JP2005035688A - Sheet transport device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet transport device to form a loop during the sheet transportation capable of reducing the impact sound generated during the sheet transportation. <P>SOLUTION: The sheet transport device is to transport the sheet using a first transporting means and to perform sheet transportation using a second transporting means after a loop is formed in the sheet by abutting the sheet leading edge to the second transporting means. The arrangement includes a first guide member having a projection part to assist the transport of the sheet having passed the first transporting means and a second guide member, and after a preliminary loop is formed in the sheet by the projection part on the first guide member and the second guide member, a bend of the sheet and its forefront position are corrected by abutting the sheet leading edge to the second transporting means for formation of the loop in the sheet. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sheet conveying device and an image forming apparatus having the sheet conveying device. More specifically, the sheet is abutted against a second conveying means (registration roller) and a loop is formed to thereby prevent the sheet from being bent or leading edge position. The present invention relates to a sheet conveying apparatus that performs correction and conveys, and an image forming apparatus using the sheet conveying apparatus.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been a sheet conveying unit used in an image forming apparatus or the like that performs an operation of forming a loop on a sheet being conveyed to correct the bending or leading edge position of the sheet. (For example, refer to Patent Document 1 and Patent Document 2).
[0003]
Here, an example of a conventional sheet conveying apparatus will be described with reference to FIG. FIG. 7 is a cross-sectional view showing a configuration of a conventional sheet conveying apparatus. First, the sheet P is gripped and conveyed by the roller 91 (first conveying means) and passes between the guide member 92 and the guide member 93. When the leading end portion Pa of the sheet P hits the registration roller 94 (second conveying means), the sheet P is greatly curved to form a loop as shown by the dotted line in the drawing. Thereafter, the conveyance of the roller 91 is temporarily stopped to form a large loop, thereby correcting the bending of the sheet and the leading end position of the sheet. The sheet P subjected to these corrections has a structure that is conveyed to the image forming unit in a timely manner.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 6-24588
[Patent Document 2]
JP-A-8-217291
[Problems to be solved by the invention]
However, in the conventional sheet conveying apparatus, when the sheet P is conveyed to the registration roller 94 and the sheet is in a substantially flat state and the leading end of the sheet collides with the registration roller, the sheet is not easily elastically deformed. In response to this, a loop is suddenly formed to absorb kinetic energy, so that the leading edge of the sheet strongly collides with the registration roller, and a large impact sound is generated when the leading edge of the sheet hits the registration roller. It was.
[0007]
The present invention has been made in view of the above problems. That is, an object of the present invention is to provide a sheet conveying apparatus capable of reducing an impact sound generated during sheet conveyance in a sheet conveying apparatus that forms a loop during sheet conveyance.
[0008]
Another object of the present invention is to reduce the impact noise generated during sheet conveyance as described above, and to temporarily cancel the impact noise reduction mechanism if necessary. For example, a sheet fed in a cassette It is another object of the present invention to provide a sheet conveying apparatus capable of smoothly conveying a manually fed sheet. Another object of the present invention is to provide an image forming apparatus in which the sheet conveying apparatus of the present invention is used in a sheet conveying path for feeding an image forming unit.
[0009]
[Means for Solving the Problems]
The inventor has analyzed the cause of a large impact sound when the leading end of the sheet comes into contact with the registration roller in the sheet conveying apparatus. As a result, it has been found that a large impact sound is generated when the sheet is conveyed in a straight state and hits the registration roller. This is because the sheet is transported in a straight state and collides with the registration rollers, and as a result of elastically deforming, the kinetic energy is forcibly absorbed and a loop is formed abruptly. It was speculated that the kinetic energy that did not exist became an impact sound.
[0010]
Based on such knowledge and assumption, the inventor of the present invention predicted and attempted to eliminate the generation of impact sound by allowing the sheet to efficiently form a loop, and as a result, It is what I found. That is, said subject is achieved by the following structure.
