JPH07315622A - Paper sheet carrier for image forming device - Google Patents

Abstract

PURPOSE:To prevent the loop of a paper sheet from beating a guide plate and the occurrence of noise in a state where the loop is formed in the paper sheet between carry roller devices being different in speed. CONSTITUTION:In order to check the strongly pressing action of the loop of a paper sheet against a lower guide plate in a state where carry roller devices 43, 55 being different in carrying speed are arranged in upstream and downstream sections to a connection part between a carry passage 40 for a double- face tray member and the form carry passage 20 of a device body, a curved guide section 60 is arranged to a curved passage. In the curved guide section 60, two oscillating guide plates 62, 65 are combined, and a sheet 61 is provided on their upper faces, and when the loop of the paper sheet is formed, the oscillating guide plates 62, 65 are set up so that they may be oscillated in a direction where they can escape from pressure caused by the loop. Thus the loop of the paper sheet can be prevented from strongly beating the oscillating guide plate for preventing the occurrence of noise.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper guide means at a connecting portion between a paper feed path from a paper feed tray of a paper feed section of an image forming apparatus and a paper guide path for conveying a paper toward an image recording section. In particular, the present invention relates to a sheet conveying device of an image forming apparatus that can favorably guide the sheet even when the sheet is strongly pressed against a guide plate outside the curved portion of the sheet conveying path.

[0002]

2. Description of the Related Art In an image forming apparatus such as an electrophotographic copying machine, a plurality of paper feed trays and other paper accommodating means are arranged in a paper feed section, and papers of different sizes and paper qualities are placed in those paper feed trays. It is configured so that it can be accommodated and any paper can be sent out in accordance with the size of the original. As a device capable of mounting a plurality of paper feed trays as described above, for example, a device shown in Japanese Patent Laid-Open No. 5-323719 is known, and the image forming apparatus of the conventional example is shown in FIG. It is configured as shown in. FIG. 7
The electronic copying machine as the image forming apparatus 1 shown in 1 is provided with a mechanism for writing an image using a digital method, and is configured as an automatic double-sided copying machine.

In the image forming section arranged above the main body of the image forming apparatus, the image information output from the image signal output device 6 is output from the writing device 7 to the photosensitive drum 2 as an image carrier. A mechanism for forming a toner image by using an electrophotographic system is constituted by scanning with a laser beam for scanning. Around the photosensitive drum 2, as in a general electronic copying machine, a charger, a developing device 3,
A transfer / peeling corotron 4, a cleaning device 5, etc. are arranged. After charging the photosensitive drum, an image is written to form an electrostatic latent image, and toner is supplied from the developing device to visualize the electrostatic latent image and transfer it to a sheet. A means for cleaning the toner and the like remaining on the surface of the photoconductor drum after the image transfer is cleaned by a cleaning device.

An aligning portion 30 is provided at an end portion of the sheet conveying path 20 at an upstream portion of a transfer portion of the toner image from the photosensitive drum 2.
And a plurality of paper feed trays 10 to 13 and a double-sided tray member 1 with respect to the paper transport path 20 upstream of the aligning unit.
The paper feed path from 4 is connected. Paper feed devices 15 to 19 are arranged in each of the paper feed trays and the double-sided tray member, and the paper accommodated in each tray is sent out by using each paper feed device, and inside the paper transport path 20. In, the carrying action is performed while being nipped by the plurality of carrying roller devices. Then, the sheet conveyed in the sheet conveying path 20 is temporarily stopped at the aligning section 30, and is sent to the image transfer section in time with the toner image formed on the photosensitive drum, and then is transferred to the photosensitive drum. The formed toner image is transferred.

The sheet on which the toner image has been transferred from the photoconductor drum 2 is introduced into the fixing device 9 via the conveying device 21 and fixed there, and then discharged onto the discharging tray 2 via the discharging roller 23.
Discharge to 4. In the image forming apparatus, a return path 25 is connected in the middle of the discharge path via the switching gate 22, and a mechanism for sending the single-sided copy paper toward the double-sided tray member 14 via the return path 25 is provided. When the copy mode set in the image forming apparatus is set to the multiple copy creation mode, the single-sided copy sheet is guided from the return path 25 to the double-sided tray member 14 through the switching gate 26. Then, the single-sided copy sheet is accommodated in the double-sided tray member with the image side thereof facing downward so that another image is transferred onto the image side of the single-sided copy sheet in the next copying operation.

