JP6910796B2 - Sheet transfer device and image forming device - Google Patents

Description

The present invention relates to a sheet transporting device for transporting sheets and an image forming apparatus including the same.

Conventionally, in an image forming apparatus such as a printer, an image forming apparatus including a switching member for switching a transfer destination of a sheet that has passed through a fixing apparatus for fixing a toner image on the sheet has been proposed (see Patent Document 1). In this image forming apparatus, a sheet is guided to a discharge path or a return path by a switching member, and these discharge paths and return paths are formed to be curved for miniaturization of the device. A strong sheet such as cardboard exerts a force to straighten it by its own strength when passing through a curved discharge path and a return path. Therefore, when the rear end of the sheet is passed from the switching member to the discharge path or the return path, the sheet hits the discharge path or the return path, and an impact sound is generated.

Therefore, a printer has been proposed in which a plurality of elastic members are arranged side by side in the width direction of the sheet at a branch point of a transport path, and the elastic forces of the plurality of elastic members are made different (see Patent Document 2). Due to these plurality of elastic members having different elastic forces, the rear end of the sheet is bent in the width direction, and the impact sound when the rear end of the sheet and the transport path come into contact with each other can be dispersed.

Japanese Unexamined Patent Publication No. 03-279157 JP-A-2007-106551

However, the plurality of elastic members described in Patent Document 2 are fixed to one of the two confluent transport paths. Therefore, when the sheet is transported on the other side of the two transport paths, the sheet presses in the direction of peeling off the plurality of elastic members. As a result, if a plurality of elastic members are fixed with, for example, double-sided tape, the plurality of elastic members may be peeled off and the sheet may be jammed.

Therefore, an object of the present invention is to provide a sheet transfer device and an image forming device that solve the above-mentioned problems by reducing the impact noise when the sheet and the transfer path come into contact with each other while preventing the sheet from jamming. ..

According to the present invention, in a sheet transport device, a transport means for transporting a sheet, a first transport path and a second transport path for guiding the sheet transported by the transport means, and a first surface and a second surface for guiding the sheet. The sheet transport direction is between a first position for guiding the sheet to the first transport path by the first surface and a second position for guiding the sheet to the second transport path by the second surface. It is rotatably supported around an axis extending in the width direction orthogonal to the above, and when the first surface comes into contact with the sheet conveyed by the conveying means, it rotates from the second position to the first position. It has a first guide member for guiding the seat, and a third position for guiding the seat to the first transport path by the third surface, and a second position by the fourth surface. The sheet is rotatably supported between the fourth position for guiding the sheet to the transport path and the axis extending in the width direction independently of the first guide member, and is transported by the transport means. A second guide member that rotates from the fourth position to the third position when the third surface comes into contact with the third surface, and is a central portion of a sheet transport region rather than the first guide member in the width direction. By abutting the second guide member arranged at a position close to the first guide member and the first guide member rotating from the second position toward the first position, the first guide member is moved to the first position. A second positioning unit that positions the second guide member at the third position by abutting against the first positioning portion for positioning and the second guide member that rotates from the fourth position toward the third position. The rotation amount of the second guide member, which is provided with a positioning portion and rotates from the fourth position to the third position, rotates from the second position to the first position. The first positioning portion and the second positioning portion are configured so as to be larger than the momentum, and the third surface of the second guide member located at the third position is located at the first position. It is characterized in that it is located at a position different from the first surface of the first guide member to be located when viewed from the width direction.
Further, in the sheet transport device, the present invention includes a transport means for transporting the sheet, a first transport path and a second transport path for guiding the sheet transported by the transport means, and a first surface and a first surface for guiding the sheet. The seat has two surfaces, a first position for guiding the sheet to the first transport path by the first surface, and a second position for guiding the sheet to the second transport path by the second surface. It is rotatably supported around an axis extending in the width direction orthogonal to the transport direction, and when the first surface comes into contact with the sheet transported by the transport means, the second position is directed toward the first position. It has a rotating first guide member, third and fourth surfaces for guiding the seat, and the third position for guiding the seat to the first transport path by the third surface, and the fourth surface for guiding the seat. It is rotatably supported between the fourth position for guiding the sheet to the second transport path and the axis extending in the width direction independently of the first guide member, and is transported by the transport means. A second guide member that rotates from the fourth position to the third position when the third surface comes into contact with the sheet, and is a transport region of the sheet rather than the first guide member in the width direction. By abutting the second guide member arranged at a position close to the central portion and the first guide member rotating from the second position toward the first position, the first guide member is brought into the first guide member. The second guide member is positioned at the third position by abutting against the first positioning portion for positioning at the position and the second guide member that rotates from the fourth position toward the third position. The first guide member is provided with two positioning portions, and the amount of rotation of the second guide member that rotates from the fourth position to the third position rotates from the second position to the first position. The first positioning portion and the second positioning portion are configured so as to be larger than the amount of rotation of the first guide member and the second guide member. The first transport path provided at a branching portion with the road has a first guide surface for delivering a sheet to the first surface of the first guide member and the third surface of the second guide member. The second transport path has a second guide surface through which a sheet is delivered from the first surface of the first guide member and the third surface of the second guide member, and the first guide member is the first surface. In the state where the second guide member is located at the first position and the second guide member is located at the third position, the first guide surface is in the sheet transport direction. The distance between the downstream end and the first surface of the first guide member is smaller than the distance between the downstream end of the first guide surface and the third surface of the second guide member, and The distance between the tip of the first guide member and the second guide surface is larger than the distance between the tip of the second guide member and the second guide surface.