[0011]
(1) The sheet is conveyed by the first conveying means, the leading end of the sheet is abutted against the second conveying means to form a loop on the sheet, and then the sheet is conveyed by the second conveying means. In the sheet conveying apparatus, the sheet conveying apparatus includes a first guide member having a protruding portion for assisting conveyance of the sheet that has passed through the first conveying means, and a second guide member, and the protruding portion of the first guide member and the second guiding member. After the preliminary loop is formed on the sheet by the guide member, the leading end of the sheet is abutted against the second conveying unit to form the loop on the sheet, thereby correcting the bending and the leading end position of the sheet. A sheet conveying apparatus characterized in that the sheet is conveyed.
[0012]
In addition, the present inventor further frequently changes the sheet conveyance direction in a short time so that a manual sheet conveyance is performed immediately after conveying a sheet supplied from a paper feeding cassette in a recent image forming apparatus. Also, if necessary, the transport device capable of temporarily releasing the operation of the impact sound reducing means so that the means for reducing the impact sound does not interfere with different transport systems. As a result, the following structure was found. That is,
(2) The sheet is conveyed by the first conveying unit, the leading end of the sheet is abutted against the second conveying unit to form a loop on the sheet, and then the sheet is conveyed by the second conveying unit. In the sheet conveying apparatus, a first guide member having a movable protruding portion that assists conveyance of the sheet that has passed through the first conveying means, a second guide member, and the protruding portion of the first guide member are conveyed. A projecting portion retracting means for retracting to the opposite side to the second guide member with respect to the direction line, and when the projecting portion is not retracted by the projecting portion retracting means, the projecting portion of the first guide member After the preliminary loop is formed on the sheet by the second guide member, the leading end of the sheet is abutted against the second conveying unit to form the loop on the sheet, and the bending and the leading end position of the sheet are corrected. go Performs conveyance of over bets, when the projecting portion is retracted to the projecting portion retracting means, the sheet conveying device and performs the conveyance of the sheet is not formed a preliminary loop to the seat.
[0013]
(3) An image forming apparatus, wherein the sheet conveying apparatus according to (1) or (2) is formed in a conveying path of a sheet to be fed to an image forming unit in the image forming apparatus.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
(Embodiment 1)
A sheet conveying apparatus according to Embodiment 1 and an image forming apparatus to which the sheet conveying apparatus is applied will be described. FIG. 1 is a sectional view of a configuration of an image forming apparatus to which a sheet conveying apparatus is applied. An image forming apparatus 1 shown in FIG. 1 is a digital image forming apparatus, and includes an image reading unit A, an image processing unit B, an image forming unit IS, and a recording material conveying unit D as a recording material conveying unit. Yes.
[0015]
An automatic document feeder that automatically conveys the document is provided above the image reading unit A. The document placed on the document table 11 is separated and conveyed by the document conveyance roller 12 to the reading position 13a. The image is read. The document after the document reading is completed is discharged onto the document discharge tray 14 by the document transport roller 12.
[0016]
On the other hand, the image of the original when placed on the platen glass 13 is read at a speed v of the first mirror unit 15 including the illumination lamp and the first mirror constituting the scanning optical system, and the V-shaped first image is located. Reading is performed by the movement of the second mirror unit 16 including the two mirrors and the third mirror in the same direction at the speed v / 2.
[0017]
The read image is formed on the light receiving surface of the image sensor CCD, which is a line sensor, through the projection lens 17. The line-shaped optical image formed on the image sensor CCD is sequentially photoelectrically converted into an electrical signal (luminance signal) and then A / D converted, and the image processing unit B performs processing such as density conversion and filter processing. Then, the image data is temporarily stored in the memory.