In the return path 25, the double-sided tray member 14
A switching gate 26 and a reversing path 27 below the switching gate 26 are arranged at a position corresponding to the above, and when the electronic copying machine is set to the double-sided copy mode, a sheet for one-sided copying is returned from the return path 25. It is fed toward the inversion path 27. Then, the forward / reverse driving roller device 28 provided in the reversing path 27 is reversely driven to feed the single-sided copy sheet to the double-sided tray member 14 through below the switching gate 26,
Store the paper in the inverted state. Therefore, the reversed single-sided copy sheet has the image surface facing upward in the double-sided tray member 14, and the toner image is transferred to the back surface of the single-sided copy sheet sent from the double-sided tray member. You can make double-sided copies.

A side door member 35 that can be opened and closed is provided via a hinge 36 on the side surface of the apparatus main body corresponding to the return path and the reverse path on the side of the discharge tray. When a jam occurs in the transport path for transporting the single-sided copy sheet, the side door member is opened so that the jam sheet can be easily processed. further,
Corresponding to the paper transport path from the paper feed tray, an openable cover member (not shown) is also installed on the other side of the main body of the device to perform operations such as paper jam processing in the paper transport path. It's easy to do.

[0008]

In the image forming apparatus having the above-mentioned structure, the sheet conveying speeds are often different between the sheet conveying paths, and the sheet is conveyed between the conveying roller apparatuses having different conveying speeds. A slack or extra tension may be applied to the paper during transportation. For example, as shown in FIG.
When the sheet is guided from 7 to the conveying path 40 of the double-sided tray member, the speed of the forward / reverse driving roller device 28 arranged in the reversing path 27 is high, whereas the conveying path 40 of the double-sided tray member is high. In the delivery roller device 43 arranged in
It is set to a relatively low speed. In addition, with the conventional example shown below,
In the embodiment of the present invention, the paper feed section and the paper feed section of the double-sided tray member from each device, and the paper transport path 2 of the main body of the device.
An example will be described in which the feeding path is directly connected without arranging the paper feeding unit at the connecting portion with 0.

In the above-mentioned conventional example, as compared with the transport speed of the delivery roller device 43 arranged in the delivery portion of the transport path 40, the transport roller device 55 provided in the paper feed path 40.
In, the transport speed is set to a relatively low speed. Therefore, the transport path 40 for the double-sided tray member 14 as described above.
On the other hand, the slack of the paper occurs in the curved path 50 at the portion for feeding the paper and the portion for sending the paper toward the transport path. Then, there occurs a problem that the slack portion of the paper strongly slides on the guide plate forming the curved path, and noise is generated when the paper hits the guide plate.

The curved path 50 shown in FIG. 8 has a structure as shown in FIG. 9, for example, and is arranged at the downstream side of the conveying path 40 of the double-sided tray member.
3 is configured as shown in FIG. In the example shown in FIG. 9, the curved path 50 arranged between the conveyance path 40 of the double-sided tray member and the sheet conveyance path 20 of the apparatus body is constituted by guide plates 51 and 52 that guide the front and back surfaces of the sheet. Then
The sheet can be guided toward the sheet conveying path 20.
Further, as shown in FIG. 10, a delivery roller device 43 for delivering the paper from the transport path 40 to the curved path 50 is composed of a drive roller member and a pinch roller member 48, and a drive shaft 45 of the drive roller member. , Are provided with a plurality of rollers 45a, 45b, ... At predetermined intervals, and rollers 48a, 48b, ... Of pinch roller members are provided corresponding to the rollers 45a, 45b.

A pulley 46 is arranged at the end of the drive shaft 45 of the drive roller member, and the drive force is transmitted by the drive belt 47. Further, the roller of the pinch roller member is attached via a means for supporting and biasing a leaf spring or the like so that the pinch roller member can perform a pressing action on the drive roller member. In the delivery roller device 43 configured as described above, a corrugation state in the width direction is set between the rollers with respect to the paper P, and the paper P is directed toward the transport roller device 55 in the downstream portion while strengthening the stiffness of the paper. The paper is prevented from buckling inside the curved path 50 by being sent out.

