 9 is a side view of a recording sheet conveyance direction switching mechanism according to the eighth embodiment. This switching mechanism is obtained by adding a buffer member between the third guide surface 26 of the first passage 43 and the deformable member 63 to the configuration of FIG. For this reason, the same code | symbol is attached | subjected to the part similar to FIG. 8, and the description is abbreviate | omitted.
[0071]
The switching mechanism of FIG. 9 includes a buffer member 82 between the third guide surface 26 of the switching guide 21 and the deformable member 63 in the third passage 43. Even if the recording sheet is conveyed from the pair of reverse rollers 12 through the third path 43 and the leading end st collides with the deformable member 63 on the third guide surface 26, the shock is absorbed by the buffer member 82. And can prevent sudden sound due to collision. In addition, as a material of the buffer member 82, the same material as the buffer members 28 and 29 of FIG. 2 can be used.
[0072]
<Ninth embodiment>
FIG. 10 is a side view of the recording sheet conveyance direction switching mechanism according to the ninth embodiment. This switching mechanism is obtained by omitting the deformable member in the third passage 43 from the configuration of FIG. For this reason, the same code | symbol is attached | subjected to the part similar to FIG. 5, and the description is abbreviate | omitted.
[0073]
The switching mechanism of FIG. 9 is obtained by fixing a deformable member 71 in a substantially linear shape along the first guide portion 34 of the first passage 41 by an adhesive portion 71b of the first guide portion 34 by bonding. The deformable member 71 passes through the outlet vicinity portion 34a of the first guide portion 34 toward the outlet 10 so as to form a gap 72 with the first guide portion 34, and the distal end portion 71a is discharged. It extends to the vicinity of the roller pair 9. The leading end st of the recording sheet conveyed through the third passage 43 comes into contact with the deformable member 71 in the vicinity of the leading end 71a in the vicinity of the outlet 10, and the deformable member 71 is elastically deformed while the recording sheet is in the nip portion. 9a or rubber roller 9c is naturally introduced. Further, the leading end portion st of the recording sheet does not collide with the exit vicinity portion 34a of the first guide portion 34. Thereby, the same effect as FIG. 5 can be acquired.
[0074]
Note that the deformable members 61, 62, 63 described above can be configured integrally with the switching guide 21. In this case, the material constituting the switching guide 21 is preferably ABS resin, vinyl chloride, polyacetal, polycarbonate, fluorine-based resin, polyimide, polyamideimide, or acrylic resin.
[0075]
In addition, the recording sheet conveyance direction switching mechanism according to the first to ninth embodiments can be applied to a portion other than the area A in FIG. 1, and an apparatus that conveys a sheet-like member other than the image forming apparatus. Can also be used.
[0076]
【The invention's effect】
According to the present invention, it is possible to provide a sheet-like member conveyance direction switching mechanism capable of preventing sudden sound generated when the conveyance direction of the sheet-like member is switched by the switching guide, and an image forming apparatus such as a copying machine or a printer. The noise can be reduced.
[0077]
Further, it is possible to provide a sheet-like member conveyance direction switching mechanism capable of preventing sudden sound generation caused by the collision of the sheet-like member that occurs when the sheet-like member is reversed and discharged. Can be achieved.
[Brief description of the drawings]
FIG. 1 is a schematic side view of an electrophotographic image forming apparatus to which a sheet-like member conveyance direction switching mechanism according to the present invention can be applied.
FIG. 2 is a side view of the recording sheet conveyance direction switching mechanism according to the first embodiment of the present invention.
FIG. 3 is a side view of a recording sheet conveyance direction switching mechanism according to a second embodiment of the present invention.
FIG. 4 is a side view of a recording sheet conveyance direction switching mechanism according to a third embodiment of the present invention.
FIG. 5 is a side view of a recording sheet conveyance direction switching mechanism according to a fourth embodiment of the present invention.
FIG. 6 is a side view of a recording sheet conveyance direction switching mechanism according to a fifth embodiment of the present invention.
FIG. 7 is a side view of a recording sheet conveyance direction switching mechanism according to a sixth embodiment of the present invention.
FIG. 8 is a side view of a recording sheet conveyance direction switching mechanism according to a seventh embodiment of the present invention.
FIG. 9 is a side view of a recording sheet conveyance direction switching mechanism according to an eighth embodiment of the present invention.
FIG. 10 is a side view of a recording sheet conveyance direction switching mechanism according to a ninth embodiment of the present invention.
FIG. 11A is a side view of a conventional recording sheet conveyance direction switching mechanism, and FIG. 11B is a side view for explaining recording sheet conveyance in the switching mechanism.
[Explanation of symbols]
1 Photosensitive drum
2 Fixing device
9 Discharge roller pair
9a Nip part
10 Exit
11 Fixing roller pair
12 Reverse roller pair
21 Switching guide
22 Rotating shaft
24 First side of switching guide
25 Second side of switching guide
26 Third aspect of switching guide
28, 29, 45 Buffer member
51, 52 cushioning member
34 1st guide part
34a Exit vicinity of first guide part
35 Second guide section
36 Third guide section
37, 38 Stopper
41 First passage
42 Second passage
43 Third passage
61, 62, 63 Deformable member (first deformable member)
61a, 62a Curve
62b Straight section
63a Tip of deformable member
71 Deformable member (second deformable member)
71a Tip of deformable member
81, 82 cushioning member
s Recording sheet (sheet-like member)
st The leading edge of the recording sheet

