JP2003165662A - Curling device, and image-forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curling device capable of maintaining a curling effect for a sheet member and stabilizing a conveying speed, over a long period, and capable of preventing jamming in conveyance from being generated by deterioration of a roller, and to provide an image forming device having excellent sheet conveying performance using the curling device. <P>SOLUTION: In representative constitution for the curling device and the image forming device of the present invention, paired conveying rollers 3 having a sponge roller 3c having an elastic part 3a, a metal roller 3b having hardness higher than that of the sponge roller 3c, and a pressurizing spring 86 pressure- contacting to allow intershaft-moving between the sponge roller 3c and the metal roller 3b, wherein the sheet member is conveyed by conducting a drive input to the metal roller 3b to rotate the sponge roller 3c drivenly, and wherein the sheet member S is curled along a circumferential direction of the metal roller 3b, have an auxiliary roller 87 for drive transmission having a diameter size smaller than an outside diameter of the elastic part in at least one position along a longitudinal direction of a shaft in the sponge roller 3c. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curling device having a curling roller pair for positively curling a sheet material to be conveyed in a desired direction, and an image forming apparatus using the curling device.

[0002]

2. Description of the Related Art In a conventional curling device having a pair of curling rollers, a metal roller 103b is rotationally driven from a drive source (not shown) through a drive input gear 101, as shown in FIG. A sponge roller 103c, which is an elastic roller having a foamed urethane rubber portion 103a in its elastic portion, is fixed to a metal roller 103b between fixed axes, and is pressed against the metal roller 103b so as to form a desired nip shape. Drive transmission to the sponge roller 103c is performed by the gear 105 and the gear 106.

Further, in the conventional example shown in FIG. 6, the metal roller 203b is rotationally driven from a drive source (not shown) through a drive input gear 201. A sponge roller 203c, which is an elastic roller having an elastic urethane rubber portion 203a in its elastic portion, is axially supported by the metal roller 203b so as to be movable between the axes. Pressing springs 205 provided at both ends of the shaft are pressed against each other so as to form a desired nip shape. Sponge roller
The drive transmission to 203c is performed only by the frictional force between the metal roller 203b and the foamed urethane rubber portion 203a.

By thus transporting the sheet material between the pressure-contacted nips, the metal rollers 103b and 203b are conveyed.
Curls in the circumferential direction.

[0005]

However, in the case of the prior art of fixed shaft / double-sided drive shown in FIG. 5, the initial nip shape is reduced due to the decrease of the outer diameter of the foamed urethane rubber portion 103a due to deterioration of durability. There is a problem that the desired amount of curl cannot be obtained because it cannot be maintained. Further, based on the nip shape at the initial outer diameter, the gears 105, 106 are arranged so that the peripheral speeds of the metal roller 103b and the sponge roller 103c become equal.
However, in the above configuration, there is a problem in that the peripheral speed difference occurs due to a decrease in the outer diameter of the foamed urethane rubber portion 103a due to deterioration in durability and the sheet material conveying speed becomes unstable.

On the other hand, the spring pressure applied to move between the axes shown in FIG.
In the case of the conventional technique of driving a metal roller, the curl urging effect and the conveying speed are stable, but the hardness of the foamed urethane rubber portion 203a due to deterioration of durability and ozone deteriorates, and as a result, the frictional force between the rollers decreases. I will end up. Therefore, when the hardness is reduced by more than the specified amount, the sponge roller 203c slips, the rotational drive is not transmitted, and the sheet material cannot be conveyed, resulting in a jam.

Therefore, the present invention is capable of maintaining the curling effect of the sheet material, stabilizing the conveying speed for a long period of time, and preventing the conveying jam due to roller deterioration, and a curling apparatus using the same. An object of the present invention is to provide an image forming apparatus having a good sheet material conveying performance.

[0008]

In order to solve the above-mentioned problems, a typical structure of a curling device and an image forming apparatus according to the present invention is a first roller having an elastic portion, and a hardness higher than that of the first roller. High second roller and the first and second rollers
Roller pressing means capable of press-contacting the roller so as to be movable between the axes, the sheet material is conveyed by drivingly input to the second roller, and the first roller is driven to rotate, and the second roller In the curling device capable of curling the sheet material in the circumferential direction of the roller, at least one position in the longitudinal direction of the shaft of the first roller has auxiliary rollers for driving transmission smaller than the outer diameter of the elastic portion. Characterize.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a curling device and an image forming apparatus according to the present invention will be described with reference to the drawings. 1 is a perspective view of a curling device (before endurance), FIG. 2 is a perspective view of the curling device (after endurance), FIG. 3 is a cross-sectional view of an image forming apparatus using the curl applying device, and FIG. 4 is an intermediate sheet material. It is a detailed sectional view of a loading device.