However, as shown in FIGS. 9 and 10, even when the corrugation is formed on the sheet conveyed in the curved path, if the curved path is formed with a very small radius, There is a problem that the corrugation in the width direction of the paper is crushed and an abnormal noise is generated. Then, the paper sent out by the sending roller device 43 from the conveying path of the double-sided tray member strongly slides on the guide plate below the curved path when a loop is formed on the curved path, or the paper is not formed when the loop is formed. The problem of hitting the guide plate hard remains. Therefore, in order to solve the above-mentioned problems, for example, as shown in Japanese Utility Model Laid-Open No. 61-181046, a guide plate arranged on a curved sheet conveying path is swung in accordance with a loop of sheets. It is also conceivable to make it possible. However, as shown in FIG. 7, it is not possible to arrange a mechanism for greatly swinging the guide plate in a narrow place, such as a connection portion between a sheet feeding path such as a sheet feeding tray and the sheet conveying path of the main body. It is very difficult, and under the present circumstances, there is a demand for the development of a device that can well guide the paper on a curved path and prevent the generation of abnormal noise.

[0013]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the conventional sheet conveying apparatus, and when a loop is formed on the sheet between two roller devices having different conveying speeds, the sheet is not transferred. With the purpose of providing a device that can prevent the loop from strongly hitting the guide plate, etc.,
Further, it is an object of the present invention to provide a sheet conveyance device capable of canceling the influence of a loop by canceling the nip of the sheet at the upstream conveyance roller device when the fed-out sheet is nipped by the low-speed conveyance roller device. I am trying.

[0014]

SUMMARY OF THE INVENTION According to the present invention, a paper feed path having a paper feed path disposed on both sides of the paper feed path is provided from a paper storage means such as a plurality of paper feed trays, and the plurality of paper feed paths. And a guide path for guiding the paper toward the image recording unit. In the present invention, the sheet guiding means is constituted by a movable chute member capable of swinging in correspondence with a portion on the outer side of the curved portion of the sheet conveying path, and with respect to the sheet sliding surface of the movable chute member, A sheet-shaped guide member having one end fixed to the guide plate is arranged. Further, in the present invention, the transport roller devices are arranged close to the upstream and downstream portions of the curved portion of the paper transport path, and the nip of the paper can be released in the transport roller device at the upstream part in the paper transport direction. A mechanism is provided, and a sheet detecting means is arranged in the vicinity of the transport roller device in the downstream portion, and means for releasing the nip action of the sheet in the transport roller device in the upstream portion is provided based on the detection information from the sheet detecting means. ing.

[0015]

In the sheet conveying device of the image forming apparatus of the present invention constructed as described above, the connecting portion between the upstream conveying path and the sheet conveying path of the apparatus main body is formed as a curved path, and the outside of the curved path. The swingable guide plate is arranged with respect to the guide plate and the plastic sheet member is arranged on the inner surface of the swingable guide plate. When a loop is formed on the sheet conveyed in the curved path, the sheet loop slides along the sheet member while pressing and swinging the swing guide plate. It is possible to prevent hitting hard. Further, the rocking guide plate for guiding the sheet automatically returns to the original position when the pressing action of the sheet is released, so that the guiding action for the sheet can be performed in a good state. In addition to the above configuration, in the transport roller device arranged on the curved path of the present invention, the upstream transport roller device is used as a delivery roller device, and a mechanism for releasing the nip is arranged with respect to the delivery roller device. The nip of the upstream delivery roller device can be released in the state where the paper is nipped and transported by the transport roller device on the transport path. Therefore, when the sheet is conveyed between the two conveying paths, the conveying action on the sheet by one of the conveying roller devices is interrupted, so that the loop of the sheet does not strongly hit the guide plate and the noise of the sheet is reduced. Occurrence can be prevented.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A sheet conveying device of an image forming apparatus of the present invention will be described with reference to the illustrated example. The example shown in FIG. 1 shows, for example, a case where a unit for feeding the paper fed from the double-sided tray member toward the paper transport path of the apparatus main body is configured as shown in FIG. ,
A curved guide portion 60 is arranged, for example, at a connection portion with the double-sided tray member 14 with respect to the sheet conveyance path 20 of the apparatus main body. The arrangement of the upper guide plate 51 in the curved guide portion 60 is the same as in the case of the conventional device, but two swing guide plates 62, 65 are provided in combination in place of the lower guide plate. Further, in the conveying roller device arranged in the upstream and downstream portions of the curved path, the sending roller device 43 on the conveying path 40 side conveys the paper at high speed, and the conveying roller device 55 arranged in the paper conveying path 20 has a relatively low speed. It is configured to perform the paper transport operation. Then, in the curved path, a loop is automatically formed on the sheet when the sheet is conveyed by the conveying roller device at the upstream and downstream portions.

