JPH0543082A - Sheet carrying device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a jam even in large size sheets by installing a driving shaft, having carrying rollers on its intermediate part and both its sides, in one side of a sheet carrying path, and making energization force, to carrying rollers on an intermediate part driven side, larger than that to carrying rollers on both side driven sides. CONSTITUTION:An opening and closing door 25 is provided on a sheet carrying device 7 on a paper feeding deck, and on the other hand, a driving shaft 27 having carrying rollers 26, two on an intermediate part and one on each of both sides, is installed in a deck main body 5 side. Moreover driven side carrying rollers 33, carrying sheets in cooperation with driving side carrying rollers 26, are supported with a spring support shaft 34. At that time, the energization force of the spring support shaft 34 to two intermediate part driven side carrying rollers 33 is made stronger than that to both the side driven side carrying rollers 33, and the carrying force of the intermediate part carrying rollers 26 and 33 pair is made stronger than that of both the side rollers 26 and 33 pair. This enables the carrying force with four carrying roller pairs 26 and 33 to be equalized in a sheet width direction, displaying effectiveness for preventing jam occurrence.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrostatographic copying machine or a printer, and a sheet conveying apparatus mounted on a sorter or the like.

[0002]

2. Description of the Related Art As the above-mentioned sheet conveying device, as shown in FIG. 5, a drive shaft 42 having two conveying rollers 41 is installed on one side of the sheet conveying path and is conveyed to the other side of the sheet conveying path. A conveyance guide plate 43 is provided so as to be switchable to a road open state, and a driven side conveyance roller 44 that conveys a sheet with the driving side conveyance roller 41 is fixed at both ends and the driven side conveyance roller 44 is driven. It is known that a spring 45 for biasing and abutting the transport roller 41 on the side is provided on the transport guide plate 43 with a supporting shaft as a pivot.

[0003]

By the way, conventionally, the interval between the transport rollers 41 and 44 is made as wide as possible within the range in which small size sheets can be transported. There was a problem that feeding was unstable and jamming was likely to occur.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sheet conveying device which can stably convey a large size sheet without causing a jam.

[0005]

In the paper transporting device according to the present invention, which has achieved the above object, a drive shaft having a transport roller at an intermediate portion and both sides thereof is installed on one of the paper transport paths. A conveyance guide plate is provided on the other side of the sheet conveyance path so that the conveyance path can be opened, and a driven-side conveyance roller that conveys a sheet with the driving-side conveyance roller is fixed at both ends. A spring that urges and abuts the transport roller to the drive roller on the drive side is provided on the transport guide plate as a spindle, and further, in the configuration of the paper transport path, the urging force of the spring to the transport roller on the driven side of the intermediate portion. To
It is characterized in that it is set to be larger than the biasing force of the spring on the driven rollers on both sides.

[0006]

According to the above characteristic construction, when the paper to be conveyed is of a large size, it is conveyed at multiple points by the conveyance roller pair on both sides in addition to the conveyance roller pair at the intermediate portion. by the way,
If the number of transport roller pairs is simply increased, the transport guide plates will escape from the drive-side transport rollers between the transport rollers on both sides under the configuration of the paper transport path in which the transport guide plates are pressed toward the drive shaft. The conveyance force of the pair of conveyance rollers in the middle portion is reduced, and the conveyance force of the plurality of conveyance roller pairs becomes unbalanced in the width direction of the sheet, and the sheet skews or meanders. This causes inconvenience such as jamming. However, by increasing the biasing force of the spring on the driven rollers of the intermediate portion, the reduction of the conveying force due to the pair of intermediate rollers can be covered,
The carrying force by a plurality of carrying roller pairs is averaged.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an electrostatic photocopier (an example of an image forming apparatus) in which a copier body 2 is mounted on a paper feed deck 1. The above-mentioned sheet feeding deck 1 is provided with a plurality of upper and lower sheet feeding units 4 each having a sheet feeding roller 3 in the deck main body 5 and each sheet feeding unit 4
The paper transport unit 6 from the above is merged with the paper transport device 7 that constitutes an upward paper transport path, and the plurality of paper feed units 4
A front loading type paper feed cassette 8 is loaded in the.