First, the overall structure of the image forming apparatus equipped with a curling device along the flow of the sheet material is shown in FIG.
It will be described based on.

As shown in FIG. 3, cassettes 51, 52, 53, 54 arranged at predetermined positions in the lower half of the image forming apparatus 50 in the figure.
The sheet material S inside is picked up by pickup rollers 55 and 59, and separated into one sheet by separation means 56 and 60,
It is conveyed upward in the figure by the conveying roller pair 57.

The image of the original document 74 is exposed on the photosensitive drum 61 by the optical means 75 to form a toner image on the photosensitive drum 61. The toner image on the photosensitive drum 61 and the above-described sheet material S are conveyed in the direction of the photosensitive drum 61 in synchronization with each other by the registration roller pair 58.

Next, the toner image on the photosensitive drum 61 is transferred onto the sheet material S by the transfer charger 62. The transferred sheet material S passes through the fixing device 64, and the toner on the sheet material S is fixed.

Next, the double-sided image mode or the multiple image forming mode will be described. FIG. 4 is a detailed view of the intermediate sheet material stacking device A.

As shown in FIG. 4, the sheet material S on which the above-described first image formation has been completed is guided to the intermediate tray transport path 2 via the entrance guide 1. Then, the sheet material guided to the intermediate tray transport path 2 is sent to the discharge roller pair 4 by the transport roller pair 3 as a curling roller pair, and is discharged onto the intermediate tray 5 by the discharge roller pair 4.

The sheet material discharged onto the intermediate tray 5 is
When the position of the end portion of the sheet material is regulated by the side regulation member (not shown), the rear end regulation member 11 installed on the intermediate tray 5 is moved in the direction of arrow X in FIG. 4 by the driving force of the motor (not shown). Moving. As a result, the leading edge (the trailing edge when discharging) moves on the intermediate tray 5 until it reaches the re-feedable position (the position lower than the feeding roller 12).

When the sheet material is discharged onto the intermediate tray 5, the trailing edge regulating member 11 has a predetermined distance from the position where the leading edge (the trailing edge when falling) of the sheet material falling on the intermediate tray 5 is located. Standby at a distance (for example, 30 mm).

The rear end regulating member 11 is adapted to move along a guide 5A formed in the sheet material conveying direction.

When the predetermined number of sheets S of sheets after the first image formation are stacked on the intermediate tray 5, the feeding roller 12 rotating counterclockwise in the figure is stacked on the intermediate tray 5. The leading edge of S is pressed from above to enhance the conveying force, and the sheet material is reliably fed out.

The sheet material S fed by the feeding roller 12 is separated and fed one by one by a separating / feeding device 15 comprising a feeding roller 13 rotating counterclockwise in the figure and a separating belt 14 rotating counterclockwise. Will be sent.

In the double-sided image forming mode, the flapper 16 is set at the position 16a, and the separation feeding device
The lowest sheet material separated and fed by 15 is sent to the re-feed path 18 by the pair of registration rollers 17 whose rotation is stopped.

In the multiple image forming mode, the flapper 16 is set to the position 16b, and the separation feeding device
The lowermost sheet material separated and fed by 15 is fed to the multi-pass 19 and is conveyed to the pair of conveying rollers 20 until the trailing end of the sheet material passes the flapper 16.

Then, after the trailing edge of the sheet material passes through the flapper 16 and is conveyed by the conveying roller pair 20 which rotates in the reverse direction to the registration roller pair 17 which is not rotating, and the skewed state is corrected,
It is sent to the re-feed path 18 by the pair of registration rollers 17.

In the above sheet material flow, as shown in FIG. 3, after passing through the fixing device 64, the sheet material is conveyed downward in the drawing (on the side of the intermediate sheet material stacking apparatus A), and then the intermediate tray transport path. Although the sheet material S passes through 2 and is stacked on the intermediate tray 5, the sheet material S that has passed through the fixing device 64 is curled upward, and when the sheet material S is stacked on the intermediate tray 5, the trailing edge regulating member. When the sheet material is moved at 11 or the like, the sheet material may be curled, and thus the movement may not be possible.

Therefore, in this embodiment, in order to remove the curl, a pair of conveying rollers 3 is provided as a curling device. As shown in FIG. 1, the transport roller pair 3 includes a sponge roller 3c that is a first roller and a metal roller 3b that is a second roller.