[0018]
In the image forming unit IS, as an image forming unit, a drum-shaped photoconductor 21 as an image carrier, a charging means 22 for charging the photoconductor 21 on the outer periphery thereof, and a potential for detecting the surface potential of the charged photoconductor. A detecting means 220, a developing means 23, a transfer pole 24 and a separating pole 25 as transfer separating means, a cleaning device 26 for the photosensitive member 21, and a PCL (precharge lamp) 27 as a light discharging means are arranged in the order of operation. . Further, on the downstream side of the developing means 23, a reflection density detecting means 222 for measuring the reflection density of the patch image developed on the photosensitive member 21 is provided. The photoconductor 21 is formed by coating a photoconductive compound on a drum base. For example, an organic photoconductor (OPC) is preferably used and is driven to rotate in the clockwise direction shown in the drawing.
[0019]
After the rotating photosensitive member 21 is uniformly charged by the charging unit 22, image exposure based on an image signal called from the memory of the image processing unit B is performed by an exposure optical system 30 as an image exposure unit. An exposure optical system 30 serving as an image exposure means serving as a writing means uses a laser diode (not shown) as a light source, passes through a rotating polygon mirror 31, an fθ lens 34, and a cylindrical lens 35, and the optical path is bent by a reflection mirror 32 to perform main scanning. Therefore, image exposure is performed on the photoconductor 21 at the position Ao, and a latent image is formed by rotation (sub-scanning) of the photoconductor 21. In one example of the present embodiment, the character portion is exposed to form a latent image.
[0020]
The latent image on the photoreceptor 21 is subjected to reversal development by the developing unit 23, and a visible toner image is formed on the surface of the photoreceptor 21. In the recording material conveyance section D, paper feeding units 41 (A), 41 (B), and 41 (C) are provided below the image forming unit as recording material storage means for storing sheets P of different sizes. A manual paper feed unit 42 that performs manual paper feed is provided on the side, and the sheet P selected from any of these is fed along the first transport path (1) by the guide roller 43, and further, The sheet P passes through the first conveying unit 71 and is temporarily stopped by a registration roller which is the second conveying unit 76. During this time, the correction of the bending of the sheet P and the correction of the leading end position are performed, which will be described in detail later. The sheet P is temporarily stopped and then re-feeded. The sheet P is guided by the first transport path {circle around (1)}, the pre-transfer roller 43a, the paper feed path 46 and the entry guide plate 47, and the toner image on the photosensitive member 21 is transferred. The sheet P is transferred onto the sheet P by the transfer electrode 24 and the separation electrode 25 at the transfer position Bo, and is separated from the surface of the photoreceptor 21 while being placed and conveyed on the conveying belt 454 of the conveying belt device 45, and the conveying belt device 45. Thus, the toner is conveyed to an induction heating type fixing device 50 as fixing means.
[0021]
The fixing device 50 includes a heating roller 51 as a heating member and a pressure roller 53 as a pressure member, and the sheet P is heated by passing between the fixing roller 51 and the pressure roller 53. The toner is fixed by pressurization. The sheet P on which the toner image has been fixed is discharged onto the paper discharge tray 64.
[0022]
The above describes the state in which image formation is performed on one side of the sheet P. In the case of double-sided copying, the sheet discharge switching member 170 is switched, the sheet guide unit 177 is opened, and the sheet P as a sheet is indicated by a dashed arrow. It is conveyed in the direction of.
[0023]
Further, the sheet P is conveyed downward by the conveyance mechanism 178 and switched back by the sheet reversing unit 179, and is conveyed into the duplex copying paper supply unit 130 with the rear end of the sheet P as a sheet as the leading end.
[0024]
The sheet P moves the conveyance guide 131 provided in the duplex copying sheet feeding unit 130 in the sheet feeding direction, the sheet P is fed again by the sheet feeding roller 132, and the sheet P is guided to the first conveyance path (1). To do. Again, as described above, the sheet P is conveyed in the direction of the photosensitive member 21, the toner image is transferred to the back surface of the sheet P, fixed by the fixing device 50, and then discharged onto the discharge tray 64.