According to the present invention, it is possible to reduce the impact noise when the seat and the transport path come into contact with each other while preventing the seat from jamming.

The whole schematic which shows the printer which concerns on 1st Embodiment. The perspective view which shows the 2nd guide unit. The perspective view which shows the 2nd guide unit. The cross-sectional view which shows the 2nd guide unit. The figure which shows the 2nd guide unit seen from the arrow D direction of FIG. The cross-sectional view which shows the difference of the rotation amount of a plurality of guide members. The cross-sectional view which shows the operation of the guide member arranged on the end side in the width direction. The cross-sectional view which shows the operation of the guide member arranged on the central side in the width direction. FIG. 5 is a cross-sectional view showing the operation of a plurality of guide members when the switched back sheet is conveyed. The perspective view which shows the plurality of guide members and holding members which concerns on 2nd Embodiment. The figure which shows a plurality of guide members which concerns on 3rd Embodiment.

The printer 100 according to this embodiment is an electrophotographic color laser beam printer. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in this embodiment are not intended to limit the scope of the present invention to those unless otherwise specified. .. Further, the sheet transfer device according to the present invention is not limited to a color laser beam printer, but is an inkjet image forming device that forms an image on a sheet by ejecting an ink liquid from a copying machine, a facsimile, or a nozzle. It may be applied.

<First Embodiment>
〔overall structure〕
First, the first embodiment of the present invention will be described. The printer 100 as an image forming apparatus is an electrophotographic laser beam printer, and as shown in FIG. 1, an image forming unit 10 for forming an image on a sheet S, a fixing device 18, a sheet discharging device 27, and the like. It has a sheet feeding device 24 and. The image forming unit 10 as an image forming means forms four process cartridges 3Y, 3M, 3C, which form a toner image of four colors of yellow (Y), magenta (M), cyan (C), and black (K), respectively. It includes 3K and a scanner unit 9.

The four process cartridges 3Y, 3M, 3C, and 3K have the same configuration except that the colors of the images to be formed are different. Only the configuration of the process cartridge 3Y and the image forming process will be described, and the process cartridges 3M, 3C, 3K, The description of 3K will be omitted.

The process cartridge 3Y includes a photosensitive drum 1Y, a charging roller 2Y, a developing unit 4Y having a developing roller 6Y, and a cleaning blade 8Y. The photosensitive drum 1Y is configured by applying an organic photoconductive layer on the outer circumference of an aluminum cylinder, and is rotated by a drive motor (not shown). Further, the image forming unit 10 is provided with an intermediate transfer belt 12 rotated by a drive roller 13, and the intermediate transfer belt 12 is pulled in the direction of arrow I by the tension roller 14. Primary transfer rollers 11Y, 11M, 11C, and 11K are provided inside the intermediate transfer belt 12.