As shown in FIG. 2, the two rocking guide plates have a comb tooth portion 63 arranged at the tip of the plate member main body supported by the support shaft 64 so as to be rockable. The spring 68 urges the swing guide plate 62 clockwise. The swing guide plate 65 combined with the swing guide plate 62 is provided with comb teeth at the end of the plate member, is swingably supported via a support shaft 67, and is supported by a spring 69 with respect to the shaft. It is installed so that it is biased counterclockwise. Then, the two rocking guide plates 62,
65 is configured to be slidable relative to each other by combining concave and convex portions arranged at the leading end portion thereof, and configured to be able to guide the bending of the sheet.

As described above, the two rocking guide plates 62 and 65 are combined with each other through the comb teeth, and a plastic sheet 61 is formed on the surface which constitutes the paper guide surface.
And the tip of the upstream portion of the seat 61 is attached to the surface of the swing guide plate 65 via an adhesive portion 61a. Then, when the sheet passes through the curved guide portion,
When the sheet 61 slides on the sheet, it acts as a guide,
When a loop is formed on the paper, apply a pressing force of 2 to the loop.
Make sure that the two rocking guide plates are received. Therefore, as shown in FIG. 1, as the sheet loop becomes larger, the swing guide plates 62 and 65 are swung through their respective support shafts, so that the sheet pressure can be released. To In addition, when a sheet loop is formed on the curved guide portion, the loop gradually becomes larger as the sheet is conveyed, so that the swing guide plate is swung by the pressure of the loop. By the movement, the loop portion of the paper does not suddenly hit the swing guide plate.

In the example shown in FIG. 1, the transport path 40 is configured to be connected to the end of the paper transport path 20 of the main body of the apparatus. It is also possible to configure a means for guiding the paper by connecting the transport path with. In the example shown in FIG. 3, a curved guide path from the conveyance path 40 is connected to a part in the middle of the paper conveyance path 20, and one upper guide plate 5 of the paper conveyance path 20 is connected.
1 is bent and connected to the upper guide plate of the conveyance path 40, and the curved guide portion 60 is provided with a guide means that is a combination of two swing guide plates 62 and 65 and a sheet 61. The curving guide portion 60 allows the sheet conveyed from the lower portion of the sheet conveying path to pass through the confluence portion of the curved path,
For the paper sent out from the transport path 40, a means for guiding the paper to the paper transport path via the curved guide portion 60 of the curved path is configured.

When a loop occurs in the sheet due to the difference in the sheet conveying speed between the feed roller device 43 arranged on the conveying path 40 and the conveying roller device 55 on the sheet conveying path, the sheet is not transferred. By pressing the rocking guide plates 62 and 65 via 61 and rocking the rocking guide plates via the support shaft, the pressing force of the loop of the sheet can be released. Further, as in the case of FIG. 2, a biasing means by a spring is arranged for the two rocking guide plates to prevent the loop of the sheet from being strongly hit by the curved guide portion. Therefore, it is possible to prevent an abnormal noise from being generated in the course of the paper feeding operation. Even in the apparatus shown in FIG. 3, the leading edge of the sheet is prevented from being caught by the comb-like portion of the swing guide plate due to the sheet sliding on the sheet.

[0021]

[Second Embodiment] In addition to the above-described paper guiding means, in the present invention, the carrying roller device arranged on a curved path causes the carrying operation of the paper to be carried by the carrying roller device at the downstream portion. By this, it is possible to configure a conveying means that does not form an extra loop. In the example shown in FIG. 4, as in the example shown in FIG. 3, the curved path 50 from the conveyance path of the double-sided tray member is connected to the sheet conveyance path 20 of the apparatus main body, Curved road 5
0 is a delivery roller device 70 having a high transport speed in the upstream portion.
The downstream transport roller device 55 is configured as a low speed roller. Further, sensors S and S1 for detecting a sheet are respectively arranged at the end of the conveying path and a position of the sheet conveying path near the conveying roller device, and information on the sheet obtained by the sensor is used. Means for controlling the sheet nip in the delivery roller device 70 is provided. Further, a swinging guide plate 65 is arranged via a support shaft 67 at a portion corresponding to the lower guide plate of the curved path 50, and a sheet 61 is arranged on the surface of the swinging guide plate so that a sheet 61 can be fed to the sheet. It constitutes a means for providing guidance. In the present invention, the swing guide plate 65 and the seat 61 may be provided and the lower guide plate may be arranged in a fixed state.