[0025]
Here, the sheet conveying apparatus will be described in detail. 2 is a cross-sectional view illustrating the configuration of the sheet conveying apparatus according to the first embodiment, FIG. 3 is a perspective view illustrating the first guide member according to the first embodiment, and FIG. 4 is a diagram illustrating a sheet conveying locus in the sheet conveying apparatus. It is.
[0026]
As shown in FIGS. 2, 3, and 4, the first guide member 72 has a protruding portion that assists the conveyance of the sheet that has passed through the first conveyance means 71. Specifically, the first guide member 72 has a protruding portion 72a that is a protruding portion with respect to the conveying direction line W in the sheet contacting portion 71a of the roller that is the first conveying means 71 with which the sheet P abuts. The surface of the projecting portion 72a serves to bend the sheet P conveyed by the first conveying means 71 from the leading end. As shown in FIG. 3, the first guide member 72 forms a plurality of convex-shaped portions 721a that protrude and are adjacent to the guide portion 72b on the surface. Next, the 2nd guide member 74 is provided facing the 1st guide member 72, and the said protrusion part which protruded with respect to the conveyance direction line has a convex-shaped part seeing from the direction orthogonal to a sheet conveyance direction. The second guide member 74 has a guide portion 74a, and bends the sheet in a direction opposite to the bending direction in which the front end of the sheet P is bent on the surface of the protruding portion 72a.
[0027]
The control means performs the preliminary loop La in advance by the protrusion 72a of the first guide member 72 and the second guide member 74 immediately before the leading end Pa of the sheet P hits the stopped second conveying means 76. After being formed and abutted against the resist roller which is the second conveying means 76 that is stopped, the final large loop Lb (see FIG. 4D) is formed from the preliminary loop La (see FIG. 4C). So that it is controlled.
[0028]
(Description of operation)
Here, the operation of the sheet conveying apparatus will be described with reference to the drawings. FIG. 4 is a diagram illustrating a sheet conveyance locus. The sheet P is conveyed by the first conveying means 71, and the leading end portion Pa of the sheet P has a convex portion 721a in a protruding portion 72a that is a portion protruding with respect to the conveying direction line W (FIG. 2). When the leading end Pa hits this part, P bends from the leading end Pa (FIG. 4A). The sheet P is further conveyed, and then the leading end portion Pa of the sheet P hits the second guide member 74 (FIG. 4B). The sheet P is then conveyed in a reverse direction while forming a preliminary curl (FIG. 4C). The leading end pa of the sheet P is further fed and stops against the registration roller as the second conveying means 76, and then the sheet P becomes a large loop Lb to correct the bending of the sheet P, correct the leading end position, The conveyance of one conveyance means 71 is temporarily stopped. At this time, a repulsive force acts on the sheet P from the second conveying means 76. However, since the sheet P has already formed the preliminary curl La, when the sheet P collides, the preliminary curl portion is elastically deformed and the impact is absorbed. The impact sound is reduced (FIG. 4 (d)). Thereafter, the sheet P is sent to the image forming unit in a timely manner (FIG. 4E).
[0029]
As described above, the leading edge of the sheet collides with the registration roller, but since the sheet is already curved and forms a preliminary loop, the sheet moves elastically from the preliminary loop to the final loop with a weak force. Since the energy is absorbed, the leading edge of the sheet collides lightly with the registration roller and there is little impact sound. On the other hand, as in the past, when the sheet is almost flat and the leading edge of the sheet collides with the registration roller, the sheet receives a large force from the parallel direction of the planar shape, which is difficult to elastically deform, and forms a loop suddenly and moves. Since energy is to be absorbed, it is presumed that the leading edge of the sheet strongly collides with the registration roller and generates a large impact sound.
[0030]
(Embodiment 2)
A sheet conveying apparatus according to the second embodiment and an image forming apparatus to which the sheet conveying apparatus is applied will be described with reference to the drawings. Parts that are mechanically the same as those in the first embodiment are given the same reference numerals, and parts of the parts that are mechanically the same are not described.