The fixing device 18 includes a fixing film 19 that is heated by a heater 7 as a heating means, and a pressure roller 20 that press-contacts the fixing film 19. The sheet discharging device 27 as a sheet transporting device includes a first guide unit 30, a second guide unit 38 described later, a first discharging roller pair 21 and a second discharging roller pair 31 as a transporting means. ing. The sheet feeding device 24 is provided at the lower part of the printer 100, and includes a feeding cassette 23 for storing sheets and a pickup roller 24a for feeding out the sheets S loaded and stored in the feeding cassette 23.

Next, the image forming operation of the printer 100 configured in this way will be described. When an image signal is input to the scanner unit 9 from a personal computer or the like (not shown), the scanner unit 9 irradiates the photosensitive drum 1Y of the process cartridge 3Y with a laser beam corresponding to the image signal.

At this time, the surface of the photosensitive drum 1Y is uniformly charged to a predetermined polarity and potential in advance by the charging roller 2Y, and an electrostatic latent image is formed on the surface by irradiating the surface with laser light from the scanner unit 9. .. The electrostatic latent image formed on the photosensitive drum 1Y is developed by the developing roller 6Y, and a yellow (Y) toner image is formed on the photosensitive drum 1Y.

Similarly, the photosensitive drums 1M, 1C, and 1K of the process cartridges 3M, 3C, and 3K are also irradiated with laser light from the scanner unit 9, and the photosensitive drums are magenta (M), cyan (C), and black (K). Toner image is formed. The toner images of each color formed on each photosensitive drum are transferred to the intermediate transfer belt 12 by the primary transfer rollers 11Y, 11M, 11C, 11K, and up to the secondary transfer roller 16 by the intermediate transfer belt 12 rotated by the drive roller 13. Be transported.

The image forming process of each color is performed at the timing of superimposing on the upstream toner image primaryly transferred on the intermediate transfer belt 12. Further, after the toner images of each color are transferred to the intermediate transfer belt 12, the toner remaining on the surface of the photosensitive drums 1Y, 1M, 1C, 1K is removed by the cleaning blades 8Y, 8M, 8C, 8K.

In parallel with this image forming process, the sheet S housed in the feeding cassette 23 is fed by the pickup roller 24a and then transported to the registration roller pair 17. The skew is corrected by the registration roller pair 17, and intermediate transfer is performed on the first sheet surface (surface) of the sheet S conveyed at a predetermined transfer timing by the secondary transfer bias applied to the secondary transfer roller 16. The full-color toner image on the belt 12 is transferred. The residual toner remaining on the intermediate transfer belt 12 is recovered by the cleaner portion 26.

Predetermined heat and pressure are applied to the sheet S on which the toner image is transferred by the fixing film 19 and the pressure roller 20 of the fixing device 18, and the toner is melt-fixed (fixed). The sheet S that has passed through the fixing device 18 is guided to the first discharge transport path R1 by the first guide unit 30, and is discharged to the discharge tray 22 by the first discharge roller pair 21.

When an image is formed on both sides of the sheet S, the sheet S is guided to the second discharge transfer path R2 by the first guide unit 30, passes through the second guide unit 38, and is conveyed to the second discharge roller pair 31. .. The second guide unit 38 selectively guides the seat S to the second discharge transport path R2 and the double-sided transport path R3. When the rear end of the seat S passes through the second guide unit 38, the second discharge roller pair 31 rotates in the opposite direction, and the seat S is switched back and guided to the double-sided transport path R3. The sheet S is conveyed to the lower part of the printer 100 by the discharge roller pair 34 on the double-sided transfer path R3, and is guided to the registration roller pair 17 by the third guide unit 35. After that, an image is formed on the second sheet surface (back surface) of the sheet S, and the sheet S is discharged to the discharge tray 22 by the first discharge roller pair 21.

[Configuration of 2nd guide unit]
Next, the configuration of the second guide unit 38, which is the main part of the present invention, will be described. As shown in FIG. 2, the second guide unit 38 is rotatably supported by a holding member 39 having a first guide surface 41, a rotating shaft 40 held by the holding member 39, and a rotating shaft 40. It has a plurality of guide members 32 (14 in the present embodiment). The rotating shaft 40 is composed of an iron shaft that has been surface-treated, and penetrates through a plurality of guide members 32.