Claims (20)

A first passage through which the sheet-shaped member is conveyed;
A second passage that passes when the sheet-like member is conveyed in a direction different from the first passage;
A switching guide that switches the conveying direction of the sheet-like member between the first passage and the second passage by rotating to open one of the first and second passages;
A stopper portion that is provided in opposition to the switching guide, and that contacts the switching guide when the switching guide is rotated to switch the transport direction;
A sheet-like member conveyance direction switching mechanism comprising: a buffer member provided between the switching guide and the stopper portion. The sheet-like member conveyance direction switching mechanism according to claim 1, wherein the buffer member is provided in the switching guide. The sheet-like member conveyance direction switching mechanism according to claim 1 or 2, wherein the buffer member is provided in the stopper portion. 4. The sheet-like member conveyance direction switching mechanism according to claim 1, wherein the buffer member is made of foamable EPDM, thermoplastic elastomer, thermoplastic resin, silicon gel, or rubber. A first passage that passes when the sheet-like member is conveyed to the outlet;
A second passage that passes when the sheet-like member is conveyed in a direction different from the first passage;
A third passage configured to be able to pass when the sheet-like member that has passed through the second passage is transported toward the outlet by changing its transport direction;
The first, second, and third guide surfaces that define the first, second, and third passages, respectively, and rotate to open one of the first and second passages. A switching guide for switching the conveying direction of the sheet-like member between the first passage and the second passage,
A guide portion defining the first passage together with a first guide surface of the switching guide;
And a first deformable member projecting from the third guide surface of the switching guide in the third passage toward the outlet. The sheet-like member conveyance direction switching mechanism according to claim 5, wherein the projecting portion of the first deformable member includes a curved portion that is curved so that the sheet-like member faces the outlet. The sheet-like member conveyance direction switching mechanism according to claim 6, wherein the curved portion of the first deformable member has an arc shape with a radius of approximately 3 mm to 100 mm. The sheet-like member conveyance direction switching mechanism according to claim 6 or 7, wherein the projecting portion of the first deformable member includes a linear portion on a distal end side of the curved portion. The sheet-like shape according to claim 5, 6, 7, or 8, wherein the third guide surface of the third passage has a concave curved shape, and the first deformable member projects along the curved shape. Member transport direction switching mechanism. A discharge roller pair for further conveying and discharging the sheet-like member that has exited from the outlet is provided in the vicinity of the outlet, and the first deformable member extends to the vicinity of the discharge roller pair. 9. The sheet-like member transport direction switching mechanism according to any one of 9 above. 11. The sheet-like member conveyance direction switching mechanism according to claim 10, wherein the discharge roller pair includes a rubber roller and a resin roller, and the first deformable member extends to the vicinity of the rubber roller. . The sheet-like member conveyance direction switching mechanism according to claim 5, wherein the first deformable member is configured integrally with the switching guide. A second deformable member is further provided along the guide portion of the first passage, and a distal end portion of the second deformable member extends to the vicinity of the distal end portion of the first deformable member. The sheet-like member conveyance direction switching mechanism according to any one of 5 to 12. The sheet-like member conveyance direction switching mechanism according to claim 13, wherein a buffer member is provided between the guide portion of the first passage and the second deformable member. The sheet-like member conveyance direction switching mechanism according to claim 5, wherein a buffer member is provided between the third guide surface of the switching guide and the first deformable member. The first and second deformable members are polyethylene terephthalate having a thickness in the range of 30 μm to 350 μm, a stretched film of hard vinyl chloride, stretched polystyrene, soft polyethylene, or a stretched polypropylene film. The sheet-like member conveyance direction switching mechanism according to any one of the above. A first passage that passes when the sheet-like member is conveyed to the outlet;
A second passage that passes when the sheet-like member is conveyed in a direction different from the first passage;
A third passage configured to be able to pass when the sheet-like member that has passed through the second passage is transported toward the outlet by changing its transport direction;
The first, second, and third guide surfaces that define the first, second, and third passages, respectively, and rotate to open one of the first and second passages. A switching guide for switching the conveying direction of the sheet-like member between the first passage and the second passage,
A guide portion defining the first passage together with a first guide surface of the switching guide;
A sheet-like member conveyance direction switching mechanism comprising: a deformable member provided along the guide portion of the first passage and protruding toward the outlet. A pair of discharge rollers for further conveying and discharging the sheet-like member that has exited from the outlet is provided in the vicinity of the outlet, and the deformation is performed so that the sheet-like member that has passed through the third passage is guided to the discharge roller. The sheet-like member conveyance direction switching mechanism according to claim 17, wherein the possible member extends to the vicinity of the discharge roller pair. A pair of reversing rollers is provided in a direction extending toward the conveyance side of the second path, and the sheet-like member that has passed through the second path is conveyed toward the third path by the pair of reversing rollers and is turned from the outlet to the front and back. The sheet-like member conveyance direction switching mechanism according to claim 5, wherein the sheet is converted and discharged. An image forming apparatus comprising the sheet-like member conveyance direction switching mechanism according to claim 1.

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