[0031]
FIG. 5 is a cross-sectional view showing the configuration of the sheet conveying apparatus when the first conveying path (normal) is used, and FIG. 6 is a cross-sectional view showing the configuration of the sheet conveying apparatus when using the second conveying path (manual feed). FIG.
[0032]
As shown in FIGS. 5 and 6, the sheet conveying apparatus has a first conveying path (1) and a second conveying path (2), and the first conveying path (1) is for at least one paper feed stage. The second conveyance path (2) is a conveyance path for manual feeding.
[0033]
The first guide member 73 has a protruding portion that assists the conveyance of the sheet that has passed through the first conveyance means 71. Specifically, the first guide member 73 has a protruding portion 84a that is a protruding portion with respect to the conveyance direction line W in the sheet contact portion 71a of the roller that is the first conveying means 71 with which the sheet P abuts. Yes. The surface of the projecting portion 84a functions to bend the sheet P conveyed by the first conveying means 71 from the leading end. In the second embodiment, the protruding portion 84a is provided with a retractable convex portion 841a. The surface of the first guide member 73 is a guide portion 73b.
[0034]
Next, a second guide member 75 is provided to face the first guide member 73, and the second guide member 75 has a guide portion 75a and a bending direction in which the front end of the sheet P is bent on the surface of the protruding portion 84a. Bends the sheet P in the opposite direction.
[0035]
The control means performs the preliminary loop La in advance by the projecting portion 84a of the first guide member 73 and the second guide member 75 until immediately before the leading end portion Pa of the sheet P hits the stopped second conveying means 76. After being formed and abutted against the resist roller which is the second conveying means 76 that is stopped, the final large loop Lb (see FIG. 4D) is formed from the preliminary loop La (see FIG. 4C). So that it is controlled.
[0036]
Further, the protruding portion retracting means 80 is a means that enables the protruding portion 84 a of the first guide member 73 to be retracted to the opposite side of the second guide member 75 with respect to the transport direction line W. In the protruding portion retracting operation, when the motor 81 first rotates counterclockwise in FIG. 5, the pin 83 formed on the first lever 82 fixed to the motor shaft rotates in the same counterclockwise direction. Then, the pin 83 pushes the long groove of the second lever 84 to rotate the second lever 84 counterclockwise, and the protrusion 84a formed on the second lever 84 moves from the solid line position to the dotted line position in FIG. . In addition, the protrusion operation | movement of a protrusion part is performed by said reverse process.
[0037]
(Description of operation)
In the operation of the sheet conveying apparatus when the first conveying path (1) is used, the protruding portion 84a is first brought into the protruding state. In this state, the sheet P is conveyed by the first conveying means 71. When the leading end portion Pa of the sheet P hits the protruding portion 84a, the sheet P is bent from the leading end portion P, and the sheet P is further conveyed, and then the sheet P The front end portion Pa of the second portion contacts the second guide member 75. The sheet P is conveyed while forming the preliminary curl La, and the leading end portion pa of the sheet P hits a registration roller as the second conveying means 76 and stops. When the sheet P hits, a repulsive force acts on the sheet P. However, since the sheet P has already formed the preliminary curl La, the sheet P is elastically deformed when the sheet P is deformed to absorb the impact and reduce the impact sound. Thereafter, the sheet P becomes the maximum loop Lb, corrects the bent tip position of the sheet, and the conveyance of the first conveying means 71 is temporarily stopped. Thereafter, the sheet P is sent to the image forming unit with timing. As described above, it is possible to reduce the impact sound when the sheet collides with the second conveying unit 76.
[0038]
Next, in the operation of the sheet conveying apparatus when using the second conveying path (2), the protruding portion 84a is first retracted by the protruding portion retracting means 80. The sheet P is conveyed from a manual sheet feeding unit (not shown) and conveyed by a conveyance roller as the third conveyance unit 77, and the leading end portion Pa of the sheet P is further conveyed without hitting the protruding portion 84a. Pa hits the registration roller which is the second conveying means 76 and stops. Thereafter, the sheet P becomes a loop to correct the position of the bent end of the sheet, and the conveyance of the first conveying means 71 is temporarily stopped. Thereafter, the sheet P is sent to the image forming unit with timing.