As shown in FIGS. 2 and 3, the plurality of guide members 32 are arranged side by side in the width direction (arrow Y direction in the figure) orthogonal to the sheet transport direction, and are independently centered on the rotation shaft 40. It is rotatably supported. The second guide unit 38 having the plurality of guide members 32 is configured symmetrically with respect to the central portion T in the width direction of the sheet transport region. The plurality of guide members 32 are each configured to have the same shape. Hereinafter, the first, fourth, and seventh guide portions from the central portion T toward the outside in the width direction are referred to as guide members 32a, 32b, and 32c, respectively, and the guide members 32a, 32b, and 32c are mainly used. Explain to. The axis 40a of the rotating shaft 40 extends in the width direction orthogonal to the sheet transport direction and the sheet thickness direction, but even if it extends in the inclined direction within ± 10 degrees with respect to the width direction. good.

As shown in FIG. 4, the guide members 32a, 32b, 32c guide the sheet S to the second discharge roller pair 31 with the first slopes 33a, 33b, 33c and the switchback-conveyed sheet S on the double-sided transport path R3. The second slopes 37a, 37b, and 37c, which are guided to the above, are provided, respectively. The first slopes 33c and 33a constitute the first surface and the second surface, respectively, and the second slopes 37c and 37a constitute the third surface and the fourth surface, respectively. Further, the guide members 32a, 32b, 32c rotate toward the second discharge transport path R2 due to their own weight, and by contacting, for example, a stopper (not shown), the guide members 32a, 32b, 32c stand by in a state of protruding into the second discharge transport path R2. There is. That is, the guide members 32a, 32b, 32c stand by at the same position when viewed from the width direction in a state where they are not pressed by the sheet to be conveyed.

Therefore, in a state where the guide members 32a, 32b, 32c abut on a stopper (not shown) and protrude into the second discharge transport path R2, the first slopes 33a, 33b, 33c are arranged so as to overlap each other when viewed from the width direction. ing. As a result, the tip of the sheet S to be conveyed abuts on the first slopes 33a, 33b, 33c at the same time, so that the sheet S can be reduced from skewing. The guide members 32a, 32b, and 32c are configured to be rotatable upward, that is, in the direction of the arrow K by being pressed by the sheet S conveyed by the fixing device 18.

As shown in FIGS. 5 and 6, the amount of rotation of the guide members 32a, 32b, 32c is defined by a plurality of abutting portions 42a, 42b, 42c formed on the holding member 39. As shown in FIG. 6, the guide member 32c as the first guide member arranged on the outermost side in the width direction from the central portion T has an abutting portion 42c as a first contact portion when pressed by the sheet S. By hitting against, it is configured to be rotatable by the first rotation amount V1. The guide member 32b, which is arranged inside the guide member 32c in the width direction, abuts against the abutting portion 42b when pressed against the seat S, so that only the third rotation amount V3, which is larger than the first rotation amount V1. It is configured to be rotatable. The guide member 32a as the second guide member closest to the central portion T abuts on the abutting portion 42a as the second abutting portion when pressed by the seat S, thereby causing the first rotation amount V1 and the third rotation. It is configured to be rotatable only by the second rotation amount V2, which is larger than the momentum V3. The state in which the guide members 32a, 32b, and 32c are not in contact with the sheet S is shown by a two-dot chain line in FIG.

Therefore, the guide members 32a and 32c are configured as follows. The guide member 32c has a first position (position shown in FIG. 6) for guiding the seat S to the second discharge transport path R2 by the first slope 33c, and a second position for guiding the seat S to the double-sided transport path R3 by the second slope 37c. It is rotatable between two positions (positions shown in FIG. 4). Then, the guide member 32c is positioned at the first position by abutting against the abutting portion 42c. The guide member 32a has a third position (position shown in FIG. 6) for guiding the seat S to the second discharge transport path R2 by the first slope 33a, and a second position for guiding the seat S to the double-sided transport path R3 by the second slope 37a. It is rotatable between four positions (positions shown in FIG. 4). Then, the guide member 32a is positioned at the third position by abutting against the abutting portion 42a.