The sponge roller 3c has a metal shaft having a diameter of 8 mm and an elastic portion 3a having a diameter of 20 mm made of expanded urethane rubber. That is, the thickness of the elastic portion 3a is 6 mm. Further, the metal roller 3b has a diameter of 9 mm, and the elastic portion 3
It is formed to have a hardness higher than that of a, and rotational drive is input from a drive source (not shown) through the drive input gear 81 in the sheet material conveyance direction.

On the other hand, side plates 82 for supporting the sponge roller 3c and the metal roller 3b are provided at both ends in the axial direction of the curling roller pair (sponge roller 3c, metal roller 3b), and the bearings 83, 84 are sponge. The roller 3c and the metal roller 3b are rotatably fixed to the side plate 82.

On the side plate 82, the sponge roller 3c is provided.
Is provided with an elongated hole portion 85 for enabling inter-axis movement toward the metal roller 3b.

A space between the sponge roller 3c and the metal roller 3b is pressed by a pressure spring 86 which is a roller pressing means to which a load of about 2.5 kgf is applied on one side, and the wall thickness 6 mm of the elastic portion 3a is about 4 mm, that is, the penetration. It is configured to form the desired nip shape with an amount of 2 mm.

In the system at the initial stage of durability shown in FIG. 1, the sponge roller 3c is a driven roller, and the drive transmission force from the metal roller 3b depends on the hardness of the elastic portion 3a and the spring force of the pressure spring 86 to generate a reaction force N. It is determined by the frictional force μ between the elastic portion 3a and the metal roller 3b depending on the above.

When the sheet material S enters the nip of the curling roller pair (sponge roller 3c, metal roller 3b), the sheet material S is conveyed along the outer diameter of the metal roller 3b and curled in the circumferential direction. As a result, the upper curled sheet material S is decurled.

In the above structure, as the number of sheets of the sheet material S conveyed increases, the frictional force of the elastic portion 3a decreases due to durability. Further, the hardness of the elastic portion 3a is remarkably reduced due to ozone deterioration and hydrolysis of the foamed urethane due to ozone generated from the inside of the image forming apparatus.

FIG. 2 shows a state in which the elastic portion 3a has deteriorated in durability. The reduction in the hardness of the elastic portion 3a narrows the distance between the shafts, and a thickness of 6 mm is about 3 mm, that is, a nip is formed with a penetration amount of 3 mm. In this state, the auxiliary roller 87 of φ14 mm made of EPDM solid rubber is fixed to the end of the sponge roller 3c integrally with the roller shaft.
And press.

The auxiliary roller 87 transmits the drive force from the metal roller 3b to the sponge roller 3c when the space between the sponge roller 3c and the metal roller 3b becomes narrower than a certain distance. Further, the auxiliary roller 87 has a hardness higher than that of the elastic portion 3a even after durability, and has a high resistance capable of reliably transmitting drive from the metal roller 3b to the sponge roller 3c without idling when pressed against the metal roller 3b. It is made of material.

In the highly durable system shown in FIG. 2, the sponge roller 3c is a driven roller, and the drive transmission force from the metal roller 3b depends on the reaction force N proportional to the spring force of the pressure spring 86. The frictional force μ between the auxiliary roller 87 and the metal roller 3b determines the friction force.

When the sheet material S enters the nip of the curling roller pair (sponge roller 3c, metal roller 3b), the sheet material S is conveyed along the outer diameter of the metal roller 3b and is curled in the circumferential direction. As a result, the upper curled sheet material S is decurled.

The material for the auxiliary roller 87 may be selected as long as it has a high hardness and a high frictional force with the metal roller 3b even after the durability, as compared with the elastic portion 3a. The same effect can be obtained even if the surface is coated with a friction-enhancing coat.

In the present embodiment, the pair of curling rollers is explained by taking the pair of conveying rollers 3 and the pair of discharging rollers 4 in the intermediate sheet material stacking apparatus A of the image forming apparatus as an example. The same can be applied to the pair of sheet material conveying rollers such as the pair of curling rollers before the registration roller for improving the sheet material.

As described above, since the auxiliary roller 87 for driving transmission, which is smaller than the outer diameter of the elastic portion, is provided at least at one position in the longitudinal direction of the shaft of the sponge roller 3c, the roller shafts of the sponge roller 3c and the metal roller 3b are provided. When the distance between the metal roller 3b and the sponge roller 3c becomes narrower than a certain distance due to deterioration of durability, drive can be transmitted to the sponge roller 3c, and the sponge roller 3c is prevented from stopping.
It is possible to surely prevent a conveyance jam due to a poor rotation.