[0039]
In particular, in order to prioritize sheet conveyance, only the first conveyance path {circle over (1)} is used, but the operation when the protruding portion 84a is retracted will be described. First, the protrusion 84 a is retracted by the protrusion retracting means 80. The sheet P is conveyed, is conveyed by the first conveying means 71, and the leading end portion Pa of the sheet P is further conveyed without hitting the protruding portion 84a, and the leading end portion pa of the sheet P is the second conveying means 76. Stops hitting the roller. Thereafter, the sheet P becomes a loop to correct the position of the bent end of the sheet, and the conveyance of the first conveying means 71 is temporarily stopped. Thereafter, the sheet P is sent to the image forming unit with timing.
[0040]
In this embodiment, the sheet conveying apparatus that conveys a sheet to the image forming unit in the image forming apparatus has been described. However, the present invention can also be applied to a sheet conveying apparatus that feeds a document (sheet) in a document reading unit in the image forming apparatus. Nor.
[0041]
【The invention's effect】
Since it comprised as mentioned above, there exist the following effects.
[0042]
According to the first aspect of the present invention, the first guide member includes a first guide member having a protruding portion for assisting conveyance of the sheet that has passed through the first conveyance unit, and a second guide member. After the preliminary loop is formed on the sheet by the protrusion and the second guide member, the leading end of the sheet is abutted against the second conveying means to form the loop on the sheet, and the bending of the sheet and the leading end Since the position is corrected, it is possible to reduce the impact sound generated during sheet conveyance in the sheet conveyance apparatus that forms a loop during sheet conveyance.
[0043]
According to the second aspect of the present invention, the first guide member having the protruding portion for assisting the conveyance of the sheet that has passed through the first conveying means, the second guide member, and the protruding portion of the first guide member are conveyed. Protruding portion retracting means that can be retracted on the opposite side to the second guide member with respect to the direction line, and when the projecting portion is not retracted, by the projecting portion of the first guide member and the second guide member, After the preliminary loop is formed on the sheet, the leading end of the sheet is abutted against the second conveying means, and the loop is formed on the sheet to correct the bending and the leading end position of the sheet, while the protruding portion is retracted. In this case, since the preliminary loop is not formed, the impact noise of the sheet caused by the contact of the sheet with the second conveying means (registration roller) is reduced, and in particular, the sheet conveying property is given priority. If you want to I was able to retreat. Further, when there are a plurality of conveying paths, for example, in some cases, the protruding portion may cause trouble in sheet conveyance, the protruding portion can be retracted.
[0044]
According to the third aspect of the present invention, the first transport path for transporting the sheet and the second transport path for the sheet are formed, and the first transport path is used without retracting the protrusion, When using the second conveyance path, the projecting part is retracted, so that the impact noise of the sheet is reduced on one side and the conveyance of the sheet can be reliably performed on the other side. .
[0045]
According to the invention described in claim 4, the first conveyance path is a conveyance path for at least a sheet feeding stage that normally feeds sheets, and the second conveyance path is a conveyance path for manual sheet feeding. Therefore, the sheet conveying apparatus can be applied to an image forming apparatus having the sheet feeding stage and the manual sheet feeding unit.
[0046]
According to the fifth aspect of the present invention, since the protruding portion protruding with respect to the conveyance direction line has a convex shape portion when viewed from a direction orthogonal to the sheet conveyance direction, the convex shape portion bends the sheet. It is possible to perform smoothly, and to reduce the sliding resistance that the sheet receives from the first guide member when the sheet is conveyed by the second conveying means.
[0047]
According to the sixth aspect of the present invention, since the first guide member is provided with the plurality of protrusions adjacent to the direction orthogonal to the sheet conveyance direction, the sheet can be bent and conveyed with less frictional resistance at the protrusions. It became possible to carry out smoothly.