In the above description, the three guide members 32a, 32b, and 32c have been particularly described, but the abutting portion is configured so that the other guide members among the plurality of guide members 32 have the same tendency. That is, the plurality of guide members 32 are provided so that the amount of rotation is symmetrically different with respect to the central portion T. More specifically, the plurality of guide members 32 are provided so that the amount of rotation gradually decreases from the central portion T toward the outside in the width direction. For example, as shown in FIG. 3, the guide members 32e, which have the same configuration as the guide members 32c and 32a, respectively, as the third guide member and the fourth guide member so as to be symmetrical with respect to the central portion T in the width direction. 32d is provided.

[Operation of multiple guide members]
Next, the operation of the plurality of guide members 32 will be described with reference to FIGS. 7 and 8. FIG. 7 is a cross-sectional view showing a guide member 32c near the end in the width direction in the transport region, and the state when the rear end of the sheet S passes through the first guide surface 41 is a dotted line, and the rear end of the sheet S is The state when the guide member 32c is pulled out is shown by a alternate long and short dash line. FIG. 8 is a cross-sectional view showing a guide member 32a near the central portion T, in which the state when the rear end of the seat S passes through the first guide surface 41 is a dotted line, and the rear end of the seat S is a guide member 32c. The state at the time of pulling out is indicated by a alternate long and short dash line.

Here, in the vicinity of the branch portion R23 of the second discharge transport path R2 and the double-sided transport path R3, the second discharge transport path R2 as the first transport path has the first guide surface 41 curved when viewed from the width direction and the first guide surface 41. It is composed of a first facing guide surface 46 facing the one guide surface 41. The first guide surface 41 forms a part of the second discharge transport path R2, and the seat S is delivered to the plurality of guide members 32. The double-sided transport path R3 as the second transport path is composed of a second guide surface 43 and a second opposed guide surface 47 formed on the holding member 39 and facing the second guide surface 43. The second guide surface 43 receives the sheet S from the plurality of guide members 32.

In the following, it is assumed that a sheet S having a large size in the width direction capable of pressing all of the plurality of guide members 32 is conveyed. The sheet S conveyed to the second discharge transfer path R2 by the fixing device 18 presses all of the plurality of guide members 32 by the tip of the sheet and the second surface of the sheet, and the plurality of guide members 32 are abutted portions. It abuts (for example, abutting portions 42a, 42b, 42c).

At this time, as shown in FIGS. 7 and 8, the distance 53 between the downstream end 41a of the first guide surface 41 in the sheet transport direction and the first slope 33c of the guide member 32c is downstream of the first guide surface 41. It is smaller than the distance 51 between the end 41a and the first slope 33a of the guide member 32a. Further, the distance 54 between the tip 63c of the guide member 32c and the second guide surface 43 is larger than the distance 52 between the tip 63a of the guide member 32a and the second guide surface 43.

As described above, the distance between the downstream end 41a of the first guide surface 41 and the plurality of guide members 32 is smaller in the outer guide member (for example, the guide member 32c) in the width direction, and the guide is closer to the central portion T. The larger the member (for example, the guide member 32a), the larger the size. Further, the distance between the tips of the plurality of guide members 32 and the second guide surface 43 is larger in the outer guide member (for example, the guide member 32c) in the width direction, and the guide member (for example, the guide) closer to the central portion T. The member 32a) becomes smaller.

Therefore, when the sheet S bends in the width direction when it comes into contact with the plurality of guide members 32, and the rear end of the sheet S exceeds the step between the first guide surface 41 and the plurality of guide members 32, the width is widened. The guide member on the outer side in the direction comes into contact with the guide member on the central side in order. Therefore, the impact sound when the rear end of the sheet S and the plurality of guide members 32 come into contact with each other can be dispersed, and the impact sound can be reduced. Further, since the end portion of the rear end of the seat S in the width direction is supported by the guide member 32c at an early stage, the impact at the central portion is utilized while utilizing the rigidity of the seat itself from the end portion to the central portion in the width direction. Sound can be reduced.