In the copying machine main body 2, a conveying path 10 connected to the sheet discharge port 9 of the sheet conveying device 7 is provided on the lower side of the main body case 11, and a photoconductor 12 is horizontally mounted on the main body case 11.
Around the photoconductor 12, a charging device 13, a developing device 14, a transfer device 15, a sheet separating device 16, and a cleaning device 17.
Is provided. Then, the transfer device 15 is transferred from the transport path 10.
A paper feed / conveyance path 18 is provided over the paper, and a paper ejection / conveyance path 20 for feeding the paper after transfer / separation to a fixing device 19 and a paper ejection roller 22 for ejecting the paper after the fixation to a paper ejection tray 21. And an optical system movable exposure device 23 is disposed in the upper space of the main body case 11.

The sheet conveying device 7 of the sheet feeding deck 1 is constructed as follows. That is, as shown in FIGS. 2 to 4, a vertical plate on the side of the sheet feeding portion 4 of the deck body 5 is configured to be freely openable and closable around a vertical axis 24 to form an opening / closing door 25 for opening the paper transport path. On the other hand, a drive shaft 27 having two transport rollers 26 in the middle portion and a total of four transport rollers 26 on both sides thereof is installed on the deck body 5 side in association with each paper feeding portion 4, and
A transport guide plate 28 is provided on the lower side of 27.

Then, a transport guide plate 30 having an opening 29 formed at a position corresponding to all of the drive-side transport rollers 26.
Both sides of which are movably provided on the inner surface side of the opening / closing door 25 via screws a, and urging means 31 for urging the conveyance guide plate 30 toward the drive shaft 27 side are provided, and Cut-and-raised pieces b are formed on both edges of the opening 29 of the guide plate 30, and spring support members 32 having a constant spring locking height position are provided on the sides of the cut-and-raised pieces b.

Further, the driven-side transport roller 26 and the driven-side transport roller 33, each of which conveys a sheet by the driving-side transport roller 26, have the same diameter.
Facing the opening 29, the driven roller 33 on the driven side.
Is supported by springs whose both ends are fixed by spring support members 32 on both sides of the support shaft 34, and the opening / closing door 25 is closed and the opening / closing door 25 is locked by a lock mechanism 35. Under configuration,
The dimension between the rotation axis of the driven roller 33 and the driving roller 26 is larger than the dimension from the rotation axis of the driving roller 26 to the spring locking position of the spring support member 32. Set so that the driven roller on the driven side
The drive roller 33 is urged to contact the drive roller 33.

Although the spring support shafts 34 have the same length, the two intermediate transfer rollers on the driven side.
The spring constant of the spring support shaft 34 with respect to 33 is set to be large, and the biasing force of the spring support shaft 34 is set to be larger than the biasing force of the spring support shaft 34 with respect to the transport rollers 33 on the driven side on both sides. Under the configuration of the transport path, the transport force of the transport roller pair 26, 33 in the middle portion is set to be larger than the transport force of the transport roller pair 26, 33 on both sides.

According to the above construction, even if the sheet to be conveyed is large in size, the sheet is conveyed at multiple points by the middle portion and the pair of conveying rollers 26 and 33 on both sides thereof, so that both sides in the width direction can be conveyed. The feeding of the paper is stabilized, and the occurrence of jam is effectively prevented. By the way, an opening / closing door to configure the paper transport path
When 25 is closed, by the biasing force of the biasing means 31 that biases the transport guide plate 30 toward the drive shaft 27 side, the transport guide plate 30 uses the pair of transport rollers 26 and 33 on both sides as reaction force points to drive the drive side. The sheet is bent so as to escape from the transport rollers 26, and the sheet transport force by the pair of transport rollers 26, 33 in the middle portion is reduced.

However, in anticipation of this decrease in the conveying force, the conveying force by the conveying roller pair 26, 33 in the intermediate portion is set to be larger than the conveying force by the conveying roller pair 26, 33 on both sides, so a total of 4 It is possible to average the conveying force of the pair of conveying rollers 26 and 33 in the width direction of the sheet, and effectively prevent the occurrence of jam due to skew or meandering of the sheet.

In the embodiment, all the driven rollers 33 on the driven side have the same diameter, and all spring support shafts 34 have the same locking height position, so that the spring constants of the spring support shafts 34 are set. The urging force is made different by a plurality of transport rollers 26, 33.
Although the conveying force of the pair is averaged in the width direction of the paper, the following deformations are possible.