In the example shown in FIG. 4, the sending roller device 70 arranged at the end of the conveying path 40 is constructed by combining a driving roller member 71 and a pinch roller member 75, and nips a sheet between both rollers. In this state, the transport operation is performed. The pinch roller member 75
Then, the roller is supported by a member such as a leaf spring 76, and the leaf spring 76 is provided on the support shaft 77, and the support shaft 77 is swung to separate the pinch roller member 75 from the drive roller member. Performs the action of contact. Further, when the rear arm 78 is arranged with respect to the support shaft 77 and the stopper 79 is provided corresponding to the rear arm, the support shaft 77 is swung to separate the pinch roller member 75 from the drive roller member 71. In addition, means for restricting the swing range of the support shaft is configured.

In order to swing the pinch roller member of the delivery roller device 70, for example, a device as shown in FIG. 5 can be constructed. In the example shown in FIG. 5, the drive transmission device 80 is arranged on the drive shaft 72 of the drive roller member, and is driven by the drive means (not shown) via the drive belt 81 to the drive pulley provided on the drive shaft. The force is transmitted to drive the driving roller member. Further, a gear device 83 is arranged between the drive shaft 72 and the support shaft 77 of the pinch roller member, and constitutes a means for transmitting the rotation of the drive shaft 72 for driving the drive roller member to the support shaft 77. . Further, the support shaft 77 is provided with an electromagnetic clutch 85 and torque control means 86 such as a torque limiter, and the support shaft 77 is rotated counterclockwise in FIG. 4 only when the electromagnetic clutch 85 is connected. Constitutes a means. Torque control means 86 is provided on the support shaft 77.
Since the rear arm 78 is locked to the stopper 79, the torque control means 86 slides to separate the pinch roller member from the drive roller member without further rotating the support shaft. To be able to hold in the state.

When the nip releasing means of FIG. 5 is provided for the delivery roller device 70 as shown in FIG. 4, the leading end of the sheet passes through the delivery roller device,
When detected by the sensor S provided on the conveyance roller device of the sheet conveyance path, the electromagnetic clutch is connected according to the detection information of the sensor S, and the support shaft 77 of the pinch roller member rotates. Then, when the rear arm 78 is swung until it comes into contact with the stopper 79, the torque control means 86 slides, so that the rotation of the support shaft 77 is stopped and the state in which the nip of the delivery roller device 70 is released is maintained. The action of transporting the sheet is performed only by the downstream transport roller device 55.

The carrying action for the paper is performed as shown in the timing chart of FIG.
After the sensor S1 arranged in the conveyance path detects the sheet and the sensor S arranged in the sheet conveyance path detects the leading edge of the sheet, the control device outputs a command to energize the electromagnetic clutch and the electromagnetic clutch is connected. By doing so, the spindle is rotated. Then, the sensor S1 at the upstream portion outputs information that the rear end portion of the sheet is detected, so that the power supply to the electromagnetic clutch is stopped, the swinging operation with respect to the spindle is interrupted, and the pinch roller member of the feed roller device is stopped. Is pressed against the drive roller member.

Therefore, by disposing the conveying roller device and the sending roller device as shown in FIG. 4, it is possible to eliminate the condition that the sheet is conveyed on the curved path by the two conveying roller devices at different speeds. It is possible to perform control so that a large loop is not formed on the paper. Therefore, when the means for controlling the nip with respect to the transport roller device is provided, it is possible to prevent noise from being generated due to the loop of the paper strongly hitting the lower guide plate. As the sheet to be arranged on the curved path of the present invention, for example, a thin film such as polyethylene terephthalate or another plastic film-shaped member can be used. When the film member is used, the sheet conveyed in the ascending direction in the sheet conveying path with the tip portion thereof protruding into the sheet conveying path can pass in the state of pushing the film member away. It does not hinder the paper transported in the transport path.