Similarly, when the rear end of the seat S exceeds the step between the plurality of guide members 32 and the second guide surface 43, the guide member on the central side in the width direction is in sequential contact with the outer guide member. go. Therefore, the impact sound when the rear end of the sheet S and the second guide surface 43 come into contact with each other can be dispersed, and the impact sound can be reduced. Further, since the central portion of the rear end of the seat S in the width direction is supported by the second guide surface 43 at an early stage, the rigidity of the seat itself from the central portion to the end portion in the width direction is utilized at the end portion. Impact noise can be reduced.

Then, as shown in FIG. 9, when the rear end of the seat S passes through the plurality of guide members 32, the plurality of guide members 32 rotate downward in the gravity direction W due to their own weight, and are in a standby state. After that, as described above, the seat S is switched back and conveyed by reversing the second discharge roller pair 31 and guided to the double-sided transfer path R3 by the plurality of guide members 32.

As described above, since the rear end of the sheet S comes into contact with the plurality of guide members 32 and the second guide surface 43 at different timings, the impact sound can be dispersed and reduced. Further, since the plurality of guide members 32 are independently and rotatably supported by the rotation shaft 40, the plurality of guide members 32 can be pressed regardless of which side of the rotation direction the plurality of guide members 32 are pressed. There is no risk of falling off the rotating shaft 40. Therefore, it is possible to prevent the seat S from being jammed by being caught by the plurality of guide members 32 that have fallen off.

Further, since the plurality of guide members 32 are provided so as to rotate symmetrically with respect to the central portion T so that the amount of rotation differs, the frictional resistance acting on the seat S by the plurality of guide members 32 becomes line-symmetrical at the central portion T, and the seat S becomes linear. Can be prevented from skewing.

Further, since the seat S is bent so as to be curved in the width direction by the plurality of guide members 32, the curl of the seat S can be corrected. In particular, in the present embodiment, the heater 7 of the fixing device 18 is arranged on the first seat surface side of the sheet, and the first slopes (for example, the first slopes 33a, 33b, 33c) of the plurality of guide members 32 are the first slopes of the sheet. It is possible to contact the second seat surface side opposite to the first seat surface. When the sheet S passes through the fixing device 18, a temperature difference occurs between the first sheet surface, which is the surface to be heated, and the second sheet surface opposite to the surface, so that the difference in elongation between the front and back surfaces of the sheet S occurs. Occurs. Therefore, the end portion of the sheet S is curled in the direction away from the heater 7, but in the present embodiment, the curl can be corrected by the plurality of guide members 32.

Further, the plurality of guide members 32 are formed of a hard resin such as polypropylene or polyacetal, and have good assembly workability. Further, the plurality of guide members 32 can stably guide the sheet S regardless of the rigidity of the sheet such as thick paper or thin paper. In particular, by setting the centers of gravity of the plurality of guide members 32 so that the plurality of guide members 32 can be rotated upward by the thin paper, it is possible to prevent the thin paper from hitting the plurality of guide members 32 and jamming. can.

<Second embodiment>
Next, a second embodiment of the present invention will be described. However, since the second embodiment only changes the support configuration of the plurality of guide members 32 of the first embodiment, the first embodiment is described. The configuration similar to that of the embodiment will be described by omitting the illustration or adding the same reference numerals to the drawings.

As shown in FIG. 10, the plurality of guide members 132 have shaft portions 36, 36 extending in the width direction, respectively. A plurality of bearing portions 44, 44 are integrally formed on the holding member 139 having the first guide surface 41, and the bearing portions 44, 44 are shaft portions 36, respectively of the plurality of guide members 132. The 36 is rotatably held.

For example, when the guide member 132c arranged on the outermost side in the width direction is attached to the holding member 139, the shaft portions 36, 36 are placed outside the bearing portions 44, 44 with the distance between the shaft portions 36, 36 widened. Plug in from. As a result, a plurality of guide members 132 can be easily attached to the holding member 139, and the iron rotating shaft 40 in the first embodiment can be reduced, so that the cost can be reduced.

<Third embodiment>
Next, a third embodiment of the present invention will be described. However, since the third embodiment only changes the divided configuration of the plurality of guide members 32 of the first embodiment, the first embodiment is described. The configuration similar to that of the embodiment will be described by omitting the illustration or adding the same reference numerals to the drawings.