Further, by making the auxiliary roller 87 of a material having a high resistance, it becomes possible to reliably transmit the drive force from the metal roller 3b to the sponge roller 3c even in a system in which the space between the axes is narrowed and the applied pressure is reduced. .

Further, by making the hardness of the auxiliary roller 87 higher than that of the elastic portion 3a of the sponge roller 3c, the drive can be reliably transmitted from the metal roller 3b to the sponge roller 3c, and the desired nip shape can be maintained. , The curling effect of the sheet material can be stably obtained.

By using the curling device for the pair of transport rollers 3 for transporting the sheet material, it is possible to stabilize the transport speed for a long period of time even when the service life reaches the end of service life. It is possible to prevent the conveyance jam caused by the deterioration of the rollers and to convey the sheet material well.

[0043]

As described above, by providing at least one position in the longitudinal direction of the shaft of the first roller, the auxiliary roller for drive transmission smaller than the outer diameter of the elastic portion,
When the distance between the first and second roller shafts is narrowed by a certain distance or more due to deterioration of durability, it becomes possible to transmit drive from the second roller to the first roller, avoiding the sponge roller from stopping, It is possible to surely prevent a conveyance jam due to a poor rotation.

Further, by using a material having a high resistance for the auxiliary roller, it is possible to reliably transmit the drive force from the second roller to the first roller even in a system in which the pressure between the axes is narrowed and the applied pressure is reduced. Become.

Further, by making the hardness of the auxiliary roller higher than that of the elastic portion of the first roller, the drive can be surely transmitted from the metal roller 3b to the sponge roller 3c, and the desired nip shape can be maintained. The curling effect of the sheet material can be stably obtained.

By using the curling device as the conveying roller for conveying the sheet material, even when the end of the life is reached from the beginning of the endurance, the conveyance speed can be stabilized for a long period of time, and the roller deterioration is caused. It is possible to provide a curling device capable of preventing a conveyance jam caused by the above and an image forming apparatus having a good sheet material conveyance performance using the curling device.

[Brief description of drawings]

FIG. 1 is a perspective view (before endurance) of a curling device.

FIG. 2 is a perspective view (after endurance) of the curling device.

FIG. 3 is a sectional view of an image forming apparatus in which a curling device is used.

FIG. 4 is a detailed cross-sectional view of an intermediate sheet material stacking device.

FIG. 5 is a perspective view of a conventional curling device.

FIG. 6 is a perspective view of a conventional curling device.

[Explanation of symbols]

A ... Intermediate sheet material loading device S ... Sheet material 1 ... Entrance guide 2 ... Intermediate tray transport path 3 ... Conveyor roller pair 3a ... Elastic part 3b ... Metal roller 3c ... Sponge roller 4 ... Ejection roller pair 5 ... Intermediate tray 5A ... Guide 11 ... Rear end regulating member 12… Feeding roller 13… Feed roller 14… Separation belt 15-Separate feeding device 16 ... flapper 16a… position 17… Registration roller pair 18… Refeed Pass 19 ... multiple passes 20… Conveyor roller pair 50… Image forming device 51 ~ 54 ... cassette 55, 59 ... Pickup roller 56, 60… Separation means 58… Registration roller pair 61… Photosensitive drum 62… Transfer charger 64… Fixer 74 ... manuscript 75… Optical means 81… Drive input gear 82 ... Side plate 83, 84… Bearing part 85… Oval hole 86… Pressure spring 87… Auxiliary roller

Claims (4)

[Claims] 1. A first roller having an elastic portion, and the first roller.
Second roller having a hardness higher than that of the first roller, and roller pressing means capable of press-contacting the first and second rollers so that the first and second rollers can move between the shafts. The sheet material is conveyed by rotating the roller of
A curling device capable of curling a sheet material in the circumferential direction of the second roller, wherein at least one position in the longitudinal direction of the shaft of the first roller has an auxiliary roller for drive transmission smaller than the outer diameter of the elastic portion. A curling device having: 2. The second roller ensures that the auxiliary roller does not run idle when pressed against the second drive roller, even if the distance between the shafts decreases as the elastic portion of the first roller changes over time. The curling device according to claim 1, wherein the curling device is made of a high-resistance material capable of drivingly transmitting from the roller to the first roller. 3. The curling device according to claim 1, wherein the auxiliary roller is made of a material having a hardness higher than that of the elastic portion of the first roller. 4. An image forming apparatus, wherein the curling device according to claim 1 is used as a carrying roller for carrying a sheet material.