Further, the swing guide plate arranged on the curved path can be made of a relatively lightweight plastic material, and if it is one that swings easily when pressed by the paper, The swing guide plate can be easily swung by the pressing force of the loop of the sheet. In the embodiment of the present invention, the rocking guide plate is arranged on the curved path for guiding the sheet from the double-sided tray member to the sheet conveying path, and the nip in the conveying roller device is released. Although the case has been described, as the curved road of the present invention,
It can be arranged at an arbitrary position of a curved portion of a sheet conveying path of an image forming apparatus or a connecting portion at a right angle. It can also be applied to the connection part of the return path.

[0028]

Since the sheet conveying device of the image forming apparatus of the present invention is constructed as described above, the connecting portion between the upstream conveying path and the sheet conveying path of the apparatus body is constructed as a curved path. In this case, a swingable swinging guide plate is arranged on the guide plate outside the curved path, and a plastic sheet is arranged on the inner surface of the swinging guide plate to guide the sheet. Means can be provided. When a loop is formed on the sheet conveyed in the curved path, the sheet loop slides along the sheet while pressing and swinging the swing guide plate. It is possible to prevent the player from hitting hard and prevent abnormal noises from being generated. Further, the rocking guide plate for guiding the sheet automatically returns to the original position when the pressing action of the sheet is released, so that the guiding action for the sheet can be performed in a good state.

In addition to the effects described above, in the carrying roller device arranged on the curved path of the present invention, a mechanism for releasing the nip can be arranged with respect to the carrying roller device at the upstream portion. Then, the nip of the delivery roller device in the upstream portion can be released in a state where the paper is nipped and conveyed by the conveyance roller device of the paper conveyance path of the apparatus main body, so that the paper is conveyed between the two conveyance paths. In doing so, it is possible to exert the action of interrupting the action of transporting the sheet by one of the transport roller devices. Therefore, by performing the sheet conveying operation without forming a large loop on the sheet, the loop of the sheet does not strongly hit the guide plate, and it is possible to prevent noise from being generated.

[Brief description of drawings]

FIG. 1 is a side view showing the configuration of a sheet conveying device according to the present invention.

FIG. 2 is a perspective view of a rocking guide plate arranged in a bending guide portion.

FIG. 3 is an explanatory diagram of another embodiment of the present invention.

FIG. 4 is an explanatory diagram of another embodiment of the present invention.

5 is an explanatory view of a nip releasing means provided in the apparatus of FIG.

6 is a timing chart showing the operation of releasing the nip in the apparatus of FIG.

FIG. 7 is an explanatory diagram showing a configuration of a general image forming apparatus.

FIG. 8 is an explanatory diagram showing a configuration of a conveyance path for a double-sided tray member.

FIG. 9 is an explanatory diagram of a curved path of a conventional paper transport path.

FIG. 10 is an explanatory diagram showing a configuration of a conventional delivery roller device.

[Explanation of symbols]

1 image forming apparatus, 14 double-sided tray member, 2
0 paper transport path, 40 transport path, 43 delivery roller device, 48 pinch roller member, 50
Curved road, 55 conveyance roller device, 60 curving guide part, 61 sheet, 62/65 swing guide plate, 70 delivery roller device, 80 drive transmission device, 85 electromagnetic clutch, 86 torque control means.

Claims (2)

[Claims] 1. A paper feed path comprising a guide plate disposed on both sides of the paper feed path, the paper feed path for feeding from a paper accommodating means such as a plurality of paper feed trays, and the plurality of paper feed paths are connected to each other, and an image recording unit In a sheet conveying path formed of a guide path for guiding the sheet toward, the sheet guiding means is constituted by a swingable movable chute member corresponding to the portion outside the curved portion of the sheet conveying path, A sheet conveying device of an image forming apparatus, wherein a sheet-shaped guide member having one end fixed to a guide plate is arranged on a sheet sliding surface of the movable chute member. 2. A conveyance roller device is arranged close to the upstream and downstream portions of a curved portion of the paper conveyance path, and a mechanism capable of releasing the nip of the paper is provided in the conveyance roller device at an upstream portion in the paper conveyance direction. In addition to being provided, the sheet detecting means is arranged in the vicinity of the downstream conveying roller device, and the nip action of the sheet in the upstream conveying roller device is released based on the detection information from the sheet detecting means. The sheet conveying device of the image forming apparatus according to claim 1.