As shown in FIG. 11, the plurality of guide members 232 include a guide member 232a as a second guide member arranged at the center in the width direction, and guide members 232b and 232b arranged outside the guide member 232a, respectively. have. Further, the plurality of guide members 232 have guide members 232c and 232c as first guide members arranged outside the guide members 232b and 232b, respectively.

These guide members 232a, 232b, 232c are arranged according to the size of the sheet to be conveyed. For example, the executive size seat S1 as the first size contacts only the guide member 232a to rotate the guide member 232a. The vertically oriented A4 and the letter-sized sheet S2 come into contact with the guide members 232a and 232b to rotate the guide members 232a and 232b. The lateral A4 as the second size and the letter-sized sheet S3 come into contact with the guide members 232a, 232b, 232c to rotate the guide members 232a, 232b, 232c. The laterally oriented A4 and the letter-sized sheet S3 are longer in the width direction than the executive-sized sheet S1.

The rotation amount of the guide members 232a, 232b, 232c is defined by a plurality of abutting portions formed on the holding member 239, as in the first embodiment, and the rotation amount of the guide member 232a is the rotation amount of the guide member 232b. It is larger than the amount of rotation. Further, the rotation amount of the guide member 232b is set to be larger than the rotation amount of the guide member 232c.

As described above, by making the rotation amounts of the guide members 232a, 232b, and 232c different according to the size of the usable sheet, it is possible to reduce the impact noise when the sheet and the plurality of guide members 232 come into contact with each other. can. Further, since the number of parts of the plurality of guide members 232 is smaller than that of the first embodiment, the cost can be reduced.

In any of the above-described embodiments, the plurality of guide members are configured to rotate by their own weight, but even if each of the plurality of guide members is urged by an urging member such as a torsion coil spring. good. As a result, there are no restrictions on the rotation directions of the plurality of guide members, and the degree of freedom in design can be improved. For example, the present invention may be applied to the first guide unit 30 and the third guide unit 35.

Further, in any of the above-described embodiments, the guide member on the center side of the plurality of guide members is configured to have a larger amount of rotation than the guide member on the outer side, but the present invention is not limited to this. That is, the guide member on the center side of the plurality of guide members may be configured to have a smaller amount of rotation than the guide member on the outer side. Further, the number of the plurality of guide members is not particularly limited.

10: Image forming means (image forming unit) / 7: Heating means (heater) / 27: Sheet transporting device (sheet discharging device) / 31: Transporting means (second discharge roller pair) / 32a, 232a: Second guide member (Guide member) / 32c, 232c: 1st guide member (guide member) / 32d: 4th guide member (guide member) / 32e: 3rd guide member (guide member) / 33a: 3rd surface (1st slope) / 33c: 1st surface (1st slope) / 36: Shaft / 37a: 4th surface (2nd slope) / 37c: 2nd surface (2nd slope) / 40: Rotating shaft / 40a: Axis line / 41 : 1st guide surface / 41a: Downstream end / 42a: 2nd contact portion (butting portion) / 42c: 1st contact portion (butting portion) / 43: 2nd guide surface / 51, 52, 53, 54: Distance / 63a, 63c: Tip / 100: Image forming apparatus (printer) / 139: Holding member / R2: First transport path (second discharge transport path) / R3: Second transport path (double-sided transport path) / R23: Branch part / S: Seat / T: Central part / V1, V2: Rotation amount

Claims (9)