[0048]
According to the seventh aspect of the present invention, since the sheet conveying apparatus of the present invention is used in the conveying path of the sheet fed into the image forming unit in the image forming apparatus, the impact caused by the sheet hitting the second conveying means. The sound can be reduced.
[Brief description of the drawings]
FIG. 1 is a sectional view of a configuration of an image forming apparatus to which a sheet conveying device is applied.
FIG. 2 is a cross-sectional view illustrating a configuration of a sheet conveying apparatus according to a first embodiment.
3 is a perspective view illustrating a first guide member according to Embodiment 1, and FIG. 4 is a diagram illustrating a sheet conveyance locus in the sheet conveyance apparatus.
FIG. 4 is a diagram illustrating a sheet conveyance locus in the sheet conveyance apparatus.
FIG. 5 is a cross-sectional view illustrating a configuration of a first conveyance path (normal) of a sheet conveyance apparatus according to a second embodiment.
FIG. 6 is a cross-sectional view illustrating a configuration of a second transport path (manual feed) of the sheet transport apparatus according to the second embodiment.
FIG. 7 is a cross-sectional view illustrating a configuration of a conventional sheet conveying apparatus.
[Explanation of symbols]
71 1st conveyance means 72, 73 1st guide members 72a, 84a Protrusion part 72b, 73b Guide part 721a, 841a Convex-shaped part 74, 75 2nd guide member 76 2nd conveyance means 80 Protrusion part retracting means

Claims (7)

A sheet conveying apparatus that conveys a sheet by the second conveying unit after conveying the sheet by the first conveying unit, butting the leading end of the sheet against the second conveying unit to form a loop on the sheet In
A first guide member having a protrusion for assisting conveyance of the sheet that has passed through the first conveyance means, and a second guide member,
By forming the preliminary loop on the sheet by the protruding portion of the first guide member and the second guide member, the sheet leading end is abutted against the second conveying means, and the loop is formed on the sheet. A sheet conveying apparatus, wherein the sheet is conveyed by correcting the bending and leading edge position of the sheet. A sheet conveying apparatus that conveys a sheet by the second conveying unit after conveying the sheet by the first conveying unit, butting the leading end of the sheet against the second conveying unit to form a loop on the sheet In
A first guide member having a movable protrusion for assisting conveyance of the sheet that has passed through the first conveyance means; a second guide member; and the protrusion of the first guide member with respect to a conveyance direction line. A protrusion retracting means for retracting to the opposite side to the second guide member;
When the protrusion is not retracted by the protrusion retracting means, a preliminary loop is formed on the sheet by the protrusion of the first guide member and the second guide member, and then the sheet leading end is Abutting on the conveying means, forming a loop on the sheet, correcting the bending and leading edge position of the sheet, conveying the sheet,
A sheet conveying apparatus that conveys a sheet without forming a preliminary loop on the sheet when the protruding portion is retracted by the protruding portion retracting means. When the first conveyance path and the second conveyance path for conveying the sheet are formed, and the first conveyance path is used, the protruding portion is used without being retracted, and when the second conveyance path is used. The sheet conveying apparatus according to claim 2, wherein the protruding portion is retracted and used. The first conveyance path is a conveyance path for at least one sheet feeding stage that normally feeds at least a sheet, and the second conveyance path is a conveyance path for manual sheet feeding. Item 4. The sheet conveying apparatus according to Item 3. 5. The sheet conveying apparatus according to claim 1, wherein the protruding portion protruding with respect to the conveying direction line has a convex portion when viewed from a direction orthogonal to the sheet conveying direction. 6. The sheet conveying apparatus according to claim 1, wherein the first guide member is provided with a plurality of the protruding portions adjacent to each other in a direction orthogonal to the sheet conveying direction. 7. An image forming apparatus comprising: the sheet conveying apparatus according to claim 1 formed on a conveyance path of a sheet fed to an image forming unit in the image forming apparatus.

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