[When all the driven rollers 33 have the same diameter] 1. A spring having the same spring constant is used to shorten the free length of the spring support shaft 34 with respect to the pair of intermediate transfer rollers 26 and 33. 2. The spring constant and the free length of the spring support shaft 34 are made different. 3. A structure in which the spring constant and the free length are all the same, and the height positions at which the springs are supported by the springs 32 are different. 4. A structure in which the spring constants are all the same, the free lengths are different, and then the heights at which the springs are locked by the spring support members 32 are different. 5. A structure in which all the free lengths are made the same, the spring constants are made different, and then the heights at which the springs are locked by the spring support members 32 are made different. 6. After making both the spring constant and the free length different,
A structure in which the spring height of the spring supporting member 32 is different.

In the constructions of 1 to 6 or the construction of the embodiment described above, the diameters of the two intermediate transfer rollers 33 on the driven side are set to be larger than the diameters of the two transfer rollers 33 on both sides. It is possible to average the conveying force of 26, 33 pairs in the width direction of the paper.

In the embodiment, two driven-side transfer rollers 33 are provided in the middle portion, but it is also possible to provide only one driven-side transfer roller 33 at the center between both driven-side transfer rollers 33, or
It is also possible to adopt a configuration in which the three driven rollers 33 on the driven side are provided at predetermined intervals. When three driven rollers 33 on the driven side are provided in the middle part, one driven roller on the driven side is provided at the center.
It is important that the urging force of the spring support shaft 34 with respect to 33 be larger than the urging force of the spring support shaft 34 with respect to the driven rollers 33 on both sides thereof. Further, in the embodiment, the biasing means 31 is provided on both sides of the transport guide plate 30 provided with the driven roller 33, but the transport guide plate 30 may be fixedly provided on the opening / closing door 25. ..

Further, in the embodiment, the paper conveying device 7 of the paper feeding deck 1 has been described. For example, the paper discharging roller 22 pair and the roller pair provided in an image forming apparatus such as a facsimile may be used to convey the paper. As an apparatus, the present invention can be implemented for these.

[0020]

As described above, according to the present invention, the number of transport roller pairs is increased, and even a large-sized sheet is transported at multiple points by the transport roller pairs on the intermediate portion and both sides thereof. By doing so, the feeding of the large size paper on both sides in the width direction is stabilized, and thereby the occurrence of jam is effectively prevented.

When the number of transport roller pairs is increased in this way,
The conveyance guide plate is bent so as to escape from the conveyance roller on the drive side of the middle portion, and the conveyance force of the paper by the conveyance roller pair in the middle portion decreases, and the conveyance force becomes unbalanced in the width direction of the paper. In consideration of such a situation, by increasing the biasing force of the spring with respect to the conveyance roller on the driven side of the intermediate portion, the averaging of the conveyance force by the plurality of pairs of conveyance rollers can be achieved, and further, The occurrence of jam caused by skew or meandering of the paper has been prevented.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of an electrostatographic copying machine.

FIG. 2 is a partial perspective view of the electrostatographic copying machine showing an opened state of a sheet conveyance path.

FIG. 3 is a vertical cross-sectional plan view of a sheet conveying device of a sheet feeding deck.

FIG. 4 is a cross-sectional view of an essential part showing a shaft support state of a driven-side transport roller.

FIG. 5 is a vertical cross-sectional plan view of a conventional sheet conveying device.

[Explanation of symbols]

26 ... Drive side transfer roller, 27 ... Drive shaft, 30 ... Transfer guide plate, 31 ... Biasing means, 33 ... Driven side transfer roller, 34 ... Spring support shaft.

Claims (2)

[Claims] 1. A drive shaft provided with a conveyance roller at an intermediate portion and both sides thereof is provided on one side of a sheet conveyance path, and a conveyance guide plate is provided on the other side of the sheet conveyance path so as to be switchable to an opened state of the conveyance path. At the same time, the driven-side transport roller that transports the sheet with the drive-side transport roller is supported by a spring that is fixed at both ends and that biases the driven-side transport roller against the drive-side transport roller. It is provided on the conveyance guide plate, and further, in the configuration of the paper conveyance path, the biasing force of the spring on the driven roller on the intermediate side is set to be larger than the biasing force of the spring on the driven rollers on both sides. A paper transport device characterized by being provided. 2. The sheet conveying apparatus according to claim 1, wherein urging means for urging the conveying guide plate toward the drive shaft is provided on both sides of the conveying guide plate.