Transport means for transporting sheets and
A first transport path and a second transport path for guiding the sheet transported by the transport means, and
It has a first surface and a second surface for guiding the sheet, and the first surface guides the sheet to the first transport path, and the second surface guides the sheet to the second transport path. The second surface is rotatably supported around an axis extending in the width direction orthogonal to the sheet transport direction between the second position and the second position, and the first surface comes into contact with the sheet transported by the transfer means. A first guide member that rotates from a position to the first position,
It has a third surface and a fourth surface for guiding the sheet, and the third surface guides the sheet to the first transport path, and the fourth surface guides the sheet to the second transport path. The third surface is rotatably supported between the fourth position and the axis extending in the width direction independently of the first guide member, and the third surface comes into contact with the sheet conveyed by the conveying means. As a result, the second guide member that rotates from the fourth position to the third position is arranged at a position closer to the central portion of the sheet transport region than the first guide member in the width direction. With the second guide member
A first positioning unit that positions the first guide member at the first position by abutting against the first guide member that rotates from the second position to the first position.
A second positioning portion for positioning the second guide member at the third position by abutting the second guide member that rotates from the fourth position to the third position is provided.
The amount of rotation of the second guide member that rotates from the fourth position to the third position is larger than the amount of rotation of the first guide member that rotates from the second position to the first position. , The first positioning unit and the second positioning unit are configured .
The third surface of the second guide member located at the third position is located at a position different from the first surface of the first guide member located at the first position when viewed from the width direction. ,
A sheet transfer device characterized by this. The third surface of the second guide member located at the fourth position is arranged so as to overlap the first surface of the first guide member located at the second position when viewed from the width direction.
The sheet transport device according to claim 1. A third guide member and a fourth guide member having the same configuration as the first guide member and the second guide member are provided so as to be symmetrical with respect to the central portion in the width direction.
The sheet transport device according to claim 1 or 2 , wherein the sheet transport device is characterized by the above. Transport means for transporting sheets and
A first transport path and a second transport path for guiding the sheet transported by the transport means, and
It has a first surface and a second surface for guiding the sheet, and the first surface guides the sheet to the first transport path, and the second surface guides the sheet to the second transport path. The second surface is rotatably supported around an axis extending in the width direction orthogonal to the sheet transport direction between the second position and the second position, and the first surface comes into contact with the sheet transported by the transfer means. A first guide member that rotates from a position to the first position,
It has a third surface and a fourth surface for guiding the sheet, and the third surface guides the sheet to the first transport path, and the fourth surface guides the sheet to the second transport path. The third surface is rotatably supported between the fourth position and the axis extending in the width direction independently of the first guide member, and the third surface comes into contact with the sheet conveyed by the conveying means. As a result, the second guide member that rotates from the fourth position to the third position is arranged at a position closer to the central portion of the sheet transport region than the first guide member in the width direction. With the second guide member
A first positioning unit that positions the first guide member at the first position by abutting against the first guide member that rotates from the second position to the first position.
A second positioning portion for positioning the second guide member at the third position by abutting the second guide member that rotates from the fourth position to the third position is provided.
The amount of rotation of the second guide member that rotates from the fourth position to the third position is larger than the amount of rotation of the first guide member that rotates from the second position to the first position. , The first positioning unit and the second positioning unit are configured.
The first guide member and the second guide member are provided at a branch portion between the first transport path and the second transport path.
The first transport path has a first guide surface for delivering a sheet to the first surface of the first guide member and the third surface of the second guide member.
The second transport path has a second guide surface through which a sheet is delivered from the first surface of the first guide member and the third surface of the second guide member.
In a state where the first guide member is located at the first position and the second guide member is located at the third position, the downstream end of the first guide surface in the sheet transport direction and the first guide member The distance between the first surface is smaller than the distance between the downstream end of the first guide surface and the third surface of the second guide member, and the distance between the tip of the first guide member and the first surface is said to be smaller. The distance between the second guide surface is larger than the distance between the tip of the second guide member and the second guide surface.
Features and to Resid over preparative conveying device that. The first guide surface is formed so as to be curved when viewed from the width direction.
The sheet transport device according to claim 4 , wherein the sheet transport device is characterized by this. It is provided upstream of the first guide member and the second guide member in the sheet transport direction, and is provided with a heating means for heating the sheet from the first sheet surface side of the sheet.
The first surface of the first guide member and the third surface of the second guide member can come into contact with the second seat surface side opposite to the first seat surface of the seat.
The sheet transport device according to any one of claims 1 to 5 , wherein the sheet transport device is characterized by this. A rotation shaft extending in the width direction and rotatably supporting the first guide member and the second guide member is provided.
The sheet transport device according to any one of claims 1 to 6 , wherein the sheet transport device is characterized by this. The first guide member and the second guide member each have a shaft portion extending in the width direction.
A holding member for rotatably holding the shaft portion of each of the first guide member and the second guide member is provided.
The sheet transport device according to any one of claims 1 to 7 , wherein the sheet transport device is characterized by this. The sheet transfer device according to any one of claims 1 to 8.
An image forming means for forming an image on a sheet is provided.
An image forming apparatus characterized in that.

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